Tag Archives: Toe Overlap

Rider Height, Wheel Size, and Not Compromising

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A conversation we have with a lot of customers is about how the size of their bike can impact the handling and performance. This is an issue that mainly comes up with bikes for riders under 5’6″. The problems always stem from trying to fit 700c wheels into a small frame. Compromises have to be made and these compromises are felt by the rider.

The first problem is toe overlap. As the frame gets smaller the front wheel gets closer to the crankset and the rider’s feet. This can result in the toe hitting the wheel in a turn, aka toe overlap. To compensate for this, many manufacturers resort to a slacker head tube angle. This puts the wheel further in front of the bike and causes sluggish handling. If the bike is small enough, you can end up with both problems anyway.

The seat tube is similarly affected. It’s often steeper to reduce the overall rider reach. This puts the rider pretty far forward over the bottom bracket and can cause fit issues resulting in stress to the knee. None of this is good for the rider. Fortunately, there’s an obvious solution: smaller wheels.

While this seems like a no-brainer, it’s historically been a difficult sell to many customers. They have a lot of reasons, but they usually boil down to either “700c wheels are faster” or “My riding buddies will literally make fun of me if I show up with smaller wheels”. While we can dispel the myth of the first one, the second one can be harder to overcome.

The myth of 700c wheels being faster is an old one. There are a lot of factors that go into making a bike fast, and wheel size isn’t really one of them. Bikes that hold the world speed records do it on smaller wheels than any race bike comes with, and this is due to strength issues, not speed considerations. We have an in depth article about wheel size here, and you can read an outside opinion here that tackles this exact myth and explains effectively why it’s rubbish. Thankfully, the rise in popularity of the 650b/27.5″ wheel has made it much easier to sell customers on smaller wheels.

Take a look at the three photos in this post. While these bikes have very similar angles and proportions, they are for three people of very different heights. This because all three use a different wheel size. The top bike is a 700c Bandito, the middle bike is a 650b Bandito, and the bottom bike is a 26″ Phinney Ridge. The great thing is that all of these bikes have a trail of about 60mm, which means they all steer and handle the same. Now people can get a bike that handles properly no matter how tall they are. All this with no toe overlap issues and room for larger tires as well. (If you’re curious about larger tires, click here and here)

So now you know there’s no reason to own a bike that doesn’t handle well just because of your size. There’s more choice in wheel and tire size than ever before so you don’t have to compromise anything to get a bike that works just the way you want it to. As for friends who think they know better, there’s nothing wrong with educating them about their misconceptions. The proof will be in the riding.

Why not 26 Inch Wheels instead of 650c?

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Since our series on 700c vs. 650c ran, I’ve gotten a lot of e-mail questions about 26″ (mountain bike sized or 559 size) wheels.

The question that people have is “why don’t you use mountain bike sized wheels instead of 650c? Wouldn’t that give the customer more rim and tire choices?”

Related Items
Find wider 650c tires at
650biketires.com

See photo galleries of 650c bikes at www.rodbikes.com

See photo galleries of 26″ bikes at www.rodbikes.com

The funny thing is, we love 26″ wheels as well. 26″ wheels offer all of the same design advantages for the petite cyclist as the 650c. Actually, we build a lot more bikes with 26″ wheels than we do with 650c. I’ll bet we build more 26″ wheeled road bikes than just about any other custom builder around. One quick look at our website, and you’ll see that we have several models that use 26″ wheels for every frame size, and all of our touring bikes come standard with 26″ wheels for all of the smaller sizes. Our popular UTB has run 26″ wheels since 1996, and the Rodriguez Adventure touring bikes have run 26″ wheels for the small sizes since the creation of the model as well. We were a pioneer in 26″ wheeled tandems and touring bikes throughout the 1980’s and 1990’s, and still offer 26″ wheels on any tandem or touring bike we make. As a matter of fact, more than half of Rodriguez tandem riders (including myself) choose 26″ wheels. Just look at our main photo on our custom tandem page or the Toucan ST tandem page. Almost all of our new Rodriguez Make-shift customers order their bike with 26″ wheels as well. I can’t leave out our exclusive Rodriguez 8-ball convertible tandem/single travel bike either. Since it’s inception in 1995, all but 2 of these have been built for 26″ wheels (one went with 700c, and one went with 24″ wheels). Here’s a gallery with just a few of the 650c bikes that we’ve built last year alone.

As you can see, 26″ wheels have a very long history on Rodriguez bicycles

This series of articles was focused on road racing bikes, and there is a disadvantage to a 26″ wheel on a road racing bike. That disadvantage is tire and rim availability. Although there are plenty of rims and tires available for 26″, the selection that a racer would want to use is extremely limited. 650c offers a decent selection of lightweight racing tires from 23mm to 28mm by companies like Michelin, Vredstein, Serfas, Continental, Hutchinson, etc… 26″ offers the rider great variety in wider touring tires, but almost no 23mm options, and very few light weight rim options.

Road Race bikes are a different animal than tandems or touring bikes
For a couple of years, we ran 26″ wheels on the smaller our best selling Rodriguez Rainier road model, but we found that rim and tire choices were too limited for some of our ‘go-fast’ road bike customers needs.

A Rodriguez Rainier built to accomodate 650c or 26 inch wheels

This bike is shown with 26″ X 1.25″ wheels, but the owner, Nancy, has a pair of 650c racing wheels that she runs for “race day”

In a perfect world, the industry would begin manufacturing 26″ tires and rims in racing weights, or 650c rims and tires in touring weights. But for now, the petite racer has a much better selection on 650c, and the touring cyclist has a plethora of excellent choices in 26″.

Why not a bike for both 26″ and 650c?

What’s really cool is a bike that will use both 650c and 26″. We’ve built several of these through the years, but requires some special considerations when it comes to brakes. Standard brakes will not work for both wheel diameters, but if the rider is willing to adjust their brakes, they can have a bike like Nancy’s (above), that can use both wheel sizes.

In summary, nobody would like to see the acceptance of one standard wheel size than I, but suffice it to say we will continue to offer the petite cyclist choices that suit their style of riding in any wheel size.

To see more 26″ and 650c wheel bikes, visit our website and look through the image galleries for the different models. Every image gallery has bikes with various wheel sizes. To get you started, here is a gallery of just some of the 650c bikes that we’ve built last year alone.

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What’s the effect of wheel size on speed?

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This is part 8 of 8. Here is the start!

When someone in the industry (people in the industry should know better) tells a smaller rider “small wheels are slower”, what I hear them saying is “riding with knee pain, discomfort in your shoulders, neck, back and numbness in your hands on a bicycle that’s harder to control can make you ride faster.” This doesn’t sound like good advice to me. Especially when there’s so much proof that their “smaller=slower” claim is completely false.

Related Items
Find wider 650c tires at 650biketires.com

See photo galleries of 650c bikes at www.rodbikes.com

The truth is, when someone tells you “smaller wheels are slower”, what they are saying is “I have nothing with proportional wheels to offer you”. At Rodriguez, we’ll offer you either size, and give you the facts about both.

There’s really two myths that people are told about why 650c wheels are slower than 700c. We can easily put the facts together to show that both of these theories, while having some truth in them, ignore several other aspects of the differences. Those differences easily offset the reasoning that is used by so many in bike shops around the country to try and scare petite riders into bigger wheels.

Warning: Severe Facts Ahead

Slow myth 1.) Salesperson says “Smaller wheels have to make more rotations to travel the same distance.”

This part is true. A 650c wheel has to turn 823 rotations to travel 1 mile, while a 700c wheel has to rotate 763 times for the same distance. Salesperson says “More rotations = more friction in the bearings and that causes you to go slower.” …..not exactly. All other things being equal, this would be true, but there’s more to the equation.

What the salesperson doesn’t know, or has neglected to inform you of is that the 650c wheels are 8% lighter than the exact same wheels built in 700c. Think about it. A smaller rim, shorter spokes, smaller tire, tube and rim strip all add up to big weight savings for the 650c. Just for fun, ask that same salesperson if heavier wheels are faster than lighter wheels? We all know of course, that lighter wheels are the best way to speed up any bicycle. You could also ask him what wheel size is used on bicycles that hold land speed records? That’s because of those darn facts again. This time it’s rotational mass….read on and see what I’m talking about.

Friction, Bricks, and Rotational Mass
When an object (like a bicycle wheel) is spinning, it is subject to the laws of rotational weight. Rotational weight is the ‘evil’ that everyone with any size of wheel is trying to get rid of. This is because of rotational mass. Imagine a brick tied to the end of a string. Pretty easy to hold up right? Now swing the brick around in a circle. It feels much heavier. If the brick is lighter and the string is shorter, then it’s easier to spin. Rotational weight of a wheel is magnified in this same way. As a wheel starts to spin, all of the weight out at the end of the spokes is ‘the brick’. Less rim, spoke, tire, tube, etc. equates to a ‘lighter brick’ to spin, and a smaller diameter equates to a shorter string. A lighter wheel is much easier to spin up to speed than a heavier one.

Need more scientific evidence than a ‘brick on a string’? Here’s a scientific article detailing the effect of weight and size on the rotational mass of a spinning object.

“C’mon Dan! That article was way techo-geek speak!” “How about some easy proof that everyone can understand?”
How about a spinning ice skater? Here’s a quick article of how an ice skater speeds up their spin. By pulling their arms closer to their body, they pick-up speed right?

In short
The 8% weight savings for the 650c wheel sizes easily negates the added friction for the additional rotations that it makes.

Slow myth 2.) Salesperson pulls out a gear chart and illustrates to the customer “Smaller wheels mean that you have to turn the cranks more revolutions to travel the same distance.”

Rant Warning
I’m sorry, but I have to pause here to say, if a salesperson ever says that to you, find a way to politely leave the store. You’re either dealing with someone who’s trying to mislead you, or they really don’t know what they’re talking about. Either way, I recommend finding another shop. I’ve had people come to my shop who’ve been told this very thing by dealers who know better.

OK, rant time is over and now it’s time to educate you on why gearing shouldn’t even be an issue in this topic.

Gearing
We’ve already established that one rotation of a smaller wheel is a shorter distance that one rotation on a larger wheels right? So wouldn’t one rotation of your cranks results in less forward motion too? Actually, it has all to do with gearing ratio, and nothing to do with wheel size. Now, if you put exactly the same size gears on the 2 different bikes, then the statement would technically be true, but that would be stupid. The gear ratio is selected for your style of riding and your strength. It’s the same on a car. A Porsche with small wheels is geared higher than a dump truck. The Porsche with smaller wheels is faster than the large wheel dump truck because the Porsche is geared for higher speed. Does that make sense? We use higher gearing to accommodate for smaller wheels, and lower gearing to accommodate for larger wheels. We can make any wheel size any gearing.

In the bike industry, gear inches are calculated the following way:
(Front chain ring size) ÷ (cog size) x (wheel diameter). For 700c x 25mm tires, use 26.77 for the wheel size. For 650c x 25mm tires, use 24.8 for the wheel size.

As you can see in the sample below, a simple change of one tooth size on the cog or chain ring is all that is required to gear the bikes almost identically. Actually, in the sample below, the 650c wheel bike is geared higher than the 700c. Any shop worth dealing with is going to work with you to determine the right gear ratio for your riding style and strength at no charge anyway.

Here’s a quick sample of a common road bike gearing for three different wheel sizes
Wheel size Front Chain rings Rear Cogs Highest Gear Lowest Gear
700c wheel 52/39 12-24 116 inches 43 inches
650c wheel 52/40 11-23 117 inches 43 inches
24″ wheel 55/42 11-21 113 inches 44 inches

You can easily see now that it’s misleading to assume that all bikes have to use the same gear sizes when showing someone a gear chart. Gearing is a non-issue when it comes to speed and wheel size.

Slow myth 3.) All serious riders ride 700c. Nobody fast rides small wheels.

“OK, these are all great facts, but are there any world class athletes that ride smaller wheels to victory?” You ask?

Well, I’m glad you asked. You could listen to what Stacia has to say. She set the cycling speed record for the Seattle Danskin Triathlon.

You could take

Lee’s word for it (if you can catch up with her).

Maybe you’d like to talk to Anna after she won first place in her first Olympic distance triathlon.

No you haven’t hear of these people, but if you’re a petite cyclist, chances are you’ve seen them kicking the shorts off of folks out there in the ‘regular people’ world of cycling that we all live in. We’ve got thousands of customers out there like Nancy B. who thought 650c wheels would be slow, but have discovered how fast they are.

Again, I’m not trying to say that smaller or bigger wheels are faster or slower, and I don’t care what wheel size that you want to ride. I ride 700c wheels on my road bikes, and 26″ wheels on my tandems. I think that it’s important though that you understand that choosing smaller wheels to make your bike fit will not make you slower.

Are smaller wheels just for the ladies? How about something for the guys? Are there any tall guys who choose to ride smaller wheels professionally? Yes! Some of the worlds fastest bicycles were piloted by men and have really small wheels.

Obviously if bigger wheels were faster, one would expect to find bigger wheels, not smaller wheels, on record setting bicycles that are ridden at speeds of over 150mph. Yet, these guys chose really small wheels. Maybe they didn’t talk to the guy at the shop.

Don’t believe me? Ask these guys and (gal).

World Record holding Bike with small diameter wheels

Al Abbott sets the world record riding past 138 mph in 1973

Another World Record Speed Holder with tiny wheels on his bike

John Howard sets the world record at 152.2 mph in 1985

Laurent Jalaber climbing on a 650c wheeled bike during the Tour de France

Famous sprinter Laurent Jalaber becomes a climbing champion on a 650c bike in the 2001 Tour de France

Women's bicycle Land Speed Record - Denise Mueller
Denise Mueller sets the women’s world record at 147mph in 2016
Fred Rompelberg holds the current bicycle speed record at 167mph set in 1995
Fred Rompelberg’s record setting ride of 167mph in 1995 was achieved with really small wheels

Examples like these are easy to find, and number in the thousands. Again, I’m not saying smaller wheels are faster, but just that wheel size isn’t determinant of speed.

Still have some questions? email me, I’ve got plenty of testimonials and other articles on the subject. I’ve got no incentive to push either wheel size, and I own bicycles with both wheel sizes. I just hate to see people receive bad information and get a bike that doesn’t control well and isn’t comfortable.

The Real Cause of “Slow”
One thing that everyone can agree on is that discomfort, pain, and low confidence for controlling a bicycle will always result in slower riding. This isn’t even up for debate. Feeling comfortable and in control is the best way to speed up your ride. When the industry (or bike shop) is telling smaller riders “bigger wheels are faster”, I think what they mean to say is “make my job easier by compromising the comfort, fit, and confidence that taller riders experience.”

The real truth is that Comfort and Confidence = Better Performance and Faster Speed.

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Wheel size Cliff Notes

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This is part 7 of 8. Here is the start!

A quick summary of the compromises that have to be made when designing bicycles for people under five feet, five inches tall.

Compromise 1, Accept Toe Strike
Some manufacturers choose to compromise safety instead of handling. By designing a bike for proper trail numbers, and a short top tube, this manufacturer has designed a bicycle that is very dangerous when trying to avoid an obstacle (like a car door or pedestrian) when riding. At Rodriguez Bicycles, we no longer build with this much toe strike because we have had to buy back so many small bikes over the years for this reason. No matter what someone tells you, you’re not going to get used to it, and too much toe strike is not OK.

This drawing is an exact re-creation of an actual bike that came in for repairs because the customer crashed while trying to avoid a car door. The rider was confused as to why they went down, but was sure they didn’t hit the car door.

The picture on top shows that the bike looks perfectly fine, and normal to the untrained eye. The fit measurements line up just right for most women around 5’3″ tall. The same drawing on the bottom shows the issue of toe-strike.

Frame drawing with toe overlap

Frame drawing with toe overlap highlighted

Compromise 2, The Magic Top Tube
On the face of things, this second bike has no toe overlap, acceptable handling geometry, and the right fit numbers. What the untrained eye doesn’t see here is that this is actually a trick. The seat tube angle has been designed very steep, so the top tube is artificially shortened. This way the manufacturer can list the bike in a catalog with a short top tube.

In real life, this is the worst compromise for most riders because it makes the reach almost impossible to shorten. Riders that have bikes like this soon find out that their knee is way too far forward and they have developed knee pain when they ride long distances. The only way to correct it is to push the seat way back, effectively lengthening the reach to the bars too far for a shorter rider. Now the rider needs a stem that’s shorter than any thing available. Unless your fit numbers call for a really steep seat angle, I recommend against this option.

On the top, you can see that this bike looks normal. On the bottom, you see that this is actually the worst way to design a small bike with 700c wheels if you consider fit and control as important. Many, many companies use this slight of hand to pass off a small bike as ‘women’s specific’ design.

frame drawing with sneaky geometry

frame drawing with sneaky geometry highlighted in red

Compromise 3, Ignore Control All Together

One way to get the big wheel out of the way of the rider’s foot is to slacken the head tube angle…..a lot…like a chopper. This option says “let’s build the bike to fit right, and we don’t care how it handles”. The bike drawn below is an exact re-creation of an expensive titanium custom bike that a 5′ 2″ tall woman brought in because it didn’t handle well. When I rode the bike, I would liken the handling to my grandfather’s 1966 Ford pickup without power steering. ie….it was a chore to steer this bike.

Although this option allows for a carbon fork, I suggest strongly that you try it for a weekend before you invest in a bike built like this. I also suggest that you try compromise 4 and 5 as well. I think that you’ll find that handling characteristics are much more important that you may think.

On the top, you can see that this bike looks normal to the untrained eye. On the bottom, you can see the result of a ‘chopper-style’ front end.

chopper bike frame drawing

chopper frame drawing with huge trail number pointed out

Compromise 4, Go Old-Style
The very best way to put a 700c wheel on a smaller bike is the same way that we used to do it in the 1970’s and 1980’s…..use a steel fork. By using a steel fork, we have the option to put a custom amount of rake in the fork to offset a slack steering angle. This keeps the handling characteristics correct, and allows us to build to the proper fit and knee angle.

Proportional wheels are always going to give the bike better handling, but this compromise will allow those who really want 700c on a small bike to have them. The drawbacks to this option are that the fork ends up being heavier, and you still have some issues related to large wheels on a smaller bike. Read what what a serious athlete of smaller stature has to say on that subject.

On the top, you can see that this bike looks normal to the untrained eye. Actually, it looks (and rides) a lot like the an old Peugot or Raleigh from the 1970’s. On the bottom, you can see that it results in pretty satisfactory numbers as well. This option is preferable to 3 previous options, but doesn’t really provide the petite rider with the same level of quick handling and control that the taller riders get on their bikes.

frame drawing with a custom fork

Pointing out on the same drawing at left the custom fork angles

Compromise 5, Perfectly Proportional but more limited selection of tires
The very best way to build a smaller bike considering handling, comfort, fit, and speed is to use wheels that are proportional to the frame size. Using a 650c wheel allows the builder to correct for all of the drawbacks listed above and use lighter wheels and carbon fork as desired.

The drawbacks to 650c wheels are that your tire choices are more limited. The cycling industry ignores the needs of female cyclists to a very large extent, and stocking 650c tires just isn’t cool. If you ride widths from 23mm to 28mm, and you don’t mind carrying a spare, then you’ll have no problems with 650c.

On the top, you can see that this bike looks well designed and proportional. On the bottom, you can see that all of the fit measurements are right, as well as the handling geometry. The only compromise being a more limited tire selection. The petite rider can experience the exact same performance and control as taller riders do on their bikes.

Frame drawing with a 650c wheelset

Frame drawing with 650 wheels showing no toe overlap, normal trail numbers and a proportional top tube length

There you have it. A full graphic illustration of the ups and downs of wheel sizes and smaller bikes. A lot of smaller riders and women get a lot of advice from friends who ride, but aren’t actually bike designers. We’re happy to build your smaller bike with 700c or 650c wheels. I think that it’s important that you consider the differences as explained by someone who designs bicycles for a living.

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Small Bike Compromise: Sacrifice Convenience?

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This is part 6 of 8. Here is the start!
A quick overview of terms that are important:

  • Fork Rake – Offset that places the fork ends ahead of the steering axis
  • Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
  • Trail – The distance that the axle trails the steering axis intersection with the ground
  • Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
  • Reach to Bars – Distance from center of seat to center of handle bar stem
  • Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
  • Seat Tube Angle – The angle of the seat tube in relation to the ground
  • Toe Strike – How much of the foot interferes with turning the front wheel

A Bike with 650c wheels, proportional to the frame

Compromise 5.) Sacrifice convenience:
Here’s an idea….why not go to the extra expense and use a proportional sized wheel on the bikes that are smaller? This is the method that companies use when they are trying to provide the best fitting bikes without compromising safety or good performance. It also costs more for the manufacturer, and requires commitment and understanding of their customer’s needs. 650c wheels provide a world of design upgrades to the shorter rider, and should not be mis-understood.

That being said, there is a drawback to them. The drawback is that there are fewer tire choices for 650c, and there are not a lot of shops that stock 650c tires. So, you’ll want to have a spare if you’re on a long tour. Other than that, there are no drawbacks to a 650c vs. a 700c tire.

Now, I realize that some customers want special tires or rims that are only available in 700c, and are willing to sacrifice the weight or performance of proportional wheels, and I have no argument with that. We’re happy to, and do build a lot of smaller bikes with 700c wheels. I do have an argument with shops that say things like “smaller wheels are slower”, or “there’s no compromise in it” when science and physics prove differently. Facts are stubborn things I guess.

Alright! Women and shorter riders, you make the decision. Do you want the same comfort, control and performance as the taller riders get? Or, would you rather have the same wheel size that the taller riders get? It doesn’t matter to us, as long as you are making an educated decision.

WOW! Are you still reading this? If so, you’ve probably got more questions. I’m happy to answer any of them regarding this issue. I’m dumbfounded as to why some folks out there almost get angry about this subject, but it seems like they do. Back in the days before 650c wheels were common, we used to use 24″ wheels for small bikes. Imaging how mad that would make those people 🙂 Anyway, shoot me an email if you have any questions about this article. It’s a technical article, and really could be a book if I went into every aspect of the issue. Suffice it to say, that if you grasp the facts in this article, you’ll be way ahead of many folks I meet in this industry.

Small Bike Compromise: Sacrifice Bike Weight!

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This is part 5 of 8. Here is the start!
A quick overview of terms that are important:

  • Fork Rake – Offset that places the fork ends ahead of the steering axis
  • Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
  • Trail – The distance that the axle trails the steering axis intersection with the ground
  • Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
  • Reach to Bars – Distance from center of seat to center of handle bar stem
  • Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
  • Seat Tube Angle – The angle of the seat tube in relation to the ground
  • Toe Strike – How much of the foot interferes with turning the front wheel

More detail of a steel fork solution

Compromise 4.) Sacrifice weight:
Let’s go old school, and use a steel fork like in the 1980’s. This is a pretty good option if you really want to use 700c wheels on a smaller bike. We can build a bike just like we used to in the 1980’s, and put lots of rake in the fork to match the slack steering angle to keep the trail number at 60mm. Although the steel fork is heavier than modern carbon forks, the bike will be comfortable to ride and you won’t hit your foot on the wheel when you try to turn. The handling of a bike like this is still not what most people are after on race bikes, as the ‘front center number’ (another article) is more like a 1980’s Peugot, but the bike is safe.

This compromise is the one we recommend for smaller riders wanting big wheels. If you want to feel a bike set up this way in comparison to a 650c wheel bike, just ask and we’ll let you try them both on extended test rides.

Monday: Sacrifice convenience?

Small Bike Compromise: Sacrifice Performance!

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This is part 4 of 8. Here is the start!
A quick overview of terms that are important:

  • Fork Rake – Offset that places the fork ends ahead of the steering axis
  • Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
  • Trail – The distance that the axle trails the steering axis intersection with the ground
  • Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
  • Reach to Bars – Distance from center of seat to center of handle bar stem
  • Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
  • Seat Tube Angle – The angle of the seat tube in relation to the ground
  • Toe Strike – How much of the foot interferes with turning the front wheel

Compromise 3.) Sacrifice performance:
More detail on a slack headtube

If the head tube angle is made very slack, say 68 degrees or less, that will usually be enough to get the 700c wheel out of the way of the foot of most people who need a top tube of less than 53cm, even with a modern carbon fork. “Why not just do that?” you ask? Well, remember ‘trail’? In short, if a bike has a very slack head tube angle, but not enough rake in the fork, the steering is affected in a very negative way. It shoots up to over 100mm on some expensive custom bikes. In other words, you won’t be been doing the ‘look ma, no hands’ trick unless it’s followed by the ‘look ma, no teeth’ trick.

This compromise will result in a bike that handles like a 1966 Ford pickup with no power steering. The bike will be hard to control in tight corners, and just not as much fun as it should be. Having to put so much energy into steering creates pains in the neck, hands, shoulders, and arms. This is all the opposite of what Rodriguez philosophy of cycling is about.

Tomorrow: Compromise the weight of your bike?
Read more about it!

Small Bike Compromise: Trickery!

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This is part 3 of 8. Here is the start!
A quick overview of terms that are important:

  • Fork Rake – Offset that places the fork ends ahead of the steering axis
  • Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
  • Trail – The distance that the axle trails the steering axis intersection with the ground
  • Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
  • Reach to Bars – Distance from center of seat to center of handle bar stem
  • Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
  • Seat Tube Angle – The angle of the seat tube in relation to the ground
  • Toe Strike – How much of the foot interferes with turning the front wheel

More detail of drastic frame changes

Compromise 2.) Resort to Trickery:
Here’s a tricky one. If a bike has a modern carbon fork, a 70 degree head tube angle, a top tube length of 50cm, no toe strike, fairly decent trail of 79mm, and 700c wheels, has the company found the magic formula? No. They have artificially shortened the top tube by making the seat tube angle really steep. What does this mean for the rider? Really sore knees, or the seat pushed all the way back on the rails in order to get the knees in the right pedaling position. Once the seat is pushed back on the rails to accommodate for thigh length, the reach to the bars becomes the same as if the top tube were 53 or 54cm, and the rider is just as uncomfortable. Why do this at all? To list a 50cm top tube in the catalog. Many, many manufacturers pull this stunt. I call this misleading 🙁

Result – This one’s really not a compromise at all. You just end up with a bad fit, and bad design. Same as Really bad option number 1 with a little knee pain thrown in as an extra treat. Discomfort and pain always results in slower riding, and that’s one thing that everyone can agree on.

Important Note: Make absolutely sure that your salesperson uses a plumb line on your knee to ensure proper knee alignment. If they don’t use a plumb line, then leave without purchasing the bike as you are not dealing with an experienced bicycle fitter. If the bike you are riding has an extremely steep seat angle, chances are you’ll need a lot of attention to your knee position. I strongly recommend several rides before committing to a bike with a steep seat angle. A 15 minute test ride will not be long enough for any knee issues to arise.

Tomorrow: Do you want to Sacrifice Performance?
Find out Here!

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Small Bike Compromise: Wipe-Out!

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This is part 2 of 8. Here is the start!
A quick overview of terms that are important:

  • Fork Rake – Offset that places the fork ends ahead of the steering axis
  • Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
  • Trail – The distance that the axle trails the steering axis intersection with the ground
  • Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
  • Reach to Bars – Distance from center of seat to center of handle bar stem
  • Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
  • Seat Tube Angle – The angle of the seat tube in relation to the ground
  • Toe Strike – How much of the foot interferes with turning the front wheel

Wipe-Out!
More detail of Toe Overlap
Compromise 1.) I call this one Wipe-out
Believe it or not, there are manufacturers that say ‘toe-strike’ is not an issue. So, they just build the small bikes to the same handling characteristics as the large bikes. 60mm of trail, 72 degree head tube angle, 40 ~ 45mm or fork rake, 73.5 degree seat angle, 50cm top tube, and toes be dammed. Massive toe strike like the photo shown above in this article is common place with some major race bike manufacturers.

This picture is one I took when the customer brought the bike in because of crash damage. He didn’t know why he crashed, he only know that he had swerved to miss a car door that was opened suddenly in front of him. I’ll bet you can figure out how he crashed. We quit offering bikes built with massive toe-strike because of our money back guarantee. So many people who thought it would be fine, decided that they were not fine with a lot of toe strike and returned the bicycle to us for a complete refund. Nothing speeds up design upgrades like a money back guarantee I’ll tell you!

I urge you to check any bike that you are considering purchasing for acceptable level of toe-strike before you buy it. A 15 minute test ride won’t do either. If you’re going to accept a bunch of toe-strike, you should ride the bike on your regular route a few times before you buy it. As far as I know, we are the only manufacturer who will buy back a bike that the customer is not satisfied with. With most manufacturers, you bought it, it’s yours! There are a lot of women and shorter riders out there that have listed a bike on Craigslist after discovering that they were afraid to ride it because of toe-strike.

Tomorrow: Would manufacturers resort to Trickery?
Find out here!

650c vs 700c

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Today’s subject: 650c vs. 700c wheels on smaller bikes

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Find wider 650c tires at
650biketires.com

See photo galleries of 650c bikes at www.rodbikes.com

A quick word about wheel size: 650c is a smaller size than 700c. It’s a not a huge amount (We get into that in a few days) but it’s certainly visually noticeable when next to each other.

This is a series of eight articles that we’ve put together to explain the challenges that bicycle manufacturers face when building bicycles for petite cyclist with big wheels. It should put to rest several myths by educating you in the area of bicycle geometry as it relates to fit, safety, handling and practicality. These articles may seem basic to those in the industry, but are written for those not in the industry. Over the next several days, we will post, one at a time, the series. Thanks for reading, and I hope the information is helpful for any petite cyclists out there that are being bombarded with conflicting advice.
Now on to the overview and reasons for the series.

The quick overview of this series for those who don’t need massive amounts of info

Although they can be made to look normal, 700c wheels on a small bike always results in one or more unavoidable compromises.

Although 650c wheels allow us to design a smaller bike to handle great and fit comfortably, they do result in a few compromises.

Obviously if there were no downside to 700c on every bike, then that’s all we would offer. But, there are several drawbacks, and that’s why we offer 650c wheels as an option for smaller bikes.

Now, maybe you want to really understand the subject before you commit? Maybe you’re the type that needs to arm yourself with some technical facts before you brave the conversation with ‘the bike expert’. For those of you who really want to have a grasp on the subject, I’ve written more….a lot more.

Who this series is for:

  1. Anyone who is under 5′ 5″ tall (especially women), has long legs, and is shopping for a bicycle.
  2. Anyone who is advising someone who is under 5′ 5″ tall about bicycles and what to look for when selecting the proper size.
  3. Anyone who likes to read nitty gritty details from the mind of a crazed bicycle frame designer who’s spent his entire adult life designing bicycles.

Terms you’ll want to understand for this series:

  • Fork Rake – Offset that places the fork ends ahead of the steering axis
  • Head Tube Angle – The angle that the frame holds the fork at in relation to the ground (same as steering angle)
  • Trail – The distance that the axle trails the steering axis intersection with the ground
  • Effective Top Tube Length – The measurement from the center of the seat post to the center of the head tube when measured level
  • Reach to Bars – Distance from center of seat to center of handle bar stem
  • Proper Knee Alignment – Adjustment to ensure that your knee is centered over the pedal spindle
  • Seat Tube Angle – The angle of the seat tube in relation to the ground
  • Toe Strike – How much of the foot interferes with turning the front wheel
Disclaimer: I’m not trying to sell anyone on a specific wheel size. Realize as you read this series, we are happy to build any size bike with any size wheel. I just want to show why we offer smaller wheels for those who need smaller bikes. We build small bikes with 700c wheels all the time as some people are willing to accept the performance compromises that are unavoidable.

Bike Industry Misinformation
There is a lot of misinformation that is spread throughout the cycling industry about bigger wheels and smaller wheels. There are reasons for this, but this article is about why we do what we do. If you want to delve further into the misinformation I go into that here. For those that have already heard it, and just want to get educated on the subject, read on.

Oh yeah, if someone at a bike shop tells you that 650c wheels are slow (it happens all the time), ask them if you can test ride one of their slow 650c wheel bikes to see for yourself. Chances are, they don’t have any, and probably have never even ridden one. Why would they have ridden a 650 bike if they are over 5’4″ tall? If you’ve been told this, and want to read more on the subject, that’s here.

Why Compromise? Well, sometimes you just have to.

If you ride a modern bicycle with a top tube shorter than 54cm, and the wheel size is 700c, you’re already compromising. This series is to inform you of the compromises that are made throughout the bicycle industry when designing bicycles for riders under 5′ 5″. It is very technical, and ventures into eye glazing geometries. If you read it well, and understand it, you will be more educated in the subject of bicycle design than most folks who actually work in the bicycle industry. My goal is to help the more petite cyclists among us make an educated decision based on physics and truth. Along the way, I’ve linked to some information that will dispel the myths that have been regurgitated for years in bike shops and magazine articles.

A stock frame from another company with 2 inches of toe overlap

Example of toe strike on smaller race bike

A Rodriguez built for the same size rider, with no toe overlap

Example of same size bike with no to strike

So, why do some bike manufactures suggest smaller wheels on smaller bikes?
Short answer: Because they want to offer the petite rider the same performance and comfort as they do the taller rider. It all boils down to something called Toe Overlap or Toe Strike:

If your front wheel overlaps and hits your foot when you turn, this is called ‘toe strike’. The smaller a frame becomes, the closer the front wheel gets to the rider’s foot. A small amount (maybe 1/4″ or so) of ‘toe strike’ can be common on modern race bikes, but more than 1/4″ can be quite a nuisance, or even dangerous, especially if the rider wants to use fenders.

Good Design
A smaller wheel allows us to produce a shorter reach frame with the proper head tube angle for good control while at the same time minimizing any, if not all, toe strike. Using a 700c wheel on a bike with an effective top tube of less than 53cm requires design gymnastics (or in some cases, cheating a little) to keep this from happening. Design gymnastics result in improperly fitted bikes, or bikes that handle poorly.


In the 1980’s smaller high performance bikes had 700c wheels. What happened to those good designs?

The Carbon Age – Now that carbon forks are the norm on just about all competition bikes, they must be purchased from manufacturers who do not offer products with rakes required to accommodate really slack head tube angles. If we could custom make carbon forks one at a time, the way we used to make steel forks, then we could pull this off, and our jobs would be easier.

Trail Mix
Something that most people don’t realize (including many who work in bike shops), is that there are good reasons for the head tube (steering) angle and fork rake as they relate to the handling characteristics of your bicycle. They are entwined with each other, and when one changes, so must the other. The trail number is dependent upon the combination of the two, and ignoring it will result in a bicycle that doesn’t handle properly. The desired trail number for most purposes is 60mm or somewhere very close to it.

If you want to have some real fun, ask your bicycle salesperson “what’s the trail on this bike?”. It’s a good way to determine the experience level of your salesperson.

Why did steel work better?
Steel forks offer much more flexibility for bicycle design. Years ago (1990 and before), we built lots of small bikes with 700c wheels and steel forks. We could change the head tube angle to a more ‘slack’ degree to move the wheel further out in front of the rider and then build the fork with more ‘rake’ to accommodate proper handling. The more ‘slack’ the head tube angle, the more ‘rake’ is required in the fork to maintain the appropriate ‘trail’ number of 60mm. The added rake moved the wheel out even further.

The very best way to put a 700c wheel on a smaller bike in 2012 is the same way that we used to do it in the 1970’s and 1980’s…..use a steel fork. By using a steel fork, we can keep the handling characteristics acceptable, and still build to the proper fit and knee angle.


The things I’ve seen:
Smaller bikes with 700c wheels and modern carbon forks have been made by many manufacturers, and I’ve probably seen them all in the repair shop. The compromises used are many. Here’s a list of the compromised designs I’ve seen:

Really bad option: No compromise, completely ignore proportions
Some manufacturers don’t even pretend. They simply make the small frames with a 54cm top tube, just like their bigger frames. So the reach to the handlebars for a 5′ tall rider is the same as the 5’8″ rider. Many women have ridden this way most of their lives, and they think bicycles just have to be uncomfortable.

I actually appreciate this approach simply because it doesn’t pretend to be something it’s not. This will provide the proper stand-over height, but a shorter rider’s reach to the bars will be a long trip and a very uncomfortable ride (sore neck, back, arms, shoulders, etc.). Many shorter riders know what I’m talking about as they’ve never been offered a proper fitting bicycle for most of their life.

Now, if you’re of smaller stature or need a top tube length less than 54cm, and you want your bike to fit right, there’s a number of compromises that you can choose from. Some of these compromises are much better than the others, and some are meant to fool you.

Tomorrow’s article:
Wipe-out! Some manufacturers are building dangerous bikes for their petite cyclists.

Click here to continue your study.

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