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Technical FAQ: Bike-fitting advice from some of the top names in the field

In Tech FAQ, Lennard Zinn employs Andy Pruitt and others to address a reader question on foot alignment, and looks at ’cross bike geometry

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This week we’ll address, at length and with help from a few of the most respected names in the field, one reader’s bike-fit issues that emerged when she needed to replace her shoes. We’ll also take a look at a cyclocross racer’s questions over wheelbase length and choosing a frame when he fits on multiple sizes.

Dear Lennard,
After seven years of wearing the same cycling shoe with minimal kneecap irritation, I am forced to find a new shoe (the other ones are falling apart). Luck has it that I have a narrow, hard-to-fit foot, so my choices are limited.

What I am finding is that the shoes now seem to be tilted inward toward the inner side of the foot. This hurts my knees. Now I am in the world of wedging the cleat (thicker side toward inside of foot). Given that everything else on the bike set up is the same, and cleat rotation is duplicated, is there anything else I am missing?

This new shoe set up has created a cycle of irritation and frustration, with continued discomfort.
— Mary Ann

From bike-fit guru Andy Pruitt:

Changing shoes and cleat set up can be the trickiest part of bike set up. It sounds like you have kneecap tracking issues making the set up even more difficult. My first suggestion is that you not attempt this alone. I would suggest you find the most experienced bike fitter in your region, as they can help look at the whole picture.

Secondly, narrow, low volume feet are difficult, as they are usually quite pronated or flat. All cycling shoes are neutral (non-canted) except for the Specialized, which have 1.5mm of varus built in to the forefoot — lifting slightly under the ball of the foot. The tricky part is that, even with my 40 years of sports medicine experience, I cannot recommend a shoe or any part of its set up without seeing you on and off your bike.

So, again, I would suggest that with your difficult foot design and knee issues you should not attempt setting yourself up without knowledgeable assistance. I suspect you need a combination of shoe-fit, arch, and forefoot considerations and then lastly cleat placement!
Good luck,
Andrew Pruitt, EdD
Founder, Boulder Center for Sports Medicine

From professional bike fitter Charles Van Atta:

The goal in setting up a cycling shoe is to have your knee move relatively vertically during the pedal stroke and in a proper relationship to your foot laterally (side-to-side). As you are experiencing, it is difficult to know that your foot will be held in the same relationship to the pedal as with a previous brand of shoe. In addition to cleat alignment and wedging, the positioning of the cleat front to back in relation to the ball of your foot and the level of arch support provided are important factors.

Ultimately, since there are so many variables involved, seeking the help of a bike fitter with skills to evaluate your body’s alignment and help you achieve a shoe set up that allows for knee tracking that matches your alignment would be recommended. Remember that the physical evaluation, off the bike, may be as important as watching (with the naked eye or through motion capture) what your knees do on the bike.
— Charles A. Van Atta
Cycling Biomechanist, Boulder Center for Sports Medicine

From bike fitter extraordinaire Katrina Vogel:

Finding a cycling shoe for the narrow foot can be tricky. The process can be frustrating and is impacted by many aspects of the foot-pedal interface. The feel of a shoe is directly affected by the cleat/pedal and your individual lower extremity architecture and cycling biomechanics.
There are several questions that need to be asked to accurately assess your situation. What shoe did you use for seven years? What shoes are you currently riding? What pedals do you ride? Are they the same pedals from seven years ago or are they new? Has your training changed at all since you started riding in new shoes?

Based on what we know here are some thoughts.

Any shoe used consistently for seven years will have wear. It is very possible that the shoe itself developed wear-patterns mimicking the architecture and mechanics of your feet and legs. Such patterns may feel “normal” to you but will likely create a structurally compromised shoe. Most shoes wear laterally, resulting in laterally tilted foot, especially in the upper. Thus, when you ride in a new flat shoe, you may feel tilted in because you are not accustomed to the flat sole and the straight upper of the new shoe.

Most brands of cycling shoes have varying heights and widths of the sole. If the sole is slightly wider than your original shoes then your stance width may have effectively increased, thus creating a “kneed-in position.” This can feel like your foot is tilted instead of flat to the pedal and typically results in medial (inside) knee pain. The vertical height of the sole may be higher or lower than your old shoes, thus increasing compression of the patella against the femur; this often times creates diffuse kneecap pain (but not exclusively).

Most importantly, your feet and legs have their own individual architecture, which will affect your cycling biomechanics and pressure patterns within new shoes. Some lower extremity architectures create pressure on the inside of the foot, including a plantar flexed first metatarsal (ball of big toe) and valgus knees (“knock knees”). A bike fitter well educated in the art and science of the foot-pedal interface will be able to identify and work with these architectures and mechanics to address your knee pain. They will work with your shoes and pedals to address fore-aft, stance width, rotation, canting (“wedging”) and, if needed, lifts for a LLD [leg-length difference].

The correct solution will likely include a mixture of the five cleat adaptations to address the feel of the shoes and the knee pain. Over-the-counter inserts may also be of benefit to support your arch. They do not replace wedges but are commonly used together. Do the best you can with the current shoes on the market. The bike fitter will customize the foot-pedal interface to your specific needs.

The role of your pedals cannot be overlooked. Older shoes and pedals allow more foot rock and allow for more motion, thus allowing the foot to sit in its naturally tilted position. In addition, older shoe materials tend to wear more quickly. The combined effect creates more “slop” and float at the foot-pedal interface, which diminishes the sense of how your foot is attached to the pedal. The position of the foot is more noticeable when the foot-pedal interface is tight (as seen in the newer shoes/cleats/pedals). Additionally, width of pedal surfaces is often different between brands and is different even within brands. For example, when Shimano first introduced the wider platform, we received several calls from top pros that said “nothing” had changed but they had outer foot pressure or knee pain. At BikeFit, we deal with a lot of shoes and have fit cyclists in every brand and design on the market. Per our knowledge, no shoe company has consciously created any valgus correction (“tilting in”) of their shoe design. (Unfortunately, a few have inadvertently created it within their shoes due to manufacturing mistakes and lack of QC. That is another story.)

I hope this gives you more insight into your shoe situation. Feel free to contact us with any additional questions or concerns. We’d also be happy to connect you with a BikeFit Pro in your area to specifically address your concerns.
Katrina “Kit” Z. Vogel, MS, DPT

Can you feel a one-degree change in head tube angle, too?

Dear Lennard,
As a tall(er than me) rider, I was hoping you could shed some light on a quandary that keeps me up at night. I am a tallish rider, at 6-foot-3 (BB to saddle 85cm); I am usually on most companies’ largest frames. My current cyclocross bike is a Redline Conquest 58. When looking at Redline’s geometry, it seems like it basically took the 56cm and pushed the angles out on either end (from 73/72 to 72/73 for the 56/58). Obviously, there is no compensation in the fork geometry either (and the 58 is actually shorter wheelbase than the 56). I have found that after two seasons, while I love the bike, I am not very happy with the geometry and am in the market for a new cyclocross bike anyhow.

I know lots of people say “size down your CX bike,” but I don’t subscribe to that. Having owned lots of different CX bikes from the tall Ridley to the low and long Redline, I find it just matters where your contact points end up.

I typically can fit myself pretty comfortably on a 58 or 60 (if they are offered) and end up with the size that fits my setup the best.

For CX I am wondering what your thoughts are on the increase of 1-1.5cm of wheelbase. Our team is moving over to Trek, so am looking at the Boone/Crockett. I really like the geometry, and have test ridden a 58 and like the setup. But I am in the position where a 58 and 60 would fit — the 58 with ~2.5-3cm of spacers under the stem, or the 60 without spacers. The only difference then is essentially the wheelbase increase of 1.5cm (and a 0.3-degree STA change). I guess it hasn’t really seemed to hurt Trebon.

Maybe I am just crazy in thinking I can feel the difference in 72- versus 73-degree HTA, too.

Sorry for the longwinded question, but these things keep us up at night, after all.
— Adam

Dear Adam,
I certainly can tell the difference between a 72- and a 73-degree head tube angle and would greatly prefer the former on a tall cyclocross bike (all three of my personal CX bikes have 72-degree head angles).

Do you mean a 61cm, rather than a 60cm Trek? I don’t believe that a 60cm Trek Boone or Crockett is an option. I would go with the 61cm Trek if I were you, unless you can flip that stem up on the 58cm and avoid 30mm of spacers and the added wheelbase. Note that it will take at least one size longer stem to place the handlebar in the same position when flipped up; I went from a 120mm with spacers to a 140mm flipped up without spacers and ended up with only a couple of millimeters more reach.

If you get more stability, control, comfort, and feel of the bike out of the bigger size, then that trumps a 10-15mm increase in wheelbase. Obviously, wheelbase limits the minimum turning radius possible, and sometimes low-speed 180-degree corners in ’cross require the minimum wheelbase. Of course, if you can wheelie around a 180-degree corner, then the wheelbase will be irrelevant. Not a lot of riders can do that, so a shorter wheelbase is preferable in general, but a longer wheelbase can actually offer a slight stability and tracking advantage on higher-speed sections and in deep sand. Don’t seek a short wheelbase at the expense of tire clearance in the back with too-short chainstays or of bike fit and control in the front with a too-short top tube and/or too-steep head angle.
― Lennard