Category Archives: Bike Fitting

Shifting gears

This is a quick note to let everybody know that Gorge Bike Fitter  will be going on vacation from July 1 to October 1, 2017. My family and I will be going on an extended vanventure. When we do resume operations in October, we will likely be in a new location. Future Gorge Bike Fitter offerings will include Canadian and US locations on the West Coast.

Love to you and special hugs to all of you that have supported Gorge Bike Fitter over the years. We plan to come back, restored and stronger than before.

The Sizer Cycle is Here!! Whoot!!

Image of sizer cycle

So I imagine your thinking, “What’s the big deal?”

I can now, without a doubt, help people choose a bike that will fit them properly sight unseen. That’s a big deal.

Take for instance a woman that came to me because she wanted to buy a specific mountain bike and wanted to make sure it would fit her well. By the sizing charts provided, she was best guess a medium. Well, we mocked up the medium and then mocked up the small and it turned out that the small was a significantly better fit for her.

Or the friend that I recently helped by setting him up on 4 different frame geometries so we could figure out which model of tri bike was likely to fit him best and define his ideal stack and reach numbers. He’s now off cruising Craigslist and EBay to find his best possible bike with confidence.

These are just 2 examples of situations where the Sizer Cycle was invaluable. Don’t forget that I can also help you find out if you might feel better with a shorter crank arm or perhaps a different handlebar and stem set up or…  I can even help you define that perfect custom frame build.

I’m equipped to mock up almost any upright bike including road, cross, touring, mountain, triathlon and time trial.

If you’re interested in a Sizer Cycle fitting please contact me by email at gorgebikefitter at good ol’ gmail.

Cycling and knees – Part 1

 Is cycling good for my knees?

This is one of the most frequent questions I get asked, both in my PT practice and in my work as a bike fitter. I hope to answer it here and in Cycling and knees – Part 2.

First, it’s important to understand what makes joints happy.

We were meant to move!

Movement creates rhythmic compression and decompression of joints that helps to circulate joint fluid, improves the supply of nutrition to cartilage  and provides a stimulus that is important for maintaining cartilage health. But too much compression (particularly if quickly applied) on cartilage that isn’t healthy can increase pain and inflammation.

Knees are made up of two main joints that work together. Your primary weight bearing joint, the tibiofemoral, and your force redirector joint, the patellofemoral.

Knee anatomy insituKnee anatomy

In general, the tibiofemoral joint is really happy on a bike. When pedaling it is being compressed and decompressed regularly at forces much lower than what it has to endure when bearing your body weight. Cycling is excellent for people with arthritis in the tibiofemoral joint portion of the knee as it is essentially non-weight bearing rhythmic motion.

On the other hand, the patellofemoral joint is under the greatest amount of compressive stress when the quadriceps contracts with the knee flexed between about 70 and 100 degrees. It just so happens that is when you get strong quads contraction during the pedal stroke. The stronger the quads contract, the greater the compression. These forces are also increased if the quads are tight. For this reason, many people with patellofemoral issues are often not happy on the bike due to the significant compressive forces through the joint during the pedal stroke. Fortunately there are ways to adjust fit to make the forces through this joint less and decrease pain, like saddle position (height and fore/aft), cleat position, pedal axle length, crank arm length…  Pedaling mechanics are also important and can be addressed with exercise.

Having your bike fit done by a professional who understands joint mechanics and physiology is a great way to address knee pain when cycling.

In subsequent installations, I’ll be talking about the effect of cadence on joint forces. We’ll even talk about the good and bad of singlespeeding and fixie riding.

Happy riding.

Stack and Reach

Like it or not, virtual bike shopping is here to stay. The difficult part for the consumer is finding a way to reasonably compare frames in terms of true size. Since the cycling industry does not have standardized ways to measure frame sizes a 54 cm frame from Felt, does not necessarily equate to a 54 cm frame from Cervelo. This is like the phenomenon where you’re a size S (I wish) in clothing from SheBeest but a size L in Exte Ondo. Heck, a 2012 Trek Madone 6 series has 3 different fit profiles in one size. Using stack and reach has simplified the frame comparison process somewhat but what I hope to explain is why you should not look at stack and reach in isolation when purchasing a road bike.


What are stack and reach?

These measurements reflect the functional height (at the front end) and length of a frame, in that order. They are also referred to as X and Y. Both measurements look at the relative position of the top of the head tube to the center of the bottom bracket, reach (X) is the horizontal measurement, stack (Y) is vertical.

Diagram illustrates stack and reach

Looking at stack and reach is a very simplified way of telling if a bike is in the fit ball park for a person. What it doesn’t take into account is where in those 2 dimensions is your saddle and therefore your bum if you’re seated.

 Looking at stack and reach is a very simplified way of telling if a bike is in the fit ball park for a person.

Why Tube Angles Matter

If I take the same frame that I mocked up in the diagram above and over lay another frame with the same reach and stack but with a steeper seat tube, you can see how the real world reach (distance from the top of the seat post to the top of the head tube) changes. That means that the distance from one’s bum to the hanblebars changes if you are riding seated, which on a road bike, should be most of the time.

Diagram showing how seat tube angles effects fit but not reach and stack.

That change is not insignificant. A 6 cm difference cannot easily be made up for in stem length and saddle position fore and aft without compromising other aspects of fit or bike handling.

So why use stack and reach at all?

The use of stack and reach started being used widely in time trial and triathlon bikes. The advantage was the ease of comparing handlebar height which is of the utmost importance in these riding groups. The lower the handlebars, the more aero you are. Unfortunately, we don’t all possess the flexibility to go as low as  ideal aerodynamics might dictate and we need a higher stack. Since most TT and Tri bikes have the same seat tube angles the whole process could be simplified and frame height would be accounted for by using reach and stack.

The mountain bike industry is also catching on to stack and reach using the argument that feet relative to hands is what’s important for technical riding since much of the time your bum’s not in the saddle anyway. Mountain bikes vary a great deal in tube angles, so again you have a fairly functional simplification that will work more often than not in that arena.

In road biking, stack and reach can be very useful for narrowing your bike search down. Just keep in mind that seat tube (and to a lesser degree, head tube) angles will affect your fit. If tube angles are the same, no problem. If they are different, you need to mentally account for that as you make your decision.


Stack and reach can help you quickly narrow down frame options to those that are within your fitting ball park but these measurements have to be considered in context of stand over and tube angles to truly pick out the right bike for you.