My question is about a retul bike fitting. It is my understanding that the retul fitting bike will help me determine the correct frame size and the rough dimensions I can use to build my bike. Will it also give me useful information about which frame manufacturer to choose? Or is this something where I just need to test ride several bikes to find the best feel for me? In other words, should I consider a bike fitting prior to making the investment in a frame?

I need some help! I am an avid bike commuter. I purchased a Specialized Sirrus 6.0 about 3.5 years ago. I love the sport and I am now in the market for a custom road bike. I have purchased a Dura Ace groupset and a DT Swiss 1100 ERC dicut 45 wheelset.

I bought a Cervelo frameset after a 15 minute test ride. I did so based upon a good finance offer from the bike shop. However, I started having second thoughts and cancelled the order. I want to make sure to order the correct frame and size for this project. Since I am investing over $10K, I don't want to be quick to decide. I am pretty set on an endurance road bike.

2 Answers 2


A bike fit will give you good information about which frame size/geometry to choose, based on your current bike.

For example if the bike fit tells you that you need a 140mm stem for your current bike then obviously your ideal bike should have much more reach. If the bike fit tells you you could/should lower your handlebars but you’ve already removed all stem spacers then your ideal bike should have less stack. If your current bike is already a great fit then your new one should have similar stack and reach numbers.

What a bike fit obviously can’t tell you is how the handling of a new bike (frame) will feel.

It might be able to make some rough guesses for bike fit related things like toe overlap (hitting the front wheel with your toes) or heel strikes if you are using panniers or saddle-to-rear-wheel clearance if you are using a big saddlebag.

Edit: Is this the Retül system where you bring your own bike and they put it on a trainer or is this the one where they have a fully adjustable trainer? I don’t have experience with the latter one, but I’d assume they can make some recommendations for ideal stack and reach as well.


It sounds like you currently have a hybrid, you want to step up to a road bike, and you have not gone for a bike fit yet.

I haven't gone for a Retül fit. In general, a bike fit should get you the parameters you need to adjust a bike to your desired position, and a Retül shouldn't be different. A fitter should be able to suggest changes to your current position - going from a hybrid to an endurance road bike fit would be one example. Many fitters should be able to assess your mobility and suggest exercises or stretches to improve key weaknesses that might affect your riding. Also, you don't need to limit yourself to Retül; you might find that you work better with a different fitter.

It will not tell you which frame manufacturer to choose. You need to determine this yourself. Unless you have unusual physiology, you probably can get an acceptable fit on almost all stock bikes. Frankly, if the paint and other branding elements speak to you and the price is acceptable, that's probably a good enough reason to get a bike from most of the major manufacturers provided you can achieve your desired fit coordinates.

In particular, a bike fit will supply (or you can ask for) a target frame stack and reach figure, which tell you the frame size to target, as well as a handlebar stack and reach figure, which tells you or the shop building the bike where to put the handlebar. For example, you might get your numbers. Then you tell the fitter that you decided on (random example) Ritchey Road Logic frame. The fitter might look at the numbers and say, that should require a 55cm frame with 20mm spacers under the stem and a 120mm stem at -10 degrees, and a zero setback seatpost. Some bike shops might be able to do this as well, but not all may.

That said, how we interact with bikes changes with time. Our bodies age, we lose function in some key areas, our desires change. If you're on the right size frame, you can usually accommodate the changes by changing equipment (e.g. maybe 5 years later you change to a 110mm stem or you raise the stem slightly). But it might be tricky to accommodate the changes - for example, I came to prefer a very forward saddle position early on. This rules out a few stock frames, and it means I need a zero-setback post - but some proprietary posts are expensive to replace. I should point out that people often get follow-up bike fits with time.

I raise this because you are jumping from a hybrid to a top-level endurance road bike. There is nothing inherently wrong with this, and it's your money. I will only point out that it is also an option to get a nice but not top-level endurance road bike, and keep riding and dialing in your position. If you do get a top-level bike, it's probably better to avoid models with integrated cockpits, which can be a lot harder and more expensive if you need to change the handlebar position.

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