I need help with road bike sizing

I’m looking at getting a road bike, and it is still impossible to try something in person. Is there any way to figure out if I will need a shorter stem before buying the bike? I’m looking at the Canyon Ultimate CF SLX 8, and the cockpit has a hefty $400 price tag for for a different size. That’s assuming it will be in stock when the bike is. That evaporates the value. I don’t have much experience with bike fitting and it’s all a bit confusing to me. None of the geometry charts measure from where you sit to where the hands go. Obviously that’s different for each person but it leaves me scratching my head how to figure this out without a bike in front of me. My current gravel bike has a 391mm reach and 100mm stem. The Canyon has a 401mm reach with 110mm stem. None of that takes into account to where I sit relative to the bottom bracket. The head tube and seat tube angles are different compared to my gravel bike, and if I raise or lower them it will also change the reach. But how much will it change the reach :person_shrugging:t3:? Any help or advice would be appreciated. My understanding is you buy a bike in the ballpark and tune the size after. I don’t want to be stuck with a bike that expensive and not be able to ride it comfortably. I don’t trust that a replacement cockpit will be in stock.

I’m looking at other bikes too. I’m not set on a Canyon but there is a lot of value packed in…. Those DT Swiss rims :smiling_face_with_three_hearts:. I’d like to build a Tarmac or an Aethos, but those frames are not in stock and my money won’t stretch as far. I appreciate any input, suggestions, or advise.

If you are unable to test ride the bikes you like then I highly recommend going to a bike fitter so they can find you a perfect bike, size and fit for your riding needs.

Also doesn’t Canyon have a free size replacement? I heard that a few years ago so maybe its changed but its worth contacting them if you are not going to get a bike fit. I’d still recommend a bike fit as its the best upgrade you can do to your existing bike and any in the future too

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I believe 99spokes has a ton of geometry info for most big name brands. Perhaps try there?

Edit: 2023 Canyon Ultimate CF SL 8 – Specs, Comparisons, Reviews – 99 Spokes

Head down and there’s a ton of data. Hope it helps!

I totally agree with getting a bike fit. I have talked with a bike fitter. He doesn’t do a pre bike fit and there is no one else in the area. I can get the bike fit after I purchase, but I’m trying to avoid having to buy expensive parts that may not be available.

My current gravel bike has been fit and I can take measurements off of that. I know I can get a frame size in the ballpark. What I don’t know is if you can determine what size stem length I will need before I get the bike. I did contact Canyon and they weren’t that helpful. One person assured me the correct sized cockpit came with the bike, and the other said I would have to purchase a different cockpit if I needed a different stem length.

Have you asked your bike fitter what size bike you should buy? He or she will know from your measurements what size will suit you and what reach you need or at least give you a ball park number. I wouldn’t rely on what other people have to say unless you know they have experience.

Ill be honest with you and recommend a cheaper bike with parts that you can buy off the shelf at any bike shop. Get any bike with Shimano 105 or equivalent, in carbon or alloy. Its your first road bike, buy something cheaper and then keep it as a winter bike if you ever feel the need to upgrade. If I was you I would get a bike from a local store in the $2500 range then buy a power meter and other parts you need to ensure you a proper bike fit. You will even have money left over to buy bibs, jersey, shoes and maybe a helmet too

From the sound of it, OP already has a fair bit of kit if he’s already got a gravel bike. But if he’s a new rider, this is great advice!

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Yup. Not a new rider, and I have kit for all seasons. I gave away my 22 year old Cannondale and have been riding my gravel bike as a do it all. I miss the responsiveness and handling of a road bike. I don’t need Di2, but I want some thing light, fast, and responsive.

Go to your local shop when there not busy and tell them your situation, you might find a good sales person that will measure you up. Other then that, maybe try find another bike fitter or just risk it. If its the bike you want, its the bike you want. If you can live with maybe paying $400 more for the bike you want then its worth it. If they don’t have it in stock I’m sure you will be fine with a slight discomfort for a few weeks until its in stock. I’m assuming were talking 5-10mm difference anyway and that’s not really going to hinder you

I use https://geometrygeeks.bike/ when comparing different bikes. I’m not sure how well that works out if you’re comparing gravel and road geometries but I reckon all information helps in some way.


I can’t speak to the fit but can speak to Canyon’s return policy. Mr. F and I have 3 Canyons between us and love them. Mr F returned a bike once and it was within their 30 day free trial period so all he had to do was pack it back up and they took it back at no cost and with no questions asked. They also have people available that can help with your sizing questions. Worth trying out IMO.

Sounds to me like I’m better off building my bike. Bike shops tend to have animosity towards Canyon and it’s understandable. I’m understating how much the local shops dislike Canyon in my area. If you bring it up, prepare to be shamed.

I’ve asked some generic fitting questions and they assure me if I buy a bike from them they will make sure it fits. They have a stem swapping program. It’s a great answer if they had inventory, but doesn’t help me towards finding a competitors frame. I saw some other brands get frame inventory in online and I will check that out. Still no Specialized Tarmac’s though :disappointed_relieved:.

If you owned a bike shop you would feel the same way too because Canyon is cutting the middle man (bike shops). However a good bike shop should help regardless of brand but its their business not mine.

You are stressing over a few MM in stem size. You can ride a 80mm stem and a 120mm stem on the same bike. Its just a matter of what position you want to be in, Do you want more upright (shorter stem) or more tucked (longer stem). Shorter is also more twitchy and longer more stable but these are more noticeable in really long or really short stems and changing 10-20mm isn’t changing much rider feel, only position but even if it feels different you get used to it very fast.

Your asking for the perfect stem size and the only one to tell you a perfect size is a bike fitter or you by testing a lot of parts or bikes and even then once you find out yourself you will be happy with a different lengths and you wont find the “perfect” size

Like I said earlier, if your are really stressing that much over this then go find another bike fitter, even if you have to drive/ride a long way for it, any advice over the internet might end with disappointment. If I was set on the Canyon like you are I would take advantage over the 30 day free trial like JennF said and test it out, you have nothing to lose.

Also with the build your own bike option you will need a lot of info on your bike fit and since you don’t have that then building your own bike is going to be a lot harder then changing a stem on a premade

Fit >>> components

Given what you write, I don’t think it is a good idea to buy your bike online. You’ll do much better on a bike that fits you just right than one that has Ultegra rather than 105. E. g. in your post, you don’t even include frame size nor your measurements (height, inseam, arm length). But do not just go by charts. If I did, I’d likely be riding a bike in the wrong size.

I’d do the following: get a professional bike fit. The bike fitter will also help you find a bike that fits you and suits your needs. And I’d test ride a bunch of bikes if you can. Try out +/- 1 size, too, if you can. You’ll likely feel what size fits you best.

Bikes of different makes and models ride quite differently, and what feels better is to some degree personal taste. When I test rode a bunch of bikes, including a Cannondale Supersix as well as bikes from Trek, Cube, 3T, BMC, Fuji, Yonex and a few others, I got a much better idea what I like in a bike and what I don’t. I found the Supersix to be very vanilla, competent, but nothing special. The BMC Teammachine and 3T’s Strada immediately felt special and just right to me. But YMMV.

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The reach figure does take into account the bottom bracket. The reach figure doesn’t change. Look at a geometry chart.

The first problem is that you just don’t have enough experience with road bikes as your last one was 22 years old and you no longer own it. You can’t compare the fit of a gravel bike to a road bike except in the most general way. The end fit of a road bike is more aggressive than a gravel bike. Gravel bikes usually have way more stack height.

The second problem is the integrated cockpit. Every time I have set up a new frame, I’ve always swapped stems and bars to get the right total reach to the shift levers. That is impossible with a mail order one piece cockpit since Canyon doesn’t seem to have an exchange policy. Personally, I’d just stay away from integrated unless you are getting it with full support from the local bike shop. It’s just a lot of trouble IMO.

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I’m sorry, but this is just not true and very bad advice. That isn’t a “few mm”, that is 4 cm and makes a massive difference in fit, comfort and handling.

A few mm is to his original post. I dont think he wants to make a jump that big. He said the bike comes with 110 stem and doesn’t want to change it or does but scared its not in stock. But yes your right 40mm is a big gap and i was exaggerating a bit but for someone who has no idea what to do i was just giving simple advice.

What i mean to say is for him to get a shorter stem for more upright and longer for less upright. As he has no idea what he needs so this is the best advice i can give if he is worried about stem length

I am not a bike fitter and you should take my advice with a grain of salt, however I wouldn’t buy a bike from advice from the internet. Stick with a bike fitter or Canyons recommendations.

If he is trying to replicate his current position from his gravel bike, then the Canyon is going to have ~20mm of extra reach. That also is a lot, IMO…likely too much.

Now, many riders prefer to have a shorter overall reach on their gravel bikes vs their road setups. If the OP is looking to do something similar, then the Canyon me be OK.

I’m still baffled by the fitter who said he doesn’t do pre-bike fits, only fits people after they make their purchase. That is someone who doesn’t understand the role of a good fitter.


I’m going through the same process. Currently on an endurance (H2 fit) bike, shopping for something more racy (H1.5 fit). By height I should be on a 54, by inseam a 56…

Selecting my current bike and adding prospective bikes into geometrygeeks all my picks are ~3cm shorter stack with similar reach. However my LBS had a couple of my picks in stock and the actual front ends are more like 4-5cm lower due to integrated stem angle (with max spacers underneath). Moreover the steerer-to-hoods is also very different. For the same stem length the hoods could be 3cm further based on particular bar and shifters chosen so reach values online are misleading. Then you can have a 0 or 20mm setback on the seatpost which also changes reach.
All this is to say I’d not buy anything without seeing, and preferably riding it first. You really cant go by the numbers.

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The published reach is a frame measurement figure that doesn’t change. The parts you put on the bike don’t change the reach but they do change how you fit on the bike.

Stack and reach allow you to compare two frames.

As noted above, frame reach does not change based on components. Hood reach can and will be affected by your component selection.

Seatpost setback has nothing to do with reach if you keep your (same) saddle in the same position relative to the BB. It may change where the seatpost clamp sits on the rails, but if you keep your saddle the same relative to the BB, it does not affect reach.

As for cockpit componentry, it can have a big impact on hood reach. I was looking at an Emonda earlier this year. Went to the shop to check it out…went out for a test ride and the fit was HORRIBLE, even though the stack and reach numbers were what I was looking for. Left and then called the shop the next day and asked them to slam the stem so I could test ride it again….voila, it was like a new bike. The HB width was still too wide, but I knew I could then make the overall fit work just fine.

If you go to a narrower HB, you can expect to have to use a longer stem and vice versa (assuming you want to keep a similar position).