Special Snowflake cyclocross sizing question

This is very specific to me and my current predicament, but I’m looking for some advice/guidance. My trusty 2015 crux frame finally needs to be retired, and I’ve more or less settled on the latest Trek Crockett through my LBS, frameset only because I can move everything over from my crux (aside from wheels).

I’ve raced a 54cm crux for 6 years, it’s all I’ve ever ridden for cx. My road bike is a slammed 56cm caad12 with 120mm stem. The 54 Crockett is slightly smaller and lower stack than my 54 Crux, which is already a size smaller than my road bike. The 56 Crockett would be noticeably bigger with a higher front end.

I’m 5’10”, 175 lbs.

Does the hive mind still (somewhat) recommend sizing down for CX, or is it different with the latest geometries? I’m leaning towards the 56 Crockett.

I don’t believe the hive mind has recommended sizing down for cyclocross bikes for quite a few years now.


This idea of sizing is designed for roadies buying their first cx bike. You have ridden a dedicated cx bike for 6 years so you know what sizing is right for you. Assuming the crux is how you like it, compare the geometry with the crockett and choose the crockett size that’s as close to your crux as possible, then use headset spacers/stem length to (almost) perfectly match your position from the crux.


Do you have the ability to test both? I believe the boone is identical geo? Might be easier to find that in stock to try. Do you have a shop that would let you play with different stems/setups?

For comparison, in 6’2”, 33ish inseam. I ride a 58 boone. Test rode a 56 and felt like a child’s bike to me.

Just to throw an option out there, is a used bike an option for you? I think the Crux went gravel after 2020, so if you can find any 20s, I bet it would feel right at home for you

In my mind the only way to find out is to test ride both sizes. Importantly, do not simply do a quick ride around the block, ideally you’d want to have the bike for a weekend or a week.

When I switched from my first 26" mountain bike to my first 29" mountain bike, for the first day-and-a-half, I felt like wearing clown shoes. But then the feeling normalized and now my 29" hardtail feels great and natural.

From your post I cannot make out whether you are someone for whom both sizes can work or whether you simply have been riding the wrong size for a few years. On paper, size 54 cm should work for me. But I have ridden >10 drop bar bikes from 3T, BMC, Cannondale, Trek, Felt, etc. in sizes 54 cm/M, and they all felt too small to me. When I tried 56 cm/L, it felt spot on. The reasons seems to be that I have longer-than-average limbs, which makes me feel crammed on a 54 cm.

Have you had a look at what you have, compared it against:

Look at your crux and then use:
Calculate the stem size for your cockpit setup (bestbikeadvice.com)

Try and have your cx bike have a 100-110mm stem. this is what they are designed for in terms of dynamics. dont have silly negative stems or heaps of stack.

This is if you are happy with crux position i guess.

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If you can make the smaller one work for you, I’d get the smaller size. Shorter wheelbase = better cornering. However, toe overlap might be more of an issue on a smaller frame.

This is the comparison tool I used to get to the realization that my 54 crux is between the 54 and 56 Crockett, though closer to the 54.

My 54 Crux has always felt small in the “nimble and agile” way, I like it but it is also the only cx bike I’ve raced on. I worry that anything smaller, like the 54 Crockett, would actually feel too small in the wrong ways.

Unfortunately I don’t have access to one of each (or either) to test ride, though, if I hate the one I get the LBS will take it back, we have a good relationship.

Used is an option but obviously limited to what’s out there.

Thanks for all of the input, everyone!

Sounds like you dont have a trek shop nearby? It may be worth it to find the closest one. They offer 30 day return if it doesn’t work out for you

The LBS is a Trek dealer, they just don’t have any cx bikes in stock, unfortunately.

When I was buying my boone, I was between 56 and 58. They only had 58 in stock but it was trivial for them to get a 56 shipped in to try.

Is it a trek dealer or a trek store? Mine is a full-on trek store so that may be why it was so easy

This is a local chain of 3 stores that carry Trek. I haven’t explicitly asked them to order one just for me to check out, so it’s not like they’ve said they wouldn’t do it. I just think it sets up an awkward situation if I order a frameset, build it up, and then decide I don’t like it.

If I were spending much more money on a full bike, I’d request that they get ahold of one for me to demo before buying.

I feel pretty confident about ordering the 56 Crockett right now.