If I remember correctly TREK uses a BB90

However I would suggest reaching out to HAWK (no personal use with them as I use ENDURO bottom brackets) as they will know all the ins and outs of their products and can be sure to get you set up
With the correct option for your needs, budget and the right one for the system (cranks) you’re wanting to use.

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ig - @servicecourse_evv

You may want to double check the chainring size. I believe when you use a shorter crank arm the equivalent chainring is smaller. I read an st article along time ago about smaller cranks and proper gearing.

Smaller crank makes your effective gearing harder if tooth count is left the same.

Your crank arm is your lever so think of it like a bolt. When it’s too tight to remove by hand you get a wrench, when it’s too tight for the wrench you get a breaker bar and socket. Longer lever makes it easier to spin the nut/chainring.

This is not to say long is the way to go because it’s certainly not the case especially when it comes to tri/TT bikes. The available space to turn long arms typically isn’t there for most riders.

I would definitely consult with your fitter before making the crank length change as crank length change will also have an impact on seat height, fore/aft which will also impact the set up of the cockpit etc...

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ig - @servicecourse_evv

There aren't a great many 155mm crankarm options out there to choose from, certainly with a 24mm axle.
You don't want to try fitting a 30mm bearing in there, bearing life will be greatly reduced, even if its theoretically possible.

Older Rotor 3d24 were a special order I think. Normally 165 were the shortest reasonably available.

New Rotor Aldhu?? is 24mm and available as a 1x down to 155, but then i'm not sure what direct mount chainrings are about; might struggle to get something bigger than stock.

I currently run 165 with 55T albeit 2X. I could stick to 165 since it works if this offers more flexibility in components.

I was looking at this option actually.

https://www.hawk-racing.com/product/bb90-madone/ Should work for the BB on the Trek.


and unless I'm mistaken


https://rotoramerica.com/collections/road-cranks/products/aldhu-24-spider-mount-crankset-builder-axs-compatible


has a 24mm spindle and a 155mm option with 54T 1X.


Just not sure if I should go with the shimano/FSA or SRAM option on the BB if I chose this crankset.

Rotor works with the Shimano 24mm standard.

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Swimming Workout of the Day:

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2020 National Masters Champion - M50-54 - 50m Butterfly

Cool, thanks. Seems that I have found what I wanted.