CFl.cyclist

Hi all,

As the title says I am looking to upgrade my compact crank to the standard size but I have a few questions. I have a 2012 Trek madone 2.1 with apex groupset. I have been told by trek that it uses "press-fit" bottom brackets. When upgrading to a new crank, could i get away without having to upgrade the BB? If i did, have to upgrade it (which i'm not against), would it be the SRAM GXP type BB or something different? I'm looking to get the SRAM Force crankset but am unsure which BB compatibility I need to order.

Also, are there other things i would need to upgrade to make it all run smoothly, such as a front derailluer? Or would i just need to move it positing up some to compensate for the larger chain rings. Would i need to resize my chain, or would i be able to swap that over without modification too.

Right now i have the compact crank (50/34) and a 12-25 Ultegra cassette with KMC X10SL chain.

Thanks for the help!

HillRider

I'll ask the usual question; what do you expect to accomplish with this "upgrade"?

JohnDThompson 

The only difference between a "compact" crank and a regular crank is the chainring sizes. Just buy the chainrings you want, get a new chain, and move the front derailleur up enough to clear the new chainring and you should be good.

CFl.cyclist

Shed some weight, have a better quality component and a better gear ratio. I race on this bike and will slowly be upgrading the rest of the components over time due to the fact that i want to stick with an aluminum frame right now for racing.

HillRider

True except typical road double 52 or 53T big chainrings and 42 or 39T small chainrings aren't readily available in 110 mm bcd format and those that are typically don't have the shaped teeth, pins and ramps shifting enhancements.

Toi the OP: would the Force crank really be any lighter than the Apex. Would a change to an 11xXX cassette give you the higher gear you want at less cost?

TrojanHorse

standard cranks tend to be heavier because they have a larger BCD... but if you really want to "upgrade" your crank, go get some older SRAM Red BB30 cranks (I'm assuming your bottom bracket is BB30 but I don't feel like looking it up, you really need to find out first because there are different flavors of press fit bottom brackets). previously used standard cranks tend to be pretty available on fleabay. A lot of people dumped them when the new exogram cranks came out. I got a set of compact red cranks for $200 a year ago, so it's possible to get a good deal.

Another option for you, as mentioned above, is to swap your compact chainrings for a set of mid-compact chainrings. Those are 52x36 and will give you a higher gear selection without requiring a crank swap. praxis makes good aftermarket chainrings, but chainrings alone will run you close to $170. Of course, the hazard with buying used cranks is that the chainrings might be thrashed.

CFl.cyclist

I thought about going that route but i feel that would be just a temporary fix. I think i would rather just upgrade the crank. And i misspoke before, everything is apex on the bike, besides the crank, which is SRAM S150 Crank. This crank comes in at about 980 grams and the Force crank is about 790 grams.

I'm pretty sure the S150 is SRAMs most bottom end crank, which is another reason i would prefer to just upgrade the entire crank rather then just chain rings and/or cassette size.

CFl.cyclist

I have been told by Trek tech support that my bike takes "press-fit" bottom brackets and i believe this is the BB i would have to upgrade with a new Crank, but i am still unsure.

https://www.competitivecyclist.com/pr...52.1733.0.html

fietsbob

3rd party replacement chainrings in 110-53t and 110-39t are made by many companies ,
Including TA in France .. offers a few extra Colors too , exported world wide.

I have a set of 110 Campagnolo MTB 52-42 from in the 80s.. sitting around..

[I swapped down to a 50-40,or 38]

cpach

CFI,
Your Trek bike uses the BB90 bottom bracket standard, that basically allows you to use a Hollowgram or GXP crankset and places the bearings inside the frame instead of outboard. So for Force you'd need the normal GXP version. You should't need to change any other drivetrain components. The BB you linked to is NOT what you need. You should be able to reuse the bearings already in your frame since you should already have a GXP crankset in there.

You could also get mid-compact rings pretty easily (52/36) and save cash for weight savings elsewhere.