nathand

I bought a used bike with one minor issue - it has a standard 53/39 crankset (130 BCD) and I'd strongly prefer a compact 50/34 (110 BCD). The drivetrain is 10-speed SRAM Red, and it has a PF86 GXP bottom bracket. What would you recommend for replacing it? Not a lot of options on eBay for a matching used Red (or Rival, or Force) crank - I just lost out on one. 10-speed Apex cranks are available, new, at reasonable prices. Is there any advantage, other than weight, to the higher-level cranks? Would I actually notice a 250-300g difference? Would I be better off with a new 11-speed crank, or would shifting performance suffer slightly? I don't really want to replace the bottom bracket too; are there other brands that are compatible with a GXP bottom bracket (other than Truvativ, of course)?

cxwrench

Any 10 or 11 speed road GXP crank will work. Unlikely you will notice any difference in weight at that location on the bike.

Bob the Mech

The reason I would buy a used bike is that it's cheaper than a new one. If I had to replace any component that didn't suit my needs I would replace it with one that was the cheapest ****ioning option. If I had a preference for a perticular brand then that's where I would look. I your case the SRAM Apex GXP Compact 10sp Double Chainset. If you wanted to keep the speced full functionalty of your group set as SRAM intended than that's the way to go. If you want to throw more money at the project, then sure move up to the higher spec chainsets. As a rule problems are solved using the simplest solutions, not the most complicated Would you be better off with a 11 speed crankset...funcunality is pretty much the same...but better off no...due to the extra cost factor. Which makes buying a used bike for a cost benefit slightly redundant...Unless ofcourse this is a piecemeal upgrade then carry on and ignore all of this The other good news is 10- and 11-speed SRAM road components are inter-compatible – meaning you could run a 10-speed SRAM Red rear derailleur with a pair of SRAM 22 shifters...(with an 11 speed casette ofcourse).

woodcraft

I have a Rival GXP crank available (175mm) basically new. I went through the same drill recently, ending up with a Force crank at a modest savings of grams.

I'm in Marin.

Iride01 

Sometimes it's less expensive just to change the cassette. Depends on what gear ratios you need for min and max and which you are normally in for most of your riding.

Don't just change because you heard the term compact crankset being touted as the cure all for everything cycling. They've stopped doing that to a large extent lately.

nathand

I have another road bike with a compact crank, and I've done enough riding on the 53/39 crank to know that for a longer climbing ride I'll want lower gears. I already have an 11-28 in the rear which is the largest the derailleur is rated for, and buying a new cassette plus a new derailleur would cost as much as the Apex crank. Also, I never need a 53/11 combination; I almost never use the 50/11 on my other bikes.

Iride01 

You don't pedal going downhill?

You can get a DR that will allow you up to a 32 or 34 tooth cog. But I don't know what your other specifics are for gearing needs. If you have to have close spacing, I can see that a bail out low ratio won't do.

nathand

We're veering off-topic here, but
I do until I spin out, and at that point I don't need to be going any faster. I enjoy twisty descents more than pure speed on a straight downhill, and try to plan my routes accordingly.

I'm failing to see the advantage of replacing both the rear derailleur and the cassette, when I know I can get the gearing I want - the gearing I already have on another bike - by replacing the crank. It's comparable cost and fewer additional pieces to adjust. I'm already replacing the front derailleur cable so I'll need to reset that anyway, and chances are the chain will be fine as is or at worst I'll remove a link which is better than adding one.

Iride01 

Well it seems you've got me stymied to give you any reason not to. You have thought out the gear ratio stuff enough.

So my thought is why not buy SRAM Red crankset from an online vendor that has new or slightly used 10 speed SRAM Reds? Why pay eBay prices for used stuff that is higher than new stuff at other online vendors?

nathand

Can you provide a link to such a vendor? Ebay is the only place I've found any 10-speed SRAM Red parts. Used 10-speed Red cranks on Ebay are selling for somewhere between new 11-speed Rival and Force cranks.

Phatman

You don't need a 10-speed specific crank. 11-speed will do just fine.

redcon1

I would go with Force and call it a day: Red has a big cost premium for the weight savings, and compact Red cranksets are not readily available IME.

Force 22 Compact