PDA

View Full Version : Considering crankset upgrade: SRAM Apex to Force



bluerider
05-29-2012, 12:58 PM
I am considering an upgrade on my Blue Norcross EX by swapping out the 48-34 SRAM Apex crank for a 50-34 SRAM Force crankset. If I do it, I will upgrade the bottom bracket to a BB30 as well since the frame is BB30 ready. I noticed one of the GXP BB bearings appears to be loosening a bit so I need to take it in for service anyway (500 miles on the bike). Is this upgrade worth it or a waste of money? The weight savings would be about 0.5 lbs. However, performance and stiffness wise is it worth the cost? Will the Force be more trouble free?

Thanks in advance.

jabberwocky
05-29-2012, 01:11 PM
I have a sram red crankset on my carbon road bike and an apex on my CX bike. Both are GXP/compact/170mm. I personally notice no difference between them in stiffness or shifting performance. I'm actually very impressed with the apex; aside from being a bit heavy, it performs very well and is quite inexpensive.

Dirt
05-29-2012, 01:17 PM
I've had mixed success with my BB30 cranks. Are you doing the install yourself? I'm a pretty good wrench and it took me a little while to get the bearing preload correct on the BB30 set-up. I went through two bottom brackets pretty quickly because I had too much preload on them. I finally got the setting right and have had no problems (with about 1000 miles on it) since. Fortunately BB30 bottom brackets are not expensive.

Having an experienced shop do this will get rid of the trial and error with bearing preload.

I didn't notice a huge step up in stiffness with the cranks (I went from SRAM Rival with BB30 adapters to SRAM Red with a true BB30 set-up, though I cheaped out on the bottom bracket bearings until I got the preload issue figured out). The lighter weight was appreciated.

Dirt
05-29-2012, 01:21 PM
I will add that I also had durability issues with the BB30 adapters that I was using with the GPX-based cranks. Even the old Rival set-up was not perfect.

I hope that answered the question.

Pete

bluerider
05-29-2012, 01:35 PM
Thanks Dirt,
I was planning to have the cranks installed professionally somewhere (CycleLife or Revolution probably). Not sure what the current problem with the Apex setup is right now but I can see a small amount of threads poking out of the BB shell (maybe the adapters on backing out?). The crankset feels tight and I just did 80 miles on them without problems. However, I know it shouldn't be like that. I know the gearing will be pretty much the same. I would stay with 48T but they don't much Force with 48T chainrings.

Dirt
05-29-2012, 02:09 PM
If the bike is new, this should be something handled under the follow-up service that most shops do on bicycles that they sell. It may just be something that needs a wrench thrown at it, rather than parts replacement. If you bought the bike locally, you might want to let them take a swing at fixing it before plunking down a lot of money on new parts.

Can you take a photo of it to show me what the problem is?

Thanks.

Pete

bluerider
05-29-2012, 02:16 PM
The bike is new but was purchased from a Blue dealer in Golden, CO (got a steal of a dealer on it) so I am on my own for maintenance short of some type of warranty issue. I was considering the upgrade before but now that the Apex needs some TLC I am considering it more strongly. I can take a picture for you tonight once I get home from work.

Dirt
05-29-2012, 02:31 PM
Makes sense.

DaveK
05-29-2012, 03:00 PM
I don't have the massive quads to notice a difference between the stiffness of BB30 and a standard English-threaded BB, nor do I really care too much about the flexibility of BB30 over English threads. I really like my SRAM GXP BB and Force crankset on my road bike - very easy to install, only need one special socket, and it's so simple even I can do it. My BB30 crankset on my cross bike knocks and annoys the crap out of me, but I haven't yet taken the time to figure out how it works. If I bought another bike tomorrow I'd look for something non-BB30. That said, if the bike is already BB30-ready, go nuts.

bluerider
05-29-2012, 06:56 PM
Ok, here are some pictures. Upon further inspection, I don't think there is anything particularly wrong. I can see about the same amount of the bottom bracket cage on both sides. All the dirt I cleaned away made it look worse than it was. I think thats just how its designed. However I will continue monitor it. I also realized how badly my bike needs to be cleaned

The non gear side
http://i117.photobucket.com/albums/o43/rsigworth/DSCF0040.jpg

http://i117.photobucket.com/albums/o43/rsigworth/DSCF0045.jpg

bluerider
05-29-2012, 07:02 PM
The gear side:

http://i117.photobucket.com/albums/o43/rsigworth/DSCF0046.jpg

http://i117.photobucket.com/albums/o43/rsigworth/DSCF0044.jpg

http://i117.photobucket.com/albums/o43/rsigworth/DSCF0042.jpg

http://i117.photobucket.com/albums/o43/rsigworth/DSCF0041.jpg

americancyclo
05-29-2012, 09:54 PM
At the least, you could use some new chain rings. Those are awfully pointy.

Dirt
05-31-2012, 09:38 AM
I honestly don't see anything wrong there. Looks like things are visually okay. Obviously if it is clunking, then it needs to be looked at. You've already got that in the works though, with the new crank/bb.

The rings do appear to be really worn. New cranks will get you new rings. Realize that you may end up changing the chain and cogs if they are similarly worn. Those three tend to live and die together if you don't change your chain often.

bluerider
05-31-2012, 11:36 AM
hmmm...... The chain and rings have 500 miles on them. Maybe its just the picture but I will clean them off and check them further. What is a normal amount of mileage out of a typical ring set?

Dirt
05-31-2012, 12:37 PM
hmmm...... The chain and rings have 500 miles on them. Maybe its just the picture but I will clean them off and check them further. What is a normal amount of mileage out of a typical ring set?
Totally depends. There are so many determining factors that you can't really put a mileage on that. I have some that have lasted many years and 10s of thousands of miles.... Others that have gone in a few thousand.

They may just be dirty. Get a chain wear gauge and keep an eye on how much the chain stretches. If you replace the change when the gauge tells you to, your rings and cogs last 2-3 times as long.