brianblackheart

okay i screwed up and received my replacement crankset in the mail today. I originally had a 28/38/48 crankset on the bike. I received a 24/32/42 by accident. my rear freewheel is a 14/34 megarange. Can i still use the crankset and if i do what will the difference feel like in my riding?

brianblackheart

sorry i meant 42 32 22 crankset for the new one.

JonathanGennick 

Physically, presuming the bottom-bracket interface is correct, you can run the cranks if you wish. What you will lose is some of your high-end gearing. So if you are commonly pushing your two or three hardest gear combinations, then you might be unhappy.

You also might need to shorten your chain. After installing the crankset, shift into the easiest gear combination (24 tooth ring in front and 34 tooth cog in rear), and see whether you have too much slack for the derailleur to take up.

TomCat_Ford

Depending on the type of riding that you do, that could be a pretty low gearing. Now if you're doing a lot of climbing, off-road riding, etc., it might be OK. But if it were me, I would exchange your new crank for one with similar gearing to your original.

When I went through the drive train on my MTB last year, I went from 22/32/42 to 28/38/48 and I noticed quite a bit of difference.

Bill Kapaun

Your current FDER is curved for the radius of the 48T ring.
They use a different part for the smaller 42-44T rings.
After re-adjusting the FDER, you still may have front shifting "issues". It'll probably still work, but a little less precise.

JonathanGennick 

Bill is correct. I have run into that very issue, and I should have thought of it before my previous post.

Good catch Bill.

brianblackheart

well I just sent back the wrong one and am going to order a new one the correct tooth size that is. One more question is though I know there has been millions of threads about this but i have to ask. I am 5'9' and have a 29" inseam so i have short legs and a long body. My giant sedona is great on height since my body is so long but i was wondering if i would be more comfortable with 170mm crank arms? Currently the arms are 175mm and just thinking i might be better off with a little shorter because of my leg length. any suggestions?

Bill Kapaun

Some of that depends on your age and the condition of your knees.
I'm "probably" a bunch older and have one knee that doesn't have full range of motion.
I pretty much have to use 165MM cranks to stay away from having knee pain or on the ragged edge of having knee pain.
175MM and my cadence drops from 80-85 to 60.

I'll say that 170's aren't too short for you.
Also, make sure your seat is adjusted to the IDEAL height.
A little too low and it's like having overly long cranks.