rentilrebo

I am upgrading my DIY road bike with new Shimano parts when I can and the next part I'm looking at is a new crankset. My question is can I use any crankset on my road bike as long as it's triple? Can I use a mountain bike crankset on a road bike?

FBinNY 

Yes, if other factors are matched, but there are complications.

You'll need a matching BB compatible with your crankset. You'll want to match the number of speeds closely because it affects chainring separation, so, for example a 10s chain might snag between the rings when shifting on an 8s mtn crankset. Then you'll definitely want a mtn front derailleur, since the typical road derailleur cage won't go low to clear the chain on the granny. That means that if you have index front shifting, you have to make sure the pull, or cable response ratio is the same (usually is if you stay within the same brand) and that the left shifter has 3 positions. Lastly, the RD has to have enough chain take up capacity for the wider spacing of your new chainrings.

Now if this is part of a long term conversion, you can start with the crankset, and maybe BB, but not using the granny, until other parts are changed to make it fully compatible.

Drew Eckhardt 

As long as you use a bottom bracket which is compatible with the crank and derailleur which is a close enough match for the resulting chainline and ring sizes.

Of course you might not want to. People like having a bigger top gear for road riding, outside of loaded touring people usually don't want a low gear that small, and many people like tighter spacing between gears which is more practical when you start with a 12 or 13 cog that wouldn't be enough with a typical 44 tooth mountain bike big ring where you might prefer an 11.

Ex:

13-14-15-16-17-18-19-21-23-25
12-13-14-15-16-17-19-21-23-25 (no 18)
11-12-13-14-15-17-19-21-23-25 (no 16 or 18)

The mountain crank will also produce a greater chain angle on the bigger cogs.

Kimmo 

Why? What's your current crankset?

Ratios and lengths aside, they're pretty irrelevant to performance; my second road bike started out as a $120 lugged 27" with 6sdp Accushift, and ended up as a carbon shimergo beast, and the one bit of grandpa's axe that didn't change - the Sakae crank arms. They were stiff enough, and looked okay, and significantly better ones very spendy. (Although these days I'd change em for 175s.)

Even if you have a compelling reason for new cranks, like you want to go from double to triple, if you want nice ones I'd go second hand... retailers selling cranksets see you coming, it's ankle-grabbing stuff.

rentilrebo

Here's the crankset I'm referring to.

https://www.nashbar.com/bikes/Product...33_-1___202345

My current crankset is from an old Giant hybrid I bought a few years ago and planned to cannibalize to build my first bike. It is a triple. Since then the only old parts still are the crankset and the canti brakes. And recently the crankset has been grinding a little bit. I figured for that price it would be worth it if it was possible

cny-bikeman

Sigh - now it's a bit more complicated. You don't know if the "crankset" grinding will be fixed with a new one, as it could be the chain or cassette that's grinding. I would advise you to get an in-person assessment of the bike before you spend money fixing the wrong problem.

bradtx

rentilrebo, I know of one hill in Columbus that this is a good idea. Unfortunately none of us are in the same room to determine what the cause of the grinding is. Can you do some testing and let us know? Look at the FD alignment, chain possibly rubbing the stay, BB failing or even the pedals.

Brad

fietsbob

Bike Shop can see what this list [text] cannot.. Drop by..

rentilrebo

I had it in a Bike Source a few weeks ago and they told me there was a grinding in the front gears. I put it up on my stand and it looks to me like the biggest gear is slightly bent out causing the chain to rub the derailleur.