[berry79]

I'm getting ready to order a new crankset for my 2010 hardrock, but have one last question before placing my order. My stock crankset is a square taper suntor with a chainline of 47.5mm. The new crankset I'm interested in, is the race face evolve xc which has an adjustable chainline of 49mm,50mm,and 51mm. Will installing the new crank with the spacers set for a 49mm chainline work with a bike that is currently set up witht a 47.5mm chainline? Thanks for any help.

 

[mtnbiker72]

Current external bearing triple MTB cranksets run ~50mm chainlines, they work fine even though they are not the ideal 47.5mm.

 

[berry79]

Thanks for the verification.

 

[safme]

You might have to change the front dérailleur as well. When I changed out my crank on my 2009 hardrock FC-M191 to a Deore Hollowtech 2, the dérailleur cage rubbed against the middle ring on my new crank when set to the correct height on the 44mm toothed ring. Also, front dérailleurs are designed for different chain lines. So going from a 47.5 to 50 may require a change if there is not enough adjustment on the one you have.

 

[safme]

Forgot to mention that the large ring on the original crank was 42 tooth.

 

[rlouder]

What do you hope to achieve by changing the cranks?

Most people advise that it's almost always better to just save up for a better bike instead of upgrading components. Besides, there are other more worthwhile upgrades besides the crankset. At least consider waiting until you get some wear on it.

Go out and enjoy your bike.

 

[berry79]

What do you hope to achieve by changing the cranks?

Most people advise that it's almost always better to just save up for a better bike instead of upgrading components. Besides, there are other more worthwhile upgrades besides the crankset. At least consider waiting until you get some wear on it.

Go out and enjoy your bike.

Maybe a little bit of weight savings. My BB was making noise early on and I had it readjusted by the LBS were I bought the bike. It then came back and was the chain which was also fixed by the LBS. Now was again I have a noise even when free wheeling backwards. I now this bike came with a cheap BB and crankset, so I figured instead of just replacing the BB, I'd go ahead and replace everything. Plus this gives me the opportunity to learn how to wrench on the bike. Eventually I plan on buying another frame and swapping the upgraded components to it and turning this one back to stock. I will then have a loaner, spare or commuter and a separate dedicated trail bike. Plus I seem to have the upgrade-itis with everything I own. So even if I started with a better bike, I'd still be switching stuff out. I know it's not the best option financially, but this way I can also spread out the cost.

 

[safme]

Plus I seem to have the upgrade-itis with everything I own. So even if I started with a better bike, I'd still be switching stuff out. I know it's not the best option financially, but this way I can also spread out the cost.

Good to hear there are others out there like me! Do what makes you smile!

 

[berry79]

I have another question about the front dérailleur. I'm replacing mine due to the fact that the stock unit is for a 42T crank and my new crank set is 44T. My question is while shopping on-line I see some dérailleur specs show a chain line measurement and some do not. On the ones that don't, do they work at various chain lines? Second, if I were to order one that does show a chain line spec of 50mm, would it be best to set my new crank set at 50mm even the the factory unit is 48mm? I'm using a race face evolve crank set with chain line adjust ability of 49/50/51. Thanks for any help.

 

[rlouder]

You will likely notice no difference between 49, 50, 51.

Your present der. should work fine on a 44t ring, if it can reach the outer ring.

You can adjust the front der. to different chain lines - up to the limits of the limit screws. Guess that's why they call them "limit screws".

You should be able to determine whether your present der. will work by measuring. With the der. on the large ring, pull the der outwards so the limit screw is stopping its movement. Measure the distance between the edge of the seat post and the outer chain guide. Now back out the limit screw all the way. Repeat the measurement. If the difference between the two measurements is greater than 1.5 mm, then you can use the der with a 49mm chain line, greater than 2.5 mm you can do 50 mm....

You can get the specs from shimano.com to be sure. Anything better than alivio will work at 50. I recently picked up a new LX for 13 (shipped) from ebay. At those prices it, it hardly seems worthwhile to look at cheaper ones.

 

[berry79]

Thanks for the help rlouder. The stock one actually is a alivio. When I looked up the specs it states that it's for a 42T chain ring. This is why I was under the impression it wouldn't work with the new 44T. I figured I could get a decent dérailleur for less than $35 that would out perform the alivio.

I was actually looking at this one
http://www.pricepoint.com/detail/18.../Sram-X.9-Front-Derailleur-Low-Clamp-2009.htm

 

[rlouder]

I used the stock alivio der. on my forge with 44t. It works fine. The upgrade to a lx der. from alivio was noticeable, but upgrading my shifters was a more noticeable upgrade (deore to xt).

These parts are much cheaper on ebay, especially during the winter. You may want to just watch for deals since you can use your present one, as is.

990 front ders. on ebay

http://sporting-goods.shop.ebay.com...s&_sticky=1&_trksid=p3286.c0.m14&_sop=1&_sc=1

 

[berry79]

Sounds good, thanks again rlouder.