Quantcast

New to 3 piece cranks, a few questions.

AtTheGates

Monkey
Mar 5, 2003
259
0
I recently purchased a specialized P.1. The bike came stock with specialized fuse 3pc. cranks and chainwheel. I believe these are also sold under the redline, poverty and mosh brand. The chainwheel, out of the box, had a lot of "wobble" as it spins. this isn't causing my chain to fall off, but there is a noticeable change in chain tension. Nothing appears to be loose. Is this common with 3pc. set up? Can I do anything w/o buying new cranks/chainwheel to fix this?
 

ZHendo

Turbo Monkey
Oct 29, 2006
1,661
147
PNW
you should really take off the cranks and tighten the bolt that fixes the chainring to the crank arm. it certainly isn't normal for anything to wobble.
 

AtTheGates

Monkey
Mar 5, 2003
259
0
you should really take off the cranks and tighten the bolt that fixes the chainring to the crank arm. it certainly isn't normal for anything to wobble.
Maybe I was unclear. the chainwheel does not have play. It's not "true" as if it's not sitting flush or is warped. I have disassembled the crankset, checked the bolts and reassembled, every thing was tight.
 

Stoked

Turbo Monkey
Nov 28, 2004
1,809
1
LI, NY
i'm guessing if it was stock out of the box, the chain wheel seems to be defective. is it just the chain wheel that has a wobble or do the cranks have some play?

is the small spacer behind the chain wheel installed?

take the chain wheel back off and lay it on a flat surface.
 

AtTheGates

Monkey
Mar 5, 2003
259
0
i'm guessing if it was stock out of the box, the chain wheel seems to be defective. is it just the chain wheel that has a wobble or do the cranks have some play?

is the small spacer behind the chain wheel installed?

take the chain wheel back off and lay it on a flat surface.
The BB and Arms don't have play. I will have to look to see about the spacer. What does the spacer look like? should it be the same as the ones on the BB spindle, between the cups and arms or is it something like this. My guess is that the chainwheel is warped. I'm assuming this is pretty common with cheap ones.
 

ThePriceSeliger

Mushhead
Mar 31, 2004
4,860
0
Denver, Colorado
I have had them do that before. I was given a new, out of the box Seasons 25t chainwheel from a factory rider and it was so messed up when my right crank was forward it was super tight to the point where the chain wanted to snap, but when my right crank was back, the chain would almost fall off.

It's not completly uncommon. Just get a new chainwheel.
 

AtTheGates

Monkey
Mar 5, 2003
259
0
I have had them do that before. I was given a new, out of the box Seasons 25t chainwheel from a factory rider and it was so messed up when my right crank was forward it was super tight to the point where the chain wanted to snap, but when my right crank was back, the chain would almost fall off.

It's not completly uncommon. Just get a new chainwheel.
I will probably end up with a Tree (they're local) at some point. Being unfamiliar with these cranks I want make sure I'm doing everything right. I don't want to drop coin on a nice chainwheel and have the same problem. Then find that I needed to face the surface of the crank or something else really simple.

Thanks for the help guys
 

sittingduck

Turbo Monkey
Jun 22, 2007
1,958
2
Oregon
If you are talking about side to side wobble, you could probably straighten it. Like a bent rotor, you can tweak it back.
If it's out of round, it's either machined sloppily, or there is too much play in the hole between the chainring and spindle. And/or the spacer that might be there.
I like to machine my own spacers with really tight tolerances, this eliminates a LOT of the tight-spot-in-the-chain issues.
 

DirtBag

Monkey
Feb 1, 2006
648
0
Just about every non-splined chainring will have a tight spot somewhere. You can play around with the location slightly and usually get most of it out.

Are Fuse cranks 19mm Profile-splined? If so get a Tree splined and the tight spot is no longer an issue. If not, just get a new Tree insplined as they are much beter quality.
 

Stoked

Turbo Monkey
Nov 28, 2004
1,809
1
LI, NY
The BB and Arms don't have play. I will have to look to see about the spacer. What does the spacer look like? should it be the same as the ones on the BB spindle, between the cups and arms or is it something like this. My guess is that the chainwheel is warped. I'm assuming this is pretty common with cheap ones.
the thin spacer on the right is what i mean.

 

chuffer

Turbo Monkey
Sep 2, 2004
1,528
869
McMinnville, OR
As already mentioned, that behavior is not uncommon especially if there is an adapter to bring the sprocket hole diameter down to 19mm.

solution: spring for a higher quality sprocket and make sure you get one that fits your spindle without using a spacer...