Author Topic: Advice on wobbly chainring (Read 823 times)

beaglepopper · « **on:** September 20, 2008, 08:54 PM »

After fitting my crank i have noticed that the chainring has a slight wobble when spinning the crank. Will this cause the chain to slip off? Is this a common adjustment problem or is it possible that the ring is bent?

RATTY · « **Reply #1 on:** September 20, 2008, 10:23 PM »

As long as it doesnt throw the chain off, leave it as is, try "adjusting" it with a mallet if need be

beaglepopper · « **Reply #2 on:** September 20, 2008, 10:38 PM »

Cheers

When i get a set of wheels i will give it a road test but i think i'll give the mallet adjustment a miss for now

daz bmx it! · « **Reply #3 on:** September 21, 2008, 01:06 PM »

Should be ok,If its a spider I'd just check that the chainring bolts where seated properly between the ring and spider

moley · « **Reply #4 on:** September 21, 2008, 01:17 PM »

If your chainwheel is not bent and your using a 3 pc crank then this might help.

If your using a crank arm with a screw to hold the chainwheel in place then it could be making it off balance when fully tightened.

Try loosening the screw a bit and see if it spins true.

If it does then you have 2 options.

1 pc cranks are held in place but aren't screwed so leave it as it is. But make sure you have some ptfe on the threads of the screw to make sure it does come loose while riding. This might be problem because your chainwheel although true might have some slack and move backward and forward while you pedal!!

or you might be able to fit a washer between the chainwheel and the arm to take up the slack and to make sure its fully secured and rigid. Also check if your using a reducer to fit the chainwheel. try fitting it with the edge on the inside to bring the chainwheel closer to the crank arm (if you know what I mean)

What crank and chainwheel are you using?

And as Daz says!! Are you using a spider?

beaglepopper · « **Reply #5 on:** September 21, 2008, 03:59 PM »

That was a little bit foreign for me

Im new to the building game & i fitted my crank from a video tutorial & guide on here.

I have a mongoose OPC.

Sugino chainring & spider.

The spider bolts look to be sitting flush, i have also fitted a spacer between the chainwheel & arm.

The crank spins free and smooth so apart from the slight wobble it seems ok.

Im thinking, i may have damaged a bearing cup when putting them in, maybe $:-\$ Im guessing that could cause a slight fluctuation?

moley · « **Reply #6 on:** September 21, 2008, 05:01 PM »

If your using a 1pc crank then make sure your Retaining nut Race is nice and tight.

Sometimes it is hard to get a spanner inbetween the nut and spider to tighten it up properly.

Check your alignment of your chainwheel to the freewheel. Stand behind the freewheel and look along the line of the cogs toward the chainwheel. Because you are using spacer (why?) the alignment of the two cogs might be out of whack and cause some strain on the chainwheel.

Use a straight rule (a piece of wood) or use your eye to look along it. If its in line then that is not your problem!!

You should always try and align the two cogs to give the chain the smoothest movement between the two. If the Chainwheel isn't in line then the chain will be constantly rubbing against one side of the chainwheel and the opposite side of the freewheel due to the diagonal movement of the chain. This could also put undue strain on the chainwheel if its way out of true!!

Check the alignment and see if your spacer is the problem.

If your parts are used then you chainring might be out of whack or a tooth might be bent. Take it off and place on a flat surface and see if its flat. Look down the teeth and see if a tooth is bent.

Post some piccys?