Drivetrain skippage

[stewpend0us]

So i've got a new bike with a try-all front free wheel and new drivetrain (i can get more details tonight if needed). To me it feels like the chain is skipping a tooth or something but i'm not sure.

Would the difference between chain slippage and the free wheel skipping be obvious?

Do I just need to let the new parts break in or is there something wrong here?

It has a tensioner which doesn't keep super tight tension...I was thinking about making the chain a link or two shorter to try and get some better tension....think this will help?

Thanks!

[stb222]

Chain skipping would most likely happen with a loud popping noise. Freewheel slippage would either be a small griding noise from the freewheel or slient.

[dylan]

when my chain was too long, the tensioner held it at too big of an angle in the rear. meaning that not enough teeth where making contact, and the chain slipped over them. i just took one more link out and now it's perfect.

[va_tick]

what cog and chain are you using?

[stewpend0us]

what cog and chain are you using?

I can let you know later on tonight...

I think i'm going to start by shortening the chain one link and see if that helps. It's not exactly a loud pop but it's not grinding and it's not quiet so i think (hope) it's just the slack in the chain/not enough engagement on the gear...

[MIKE1968]

make sure there is no chain suck or stiff links, make sure that its completely straight chain line (this one is a biggie!) ..A big clink can be the freewheel...

[stewpend0us]

You think i should be worried about the freewheel? it's new only got 5 hours maybe? the clinking started out the box basically.

this typically happens going up a small hill usually when i'm left foor forward which is wierd..could the combination of frame flex when i'm left foot forward and a not straight chain line cause it to skip a tooth like this???

....i'll check the chainline and tension tonight.

What's chain suck?

Thanks for the help!

[Giant1118]

every point has been covered

-chain is straight
-no stiff links
-chain is as short as it can possibly be

knowing the chain and cog may help because there can be some incompatibility issues. ie kool + surly

[stewpend0us]

it's very predictable so here's some pictures taken from a video of it in action...

http://www.observedtrials.net/otn3/skippage 1.jpg

http://www.observedtrials.net/otn3/skippage 2.jpg

http://www.observedtrials.net/otn3/skippage 3.jpg

http://www.observedtrials.net/otn3/skippage 4.jpg

I'm going to see if messing with the tensioner alignment will be enough then shorten the chain which will involve changing the tensioner somehow..

it's a ZHI cog and a KMC chain both brand new no stiff links, seems pretty streight

[aki]

Hmm not sure if it's not compatible or what but I've seen it with random cog & KMC before. Ended up switching to SRAM 9-speed chain and stuck ever since.

If shortening the chain doesn't work you may need to just get another cog or a different chain.

[stewpend0us]

Hmm not sure if it's not compatible or what but I've seen it with random cog & KMC before. Ended up switching to SRAM 9-speed chain and stuck ever since.

If shortening the chain doesn't work you may need to just get another cog or a different chain.

If the chain and cog were a bad match wouldn't it generally suck all the time? this is fine usually but slips after edit:1/4 to 1/2 turn with some pressure (so maybe it sucks a lot but i'm just learning rear wheel hop so i don't notice it a lot yet...)

I think i'll start a new thread asking what cog people run with their kmc though...Thanks

[CriPPle]

Personally I've found that chain skippage over rear pinion feels 'less direct' than freewheel skippage (in terms of feedback felt at the pedals)

Also chain skip makes the cranks jump by a fixed amount every time, whereas freewheel skip varies

Some chain/tooth combos just don't get along, plus if it's skipped under load a few times it's probably ground down your teeth abit so a different chain might have the same problem

[stocktrials]

what tensioner...

[stewpend0us]

godspeed. not a whole crap ton of tension

[va_tick]

I run a 18th eno up front and a echo16th cog in the rear with kmc chain and I have had little to no problems since I've used this setup.......the pics make it look like the chain and cog may not be compatible with each other......its so hard to say though?

[stewpend0us]

I think it's the cog too as the corners of the teeth have already worn off slightly and it seems to be getting worse...getting a new one sent to me, we'll see how it goes.