Grinding / vibration / chain tension

Hey all, quick query.

Constantly faffing with my chain tension, yet I always run into the same problem:

As the chain just gets to the right amount of tension, it seems as if it binds slightly on the tight spot on the chainring. This produces a bit of noise / detectable vibration at slow speed.

Its irritating.....

I use a Surly Chain Tug - so getting the chain tension right is pretty easy - yet it still seems to vibrate!

Could it be because I'm running an "odd" rear sprocket (44x17)

Is this the price I have to pay for less tire replacements, or am I a nonce?

Cheers,

Nonce.

How is your chainline?

Check the tension of the chain at various spots in the wheels rotation. Is it getting tight/loose at diff. spots? Are you using shit parts? Are the parts brand new?

There's a definite tight/loose spot - coincides with the cranks getting to the Horizontal position.

Parts wise, it's a 44t 3/32 Bontrager GXP with about 800 miles wear, paired with a Surley 17t 3/32 which has had about 100 miles.

It's a lemond fillmore, chainline wise - visually not an obvious problem, although I haven't measured it like this guy:
http://www.londonfgss.com/thread2592.html

Sort out the tension first then get back to us.

straight answer - your chain need at least half an inch of play, that's when you know your chain tension is spot on

(not as slack as the photo thought).

if your only grinding on your vibrator you doing it worng

Buy a better chainring

I'm having a similar problem actually, the difference in tension at different points in the chainring's rotation is quite alarming. I've just replaced the chainring so now I have Dura Ace (road) ring and Dura Ace sprocket but it still seems impossible to find a position that gives me a high enough tension at the loose spots without binding. Tried the Sheldon spanner tap technique etc

If you move the wheel forward slightly, does the chain become too slack or still grind like you describe?

I think Sheldon's "tight as you can get it without binding" advice is probably the least helpful bit of fixed gear lore out there.

You're better off with "loose as you can without chain drop".

I think Sheldon's "tight as you can get it without binding" advice is probably the least helpful bit of fixed gear lore out there.

You're better off with "loose as you can without chain drop".

I might just be a bit over cautious. My old chainring was terrible and even when it was very tight at one point it was so slack at another point it threw the chain halfway down a fucking massive hill. Made me fairly worried about the chain being too slack. Guess I'll just have to keep adjusting and testing.

If you move the wheel forward slightly, does the chain become too slack or still grind like you describe?

Mine doesn't actually grind, I was referring to the tension issues.

My apologies, you could try taking the chain off and rotating the chainring/cranks a bit before putting the chain back on so the tight spot will have moved.
Do you have another rear sprocket/front chainring you could fit, it might just be a bad combination of components?

No problem, I'm gona rotate the chainring tonight to try and find a better balance. Might just have to cave and get a track chainring!

There! YOU said it! TRACK chainring!!

I had the same problem coz I bought a cheap ring (TA from Condor) and I got the tight/loose/tight thing happening.
Changed my ring for a Miche one (2nd hand and well used) and the problem disappeared completely.
I tried two different rings from condor, and the gy tried to convince me it was my chain . . . .duh!

So, to sum up. Get the best track ring you can afford, slapp it on the best track cranks you can afford, and enjoy perfect chain tension on your bike.

hmhmhm maybe you're right then. i also get those vibrations....and they started as soon as I put a FSA tempo (NOT track, you can mount more chainrings there) chainring. I have a correct chainline but there is no way to get rid of vibrations....by correcting the tensions ... ?! this FSA tempo looks so cheap and rough but the guy at the shop who had to send it to me because of the replacement of the faulty one, said it's about 100 euros ?!? i don't think so actually.

Did you managed to slacked your chain a bit more than your video shown?

you already have your own topic about that.

Ha! mergatron has missed the 7 or so threads all asking about chain tension

MERGE the fuckers

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