I presume that chain tension is supposed to be constant

however on my bareknuckle the chain has tightspot and slackspots

it has always been like this and I have never been able to figure out why

anyone had this problem and know waht to do

Phil BB, sugino 75 cranks, ZEn ring, EAI cog on a Phil hub

Your chainring is not 100% round (concentric?). This is pretty normal. There is a method for rejigging the ring on the spider, to lessen the tight/slack discrepancy, somewhere on Sheldon Brown's site. Not really worth doing though unless you're getting near-bind at one spot, and near-dechain at another.

^^^^beat me to it...

Aren't a lot of rings slightly oval?
When tightening the tension, I read somewhere that you should rotate cranks to the point of the biggest pull before tightening. Something like that anyway which is explained better than I can! Didn't think it would make that much difference though. What is the best way to have your chain anyway? Should it be TIGHT?

...or it could be round, but not 100% central on the spider. If you're fussed, you could slacked off the chainring bolts slightly, then rotate the pedals and tap the chainring with a screwdriver to even it out. Then retighten.

Yeah.. you loosen the chainring nuts and then tighten somewhat so that the ring will still move. Roll it around and find the tight spot and whack the chain with a spanner or somerthing. This will shift the chainring back on its bolts. Do this until the tension is even all the way around.

Here's Sheldon's words: http://www.sheldonbrown.com/singlespeed.html#tension

Personal preference (as long as it's not loose enough to derail).

Me, I like it tight, not quite binding at the tightspot, and so I can't feel any play whilst trackstanding with right foot at 2 o' clock. Dyagetme?

yeah sheldon says to do that & I must have tried it three or four times

the ring doesn't really move in relation to the spider

but I'll give it another go right now

Me gets ya!

I want my chain tight and silent, not making a brrr brrr sound everytime it needs some lube, I can't adjust this out as there is no play between ring and spider, BUT how is it that the ring it is not PERFECTLY circular, its not like this stuff is CHEAP

the chain will never be 100% perfect due to very slight imperfections in bottom bracket, crank and chainring so don't worry yourself too much over it.

yeah, that's what you're paying for when you buy a sugino bb and chainset - it comes down to accurate
machining and accurate bb installation.

i remember trying sheldon's method of whacking the chain and tightening the stack bolts (does anyone still call them that?) gradually (on a road chainset) but it never made a blind bit of difference. even with new chainrings it was the same. i think you just have to live with it.

That Sheldon trick doesn't work! Not on good quality stuff anyway, with junk parts it might I don't know. The ring should fit on the crank exactly, there shouldn't be any movement.

don't run the chain so tightly, this is a problem that will appear to be at it's worst when the chain is tight. There's a place just slacker than where you are, that's where you need to be.

Zen rings are dead expensive, its weird that you're having problems with noticable chain tension issues. I use the vanilla 75 chainrings and have no chain tension problems; pretty even tension throughout the cycle. Have pretty much the same setup as well: Phil hub, EAI cog, Sugino 75 cranks + BB + ring.

BTW is this a Sugino Zen ring or a Sugino Zen messenger ring? Could understand if its a Zen messenger ring as they're pretty basic.

One easy thing to do is to swap the ring (if you have a spare) and try it with something else. Should help narrow the source of the problem.

i still call them stackbolts, but only because i didn't know what the hell they were and had to look 'em up on sheldon's site

Well I am glad to find out that it is not just me who has been wacking my chain sheldon style only to find out that this method patently does not work on a 'quality' set up

Sure I can slack the chain a little bit

But really the tolerances really ought to be a little tighter

It's not a biopace ring is it ;-) ?

Sorry to dredge this up but I am now having similar issues.

New Miche Chainring. New EAI Cog. More 'play' at one foot forward than the other. Will try the sheldon method tonight but not holding out much hope after reading this.
Could it be that the secondhand Miche cranks are forcing the ring out of round?

I'll try the tap tap tap-eroo.

The problem might be a combination of the chainring and the crank spider.

It's likely to help by rotating the chainring relative to the spider, i.e. take the chainring off, noting where it was. Then rotate it forwards by two arms, and try again. If nothing else, it will move the slack spot to somewhere else, so it won't be at all obvious when you're trackstanding.

I've never done the sheldon thing yet, but understand what it tries to achieve. However, it may just be that there is a sligh high spot on on the chainring and on the spider, the trick may be to get these high spots 180 degrees opposite so they cancel each other out.

Therefore, try out all five rotational positions in turn to see which gives the best results, then when you've found the best do the sheldon thing with the stack bolts.

timmins - you beat me to it!

haha

I used one of these for a while. I convinced myself if was safe (cos I was too tight to buy a crank puller).

It sort of worked, as long as the tension was meticulously maintained.

Then a near-death experience crossing Farringdon Rd at 25mph finally persuaded me that, in reality, Biopace and fixed are a terrible idea.

i love a good chain tension thread. i fucking love it. that's what this place is all about!

I've tried the sheldon chainring truing/tensioning method and have experienced some minor improvements but not what I was looking for. When cleaning my chain recently though I did notice that the ring moved away from and closer to the seat tube so it's down to the cranks or the BB. It's annoying because you have to set your tension looser than you would like to avoid the binding, but then it's too loose.

So I'm thinking about new cranks myself but who knows, it could be the BB. How can you tell if it's the cranks or the BB? Don't want to shell out on cranks and then find out it was the BB all along.

Let it bind, let it bind, let it bind..

You'll get fitter and they'll eventually wear down and be smooooth :)

gah! just noticed that My sugino has this issue as well.


Shit it.

they wear in and it all becomes all nice and smooth

hear it people.

I'm tempted to try out this binding thing as the chain tension problem has been annoying me for months. I've also just got myself some chain tugs for the first time as the track ends have started slipping a bit and don't want to risk stripping out the hub threads.

You sure it won't knacker the hub and BB bearings?

Fsck 'em, that's what I say!

Nah, London weather is more likely to knacker the bearings. Don't OVERtighten them just get tension so it's not dangerous (if a little tight).
I've ran the Raleigh with iffy tension for ever and no problemo but I don't care about wearing shit out faster, I do care about dropping a chain.

the corpulent antipodean speaketh the truth.

If you set it so the tightest point is *tight* but not fully binding then ride the fucker it WILL even out, I've done it with three seperate drivetrains over the last year.

with a decent chainline, it has to be pretty damn slack to drop, and slack all over to boot

I gave it a go today. Turned up the tension just short of binding and what do you know, the smoothest ride I've ever had. Admittedly a touch harder work but worth it for the gain in control. The left/right leg power balance feels more even too. I also felt that it was easier to slow down using the pedals which I usually find extremely difficult and have to stand.

So thanks guys. I don't think I'll shell out on new cranks after all. This will do me for a while.

Rotated my chainring two holes and voila. Perfect tension all round.

Cheers fellas.

After reccommending this based on logic alone, I tried it last night and it worked a treat. Much smoother + quieter now.
Everyone with tension issues should try this first.