ETN612

Ok. So I posted a previous thread in which this same issue was addressed (https://www.bikeforums.net/showthread...ues?highlight=). I had tried centering the chainring on my stock SE Draft Lite crankset to no avail (it was just a pretty eccentric and slightly bent chainring), and I had hoped that the new crankset I was getting (All City 612 track crank w/ included 46T 144BCD chainring; had a new Shimano bb installed along with it - all installed at reputable LBS) would fix the problem, and it seemed to initially for the most part. Soon after that, I got a new wheelset (velocity deep v w/ velocity hubs and dtswiss comp spokes) and track cog (Shimano Dura-Ace 15T). That made the chain tension more even still. So essentially, my ENTIRE DRIVETRAIN is pretty much brand new. But, the unevenness in chain tension still managed to magically return somehow, and yet again, trying to center my new chainring on my new crank seems to do nothing after I re-tighten the bolts. At the cranks, tightest point, it's perfectly tight, but at it's loosest, there's pretty noticeable chain droop. So, after making the upgrades and having the problem resurface, understandably, i'm ****ING LIVID. Fixed gear bike repair is supposed to be ridiculously simple but i've had seemingly nothing but problems for a long time now and i'm absolutely furious that I haven't had a worry-free ride on my fixed in a long time. It's keeping me from riding my bike even close to how often I actually want to ride it. I just want to ride without having to worry if i'm damaging anything more by riding my bike in its current condition.

So, in short, what else could I possibly do to banish this chain tension unevenness from my life? I was hoping the upgrades would do away with it but it seems i'm mistaken. I just don't understand how this could still be a problem after completely replacing my drivetrain (not that I made the upgrades solely to fix this issue, but I just hoped this issue would work itself out naturally after having replaced everything that is part of the drivetrain.) The only thing I can think of is completely taking off the chainring, greasing the contact points, and tighten everything finger tight and try to recenter the chainring from there.

Also, as a related question, when centering a chainring, is it possible to retighten the chainring bolts too tightly in a manner that would make a chainring go askew from it's newly centered position?

Scrodzilla

Of course. Centering a stubborn chainring can be maddening.

There's a really good chance of the All-City chainring being slightly out of round as well. AC stuff is good but it's not exactly what I'd call high end.

ETN612

Also, Scrod, I saw that you posted here saying my bb shell might be crooked on my frame, dunno if you delelted the reply or what. I mean it, looks like it straight, and not crooked in respect to other areas of the frame, but i'm sure that even the slightest crookedness could have a noticeable effect, even if it isn't plainly visible... I really hope this isn't the case, it's gonna be a long time till I can afford the frame I want to eventually upgrade to (All City Thunderdome).

ThermionicScott 

If it's really bad, try rotating the chainring on the crank by two or three positions.

ETN612

Ok, good to know, i'll just have to retighten the bolts back more carefully and gingerly I guess? And i'm just kind confused because when I put the new wheels w/ new cog on it seemed to be almost gone and yet the problem has resurfaced out of nowhere. Who knows. And yeah, I can understand the AC chainring being out of round a little bit too. If that's the case then at least i'll only have to get a new chainring eventually, because the crank itself (along with the new bb) i'm very satisfied with.

Scrodzilla

I deleted my post because while a slightly misaligned BB shell would create some slight issues, the chain tension would still be consistent all the way around. You would never be able to tell if your BB shell is crooked without alignment tools.

europa

Maybe you're worrying too much. Set the tension so the tightest point has the right tension then ride and enjoy. I wouldn't mind betting that once you stop worrying about it, it'll stop being an issue.

ETN612

I'll try this and report back, thanks for the reply.

Scrodzilla

And this.

ETN612

Hahaha, that's probably true also, i'm absolutely anal-retentive when it comes to stuff like this.

Scrodzilla

Dude, it's a bicycle, not a spacecraft.

ETN612

Hahahaha, be nice, i'd never even attempted tinkering of any sort with a bicycle until I got my fixed, so i'm still a total new jack in the realm of bicycle mechanics and repair. I just want to learn because I feel like a total sucker every time I head down to my LBS and pay them to do something that probably takes them 5-10 minutes when I know I could probably do it myself. But at the same time, I get REALLY easily discouraged and down on myself when I can't get the hang of something and unfortunately bike repair seems to be following that trend.... so this is just a maddening process for me in general, haha.




Anyway, I just tried moving the chainring over on the spider a couple spaces, and then tried to center it very meticulously and carefully 5+ times, and still, no matter how gingerly and carefully I retighten the chainring bolts or in what pattern I tighten them back up, the unevenness returns upon the chainring bolts being completely retightened, even though it looks as though I have made a significant improvement (BEFORE I retighten the bolts, that is). I'm just perplexed by the fact that the problem returned seemingly out of nowhere when it had pretty much disappeared for a few days after I had replaced everything in the drivetrain. Also just confused how so many people manage to get their tension relatively even and yet I can't even seem to alter mine in the slightest. If it's because the AC chainring is out of round, then that's genuinely frustrating because then it's not much better in regards to roundness than the chainring (which was also bent) that came with the ****ty Draft stock crank.

I am probably just worrying too much about it too, but I'm sure that the amount of chain tension unevenness that i'm experiencing is definitely more than what is to be expected. I'm not worried that my chain's gonna fall off or anything, i'm more concerned about putting unnecessary stress on my parts when I ride.

Oh well. I'm just gonna stop and try again tomorrow before I chuck my bike across the room in anger.

Nagrom_

WHY ARE YOU YELLING AT ME?
allcapscensor

tombc

whenever I put my wheel back on it usually has some arbitrary amount of slack. if I can push it inboard, rotate the crank and have the chain not derail I know i'm not going to die. Do that at the slackest part of your drivetrain, and ride or don't ride depending on the outcome.

Right now I've got noticeable droop going on and I don't care as long as the chain can't come off.

Mumonkan

i have literally the cheapest crankset and chainring i could buy, its horribly out of round no matter how much time i spent centering it

set it to tension at the tightest point and stopped caring about it, no problems 2k plus miles in

ETN612

I'm not too worried about derailing the chain or anything like that, i'm just kinda paranoid that riding with uneven chain tension could put a fair amount of unnecessary wear on my components due to rapid fluctuation in force that is applied to my cog and chainring when the cranks are spinning. I'm probably just thinking of ways in which uneven chain tension could damage my bike in any way when in reality it probably doesn't make enough of a difference to have that sort of effect. I'm just a paranoid guy, hahaha. I tend to consider consequences that probably aren't even really present. Plus, I ride brakeless so i'm just concerned that if I have to skid or skip stop in an unforeseen panic situation that I might snap my chain if I try to skid or skip at the loosest point in the crank orientation (which comes when the pedals are roughly parallel to the ground, i.e. my usual pedal position for initiating a skid)

ETN612

Well I have to say that puts my mind at ease a bit. Good to hear from another person that they've ridden with no problems with a decently eccentric chainring.

europa

COZ IT'S FUN

europa

I run Miche at the front and Dura Ace at the rear on the Hillbrick and there's a small amount of variation - never bothered me.

The Europa's first incarnation had the original 80's crank, ancient chaining and some cheap rear cog. Lots of variation, not a problem. Later she got a Sugino crankset with Dura Ace at the rear - again, some variation but not a problem.

I've even tried the centering trick and decided it was just an interesting way to give yourself the tom tits.

Mate, variation isn't going to smash things up. Having the chain too tight may. At the other extreme, it can be very loose before falling off. Methinks thou dost worry too much

sinikl

you could always reindex the chainring by uninstalling and rotating it so the tight spot is at skid central (or closer)... right? maybe not, just thinking aloud here.

Scrodzilla

Or you could just ride your bike.