Singlespeed & Fixed Gear - Chain Tension, how much?

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View Full Version : Chain Tension, how much?


jbrow1
11-27-12, 10:24 PM
How tight should I set my chain? Also, how tight should the chain/gear relationship be? I just put on a new track gear (changed from SS to fixie) and it seems the chain wants to stick on it as it goes around. I am assuming it will wear together and not be a problem. Just a tighter fit than I'm used to with my geared bikes. Have to check what chain it is, but it looks fatter than my 8 speed chains.


striknein
11-27-12, 10:28 PM
1/2" of deflection will do you just fine, though some like the "track slack". If it feels like it's binding, it's definitely too tight and you'll wear down your drivetrain prematurely.

plowmanjoe
11-27-12, 11:40 PM
i like to have it as loose s possible without the possibility of the chain dropping. use a wrench or something and try to derail the chain while the wheel is turning. if it doesn't fall of the cog or chainring with that test, it never will with any kind of riding.


captsven
11-29-12, 12:07 PM
1/2" of deflection will do you just fine, though some like the "track slack". If it feels like it's binding, it's definitely too tight and you'll wear down your drivetrain prematurely.

I always wondered if this was 1/2" from the tightest or loosest spot in the rotation of the crank? Or neither?

Bat56
11-29-12, 12:18 PM
Just enough.

ThermionicScott
11-29-12, 12:26 PM
Since my fixed-gear is built up from old used road cranksets and bottom brackets of dubious machining, I keep my chain a little slacker than average. When I measured it, it was about 1.1-1.2" of total play, up and down at the tightest point.

Nowadays, I just spin the cranks and sight down the chain, looking for a little bit of droop throughout the crank rotation, but not enough slack to feel "sloppy" at the pedals. I haven't dropped a chain yet, but I will revise my method if I ever do.

striknein
11-29-12, 03:44 PM
I always wondered if this was 1/2" from the tightest or loosest spot in the rotation of the crank? Or neither?

Neither, if you're using quality parts and install them properly.

captsven
11-30-12, 05:40 AM
Neither, if you're using quality parts and install them properly.

What parts do you have that keeps your chain tension equal throughout a full chain ring rotation?

striknein
11-30-12, 06:04 AM
Sugino 110bcd single speed ring, Surly cog, and very careful adjustment.

alecjahn
11-30-12, 07:01 AM
In the past I have loosened the bolts on my chain ring a little bit and micro-adjusted the slop/play between the chain ring and the crank while slowly turning the wheel. One can find the high and low spots in your ring and move it around accordingly.
Then, of course, tighten the bolts again before riding. :)

Though I'm sure this action isn't necessary on a *nice* ring/crank/cog combination, which I don't have.

Bat56
11-30-12, 07:13 AM
Get the bolts just a little less than tight. Rotate the find the spot with the tension. Wack the chain with a wrench or a karate chop. Rotate again. Keep doing it until the tight/loose difference gets smaller and smaller. Tighten the bolts.

Or screw it. I screw it.

striknein
11-30-12, 08:13 AM
I had a write-up on centering a chainring here somewhere, but I swear I have no idea what happened to it.

hairnet
11-30-12, 08:34 AM
http://sheldonbrown.com/fixed.html#tension

striknein
11-30-12, 08:59 AM
I don't particularly like that writeup, because using a tool to strike the chainring makes it too easy to overcorrect. I like squeezing the chain instead.

hairnet
11-30-12, 09:08 AM
makes sense. I need to do it to my bike

Coluber42
11-30-12, 09:17 AM
I like mine as tight as possible without binding anywhere in the crank rotation. BTW, it's definitely possible to have nice parts and still have high/low spots; I have a T/A crank and ring, and it still has those a little. I had a Shimano crank and chainring at one point that had less, but this crank has lower q-factor, which I prefer.
If it's really too tight, it can destroy the bearings in your bottom bracket or hub surprisingly quickly. I cranked it down once at the beginning of a 400k because I was too lazy to adjust it better, and found myself limping along with a quickly worsening bottom bracket until I got to someplace where I could get a new one... but a good 100 mi of that ride really, really sucked.

I like it as tight as it can be while allowing the drivetrain to spin freely. I find too much slack to be uncomfortable, and more fatiguing over long distances... plus I usually need to stop and tighten it every 100-200 mi or so, and if it's loose to start with, I have to tighten it again sooner. :P