Singlespeed & Fixed Gear - Mt Bikers - Tensioner Q

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : Mt Bikers - Tensioner Q


Roasted
07-19-09, 11:17 AM
I have a question about fixed tensioners, such as the Rennen Rollenlager, Sette Chain Guide II, Gusset Bachelor, etc...

All of these fixed tensioners have two lock points. One being the axle, the other being the rear derailleur hanger. I'm trying to understand if something is normal here, seeing as though I own the Sette Chain Guide II.

If you have the chain tensioner on and adjusted properly, then flip the bike upside down so the bottom of the chain was on top, and then push down on the chain a good bit, is it normal for the tensioner to move, therefore slacking up on tension?

Reason I ask is my chain tensioner has a lot of wear marks where the bolt downs are. I wasn't sure if this would be a reason to cause it to be "slippery" for the bolt to grab onto to lock it down properly.

I started to think maybe this was normal seeing as though Sheldon's guide emphasized on how tensioners shouldn't be used with coaster brakes due to the amount of lower chain tension backpedaling causes, since tensioners aren't made to withstand that force.

Just trying to think out loud and get some ideas on whether or not this is normal. I did it totally on accident when I was testing the tension on the chain so, like I said, just wanted to ask. Thanks guys!


psirue
07-19-09, 11:51 AM
wait - I'm not clear about your setup.
are you using a tensioner with a fixed-drive train? if so, dont do that.

Roasted
07-19-09, 12:03 PM
Oh no no, it's just a typical hardtail that I converted to a single speed with vertical dropouts.

It's just I tension my chain with the bike upside down. My habit of testing this was I would pull the tensioner back, lock the bolt + axle down to lock it in place, and then I would use my hand to press on the bottom of the chain (because the bottom of the chain is on the top when the bike is upside down) to make sure the tension is where I want it. But one time I pressed a bit too hard, I guess, and the tensioner moved despite being locked down.

I just wasn't sure if it was normal for the tensioner to move if you press on the bottom of the chain. I understand that the top of the chain carries the tension under load, but still I figured I'd ask if any other fixed chain tensioner owners have noticed this.


enigmagic
07-19-09, 03:27 PM
To clarify he's asking about fixed-tensioners, not using a tensioner with a fixed drivetrain.

But yeah, they aren't really meant to hold their position if you put a lot of stress on the lower section of chain, the point is to keep the chain securely on the chainring/sprocket.

Roasted
07-19-09, 04:11 PM
Hm, sounds good.

Not gonna lie though, I put my spring tensioner back on... it's a cheapie... came with my SS conversion kit... but as long as the spring is stiff it's kinda nice just knowing that no matter what hits the chain the spring will just give and automatically snap back to where it was.

On one hand, the fixed tensioner strengthening the hanger is nice... but I like having an adjustment-proof system. I went on a trail after I posted this and a couple times on a technical trail with some taller rocks where I had to put my feet down and kinda keep my balance, a rock pressed on the chain and did exactly what I did earlier when I was checking chain tension, where it forced the tensioner to move.

I think if anything I'll use the fixed as a backup, and carry a spare hanger with me just in case I happen to wipe out and demolish the hanger.