CMcMahon

My problem is this: no matter what I do, my rear wheel slips forward (I hate this, because I like my chain tight - I'm talking scary, could very easily snap tight here). Even after wiping any and all grease off the dropout slots and the lock washers, locking the wheel in place with a pair of old brake pads and a 15mm socket, and cranking down on the bolts with a tire iron, it still slips forward.

Any suggestions? I have a friend that works at a machine shop making some reverse chain tensioners for me, but it's going to be a while before they're done.

FarHorizon

Are you using steel washers with radial teeth? Are the teeth on your washers still sharp and not rounded? I tighten my single-speed hand tight with a 15 mm wrench, and my wheel stays in place despite my STANDING on the pedals (I weigh 280 & have 175 mm long crank arms!). Standard lock washers merely keep the nut from backing off - they do NOTHING to keep the axle in place.

Ronin

Tug nuts? Mudflap girl tug nuts?

CMcMahon

Yes, steel washers with radial teeth, and they're still sharp.

supcom

Perhaps your chainring is not quite as centered as it needs to be. After you tighten down the chain and turn the crank, the eccentric puts enough force on the chain and something has to give. In your case it's the wheel position.

Or, perhaps you're tightening the wheel with the eccentric at is furthest forward so when you move the crank to any other position, the chain slackens?

As an aside, why are you obsessed with chain tension? Too much is not a good thing.

grolby

Two things: first, if you can get over your obsession with insane chain tension, you might find that the wheel stays where you leave it. As supcom said, could be that there's a lot of force on the chain because of how tight it is. No chainwheel is perfectly round, so having just a teeny-tiny bit of slack in the chain is good. It's a bike, not a suspension bridge.

Second, is your axle bent? If so, uneven force could be causing it to rotate, making your wheel slip forward a couple millimeters. This could even throw the chain off of the cog if it moves enough. This wouldn't happen in your case, but it was enough to destroy a ghetto singlespeed conversion I made last year by taking off the derailer and putting the chain on the middle freewheel cog. Wheel slipped, chain jumped up to the next biggest cog, rear hub pretty much self-destructed. Fun times!

Ronin

Most likely a grinder.

MichaelW

Use track nuts with a built-in washer.
Tighten them with a box-end wrench (uk: ring spanner).
Apply some foot pressure to the end of the wrench to tighten.

lyledriver

We're talking BMX here, right?

I run a primo chain tensioner on my drive side, which happens to be my non grind side.

Some (that like to ice pick) have made their own non adjustable tensioners that are D shaped, and plug the remainder of the dropout. Others make them much like a normal tensioner, but with just a hole for the axle, then enough metal to go back to the end of the dropout, and a 90* fold.

FlatTop

Ridiculously tight: Jam a hammer handle between the chainstay bridge and the tread of the rear tire and try to tighten the axle nuts so the wheel is straight.

Absolutely not recommended violin-string tight: Deflate the tire about halfway and pop the hammer handle in as above. Then inflate the tire.

Please don't get hurt, and don't do this stuff on a frame you care about.

CMcMahon

The chain is pretty much equally tight on no matter what direction the sprocket is facing; I'm not saying that it's perfectly true, but it's non-noticeaby un-true. When the chain slackens, it's equal on all sides, and the rear wheel stays centered.

I'm obsessed with chain tension because I've found that I can't ride very well with a loose chain. I get much more squirrely in the air, and feel very uncomfortable doing fakies and rollbacks.


There is a bit of slack; enough for me to push the chain down enough so that it almost hits the top of my u-brakes.

The axle is most definitely not bent; it's a relatively new, hellow, 14mm axle that's never taken much abuse.


Correct, but I'm pegless, which is why I don't understand why it keeps moving forward so easily, especially since I rarely stack on my back wheel or do anything that would force it forward.


My dropouts are too short to run a normal tensioner, and the custom tensioners that my friend is working on are basically like the d-plugs you mentioned, except for he fact that they're adjustable to fit a variety of frames.


Actually, I use a socket inbetween the chainstay bridge and the tread, and use a pair of old Kool-Stop MTB pads to center the wheel between the chainstays.