Printable View
On my "new" 'cross bike, dubbed "The Tank" by some and "The Frankenbike" by 'Nater, I have a single 46 up front. With no derailleur up there, the chain has a nasty habit of leaping from the ring at inopportune moments.
How can I keep this from happening? Right now, I've got an old front derailleur on there, just bolted on and adjusted to keep the chain in place, but there must be a better solution.
Any thoughts?
Any thoughts I can implement before my race tonight at 6? :D
You could rig some sort of chain tensioning device. One possibility is to clamp some sort of roller to the chain stay that basically pulls the chain up.
just leave the derailleur on there, waste zero more time and money. don't be a bike nerd. why fuck with your bike if nothing's broken?
Well, first, I like fucking with my bikes. Heh.
Also, the derailleur fix doesn't work that well. There's still a lot of play. The advantage is that when the chain hops now, the derailleur holds it and I can sometimes get it back on the ring without getting out of the saddle.
ugh. that's all you dude.Quote:
Originally Posted by Cornholio
not sure what kind of spider you're running, but you could maybe put a bigger ring on the inside and a bigger one on the outside to just hold the chain in-between on the 'drive' ring? i've seen that work on the back to ghetto-rig a singlespeed (with a hacked derailleur for a chain tensioner).
plus, you'd be nicely adding some weight to make sure you're over your self-imposed 30lbs cross bike weight limit, so you've got that going for you.
I've gone the single ring route. I used a Third Eye chain-watcher on the inside ($10) and a chainring guard in place of the big chainring ($25). Works like it's, uh, single-minded in purpose. Should be able to get all that from your local shop, and possibly even in time for your 6 PM race.
But, then, sometimes its just easiest to throw money at a problem to make it go away. Ergo, the best specific application: CX World's single ring kit.
[edit] never mind, those guys are out of stock.
How long are your dropouts? SSs traditionally have long dropouts for this very reason. Loosen the rear wheel, pull it back a little to tension the chain, retighten. Done.
If your dropouts are too short for this, take a couple, or more, links out of your chain.
I am assuming that it is not a single speed, just a single ring up front. Are you still running a rear cassette?
First off, does it happen with only a few of the gears? (like only on the 15 or whatever). If it only happens at one end of the cassette, I would start messing with chainline. It may be that it is too much angle for the chain to handle.
Make sure your chain is clean, having a dirty chain really messes with shifting I have found. Dirt makes the cahin 'stiffer' and can't flex properly.
Another suggestion is to take a few links out of the chain to give it a bit more tension.
Lastly, I don't know what combos are best for cross since I ride road/track and mtn, but the 46 in combo with whatever cassette you're using may not be the best for tension and shifting. A different bigring may be neccessary.
Good point Oarhead, I totally assumed it was a SS. If there is a rear derailleur, maybe it's old and the spring's getting worn?
It's not a SS, its just single front ring. The rear derailleur is pretty good. I'm going to make sure the chain is the right length, and if I still have problems look in to a solution like He Who Has No Name mentioned.Quote:
Originally Posted by Viva
I also thought about this ghetto rig- a 2" long piece of 3/4" pvc clamped to the seat tube and positioned so that the chain runs through it and right on to the ring. I was thinking if I cut one end on a diagonal and maybe made a little notch, it could get pretty close to the ring. It would be like the derailleur but exert a little more control. Ghet-o. But it might work. Nah. Actually writing it down made it sound a lot worse than I thought. :)