Walmart cruiser converted to CB from 5 Speed.. Chain adjustment???

[DJ Bill]

I was almost all buttoned up on Lulu, the latest pink bike to hit my stable.. and I discovered I couldn't get the chain tension right.. Either way too tight, or loose enough to whip around and pop off. The rear dropouts are vertical....no fore aft adjustment at all .. Even a half link didn't get the adjustment where it worked.

Any ideas?? I'm about ready to file a flat in the new rear axle to get the 1/8 inch I need..

No pics, the bike is already out for a ride..but I don't like the way the chain and rear wheel fit.

 

[horsefarmer]

I believe they make cam type bottom bracket bearings to adjust tandem bike chain tension - might cost more than your project tho....

 

[Crassly]

Some tandems also have an idler to take up slack.

 

[DJ Bill]

I'm figuring someone here has used an idler and might have a better idea than I where to get one reasonably.. I do have a junk derailleur or two but this is supposed to be a "nice" bike without any cobbling..

 

[Crassly]

Any chance that changing the rear cog to one or two more or less teeth would make the necessary difference?

 

[DJ Bill]

After reading Sheldon Brown's Fixie pages about the same issue that is the conclusion I have come to if notching the axle won't do it. Tensioners and coasters don't work well together according to his site.. and I can see the top getting too floppy during braking even with a spring tensioner on the bottom run.

Now I need to go through my selection of rear cogs..

 

[Bicycle808]

I understand no pics, but how bout some info? You put a 5speed IGH on there? The bike had a coaster brake originally, but had vertical dropouts? I've never seen anything like that, aside from an EBB setup. What's going on with the build. I bet there's a simple fix or 2 for this, but we gotta figure out what's actually going on.

 

[DJ Bill]

It was 5 speed, with derailleur... Now it is a single speed coaster hub.I thought I'd said that but I see i didn't..oops!

 

[user 135]

You could try a Ghost ring to take up chain tension. This may work and be safe on a C/B.

 

[Bicycle808]

It was 5 speed, with derailleur... Now it is a single speed coaster hub.I thought I'd said that but I see i didn't..oops!

Ohhhhhhhh. I was thinkng it was a c/b bike that you converted to 5speed. Yeah, pulley-type tensioners won't work with a coaster, as you learned on sheldonbrown.com. EBB options, as mentioned above, are often incompatible (require a proprietary shell) or else they cost a ton ( http://philwood.com/products/bbpages/philcentric.php ) Filing the axle will only score you a few mm, max. I see you're already using a "halflink".... A "magic gear" could save the day, and even more likely, a magic gear as well as a filed axle might be your only hope. I've seen folks use ghost rings, but i've never done it myself.

Whatever you end up doing, good luck! Remember, finding a magic gear combo coulod involve changing the front OR the rear OR both sprockets. I'll keep my fingers crossed for ya!

 

[GuitarlCarl]

I took the spring off of the tensioner, made my chain as short as possible, and used the tensioner to take up the bit of slack left. ALSO, IT WORKS WITH MY COASTER BRAKE. As always, your mileage may vary... but yeah, remove the spring...


Carl.

 

[Wildcat]

I tried the same thing on a beast. At first it worked, but with coaster brakes, a tensioner with spring won't work for long, when you really get on the brakes, it will bend. A solid thing, like GuitarCarl is using, will work, like the adjustment on the front chain on a tandem.

 

[DJ Bill]

The bike is ridable , with a used chain, but the chain is pretty tight..I have to put the half link in place and then make the chain go up on the front sprocket..If I put the wheel all the way in the dropout slot it gets musically tight. (Like a banjo string) I'm thinking just a few mm might be enough...We will find out soon, when I get the bike back here. It sounds like the recipient is liking the bike so it is time to finalize the tuneup and final details.

Thanks everyone for all the tips! I hope that the magic sprocket might work if the notch doesn't, otherwise it is off to the land of rigid tensioners.

 

[DJ Bill]

http://www.modernbike.com/dimension-chain-tensioner-black-chainstay-mount

I wonder if this would work....does anybody out there use one? I think I could make one but maybe buying would be the smart thing in this case.

There are a ton of stripped derailleur type tensioners on the site as well, all say do not use with coaster brake.

 

[GuitarlCarl]

It's all about the slop in the chain. Nothing will work with a lot of extra links, like a derailleur, but if you take out all the extra chain you can, a coaster will work. The tensioner above doesn't have a gear to track the chain but looks like it'd probably work... I have no experience with that style...

Carl.