Question for Brad

[gbbwolf]

Was thinking today while I was doing my build.
Has any one tried using a bottom bracket welded under the seat,for a chain tensioner. Like a BB from a 20 inch bike with the pedals removed.
I forgot to order a pulley for my build.
Or maybe putting a freehub under the seat with like just one gear.
I will have to try it I guess It might work.
Will let ya know when I get it done.

[n9viw]

Don't see why not, Brad used a BB with a single gear on it as a director on one of his bikes, I forget which... it's not necessarily a tensioner, as it's not imparting any tension to the chain, it's just acting as a 'bend point' to change the chain's direction.

Now, if you actually wanted to TENSION the chain (in addition to or instead of the derailleur hanger) you'd have to make it adjustable, but I don't know how much tension the return side needs to keep the chain from flopping. I guess that all depends on how long the run is.

[trikeman]

I thought about using a BB on my DW for that, and even posted a picture of it on the old forum, but in the end, I decided it was too heavy compared to the simple pulley. If you wanted to make it a jack shaft, that would be another story.

http://www.atlantamusclecars.com/Paint/Idler1.JPG

[AtomicZombie]

SKyWalker used a system like that, but yes, it would be extra weight.

http://www.atomiczombie.com/gallery/bradgraham/skywalker.htm

Brad

[n9viw]

Okay, I must have been thinking of Joey's AlleyKat: http://www.atomiczombie.com/gallery/joeywallace/swb.htm
There are several others in the SWB gallery that feature that mod, so I'm guessing it was part of the original plans in the AlleyKat that didn't survive the jump to the Bandito.

[gbbwolf]

Yeah just wanted to use it as a bend point not a tensioner my bad.
UMMM weight whats that. Already using 1.5 inch 14 gauge so the extra what 3 lbs isnt much.
This thing will be a monster.........
But then im a monster. At 6ft7 350 lbs. LMFAO

No jackshaft for now May consider it if I decide to maybe add an electric motor later.

[trikeman]

No reason it shouldn't work as a bend point, and it would be a bit more efficient than the pulley. Bottom brackets are free if you get old bikes, so you may as well go for it if weight isn't a consideration.

[gbbwolf]

Yeah I got lots of bottom brackets and other parts already chopped up and sitting in plastic storage totes.
Small shed so I just cut em up and put them in totes.
Store them outside.

[TheKid]

Very true. If weight isn't a factor, that's the way to go. Chains are designed to work with sprockets, but they'll work with pulleys. If at all possible, I'd rather use a sprocket than a pulley.

[AtomicZombie]

But....

As a chain guide it will be prone to derailments as you hit bumps. A nylon pulley is smooth, weighs nothing, has walls to keep the chain in place, and only needs a bolt to hold it in place.

Brad

[gbbwolf]

The BB I was thinkin of using is from a 20" bike and it has steel chain guards that ride alongside the crank actually looks like a nylon pulley but with a sprocket it was on a next thunderbolt bike.
But The kid decided he wanted it back after he gave it to me.
He called 5 mins before I chopped it up.
He got lucky.
So I will be looking for another way.
I may just design some sort of chain stay on either side of it.
I just got my hubs welded to axle today and made my brake adapters for the axle's. Wish I could post pics.
But my camera is DEAD...

[SirJoey]

I used a combination of both methods on this one, which seems to work well. Of course, the BB was already there, & this was the easy (lazy) way to do it.

Still, I think next time, I'll weld a round plate over the BB, & mount another pulley there, for aesthetics, as well as a slight savings in weight.

http://img261.imageshack.us/img261/6672/chainmanagementkq0.jpg

http://img261.imageshack.us/img261/4962/chainmanagement2rk8.jpg


http://img384.imageshack.us/img384/7131/sirjoeysigmedij1.gif