Will This Gear Work As A Tensioner?

[Russ McClay]

I've got the typical China Girl/Mountain bike setup. Little white, wobbly, fragile-looking teflon roller wheel tensioner. I'm wonder if I could replace it with this:

http://www.agrisupply.com/or-idler-sprocket-bore/p/18300/

My main concern is that it says it is 1/2 inch bore.

Thanks,
Russ

 

[2door]

1/2" means you'll need a 1/2" shaft to mount it on. If I could make a suggestion, find a good quality skate board wheel, cut a groove in it to fit your chain and use it instead of a sprocket.
Look for a wheel that is one piece instead of some of the cheaper ones that have a thin outer coating. When you try to groove those they come apart. A one piece wheel made of polyurethane is the best route. Most of them have a 5/16 or a 3/8" bore and they have bearings. Much easier to mount. The urethane will also run much smoother and quieter than a steel sprocket.

Tom

 

[Russ McClay]

Hi Tom --

Thanks for the reply.

1/2" means you'll need a 1/2" shaft to mount it on. If I could make a suggestion, find a good quality skate board wheel, cut a groove in it to fit your chain and use it instead of a sprocket.
Look for a wheel that is one piece instead of some of the cheaper ones that have a thin outer coating. When you try to groove those they come apart. A one piece wheel made of polyurethane is the best route. Most of them have a 5/16 or a 3/8" bore and they have bearings. Much easier to mount. The urethane will also run much smoother and quieter than a steel sprocket.

Tom

I've heard of the skateboard wheel solutions many times here. I live in Taiwan and don't even have a garage, let alone a drill press; finding some kind of shop to do anything out of the ordinary would be very difficult, I've lived here over 25 years and wouldn't know where to start asking. Too bad someone doesn't sell these.

I've only put about 25 miles on my this first build of mine. Chain is aligned, 3/4 inch slack...and the wheel is already looking chewed up. =)

Maybe I'll just buy a couple of extra standard kit wheels for spares.

Russ

 

[Russ McClay]

Hi Tom --

Look for a wheel that is one piece instead of some of the cheaper ones that have a thin outer coating.

Tom

What do you think of this design?

http://www.ebay.com/itm/White-new-Motorized-Bicycle-Bike-Idler-Pulley-Chain-Tensioner-/140778519788

Russ

 

[2door]

Hi Tom --



What do you think of this design?

http://www.ebay.com/itm/White-new-Motorized-Bicycle-Bike-Idler-Pulley-Chain-Tensioner-/140778519788

Russ

Russ,
I'm not sure how that wheel is supposed to work. They actually need a groove for the chain to run in. That one appears to be flat or slightly rounded on the outer circumference.

Some of the tensioner wheels have a bearing and some rely on just a steel collar. If you order one make sure it has a bearing. Obviously the bearing will run better. If the wheel, plastic or nylon, is aligned with the chain path, chain centered in the groove, there really shouldn't be that much wear on it. Most if not all tensioner brackets need to be bent/twisted slightly to get the wheel to run centered on the chain. Also proper lubrication of the chain will help reduce wear on the tensioner wheel.

Tom

 

[mybike1]

I'm using a idler wheel from an old Schwinn tandem... actually I'm using 2 of them... one about 8" or so after the engine sprocket and another about 8" or so before the rear sprocket... They work great... I just had to make and weld a little bracket for them to mount to. You can usually find them on ebay for pretty cheap.

 

[Russ McClay]

Well, mybike1, that looks like it would work fine!