Chain Tensioner has 66cc chain tensioner evolved yet; suggestions?

[JunkyardDog]

I have a single speed I want to use for my next build. But it was not also a single speed. It is an '80s or '90s model Trek Antelope 800, with a very high quality steel frame and Araya aluminum rims with large flanged hubs, stainless steel spokes, etc. I removed both derailleurs, and the larger front chainring. I have the chain on the smaller front chainring,, and on the middle rear sprocket. I got lucky, and got the chain adjusted right in that position by removing links. It doesn't always work that way. The chain will be way to tight or way to loose. This is a very low geared bike, capable of climbing hills, and cruising on level roads, though at very low speeds unless you can really spin it. I put a much more comfortable seat and upright handlebars on it. My original intention was to use this bike as a "canal bank cruiser" We have a canal nearby, over 20 miles long, with a dirt road on both sides, where motor vehicles are prohibited. So it makes a nice place to ride a bike. Unfortunately my knees are slowly getting worse, so I built a Huffy Cranbrook with a Staton friction drive and RS engine. It still works fine, but I now want to build a MB out of my Trek, with either a Chinese engine kit, or a 4 stroke engine kit The main issue with these kits is the chain tensioner/idler. I know that from experience, having destroyed a rear wheel and almost crashed.

I also came up with the idea of welding a piece of flat steel stock from the seat stay to the chain stay, and putting some kind of super heavy duty roller or rubbing block on it. I believe I've already seen something like that on this forum. It would have to be strong enough to hold the chain in place no matter what.

 

[fx-2]

That should work . There a bike builder that make a mount kit that doesn't use a idler here the link http://venicemotorbikes.com/store/product_info.php?cPath=29&products_id=34 . Check with Norm . Dan

 

[V 35]

Please consider the following points ; Rear wheelstays do not run
parallel to chain path [ which is straight ] but taper toward wheel.
This adds to the problem. I wound up cutting the tensioner bracket
and welding it to the chainstay. I tacked a single corner, tapped the
bracket to run parallel to chain [ offset on stay ] and welded it solid

Check out a Sportsman Flyer, they got it right ! Many spring loaded tensioners are coming out. If your running a coaster brake,
forget having a pedal side tensioner / modded deraileur. I will work
well on a freewheel hub, but will backlash [ and break ] when coaster
brake is applied. I learned the hard way.

 

[Hamguy]

Spring loaded chain tesioner

Hi guys! After worrying about chain adjustment on motorcycles I have owned and now with these little bundles of JOY, I decided to fabricate my own version of a chain tensioner. It turned out so well I made a few more and put them on eBAY - Sold 4 the 1st week! First I tried to make one with the pivot point inline with the wheel and found my chain would rub on the pivot bolt. After some head scratching I came up with the idea of moving the pivot LOWER. BINGO! Next was where to anchor the spring to the bike. Drilling a 1/8" hole in my kickstand bracket provided the perfect spring tension with the springs I had bought. The photo shows my tensioner prototype with the 1st pivot hole in it with the new LOWER pivot point welded on. Feel free to copy mine or, take a look on eBay to see a variety of different ideas. Ride SAFE and have FUN!

 

[Purple Haze]

Cavi Mike is right, if the sprocket is aligned perfectly, there will be few if any problems. Most idler pulley problems are caused by the chain being misaligned and pulling to the inside. Also, the idler bracket needs to be bent to align the chain. If all this is done correctly, there should be very little wear on the roller. The new rollers come with bearings, but if you don't care for the plastic construction, a simple fix is to take a skateboard wheel, put it in a lathe, and cut a channel in it. This has been done many times, with great longevity. The best fix, though, is the spring-loaded tensioner. Those quality gears have a lot of runout in them.

 

[MusiCALpuLLtoy]

idler

dude,
i attached a moped motor to the back of a 10 speed bike. for a tensioner i used a rear derailer. it works great .

 

[V 35]

Could FX re-shoot the tensioner photo ? Black doesn't photo well, and the details are obscured. The bike looks great, love those chain adjusters. Us ' independents ' seem more bent on safe tensioners than the manufacturer does. that's sad.