I knew I saw those chain tensioners somewhere. I'm curious, do you know how long their tensioner is? It doesn't look very long and I'm sure it wouldn't work with my 56 tooth sprocket. My latest tensioner pictured below is 9.75" long.
Chain tensioners
- Thread starter Bikeman08
- Start date
I am new here but wanted to share some pics of my tensioner. Just installed racing chain....wore out the cheap one....works great and reduces vibration, chain slap and noise....the roller is made of UHMW. Just finished my first bike.......
Thanks guys for sharing all of your chain tensioner designs on this forum as I will be adding one on my first build mountain bike. I find the one supplied in the kit to be the biggest problem that I have had so far in my kit build, every other part works okay. The problem that I have is on starting the engine by pedaling; the engine has so much compression that it pulls on the bottom run of the drive chain so hard, that it pulls/tips the chain tensioner out of alignment with the chain and towards the spokes! What I have to do then, is pull the clutch in, reach down and straighten the tensioner in line with the chain and then all is well until the next engine startup. I have the tensioner bolts just about as tight as I can get them without a screw/rivet going into the tubing. I find that a tensioner is necessary evil, however, as a new and maybe cheaper quality chain stretches/wears. By the way, what and where do you fellas buy a good quality chain. BMF
BMF,
You need to secure that tensioner before you continue to ride your bike. If it's loose enough to move every time you start your engine it will eventually rotate into the spokes while you're riding and could cause you injury if the back wheel locks up. Use whatever method seems right to you from those ideas available here but DO SOMETHING, before you get hurt. At the very least you're going to destroy your rear wheel.
As for good quality chain many of us use an industrial brand such as Diamond, or Morse, but you'll want to ask for #41 chain. Ace hardware carries it but so do most industrial suppliers. Grainger, Tractor Supply, and others. Good luck, ride safe.
Tom
Thanks 2Door (Tom), I sure will! Last Friday, it was 54degs F. here in my part of the World (Michigan) and I took a nice ride on some farm country dirt/muddy roads where I had never been before. My little China girl mounted on my mountain bike got me there and back, with a muddy stripe down the back of my jacket and mud on any part of the bike near the rotating wheels! It was a 8 mile ride in all and I loved it! The bike is now down in the basement of the farm house and I'll work on it during the winter and take care of that chain tensioner situation for good! I guess at my young age of 75, I had better do that! BTW; why don't mountain bikes, I have a Huffy, come with fenders? Thanks again Tom, BMF
I recently changed the timing chain tensioner in my Chevy s10 truck. I installed the old one (not bad) on my 4 stroke bike using the original roller bracket. It is made of teflon with a steel backing that gives it flex. It already had a hole on one end, so I just bolted it right onto the bracket. It smoothed out the whole ride and the chain doesn't slap anymore. It is totally adjustable and should last a long time. It doesn't guide the chain at all, so the front and rear sprocket does have to be aligned pretty well on its own. It should be anyway. That's the hardest part of the whole motorized bike build.
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Hey Mrfixxit,
what did you use for the tensioner bracket? Looks like it used to be 2 "tear drop" shaped pieces and you cut one in half.
That bike is sweet! Love the chrome fenders and the drum brake on the rear wheel. Does it have a drum on the front as well?
One last question, where did you get that engine? was it a kit? (okay, 2 last questions...)
what did you use for the tensioner bracket? Looks like it used to be 2 "tear drop" shaped pieces and you cut one in half.
That bike is sweet! Love the chrome fenders and the drum brake on the rear wheel. Does it have a drum on the front as well?
One last question, where did you get that engine? was it a kit? (okay, 2 last questions...)
Tensioner bracked custom made and welded to frame before powder coating....front hub is also 90mm drum brake.....awesome stopping power. Engine is honda 49cc chinese copy.....looks like OEM honda comparing mill marks. Had gearing modified 4 to 1 and strengthened at drive sprocket....recently installed new carburetor and K&N filter.....
here are pictures of my chain tensioner solution for ideas. It is really solid and smooth and it is out of the way so it does not really have a good chance of getting sucked into the spokes. It uses stock kit parts and one 1 1/2 u bolt from home depot. It is a true static tensoner and the chain rolls right over the top of it with very little resistiance. 30 mph at WOT is easy. The trck is to get the plastic wheel aligned in sync with the other 2 gears for a total of 3 points of alignment(triangle of strength) trifecta.
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I have manic mechanic motor mounts and it was real easy to adjust motor to take slack out of chain after getting it as tight as possible and in synch with bike chain slack.
No tensioner here any more... I hope thats a good thing.
I was curious what the slack should be I have it just under 1/2 inch...
No tensioner here any more... I hope thats a good thing.
I was curious what the slack should be I have it just under 1/2 inch...
In my opinion No tensioner is the way to go. I tried to get it tight enough to not use a tensioner, i used 1/2 links and monkeyed with it for a good while without success. If you dont have horizontal dropouts on your frame its a 99.9% chance you are going to have to run a tensioner.
I'd say you would not want any more that 1/2 inch of slack in any case.
Too tight (no slack) means more resistance. Too loose (alot of slack) means wear on your sprockets and chain flying off.
Im not sure of a good rule on how much slack you need - I do like you do, I get it as tight as i can then back it off a hair or so.
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1/2 to 3/4" of slack is what we recommend. To get that measurement leave the clutch engaged and roll the bike forward until you feel the engine go into a compression stroke. The top chain run will then go slack. Measure the up/down slack and shoot for that magic 1/2 to 3/4".
As was said above; too tight and you'll have excess friction at the sprocket teeth and chain rollers, too loose and there's more chance of chain derailment.
We can't stress enough the importance of proper chain tension and alignment. It's all about those two things. Get them right and you won't have chain problems. This applies to any chain drive application. Be it in-frame or rack mount, 2 or 4 stroke engine.
Tom
As was said above; too tight and you'll have excess friction at the sprocket teeth and chain rollers, too loose and there's more chance of chain derailment.
We can't stress enough the importance of proper chain tension and alignment. It's all about those two things. Get them right and you won't have chain problems. This applies to any chain drive application. Be it in-frame or rack mount, 2 or 4 stroke engine.
Tom
i just read this thread and my thoughts on putting a bolt thru the frame, thru the tensioner works fine for me and i ride on cobble streets in mexico!! No problems with the frame yet and its been about 8months of riding. I am rebuilding my bike and i think a spring loaded one might be the way to go, especially with all the bumps i have to go on before i get to the main smoother road.
59Poncho; I made up a chain tensioner that goes between the seat and chain stay and I welded it in both positions. Needless to say, it never moves on me! I have a slot in it for the roller, as the orginal does that is supplied in the engine kits for chain adjustment. BMF
I just came across those ones and was amazed of the quality. Anybody seen those yet?
http://www.ebay.com/itm/motorized-b...Cycling_Parts_Accessories&hash=item4d04f9a4a6
http://www.ebay.com/itm/motorized-b...Cycling_Parts_Accessories&hash=item4d04f9a4a6
Those look really nice, I wonder if the spring makes the chain too tight?
The quality is there but a 40.00 part for a 100.00 engine is too high, 20.00 and seller would have a hit on their hands, as its needed for sure.
