Final Chain Tensioner

[Janet]

Les, to add to my previous reply to you, from looking at some websites, it appears to me that people fit drive chain tensioners to cruiser style bikes, presumably because they have a long distance between the sprockets so get a lot of whip.

[G15 Roy]

Les, to add to my previous reply to you, from looking at some websites, it appears to me that people fit drive chain tensioners to cruiser style bikes, presumably because they have a long distance between the sprockets so get a lot of whip.

Janet there is the answer Les does suffer with a lot of whip.

[leswaller]

Les, to add to my previous reply to you, from looking at some websites, it appears to me that people fit drive chain tensioners to cruiser style bikes, presumably because they have a long distance between the sprockets so get a lot of whip.

Janet there is the answer Les does suffer with a lot of whip.

I didn't know you were into bondage Roy

[leswaller]

Spriddler is correct, it is the derailleur type tensioner I was thinking of as it would save the need to keep undoing the rear axle, screwing in the adjusters and readjusting the rear brake. All of which are a source of potential failure with our old bikes if subject to a lot of (mis)use.
If you look at modern trail and autocross bikes many of them now have this type of tensioner fitted, presumably as due to the stress on the chain with this type of activity they would need to adjust the back wheel after nearly every ride. They must be tough pieces of kit if they survive this kind of activity. In this month's Classic Motor Cycle Mechanics there is an article on how to make one, hence my question, 'has anyone tried it on our bikes"

[G15 Roy]

A modern motocross bike has a rear end travel of 8-10 inches if not more hence the need for a tensioner.

[leswaller]

A modern motocross bike has a rear end travel of 8-10 inches if not more hence the need for a tensioner.

Accepted, but that doesn't stop the technology being used on our bikes and it would save a bit of spannering. Also if the swing arm is correctly located relative to the axle it shouldn't in theory make any difference how long the travel is as the chain tension should remain the same at all points on the travel

[Janet]

A modern motocross bike has a rear end travel of 8-10 inches if not more hence the need for a tensioner.

Accepted, but that doesn't stop the technology being used on our bikes and it would save a bit of spannering. Also if the swing arm is correctly located relative to the axle it shouldn't in theory make any difference how long the travel is as the chain tension should remain the same at all points on the travel

Surely the tension in the chain changes as the wheel goes up and down because the swingarm pivots round a point on the frame that is further back the point, ie the gearbox sprocket, that the chain pivots round. I am happy to be corrected but that's the way my brain cell understands it.

[G15 Roy]

Ok this would make a good article for the Jampot Magazine so plenty of photos please. I could supply you with a good stock of swinging arms you could pre fit the tensioner and make a quid or two.

No advert implied Mr Advertising Clive, as these are only available to Les.


clive

[SPRIDDLER]

I was thinking of as it would save the need to keep undoing the rear axle, screwing in the adjusters and readjusting the rear brake.

TBH until riding my 350 became problematic I covered between 6,000 and 7,000 miles on it every year for 6 years (I distinctly remember that a new K70 rear tyre was also needed before each MOT) and don't recall a necessity for very frequent chain adjustment. It's not a powerful bike I grant you although I did ride it pretty hard up and down mountains etc. Maybe I was lax in my maintenance, perhaps I had better quality chains, lubed them fastidiously, or they were adjusted perfectly and without stress to start with. As far as I can recall most rear chain adjustments were necessary not as a result of chain wear or stretch
but (perhaps coincidentally and therefore unnoticed) due to adjusting the primary chain or fettling the clutch.
I do recall having to adjust and replace the chain frequently on my Greeves Hawkstone, but then I was mostly a tail-ender in all the mud and grit or dust and sand thrown up by those in front

[leswaller]

Roy,
If the gearbox final drive sprocket is in the same horizontal plane as the swinging arm pivot and they are very close to each other and the axle is fastened to the swinging arm then as the arm pivots it will perform an arc round the swinging arm pivot point and the nearby drive sprocket, and as the swinging arm is a fixed length the maximum difference in chain tension will be equivalent to half the distance between the pivot and the final drive sprocket centre