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Re: Spare inner tube
Posted: Thu Jun 05, 2014 2:35 am
by corrado
90 degrees tubes work best but you need to check the clearance on the fork link nut on the front. Mypol ones are 55 degrees so usable on the rear and plenty of clearance on the front re the fork link bolt.
The term "Offset Valve" tends to confuse some people. The Mypol tubes have an offset valve, it means that the valve is offset from the centre line of the tube by 6mm. Most tubes have the valve [irrespective of valve angle] fitted on the centre line of the tube but on a Lambretta the hole in the rim for the tube is not in the centre so it makes sense that the valve shouldn't be either otherwise you're always pulling the valve to the side to get it through the hole which will cause unnecessary stress on the valve joint.
Re: Spare inner tube
Posted: Thu Jun 05, 2014 8:55 am
by Nerdy Norm
Thanks fellas!
An interesting point about the direction arrows on tyres. I've always thought that "front" and "rear" referred to the direction of travel, not which wheel they were fitted to. What would be the advantage of the tread pattern being different on the front wheel from the back? They both rotate the same way, so acceleration, braking and cornering forces would be the same surely?
Re: Spare inner tube
Posted: Thu Jun 05, 2014 10:41 am
by speedy
Nerdy Norm wrote:Thanks fellas!
An interesting point about the direction arrows on tyres. I've always thought that "front" and "rear" referred to the direction of travel, not which wheel they were fitted to. What would be the advantage of the tread pattern being different on the front wheel from the back? They both rotate the same way, so acceleration, braking and cornering forces would be the same surely?
Aha just one thing to think about there with tyres. Some tyres are front fitment only[ rare now, but there are], some tyres have the arrow for rotation,so you fit them with the arrow facing forward and some have an arrow that goes both ways, which are the ones where the front and rear go on the opposite way round. It does say front at one end of the arrow and rear at the other.cheers,Speedy.
Re: Spare inner tube
Posted: Thu Jun 05, 2014 10:54 am
by Nerdy Norm
More info here, which makes sense:
http://www.avon-tyres.co.uk/motorcycle/faqs
I'd better check mine when I get home
Re: Spare inner tube
Posted: Thu Jun 05, 2014 11:07 am
by warts
Producing a 1g force on the front tyre under braking should be feasible.
Producing a 1g force on the rear tyre under acceleration is some thing else entirely.
1g acceleration for 1/4 mile takes 9.08 secs, producing a terminal velocity of 198 MPH. (theoretically, but the sums may be off).
We debated some of the points covered in the Avon site a while ago.