Unusual tyre deflation

[Chad]

Just thought I'd share this with you all; last year a few of us were travelling through Germany along the Autobahns when noticed my mates triumph swaying & smoking. We were all traveling at around 110-120mph at this time so I pulled up along side him & urged him to pull over. His rear tyre was flat. We reinflated it and made our way to the nearest tyre centre. Suprisingly, no puncture found. No leak on the rim, nothing. We carried on with our trip but hey ho it went flag again. Again no leak found. 4 times this happened over 5 days. Fortunately, one of the fitters in one tyre centre was a biker himself. He took one look at the valve dust cap and said that's your problem; apparently in Germany dust caps MUST have a seal inside them, as when travelling at very high speeds on the autobahns the centrifugal force can be so great that it overwhelms the spring on some valves & thus releases the air! Naturally we all dismissed this as total BS but replaced the cap for a stainless one with the seal out of courtesy. No more flat tyres! If I hadn't have seen it I wouldn't have believed it. Moral of the story, if your mates are riding bikes at prolonged high speed with inward pointing valves on their wheels, just ride on when they have to pull over or you'll spent half your holiday in a garage:-)

[guest2360]

That's more reason for buying the LC. 

[David.]

http://www.amazon.com/BMW-Genuine-Motor ... B009IRG05A

[David.]

Thanks for the "Heads-Up", have just switched a steel valve stem cap complete with seal from my XJ650 to the rear wheel of the RT.

(I'm not likely to get up to 3 figures on the XJ650.)

The front wheel on the RT should be OK as the valve is on the side of a spoke & not exposed to the same centrifugal forces as the rear.