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The price of lightweight balloons
When even a puttering randonneur gets up into the big bikes and the
big balloon tyres, he suddenly acquires something in common with the leanest roadie on the skinniest tyres: he becomes a weigh weenie. For instance, in the biggest size, 50-622, going from the 995gr Big Apple to the 790g Big Apple Liteskin saves seven and a quarter ounces, or damn nearly a pound between a pair of tyres. Someone else will have to say if you lose anything in comfort or puncture-proofing or durability by going from the standard Big Apple to the Liteskin. I've only had the Liteskin. In tubes the weight saving is even more. Going from the 220gr Schwalbe Type 19 standard tube suitable for Big Apples to the 140gr lightweight tube Type 19a saves three whole ounces per tube. Between the lightweight tyres and the lightweight tubes then, one saves a pound and a quarter per bike (no spares carried! -- nearer a pound and a half if a single spare tube is carried). But there is a price. It probably isn't much to a racer who checks the inflation of his tyres before every ride. But it matters, though probably not too much, to the utility/recreation biker one finds on balloons. It turns out that the extra light tubes are more permeable. They lose air more quickly. Whereas it is perfectly okay to check the inflation in a standard Big Apple with the standard Schwalbe T19 tube every month or even every two months in the certain knowledge that it won't lose enough air by natural processes to go out of bounds (unless run on the very lower limit, of course), the lightweight T19A tubed tyre's inflation must be checked every fortnight, more often if you run them closer to the lower limit of inflation. After some experimentation, I have settled at running my Big Apple Liteskins with the Type 19A lightweight tubes at 2 bar front and rear. That gives one enough comfort and plenty of control if precision is required in steering or handling. This is a bit higher than was initially reported by Lou and also by me: I've gone for the slightly higher inflation to give me a (perhaps merely psychological) margin of error against snakebites for the occasional pothole taken at speed while talking to the pedalpals. Starting from 2 bar, weather cool and tyres lightly used (only short fast sections) and thus unlikely ever to be hot for long, the T19A lightweight Schwalbe tube self-deinflates to 1.9 bar in a fortnight and 1.8 bar in three weeks. The permissible minimum inflation for the 60-622 Big Apples is 1.5 bar, so this is a pretty fat safety margin if you let the inflation check go another week or fortnight. Andre Jute It's not talent that makes you (fill in whatever you want to be), it is persistent attention to detail |
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