Bushing durometer and rider’s weight.
Moderator: Terry Kirby
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Vlad Popov
- Moscow-Washington
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- Joined: Wed Aug 28, 2002 2:00 am
- Location: Moscow, Russia
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Bushing durometer and rider’s weight.
A 160-lbs rider prefers 82A bushings in the front truck. A 190-lbs rider insists on 84A as the softest bushing. Given that one unit of pressure is kg / m*second^2, and the bushings’ resistance is known, is it possible to calculate which rider has “adjusted” softer bushings?
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Eric Wallgren
- Geezer-X
- Posts: 67
- Joined: Tue Jan 07, 2003 1:00 am
If we're assuming a conventional 2 bushing type truck, the compression of the weight bearing bushing plus how much the bushings are preloaded needs to measured and accounted for. In addition, the degree to which the centering bushing is compressed during a turning cycle is dependent upon truck geometry and rider input. There are so many factors at play, I'm not sure where to start.
If you are using a PVD as an example, where the bushing is strictly a centering device, and for the purposes of argument are also assuming that the bushing has not been preloaded, then it's easy. Use a spring tester to determine the spring rate (oz/in) of the bushing in question, measure the deflection per degree of the truck and if it's linear, and multiply away.
and it's all independant of rider weight. A heavier rider is simply able to exert more force easily. A light rider with good unweighting/weighting skills can ride trucks with more RTC tension than a big rider who just turns.
If you are using a PVD as an example, where the bushing is strictly a centering device, and for the purposes of argument are also assuming that the bushing has not been preloaded, then it's easy. Use a spring tester to determine the spring rate (oz/in) of the bushing in question, measure the deflection per degree of the truck and if it's linear, and multiply away.
and it's all independant of rider weight. A heavier rider is simply able to exert more force easily. A light rider with good unweighting/weighting skills can ride trucks with more RTC tension than a big rider who just turns.