Landracing Forum
Tech Information => Technical Discussion => Topic started by: Mandi Engineering on October 21, 2014, 07:09:46 PM
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Since my chassis is a hard tail for the motorcycle, I am at the step to create a seat. I am unsure if I should go the rigid style or pivot/springer style...any advise would be great.
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Pretty difficult to give any sort of recommendation without pictures of the bike we're dealing with. :-( :-( :?
Pete
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no seat at all will get you the lowest
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If you need help/advice on making a seat pan for your hardtail I have lots of pics of both flat and springer step by step fabrication.
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you won't need any type of suspension on an LSR seat.
bf262
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Please, anyone, correct me if I'm wrong here . . .
From an aerodynamic standpoint, doesn't it make sense to have your hips higher,
instead of lower, such that the profile of your back (viewed from the side) is
less steep? I've been led to believe that this will promote smoother airflow and
less vacuum behind the rider, and therefore less drag, compared to having a
lower seat.
If this is true, then it suggests that a thicker (higher) seat cushion would be
advantageous. Therefore, more padding is good, and may help increase comfort
for the rider. A thick and soft-enough seat cushion may replace the need for
(metal) springs in or under the seat itself, if the bike has a "rigid" frame with no
rear suspension.
tallguy
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A trick used in road racing is to crouch down over the bars and to raise one's butt till the back is level. This gives a few extra miles an hour on the straight sections.
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My experience has shown that when I try to modify the angle of my back/butt while goinng down the course - by standing on the pegs so I can raise or lower my hind-end -- is that there's a trade off that is visible on the tach. That is -- when I start to lift myself off the seat pad and put my weight on the pegs, the resulting change in weight distribution on the bike results in less mass on the rear wheel and the tire spins up. does that mean I'm going faster -- or is it wheel spin. For the most part, dang it, it's the latter -- excess wheelspin. Conversely, when I get my butt back down on the pad the wheelspin is reduced, but my aero isn't quite as good. The wheelspin goes away but the speed doesn't increase.
Without an accurate speedometer it's difficult to quantify this, but a bunch of runs have shown me that the aero improvement doesn't bring about higher speeds. Your results may not be the same. My bikes run in the low 200 HP range. With lower power you may have different results.