Landracing Forum
Tech Information => Steering - Suspension - Rear End => Topic started by: Rooney on February 25, 2012, 12:28:35 AM
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On a suspended bike would the ballast be mounted to the swingarm or frame?the rule book says"ie bolted to the frame structure".I have heard people talk about lead on theyre swing arm.
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Yes... mounted anywhere and everywhere you can. One the 1000 we had 68 lbs of lead inside the swingarm, 15 behind the engine, 20 behind the front fairing mount, 30 in the tail section, 30 on each side outside the swingarm and of course 215 on the seat :-D
Slip was 1 to 7% depending on salt conditions, about 2 on the record runs.
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never go beyond 60/40 weight bias at the wheels, or handleing will become an issue,,, when setting up, i take the bike to our local dragstrip where thay have a set of digital scales, and take readings with the rider fully suited in the prefered tuck position,, its interesting to see the difference (weight) at the wheels that moving your body six inches back or forward can make,,,
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20# on either side of the swingarm and 30# at the front of the 'arm (where the nitrous bottle used to be mounted) = 70#. Speed without the ballast = 200, speed w/ballast = 207.
However -- sure enough, both Nancy and I had some tank-slapper issues at about 160 MPH then - so we had to soften the rebound on the rear shock -- was squatting down too much, mostly from the bumpy salt. Squat down = altered rake angle = lousy stability.
Make sure you read the ballast rules carefully - no more can it be behind the rear axle, for instance. In production it cannot be visible.
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I run about 80# in the swing arm. As the speeds have gone over 220 the handling has gotten a bit twitchy. I am going to put about 30# on the front of the bike this year.