Author Topic: Question on Motorcycle Tire Growth at Speed and Ground Clearance and Fork Setup  (Read 2422 times)

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Offline fj1289

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Bottom line - how much clearance should I have between the rear tire and the nitrous bottle mount in front of it?  Tire is a 180/55 17 Bridgestone BT003 RS on a 5.5" wide rim.  Have been advised to run it at max pressure.   

Past posts seem to indicate 2" is about the min ground clearance with a fairly stiff suspension -- reasonably safe? Or would closer to 3" be smarter?

Forks are a set of upside down units off a 2000 Yamaha R1.  They've been internally lowered with 2" of travel remaining (lowered approx 3.5 - 4")  stock fork springs were not cut so they have a LOT of preload -- good for the drag strip...OK for the salt?  Or do I need to go back and cut the springs a bit?  Do I need any sag for handling/controllability on the salt?  Or is no rider sag a workable setup on the salt?

Thanks again for the advice -- trying to eliminate as many ignorant first timer decisions/mistakes as possible!



Offline nrhs sales

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is your rear rigid or does the bottle move with the suspension?  We see a suprisingly lot of suspension travel on our bike even with a 110 lb rider with the suspension set up quite stiff.  IMO you need at least 2 inches of suspension travel available up front and it using suspension in the rear set it up very stiff.

Offline fj1289

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Yes, do have suspension in the rear.  Using an old LinkPro adjustable linkage so have a pretty wide range of adjustment for the rear suspension.  Do you try to set up the rear suspension stiff enough to use 2" or less of travel during the run too?

Offline nrhs sales

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our rear suspension has about 3 inches of travel available and it uses all of it even with a light rider.  When you are hard on the throttle the rear will squat at least 1" to 2" with a big hp engine.  As I said set up the pre-load on the rear VERY stiff but have travel available.

Offline fj1289

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Thanks - will do!