Technical > Roo Man's Room
Killer Tire shake Need Help.
rooman:
I agree with the "dead hook" assessment. That is a lot of tire to get slipping with 2500 rpm at the hit. Pump the tires up and / or lower the wheelie bar to get some wheel speed leaving (or do as Bruce suggests and put the right size wheel/tire package on the car). Bigger is not necessarily better.
Roo
masracingtd1167:
--- Quote from: dreracecar on August 10, 2015, 02:06:59 PM ---Rear motor top dragsters have different dynamics then a Front engine dragster
--- End quote ---
I understand that but they both need wheel speed to go from a to b and the Mickie Thompson tire that I suggested is narrower than the Hoosier I think the tread width is 14 1/2 wide but I think the big difference is the side wall with the same air pressure as the Hoosier they are much smoother .
ricardo1967:
--- Quote from: dreracecar on August 10, 2015, 02:06:59 PM ---Rear motor top dragsters have different dynamics then a Front engine dragster
--- End quote ---
Would it make sense to think that, for comparable tires shakes, it would be felt more strongly in a FED than in a RED?
dreracecar:
Has nothing to do with it. RE dragster has all the weight in front of the rear axle and further out along with a much stiffer chassie because the rails are further apart. Tire plants harder because the chassie is stiff, Try pushing down at the motor and see how much chassie flex, again at the rollcage, again at the front of the footbox. Now with a FE dragster the motor is out the same (relative), but nothing ahead of the motor and a fat ass driver counter-balencing the front weight by sitting behind the rear. Frame rails at the motor are narrower and the chassie will flex more. At the hit the tires are trying to drive under the engine on both cars, The FE will flex and arc in the middle to a point to where without enuff HP the flex will reverse itself and spring back unloading the rear tires, then tires catch up and frame flex/arc happens again, then guess what, back it goes into reverse and so on. If you have enough hp to maintain the arc till top HP is acheaved and carry it through its a good pass. A RE dragster does not flex as much so it does not unload the rear tires because the weight to the front is constant
ricardo1967:
--- Quote from: dreracecar on August 10, 2015, 05:37:36 PM ---Has nothing to do with it. RE dragster has all the weight in front of the rear axle and further out along with a much stiffer chassie because the rails are further apart. Tire plants harder because the chassie is stiff, Try pushing down at the motor and see how much chassie flex, again at the rollcage, again at the front of the footbox. Now with a FE dragster the motor is out the same (relative), but nothing ahead of the motor and a fat ass driver counter-balencing the front weight by sitting behind the rear. Frame rails at the motor are narrower and the chassie will flex more. At the hit the tires are trying to drive under the engine on both cars, The FE will flex and arc in the middle to a point to where without enuff HP the flex will reverse itself and spring back unloading the rear tires, then tires catch up and frame flex/arc happens again, then guess what, back it goes into reverse and so on. If you have enough hp to maintain the arc till top HP is acheaved and carry it through its a good pass. A RE dragster does not flex as much so it does not unload the rear tires because the weight to the front is constant
--- End quote ---
Thanks for the lesson Bruce. Keep 'em coming.
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