View Full Version : Tire Rates and the ARB
AllenGeorge2008
12-16-2008, 12:42 AM
Hi.
I've been working on my calculations for the ARB installation.
However, I’ve kinda hit a road block; more precisely tire rates, which for the moment I do not have.
Without values for tire rates, it seems improbable that I would be able to come to a good enough conclusion for the ARB stiffness.
We’re planning to use Michelin 16/53-13.
It would be off great help if someone could pull me out of this. Say, even ballpark figures will be useful.
Thanks
AllenGeorge2008
12-16-2008, 12:42 AM
Hi.
I've been working on my calculations for the ARB installation.
However, I’ve kinda hit a road block; more precisely tire rates, which for the moment I do not have.
Without values for tire rates, it seems improbable that I would be able to come to a good enough conclusion for the ARB stiffness.
We’re planning to use Michelin 16/53-13.
It would be off great help if someone could pull me out of this. Say, even ballpark figures will be useful.
Thanks
Our first stab at an FSAE tyre was a two ply radial similar to Michelin. It had a rate of 123N/mm @ 40km/h and 1 deg camber.
Ben
AllenGeorge2008
12-16-2008, 12:51 AM
Thats a real big problem you've solved for me ben.
Thanks a lot..!
HenningO
12-16-2008, 02:10 AM
Ben, how much will the tire rate typically change with speed? I'm assuming it increases with increased speed?
Speed (km/h) Camber (deg) Pressure (bar) Spring Rate (N/mm)
40 1 0.5 67
40 1 0.75 84
40 1 1 107
40 3 0.5 67
40 3 0.75 84
40 3 1 96
80 1 0.5 67
80 1 0.75 87
80 1 1 110
80 3 0.5 65
80 3 0.75 84
80 3 1 101
Answer is not much in this case (our new 1 ply tyre), but the belt's very light. Percentages are higher for a GT tyre - I'll dig sdome data out.
Ben
HenningO
12-17-2008, 01:47 PM
Interesting numbers,
It struck me that I have never paid attention to how much camber affects the (vertical) tire rate. I'm guessing (once again!) it's highly dependent on the carcass design? If you have (and are willing to share), I'd be very interested in seeing what approximate numbers a typical GT/LMP tire have.
From this thread and the other about tire rates I can conclude the following (correct me if I'm wrong).
Vertical tire rate varies:
- Linearly with tire pressure
- With speed, the "heavier" the belt, the more it increases
- With camber, more camber=increased tire rate
More camber = lower spring rate
Ben
1.8 bar
Camber 100km/h 200km/h
0 358 379
2 324 340
4 274 284
2.0 bar
Camber 100km/h 200km/h
0 398 418
2 357 373
4 297 304
GT2 Customer rear tyre...
Ben
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