Tire Rates and the ARB

[AllenGeorge2008]

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]

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

[ben]

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]

Thats a real big problem you've solved for me ben.
Thanks a lot..!

[HenningO]

Ben, how much will the tire rate typically change with speed? I'm assuming it increases with increased speed?

[ben]

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]

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

[ben]

More camber = lower spring rate

Ben

[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