Hello!

I know the hight of the H2 is 81.7" with the opional roof rack crossbars, but how much hight would I gain if I put 36.8" tires insted of the stock. And, what's the hight difference with the air suspension, the lowest and the highest?

Hello!

I know the hight of the H2 is 81.7" with the opional roof rack crossbars, but how much hight would I gain if I put 36.8" tires insted of the stock. And, what's the hight difference with the air suspension, the lowest and the highest?

Okay, the formula for converting metric sizes to inches is:

(2 x Section Width x Aspect Ratio / 25.4) + Rim Diameter.

Stock H2 tires are 315/70-17

so

(2 x 315 x .70 / 25.4) + 17

= (630 x .70 / 25.4) + 17

= (441 / 25.4) + 17

= (17.36) + 17

= 34.36"

If you are contemplating 36.8" tires, your increase will be

36.8" - 34.35" = 2.45"

Since 1/2 of the change in tire size is above the axle and only 1/2 is between the axle and the ground, we divide by 2 to get the change,

2.45" / 2 = 1.23"

So, you would increase your overall height by 1.23"

If your 81.7" measurement is correct, your overall height with these new tires will be

81.7 + 1.23 = 82.93

or, IN THEORY, 83"

IN PRACTICE, many factors affect this including inflation pressure, temperature (how hot the tires are which is a function of how long they have been driven, among other things).

Also, since only the bottom half of the tire is load bearing, the formulae, which divide diameter by 2, are only approximations.

Conclusion? After using these crude calculations to see if you are even in the ballpark, you really need a very sharp spotter to check your clearance while you very slowly try maneuvering into and around your garage. Do this after COLD inflation to the pressure you normally use and after some heavy freeway driving on a hot day. Also, do it without anything heavy in the way of cargo in your vehicle and without passengers. These measures will hopefully avert any unhappy incidents.

The NOMINAL difference between lowered and raised positions using the air suspension is 2" at the rear axle. This will be slightly greater at the rear of the roof.

I hope this helps.

Nice job Tower!!! When in Hell did you find time to explain so thoroughly?

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by tower:
Okay, the formula for converting metric sizes to inches is:

(2 x Section Width x Aspect Ratio / 25.4) + Rim Diameter.

Stock H2 tires are 315/70-17

so

(2 x 315 x .70 / 25.4) + 17

= (630 x .70 / 25.4) + 17

= (441 / 25.4) + 17

= (17.36) + 17

= 34.36"

If you are contemplating 36.8" tires, your increase will be

36.8" - 34.35" = 2.45"

Since 1/2 of the change in tire size is above the axle and only 1/2 is between the axle and the ground, we divide by 2 to get the change,

2.45" / 2 = 1.23"

So, you would increase your overall height by 1.23"

If your 81.7" measurement is correct, your overall height with these new tires will be

81.7 + 1.23 = 82.93

or, IN THEORY, 83"

IN PRACTICE, many factors affect this including inflation pressure, temperature (how hot the tires are which is a function of how long they have been driven, among other things).

Also, since only the bottom half of the tire is load bearing, the formulae, which divide diameter by 2, are only approximations.

Conclusion? After using these crude calculations to see if you are even in the ballpark, you really need a very sharp spotter to check your clearance while you very slowly try maneuvering into and around your garage. Do this after COLD inflation to the pressure you normally use and after some heavy freeway driving on a hot day. Also, do it without anything heavy in the way of cargo in your vehicle and without passengers. These measures will hopefully avert any unhappy incidents.

The NOMINAL difference between lowered and raised positions using the air suspension is 2" at the rear axle. This will be slightly greater at the rear of the roof.

I hope this helps. </div></BLOCKQUOTE>

Thanks!!!

2+2=5

Thank you, Jerry. One of the rare benefits of occasional insomnia.

W1N, you are very welcome.