xxxtreme22r

Not sure if I am doing this right. Brain isn't working today I guess. Wanting some confirmation or a smack on the head for being a noob.

1988 FSM (page 869 & 1390) lists my truck (RN61-MRA) as having a ride height measurement to the LCA bushing bolt of 11.22" and a rear measurement to the Leaf Spring Hanger bolt of 17.913. All with a factory tire size of 225/75R15.

Now the differece between a 225/75R15 (28.28") and a 31X10.5R15 (30.97) tire in overall height is 2.69" according to 1010tires. Divide this by 2 and it should give the change in height of the truck with the 31's which is 1.345".

Which means adding 1.325" to the front and rear FSM measurements (11.22" & 17.913") should give me the new specs for Factory ride height.

Conclusion Front ride height should be 12.565 & 19.258 Front/rear respectively.

The reason why I am doing this is because there is a question wether or not my front torsions are cranked down due to the truck being in a previous accident and the P.O. had them cranked down to level the truck due to rear spring sag.

Now here is why I am doubting myself. Measuring the front I get about 11.5" which is about 1" inch lower then my above compensation numbers. Rear is measuring 17.5 about 1.75" lower then where it should be based on my math.

So what I am looking for is basically someone to either confirm my math is right, or maybe your own measurements of a factory truck with 31's. I would assume it doesn't have to be one with factory 31's.

Another thing that throws me off is I know these trucks also came with a 31" tire option and none of those numbers on any of the frame codes measure even close to what I am getting and only range between 11.102 and 11.398. Does the FSM not include the trucks with the 31" tire option?

waskillywabbit

iTrader: (-1)

:wabbit2:

xxxtreme22r

owwwww. silly wabbit.

sebastianholmes

measure your tires to make sure theyre actually 31 inches, i doubt they are

xxxtreme22r

Good point. I don't know why they just didn't give ride height measurements between the fender and the 15" rim. Or include the 31" tire option in the FSM.

Yes I know 4crawler or someone mentions 13 or 14" or something like that but that's an 89-95 which is different then the 86-88.