2nd Gen Non-Engine/Transmission the right gears for an auto with 35" tires

[LVJUNIOR]

They are BFG KM2's. The manufacturer says they are 34. 8" buat after hearing of others complaining they wer closer to 34" I measured mine at 33. 5" I ran my rpms using my gps as a spedometer and am closer to 2125rpm at 75mph. 4. 10 gears get me about 100rpm over stock 3. 54's and 3. 73's get me about 100rpm under stock 3. 54 gears at 75mph

 

[AH64ID]

The BFG KM2's are 598 rev/mile which rolls out at 33. 7, which is actually pretty tall for a 35, so I wouldn't complain.

Based on the math (which assumes a locked tq converter). With 4. 10's you would be 2115 rpms at 75, and with 4. 56s it would be 2350. So I would say you have 4. 10's.

35" KM2's and 4. 10's is like 3. 62's (assuming 245's stock).

 

[rivercat]

I say 4. 10s and I would love to swap with ya if you would split the cost or help do the swap. the 1900 number is for vp motors with your being a 12v its probobly more flexible if you time it right and adjust for the least amount of smoke and boost at cruising speed.

 

[RHestand]

AH64ID,
I'm home and have my notes in my hand:
My stock tires are 215/85/16 with a roll-out=92. 875". My math=682 revs/mile.
New 8R/19. 5s RO=106. 5" =595 revs/mile, and = about 8. 7% taller = about 3. 74 gear?
The only things I'm sure about are tire size and roll-out dimensions.
Would you check my math and get back to me?
TIA, Ray
PS. As best I could tell my GPS and MPH with the 215s was right on the money.

 

[AH64ID]

I get about 685 rev/mile from a couple mfgrs, so that math is good for the 215. What brand 8R19. 5's do you have, I have found them from 590-628 rev/mile, over a 2" difference in diameter.

But with your 595 calculation I show you at a 3. 57:1 equivalent. Your speedo should be 12. 7% slow.