capitalx
June 28th, 2015, 03:04 AM
Facts:
GMT800 Hummer H2
Duramax LBZ / Allison 1000 6spd
37" Tires
H2 Final Drive 410
Duramax donor had 373
Issue:
I'm trying to do a tire size adjustment in order to correct my speedo. Initially speedo was of 9mph at 70 cruise. It was reading faster than GPS speed. I use the Speedo Calculator and determined that 36.8" tires height was 548.05 rev/mile. (Tire manufacture says 565) After adjusting I was within 6mph off. Tried and tried and nothing helped. out of desperation, I began a series of flashes with different values I ended up with 604 rev/mile which according to the calculator is a 33.3" Tire.
Why this odd behavior and what else is being thrown off by correcting my speedo.
GMT800 Hummer H2
Duramax LBZ / Allison 1000 6spd
37" Tires
H2 Final Drive 410
Duramax donor had 373
Issue:
I'm trying to do a tire size adjustment in order to correct my speedo. Initially speedo was of 9mph at 70 cruise. It was reading faster than GPS speed. I use the Speedo Calculator and determined that 36.8" tires height was 548.05 rev/mile. (Tire manufacture says 565) After adjusting I was within 6mph off. Tried and tried and nothing helped. out of desperation, I began a series of flashes with different values I ended up with 604 rev/mile which according to the calculator is a 33.3" Tire.
Why this odd behavior and what else is being thrown off by correcting my speedo.