this tuesday i'm going from a 3.55 to a 4.56 ring and pinion and from a 245/75 to a 285/75 tire...my question is should i return my truck to stock, use the 89 tow, max perform, does it matter? thanks for all the help...i'm sure mike will get to this when he gets time...i bet he can type like 100wpm after replying to all of our posts

 

It doesn't matter which program you use if you change the effective gearing. All are affected equally in terms of tranmission shifting.

Now, you are increasing your tire size by 8% and increasing your gearing by 28%. That gives you an effective 20% more gearing which is too much IMHO. If you can change the gears still, a 4.11 would be a better match IMHO. Still improves effective gearing by 7% after the larger tire size.

Regardless, I would send your 9100 back to Troyer so he can change your calibration for gears and tire or you can expect some funny things to happen with 20% effective gearing difference.

 

i'll definitely give mike a call, i'm going to see about what kind of speedo gear i need (since it's a 98) to correct shifting and speedometer reading (so if anyone has a clue that would be great )...so i was just checking. i was kind of going for the effect that most get from just going to 4.10 gears with stock tires out of my bigger tires (not go back to stock)...my V6 can use all the help it can get. thanks guys

 

Then you got it the right idea with the speedo gear. I don't know if the Microtuner will care for 98, so others or Mike will have to help you there.

Is your truck auot or manual trans?

 

it's an auto...so that's really why i'm so concerned (could care less about the speedo...don't watch it anyway) about the shift points.