Heres the deal,
i have 325/65/18's and i just regeard to 4.56's, just got done putting it back together and took it for a test drive. Everything worked great but i have some questions and i wanna hear some testimonials from you guys who have done the same or anyone else that has any imput at all..

1. With 35" tires and 4.56 gears, what percentage is my speedometer off by roughly?
2. Anyone else with a similar setup feel like 4.56's are too low? i feel like i am staying at a high rpm compared to what i was before, or maybe i am just used to my 33" tires and stock gears?
3. what average fuel economy are you guys seeing? I do mostly city driving, use the gf's mazda 3 for hiway

thanks for your imput its much appreciated!

 

What was the original ratio, and what size tires did the truck come with from the factory?

 

stock was 3.55's and i believe stock tire was a 275/65/18? not positive now i dont remember its been so long now. after that i went to a 325/60/18 with stock gears, then 325/65/18's with stock gears for about 2 weeks and then i just regeard.
for whatever reason when i test drove it, it never shifted into overdrive. i have no idea why, and it didn't for a while after that. later that night when i went out though it did and then it was great in town and so far its doing a lot better. so that eliminated some of my worries about the high rpms.

 

275-65-18's are 32's.

http://www.4lo.com/calc/gearratio.htm

I used 3000 RPM in 3rd, when the speedo says 68.5, you are doing 80.5. That's a 19% error.