Bigger Tires

hanrock · January 26, 2011

hi i just purchased an 08 2500 hd and installed 265 75 16 instead of 245's is it worth getting the dealer to re program if they do will it change more than the spedo eg. shift points ect. i noticed a diference in how it shifted after install . i'm going to get them to reset the tire press sensors to 50 psi on all four so i can run less air press. 55 ish and more when i need it and its not such a pain to rotate so should i do this while its in the shop if tire size efects only the spedo then its not an issue any and all oppinions welcome thanx

8.1HD/ALLISON · January 26, 2011

I would. Only takes a minute with the scan tool. Having to constantly remember how much your speedo is off is a pain in the a$$ IMO.

cliobogger · January 27, 2011

for the price you're going to pay the stealership to do this all for you, you could just pay a hundred or so more to get it tuned by justin at blackbear. he can change ur shift points, reporgram for tires, get all the gm nannys out of the way for you and you will love the tune. look into it.

dewfpo · January 27, 2011

I can't speak for your '08, but when I switched from 245's to 265's on my '05 the speedometer became dead on accurate. Before (with the 245's) it read faster than actual.

DEWFPO

chaser841 · January 27, 2011

I can't speak for your '08, but when I switched from 245's to 265's on my '05 the speedometer became dead on accurate. Before (with the 245's) it read faster than actual.

DEWFPO

Same thing with me going from 245 to 265.

burnthefurniture · January 27, 2011

I can't speak for your '08, but when I switched from 245's to 265's on my '05 the speedometer became dead on accurate. Before (with the 245's) it read faster than actual.

DEWFPO

Same thing with me going from 245 to 265.

Likewise, but I think I need 285's for mine to be dead on.

rocksolid · January 27, 2011

What are you guys using to calculate your MPH, GPS?

dewfpo · January 27, 2011

What are you guys using to calculate your MPH, GPS?

Around here there are numerous highway DOT & local police radar gun MPH warning signs showing your speed. They all seem to be consistent with each other so I go by them.

DEWFPO

Mike2500HD · January 29, 2011

What are you guys using to calculate your MPH, GPS?

Around here there are numerous highway DOT & local police radar gun MPH warning signs showing your speed. They all seem to be consistent with each other so I go by them.

DEWFPO

Yup, I went from the 245's to 265's and went by the local radar sign... dead on. Save your money.

Prokopchuk_9 · January 31, 2011

What are you guys using to calculate your MPH, GPS?

Around here there are numerous highway DOT & local police radar gun MPH warning signs showing your speed. They all seem to be consistent with each other so I go by them.

DEWFPO

Yup, I went from the 245's to 265's and went by the local radar sign... dead on. Save your money.

if you had an iphone there is an APP for that

thats wut i used we checked it against my actual GPS and it was spot on....i wouldnt trust any of those radars along side of the road. i know my speedo is spot on and ive drove by those things many times and they are off. sometimes those things sit on the side of the road for months without being calibrated. (best way to get yourself out of a speeding ticket) if the cop cant produce the legal document showing calibrations and the start of the shift, middle and end of that day. you got out of a ticket. worked for me. just thought i would share...