Guys who went to 35's . . .

[JWSchmidt3]

Are you having any issues with, or does it seem your transmission shifts at much different intervals than from stock?? I had an Adv. H3, and I am currently driving a 2007 dealer loaner while my lifted H3 is at the dealer, and my suspician is confirmed. One of the issues I sent the H3 in for is the tranny shifting. It always wants to shift down to low gear way too early. Is this because of the 35's?? Is there any way to properly calibrate the bigger tires?? My truck drives like a turd compared to thos '07. BTW, I also have a CAI and exhaust installed. Any help appreciated, as the dealership has yet to give me any real hope.

[HummBebe]

I think your only option at this time is to pay for it to be professionaly tuned.

GM has no computer re-program as of yet.

[meyergsr]

Your going to have to get your engine computer recalibrated for the taller tires the dealer wont do it. Go to the aftermarket like PCM for less. http://www.geocities.com/pcmforless/index.html

[JWSchmidt3]

Here's another issue, I bought the truck new from the dealer with this package installed (they call it the Xtreme Comp Pro package). The sales guy specifically said, "Oh yea, it's all been re-tuned for the bigger tires, intake and exhaust. They use the Tech-II". My extensive modding with Corvettes told me he was probably full of it, but I'm now holding them to it. I'm just curious if anyone else had such a drastic impact when they changed to 35's, or if I have another issue.

[CrisB]

You bought that H3 like that? The dealership probably did that themselves, somebody there thinks he knows what he's doing. I would definitely hold them to it, they built it.

[JWSchmidt3]

Originally Posted by Cris Burkhalter

You bought that H3 like that? The dealership probably did that themselves, somebody there thinks he knows what he's doing. I would definitely hold them to it, they built it.

Yes, but they contracted an offroad shop to do the package. The dealership is pretty reputable. I'll hold them to it, but the fact remains the PCM can not be properly calibrated for the bigger tires, and I'm wondering what other guys who have gone to 35's have done.

[HummBebe]

Originally Posted by JWSchmidt3

I'm wondering what other guys who have gone to 35's have done.

Wheel the hell out of it

[HummBebe]

Originally Posted by JWSchmidt3

Here's another issue, I bought the truck new from the dealer with this package installed (they call it the Xtreme Comp Pro package). The sales guy specifically said, "Oh yea, it's all been re-tuned for the bigger tires, intake and exhaust. They use the Tech-II". My extensive modding with Corvettes told me he was probably full of it, but I'm now holding them to it. I'm just curious if anyone else had such a drastic impact when they changed to 35's, or if I have another issue.

That is an outright lie. There is no Tech II program for tire increase to 35". Only from 32" to 33".

[JWSchmidt3]

Originally Posted by HummBebe

That is an outright lie. There is no Tech II program for tire increase to 35". Only from 32" to 33".

That's what I thought when I bought it, but was only 99% sure. I won't call someone out unless I'm 100%. Tomorrow I pick up the truck, and meet with the Hummer GM.

[Jeff G]

Originally Posted by JWSchmidt3

Are you having any issues with, or does it seem your transmission shifts at much different intervals than from stock?? I had an Adv. H3, and I am currently driving a 2007 dealer loaner while my lifted H3 is at the dealer, and my suspician is confirmed. One of the issues I sent the H3 in for is the tranny shifting. It always wants to shift down to low gear way too early. Is this because of the 35's?? Is there any way to properly calibrate the bigger tires?? My truck drives like a turd compared to thos '07. BTW, I also have a CAI and exhaust installed. Any help appreciated, as the dealership has yet to give me any real hope.

I've had mine installed for less than 24 hours and I would highly recommend the PCM for less tune. Totally different beast with the 35's.

[marin8703]

another quick question. The about 7% difference in the speedo between the 32 inch stock tire and the 35 inch toyos, is that a linear diffrence or exponential? By that I mean if your speedo shows 65, then you are actually going 70, is the same true if it shows 15 the actual is 20 mph, or would it be different?

Also do you think that this difference (speedo 7% slower tahn actual) is enough to throw off an aftermarket nav (pioneer avic z1) which uses the speed pulse in doing its calculations?

also i didnt understand if the pcmfor less calibration of the pcm can calibrate the speedo for the 35s, can someone clarify that? I know they ask what tire you are ising but do they actually configure teh speedo?

thanks

[JWSchmidt3]

Originally Posted by marin8703

also i didnt understand if the pcmfor less calibration of the pcm can calibrate the speedo for the 35s, can someone clarify that? I know they ask what tire you are ising but do they actually configure teh speedo?

thanks

Yes, they fix the speedo with their tune.

[HUMMJAY]

JWS- you've had the new pcm for a couple of months now,,, how's it working?? I've had 35's on my truck for about 9months and would love to get my milage and proformance back,,,, I'm on the verge of going back to 33's

[westhillsat]

Originally Posted by HUMMJAY

JWS- you've had the new pcm for a couple of months now,,, how's it working?? I've had 35's on my truck for about 9months and would love to get my milage and proformance back,,,, I'm on the verge of going back to 33's

My 75 cents worth.

I love the pcm change along with my dual exhaust from Jason
I got the Billy Boat exhaust

http://www.somo.com/

Average 12 - 13 mpg with the 35's, but have no acceleration issues now
and shifts great.

[JWSchmidt3]

Originally Posted by HUMMJAY

JWS- you've had the new pcm for a couple of months now,,, how's it working?? I've had 35's on my truck for about 9months and would love to get my milage and proformance back,,,, I'm on the verge of going back to 33's

Works great. Couldn't be happier.