37's or No 37's

[Gunzz]

Well I have been reading all your postings for a long time now, and have learned alot from you guys (and gals), when it comes to the H2, but now I am ready to play and not sure what to do.
First I live in South Jersey so there are not rock hills and big areas of wilderness like some of you have, and I AM very jealous. But there are beaches and sand pits, along with the ocassional Pines mud pit. So most of the time my truck is on the road. But I still like the look of more aggressive trucks and tires. So here are my questions.

1. Will a 37" tire fit on a stock rim and under a stock H2 with air ride without mods?

2. Will I lose alot of performance going with a 37"?

3. Will a 35" X 12.5 fit under the truck without rubbing?

4. How good is a Truex lift with air ride? What do you do to the rear air sensors?

I am really ready to do something but I don't want to go to the shops, I want to ask the experienced guys and get the real facts. Thanks

[SummitUp]

... I still like the look of more aggressive trucks and tires. So here are my questions.

1. Will a 37" tire fit on a stock rim and under a stock H2 with air ride without mods?
Yes, no problem. Don't go wider than 12.50" or you will experience serious rubbing on the stabilizer at full lock turns (you'll experience some rubbing even with 37X12.50's). It's a good idea to do a torsion key "lift."


2. Will I lose alot of performance going with a 37"?
Yes you will, but not a lot. Some will compensate by changing the differential gear ratios. Your speedometer will read low (read that getting a speeding ticket :( ). The only way you can recalibrate is with a programmer.


3. Will a 35" X 12.5 fit under the truck without rubbing?
This is the OEM tire size. BFG 315/70R17's are basically 35X12.5.


4. How good is a Truex lift with air ride? What do you do to the rear air sensors?
Truex? Do you mean <Truxxx> (http://truxxx.com/hummer_products/405020-hum.htm)? This is nothing more than a torsion key lift. It only lifts the front end and has nothing to do with your rear air suspension. You can purchase Chevy "green" keys from gmpartsdirect.com for $20.00 each (GM Part # 15592573) and achieve the same results. It's better to upgrade to longer shocks with more travel than to change the lower shock mounts just to keep the OEM shocks.

BTW the side by side comparison shown on the Truxxx site is really misleading... you can see at a glance that the yellow truck is so much taller because it has much bigger tires.

[Gunzz]

Thanks for the info Summit. I am not planning to regear if I go to 37's that was why I was wondering how much performance is really lost. I do have a programmer so correcting the speedo won't be a problem. I was really worried about the Truxx and how that will affect the rear air suspension and also the rubbing I will get with 37's.
So if I do the torsion bar keys and lift it a bit will there still be minor rubbing with 37's or will that small lift get rid of that problem?

Mike

[SummitUp]

The lift makes very little difference in the rubbing. The point of contact is the tires rubbing on the stabilizer bar when the steering is at full lock, and lifting the front end 2"-3" doesn't change this.

The problem lays in the fact that not all H2's are created equal when it comes to how far the tires will turn at full steering lock. There are variations in the the castings of the LCA's (lower control arms) and the spindle/steering knuckles used in various production runs on the GM assembly line. The steering stops are cast into these 2 parts and are not adjustable. This variation in the castings accounts for the fact that some H2 owners report that their stock OEM tires rub at full lock, while others mount 37's on their trucks and experience no rubbing at all.

If wider tires than 12.50's are mounted it really becomes a problem and they they can also rub on the inside of the fender well (usually on the rear of the well).

The real point of the torsion key lift is to level the truck out (the H2 has a fair rake to it... front is lower than the rear), and gain more ground clearance in the front.

[HUMMERcustoms.com/TAZ]

Performance is loss is not a sure thing because most of the time you are traveling at lower speed and lower tranny gear. When off road use tow haul button allot and it increases line pressure and allows the gears to stay in for longer RPM.

If real unhappy gain HP/tor with electric fans and even can gain 10to 15 hp with electric water pump. Many minor things can be done befor going to a supercharger. In fact gear ratio change would cost allot less than SC.
Good luck,

TAZ

[H2Much]

Gunzz, if you do go 37's, you will want to have it re-geared. If anything, to make it easier on the tranny. Iv'e noticed with my 37's, I have issues with it downshifting in and out of overdrive around 75 mph. I have also noticed that in the lower speeds, going up hills or inclines, that it pushes up to 5000 rpm's, and you can feel how hard the car works when shifting. Really, it is much cheaper to just regear it, and it will ride the way it should without working your tranny too much, definetely the better choice over time in the long run. Be sure to look into everything before going with a lift, as you will run into serious issues with the airride, just like I have.

[Gunzz]

Well thanks for the replies. Maybe I will forget the 37's and stick with the 35's and have less to worry about. If it wasn't my everyday driver I would definately go for the 37's but since it is guess for my needs the 35's will be fine. I don't even want to think about regearing etc.., since I am in warranty and do not want to void any of that.

So mud terrain 35's should do me fine. Thanks again :clapping:

[Kuuner]

Well I have been reading all your postings for a long time now, and have learned alot from you guys (and gals), when it comes to the H2, but now I am ready to play and not sure what to do.
First I live in South Jersey so there are not rock hills and big areas of wilderness like some of you have, and I AM very jealous. But there are beaches and sand pits, along with the ocassional Pines mud pit. So most of the time my truck is on the road. But I still like the look of more aggressive trucks and tires. So here are my questions.

1. Will a 37" tire fit on a stock rim and under a stock H2 with air ride without mods?

2. Will I lose alot of performance going with a 37"?

3. Will a 35" X 12.5 fit under the truck without rubbing?

4. How good is a Truex lift with air ride? What do you do to the rear air sensors?

I am really ready to do something but I don't want to go to the shops, I want to ask the experienced guys and get the real facts. Thanks

Performance? I get Hundai's honking at me to pull over so they could pass me with my 37's. Performance is not something I would say it has...unless you are talking off-road. Make sure you tweak your torsion bars or you WILL rub.

[kalantar]

I have 37.5x 13.5 on 20's, they tweaked the front torsion bars a bit to make it fit and I love the way it looks now. The car's look is night and day difference. I didnt regear, there wasnt a need for it since I always drove slow and didnt tow much. Now that I am looking into towing a 7,000 lb trailer I might get it done, still not sure. Any ideas on the cost? The speedo is off a bit, but power is fine. Breaking is a bit softer, but again it has been worth it. I get tons of compliments on the car. MPG did decrease to 9.5 in city driving, but again completely worth it.

[Rene S. Nielsen]

Wow Kalantar

That setup looks great.

Do you have anymore pictures. (didn't do a search from them)

What brand are those tires and rims.

Looking exelent :perfect10s:


Regards
Rene

[kalantar]

http://www.elcovaforums.com/forums/showthread.php?t=33433

I dont have the rear air suspension, so that is why 13.5 fit on my h2.

[Gunzz]

http://www.elcovaforums.com/forums/showthread.php?t=33433

I dont have the rear air suspension, so that is why 13.5 fit on my h2.

Truck looks great. So since I have the air suspension I couldn't run this setup?

[DDWH]

Truck looks great. So since I have the air suspension I couldn't run this setup?

37x12.5x17 and your all good. If you go with a 13.5 your going to have to modify your air ride sensor arms. There is a thread on someone that did it, with full details and pictures. Try the search, I don't remember who it was.

I have 37x12.5x17 Cooper Discoverer STT with no issues, minor rubbing at full lock, which is normal for everyone that has gone to 37's.

[SnakeH2]

I have 37x12.5x17 Cooper Discoverer STT with no issues, minor rubbing at full lock, which is normal for everyone that has gone to 37's.

Just put in an order for those. Installed for $1,200. I'm guessing you've been happy with them. Are you frequently rotating them? Are you happy with the wear?

Snake

[kalantar]

12.5 you should be fine, look at my other posts on the type of tires I use..