Tire size questions

[AZhummer]

Hi All, I have a question. I would like to get larger tires. 37's ( 36 really ) I wonder if one of you guys who have this size on there H2 can give me the low down. Is the rear end ratio change noticable? Goes from 410 to 390. Is the highway handling and stability different? What do you think?

03 H2

[AZhummer]

Hi All, I have a question. I would like to get larger tires. 37's ( 36 really ) I wonder if one of you guys who have this size on there H2 can give me the low down. Is the rear end ratio change noticable? Goes from 410 to 390. Is the highway handling and stability different? What do you think?

03 H2

[Bevo]

Actually, going from stock 35's to 37's changes the ratio the other way... s/b from 4.10 to around 4.33. 37/35*4.10=~4.33...

[This message was edited by bevo on 02-21-04 at 04:11 AM.]

[This message was edited by bevo on 02-21-04 at 04:12 AM.]

[AZhummer]

I think the formula is old size/ new size. Not new size/old size.

03 H2

[KenP]

At 60 mph you will be going 63.4 with 37" diameter tires.
http://www.chrismans.com/Calculators.html

And this from http://www.4x4connection.com/gearchart.htm
:
According to this chart, the acceptable RPM range is 2000-3000 which is represented by the entire shaded area of the chart. The optimum RPM range is 2300-2600, and is represented by the light yellow shading. When changing ratios to improve mileage, choose a ratio within the dark yellow shaded band below the optimum range.

Black Lingenfelter Lux

[Bevo]

AZ,
Check out the link to Crismans that KenP mentions in his post. They have several online calculators that will help you out.

[Navigator]

I remember reading a very good (long) detailed post about this it may have been from Mac, I could not find it with the search though. Maybe someone else will remember it.

Rich

04 H2 Adventure Series

[PARAGON]

Rich,

You've gotta be kidding. Mac writing an informational post about something technical. Impossible!

[AZhummer]

Bevo, you are correct, I don't know where I saw that other formula. Wow 4.33 would give better acceleration and the increase in speed would in effect give the same results as the stock tire size. But you will gain 1 inch diff clearance. That is my goal.

03 H2

[Apex IV]

I have 37 x 13.50 x 17's on one of my H2's, 37 x 12.50 x 17's on another and the other two have stocker tires. The 37 x 13.5's are about an inch and a half taller than the BFG 37 x 12.50's and about that much wider. I've been out of the country for a while, which is why I have not been able to post, but if you search by my user name (apex4), you may find some pictures I posted when I installed the 13.50's. I live in a moderately hilly area, so I notice the change in "effective" gear ratio with both of the 37's - more so on the 13.50's (they are actually taller than the BFG 37's and wider, so they also weigh considerably more.) We did the intake/chip/exhaust on all four H2's and that helped some, but not enough on the ones with 37's. Ended up supercharging one with the larger tires and one with the stockers - Big improvement and about 3 mpg better on the one with 37 x 13.50's. Slight decrease on the one with stock tires. Both more fun to drive... :-)

Hope this helps!

-Randall Garrett-
Apex Software

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[It\'s a Dry Heat]

Warranty policy per Doug Hamlin at AMG:

BODY LIFTS: will not void your factory warranty BUT a body lift will "red flag" your truck, so any warranty issue will be reviewed and IF it is determined that the body lift had anything to do with your warranty claim, it will be denied.......the factory claimed that a lift increases "body roll" and the center of gravity...thus......claims on idler/pitman/ball joints/t-case/ect....you may be in for a "debate" with the factory

MILE MARKER HYDRAULIC WINCHES: AMG will NOT pay for warranty claims on the P.S. pump, the steering gear box, or the hydra boost if you have the MM-hydraulic winch.

TIRES over 37 inches: same thing, a debate if they think the tires are related to the claim.

Warranty policy per Doug Hamlin at AMG:

BODY LIFTS: will not void your factory warranty BUT a body lift will "red flag" your truck, so any warranty issue will be reviewed and IF it is determined that the body lift had anything to do with your warranty claim, it will be denied.......the factory claimed that a lift increases "body roll" and the center of gravity...thus......claims on idler/pitman/ball joints/t-case/ect....you may be in for a "debate" with the factory

MILE MARKER HYDRAULIC WINCHES: AMG will NOT pay for warranty claims on the P.S. pump, the steering gear box, or the hydra boost if you have the MM-hydraulic winch.

TIRES over 37 inches: same thing, a debate if they think the tires are related to the claim.

Warranty policy per Doug Hamlin at AMG:

BODY LIFTS: will not void your factory warranty BUT a body lift will "red flag" your truck, so any warranty issue will be reviewed and IF it is determined that the body lift had anything to do with your warranty claim, it will be denied.......the factory claimed that a lift increases "body roll" and the center of gravity...thus......claims on idler/pitman/ball joints/t-case/ect....you may be in for a "debate" with the factory

MILE MARKER HYDRAULIC WINCHES: AMG will NOT pay for warranty claims on the P.S. pump, the steering gear box, or the hydra boost if you have the MM-hydraulic winch.

TIRES over 37 inches: same thing, a debate if they think the tires are related to the claim.

Vern

04 Yel H2, F&R Eaton lockers, SMA HD brush guard, XD9000i, Auto Start. Garmin StreetPilot 3.