Hummers with 37's need help
 

08 H2 and needs tire

I like the look of 37's but have concerns over loss of power due to tire size

whats your experience?

thanks Neal

On my 05 I switched from 35's to 37's and if there is a loss of power it must be minor since I don't feel it

mcioci, thanks for the reply, leaning towards the 37's

There shouldn't be that big of a difference. Not like you're going from 35's to 44's or something insane.

I have an 08 w/ 37's (the metric version 325/60r20) and regeared to 4.56. We tow with ours and it made a huge difference both towing and not towing. Wish I would have done it sooner. The 08's have 3.73 gears and the rpm is too low but it has a 6 speed tranny where as previous years only 4 speed. So 4.56 isn't so limiting for us.

I looked at the BF Goodrich in that size,

what brand tires are you running?

How did it perform when not towing your trailer?

thanks Neal

I thought about that but sometimes a little can make a big difference

Thanks Neal

The biggest complaint in the past of everyone going 37's was the change in the speedo which can be fixed with a tuner. Gas mileage is non-existent in an H2 to begin with so going 37's wouldn't be a particular concern of mine. My concern would be fitting it in my garage with my roof rack and 37's. After the level kit I only have about a 1/2" of clearance now.

I can't speak to 325/60r20s, but it's been well documented that the BFG KO2s are undersized. 35/12.5r17s run 33.5 & the 37/12.5r17s run 35.5".

Here's my before and after discussion w/ the 4.56 gears on an 08. Long story short, I have not idea why the H2 didn't come w/ at least 4.10's

https://www.hummerforums.com/forum/h...-towing-37067/

and yes my my 325's measure just over 35" aired up and weighted. I've never had a set of 35's that measured 35" either. So in my mind 325's are the true 35" tire. I suspect 37's measure 35" as well.