H3 Alpha on 32s Vs. 35s Acceleration

[amrg]

I always wondered how much a difference in acceleration bigger tires did on the truck, so I decided to measure 0-60 before swapping in my 35s on 17s and compare it to afterwards. I did both runs on on empty deserted side street, and 1 hour in between.

I have an SA model alpha, over here they come with 32s (instead of 33s as in the States), so acceleration figures should be higher than what you guys are used to for stock tire size.

Stock 32s run, 0-60:



Second run on 315/70r17, speedo corrected offcourse:



Ive done a similar thing on the I5. The difference there was almost 2 seconds.

Btw I don't race my truck, I wheel it :horns:

 

[High Five H2]

that's interesting... how about gas mileage? did you track that with the 32s?

 

[3Hummers]

Didn't track mine but did have a noticeable difference when I went to 35" tires.

 

[amrg]

I tracked mine, Im a site engineer and drive alot from one site to another, my company compensates me for fuel. I used to get 15 mpg (lots of highway) on 32s. Now I get 13.4 mpg (avg. Of 8 full tanks)

I do roughly 60 miles a day 45 of em highway, highway speed of aprox 70 mph. Inside the city approx 20mph...

 

[06 H3]

less then a second difference for the alpha?

 

[LagunaH1]

Didn't track mine but did have a noticeable difference when I went to 35" tires.

I remember the same happening to mine when I went from 33 to 35

 

[amrg]

less then a second difference for the alpha?

Id say 1 second. I manually shifted the Auto trans from 1st to 2nd on both runs. Forgot to mention I did both tests twice, first without manually shifting from 1st to 2nd, and the truck was 0.3 seconds slower on 32s, 0.4 seconds on 35s. (The truck shifts roughly 300 rpms earlier than the red line at full throttle). Im assuming a tune fixes this?


Btw on hot days when temps are above 100 degrees I remember the difference was much more, so I was overly impressed today.

 

[2010H3TAlpha]

Great comparison, thanks for posting this. Sorry if I missed this somewhere, are you on a stock or modified tune?

 

[amrg]

Completely stock at the pcm. Running a k&n oil filter + gm performance exhaust on the truck.

 

[4speedfunk]

I'm running 37"s & 5.13s with a PCM tune. This combo works good and the truck is surprisingly quick from 0 to 30 mph (compared to stock). The shifts come hard & fast, and it takes a few drives before you train your foot to be more sensitive on the throttle...especially right at take-off. The gear reduction is so drastic that the increased torque over-powers the rear springs and I've got some minor axle-wrap issues. I'll be addressing this with a torque arm after the weather gets warmer. Its most noticeable right at take-off, especially in low range.

Don't be too quick to rip on the 5-cyl's power....it just needs gears! Cruising rpm is 2400 at 65 mph. Mileage is (gulp) low 13s.

Low-range (4:1) can only be described as "other worldly". I've ridden in some pretty tweeked-out Jeeps (trailered rigs of course) but, I've never had a vehicle that has this crawl ratio, that can also hit the freeway all day at 70 mph. You just have to make sure you stop and gas-up every 2-hours!