Ever since H3 Hummer obsession took hold of me, I have seen many people visit my site searching what’s the biggest tires an H3 Hummer can fit and whether or not it is possible to put 35-inch tires on an H3 Hummer. The answer is surprising, “Yes, thirty-five-inch tires will fit on an H3 Hummer that is completely factory.” Even the factory tire mount on the tailgate will fit a 35″ tire just fine. There are however few things to know when mounting tires that big on the H3, but overall, it is completely worth it.
The biggest tire that will fit without any modification to the vehicle is 315/75r16 which is 34.6 inches tall and about 11 inches wide. Even though the tires are only 34.6 inches at the tallest, they are considered 35’s in the off-road world. The tire I decided to go with is the General Grabber 315/75r16 because I wanted a tire that was aggressive but had relatively no impact on tire noise, gas mileage, and high-speed handling when compared to the factory tires. To my surprise, when I finally came face to face with the tires I found them to be more aggressive than I had expected. However, while they are more aggressive than I was expecting, I have had my expectations for the tires exceeded. The road noise isn’t an issue, gas mileage seems to be right on, and while they handle differently it is only because of the extra grip these tires have. Even though the tire size has changed, the speedometer is still for the most part right where it should be. Typically, H3 Hummers with 35-inch tires speedometers are only 2-3% slower than the actual speed of the vehicle.
The Factory tires that H3 Hummer comes equipped with are lighter load range than most typical off-road tires and this has some positive effects and negatives ones too. Higher load range tires can handle more physical weight than a lower load range tire can and as a result, they weigh more and affect the gas mileage negatively. Typically city driving is where you will see the difference in gas mileage, where as highway mileage should go nearly unnoticed. How much this affects the gas mileage is entirely up to the driver, varying widely from driver to driver, and resulting in no easy way to calculate the change. Since these tires can handle more weight, the tire itself doesn’t absorb as many vibrations and can cause the Hummer to ride rougher than normal. Luckily with my tires at 35 PSI, I haven’t been able to tell for certain if the ride is rougher or just the same.
On the positive side of things, a higher load range tire is great for what it was intended to do in our case, driving off-road. The first thing everyone should do before some serious off-road driving is air the tires down. How much is debatable, but I typically choose 12 to 14 PSI. The reason for airing down is to increase the amount of traction the tire has and make the trails easier on the driver and more importantly the vehicle. The higher load range helps hold the bead of the tire on the rim at these lower pressures when off-road. If the bead were to slip it can cause the tire to become unbalanced, or typically what most worry about is letting out all the tire pressure. Once the trail ends or the decision to return to civilization is made, typically you have driven a while before you find a pump to return tire pressure back to normal. Forcing the driver to drive the nearest gas station to return the tire to a safe PSI. Driving on low tire pressure is less of concern with higher load range tire because of the extra strength that the tire has. Of course, the biggest, and the only reason to ever consider putting a bigger tire is to increase the ground clearance on the vehicle.
Overall, I’m happy with my General Grabber tires so far, gives the aggressive look I wanted, and I look forward to seeing how well they perform off-road.