CILO

Hi All,

Ive got a dilema. the other day my bro in law tells me that he's been told by a 3 different tire places that you have to have the same brand tire on all 4 wheels of a 4x4 in order to avoid damaging the transmission. Personally, I think that's a load of caca made up by tire dealers. So in the pursuit of busting this myth I searched online looking for anything to prove this wrong. That is when I came across this article:

http://www.tirerack.com/tires/tirete....jsp?techid=18

so now I'm thinking there is some truth to this....some. However, I dont think it would apply to all 4x4 vehicles. I think this would relate primarily to vehicles with all-wheel drive and weaker drivetrains that are not designed for off-road driving (Crossover vehicles) . Also, I think mismatching 2 rear tires (as in our case) would not cause a damaging strain to our drivetrains because the open differentials would allow for any differences in diameter. So as I ponder this I thought it would be a good Idea to ask for an unbiased opinion on this matter.

So.... what's your opinions on this????????????

91_4x4runner

My friend (1976 Chevy Blazer) was running 2 different tire treads without problem.

My 91 4Runner, when I got it, had 3 different types of tires on it. Besides serious wobbling at high speed, I had no problems.

Theres a picture somewhere in the wheeling section of a toyota truck running 35+ boggers in the rear and then smaller tires in the front while wheeling.

Alot of the farming 2WD trucks here in Texas run mud terrains or aggressive all terrains in back, and something lighter in front....

My conclusion is that it is possible without damaging anything........ Other than what I've seen... I have no idea. You do need to keep the size the same though, or you will run into a big gearing issue.

If you run larger tires in back, you need your gear ratio to match to smaller tires in front or you could tear up your drivetrain.

Corey

iTrader: (1)

You should use the same brand and size, as size varries between makers of tires, even in the same size.

All tires must be of the same size when in 4WD or you can get, crap, brain fart, can not rememeber the name.
Thats what happens when you get old
I wanna say bondage, but somehow that name does not sound right
I believe the name I am looking for starts with a "b", it is on the tip of my tounge, er fingertips, but I can not coax it out right now.

But yes, use the same make to be safe.

Pozi

IMHO running different brand tires front and rear is not necessarily a bad thing if they are of the same diameter. However running different size tires front and rear is bad (as stated in the link you provided). But with that said I have run different size tires (32" vs. 33")on my FJ40 on numerous occasions (poor high school student) without any apparent repercussions; but I always run 2wd on the pavement switching to 4wd once I hit the trail (my thinking was that the tire slippage from the loose dirt allowed the "cushion" for the difference in tire size.

4Rocker

Im not an expert on the subject, but I think that the different size tires would only be a problem on newer e vehicles with all-wheel drive. Vehicles with a part time 4WD system (my 4runner at least) lock the front and rear wheels by a manual control by the driver. SOME AWD systems use speed sensors on each wheel to determine when a wheel is moving faster (slipping) and then engage the awd as necessary. If different size tires are used on a vehicle with this type of AWD, it is possible that the computers will register a great enough difference in wheel rpms and think it is slipping, thus engaging the awd at times when it may not be wanted (for example, at highway speeds). On a 1st-3rd Gen 4Runner or 1st gen tacoma or earlier truck, you should be ok as long as tires are close in size.

04 Rocko Taco

While Corey is right, different brands will be slightly different diameters in the same size tire. I dont think its entirely neccesary to run the same brand, you will be better off...but not neccesary, but they do have to be the same SIZE!! left to right. Front to rear, seems when in 4WD would need to be the same, if its 2WD front tires dont matter compared to the back tires. but left to right they need to be the SAME!

Greg_Canada

Size matters when you have high traction, it will cause BINDING (not bondage LMAO) of the driveline.
But if you're out on a slippery trail it wont matter, because 'them tires will be spinning anyways.
You can mismatch front and back, but not side to side.
But if you have 2 different sized tires, dont EVER put it in 4wd on the road.

Corey

iTrader: (1)

Binding actualy came to me a few minutes ago as I was working
Does sound a tad better than bondage.
Well now, I guess that depends

kwikrnu

If you have an open diff why can't you run different size tires side to side?

Intrepid

You can run different tires all around, it won't really be a big deal unless you are always locked in the back, like a spooland even then, it would just cause one tire to chirp a bit as the "bondage" becomes too much, haha. As long as they are basically the same size you will be fine. In the same way that you can fun 4.86's in one diff and 4.88's in another (I know it doesn't apply to our trucks specifically, it can apply to some) because they are close enough to not matter, you can run a 31.5" tire with a 31" tire and you will never notice a difference. Right now that is the situation on the front of my tacoma. I blew a sidewall on one of my Mickey Thompsons and I had a spare BFG AT hanging around so I threw it on, it is slightly larger, but I have never had any problems with it.

rockota

First question - Why would anyone WANT to run more than one brand/size? What's the requirement?

Second - NO two brands product the same size tire, regardless of the label. They are always off by a tad. Is it a big deal? After all, varying tire pressure on the same brand can do the same thing, right? While true, it at least gives you the opportunity to control that aspect.

Third - there is a lot of gray area here that must be considered.

4Rocker has some good points about computer control ABS/traction control systems on newer vehicles - they'll likely not enjoy the different size tires.

However, I disagree with the assessment that ALL AWD vehicles will struggle with different brand/size tires. In fact, I believe that ONLY AWD vehicles w/ open front and rear diffs AND open diff in the tcase can actually handle the different brand/size tire w/o a problem. Add any sort of limited slip to this and you will have problems; everything from extreme binding to simple premature wear.

For a part time rig w/ no center diff, running different sizes/brands is bad juju, IMHO. If you must do it, make sure they are the same side to side and then disconnect the front shaft to ask as cheap insurance. If you want to use 4wd, make sure you only do it on surfaces that will reduce traction enough to make up for the differences w/o "bondage".

Just my opinion.

Greg_Canada

You can it's just that it's not good to do it, as it effects the handling and stability of the vehicle. That's why you're not supposed to leave a spare on that long....