I've noticed a few folks running different diameter tires and different brands from front to back on 4X4 machines. What makes these quads any different than a 4WD pickup where different diameter tires from front to back are a big no-no that's guaranteed to hose up the transfer case or some other driveline component in big hurry?
Different brands may not be much of an issue but I've noticed that sometimes brand X's 25" tire is 25.2" tall and brand Y's 25" is 25.6".
Remember, I'm relatively new to this quad business.

 

Wazzup Wolley!

Some old quads are geared different, front to rear, and require a different size tire. This is probably not what you want to know.

Most quads need to use the same size tire, front to back. It is just not as important to match the size as exactly as you need to on your truck. The ATV with worse matched tires willl consume more fuel in 4x4, and create more drivetrain wear. But, since there is no chain in the transfer case, and the contact psi per tire is low, and they are made a whole lot tougher for their size than a pickup truck, they can take a bit more of tire difference(especially on dirt) without any consequences. When I shop for a tire, I try to get one that has similar diamter. The mudrunner 26" is an example of a tire that is more mismatched for diameter than others (1/2" diff). Don't get overly concerned about the diameter, just do your best to keep it close when shopping for tires, and/or mixing different ones front to rear. This is quite a bit more important for full time 4x4s, since they would drag all the time and use more gas. Makes pretty much no difference on mud[img]i/expressions/face-icon-small-smile.gif[/img].


Two words of wisdom.

-A tire on a narrower rim will tend to be taller than the same one on a wider rim, but I have never seen more than 1/2" difference caused by different rim widths. I am sure you know that these ATV tires also change size more than a car tire when they have more air.

-The distance a tire rolls in one rev is not exactly PI*DIA, and can vary with inflation pressure, surface, rim width, etc. Different rolling distances make more drag. I noticed my 4x4 drag was greater with my stock tires. So, although I never measured the diameter or the rolling distance, I know the stock tires were less matched than the ones I have now. That 26" mudrunner has a full 3" difference in rolling distance, now thats a bit of a drag. The basck tires would ahve to push the fronts skidding along 3 inches per revolution. This 26" mudrunner situation is not too much for your quad to handle, it is just more noticeable drag than most. I realize you may not be looking at mudrunners, I just used it as an example.

 

I had a similar question about a month ago. I had Maxxis Sur Traks on the rear, 25x10x12. They were almost a full inch shorter than stock, so I decided to get the 26x12x12 Sur Traks and they are actually 26". With the 25's on the narrower front rims, they are now 25.5" tall with 6psi. The rears are 26" with 4psi in them. .5" difference isn't enough to do any damage in my opinion. Plus, the 26" Sur Traks are closer to stock than the 25's were in the back. Chris

 

Big bear chris, I know other quads come from the factory with worse diameter matches than you are running on. However, I would prefer to have it a bit closer, just to have less drag, and less 4x4 shifting difficulties.

A lot of other people have been thinkin about that maxxis 26" sur track, others are buying it and using it with a different make of tire.

As far as I can tell, the best choices for a 26" narrow front tire are:

-spider trac 26x9, kinda light (24lb), good handling on hard trails, lacks mud capabilities and might not have lateral bite on hardpack.

-Mudrunner 26x9, lightest (22 lb), fair on hard trails, good in mud, and has ok lateral bite.

-Bear Claw 26x9, heavy (26lb), best tread for hardpack, good lateral traction and ok in mud, better in snow.

I think every other tire is too heavy anyway. I am going to go with mudrunners in the front to match the Sur tracks. I can't find a better match.

 

So what I'm getting out of this is that a little difference is ok. Say 1/2" or less. Measuring my Prairie on stock rubber there is a 1/4" difference between from front to back. Measured from the ground to the center of the wheel hub. Doesn't sound like much but I've noticed that when shift from 4wd to 2wd when sitting still the front end of the quad jumps up about an inch when the front diff comes out of 4wd. This tells me that there is some driveline wind-up that can't possibaly be good for things.

 

I agree with you nyroc, I am pretty close in size. The next time I buy a tire it will be 26x9 tires for the front, probably one of the tires you mentioned above. I only went with the 25x10 up front is because the tires were only a year old. I moved the stock 25x10x12 Bumlops up front with the 25" Sur Traks in back. It drove pretty good, but I could tell a difference between the 8" and 10" wide tires up front. Thanks for the suggestions about tires, I'll probably be looking for new ones next year. Chris