Login Register Sign up for the GRM e-newsletter

Login to post Forums » Grassroots Motorsports » Different sized tires front/rear on 4WD?
  • Jamesc2123

    Oct. 25, 2011 4:10 p.m. Jamesc2123 Reader

    I need a pair of snow tires to go with the two I already have for a Suzuki Sidekick. I found a good pair for cheap on CL, but they are a slightly different size. Stock tire size is 215/65/16, while the pair i found online are 225/60/16.

    The difference in overall diameter is 4/10 inch. Question is, can I run the Sidekick in 4wd with different size tires on each axle? Or, will it damage something like the transfer case if different tires are trying to spin it at different speeds?

  • ransom

    Oct. 25, 2011 4:24 p.m. ransom Dork

    Let's say these tires are roughly 24" in diameter. 0.4" is then about 1.7%.

    At 30 mph, there will be about a 0.5mph difference between the axles. I would think your transfer case (and tires and diffs) would dislike that rather a lot on a continuous basis.

    If you never engaged 4wd when you weren't on snow, I don't know how strangely it would behave.

  • iceracer

    Oct. 25, 2011 5:50 p.m. iceracer SuperDork

    If you only use 4wd when it is snowy, icey or offroad, you probably won't have a problem. Now on pavement, that is a whole different story. On another post, I told about the guy with an old Jeep. He put two ne tires on the rear, he complained of a loss of power when he used 4wd. His front tires were bald. One way to get around the problem is to put the same size tire on each side. The axles differential will take care of the difference.

  • petemc53555

    Nov. 10, 2011 2:14 p.m. petemc53555 New Reader

    What about different sizes on front of a FWD car w/o LSD? 185/65/14 vs 195/60/14 (~1/4" diameter or 7% different)

  • ransom

    Nov. 10, 2011 2:23 p.m. ransom Dork

    Good question.

    I'd tend to think that the diff wouldn't care too much, but I certainly wouldn't want to drive it like that more than to get home: I expect the 7% smaller side will get equivalently more torque at the contact patch, for both accel and braking.

  • petemc53555

    Nov. 10, 2011 2:41 p.m. petemc53555 New Reader

    I'm gonna find out!

  • irish44j

    Nov. 10, 2011 4:18 p.m. irish44j Dork

    well, at least you'll have the hundred bucks you saved to pay to replace your transfer case......

    new snow tires are pretty cheap.....I don't see any reason to risk messing up your drivetrain just to save a hundred bucks.

  • Nov. 10, 2011 5:15 p.m. bigbens6 Reader

    Don't do it, or if you have too do the math and have the new tires shaved to an appropriate tread depth that your roll out is identical.... differentials are alot more $ than buying proper tires in the first place...

  • iceracer

    Nov. 10, 2011 5:22 p.m. iceracer SuperDork

    Main thing, even stock, it is reccomended to NOT drive on dry pavement in 4WD. Unless of course you have a center differential.

  • ransom

    Nov. 10, 2011 5:24 p.m. ransom Dork

    petemc53555 wrote:

    What about different sizes on front of a FWD car w/o LSD? 185/65/14 vs 195/60/14 (~1/4" diameter or 7% different)

    It dawns on me... 1/4" is a lot less than 7% of a tire's height. 1/4" is about 7% of 3.5"...

  • ransom

    Nov. 10, 2011 5:26 p.m. ransom Dork

    irish44j wrote:

    well, at least you'll have the hundred bucks you saved to pay to replace your transfer case......

    new snow tires are pretty cheap.....I don't see any reason to risk messing up your drivetrain just to save a hundred bucks.

    Assuming this is in reply to petemc53555, he's talking front wheel drive; no transfer case.

    I still think it sounds like a bad idea from a safety/driveability standpoint. But I don't think it should cause more than a bit more than usual wear on the spider gears...

  • mith612

    Nov. 10, 2011 6:32 p.m. mith612 Reader

    Jamesc2123 wrote:

    I need a pair of snow tires to go with the two I already have for a Suzuki Sidekick. I found a good pair for cheap on CL

    Why not try to find a good set of four snow on CL and flip the two good ones you have? If all four are the same size (don't necessarily have to be stock size though) all will be good.

 
Tire Rack- Revolutionizing Tire Buying

You'll need to log in to post.