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Tyres/diffs

I need some new tyres for my 2000 Cherokee. Currently it has Goodyear Wranglers and I want to keep the same. The front have worn much quicker than the rears. The fronts have about 1/8" of tread, compared to about 1/4" on the rears.

So off I go to price some new ones (just two, I figure the rears will last another year) at Sears, and they tell me they will not fit just two, unless the non-replaced ones are within a very small tread depth of the new ones. Can't remember the measurement, but remember thinking it was small. So small that the non-replaced tyres would probably have to be not many miles off brand new themselves. The reason they gave was that it might damage the differentials (although the kid working there didn;t seem too sure that this was the reason).

So my question is, would it really cause any damage having front and rear tyres with different tread depths. I would have thought it was so marginal as to make no difference. Presumably it could only be an issue in 4wd, but with winter closing in fast here in Minnesota....

And for the bonus prize, if the difference of tread depths matters that much, am I doing damage driving round with the 1/8" difference I currently have?!

TIA

Mat

Reply to
Mat and Suzy
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That small a difference won't harm the 4x4 system. Running "tyres" of different sizes front & rear is a no-no.

(When did they start spelling tire "tyre in Minnesota?)

Reply to
Gerald G. McGeorge

If you have locking diffs, then it could be a concern... only from side-to-side. Your transfer case is the issue when you are talking front-to-rear difference.

They want to sell you four tires (tyres?) and make money off your perfectly good discarded tires, which they will charge you to "get rid of". You need two new tires on the front, that is all. You really should rotate your tires... read your owner's manual sometime, specifically pages 120-125. What other maintenance are you neglecting?

You should never use 4wd unless the road conditions are slippery enough that tire size wouldn't matter, anyway... unless you have Select-Trac, which you did not mention. I'm assuming that you have Command-Trac... check your sun visor to be sure. If you have Select-Trac, then your front and rear diffs are allowed to spin at different rates anyway when in full-time 4wd.

None... but you're not in 4wd. The concern comes into play when

4wd is engaged in part-time mode. __ Steve .
Reply to
Stephen Cowell

Reply to
RichH

The four cylinder Wranglers and Cherokees come stock with 4.11 gears on the back and 4.10 on the front. This is similar in effect to having 1/8" different tread depth. Command Trac 4wd is only intended to be used off road anyway. Off road there is less strain on drive line components because of slippage, which is why you put the vehicle into 4wd in the first place.

Earle

Reply to
Earle Horton

The tire shop is correct as far as they are concerned.

If you use 4x4 in 'part time' mode you can damage drive train parts or blow u-joints if the front and rear tires are not the same or almost the same size.

Even driving on dirt can cause damage or at least stress the crap out of it depending on the dirt. I have come out of dirt after a run in 4x4 and no way could I get it out of 4x4 while still moving forward. I had enough traction still, that it was wound up tight with matching tires, let alone if they were mis matched. I had to put it in reverse and spin the tires to loosen it up so it would shift.

If you drive on snow with odd sized tires, sure they will slip and scuff easy. Ever try to turn a corner in the snow with the front tires not wanting to roll like you had the brakes on? You get the idea, it won't turn for shit. Even at the best of times in slush, the scuff can catch you by surprise when the thing wants to just go straight. In the city, I drop it to 2 wheel drive to go left at an intersection if the intersections are slush, then back to 4 high once I am straightened back out.

My $0.02,

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Mat and Suzy wrote:

Reply to
Mike Romain

....when they got here via the UK. good spot though!

Reply to
Mat and Suzy

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