Different sized tires in front for a short trip (1 Viewer)

[dpr64]

Hi...Picking up my FZJ80 and the 2 front tires are shot... I have to drive it back about 500 miles and have access to 2 tires/wheels to put on the front except that they are 265x70x16 instead of the 275x70x16 tires that are on there. Being the AWD setup, etc., will I have a problem driving that with different sized tires in front vs the back? I believe the size difference is very small...
Thanks..

 

[mikedamageinc]

Only if you pull the front driveshaft and lock the center diff, otherwise you will destroy the transfer case.

I wouldn't even drive the same tires with too much uneven wear.

 

[Ballsie]

Does it have a spare? You will only need 1 more 265/70 if there is a spare you can throw on. You don't want to damage the xfer case on your new truck. its a total of 8 nuts/bolts to pull the front drive shaft. gotta lock the center diff though. You can temporarily re-purpose the hazard switch to lock the diff.

 

[arcteryx]

why not just bring 2 tires with you and put them on?

 

[bmac1996acc]

You'll be fine.

 

[iwashmycar]

x2. I see no problem with different sizes front and rear.

 

[jonheld]

Only if you pull the front driveshaft and lock the center diff, otherwise you will destroy the transfer case.

I wouldn't even drive the same tires with too much uneven wear.

Yes, because the transfer case is made from eggshells and dove feathers. That's why you should never go around corners.

 

[iwashmycar]

lol true... driving a trip with more curves in one direction will have tires turning in much greater differences than any uneven wear

 

[Booger weldz]

I had about 2500 miles on mismatched tires. 36/37 iroks. They measured 35.25 and 35.75 or so.

 

[mikedamageinc]

Yes, because the transfer case is made from eggshells and dove feathers. That's why you should never go around corners.

Yep do what you want, just my opinion. I don't have an owners manual for the TLC but other awd vehicles have strict warnings against mismatched sizes. And uneven wear I was talking about two old and two new tires not just normal wear.

 

[dpr64]

Wish I could bring some tires with me but I am flying in and have to drive the beast home.... Right front is especially bad and the spare is not the same size. Some guy in the area has a set of 4 on rims for $150 so I might just do that or pick up a single one and have it mounted at discount tire.

 

[fj80pb]

In effect, the difference in diameter between these tires sizes is less than 2%.
Not to pile on, but last time I checked the engineering purpose of a diff is to allow different speed rotations between ends. The center diff, for as long isn't locked, does that all the time and will therefore allow different speed rotation at each end. It shouldn't be big deal for a short trip.
Cheers

 

[jonheld]

Rotational difference between new and old tires of the same make and size is irrelevant.

 

[BILT4ME]

Put one bad one on the front and one bad one on the rear. It will average your drive shaft speeds to save your transfer case. However, now your open differentials will be turning a lot more.

I would do it for 10 miles under 35 MPH. I would NOT do it for 500 miles of highway travel. If they are just uneven wear of the same make/size of tire, it will most likely not be an issue. Take a tape measure an measure from the ground to the center of the hub on all 4 wheels (Rolling Radius). If that dimension (assuming all tire pressures are correct) is within 1/16", you should be just fine.

Note: Assuming a 33" diameter tire, it will travel 611.15 revolutions/mile. A 33-1/4" diameter tire will travel 606.56 revolutions/mile, a difference of 4.58 revolutions per mile. On a trip of 500 miles, the back end will get there 3.77 miles AHEAD of the front end! Now THAT's progress!

 

[hammerheadfistpunch]

Its not a good idea, since the FZJ has a viscous coupler and that much high speed driving migh break down the fluid, but at this point it might already be toast. I personally would lock the CDL and remove the driveshaft, its actually not that much work.

 

[hammerheadfistpunch]

In effect, the difference in diameter between these tires sizes is less than 2%.
Not to pile on, but last time I checked the engineering purpose of a diff is to allow different speed rotations between ends. The center diff, for as long isn't locked, does that all the time and will therefore allow different speed rotation at each end. It shouldn't be big deal for a short trip.
Cheers

The center diff doesn't care, but viscous coupler might. the purpose of a viscous coupler is to reach homeostasis between the front and rear axle speeds, making it work at different speeds over a long time is NOT what it was designed to do.

 

[BVCOTaco]

IIRC the 265 and 275 are the width of the tire. The 70 is the ratio of the tire sidewall which multiplied by 2 and then adding in the diameter of the tim would give you the height.
Therefore the 2 tire sizes are the same. The only difference being would be the width of the tire therefore making no difference in turning speeds of the different sized tires.
Read up here on tire sizes...
http://www.tacomaworld.com/forum/wheels-tires/23715-how-understand-metric-tire-sizes.html

 

[hammerheadfistpunch]

IIRC the 265 and 275 are the width of the tire. The 70 is the ratio of the tire sidewall which multiplied by 2 and then adding in the diameter of the tim would give you the height.
Therefore the 2 tire sizes are the same. The only difference being would be the width of the tire therefore making no difference in turning speeds of the different sized tires.
Read up here on tire sizes...
http://www.tacomaworld.com/forum/wheels-tires/23715-how-understand-metric-tire-sizes.html

I saw 275 and assumed it was going to be 75 not 70. in which case, I agree...totally go for it.

 

[jonheld]

You know, I hate to interject facts into this thread, but the rotational difference between those 2 tire sizes equates to 11.65 revolutions per mile. Now this might not be the best thing as far as handling and safety goes, but mechanically you can drive across country without issue.

 

[BVCOTaco]

How can they have different revolutions per mile when they are the EXACT same diameter and only a different width?