Different size spare tyre (1 Viewer)

[brainhax]

Hi there

I was running 265*75*16 and now upgraded to 285*75*16.

MY spare tyre is still 265*75*16. Just want to know in the case of emergency, can I use the spare and drive out of the bush land at least ? A trip is due tomorrow. Too late to buy a spare 285*75*16

Thanks

 

[robnicko]

in case of emergency life preservation takes precedence over potential mechanical damage
that being said, get a 285 spare as soon as you can as being a constant 4wd is not a good idea to run a different size tyre to the other 3

 

[clx16]

If you have to use it. Keep your speeds down. Also if you have a viscous coupler in your transfer case still that will need you to drive even slower and Maybe take breaks to cool things down.

A good used tire/Tyre of the correct size can be a great option for a spare.

 

[BILT4ME]

Hi there

I was running 265*75*16 and now upgraded to 285*75*16.

MY spare tyre is still 265*75*16. Just want to know in the case of emergency, can I use the spare and drive out of the bush land at least ? A trip is due tomorrow. Too late to buy a spare 285*75*16

Thanks

If your truck has a K295 Limited Slip you will need to change a tire from a front axle to the rear, then place the spare on the front.

If there is a locker fully engaged or a limited slip, that axle must have the same size tire on both ends.

Otherwise, stay under 25 MPH (40 KPH) so you don't generate heat inside the differential.

If the spare is on the front and you have 2WD option and can unlock the front hubs, unlock them while on the road. You can lock them back in when "digging or in slick areas", as the tire difference won't hurt the differential.


I know from personal experience that 100 MPH for 14 miles with tires that are 3" diameter difference will result in a LOT of heat, a fire in the differential, and a sheared pinion.

 

[bicycleagent003]

You can easily get a cheap used spare on Craigslist of FB marketplace. Or even a tire shop. I did that once and had it mounted up. Very cheap option, it's a no brainer.

 

[145236]

From my perhaps faulty knowledge of tires, in sizing the 285 is tread width, the next number (75) is aspect ratio, and third the wheel diameter. So, your running tires and your spare should be about the same diameter. Differentials and viscous couplers care about tire circumference, not tread width. Get a cloth tape measure and compare circumference of the spare to the others. Any thing else is guesswork and speculation.

 

[BILT4ME]

From my perhaps faulty knowledge of tires, in sizing the 285 is tread width, the next number (75) is aspect ratio, and third the wheel diameter. So, your running tires and your spare should be about the same diameter. Differentials and viscous couplers care about tire circumference, not tread width. Get a cloth tape measure and compare circumference of the spare to the others. Any thing else is guesswork and speculation.

In this case, a 285/75-16 is about 33" diameter.
A 265/75-16 is about 31" diameter.

It is a significant difference in diameter, but if kept SLOW then it will be ok for emergency purposes only.

 

[BILT4ME]

You can easily get a cheap used spare on Craigslist of FB marketplace. Or even a tire shop. I did that once and had it mounted up. Very cheap option, it's a no brainer.

Probably not so much in Australia.....

 

[Broski]

Hi there

I was running 265*75*16 and now upgraded to 285*75*16.

MY spare tyre is still 265*75*16. Just want to know in the case of emergency, can I use the spare and drive out of the bush land at least ? A trip is due tomorrow. Too late to buy a spare 285*75*16

Thanks

Go on the trip and don’t worry about it.
I don’t think it’s a big deal at all.

 

[mudgudgeon]

Hi there

I was running 265*75*16 and now upgraded to 285*75*16.

MY spare tyre is still 265*75*16. Just want to know in the case of emergency, can I use the spare and drive out of the bush land at least ? A trip is due tomorrow. Too late to buy a spare 285*75*16

Thanks

Yes.

Carried an odd sized spare for years, and have no issue with limping home on one.


Many production cars come with a space saver spare that is significantly smaller than the road tires.

 

[mudgudgeon]

Probably not so much in Australia.....

FB, Gumtree, eBay, local tire shop . . .

 

[scottryana]

In Aus are the trucks Full-time AWD or are the Part time? In a part time 4wd truck you wouldn't have any issues. If Full-time then it has been covered above.

 

[mudgudgeon]

In Aus are the trucks Full-time AWD or are the Part time? In a part time 4wd truck you wouldn't have any issues. If Full-time then it has been covered above.

Both

 

[Kernal]

Kinda obvious but FWIW, bring a small air compressor and tire patch kit on the trip if no time to get the correct size spare??

 

[josephpampliega]

Put a 255 85 16 as a spare which is also equivalent to 33". Will add 30mm more clearance off the ground than the 285 75 16.

 

[bdog75]

My recommendation would be, put he mismatched tires on the front , remove the front driveline, Lock the center differential (center diff lock switch required).
I tried to limp home once, it didn't take long before before the front diff oil got hot and started puking out the breather. Years later while digging around in the transfer case I found the viscous coupler was split open with wire spinning around eating the the walls of the transfer case. Note: I've done a lot of wheeling in the past in low range with the center diff unlocked, I never do this anymore.