Is it ok for spare tire to be 1" smaller in diameter?

Open diffs mean it doesn't matter - it's not a Subaru (or awd with slipping clutches)..

 

Yes. You would just want to stay out of 4wd on hard packed surfaces. Basically, it will end your wheeling day, but will get you back home.

 

Its not good for the diffs to be constantly making up that difference in speed when going straight instead of just in corners.

 

It will be alright to get you home or to the tire shop until you get a tire replaced/repaired.
I know the shuffle, our forester spare goes on the back and fuse gets pulled under the hood.. it's an added pain in the butt.
265/65 to 265/70 is not going to explode a diff.

 

Luckily a good friend of mine has a lift I have access to. But I’ve done it with a floor jack.

 

I do the 5 tire, rearward cross. https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=43

 

Other than the 5 tire rotation guys or when you upsized, when when was the last time anyone replaced their spare? I always put the spare on the rear for the short (50 miles or less) drive to get it fixed. Especially if I'm helping someone I don't know. The spare is normally smaller or old/ in crappy shape. If it blows out the vehicle will be more controllable if that happened on the rear.


For my spare I normally take the best tire of the 4 I'm running at the time of replacement and have that mounted as the spare. I also carry a plug kit and oba.

 

True, but then you're dependent on the assumption that you'll be able to get to a tire shop in a short distance. The first and only time I've needed a spare it was 10pm on a Friday night and I was in the middle of Kansas. I had a decent spare and that let me finish my trip without worry and deal with it at my leisure, which turned out to be a couple of days later. 100% worth having the right size tire IMO.

 

Any idea whether this works with TPMS?

 

Hmm, so when I switch from 255/70R17 winters to 265/70R17 Summers I'll need another spare, blizzaks are $241ea, and then a wheel is going to be $90, plus $289ea for another ToyoRT as my summer spare.. So you figure spending $620 plus mount+bal is better off than maybe having to put a 1"or 1/2" diam difference wheel on an open diff in an emergency?

I've daily driven a Tacoma for 10 years now, and went 12 years before that with a 86 pickup.. needed the spare zero times.
I'll just keep my OEM spare IMO.

 

So, you're saying people have different situations and the same thing doesn't work for everyone?

 

I've always done five tire rotations on a Jeep with matching wheels and tires, that way I use the spare, always have a matching spare, and it's got equal wear. I'd like to do the same with my Tacoma but I'd have to get a matching wheel, and of course the issue with the TPMS. Another nice thing is just makes rotating ires easy ... raise up a wheel, replace, move to the next!

 

Calling @eurowner for his 3rd gen TPMS knowledge…

 

Specific Tpms sensor would have to be reprogrammed every time

 

Alright, this thread seems to say you can't add a 5th TPMS sensor to the ECU: https://www.tacomaworld.com/threads/is-it-possible-to-add-a-5th-tpms-sensor.426434/

However, this video seems to have the practical answer: https://www.youtube.com/watch?v=kkJJabCQaqA

The TPMS sensors turn on based on centrifugal force or changing the air pressure. The receiver to pick up all 4 drive wheels is mounted in the rear passenger side a-pillar. Based on what the guy is saying, yes, you can install 5 TPMS sensors. The catch is that you have to program your truck to the active TPMS sensors.

So, that would mean you'd have to:
-label each tire and know the TPMS serial numbers
-Rotate your tires
-Drive a bit to make sure all 4 drive tires are activated and the 5th tire shuts itself off
-use Techstream to reprogram your ecu to pick up the 4 active sensors

 

If i had a full lift in my garage where it would make dropping the spare and rotations seamless, yes I would be the type of person to rotate my spare into rotation. But no, i dont, and no i never touch my spare except once a year when i check the tire pressure and fluid filim the area

 

It's not hard to do 5 wheel rotations with just a jack (and your level of safety - I also support that corner with a jackstand). I never have more than one wheel off the truck at one time.

Now a 4 wheel rotation - that's when you have at least 2 wheels off the vehicle.

 

For those using a 4 tire rotation

If you have a matching full size spare with 17mm tread depth, and after 50k miles your other four tires have 4mm tread depth left, the spare is 1 inch larger. (13mm on the top of the tire + 13mm on the bottom = 1 inch) So it's equally good for the spare to be 1 inch smaller because after 50k miles it will actually be the same size.

 

What tires are you running with 17mm of tread depth? 8-9mm is avg for new tires.