Narrower Spare?

[phillyd2]

I'm considering moving up to Duratrac 285 Tires from 265. Based on what most of you have said the Duratrac 285 will fit the under truck spare location but I'm wondering how much lower, if any, it sticks down. Anybody have pictures of their 285 spare?

So, the question is - any issue with going with a narrower spare if the overall diameter remains the same?

 

[GrantK]

It will hang 20mm lower

 

[Jeremy556]

I'm considering moving up to Duratrac 285 Tires from 265. Based on what most of you have said the Duratrac 285 will fit the under truck spare location but I'm wondering how much lower, if any, it sticks down. Anybody have pictures of their 285 spare?

So, the question is - any issue with going with a narrower spare if the overall diameter remains the same?

Your diameter is going to change also, but with open diff it shouldn't be an issue. A 285/70/17 will be about 1 inch more diameter than 265/70/17

 

[phillyd2]

^ yeah I get that. I'm asking if I go bigger can I also buy a spare that is the same bigger diameter but not as wide.

 

[Okki]

^ yeah I get that. I'm asking if I go bigger can I also buy a spare that is the same bigger diameter but not as wide.

Based on the logic of the "donut" spare in sedans, I'm guessing you can, but you will want to restrict your top speed. handling will not be ideal, but with the same diameter you shouldn't have issues with the wheel sensors being off due to different wheel speeds.

I think diameter is the key measurement here; not width.

JMTC

Okki

 

[phillyd2]

^ exactly what I'm thinking but do know what I don't know and do like to hear what smarter guys think. Thanks.

 

[proquip]

You could go with a half worn 255/80/17 BFG KM2. That would be pretty close in diameter to the 285/70/17's DT and you actually shave about 10mm of overall depth so the tire tucks in underneath even better than the stock spare.

I've also considered getting a cheap 18" rim and putting on a 265/70/18. It'll be the same diameter as the 285/70/17 and the same width as the stock spare. Unfortunately, no one makes a 265/75/17.

Hope that helps.

 

[1engineer]

^ exactly what I'm thinking but do know what I don't know and do like to hear what smarter guys think. Thanks.

I know what you want to do and it will work no problem. The vehicle does not know or care what width you run. It does care however about what diameter you are using. I know you know this but for anyone else reading this thread pay attention: Contrary to what was posted above, DO NOT RUN mismatched tire diameters. Your ABS, VSC, A-TRAC. DAC and every other acronym on the truck assumes you have the same diameter of tire on all four corners. There is some percentage allowed for wear but not gross diameter difference.

 

[Okki]

I think diameter is the key measurement here; not width.
Okki

I know what you want to do and it will work no problem. The vehicle does not know or care what width you run. It does care however about what diameter you are using. I know you know this but for anyone else reading this thread pay attention: Contrary to what was posted above, DO NOT RUN mismatched tire diameters. Your ABS, VSC, A-TRAC. DAC and every other acronym on the truck assumes you have the same diameter of tire on all four corners. There is some percentage allowed for wear but not gross diameter difference.

Whoohooooo.. 1engineer said it better, but at least I had it right! :lol: :frisky: :guitar2:

Okki (ahhh it's the simple things in life that start the weekend off right)

 

[harper7]

The question is ....how much diameter makes a difference in the short amount of time you drive with the smaller spare to go get the flat fixed or replaced?

Because a 285/70/17 tire with a tread depth of 18/32,when the tread is worn down to the wear bars is about the same diameter or even smaller then a stock new 265/70/17 tire(spare) .

I figure Toyota had to have built in at least as much as the difference between a worn out tire's diameter and a new tire's diameter and the safety features still work(abs,trac,vsc, ect.).......which is about 2 tire sizes in diameter.

The main reason I upsized my spare to a 285/70/17 BFG AT is because I was worried if I was offroad or on icy,snowy road conditions out in the middle of nowhere and got a flat that the stock spare wouldn't cut it .
I wanted a spare that would be a close match to the others I was running for capability standards. In other words ,the spare Dunflop or whatever passenger tire spare wouldn't get me to where I could have my original fixed or replaced.Plan for the worst and hope for the best theory.

As proquip stated ,the best bet is a 255/80/17 ,which is about the biggest diameter you'll fit up under but not be too wide to be the low spot in the back. My 285/70/17 spare is the low spot(barely) in the middle in the back and has some drag marks to prove it. The rubber gives a little though as I run it low and drags on the hitch reciever the hardest.

 

[1engineer]

The question is ....how much diameter makes a difference in the short amount of time you drive with the smaller spare to go get the flat fixed or replaced?

Because a 285/70/17 tire with a tread depth of 18/32,when the tread is worn down to the wear bars is about the same diameter or even smaller then a stock new 265/70/17 tire(spare) .

I figure Toyota had to have built in at least as much as the difference between a worn out tire's diameter and a new tire's diameter and the safety features still work(abs,trac,vsc, ect.).......which is about 2 tire sizes in diameter.

The main reason I upsized my spare to a 285/70/17 BFG AT is because I was worried if I was offroad or on icy,snowy road conditions out in the middle of nowhere and got a flat that the stock spare wouldn't cut it .
I wanted a spare that would be a close match to the others I was running for capability standards. In other words ,the spare Dunflop or whatever passenger tire spare wouldn't get me to where I could have my original fixed or replaced.Plan for the worst and hope for the best theory.

As proquip stated ,the best bet is a 255/80/17 ,which is about the biggest diameter you'll fit up under but not be too wide to be the low spot in the back. My 285/70/17 spare is the low spot(barely) in the middle in the back and has some drag marks to prove it. The rubber gives a little though as I run it low and drags on the hitch reciever the hardest.

I agree. 285 worn vs. 265 new is basically same dia. How much did Toyota allow? I do not know. Best to stay same diameter all around though.

 

[phillyd2]

See, smarter guys do know more!

If one has one board air how about keeping a 285 spare at say 20 psi?

 

[Jeremy556]

See, smarter guys do know more!

If one has one board air how about keeping a 285 spare at say 20 psi?

Are you wanting it to take up less space? Won't work. With a tire just mounted on the bead and the valve core removed (ambient pressure), it is the same size and shape as when aired up if there is no load on it.

 

[Socalrugger]

I dont get most of what is listed above but I'm going to ask this anyway.... Can I fit a 285/50 20 underneath as my spare...? Thx guys

Edit- I've got a 2012 LE 4x4