How many of you upsize your spare when upsizing your tires?

When I upgraded to 33s from 32s I didn't get a spare because I was being cheap and figured I'd save for a bit and get the full size spare a little later.

Went on an offroad trip for 3 days and what happens the first day out on a remote trail? Blew a sidewall on one of the brand new tires.

Had to run my 32" spare since it was all I had. I switched up the tires so that the rears matched (most important since those are always spinning) and put the mismatched one up front. Finished the weekend trip that way and had to drive 300 miles home since it was a holiday weekend and no shops were open on the drive back.

Offroad in 4wd on low traction surface you'd be fine with slightly mismatched fronts, but driving on the street you do not want your primary drive wheels (the rears) to be mismatched...that will F up your rear diff in short order.

Bite the bullet and get a full size spare when you upgrade, not worth the risk or headache running without one.

 

That’s simply not true. The middle number is the aspect ratio, not a fixed value. A 245/75 has a width of 245mm and a sidewall ratio of .75, meaning the sidewall is 184mm tall. A 265/75 has a sidewalk that is 199mm tall. A 285/75 has a side wall that is 214mm tall.

 

Sounds like you need to take your own advice and look at some tyre charts, to understand how the sizing works.

 

That's not how that works man. The middle number is a percentage of the tire width. A 200/50 tire is 200mm wide, 100mm tall on either side of the rim. Moving to a 400/50 at the same size rim would be 400mm wide, and 200mm on either side of the rim. That can be a big difference at the same aspect ratio. Obviously those are examples and not real available sizes.

 

Also

A 200/55 is absolutely taller than a 190/55 with the same rim.

 

Agree. If you stick with 33s, you update your spare to a 33 once and keep it through all your sets of 33s. Doesn't have to be matching tread, I just want a legitimately capable 33 to match.

 

You missed the part where I said "unless you spend a lot of time in 4WD". If you're wheeling in remote areas then you should probably get a matching spare, but if your truck spends most of its time on pavement then it's not necessary.

 

No I didn’t miss that part. You missed my point. If you are off road at all, you will be sorry for skimping on your spare. Even if I only spent 10% of my time off road I would still do it because that’s when it will really count...

 

I've gotten a matching spare....had a whole discussion about it here

https://www.tacomaworld.com/threads/mismatched-spare-issues.598742/

 

I took the 15” spare out of a civic. So much more room under the truck for activities now!!


Seriously... same diameter spare or why even carry it.

Only exception is if you’re solely a pavement princess that doesn’t do anything but drive in areas with cell service and plan to call a tow truck every time you get a flat. Of course that’s only in a perfect world with a perfect situation. Which brings us back to same diameter damn it!

 

If money was no object and you still live with mom and dad, then sure... match them all up. However, if you pay taxes and live in California (not on the street), then the original spare will get you home or to the tire shop!

 

Hey dude, I used to race bikes, same tire measurements a 190 is not at wide as a 200 neither is a 180 vs a 200.

The middle number is how tall the tire is

Or do you still think a 40 series tyre is the same height as a 60?

There is always a slight variation a 35 is not exactly a 35

But that’s fine, been doing this longer than I care to say, I will see my self out. No need to diminish my brain power.

 

No it ain’t a 200/55-17 is wider not taller,
A 240/55-17 is even wider
A 200/50-17 is lower in profile lower profile is a lower tyre. Or is maths wrong?

Been racing too long to get it wrong.

 

a 200/55/17 is wider AND taller than a 190/55/17......that 55 is the sidewall ratio, meaning as you go wider you also go taller if you have the same ratio

took me a while to get it straight......@Pilsner got it right

 

I'm not crapping on anyone, but if you change tire size, it's not a luxury to to buy the full set. It's required. You can totally take the cheap road, like I did. I switched to 265/70/17s, and I kept my 16" steel spare rim. I put a 265/75/16 on it, and it's even a different brand (K02 on the truck, Falken Wildpeak as a spare). Saved a good $300ish bucks. Because it's a spare I might never use... But it's at least the right size so I don't need to sweat it if things go wrong.

In California. And I don't live in mom's basement

Ultimately, it all comes down to your tolerance for risk. I'm on the cautious side...

 

If you can’t afford a full size spare you might have to rethink your budget!

 

To bad, cause it ain’t true a 190 5017 should be the same as a 180 55 in terms of handling and height. It ain’t the 190 55 is a taller tyre than the 190 50 which also correlates to the front tyre on a bike going from a 120 60 to a 120 65

The pic you have shows the total height which is nothing .5 is not even a real change tyre pressure negates that little bit

Especially if the rim is the same size, it curls the tyre and flattens it out.

A 35 12.50 does not become a 36 just by wheel size. Nor does it become a 36 simply by going to a 13 or 14 wide unless the tyre is put on a dinky width wheel.

I’m done no here is ever gonna see the full picture so...exit, stage right.

 

I got bad news for you. If you cant afford a spare tire to match the size of the other four then you may soon find yourself in your mom’s basement regardless.

 

Unless you’re not originally from the U.S. or Canada... this alone makes you suspect!

 

Damn, you beat me to it...