285/70/17 on Stock Height
 

Greetings everyone.

I did a search and couldn't find anything definitive so I thought I'd put a quick post up and ask the question.

I have a 2018 Off Road Pro. Can I run a 285/70/17 tire on it or do I need to wait for a suspension lift? If I do need a suspension lift, would 2.5 inches be enough to clear the tires without doing anything else? Now, I know that tires vary greatly in actual size. The tires I would be running are in fact 32.7 inches which is what the 285/70/17's measurements are.

One more quick thing, can I run these tires on my stock wheels? Thanks!

Do it!!! Then take it to Target, crank the wheel at full lock out and jump curbs!!!

yes it works on stock height with the trail/trd off road wheels. youll need to remove the front mudflaps.

So the math is actually really easy to do. Let's take a look!

285/70R17 means the tread is 285mm wide (more on that in a second), the "aspect ratio" is 70 (the sidewall is 70% the tire width), and the wheel size is 17".

So we want to know how wide the tire actually is? That one is easy breezy. Just remember, 25.4 is your friend. Soooo... divide 285mm by 25.4 to get 11.22". Awesome, BUT not all tires are equal. The actual width will vary by tire manufacture, tire type, tire model, tire... you get the idea. There isn't any real standard around this, unfortunately.

So now we want to know how tall the tire is, and while slightly more complicated, it's still super easy. We'll do this in inches to make it easier. Ready?

Our aspect ratio is 70, which means we multiple our 11.22" by .7 to get the sidewall height. That equates to 7.85". Add that to your wheel size of 17" to get 24.85" and... hold on, something is wrong here. Oh! We forgot there are two sections of sidewall that contribute to the overall height. Add another 7.85" to the measurement, and viola! 32.7" is the height of your tire.

Remember, this is approximate because tires really do vary quite a decent amount. One tire might fit fine, another might rub. But hopefully this helped you understand it all a bit better.

In all honesty I wrote this in a fit of boredom, and I like this sort of thing anyway.

This graph is perfect thanks a bunch!

Attention starved are we?

Thanks a bunch.

Go talk to someone else like a 6th grader. If you had read my post, you would clearly see that I already had stated I was looking at buying a true 32.7 inch tire. The tire height was never a question as I had already looked into that and landed on a tire that was, again, a true 32.7. If that was too difficult for you to comprehend, then I can't help you there and suggest you go back to grade school. I may be new to the 4Runner modding world, but I am not new to turning wrenches. I've built heads/cam Vette's, Vipers, a 1000+HP Vette, and just sold my twin turbo Viper.

Go talk down to someone else.

I think the possibility to keep the mud flaps is there. Pushing max caster alignment at stock height plus molding the mud flaps / pulling them into the body mount with a zip tie should clear unless we’re adding wheel spacers. Then we only need a small reposition of the forward fender liner and maybe trim the lower fender lip.

you must have stayed at a Holiday Inn Express last night.

How many different iterations of “stock height” are there across all trim levels of 4Runner. Can’t possibly be the same for my Limited with X-REAS vs the TRD Pro on Fox shocks.


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After market upper control arms would make it much easier.

Doesn’t matter with IFS… Suspension geometry is fixed so when you hit a bump etc the wheel assembly swings up/down, inboard/outboard, etc through the rest of the arc. +/- nominal height from a TRD pro to x-reas to KDSS to non is within margins of errors and bump stops / steering limits aren’t changed.

Wasn't meant to be talking down to anyone. Maybe that info is helpful to someone else.

You seem super fun. Not to mention secure with yourself. Good luck, cap.

Ahhh… I actually understood that! Never thought of it that way until now.


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I think the main idea in his/her comment was that you were answering a question that no one asked. We basically all know the spec size of most common tire sizes. The OP wasn't really asking how physically large the tire's dimension are, but rather would they fit and clear in the spots that tend to rub/interfere. Test fitting tells us more than dimensions because fit is pretty close and nominal size as well as mfg spec size are not very accurate in many cases. So sometimes you just have to try it to see.

For example here's 3 sets of tires I have. All on OEM toyota wheels. The left most tires is a 285/70/17 Toyo AT2. Middle is a 285/75/17 Cooper AT3. Right is a 275/60/20 Cooper HTplus. The 275 nominally is the narrowest, but in real life it's the widest of the bunch. And the 285/75/17 Cooper is significantly narrower than the 285/70/17 Toyo. Height, width, wheel offset, and caster/alignment all effect whether the tires will rub at full steering lock.

http://www.toyota-4runner.org/attach...-1024x768-.jpg

The lift height is mostly irrelevant to tire fit. The only relevance is if it's a bracket lift or something that moves the control arms or if you have aftermarket caster correction UCAs. Caster correction UCAs make rub worse in most cases because it relocates the upper ball joint aft and moves the spindle closer to the firewall/body mount as compared to the stock UCA with the same LCA specs. It's a small amount because it moves the ball joint roughly 20-30mm aft to add 4* of caster and that translates to maybe 5-8mm of spindle location movement toward the body mount. So stock UCA with maxed out caster will fit the largest tire of any setup without body mount modifications or firewall relocation. But it'll drive poorly with stock UCA if you lift it much because you'll end up with low caster values and poor highway steering feel.

In my case the 285/70/17 and 275/60/20's cleared with only removal of the mud flaps and the fender liner adjustment/bumper cover trim. The 285/75/17 only fit with a BMC.

If you talked to someone in person the exact same way you just typed what you typed, then you would understand how disrespectful it is.

I'm plenty secure and fun, but I'm not going to put up with someone talking to me like I'm a 6th grader. You seem judgmental though. Maybe you should work on that and how you approach people online (we both know you wouldn't talk down to someone like this in person :) ). Have a good day.