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Discussion Starter #1
Hey -
been posting a couple existing threads, but thought I would not hijack anyone's thread and just make my own.

I'm looking to put wider tires on my 18" limited wheels. stock is 235/55/R18.
Has anyone gone wider? Anyone gone to 255mm width? Any scrubbing issues?
I would guess not, but just wanted to check.

Been considering:

* BF G's - All Terrain T/A KO2 - 255mm width
* General Grabber AT2 - 255mm width
* Nitto Long Trail - 255mm width
* Nitto TerraGrappler G2 - 255mm width

Any help or previous experience on the matter is appreciated!

Thank you
 

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Hello - anyone have any luck? I'm starting to think 255mm wide may be too much w/o spacers. I put the wheel at full lock this weekend and it looks like there is barely enough room for the stock 235's to clear - I think scrubbing could be an issue at full lock...
 

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Hey -
been posting a couple existing threads, but thought I would not hijack anyone's thread and just make my own.

I'm looking to put wider tires on my 18" limited wheels. stock is 235/55/R18.
Has anyone gone wider? Anyone gone to 255mm width? Any scrubbing issues?
I would guess not, but just wanted to check.

Been considering:

* BF G's - All Terrain T/A KO2 - 255mm width
* General Grabber AT2 - 255mm width
* Nitto Long Trail - 255mm width
* Nitto TerraGrappler G2 - 255mm width

Any help or previous experience on the matter is appreciated!

Thank you
OK. Here's a deal. The width of original 235/55/18 of the most tires vary from 9,6 to 9.7 inches. The width of 255/55/18 usually 10.4 which makes 0.8 inch difference. Dividing by 2 we'll get 0.4 inch extra of tire to deal with. I don't think this could be an issue, but you also have to consider the following:
1) You tire will be heavier.
2) With the wider tire's contact surface your gas consumption will go up.
3) The overall diameter of course will also be bigger, which will lead to inaccurate speedometer readings. Overall diameter of 235/55/18 is 28.1 or 28.2 inch depending on tire's brand and 255/55/18 is from 29 to 29.1
Here's a link to calculate the speedometer readings of different tire sizes at different speed:

https://www.tacomaworld.com/tirecalc

In order to stay with the same (original) overall diameter you have to go for 255/50/18 which is 28 to 28.1. In this case your speedometer reading will be more or less accurate.
4) It also depends on your wheels offset. The lower (30 - 35) offset can easily compensate that 0.4 inch of extra tire inside the space.
Good luck.
P.S. I'm also a big fan of wider tires.
 

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I have played with tire sizes on bikes, cars , and trucks for years.

I use this calculation tool from a Miata forum to figure out the differences in tires: Tire size calculator

Unless you are going to go in and change the computer to adjust for the different wheel speeds you are really going to want to keep the circumference / diameter pretty close to OEM

The other thing people don't take into consideration especially when changing wheels and tires to a completely different size, even with a computer flash to adjust the speedo, is that if you get a flat and put on the smaller spare tire with the bigger wheels it is going to create havoc with the ABS and traction control.

Ever have a kid come in to your shop crying that the Posi / limited slip in his car or truck is fried because he had mismatched tires on the car for 50 miles? I have!

The other issue you have is each tire has an optimum rim size range. Just because you can shoe horn the tire on the wheel doesn't mean you are not pinching the sidewalls in to the point the outside of the tires are not making contact with the ground. Sure you can deflate them a bit to cheat, but then watch the TPMS go nuts.

On my F150, that has 7 lug wheels, ( the only vehicle on the planet that uses 7 lug wheels are the heavy duty plow prep f150's) I had Centerline machine me aluminum wheels using blanks that had a close offset, but I could only get them in 8" width. In order to keep the ABS, Speedo, and spare tire equation balanced so the tire was the same circumference I used that tire calculator and went up a little on the width, and down on the aspect ratio, and I am within 2% of the stock tire size, everything works, and I won't have to worry about blowing the rear end out if I have to run the spare.

Go over to BFG's website, look at the tires you want, make sure they will sit on the rim properly and plug them into that calculator until you find a tire that is the same size and will fit the width.

Have I thoroughly confused you yet?
 

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The other issue you have is each tire has an optimum rim size range. Just because you can shoe horn the tire on the wheel doesn't mean you are not pinching the sidewalls in to the point the outside of the tires are not making contact with the ground. Sure you can deflate them a bit to cheat, but then watch the TPMS go nuts.
Have I thoroughly confused you yet?
Yeah this can easily be confusing for some people. I'm sorry to say but you are mistaken with tire Section Width and Tread Width. Whatever "makes contact with the ground" calls Tread Width and it's got nothing to do with the width of the rim as long as you stay within the recommended wheel's width range for your tire. However the Section Width of the tire depends on rim's size.
SECTION WIDTH:
The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".
For example: a tire in the P205/60R15 size is measured on a 6.0" wide wheel and this size tire has an approved rim width range from 5.5" to 7.5" wide. The tire has a section width of 8.23" (209mm) when mounted on a 6.0" wide wheel. If that tire were mounted on all of the rims within its approved range, the tire's approximate section width would change.

Difference from Rim Width Approximate Tire
Measuring Rim Section Width
0.5" narrower 5.5" 8.03"
Measuring Rim 6.0" 8.23"
0.5" wider 6.5" 8.43"
1.0" wider 7.0" 8.63"
1.5" wider 7.5" 8.93"​
--------------------------------------------------------------------------
TREAD WIDTH:
Tread width is typically thought of as a measurement between the outboard and inboard edges of a new tire's tread design. Ideally it approximates the width of the tread that comes into contact with the road. Unfortunately measuring tire tread width isn't as simple as laying a ruler across the tread.

Good luck.
 

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Discussion Starter #8
Update - I passed on the all-terrain idea. Tire Rack flagged me when I ordered them, and mentioned the new overall diameter would be 29.something (I'm sorrry I can't remember right now) inches, which was 1.7" larger than stock. That would equate to about 0.85" above the current tire measure on one side. The tires I was going to order are these:

YokohamaÂ*Geolandar A/T-S

While 0.8" over my current tire did not reach contact w/ my strut assembly, that 29." mark did. Not wanting to chance my company vehicle, I ducked out of going for a larger / wider wheel.
Personally I believe the 245/60/R18 would be a great fit, but it would be close.

I did get a set of Nitto NT420S 235/55/R18 and love them. They look way more aggressive (in the street sense) than stock rubber. Ride quality is good too. If it was my dollar and my car, I would have went all terrain, but since its not, I did not want there to be a problem and have HR on my back. But really hope someone tries the Yoko's!
 

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Update - I passed on the all-terrain idea. Tire Rack flagged me when I ordered them, and mentioned the new overall diameter would be 29.something (I'm sorrry I can't remember right now) inches, which was 1.7" larger than stock. That would equate to about 0.85" above the current tire measure on one side. The tires I was going to order are these:

YokohamaÂ*Geolandar A/T-S

While 0.8" over my current tire did not reach contact w/ my strut assembly, that 29." mark did. Not wanting to chance my company vehicle, I ducked out of going for a larger / wider wheel.
Personally I believe the 245/60/R18 would be a great fit, but it would be close.

I did get a set of Nitto NT420S 235/55/R18 and love them. They look way more aggressive (in the street sense) than stock rubber. Ride quality is good too. If it was my dollar and my car, I would have went all terrain, but since its not, I did not want there to be a problem and have HR on my back. But really hope someone tries the Yoko's!
Nitto NT420S at the stock size? Your reasoning totally makes sense. But I was counting on you to prototype all terrain's at the 255 size for me so I don't screw up :)
My dealer is adamant that the 255's will rub but his credibility is strained. When you say "While 0.8" over my current tire did not reach contact w/ my strut assembly, that 29." mark did." - did you try a tire .8" over your current tire and have it rub or are you estimating? Thanks.
 

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You guys and gals want to have more aggressive look of your RAV and at the same time stay within its legal range? This is very simple. For vehicles with original size 225/65-17 go for 245/55-18 and for OEM 235/55-18 go for 255/50-18. The width of the wheel/rim should be not more than 8" with an offset not bigger than 45mm. In this case you should be OK with the fitment, speedometer accuracy, overall diameter, and will get a better look at the same time.
 

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You guys and gals want to have more aggressive look of your RAV and at the same time stay within its legal range? This is very simple. For vehicles with original size 225/65-17 go for 245/55-18 and for OEM 235/55-18 go for 255/50-18. The width of the wheel/rim should be not more than 8" with an offset not bigger than 45mm. In this case you should be OK with the fitment, speedometer accuracy, overall diameter, and will get a better look at the same time.
Unfortunately there is no aggressive, capable all terrain tire at my stock 235/55-18 nor 255/50-18 Alfa.
 
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