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Best Tire Size

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Old 01-23-13, 12:18 PM
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Best Tire Size

Hi Guys, My Dad bought me a set of Motegi Racing Wheels for my 90 T2. I'm pretty sure I asked for 17" but he bought me 18" wheels. They are 18x8 +35. I was looking through other posts trying to figure out which size tire would be best to put on them but didn't have much success.
So, which size tire would look/work the best?

Best Tire Size-motegi-mr117.jpg
Old 01-23-13, 03:58 PM
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After more digging I found that it would have been easier if the rims were 17s.

Anyway, the sizes I found pics of were all mounted on FDs.
215/40, 225/40, 245/40, and 255/35

Doesn't anybody use 18 inch wheels on FCs?
Old 01-23-13, 04:07 PM
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Most people think 18s are just too big for a 2nd gen so they're not that popular unless you have a wide body. I would go with the 245-40-18
Old 01-23-13, 04:26 PM
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You will likely need to roll your rear fenders and get wheelspacers to prevent rubbing.

May also need to roll the fronts depending on if they rub.

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Old 01-23-13, 04:40 PM
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well with any tire/wheel modifications, you'll want to get as close as you can to the stock tire circumference as possible. (rule of thumb is to go no bigger than 3% up or down)

a 245/40-18 would be more than 4% taller, and would result in false readings from the speedo, and worse yet it would RAISE the car about ~0.7 of an inch (which looks terrible, is bad for handling, and just over all not a good choice)

a better match would be either a 215/40-18 which is less than 1% taller than stock. or a 235/35-18 which is also less than 1% taller than stock.

depends of what you'd like. with a 235/35 all around you'd probably have to roll the front fenders.

a 215/40 is a safer choice, but you'd get less contact patch.
Old 01-23-13, 08:08 PM
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Originally Posted by beachFC
well with any tire/wheel modifications, you'll want to get as close as you can to the stock tire circumference as possible. (rule of thumb is to go no bigger than 3% up or down

a 215/40 is a safer choice, but you'd get less contact patch.

Wow, thanks for the info. Maybe my best bet would to return the wheels and trade them in for 16s or 17s. The 18" tires are rather costly also, although cost really isn't a problem, but why spend so much money if I don't have to.
Old 01-23-13, 10:18 PM
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Originally Posted by beachFC
well with any tire/wheel modifications, you'll want to get as close as you can to the stock tire circumference as possible. (rule of thumb is to go no bigger than 3% up or down)

a 245/40-18 would be more than 4% taller, and would result in false readings from the speedo, and worse yet it would RAISE the car about ~0.7 of an inch (which looks terrible, is bad for handling, and just over all not a good choice)

a better match would be either a 215/40-18 which is less than 1% taller than stock. or a 235/35-18 which is also less than 1% taller than stock.

depends of what you'd like. with a 235/35 all around you'd probably have to roll the front fenders.

a 215/40 is a safer choice, but you'd get less contact patch.
I like the raised look plus it's highly functional for a daily. I had 225/65/15's on my fc and I could take a full sized curb with no scraping.
Old 01-24-13, 12:09 AM
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Originally Posted by philiptompkins
I like the raised look plus it's highly functional for a daily. I had 225/65/15's on my fc and I could take a full sized curb with no scraping.
Wow, man that's pretty crazy hahaha.. but yeah, rasing the car also raises the center of gravity, which in turn has a negative effect on handling. I've never met anyone that likes RAISING their car, to each their own I guess!
Old 01-24-13, 07:33 AM
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Originally Posted by beachFC
well with any tire/wheel modifications, you'll want to get as close as you can to the stock tire circumference as possible. (rule of thumb is to go no bigger than 3% up or down)
.
Would it be better to go down a little in size or go a little up?
I was using the tire size calculator and if I put 215/40-18 on the wheels, the tire should be physically about the same size as stock and the speedometer should read 60.2 when doing 60.
215/35 would be a little smaller and the speedometer would show 58.2 when going 60.
Which is better? A little smaller or a little bigger.
Old 01-24-13, 08:18 AM
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The 215/40 puts you much closer than the 35 series, I'd go with that.

I'd also pay more attention to how accurate it is between 20 and 40 mph because that is where the majority of speeding tickets fall.
Old 01-24-13, 10:20 AM
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Originally Posted by beachFC
Wow, man that's pretty crazy hahaha.. but yeah, rasing the car also raises the center of gravity, which in turn has a negative effect on handling. I've never met anyone that likes RAISING their car, to each their own I guess!




Not everyone needs to race their cars to get between work and home. Some people prefer the smoother ride of a larger tire, and that's still perfectly acceptable. I like the way the stock wheels/tires ride. It's nice and smooth, and the car handles well enough that I don't need to sacrifice ride comfort for that 0.001% chance I need or want the car to handle like we're flying down a mountain at 180.

My vote is for the 215/40's too. I used to hate having to mount anything with an aspect ratio less than 40.
Old 01-24-13, 10:27 AM
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The 35mm offset is about max for a 8.0" wide rim. If you have coilovers that would help the fitment in the front. I would think the best size would be 225/40-18 front and rear.
Old 01-24-13, 10:57 AM
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sell and buy something that fits!
Old 01-24-13, 01:28 PM
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I personally run 225/40/18s up front and 255/35/18 in back. Seems to work for me.
Old 01-24-13, 02:08 PM
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thanks for all the help guys. I'm going to look around and put a price on the tires.
I can't take them back..........they were a gift

thanks again

ashley
Old 01-24-13, 02:31 PM
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Search multiple tire sizes. More common sizes are usually cheaper. For instance, 225/40/18 are about $50 cheaper than 215/40/18. Fiddle with the numbers and see what you can come up with. It's not like the Rx7's speedometer is very accurate anyways. With stock tires and differential, I was 6 mph off around 15 mph (reading 21) and it got better around 60. I was then reading a couple mph off again around 70 (going 72).
Old 01-24-13, 02:35 PM
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Originally Posted by AGreen
Search multiple tire sizes. More common sizes are usually cheaper. For instance, 225/40/18 are about $50 cheaper than 215/40/18. Fiddle with the numbers and see what you can come up with. It's not like the Rx7's speedometer is very accurate anyways. With stock tires and differential, I was 6 mph off around 15 mph (reading 21) and it got better around 60. I was then reading a couple mph off again around 70 (going 72).
That is very true, But upsizing tires not only effects the speedo. Gearing will be slightly awkward as well. everybody says FC's are geared too tall, a bigger tire will only make this worse.
Old 01-24-13, 04:36 PM
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Originally Posted by AGreen
Search multiple tire sizes. More common sizes are usually cheaper. For instance, 225/40/18 are about $50 cheaper than 215/40/18. Fiddle with the numbers and see what you can come up with. It's not like the Rx7's speedometer is very accurate anyways. With stock tires and differential, I was 6 mph off around 15 mph (reading 21) and it got better around 60. I was then reading a couple mph off again around 70 (going 72).
Thanks, I didn't know that. I just found a nice dunlop for like $225 for the 225/40-18 and the same tire is $295 for the 215/40-18.
Big difference. I'll probably go with the 225/40.
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