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Booboo

What tyre size would you put on an 8.5J rim?

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My new JDM wheels have finally landed and I am still undecided what size tyres to go for.  Wheel size is 18x8.5J. ET38.  Running Ohlins coilovers

Looking for recommendations for tyre size and not make. What size would you go for and why?

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Recommended sizes for an 8.5" wheel are 225 minimum with 235/245 as the ideal sizes.

I'd have a look at what sizes the tyres you want come in and use that to guide you. Personally I'd probably aim for 235 having run a 225 on an 8.5" wheel.

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You might want to check out prices on different sizes.  From Black Circles, prices of a PS4:

225/40 - £98.39
235/40 - £127.20 (+£115 per set vs 225)
235/45 - £162.37 (+£256 per set vs 225)

Here's a 225/40 on 8.5, I don't think the stretch looks too extreme.

IoUG4Ws.jpg
 

 

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Cheers guys

I have been looking at 235's (-3mm difference) but there doesn't seem to be too much choice on a 235/35/18 where I have been searching.  A 235/40 would be too large. An increase in diameter of 3.2%

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I run 18x8.5J. ET42 and the widest tyres I can run are 235/40R18 otherwise the tyre touches the spring mounts on the front stock shocks. I did have 225’s before but found the rims were getting too close to the tarmac for my liking. A bit too stretched in my opinion if you do track days.

As you’re ET38 you’ll have an extra 4mm between the rim and suspension. So you probably could go 245. I wouldn’t go any wider though otherwise you’d deffo have rub if you have stock suspension like me.

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Cheers Leeky

I'm on coilovers so OK on inner clearance.  Currently running 245x40x17 on 9J ET42 which I think look nice mounted on the wheel

I would like to go for a different width as a change from current set up. I'm thinking 225 would be too much of a stretch but probably the most playful set up. 255 I think is too wide for my needs so that leaves 235. Unless I'm missing a trick there doesn't seem to be too many options on 18's

Just wondering what others have found the best suited to a 8.5J wide wheel

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9 hours ago, Deacon said:

Recommended sizes for an 8.5" wheel are 225 minimum with 235/245 as the ideal sizes.

I'd have a look at what sizes the tyres you want come in and use that to guide you. Personally I'd probably aim for 235 having run a 225 on an 8.5" wheel.

What are your thoughts on having run a 225 on an 8.5?

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1 hour ago, Booboo said:

What are your thoughts on having run a 225 on an 8.5?

It's ok - it's what's on my winter wheel set up so I wanted relatively narrow. If they were normal use wheels I'd want to go for 235.

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I’ve decided to go for a 235 40 18 and there seems to be a fair amount of choice for around the same money

Discounting the more expensive PS4S as I want to try out another brand, spending approx. £100 a corner at Camskill will get a ContiSport Contact 6, a Goodyear Eagle F1 Super Sport, a Goodyear Eagle F1 Asymmetric 5, a Dunlop Sport Maxx RT2 or the 2021 released Bridgestone Potenza Sport

Decisions, decisions 😕

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Eagle F1 SuperSports are incredible but stock is short so hard to find for a reasonable price. I went Eagle Asym 5’s as they are 99% of the performance of a SuperSport but significantly cheaper and better in the wet.

I got 4x Eagle F1 Asym 5’s in 235/40R18 for £361.26 delivered from Black Circles.

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This morning I had fitted 245/35/18 on my 8.75j et35. Kwik fit had a deal on fitted £500. Its an epic tyre.

 

For what its worth a 245/40/18 rubs and looks awful dont ask me how I know.

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6 hours ago, KevinA said:

Stick to 35 profile on an 18" wheel.

Hi Kevin

A 35 profile would give 245 as the narrowest option on an 18.  I would prefer to go 235 on a 8.5J. Other than the obvious increase in rolling radius why would you stay clear of a 40 profile?

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Thanks for the pics Rich

The increase in rolling radius on a 245/40 is 28mm so not put that size into the mix. Cost increase on a 245/35/18 over a 235/40/18 looks to be around about £50 a set

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If you are going for an 8.5j rim then 40 profile is ok, anything over this will want to go 35, depends on how playful you want the car to be. Stock power then youy will be fine with a 235.

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I wouldn't recommend it but I used to run 195/45R14s on my G40 so don't ask what I would put on them. :) On a serious note I'd look at 235/40s on an 18x8.5.

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