club.liberty.asn.au

Interested in some wheels that come in 18x8.5/48. My GT-B is sitting at legal minimum height, and I want to fit 245/40s for speedo accuracy.

Can anyone tell me if this combo may scrub?

Also, stock offset is 55 - will that 7mm mess up the handling? It's the closest offset I can find.

ETA: I've got coilovers

Firstly you're not going to affect your handling to any noticeable extent. Obviously the different offset/track will affect the car in terms of geometry but nothing you really need to worry about.

The answer depends heavily on if you have coilovers too. I wouldn't bother trying this on stock suspension - you will destroy your guards/tyres.

18x8.5+43 on a 235/40/18 is IMO the ideal combo for these cars in terms of usability/performance/looks, however it's definitely advisable to do guard work for it.

18x8.5+48 on a 235/40/18 will 99% scrub at some point, likely at the rear quite badly, and the front possibly. You can mitigate it by running more camber, increasing ride height and doing guard work. Every tyre model will also sit differently and have more or less stretch.

You're bound to run into some sort of issue with 245/40/18 without guardwork, but it is definitely possible. You'll need some pretty aggressive rolling/pulling on front and rear, and probably shaving of the rear kick plate panel.

Measure your current setup eg guard clearance to tyre.

Put one wheel on a kerb to compress the suspension.

Re-measure, then put the oem wheel and your tyre specs into eg willtheyfit com and add the proposed setup to see if its within what your guards can accommodate.

You can do same at static height for inner clearance as well.

Fully flush with guard roll and top plate camber with coilovers is 235 40 18 8.5 +45

Maximum practical setup with the above plus more rolling, cutting & preferably adjustable rear lateral arms is 235 40 18 9.5 +38. 9.5 +45 will hit the rear trailing arms.

Fitment = commitment

Awesome, thanks for the advice fellers.

Forgot to mention, have coilovers.

I was looking at the inner guards (the plastic bits), and it looks like they're no less in the way than the guard lips. Was actually pretty surprised how little space there is in there... What's the go with those, reshape with heat gun?

I'd rather not bother with all this faff... Maybe I'm better off giving up on speedo accuracy and the 7.5/45 wheels are a better bet... What's the most common size for those? I'd prefer something on the wide side to protect the rims from gutters.

Oh yeah, how come I can't find a Gen4 section in Technical?

...

Kimmo wrote:Maybe I'm better off giving up on speedo accuracy and the 7.5/45 wheels are a better bet... What's the most common size for those? I'd prefer something on the wide side to protect the rims from gutters.

Actually, looking at that last post in the GT-B tyres thread, 235 is meant to be a bit wide for 7.5s... 225 okay? I've got 225s on the standard 7s, doesn't seem like too much tyre.

Kimmo wrote:Awesome, thanks for the advice fellers.

Forgot to mention, have coilovers.

I was looking at the inner guards (the plastic bits), and it looks like they're no less in the way than the guard lips. Was actually pretty surprised how little space there is in there... What's the go with those, reshape with heat gun?

I'd rather not bother with all this faff... Maybe I'm better off giving up on speedo accuracy and the 7.5/45 wheels are a better bet... What's the most common size for those? I'd prefer something on the wide side to protect the rims from gutters.

Inner guards... I've just let mine 'reshape' to fit over time . My fronts have enormous holes in them where the tyre sits but whatever, I honestly don't care. They don't really have much functional purpose for me any more anyway. Once you do guardwork they also will never sit right either so they end up hanging loose.

Go 225 on a 7.5 IMO. You'll be able to push a 235 on them with some tyres but play it safe with a 225.

So 10mm less offset won't have me scrubbing the fronts then?

Why the hell can't I find wheels with the same or more offset than stock? At least with too much offset you can add spacers; can't do anything about too little offset.

You’re missing key points about how it all works.

Standard road cars have to adhere to basic design rules, eg ADR, TUV, MOT etc.
Generally the standards regarding stock wheels and tyres include being able to run snow chains without hitting guards or the inner wheel well.

I’m not sure of the exact wheel clearance required for chains, but it’s probably in the region of +20mm all round as regards the stock tyres which happen to suit the width of the stock rims.

Therefore that dimension (+20mm either side) can be added to a proposed setup on eg willtheyfit com.

Offset is simply the standoff of the rim centre line from the mounting pad.
Any wheels with different widths and the same offset will still have the same centreline.

So a 235 40 18 on a 9.5 +35 rim will fill the guard with tyre similar to a 235 40 18 on an 8.5 +35 rim.
The former rim will poke an extra 1/2”, the tyre will be more stretched in comparison so the 8.5” rim.
But the tyre shoulder & tread will be in the spot in relation to your guards, inner and outer.

Either way, if you use your current setup as datum points for fitment, you can extrapolate what might work for you.

You can also inspect wheel mfg spec sheets, eg on the rays, work etc sites.
Eg fitments in 5x100 for Japanese cars. You’ll often see a certain type of run of the mill rim in conservative fitments, eg 18 8 +40.
That’s gonna fit without work assuming the tyre spec matches.

Finding exactly what suits you should be hard work to a degree, that’s what is so rewarding about it, ultimately.

bigBADbenny wrote:You’re missing key points about how it all works.

Yeah nah, I don't think so... Although the thing about snow chains is appreciated. I know what the numbers mean. Didn't know about willtheyfit.com though, thanks.

I didn't make it clear that the wheels I'm considering come in 18x8.5/48 or 18x7.5/45, and perhaps I wasn't clear that in addition to clearance, I'm concerned about scrub radius.

With the standard offset at 55mm, 7 or 10mm might not sound like much, but to me it's not inconceivable that this could cause the car to get a bit squirrelly under power or braking. And if that's the case, that'd kinda defeat half my purpose of fitting aftermarket wheels, ie improving handling by reducing unsprung weight.

It actually kinda boggles my mind that I can't find any aftermarket wheels to match the stock offset - IIRC it's illegal to change the track without an engineer's certificate, so there's all these cars getting around waiting to get defected on a cop's whim. What's the deal with that? Is 55 an unusually large offset, or does the aftermarket just not give a shit?

You need to be more specific with your intent.

Are you after a certain width?

Have you checked your states laws regarding wheel and tyre modifications.

I’m on 235 40 18 8.5 +35 with some poke, stock alignment and generous finger gap. King pin axis is somewhat corrected with maxed inwards camber tips. So far no dramas with enforcement but the car looks mature and I don’t drive like a knob. No squirreliness.

Furthermore yahoo.jp is rotten with weak offset aftermarket rims.
Personally, I’d check out advan connoisseurs which come in 18 7.5 +50 and still manage to look concave.

Ditto for most vanilla spec brz/86 rims and prius.

Also
https://m.facebook.com/groups/673916309 ... =bookmarks

Cheers for the info. I'm in Victoria; I think the only relevant laws here just relate to changing track.

Well, the intent is to find something a couple of kilos lighter than stock, something in a sexy 10 spoke like Enkei PF01. Not really after anything much wider, but as mentioned I'd prefer the tyres to be at least a tad wider than the rims to protect against gutter rash. So I guess that means 225s on 7.5s?

Thanks for the heads-up on the 50mm offset of the Advan Connoisseurs, I'll check em out.

ETA: didn't find the Connoisseurs, but Advan has quite a few in 50mm. But damn, they're spendy... I thought I saw the Enkei PF01s for like half the price of these Hopefully that FB group is nice and busy.

bigBADbenny wrote: King pin axis is somewhat corrected with maxed inwards camber tips.

Hmm, since the whole hub assembly pivots on the end of the lower arm when you adjust the camber, doesn't the bottom of the tyre just move outwards along with the kingpin axis...?

With coilovers camber is adjustable top and lower of the Mac strut.
Therefore with a stockish alignment, top mount all the way inward, the strut is more aligned with the tyre centreline on the ground.

Eg the car points around 10mm lock to lock, stationary, and tilts a little with dynamic camber:

What I “lack” in static camber, I make up a little with caster offset lca bushes.

Hm, my coilovers don't seem to have any lower camber adjustment beyond the typical hole slop situation... Looks like these are them.



...And does this look kosher to you?



Is that on purpose maybe, since the road's camber is generally more pronounced under the left wheel...?

The upper bolt on the knuckle mount is an eccentric camber adjuster.

Eg the paint marks should line up or be marked after an alignment

Of which you car may be requiring.

I use Rocky at Donnellans in Collingwood

Bcs are mainly for looks imho.

I saved up and got Shockworks which are a spectacularly versatile handling upgrade.
Our 2.5i is on Koni sport yellows but new kyb’s and springs would do.