The Impreza Turbo I have just made an offer to purchase has OZ Polaris wheels with a 50mm offset, car drives ok and doesn't seem to be fouling anywhere. Are there any other problems likely to result due to the 5mm offset difference?

Not really. The 16 inch wheels have an offset of 52.5mm, but are marked as 53mm.

The original 15 inch alloys were 55mm, as were the 17 inch alloys available from Speedline at the time.

Since then, a number of other wheels have come on the market, with offsets from 40mm upwards.

Generall rule is that anything of 48mm and above will be fine, without too much effect on handling and steering.

Even 45mm offset wheels will fit fine without requiring rear arch mods, but you are getting close to the limits of what will fit under the arches, especially with lowered suspension.

At 45mm, the track will be 2cm wider than that of a car running 55mm offset wheels. Not a huge amount, but enough to make the steering a bit heavier, and the car more prone to tramlining etc.

Anything less than 45mm offset (esp with 18 inch wheels), and you are looking at having the rear arches turned in to give enough clearance, or bump stops fitted to prevent full suspension travel.

I have spoken to the current owner who tells me that the wheels were supplied by Motorsport wheels in Stockport.

Called them direct, and although the guy I spoke to seemed to know the particular wheel he was unsure of the exact offset measurement for the wheel. The wheels allegedly were made in a batch of about 400 sets all supplied direct to themselves especially designed for the impreza Turbo by OZ. They come to them marked on the box as IMPREZA TURBO.

John I am interpreting the above reply. That if they fit without fouling anything, and in the knowledge that they were specifically supplied to fit that model then they are probably OK, but may give minor alterations to the handling characteristics of the car.

Have I a) Missed the boat.
or b) On the right bus.

I have been looking at new wheels for the Impreza and a couple of people have the Oz Polaris listed as an Impreza Fit. They dont list any other OZ wheels though. So it sounds like they did do it specially for the Impreza.

Please excuse me for my ignorance but what exactly is the offset and how does having a low offset (one less than recommended) affect the handling?

Mike,

yes you are correct http://bbs.sidc.co.uk/smile.gif

Andymac - Offset:

If you looked down on top of a wheel (ie you would see a rectangle), the offset is the distance between the real centre of the wheel, and the plane where the wheel mounting surface actually is.

Wheels with a lower offset have the mounting surface is closer to centre line of the wheel, and when mounted on the car, will mean that they stick out further into the wheel arches (ie give a wider track).

Up to several mm, this doesn't really make much difference, and you would be hard pushed to spot it visibly. However once you get to 10mm and above (ie 1cm) the difference becomes very apparent visually, and will result in heavier steering, and affect the handling (particularly at the limits).

So, fitting a set of 16" OZ SuperTourismo's which have a 50mm offset as the nearest size should be okay then?
By the way, if anyone is interested, I have some information on a set of wheels that may appeal to some of you. I was speaking to the manager of my local parts and accessories shop, Checkpoint in Aberdeen, about the OZ wheels, and he reckons that some time this year, OZ will be bringing into the country 17" OZ SuperTourismo's, with the correct offset for the Impreza, and they will be in gold.
That's more or less the same wheels as on the 22B, isn't it?

The 22B has BBS wheels which also seem to be available in silver for as an option on the Legacy B4.

I think the OZ wheel you mention is quite different?

Stuart

Thanks John

I have recently fitted 17" Rimstock Monza wheels in gold which have a 45mm offset on MY98 saloon. The tyres are 215/40 x 17 Falkens. The only slight problem is a slight catching of the rear wheels on the arches when hitting bumps or fully laden, this might not happen if I had fitted 205/45 x 17" tyres. I have also noticed no difference in handling or tramlining over the original wheels/tyres. The looks make up for the slight catching!!!

I'd be pretty wary of the tyre rubbing the arch just in case it makes them go bang sometime. Might be damaging the tyre sidewall.

JHall,

I spoke to Wheel Base yesterday about the OZ ST rumour, they tell me that these wheels will not be available, OZ don't think there is a market for them. If true, this is a shame cause I'd love a set.

Have you heard anything different?

Regarding the slight catching with the rimstock wheels/215/40 x 17" tyres, In response to the posted reply, I have have checked the tyres very throughly and I can find no marking on the tyres, as I said it is only a slight catching and only when the car is fully laden.