Rear arch scuffing? Ideas please?

rpjg_1975 · May 16, 2008

Just wondering if anyone has had a similar problem.

Am currently running Boxster alloys on my 944 and seem to be getting scuffing on the rear tyres when I go into a corner even at low speeds, i.e 20 mph with a passenger in. Only seems to be the passenger side though. Anyone got any bright ideas how I can solve this problem or am I destined to have problems with these wheels?? Am running 255/40/17 tyres on the rears and the ride height seems to be the same both sides.

Thanks for any assistance

peanut · May 16, 2008

As far as I know you can't run 17" cup1 alloys on a early 944 the wheels have a totaly differant offset to a Lux wheel.You can put them on an S2 .

mik_ok · May 16, 2008

The passenger side rear wheelarch has less clearance than the drivers side - a point discussed regularly on here - legacy of pre-CAD modelling techniches.

Someone who knows about rolled arches will be along soon - I'm sure the later cars had rolled rear arches which better accomodate wider rims/tyres.... maybe worth a search. I believe you can have non-rolled arches rolled over (?)

cytefx · May 16, 2008

my can had rims on that had an offset of et50, they did not rub (it looked like they may on full lock) but were to far in the arches for me, I have replaced them with a set of replica cup 2 alloys with the correct offsets (et23)

I have the old alloys for sale at present, they are split rims from what I can see (think only 2 piece) but they should fit a post 86 car or the s2, as they have a offset near to my alloys.

pauljmcnulty · May 17, 2008

As far as I know you can't run 17" cup1 alloys on a early 944 the wheels have a totaly differant offset to a Lux wheel.You can put them on an S2 .

The later wheels will sit too far in - and need 30mm spacers. So, they shouldn't stick out any further. Rolled arches only on S2/turbo, is the car lowered - causing the wheels to rub?

I'd buy some nice teledials! [&:]

rpjg_1975 · May 17, 2008

The car isn't lowered as far as I know

I have actually been debating whether or not to get some other wheels for it but they really suit it [

] so I am a bit reluctant to. Maybe that will be the only thing to do.... one thing does spring to mind? Would it be any better putting narrower tyres on the backs? I doubt if that would make that much difference though if I am thinking correctly. I have added a couple of pics to show the wheels in the arches.

Peter Empson · May 17, 2008

That's a shame as it looks really good. You could try to get the arch rolled, although I asked my bodyshop to do it to mine and apparently it was really difficult due to the thickness of the metal used and its strength. However there are threads about diy'ing it on rennlist so might be worth a search there. You could also try a different suspension set up with a little more negative camber if it's only just touching? If in doubt of exactly where and how much it's rubbing put some masking tape around the arch and go for a drive.

peanut · May 17, 2008

ORIGINAL: rpjg_1975

The car isn't lowered as far as I know

I have actually been debating whether or not to get some other wheels for it but they really suit it [] so I am a bit reluctant to. Maybe that will be the only thing to do.... one thing does spring to mind? Would it be any better putting narrower tyres on the backs? I doubt if that would make that much difference though if I am thinking correctly. I have added a couple of pics to show the wheels in the arches.

looks real nice. How the heck do you keep that colour looking so clean ?!

A lower profile tyre would give more clearance but it would alter your gear ratios ,quicker acceleration but lower top end.You could ask a machine shop to shave 5mm off the mounting face . There is probably enough material there to do it safely but you'd need to take advice from a wheel manufacturer

The other possibility might be to swop some transmission/suspension parts around with a later car.I don't know what would be involved or if its feasible but must be worth a look at. I would ask our friends across the pond who are most likely to have solved this problem before.

pauljmcnulty · May 17, 2008

It does look as though it's sitting a long way out to me. Are there spacers - I guess there must be unless you've got different hubs - and how big are they? Might just be a matter of going for a slightly smaller size? IIRC Lux is 23 offset, the Boxster wheels 50 something. You should have around 30mm shims, and I'd rather fit 5mm smaller than shave 5mm off the wheel!!

Diver944 · May 17, 2008

You don't say what size the rear wheel and offset is (stamped either side of the valve) but if it's like mine I am guessing it will be 8.5" wide and offset of 50. This should fit a late offset car with no problems, here's a quick pic of mine on an S2 that doesn't have rolled lips.

Maybe your rear suspension is really soft? You could fit narrower tyres that have the same diameter ie 235/45/17 is only 1% different

mik_ok · May 17, 2008

Well you certainly don't appear to have early offsets ~ if you did these wheels would be sticking in a lot. Actually - worth checking that you don't have early offsets with bolt-on spacers fitted? (If you do then a smaller rear spacer would sort the job).

Some good suggestions regarding masking tape to identify where it is touching the arch, and to consider adding a couple of degrees negative camber to the rear.

Checking the Toyo website, they recommend a 235/45/17 for anything up to a 9" rim width, so they would just fit on and cause no change to your gearing.

rpjg_1975 · May 17, 2008

Right....

Definitely no spacers fitted.

Hubs are 50mm from disk to face of hub.

Wheels from the point where they bolt to the hub to the front of the wheels are... fronts 75mm and rears 100mm

Hope this helps a bit?

Is clear where it is catching on the arch as it is actually marking the arch lip. Is to the rear of the centre of the wheel arch.

Do you think putting a narrower tyre on the rears would solve the problem as I don't really want to spend out on new tyres then find I have the same problem, for obvious reasons.

Thanks for all the replies so far.

Starting to think I may be better off getting rid of these alloys and getting something with the right offset. Seems a shame but maybe the easiest way of solving the problem?

pauljmcnulty · May 17, 2008

Starting to think I may be better off getting rid of these alloys and getting something with the right offset. Seems a shame but maybe the easiest way of solving the problem?

I don't get this. Your hubs should fit wheels with 23mm offset. If the 17's have over 50mm offset they should sit 30mm INSIDE, not stick out. Are you sure you don't have proper spacers fitted, rather than shims? Or, do you have different hubs? Or, am I being thick and missing something! [8|]

Diver944 · May 17, 2008

I think we need to see a clear picture of your wheels as it is unclear from the avatar pic exactly which ones you have. Genuine wheels will have the width and offset stamped by the side of the valve, aftermarkets are blank.

I am guessing that you actually have aftermarket Cup3 wheels and not Boxster twists. As far as I am aware there are no aftermarket Boxster twists so I think you have aftermarket Cup3's with an early offset, yet you have one of the changeover '87 model cars with late offset hubs. This is the only way I can think your wheels stick out so far

These are Cup3s also called 'Turbo look'

These are Boxster twists also called 'Carrera 2's'

Peter Empson · May 17, 2008

ORIGINAL: pauljmcnulty
I don't get this. Your hubs should fit wheels with 23mm offset. If the 17's have over 50mm offset they should sit 30mm INSIDE, not stick out. Are you sure you don't have proper spacers fitted, rather than shims? Or, do you have different hubs? Or, am I being thick and missing something! [8|]

If it's a post 85.5 (i.e. oval dash) car then it has the later offset surely?

I suspect a 245 tyre may be sufficient if it's only just catching, but each tyre design will have different shaped shoulders so this is something else you may want to look at. Perhaps it's worth trying to find a friendly tyre place that can put aside some used 245 tyres from another car, the cost to swap them over shouldn't be too great and they're on the promise of a set of new tyres if it works so might be keen to give it a go.

rpjg_1975 · May 17, 2008

Ok, from those two pics posted it would appear I have got the aftermarket cup 3 wheels. I will try to get a couple of pictures of the wheels and post to confirm but that definitely sounds like that's what I have got.... damn!!

cytefx · May 17, 2008

hi,

mine is a 86 car and I have the early offsets (just had to get a replacement set of rims as mine had the late offset rims on when I brought it)

they used to stick in to the arch a long way, now they are flush (and do not rub)

if you remove one wheel it will be stamped inside the et number, if its a later car (i.e. 87 on (think some late 86 also had the larger offset) then the number will be around 50, id its early then it will be more in the region of 20.

the rims i took of my car were 9.5x17 with a et of 50 and now I have 9x17 with an et of 15 and they are perfect.

I have photos of them somewhere but not uploaded but I can email them if you wish to see a early car with late offset rims.

John

rpjg_1975 · May 17, 2008

Latest wheel scrubbing issue update....

It would appear to be a combination of the good old wheelarch difference and a slightly different tyre sidewall profile to be causing the problems. Driver's side is a Falken and passenger side is a continental. Appears to be a more 'square' sidewall profile on the conti. Out of interest I am gonna get my mate to swap the tyres over tomorrow and see if I still have issues......

will keep updated.

By the way, have advertised the wheels in the for sale section. Open to offers, but need something for mine to sit on even if it was teledials [8|]