Pontiac Owners Club UK

I've gone for the aftermarket 17x9 snowflake rims on my '79 SE Trans Am.

They are nice lumps of metal, but 17x9 is not a good size for availability of tyres. I have 265/40s fitted now - and they suit the rims beautifully, but they are a full 1 inch smaller in radius than the standard 225/70/15s (25.3 inch diameter vs 27.4)- which means 1 inch less ground clearance (tricky on a lowered car) and they just don't fill the arches properly, too much free space.

There's nothing on the market I can find in 265/50/17, which would be the exact same 27.4 inch diameter as standard, but there are a few brands that make a 255/50/17 (27.0 inch diameter), which will do the job. This size gets discussed on Trans Am forums is the USA.

Most popular seems to be a Michelin rebrand known as Riken Raptor which is a nice 255/50/ZR17.

Overall choice/availability in this size seems to be:

• Riken Raptor - but I just can't find any supplier in the UK
  Nitto NT555 - can't find in UK and seems to be too much of a budget brand
  Yokohama ADVAN ST V802 - available in UK but made for performance 4x4s, might do the job but not ideal
  Kumho Ecsta SPT (KU31) - seem to be available in UK - but they are Kumhos!

So, my questions are:

Has anybody come across a UK seller of Riken Raptors, or an overseas seller that will ship them to the UK?

Has anybody come across another solution to tyres for the 17x9 snowflakes to give a good overall diameter?

Davy J had these rims and so might be able to help - not sure what tyre size he uses though. Black circles throws up a
265/50/17 tyre but it's a budget range tyre so not sure if suitable or not for your application.

As daft as it sounds I fitted budget tyres to my missuses BMW as they were a damn good price and the efficieny ratings they now have to declare were better than the top brand Michelins, Pirellis and Bridgestones! On all 3 criteria. They grip far better in the wet. So I guess sometimes just because they are budget doesn't mean they are crap.

Rims are 17 x 9, Year One Snowflakes. Tyres are KUMHO ECSTA SPT. Fronts: 245/40 ZR17 95 Y XL. Rears: 255/45 ZR17 98W.
Car has been lowered, don't know by how much exactly, but have about 3" clearance on front cross member. No rubbing with these tyres/rims.
Hope this helps.

Thanks for the replies gents.

I agree on the budget vs quality - many of the so-called budget brands are alter-identities for the big manufacturers, so you're often getting a Michelin/Bridgestone/Dunlop etc for ting tong money just because the sidewall has a different name moulded on it.

As for the sizes, mine are currently Falken 453 in 265/40ZR17 (a great sports tyre which I found better than Toyo Proxes TR1s for fast road and light track use on my old Jaguar XKR, they are a very good tyre).

That size fits fine with no clearance issues on a Hotchkis lowered '79TA, but they are a full inch smaller radius than original, and I want to fill the arches more and have a bit more sidewall because the low profile and arch space you get with the 40 profile tyres look - for me - a bit out of place on a 1970s car.

Update!!

After a ridiculous amount of time scouring every option in the UK and Europe I could find, plus a lot of refusals from the USA and Canada where tyres this size are easily sourced, I found a supplier willing to ship from the USA to the UK.

So, against this:

225/70/15 OEM diameter of 27.4 inches
265/40/17 current fitment diameter of 25.3 inches, losing a full inch (and a bit) ground clearance (the car is lowered so this causes issues) and arch fill.

Will soon have:
255/50/17 with diameter of 27.0 inches, just 0.2 inch radius less than OEM.

If anybody else with 17x9 snowflakes is interested in getting some of these, let me know. (Kumho Ecsta Sport is the brand, summer sport tyre)

Got there in the end. The 17" alloys are lovely but there just isn't anywhere in the UK - or Europe - that has tyres the right profile to fit them and look right. I eventually got what was needed imported from the USA, after a lot of faffing, but it was worth it.

Standard suspension with 15x8 rims and tyres. Nice stance to start with, a little higher at the rear than front which sets the car off nicely:



Hotchkis lowered suspension with 17x9 Year One rims and 265/40/17 tyres which are about 1 inch less in radius that standard. Although the car is lowered the tyres just don't fill the arches - loses under axle ground clearance as well:



As above but swapping the 265/40/17 for 255/50/17. Same tyre rolling radius as the original rubber, just needs a slight front:rear adjustment to lift the rear half to three quarters of an inch, but the arches are filled nicely and the comparison to original spec top picture shows the lowering to be a nice level. Also, going back up to 50 profile from 40 has made the ride SOOO much nicer.

Looks cool.