Tyre Options

[brad]

plug some figures into the link. 7.5 ET51 has less brake clearance than 8 ET42. Orange profile is original, green is modded.

eg: when I had 17x8 ET35 they poked outwards too much. In order to bring them under the guards I was going to machine 10mm off the inner wheel face where it mates with the hub. Resulting ET would have been 45. I agree, it makes no sense.

Edit: If you old rims =18x7.5 ET52 and the new rims = 18x8 ET42 and the design / proportions of the rim were exactly the same then the ET42 rims would have about 3mm extra clearance between the spokes & the brake caliper.

[Martin]

Stock brake caliper to spoke clearance should not be an issue at all
(the stock caliper is all on the other side of the disk rotor)

It did have problems with my BBK calipers, the Neptunes hit them
I had another set of wheels that needed a 3mm spacer - sold them
The Audi RS3 wheels have spokes with good clearance - no spacer needed

[donweather]

Well I just ordered my Alzor 349 18*8 ET45. They will be on a slow boat from the USA so I'm not expecting them to land in Brisbane for another 2 mths+.

Now the wait begins.

Still deciding on whether to go with the stock tyre sizes (225/40) or go that little bit wider (235/40) to avoid the rim poke past the tyre wall look (which I don't like visually or protective for the rims).

[donweather]

These are what I've used

Michelin PS3
Lovely all round tire, lasts well, great grip in both dry and wet, not very noisy
When going hard the initial turn in response a little soft

Goodyear F1A2
A little more dry grip than the PS3, maybe a little less wet grip than PS3
Last very well but more noisy than PS3
When going hard they are simply awesome, brake hard, turn response is excellent, makes your day
Given the price and performance of these tyres, it's really hard to consider others

Conti CS3
Very hard wearing, pretty noisy (gets bad when below 50% tread), they often slam through pot holes
Need to pump them up pretty hard to get the turn in response I wanted
Very good level of dry grip - wet was ok also
The only point where they really shine is the km you get out of them (with good level of grip)
Generally I would not buy these given the price

Bridgestone Potenza 040 & 050
High grip level in the dry, on wet days needed to get them warm first
Prone to axle tramp on hard launches
Turn in is good - braking is great
Price is simply awful

Maxis M35
I had these on the wife's Mazda3
Surprising tyre - does everything ok - lasting well - price was ok
Hard launch was better than the 040 (no axle tramp)

Continental Contact MC5
We got these in a "pay for 3 get 4" deal - they are on the Mazda3
Surprising tyre - does everything ok - lasting well - price was good

Well after fitting Goodyear F1A2 to my Occy RS on the weekend and testing them out today, I have to say my axle tramping is all but eliminated and I now have my full first gear back in action thank goodness. It's like night and day between the Goodyears and Conti's when it comes to axle tramping!!!!

Very happy indeed.

[Martin]

Good to hear you're happy with them

I would have to revise my opinion of the Maxis M35
My wife is a very gentle driver, hence they are lasting ok for her
But I'm on good terms with the local tyre shop,
they don't like selling the M35 due to poor km/life and associated customer dissatisfaction
They find is easiest to sell them during the pay for three get one free specials

[donweather]

I still can't believe the night and day difference. After the mods such as LCAs and dogbone inserts to try and eliminate the axle tramping, the biggest bang for buck in eliminating the axle tramping has by far been the new tyres.

Rolling resistance seems a little higher on the Goodyears but?

[brad]

I still can't believe the night and day difference. After the mods such as LCAs and dogbone inserts to try and eliminate the axle tramping, the biggest bang for buck in eliminating the axle tramping has by far been the new tyres.

Rolling resistance seems a little higher on the Goodyears but?

You got new rims as well. Is the new rim/tyre combo lighter than the old one?

[donweather]

You got new rims as well. Is the new rim/tyre combo lighter than the old one?

Yes, but not by a significant amount. Maybe 1-2kgs per corner tops. So 10% lighter say.

[brad]

1kg unsprung is worth 2-4kg sprung (depends who you're talking to), so there would be a benefit but good tyres should always be the first mod IMO.

[GTR27]

That's quite a saving in unsprung weight as brad said. Would actually make a decent difference even if you had the same tyres, although I suspect tyres made the biggest difference.