Tyre Options

[brad]

Why would a lower speed tyre (92W) be more expensive than a higher speed (92Y) tyre?

Popularity? Same as a 235/45r17 is usually cheaper than a 225/45r17.

I buy from Tempe Tyres (mentioned them before). They are 15 minutes from home & always give good service to me.

Fitting, balance & disposal at most places will be $15-$20 per tyre. If they want more then they probably don't want your business. Some places are a bit up themselves & refuse to fit customer supplied tyres.

I'm happy to pay a small premium to buy locally ($10-15 tyre) if it means the tyre place stays in business & looks after me on other issues.

[tigger73]

Goodyear 225/40r18 F1-Asym2's are back in stock at Goodyear Croydon as of tomorrow!! $185ea

There's been a few people waiting on these to come back in... hit Rubal up if you need a freight price.

[donweather]

Hmmmm I spoke to rubal yesterday and he told me he wouldn't be getting more in for another month? meh?

[tigger73]

Hmmmm I spoke to rubal yesterday and he told me he wouldn't be getting more in for another month? meh?

I think they only just came back into stock in the country so he's getting a shipment delivered to the shop tomorrow. Give him a buzz before they sell out (again)

[donweather]

Ok here's some questions I'd appreciate people's opinions/advice on.

Looking at a new set of rims and tyres for my RS. Have narrowed it down to two sets of rims in 18*8 as follows:

Cades Bern 18*8 ET42, 9.9 kg per rim
ECS Alzor 349 - 18*8 ET45 11.1 kgs per rim
(Stock Neptunes - 18*7.5 ET51 13.4 kg per rim)

Both prices of the Bern and Alzor delivered to my door are about the same. Cades marginally more expensive around $35 per rim. So based on the above, should I choose the lighter rim and pay the slight extra, or given the fact the Alzor's are lighter than stock anyway, I'm getting an advantage over stock?

Secondly is tyres? Stock tyres are 225/40/R18, however going to an 8 inch wide rim as opposed to a 7.5 inch stock rim, I've noticed in some pics (see below) that the 225 wide tyre doesn't quite stretch well enough and you get the rim protruding out past the lip/edge of the tyre. I don't like the look of this nor the extra risk of gutter rash on your new rims. So I'm thinking of going with a wider tyre.....235/40/R18 to lessen the stretch of the tyre on the new wider rim. These size tyres are typically cheaper also than the 225s.

Will the wider tyre assist (or de-assist) in the handling/steering of the car (stock suspension and don't intend to lower the car as I tow a jetski)? Will a wider tyre assist (or de-assist) with lessening axle tramping?

I recognise my speedo will be slightly out with the the 235 tyre due to the slightly larger rolling radius (4mm on the radius, 8mm on the diameter).

Based on my calcs from the website below, here's the additional poke of the rims and tyres above

Cades Bern 18*8 ET42, 225 tyres - 9mm poke over stock, 235 tyres - 14mm poke over stock
ECS Alzor 349 - 18*8 ET45, 225 tyres - 6mm poke over stock, 235 tyres - 11mm poke over stock

My rough as guts measurements show I have about 10mm poke from stock rims and 225 tyres to the edge of the guards on the fronts and around 20mm on the rears. So the Cades with 235 tyres will likely extend out too much at the front by around 4mm? Should I be worried about this?

Custom rims, wheel tire packages for your ride - RIMSnTIRES.com



Apologies for the long winded post and varied and many queries, but I'd appreciate your thoughts and opinions on the above thanks.

[brad]

I'd go for the lightest, good quality rim you can possibly afford. About the only question I'd have on your two choices is what is the manufacture method - forged, high pressure or low pressure die cast or gravity - there are some variations on these types too.

You will notice the 1kg difference between your choices. The biggest mistake I have made on my car is the wheel weights.

235/40 is also a good choice for all the reasons you stated provided it doesn't make your actual speed greater than the indicated speed. Do you have any idea how the speedo reads now? ie 100kph on speedo is ???kph on the GPS. If your discrepancy is like my car then 235/40 will be fine. I have 658mm diameter tyres & 100=100. When I had 632mm tyres 100=90. 235/40r18 will be around 645mm.

A few of my mates would be able to pick a slightly slower turn-in / response from the wider/taller tyre but I doubt I could. Ride might be slightly plusher.

I have no idea about your axle tramp issues - have you put an insert in the dogbone mount yet?

Regarding offset, I had 17x8 ET35 & the rear was perfect but the front was out past the guards. ET42 should be close to perfect up front but even ET45 will have "the look".

What's the ball park money?

Before you pull the trigger, have you looked at TSW wheels? They do a nice line in rotary forged wheels. The weight is similar or less than the cades bern.

[donweather]

Cheers Brad. Manufacturing method...hmmmm...will have to get back to you on that. What's the best type of manufacturing method and the worst?

According to the link above, the diameter difference between 225s and 235s is 637mm vs 645mm. It also states "When speedometer reads 60mph (96.6km/h) actual speed will be 60.8mph (97.9km/h): 1.3% faster."

I have a dogbone mount insert but only the Superpro 70 (yes it's recommended only for diesel but didn't want to go for the 80 given the NVH). 70 has bedded down somewhat now so probably could consider the Superpro 80 now. I also have the Superaloy Lower Control Arms. All of this has helped but I'm still getting axle tramping around 4500 rpm+ in 1st gear (Stage 1 tune). However about to change tyres from Conti's to PS3's or Goodyears, both of which supposedly assist with reduction in axle tramping. Axle tramping is due to loss of traction isn't it? So with a wider tyre, won't it take more force to lose traction, thus wider tyre should reduce axle tramping?

Ball park money is of the order of $1500 delivered including duties/taxes etc for the Cades. Alzor's slightly cheaper.

Just had a real quick look at the TSW wheels. Only a couple that take my fancy and close to $2000. But thanks anyway.

[donweather]

Alzors are "Low pressure cast manufacturing process ". Cades are low pressure cast also.

[brad]

Forged are strongest but they are all perfectly acceptable manufacturing processes.

Stick with the 70 duro mount - I doubt the 80 would make a huge difference.

Do the wheels & tyres & then see what happens. With the lighter package there will be less that the dampers have to control.

What happens when you turn off ESP? I always get a better launch with ESP off.

[donweather]

Yes ESP off helps slightly, but nothing greatly. Conti's need to be real warm (like after driving highway speeds for an hr) and then they dont tramp. But around town they just don't warm up enough and tramp easy IMO.