Tyre issues

[andystevo]

My car is currently running Toyo Proxes, 225/45 WR16s on the front and 245/40 YR17s on the rear.
The tyres are a few years old now although in good condition with plenty of tread left.
However, I would like to return to the correct sizes and speed ratings.
A (not so) quick trawl on the internet generated nothing, at least not in the UK.
Main sticking point appears to be the speed rating. Plenty of W, a few Y but no Z. The fronts especially difficult.
I found a few suppliers in the States able to do a complete set of Bridgestone RE010s for approx. $1000, but not sure I've got the nerve to ask about shipping to the UK, never mind import duty and tax.
Any suggestions?
Thanks, Andrew

[duncan]

Andrew,
Looking at the Black Circles; for matched sets they list Yokohama Advan AD08 in 215/45x16" and 245/40x17" [OEM size] and for the next combination up of 225/45x16" and 245/40x17" all in a W rating [168mph].
Question on speed ratings - for a Z rating [+150mph] what is regarded as it's max rather than an intermediate point at which it is safe?
Dependent on how good your tyres are, particular sizes and makes come and go, so it may be worth waiting. I run Conti Sport Contact 2s and can normally see listed 255/40Zx17" but rarely the 225/45x16'. Today the reverse no 17" but the matching 16" is available.
Whilst Blackcircles has worked for me in the past. I can't comment on AD08s as I've never bought them, principally because one or other of the paired sizes wasn't available at that particular point in time.
You may find it advantageous to go into a local independent as they should have lists from a range of wholesalers who often have elusive sizes and makes remaining in stock.
Best of luck.
Duncan

[nobby]

As Duncan says your local independent dealer is the best place to review tyres.
I run the 17 and 16" OEM combo and use Bridgestone Potenza's RE050's

[Kaz-kzukNA1]

Hi, Andrew.
You are going to struggle finding the ZR category tyres (over 240km/h, strictly speaking, it’s a category and not a speed rating) because that symbol is from very old days.
For ZR category, there was even a rule that there was no need to display the Load Index (LI) symbol.

The modern tyres similar to the ZR category are rated as;

[Under specified conditions]
V: 240km/h max
W: 270km/h max
Y: 300km/h max
(Y): New Y rating. Over 300km/h


There is misunderstanding among many people around the speed rating.
Some even claim that one can’t fit a tyre with the speed rating lower than the max speed of which the very car is capable.

The speed rating is tested under many conditions (forgot the details, it was long time ago...) including the load specified by the LI.
It is almost impossible to keep applying the amount of LI specific to the very tyre for the specified duration at the max rated speed under several conditions unless you have access to the tyre dyno/simulator (you will be impressed if you have a chance to visit the tyre manufacture).


There are several discussions regarding the speed rating of a tyre related to the car insurance policy.

Each car models have different weight distribution so it’s impossible to check the minimum required speed rating for each corners apart from the spec of the tyres in the owner’s manual and hence, some of the car insurances may specify that the policy holder should not use the speed rating lower than the OEM one.

I think it was last winter when we had lots and lots of snow and people started fitting the winter tyres to their cars for the safety reasons and that was when the insurance industries had to make it clear to the policy holders that it was fine to make claims even if their cars were fitted with the winter tyre that was normally below the OEM speed rating.


The trend in Japan has shifted to Neova AD-08R but still the original AD-08 is a good choice for our NSX due to it’s very stiff side shoulder.
For some reason, in UK and possibly in other countries as well, AD-08 is classified as Track day tyre but in Japan, it's been designed for street usage.
My personal experience below.
I drive every day and just drove through flooded area around Oxford, Cotswold, etc over the weekend with no tyre issues.

http://www.nsxcb.co.uk/entry.php?697-Advan-Neova-AD-08-Part-2

If you found that the AD-08 is out of stock at your local dealer or even on the internet, just call Yokohama Tyre UK.
They checked the next delivery schedule for the specific size over the phone for me several times in the past and very helpful.
Best to plan well in advance as sometimes, it could be out of stock for many weeks.


As a side note, tyre is another engine on our NSX so please invest in it.

Kaz

[andystevo]

Great, thanks guys.
Kaz, just checked out Black Circles. AD-08Rs currently in stock (set of 4 available for £579).
Might organise new tyres in the meantime and ask my local garage (Black Circles registered) to hold them until MOT time at start of March.
Would also appreciate your opinion of my car's current suspension settings (not standard) - will post separate thread soon.
Andrew