The Wheel Police

Another useful bit of Zed trivia came up on the forum in Sept 2002 on this thread. Stock wheels are "handed" - that is they're different on the left then the right. You can have hours of harmless fun wandering round at meets spotting owners who don't know this and have mismatched wheels (like I did for 3 years before Nelson MainFella posted that thread). I was lucky as I still had 2 L and 2 R but I have seen one or two who had 3 R and 1 L (or vice versa) which left them in a bit of a quandary.

The Wheel Difference Part 1

Jspec has the same wheel all round which take the 225/50 R16 tyre. They're 7.5" rims with a 45mm offset. Stamped into the rim you will find: L 40P05 (for the left side wheel) and 40P00 R (for the right).

both wheels are RH
RH wheel ok at the rear but front wheel is LH

To quote from that excellent publication, The Enthusiast's Companion: "The style of the 300ZX's cast aluminium wheels is directly related to the braking system, for it was evident that they must provide for brake cooling. A chosen design has five narrow spokes and is unidirectional to encourage airflow between them." and "Distinctive cast alloy wheels are attractive and functional, designed to cool exposed brake calipers".

Another good reason to stay stock!

The Wheel Difference Part 2

The Enthusiast's Companion also notes the difference between the J spec and other markets. As above, Jspec has the same size all round but the UK has the above as front tyres and wider wheels at the rear which take 245/45 R16 36psi. They're 8.5" rims with a 35mm offset. L 40P15 and 40P10 R. The book says "The Turbo's wider rears are 245/45ZR16, except in Japan where, for some accountable reason, domestic manufacturers are not allowed to fit 45-profile tyres."

Over here, "everyone says" that Jspec owners should swop their 225 rears for 245 UK rears as this is supposed to give better grip. Well, I did but found no discernable difference in handling. I did find that the choice of tires in this size was extremely limited compared to the 225/50 and also the 245/45s were significantly more expensive. So on my Silver TT I changed back and on my Blue NA, I shall stick with the 7.5"s as Mr Nissan intended. I posted results on the forum here and the only other person who bothered to measure the tread found the same as me. 245s DON'T have more tread on the road then 225s. Why not? Dunno - I wrote to Bridgestone with pics but they didn't reply so sod'em.

both tyres together
Tyre A = 225/50 = Jspec rear
Tyre B = 245/45 = UK rear

The 225 is 218mm wide at the sidewall and has wear-to-wear tread of 199mm. The 245 is 221mm wide at the sidewall and has wear-to-wear tread of 197mm. Both are Bridgestone S-03s.The theoretically 20mm wider tyre is in reality 2mm narrower!

Also, according to Protyre, the J spec profile of 50 should give you a marginally smoother ride as this is not quite so low profile as the UK 45.

Now, given the 245 tyre has no more tread than the 225, has a slightly harsher ride and costs £30 more, tell me again why I should want to get rid of my J spec rears and replace them with UKs?

From the evidence so far, it seems that J spec owners can stop worrying about having 225s all round - there's no tread difference, you get a slightly better ride (I can't tell the difference but that's the theory) and they're cheaper.

If you look down the side of the car, J wheels (and UK front) look vaguely dished outwards and UK rear look dished inwards.