Here's a wheel conundrum.

 

"Everyone says" you should replace the J spec rears with UK spec rears.

Both are 16". J spec are 7.5" wide and take a 225/50. UK are 8.5" wide and take a 245/45.

 

The UK wheel is 1" wider than the J spec. The UK tyre should be 20mm wider (0.78").

 

That's the theory!

 

In this picture, there is a UK wheel/tyre and a J spec wheel/tyre. Can you tell the difference?

No, neither could I and neither could the guys at Protyre.

 

So I took some close-ups:

 

Tyre A is 221mm wide at the sidewall and has wear-to-wear tread of 197mm

 

Tyre B is 218mm wide at the sidewall and has wear-to-wear tread of 199mm

 

Which one is the 225 and which the 245? Both are Bridgestone S-03s.

 

Actually Tyre A is 245 and Tyre B is 225. Which means 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.

 

Any tyre gurus here who know any different? Be interested to hear...

 

Cheers - Gio

The fitting of wider rear rims could be to do with steering response and not grip. If you place a wider rim on a vehicle it will give sharper steering response when compared to a thinner rim using the same tyre. As the UK tt has rear wheel steer it might be this (and tight UK road bends?) that caused the guys at Nissan to spec a wider rim. The increase in tyre width is a by product...

 

...just my 2ps worth...

Coming into this discussion late, I know... but I've been a busy boy.

 

Tyres aren't very important standing still or running at constant speed, which is what they do most of their lives (and maybe where most of the wear comes from?) You notice the differences on hard starts and stops and on cornering. When the weight isn't through the centre of the contact patch - ie when you are doing any of those things - it's probably a whole different discussion.

 

For instance, wider tires give you better cornering (usually) but are (often) WORSE in the wet. So it's all a bit more complicated than looking at wear patterns on an unladen tyre...

Urghhh :D

 

It's an old topic but I thought I'd add something.

 

In Ray Hutton 300zx enthusiast companion book he tells that, 'The turbo's wider rears are 245/45zr16, except in Japan where, for some unaccountable reason, domestic manufacturers are not allowed to fit 45-profile tyres.'

 

Therefore they probably had to fit the 225 tyres out back cause 245/50 would have affected the drive ratio to much. :nelson:

 

Cheerz.

Get rid and buy some decent alloys :D

sorry to go slightly off topic but I have a spair set of UK front wheels that I would like to put on the rear to allow me to refurb the uk rear alloys, is this OK?

Cheers

Ady

Also slightly of topic , I think the standard front wheels on the Zed look naff because their an inch less wide than the rears and their set too far into the wheel arches.

Anyone else agree ?

What i propose to do is get hold of a pair of rear wheels and put them on the front.

Is this advisable ?

Cant forsee any problems apart from rubbing inner wheel arch on full lock.

I think this would make the car look miles better.

I am currently also looking for a set of Skyline R32 (GTR) alloys i may put on instead , as these are 8jX16 allround and i can fit my Zed tyres on them. They look pretty cool too (i think). Seen one recently with a set on in the Autotrader.

back to what SHUNTER posted

if the car needs an sva test whan landing, then most jap tyres won't pass

unless they have "the little squiggle in a small circle" it looks like a lightening flash, and GENERALLY jap tyres have a lower speed rating than uk tyres

BUT a lot of imports are now coming with euro spec tyres

 

ive just swopped a set from a pajero for the sva, and straight back after, speed is hardly an issue for a pajero lol