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Whats the difference between fronts and rears? (wheels that is...)


johnnyboy

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I have tried to look this up in previous threads but cant find an explanation.

 

My Winter tyres are on a set of standard touring alloys (2007 350z) which appear to be identical but are stamped "front" and "rear".

 

They are all 18" diameter, 8" wide, 30et offset, JJ rim profile

 

(I always wondered what JJ meant - as against just J - but my searching this morning explained it :) ...)

 

I have always been careful to put the fronts on the front and the rears on the back, but every year it bugs me.

 

So what is the difference?

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If I remember correctly, the fronts have deep recess/cave/etc (5 in total) on the centre hub (inner side), whilst the rear has none or maybe just very shallow ones. This was my guess as the front wheels needs those recess/cave/etc so that the small lug(on disc brake) can go into those recess/cave/etc when you put your wheels on.

Edited by veeg33
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I know the answer to this however very difficult to explain clearly.

 

The difference is on the "inside" of the wheel which can only be seen when the tyre is removed.

 

I will get some images up later once I have been over at the shop.

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I know the answer to this however very difficult to explain clearly.

 

The difference is on the "inside" of the wheel which can only be seen when the tyre is removed.

 

I will get some images up later once I have been over at the shop.

 

 

I knew somebody would know!

 

(and I should have expected it to be you, Alex)

 

So what harm would it do to get it wrong?

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What do you mean by getting it wrong ?

 

The wheels are clearly marked front and rear :thumbs:

 

 

You obviously have a high regard for the intelligence and diligence of the 350z driver (ie. me) and my local tyrefitter. (and I wouldn't actually say its "clearly" marked... maybe you keep the inner side of your wheels cleaner than I do... I had to wire brush it to see which was which...j

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I have tried to look this up in previous threads but cant find an explanation.

 

My Winter tyres are on a set of standard touring alloys (2007 350z) which appear to be identical but are stamped "front" and "rear".

 

They are all 18" diameter, 8" wide, 30et offset, JJ rim profile

 

(I always wondered what JJ meant - as against just J - but my searching this morning explained it :) ...)

 

I have always been careful to put the fronts on the front and the rears on the back, but every year it bugs me.

 

So what is the difference?

 

I would be interested just how the front and rear differ, apart from the obvious marks and lug, as if they are both 18"x8" and 30 offset, and weight exactly the same,i really cant see any reason not to interchange them.

 

Oh! and JJ denotes the height and width, and shape of the rim flange that the tyre bead sits on,

JJ = 18.0mm high x 13.0mm wide, with a 13.0mm radius

J = 17.5mm high x 13.0mm wide, with a 9.0mm radius

Edited by Tricky-Ricky
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The the front wheels are 8 inches wide and the hub has a bolt/lug screwed into it (which can be removed) and prevents some of the rear wheels which are 8 and a half inches wide and won't fit on the front hub due to the bolt fitted as previously mentioned. The GT touring wheels (not the Rays)are; front 8 inches wide with 30mm offset and the rears are 8 and a half inches wide with 33mm offset. As Alex has previously mentioned they are marked to prevent incorrect fitment but if a previous owner has removed the bolt/lug from the front hub then both front and rear wheels will fit either hub. I hope this makes things a little clearer.

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Thanks but the OP was talking about std wheels of the exact same size, IE 8"x18" x 30 offset, hence my question.

Obviously if there is a size difference fitment would be common sense.

 

Exactly. all 4 wheels are the same size/specification as far as I can see (apart from the cast in "front" and " rear" on the back of the same spoke as the cast in Diameter, width and et).

 

And although I have not had it from new, it was a one owner car with 12,000 miles on it when I got it, with every indication that it had not been fiddled with in any way and with what I am pretty sure were OEM fitted wheels with half worn original tyres. (I then bought a set of Rays and use the originals for winter tyres...).

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If I remember correctly, the fronts have deep recess/cave/etc (5 in total) on the centre hub (inner side), whilst the rear has none or maybe just very shallow ones. This was my guess as the front wheels needs those recess/cave/etc so that the small lug(on disc brake) can go into those recess/cave/etc when you put your wheels on.

 

All four of mine, including the two stamped "rear", have the 5 recesses you describe. (I have been trying to post photographs but it has defeated me... and they are not very good photographs anyway...)

 

Looking at other posts, maybe it is the 8.5" rears that don't have the recesses?

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