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Wheel offsets and all that!


TV8

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I gave my new car it's first wash today and was a bit surprised by the concave (rear) and convex (front) wheels! I have only ever looked at a handful of cars and then I have been looking at the wheel rims for scuffs and the age of the tyres, rather than fundamentals...

Basically, at a glance, the wheels look identical but on inspection, they are not! 

Are the from and backs meant to be different? 

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Thanks. I wasn't sure as I was about to buy some Boxster s alloys and they look the same! I need to read up I think. 

 

Its a a shame I can't up load the pictures, it's got to be at least 15mm difference! 

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By way of example I have 7" fronts and 9" rears both with a 55ET offset. Just as you describe the fronts are convex and the  rears concave and, yes, perhaps a 15mm difference. So don't do a front to rear wheel swap to equalise tyre wear!

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Are you referring the Spoke pattern? 

I'm confused by this, as of course there is a staggering of the front and rear wheels. This means I have a shallow dish front and a deeper dish rear.But the spokes are all convex ( Bow outwards. )

Have I missed the point? 

 

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Perhaps it varies depending upon the wheel design?  I have 17" Sport Classic design wheels. Google images of these wheels wheels and you'll see the built in stagger.

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I need to sort out a photo account! This shows what I mean with the differences, so looks perfectly normal.

https://goo.gl/images/bpBphI

The reason for asking I have seen some larger/different wheels for sale from a Boxster s and now wondering if they will fit and work ok or perhaps I am just over thinking it!

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Those are indeed ike my wheels. IMO they suit the car well. 

In theory there is no reason why different style wheels wouldn't be suitable provided the diameter, width and ET value works. 

Post the proposed wheels widths and ET valurs and someone should be able to confirm they'll fit.

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Generally speaking. A lower offset will allow for more dish, spoke concave and push the wheel mounting outwards overall.

On stock factory wheels, this is often compensated by a slight variation in the spoke design/angle so to not add an aftermarket deep dish or hefty concave like some aftermarket wheels (or think bmw alpina wheel from an old 7 series).

Most rear wheel drive cars will have a wider rear wheel with a higher offset to keep it inside the arch legally. Most front wheel drive cars just seem to run the same size all round (until recent years where r&d and fashions have changed).

post up your size/width/offset with potential tyre sizes and I/we will try and advise. 

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5 hours ago, TV8 said:

I need to sort out a photo account! This shows what I mean with the differences, so looks perfectly normal.

https://goo.gl/images/bpBphI

The reason for asking I have seen some larger/different wheels for sale from a Boxster s and now wondering if they will fit and work ok or perhaps I am just over thinking it!

Those wheels are from a 986 rather than a 987.  I'm not sure they would look right on your car.  You currently have the 17" Boxster wheels, and the usual upgrade is to the 18" Boxster S wheels - sometimes referred to as Crab Claws.  

s-l500.jpg

 

Or Cayman S alloys
s-l1600.jpg

 

I would recommend going no bigger, but if you do want 19s then there's Carrera S (known as Lobster Claws)
 

s-l500.jpg

Carrera Sports
s-l1600.jpg

Or Carrera Classics
s-l1600.jpg

There are a few others, but if I were you I'd try to find a picture of a car in your colour with the wheels you like before going any further.

And don't overpay!  I've just bought a set of 17" Gen2 wheels for £103 and another £80 for a pair of rear tyres.  The 18" Gen2 Boxster S wheels on my car were £350 with good tyres (apart from a puncture) and the 19" wheels are sitting in the garage as the ride is too harsh on all but the smoothest of roads.

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2 minutes ago, Jason986S said:

I think the 19" crabs look brilliant on a 987, but the Carrera sports have to be my favourite. 18/19 has to go down to personal preference of appearance and what you can live with as a firm ride.

I love my Carrera S but I'm with you on the Carrera Sports, fantastic looking wheels.

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Thanks everyone, especially @Araf those pics and guidance on price is very useful. 

The wheels in the picture I linked are not what I have or what I am thinking about but they showed the cave/vex profile! 

The ones I am thinking about are the crab claws.

However, this being "our car".... I have consulted with management on the options available and the either of the Carrera ones are favoured. The crab claws got the big thumbs down!

 

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6 minutes ago, TV8 said:

Thanks everyone, especially @Araf those pics and guidance on price is very useful. 

The wheels in the picture I linked are not what I have or what I am thinking about but they showed the cave/vex profile! 

The ones I am thinking about are the crab claws.

However, this being "our car".... I have consulted with management on the options available and the either of the Carrera ones are favoured. The crab claws got the big thumbs down!

 

Good choice :thumbsup_anim:

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Brace yourself then.  Carrera Sports are rare as hen's teeth and about £2k a set.  I had them on #3 and they really are the dogs.  GT Silver spokes and polished rims. B) 

The Carrera Classics (5 spoke) are available in 18" for the 986.

s-l1600.jpg

Most of the wheels are made in Boxster and 911 fitments.  The fronts are interchangeable but the rear 911 alloys are wider and have the wrong offset (though it can be corrected with 20mm or so of spacer.  You'd have to factor this in, if you went for 911 wheels.

 

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5 hours ago, Patt said:

Another thing to factor in.  ;-)

My problem is that I don't sell - keeping them on the basis that they 'will come in handy one day' :blush2: 

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On 25/01/2017 at 9:05 PM, Boxob said:

Very good deal @Jason986S. Right place, right time and therefore right price!

@Araf also seems to find the wheel bargains!

I just ask randomly and sometimes get lucky. They were from a breaker who had his personal car in the background, so I asked and I got. 

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18 hours ago, Araf said:

My problem is that I don't sell - keeping them on the basis that they 'will come in handy one day' :blush2: 

Ditto, although my shed is getting a bit full now and I have a new kitchen to pay for and need some more door handles made for the house....why hasn't carbon come down further in price?  Thus I'm starting to get the inclination to ebay some stuff.

I really don't need three sets of skis or 3 AV amps..It's spring clean time :-D

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