GR86 What offset do I go for?
- Thread starter Mattmpm
- Start date
It depends on what you're trying to achieve or what wheels you're looking at.
The stock set up performs well on track and road already.
Purely from the aesthetics perspective, the stock wheels work well with 20mm spacers to fill in the gaps between the wheels and arches (well documented on other GR86 forums).
A similar poke could be achieved by choosing 18/8J with a 35+ offset and 225/40 tyres, as seen in this chart:
www.willtheyfit.com
The stock set up performs well on track and road already.
Purely from the aesthetics perspective, the stock wheels work well with 20mm spacers to fill in the gaps between the wheels and arches (well documented on other GR86 forums).
A similar poke could be achieved by choosing 18/8J with a 35+ offset and 225/40 tyres, as seen in this chart:
Alloy Wheel & Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit
Alloy Wheel & tyre fitment calculator - it calculates inset, poke, speedo error, tyre stretch and loads more.
www.willtheyfit.com
If you are going for 8J ET35 to 40 will be perfect.
For reference this is an 8j ET35 wheel on stock suspension
https://www.ft86club.com/forums/showpost.php?p=3494256&postcount=220
For reference this is an 8j ET35 wheel on stock suspension
https://www.ft86club.com/forums/showpost.php?p=3494256&postcount=220
- Thread starter
- #4
Perfect, an ET38 should be just right thenIt depends on what you're trying to achieve or what wheels you're looking at.
The stock set up performs well on track and road already.
Purely from the aesthetics perspective, the stock wheels work well with 20mm spacers to fill in the gaps between the wheels and arches (well documented on other GR86 forums).
A similar poke could be achieved by choosing 18/8J with a 35+ offset and 225/40 tyres, as seen in this chart:
View attachment 22478
Alloy Wheel & Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit
Alloy Wheel & tyre fitment calculator - it calculates inset, poke, speedo error, tyre stretch and loads more.
Lower et will add some brakesteer on cambers, curbstones and especially on rutted roads. If that applies to you depends on your driving, I personally would go for et42 thereabouts on 8J for looks and driving compromise (which I had on my gt86 iirc).
- Thread starter
- #7
Yes, looking at going for some coilovers too, with 1 deg negative camber
byebyeMX5
Totally Hooked
The Mathematics of wheels is a dark art to me and Im looking to purchase a set that is completely stock size and fitment which of course then takes the 215,40 18 tyre, not looking at spacers as happy with the way it all works now.
If I could be so bold as to ask would the below fitment be correct.
Oz Ultraleggara
Width 7.5 inch (Im thinking thats the J!!)
Diameter 18 inch (Thats the round bit!!)
PCD 5x100 (thats what makes the wheel nuts align with the threaded bits!!)
Offset 48. (I have no clue at all!!)
Many Thanks in anticipation of confirmation Im going to buy the right thing!!
byebyeMX5
Totally Hooked
The offset refers to how far away the middle bit of the alloy wheel is (the mounting surface where the bolts got through) from an imaginary centre line of the alloy wheel itself.
If you have a fairly large offset of ET48, like the GR86, then the mounting surface of the alloy is farther away from its centre line and is closer to the outside of the wheel - this means that you have to push the whole alloy wheel deeper inside of the car's wheel arch in order for it to mate with the wheel hub of the car.
If you reduce the ET offset, to say ET30, it means that the alloy wheel's mating surface is now 18mm closer to its imaginary centre line (48-30); so when you go to put the alloy wheel on the hub it won't go into the wheel arch as far and the alloy wheel will 'stick out' by 13mm more than the original wheel.
This is one reason you have to be careful when going for wider wheels and tyres; if the offset is also significantly less than the original fitment, the combination of changes can make the alloy wheel stick out from the wheel arch too far, making the car non-MOT compliant and therefore technically illegal (safety of people/pedestrians etc). It's why a lot of cars with super wide wheels have big flared arches - so the tyres don't stick out from under them and potentially drag objects/persons into them.
I have found an equally dull but, more expert, explanation at the Oponeo website HERE.
Jokurt
Devoted member
Hi,
I was eyeing with the ultraleggera too.
The wheel sizes on the oz configuator for the GR 86 are different to the ones you mentioned.
There are width 8inch and diameter 18 inch or width 7.5 inch and diameter 17 inch. But both ET48.
I don't know if there are country specific sizes, but maybe it is worth checking again.
the 8x18 works on our cars.
byebyeMX5
Totally Hooked
Hi Jokurt
Ive just been on the OZ configurator also and dont see the 7.5 inch option available on the 18 inch wheel.
I was using a UK supplier that through their configurator by Car it showed an exact match to stock size.
I will give them a call next week to confirm, Ive also found a reasonably local OZ stockist that has a showroom and go over to see them to check the colour.
And thank you for confirming the 8 inch will fit fine and Im guessing will put us on to a 225 tyre.
Im in no rush as Ive got CC2's on the stock rims and wont look to change them for another 8 or 9 weeks.
