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17x8 front - 17x9 rear wheel offset help please
Posted: Thu Nov 03, 2022 11:00 am
by V8turd
Can anyone help regarding offsets for 17 inch wheels please ?
Currently run 16x8 front and 16x9 rear but I'm looking to upgrade the brakes to either 540 calipers or e38 Brembo 4 pots with 312mm discs and I want 17 inch wheels to guarantee clearance
What offset should I buy for 17x8 front and 17x9 rear please?
Rear arches are already rolled, front wing lips can be rolled no problem.
Car is on bc coilovers but not dropped on its arse (I don't like that look now I'm north of 40
lol.
I don't want poke, more flush fitment.
If anyone could help before I click buy om wheels I'd be eternally grateful
Thanks
Re: 17x8 front - 17x9 rear wheel offset help please
Posted: Thu Nov 03, 2022 12:17 pm
by flybynite
Difficult one to answer without getting a tape on the car.
Going from 16" to 17" won't have any effect on offset (other than you can run a bit more width as the wheel is higher up a sloping front strut.
The problem you will have with 4-pot calipers is clarance from the back of the spokes which is nothing to do with the mounting surface that 'offset' measures.
You can get 2 wheels with identical size and offset, one will fit 4-pot one will not due to the design of the back face of the wheel 'spokes'
If you want to get 7x9 in there (depending on the tyre) you are not going to have much wiggle room. You will be better getting a higher offset (around ET40 to ET50) then you can use a spacer of the exact size to push the whole wheel out to clear the caliper and get the required placement.
Re: 17x8 front - 17x9 rear wheel offset help please
Posted: Thu Nov 03, 2022 12:46 pm
by V8turd
flybynite wrote: ↑Thu Nov 03, 2022 12:17 pm
Difficult one to answer without getting a tape on the car.
Going from 16" to 17" won't have any effect on offset (other than you can run a bit more width as the wheel is higher up a sloping front strut.
The problem you will have with 4-pot calipers is clarance from the back of the spokes which is nothing to do with the mounting surface that 'offset' measures.
You can get 2 wheels with identical size and offset, one will fit 4-pot one will not due to the design of the back face of the wheel 'spokes'
If you want to get 7x9 in there (depending on the tyre) you are not going to have much wiggle room. You will be better getting a higher offset (around ET40 to ET50) then you can use a spacer of the exact size to push the whole wheel out to clear the caliper and get the required placement.
I've measured the current wheels to be an et10 16x8 upfront. I have to run a 5mm spacer to clear the rx7 calipers and it's still rizzla tight there.
(Previous owner fitted the wheels and brakes so I'm not guilty there lol)
Am sure the rears are 16x9 et10
So even if I up size to 17s, the offset stays the same if I want the same look?
I'd probably be better with an et10 and a 10mm hubcentric spacers on the fronts and run the backs as 17x9 et10 ?
Offsets confuse me although I get the basics (kind of)
Re: 17x8 front - 17x9 rear wheel offset help please
Posted: Thu Nov 03, 2022 1:35 pm
by flybynite
Just get on willtheyfit.com and have a play
My gut feeling is at ET10 you will have too much dish. if you space out to clear the calipers you will poke the rim out too far.
Like I say it will come down to spoke design as to how much clearance you get on the calipers ET will tell you nothing
Re: 17x8 front - 17x9 rear wheel offset help please
Posted: Thu Nov 03, 2022 3:39 pm
by V8turd
Cheers mate for the link. I've been playing on there and have some results and now know what to get
Thanks a lot that's helped loads