FlyinTomato

previous owner installed 10 54ET with 7mm spacer running 285 30 18 toyo t1r on the rear. This set up seem to be spot on. clears the oil line without problem.

But the wheels were bent, and unfortunately damaged recently.

I have since bought a set of fikse fm10 with 10.5et57, and looking to run the 285 tires off the old wheels. I was under the impression that they would clear too with correct spacers.

based on the offset calculator, with a 15mm spacer, i am looking at 1mm less inner clearance and poke out 11mm compare to 10 54et with 7mm spacers.

the new fronts are 18x8 +51. I believe they will fit okay.

car is 1992 c2

Any suggestion on fitting these wheels?

sml

make it easier and ignore (mostly) irrelevant info ie the diameter.

here is 8ET50 ... yours is 1mm further inwards ... so this is a pretty close example ...
https://rennlist.com/forums/964-foru...ighlight=8ET50

summarising the rear ..

previous owner = 10ET47 = OK

here is my 10ET40 which is a harder more aggressive fit ... https://rennlist.com/forums/964-foru...ghlight=10ET40

you are proposing 10.5ET42 .. you are familiar with the offset calculator .. you can use your existing fitment to measure clearances .. you have all the info you need .. just remember to take into account any changes with ride height, camber, spring rates etc.

FlyinTomato

so, my situation, the new 10.5 wheel will use 285 tires , aiming with the new effective 42 offset. (1mm less inner, 11mm more poke) it will clear the oil line. there is plenty of room. 8mm there i suppose.
now the poke, the tire isn't getting larger. the position is relatively the same. will the 1/2 inch wider wheel change the shape of the tire? cause rubbing?

the car will be lowered, will try to get -2.5 camber. the new wheel spec is 10.5 +57. So I will have options with spacers. which is better?
13mm spacer, 3mm less inner, EXTEND an extra 9mm outer
15mm spacer, 1mm less inner, Extend an extra 11mm outer.

here is the pictures of the old 10 et54 + 7mm spacer with 285 30 18 T1r Tire, it clears the oil line, and no rubbing. with stock suspension. car on the ground. with -1.5 rear camber

c didy

Gonna be close. Probably need to try it to find out. Each car is a little different.

sml

if you from -1.5 to -2.5, my guess is that you will lose about 5mm of clearance.

so 10ET47 with 285 = 8mm of inner clearance as you stated:
less 3mm less inner clearance with 10.5ET44 285 (as you calculated)
less 5mm less inner clearance with camber from -1.5 to -2.5 (as I guessed).
result = clearance = 0mm.

so i think it would be pretty much touching the oil pipe .. i would go for the 15mm spacer .. possibly more.

also do the comparison calcs of 10.5ET44 vs 10ET40 and you check all the clearances which I stated in the thread .. although I had 265 tyres but might be worthwhile.

FlyinTomato

@SML, knowing that 47mm offset was spot on. why did you choose to use 40?
I ordered 15mm spacers. Let's see how they fit when spacers come in. do not want to massage the fender, if all fail to fit. I will probably have fikse to rebuild them to 10in, possibly 9.5. I can't stand rubbing.

sml

because i only had two sizes choices in the OZ Alleggerita wheels ... there was a recommended 9" or 9.5" option (cannot remember which one) but I wanted to go more aggresssive and I thought I could fit in the 10ET40 .. which I was really happy with in the end. When you need to roll the fender 3 or 4mm, you can go for a super-tight fit ... particularly with very stiff springs

FlyinTomato

Can you tell me more about the rolling process? I understand most do not recommend rolling the steel arch.

I've rolled the fender on my old car using fender roller and heat gun. But the lip was much large than the 3-4mm lip on the porsche. so it wasn't too bad. end result was good too.

this is a none reversible step. Have to take it with caution

My suspension set up will be bilstein with turbo red springs.

sml

You will be able to see the 4mm lip on the inside of the fender. you can fold this over flat but the downside is:
(a) can cause paint to crack .. I had a few 0.5" cracks
(b) the arch may lose 2% of stiffness as the right-angle lip stops a bit of flex (nothing really but only added as i'm sure someone would mention otherwise)

Or if the lip is not enough (maybe you can get 2 or 3mm clearance) you can flare the fender a bit .. worked easily enough.

FlyinTomato

Bought these 15mm spacers from a forum member. How do I even fit these? The open lug nuts arent sitting flush on the hole where the stock studs goes into.

Vandit

Any idea what the origin of those spacers is? Are they from VertexAuto?

Read through my experience w/ 15mm bolt-on spacers from VertexAuto
https://rennlist.com/forums/964-foru...ment-help.html

I sent Vertex an email and a link to ^that thread^ and told them I wasn't happy with them and they asked me to "describe the problems" as if I hadn't already written them all out in the thread.

They're still sitting on a bench in my garage.

FlyinTomato

my fm10 nightmare continues... I am getting very annoyed. about to sell these wheels!

original spacers are from HR. Without the new studs. They are just spacers. should've done more research. more money wasted I guess.

I think these Vertex spacers only works with oem wheels that have the "pockets". see example below

FlyinTomato

Sorry to hear about your experience. I don't know what to do with these spacers now. They are my official paper weights now...

Bill Verburg

yes a wider wheel stretches the tire cross section, rule of thumb is .2" tire more cross section per .5" of wheel, the tread width does not change but the sidewall shape does.

for the wheels, 10 ET 47 to 10.5 ET42 places the outer face of the wheel 11.35mm more outboard and the inner face 1.35mm more inboard.

not counting the additional stretch due to the wider wheel, the tire sidewalls follow the wheel face, add the stretch and the sidewalls are ~.1" more on each side.

FlyinTomato

Bill, very very helpful info. Thanks

I've contacted fikse to have them rebuild the rear. waiting to hear from them.