Track wheels off my 1M, KOYA 18 X 9.5

[Steve Brown]

4 hardly used Koya "race wheels" 18 X 9.5, 5 X 120 pcd, 15mm offset. Fitted with well used Hankook 275/35 zr18 C41 slicks with about 50 laps left in them. Wheels previously fitted to BMW 1M but will fit most BMW's (135i, M3 etc) and other makes that use 5 X 120 bolt holes (some Hondas). $750

[135]

Unfortunately, they won't fit a 135i - an ET15 offset is w-a-y too low - they'd stick out 1"-2" beyond the guard, even with camber plates adjusted to the maximum. A 135i generally needs around 8"-9" wide ET38-45 front and 9"-9.5" wide ET45-60 rear. Otherwise I would have bought them. It's a shame we're so limited on offsets.
There might be the rare 135i that has had a 1M front and rear conversion done - @Curare86 is out your way. You could also advertise them in the Australia regional forum on m3post.
GLWS!

[Steve Brown]

Hi, I understand all you have said as I was not only the first owner of a 135i in Australia but also the first 1M owner. I'm a mechanical engineer of 48 years standing so trust my own judgement on most matters mechanical. The Koya wheels are the same weight as the standard 1M wheels (pretty much) and do have lots of hub thickness (135mm) so a few moments on a milling machine or borer could sort the offset out if you have a mind too. Smaller tyres can be fitted on these rims down to the sizes you mention so that should be OK too. There are also an awful lot of 135i owners driving around with their tyres sticking out outside the arches (which is illegal) but I guess they take the risk on themselves. The Koyas were a nice inexpensive way of getting some slicks on the car and getting it on a track. It is an experience I suggest every 1M and 135i owner needs to have before they die and if they don't it's a waste of amazing vehicles.

[koastal]

Pretty rare for an engineer to be wrong about anything.
From an engineering point of view, would the wheel be safe after having approx 30mm of material removed from it ?

Honda PCDs are typically 114.3
Most Holdens are 120 though- dif center bore though

I would love to see a 135 with et: 9.5 inch fronts

Def best advertised on the M3 forum though.

[135]

I just realised that they were 9.5" square so I jumped the gun a little there. I wouldn't have a chance of fitting those on the front and I've measured - a lot. I was blindsided by the great price!
Like you, I don't subscribe to the idea of wheel/tyre poke - I think the tyre's sectional width should be slightly wider that the wheel. Each to their own I guess.
Machining the hubs is a good option though - that was one idea that I was thinking of too.
btw, are those Z214 semis a C51 compound?

[Steve Brown]

Yes the tyres are c51 and machining 30mm from the width of the hub portion of the wheel is not an issue from a strength perspective. However, the bolt holes are drilled to a depth that allows standard wheel bolts to be used so there is only about 5mm that can sensibly be removed from the inner hub face. In saying all that, these wheels aren't going to suit the 135i without a lot of fiddling by someone who knows what they're doing so I'll take this post down shortly.

[koastal]

Originally Posted by Steve Brown

Yes the tyres are c51
.

Your original post says C41 compound

Engineers cant be wrong twice in a row surely

[Steve Brown]

C51 it is. You must be a lawyer eh?

[koastal]

Originally Posted by Steve Brown

C51 it is. You must be a lawyer eh?

Nope - completed year 10 though and own the 3135 th 135i sold (i think)

Would you separate the tyres ?