I ordered Axis HIRO rims from North East Auto Design about a month ago. When I ordered, I asked them what the offset would be, and they said they didn't know yet because they haven't arrived in the country yet, and they need to fit them on a Z. They assured me that they would get me an offset that fits well. I called today and asked if they knew what the offsets would be yet. The person I spoke to said for the track Z with the brembos it would be around 20 in the back and 15 in the front, and for the non track models it would be 40 in the rear and 35 in the front.

40/35 seems very high to me, and I mentioned that. He said that offset depends on the wheel....you can't compare offsets on different wheels. So here's my question; it doesn't make sense to me why I wouldn't use the same offsets as the track model with brembos?? Position of the wheel hub is in the same place right? What if I want to go with aftermarket brakes at some point? Something about this just doesn't sit right to me, but i'm not a wheel expert by any stretch.

Anyway, I would REALLY appreciate it if one of the resident wheel experts could tell me if what they've told me makes sense. I don't want to end up with the wheels being tucked in too far and looking odd.

thanks

 

btw they are 19" rims.

 

well... the 20 and 15 offsets will make the wheel stick out to the fender, the 40 and 35 will sit in more. The 15/20 combination certainly is aggresive, depending on the width you may even be outside the fender.

And, offset is always measured the same on every wheel... all wheels with a ET35 (offset of 35mm) are the same offset. What they told you makes no sense at all. If you are looking at the wheel from the side, the offset is the measurement from the rear surface of the mounting hub to the centerline of the wheel. Tirerack have a good picture http://www.tirerack.com/wheels/tech/offset.htm

Offset is good to consider when trying to clear Brembos or other BBKs only becuase of its function of pushing the wheels out or tucking them in.

But the other consideration is the backspacing. The spokes may be inset or curved to far inward and will rub on the caliper, even if the offset is low... like 15 or 20. Have the retailer confirm there is enough space to fit larger brakes.

Hope that helps,

PeteH

 

Peter thanks for the good info. What you said makes alot of sense. So even with a width of 9.5" in the rear, is it your opinion that 40 offset would be too much (tucked in too far) ?

I want something that sticks out slightly more than my stock 18"s without hitting the fender. It sounds like there must be a 'perfect' offset for each X" width wheel on the Z....??

 

Stock wheels are offset 30. So 40 seems way too "set in the wheel well" for me. Look for offsets in the 19-27 range. Also keep in mind that most wheel manufactures well have maybe 3 or 4 different offsets per wheel size. You don't have unlimited choices, so you have to choose the best of the bunch.

 

the offset is relative not only to the width but wheel style as well..some wheels necessitate higher or lower depending on the spoke design.

 

What they did say is true, if they are strictly talking about the wheel in relation to caliper clearance. For certain wheels a 30 offset will not clear the front caliper on Brembo equiped cars. Rims that have a concave center that is aggressive or spokes that are set really far in the wheel (in from the outer lip) Other rims that spider out or are flush with the outer lip such as those 6 spoke Enkeis (forget the name right now) that a lot of ppl are running for winter can be used with a 30 or I have even heard that a 35 fits no prob.


So in a nutshell if they are referring strictly about offset in its relation to Caliper Clearance then they could be right in that all wheels are different and in the same size (eg 19x8.5) with same offset may or may not clear the calipers in teh same way. The design of the spokes are very important.

 

glad I could help.... I would think the ET40 would be inset into the wheel well more than what you are anticipating. A 22 or 25 ET on the rear with a 9.5" wheel will fill the wheel well more... so maybe try to stay in that range.

Cheers,

PeteH