600RR

Never too old to learn, but I'm hopeful it will happen someday. I don't understand. I have 8.5" ET50 on my front and 10.5" ET60 on my rear. The ebay wheels are ET50 front, and ET42 in back, but with 15mm spacers in back, why wouldn't they fit a NB? (the difference between 57mm and 60mm would seem to be sorta trivial. What's missing?

911Dave

ET60 means that the hub mating surface on the wheel is 60mm towards the outside of the wheel (the pretty side). ET42 is much more centered. So, if you try to put an ET42 on a car designed for ET60, your wheel will stick out 18mm too far. It's the opposite of what you're thinking.

So, it is possible to mount a NB wheel (ET60) on a widebody car (ET42) with a spacer, but you can't do it the other way around.

The foregoing example refers to the rear wheels.

speedy88

Think of it this way. ET60 in where the face of your wheel lines up with the edge of your fender. If you add more spacers to it, then it will stick out.

The lower the ET, the closer you get to the fenders' well. So, the WB can fit an approx. 39-46mm offset (ET). Add spacer to an ET60 will reduce the offset, therefore fitting WB cars.

Obviously I have too much time on my hands... :-)
Here is a diagram of the two wheels. See how you can put an offset 60 on a WB car using spacers AND why you CANNOT put an offset 42 wheel on a NB car?
__________________________
NB WHEEL

------|
>>| center of wheel/hub
------|

offset 60

________________
WB WHEEL

------|
>| center of wheel/hub
------|

offset 42

___________________________
Now, I hope you are more confuse than ever! ;-)

600RR

Dave: Thanks for the explanation. Makes sense,
Red: Thanks for the diagram. Helps a lot.

The pisser is that I was too lazy to check my bookmarks, but not too lazy to post a couple of meaningless pix. So much for recollection. Here is what I would have seen if I had checked first
http://www.1010tires.com/wheeloffsetcalculator.asp

Thanks again for the clearly much needed help. Appreciate it.

Gerry Kokoszka

I don't mean to hijack this thread but I have 2 ET50 black front wheels that I would consider selling if that will help anybody.

Kika

A picture would help considerably. and it is RL policy if you are selling something, to include the price.

You probably will reach a broader audience with a new thread.