FV Radial wheels_tires Tech

In order to stop "robbing" Brian's thread about inclusion of the radial tire for SCCA events, which has drifted a bit :), I will post the data here...

There are now multiple wheels available that are allowed in Challenge Cup and Driverz Cup, all with the same basic 5.5" width x 15" diameter, backspacing and weight at just above minimum.

There are two different wheel lug seats, 1) the original VW ball seat (a radiused surface) and 2) a 60 degree cone seat.
It is important not to mix the two. Damage to the wheel will occur and the wheel will loosen. In particular, if you switch back and forth between original VW style wheels for slicks and the new wheel for radials, be sure you use the right lug nuts...

I purchased Mobelwagen wheels for the radials. They definitely have a ball seat. I already have studs installed in my drums and ball lug nuts. However I am changing from drums to discs so will need new studs.

What I find is the following:

My current studs are a standard 38mm total length, which leave approximately 1.1" sticking up above the surface of the drum.
The picture shows the rear drum mounted to a Mobelwagen wheel and the ball lug nuts are just flush with the stud, a bit short IMO.
The ball lug nuts I have are approximately 0.83 height, and are actually a Honda lug nut (12mm x 1.5), but I believe this is pretty close to standard for the 12x1.5.

Due to the thickness of the Mobelwagen flange, what works for the VW wheel is just short for the thicker flange. Looking at the two pictures included you will see the measure from the back side of each wheel (the contact to the drum face) to the top of the lug nut is approximately 0.2" longer on the Mobelwagen wheel. As a note, because the ball lug nut will wobble I placed a 3/16 plate on top to get my measurements so the numbers shown include that plate. It's the difference that matters.

45mm studs are commonly available that will be perfect for the Mobelwagen. Empi does have another stud even longer available should someone have a different wheel that is even thicker.

None of these measurements apply to the cone seat wheels.

https://www.apexspeed.com/forums/att...d=114138&stc=1

https://www.apexspeed.com/forums/att...d=114139&stc=1

https://www.apexspeed.com/forums/att...d=114140&stc=1

Barry,
Are you SURE your Mobelwagen's are BALL SEAT? All of the info I saw on the internet .. various vendors SAID they were BS.. but the wheels *I* received.. a couple weeks before you bought yours, were definitely ACORN 60 degree mounting setup.

Apparently, the early versions were BS and the later versions were Acorn.... maybe?
Just a note for all to BE CERTAIN which you have before installing your wheels. I assumed that 'early' meant 'some time before then (whenever 'then' might be)' and all subsequent would be Acorn .. but if yours are really BS, that info is OUT THE WINDOW.
Steve, FV80

Steve,

Yes, it's clear just based on feel, but I checked further by putting a straightedge in the seat. There is a pronounced curvature/radius to the seat. A cone type seat (also called "acorn") would be flush against the straightedge.

I can't say what others might get. The CIP1 wheel states it's a typical 60 degree cone, so I'm guessing you have that version. As to manufacturer, maybe there is more than one, but my limited research suggests they are coming from the same factory with changes to suit individual vendors. Mobelwagen doesn't produce the wheel, they just provide their spec. I see some folks claiming the wheels are made by Maxilite. And I would bet every Maxilite wheel is produced in China.

Anyway, mine is a ball seat, I'm sure. But there are certainly other types, and other wheels from Mobelwagen are stated as conical seat including 4 lug VW wheels. That may be the confusion.

Perhaps, Mobelwagen has BOTH? Regardless.. everyone BE SURE of what you have BEFORE racing on them (with appropriate lug bolts/nuts).
Steve

Steve, they certainly have wheels with ball and wheels with cone. But their only listing for this type of wheel is for ball seat.

If I am correct in my belief, and the wheels are all being made in the same factory, then it's quite possible for the same wheel to get the wrong seat machined. In other words, maybe Mobelwagen received some wheels that were machined for cones and sent them out to customers without knowing they were wrong. It's not all that clear to the naked eye. And while the quality of the casting looks excellent to me, anyone can make a mistake and the Chinese manufacturers seem to be on the wrong side of that fairly often in my experience.

Steve is quite correct to make sure everyone is cautious in using the correct lug nuts for the seats you have. Disaster is in the making if you use the wrong ones.

Edit to add - Maybe Mobelwagen provided cone seat in an earlier version? I don't know but I will ask them and report back.