Hub centric question

[Zagato78]

The Lancia Beta wheels are hub centric. I don't understand the reason for this. As we consider wheel options for the Rally car, is the hub centric nature of the wheels necessary?

What does the hub centricity add to the overall wheel stability? If the hub centric is not required, then other wheel and rotor options become available.

Look forward to your thoughts.

Dan

[sickchilly]

Think about it, Dan. What centers the wheels on the hub if the wheels aren't hub centric? The bolts with their conical seats. That's it... those fine pitch alloy bolts are relatively soft. Do you want your ralley car, which is going to accept some abuse no?, to rely on only the bolts to keep the wheel on the hub axially and radially?

For the most part, hub centric wheels are not required, but FIAT/Lancia and numorous other manufacturers must've done it for a reason. I'd maintain when ever possible.

However, I've always found it odd that on the FIAT 124 Spider, the front wheels are hub centric, but the rears are not! :)

[Zagato78]

Trent, you touched on exactly why i'm questioning it. I do agree that the relying only on a soft bolt would be a concern.

But then again, why would the 124's not be? They were used in competition as well, if not more so. Are other Fiat cars also hub centric?

The later Fiat 124's (refering to the 84/85) use the Beta rotor. So they did eventually adopt the hub centric rotors to those lines. Maybe corner weight or total power to weight were the concern.

Either way, just exploring options. I wonder if the wheels were a stud rather than bolt set up would the concern be the same?

Dan

[Allen Lofland]

Guys: I think you will find that the 124 spider is hub centric on the fronts and also on the rears of the later cars :)?????
But think about it, the fronts are the real workers, They need to be centric ,,,IMOP
When I went shopping for the Scorpion whells I inseisted on hub centric and found them easily.

[SubGothius]

The later Fiat 124's (refering to the 84/85) use the Beta rotor.FWIW, did we ever conclusively settle that the later Pinin spiders used Beta rotors? I recall offering that conjecture as a possibility, but I don't recall that it was ever confirmed...

Also, I might speculate that the FIATs' fronts were hub-centric while the rears were not, probably somehow related to steering forces vs. driven-wheel forces...?

[Gregory Smith]

The hub-centric design prevents the wheel being forced off-axis from road flaws, etc. The bolts or nuts simply clamp the wheel to the hub, while the hub-centric ring keeps it centered, also good for drums. Using the hub-centric design, only on the front at least, prevents the slight imperfections from non-hub centric designs from being felt in the steering wheel as wheel-hop, etc. Bolts and nuts/studs work better in tension than they do in shear.

A non-hub-centric drum will feel out-of-round at the brake pedal, but a rotor won't, very weird when you encounter it. I had this problem on an 850 when a vendor supplied the wrong drums.

[Zagato78]

Good info guys, thank you. We'll be sticking as close to original layout as performance pieces allow

thanks again

Dan