X5M rear hub - best option 72.6mm-->74mm wheels?

[speedwaywhite]

I'm in the market for 20" wheels to replace my now-winter only 300M's. In looking at options, many of the wheel choices only are 74mm hub. Are there two options besides changing the hub in the rear to go from 72.6mm-->74mm?

1) Are there spacers (e.g., 20mm width) that convert the hub?
2) Anyone running, safely, Hub Centric Rings 74.1mm OD - 72.6mm ID?

Thanks for your experiences and insight.

(and yes, I'm very, very familiar with the search option!)

[upstate650]

You don't want to change your hub

I and many others use a ring alone or a spacer with a ring without issues. You can also get an adapter that will mate hubcentric to your hub and hubcentric to a larger bore wheel. I have one of those on order.

All perfectly acceptable ways to skin a cat. And any combination of them will result in a perfect ride.

[mitch808]

There is nothing wrong with a hub centric ring adapter. It's what they are made for, They (hubcentric rings) center the wheel on the hub, nothing more.

It doesn't hold any load at all. Thats what your lug nuts do to the face of your hub when torqued down properly.


I've bold'ed the important part of what I'm saying.

[rennis]

Originally Posted by mitch808

There is nothing wrong with a hub centric ring adapter. It's what they are made for, They (hubcentric rings) center the wheel on the hub, nothing more.

It doesn't hold any load at all. Thats what your lug nuts do to the face of your hub when torqued down properly.


I've bold'ed the important part of what I'm saying.

Wait what!? No no, the hub DOES bear some of the load. Which is why hub-centric spacers work, and non-hubcentric spacers or adapters are garbage.

I use or have used hub rings on nearly every vehicle I own - they work just fine to adapt a wheel's bore to a specific hub - and the small diameter in this situation allows for a very thin metal ring, which is ideal as well.

[dkreidel]

Originally Posted by speedwaywhite

I'm in the market for 20" wheels to replace my now-winter only 300M's. In looking at options, many of the wheel choices only are 74mm hub. Are there two options besides changing the hub in the rear to go from 72.6mm-->74mm?

1) Are there spacers (e.g., 20mm width) that convert the hub?
2) Anyone running, safely, Hub Centric Rings 74.1mm OD - 72.6mm ID?

Thanks for your experiences and insight.

(and yes, I'm very, very familiar with the search option!)

I'm using BBS's system that has oversize wheel hub bores and hubcentric rings with retainers. 20" BBS SV but are available in 22" also.

[mitch808]

Originally Posted by rennis

Wait what!? No no, the hub DOES bear some of the load. Which is why hub-centric spacers work, and non-hubcentric spacers or adapters are garbage.

I use or have used hub rings on nearly every vehicle I own - they work just fine to adapt a wheel's bore to a specific hub - and the small diameter in this situation allows for a very thin metal ring, which is ideal as well.

I'm referring to rings and not spacers.

[speedwaywhite]

All - thanks for the words of advice. I've never had to use a hubcentric ring adaptor, but it sounds like a perfectly viable option. Now to just find the perfect wheel...

[rennis]

Originally Posted by mitch808

I'm referring to rings and not spacers.

same concept - the rings adapt the wheel bore to the vehicle hub, same way as a hub centric spacer adapts.

You don't have to take my word for it. pop out those rings and bolt the wheels back up. You won't like the results.

[upstate650]

Originally Posted by rennis

same concept - the rings adapt the wheel bore to the vehicle hub, same way as a hub centric spacer adapts.

You don't have to take my word for it. pop out those rings and bolt the wheels back up. You won't like the results.

I think he meant that the ring is not weightbearing.

[mitch808]

Originally Posted by rennis

same concept - the rings adapt the wheel bore to the vehicle hub, same way as a hub centric spacer adapts.

You don't have to take my word for it. pop out those rings and bolt the wheels back up. You won't like the results.

Rings can be plastic or metal. Often some cheap chinese steel made from recycled childrens toys and computer parts.

Rings are not load bearing in any way. A proper torque sequence can center a wheel in many cases. And YES, I've run non-hub centric wheels before and they were fine, IF I adhered to proper star patterned torque sequence.

All load is on the wheel/hub face and studs.

If we're talking spacers that also offer some hub centric aligning features, then all load is based on wheel face/spacer/hub.

[rennis]

Did a bunch of reading on this and emailed some pals at a wheel distributor. One was in agreement with me at first...but then the debate started.

Looks like the hub pilot is not necessarily a weight-bearing surface as I was lead to believe, and as common sense might dictate.

Summary of that conversation:

It seems weird and against common sense but not long ago cars/trucks didn't use hub centric wheels. With car speeds increasing and the weight of suspension components dropping the ability to introduce vibrations into the chassis rose dramatically. Engineers found out that by centering the wheel along the spindle would greatly reduce the chance of vibrations. Being hub centric vs lug centric is merely a way to better center the wheel and reduce vibrations.

This is an example used on Semi trucks but the theory is the same.

http://www.conmet.com/products/hubs/faqs/

1. The pilots don’t look like they can support the axle load, why?

The purpose of the pilot bosses is to guide and align the drum and wheels at time of installation. For stud-piloted hubs, the wheel nuts are used to guide the wheels in place. Once the wheel nuts are torqued, the tire load (and braking load) is transmitted to the hub by friction through the mounting interface. The pilots take no load during service and only support the weight of the wheel and drum at installation

[mitch808]

You and I are not speaking the same language. Must be an east side vs west side thing?

Let's go back to the original question, and my statement.
2) Anyone running, safely, Hub Centric Rings 74.1mm OD - 72.6mm ID?

Yes "rings," are safe. They do nothing more than center the wheel on the hub. They hold no load. The actual act of tightening down the wheel secures it to the hub, and any all load is there between the wheel and hub face.

[rennis]

Originally Posted by mitch808

You and I are not speaking the same language. Must be an east side vs west side thing?

Let's go back to the original question, and my statement.
2) Anyone running, safely, Hub Centric Rings 74.1mm OD - 72.6mm ID?

Yes "rings," are safe. They do nothing more than center the wheel on the hub. They hold no load. The actual act of tightening down the wheel secures it to the hub, and any all load is there between the wheel and hub face.

I edited my post - I went back to my source on my information, and we pulled in some other people. In short, what he explained to me, and what I relayed above, wasn't correct. My apologies for the argument!

(And yes, in short rings are quite safe and we should all agree they are awesome.)

[mitch808]

I've road raced, autox'ed and wrenched quite a bit on my own vehicles. I've learned a lot, am always willing to learn more. But the hub centric debate is often very wrong and based on old 2nd hand knowledge from a friends cousins neighbors grandkids uncle...

Thanks foe keeping this amicable and not a flame fest. :-)

[Sylvan Lake V35]

I use the rings to allow me to run wheels on both my X5d and my X5M no issues I run them on my M with 25mm spacers and the hub ring, I have aluminum ones but on past vehicles I have had the plastic or polycarbonate ones both were fine.

[Draper]

Originally Posted by rennis

I edited my post - I went back to my source on my information, and we pulled in some other people. In short, what he explained to me, and what I relayed above, wasn't correct. My apologies for the argument!

(And yes, in short rings are quite safe and we should all agree they are awesome.)

Originally Posted by mitch808

I've road raced, autox'ed and wrenched quite a bit on my own vehicles. I've learned a lot, am always willing to learn more. But the hub centric debate is often very wrong and based on old 2nd hand knowledge from a friends cousins neighbors grandkids uncle...

Thanks foe keeping this amicable and not a flame fest. :-)