[mikeo]

BIMMERPOST / Classifieds

Asking Price:

None

Item Interest

As you may know, 8mm wheel spacers are nearly unobtainium, as no supplier is currently producing them for BMWs, which is a shame--they're a great size.

Velocity Motorcars has just produced a great line of BMW spacers and is willing to do a special run of 8mm spacers with hub extenders (the best way to do spacers) that fit E9x 3 Series and E8x 1 Series if there are enough of us interested.

Here's the link to more info about this new line of spacers and near the end of the post a sign up list for the 8mm spacer.

[BMW MotorSport]

That's strange I carry 8mm spacers no problem. Let me know if you need some help with this.

Regards, Richy

Edit: 8mm spacers were discontinued. I am still trying to get a manufacturer to offer them though.

[mikeo]

OK, I'll bite. PM me all the info on your 8mm spacers.

[Orient330iNYC]

huh? how can you have an 8mm spacer that has an extender if the stock hub lip is about >10mm on some cars?

this is a scary quote from what i think is someone from that company:

Originally Posted by vmcllc

Spacers are 100% safe to use as long as you install them properly....and all that's required to do that is make sure the wheel hub face and extension are free from corrosion and scale...that's all...

You may think the hub extension that holds your wheels concentric to the hub is transmitting the loads from the wheel to the hub, but that is only meant to locate the wheel onto the hub. The bolts/studs provide the clamping force that takes the load...

Spacers have been around for a very long time...for the very same reason they are today...they work and they get the job done...

Originally Posted by tirerack

With the exception of a very limited number of older exotic vehicles, the center hub is the load bearing area. Lug studs and bolts have a limited shear strength. All of the wheels that we sell are hub-centric we refuse any application that is not. The basic differnece is that the lug studs are designed to hold the wheel against the hub, not to hold the car up. The issues that can be created by "lug centric" wheels range from minor (vibration) to very major (wheel loss) under different driving conditions. If you plan on driving at all aggressively get a hub-centric wheel. Your factory wheels are hub centric for a reason.

[VMRWheels]

Okay, lets examine this a little more objectively. In my opinion, both TireRack and VMCLLC presented their information incorrectly.

Originally Posted by vmcllc

You may think the hub extension that holds your wheels concentric to the hub is transmitting the loads from the wheel to the hub, but that is only meant to locate the wheel onto the hub. The bolts/studs provide the clamping force that takes the load...

The reality of it is the bolt/studs do provide clamping force, however that clamping force translates to load bearing ability due to the coefficient of friction between the two mating surfaces created by the clamping force.

For example, A 14mm bolt torqued to 80 lb-ft exerts about 8700 lbs of clamp force. A wheel using 5 of them, with wheel-to-hub interface friction coeffecient of just 0.1 should not slip until asked to support 4200 lbs or so. So, in theory, each corner of your car could hold 4200 lbs based on the clamping force of the wheel.

Originally Posted by TireRack

With the exception of a very limited number of older exotic vehicles, the center hub is the load bearing area...lug studs are designed to hold the wheel against the hub, not to hold the car up.

So TireRack's claim that the center hub is the load bearing area is a bit misleading. I think most people think the "center hub" is the center protrusion of the hub, the protrusion that centers the wheel during installation. In my opinion, it's silly to assume this tiny protrusion is the weight bearing area and that the bolts merely hold the wheel to the hub. The bolts hold the wheel to the hub at a certain clamping force and this clamping force translates to a friction coefficient that supports the weight of the car.

Anyhow, that's my take on it...take from it what you will...

[mikeo]

I think Ty's explanation is the winner! Now, let's get back to 8mm spacers--who has them or who wants them?

[Orient330iNYC]

ah, reading the thread, its a flat 8mm spacer and a separate hub extender.
that makes more sense than a one piece.

[chad@velocity_motorcars]

Originally Posted by Orient330iNYC

huh? how can you have an 8mm spacer that has an extender if the stock hub lip is about >10mm on some cars?

this is a scary quote from what i think is someone from that company:

This is an old thread but just came across it so I would like to clarify what has been said....

The reason that you can have an 8mm spacer on a car with about a 10-11mm hub extension is that you provide a separate piece that's pressed into the hub that EXTENDS the hub out....you cannot produce an integral spacer with a hub...just won't work...so you have to make it into a 2-piece design....

Originally Posted by VMRWheels

Okay, lets examine this a little more objectively. In my opinion, both TireRack and VMCLLC presented their information incorrectly.



The reality of it is the bolt/studs do provide clamping force, however that clamping force translates to load bearing ability due to the coefficient of friction between the two mating surfaces created by the clamping force.

For example, A 14mm bolt torqued to 80 lb-ft exerts about 8700 lbs of clamp force. A wheel using 5 of them, with wheel-to-hub interface friction coeffecient of just 0.1 should not slip until asked to support 4200 lbs or so. So, in theory, each corner of your car could hold 4200 lbs based on the clamping force of the wheel.



So TireRack's claim that the center hub is the load bearing area is a bit misleading. I think most people think the "center hub" is the center protrusion of the hub, the protrusion that centers the wheel during installation. In my opinion, it's silly to assume this tiny protrusion is the weight bearing area and that the bolts merely hold the wheel to the hub. The bolts hold the wheel to the hub at a certain clamping force and this clamping force translates to a friction coefficient that supports the weight of the car.

Anyhow, that's my take on it...take from it what you will...

Ty...according to your explanation...all you did was expanded on what I already said....and explained how the CLAMPING FORCE, which is induced by the bolts, is what takes the load...

But your are correct in stating that Tire Racks explanation is way off target and completely false..

Just a note...the coefficient of friction for steel on aluminium is actually .61 not .1 from your example above...but where you should be looking at is Aluminum on Aluminum which is where most people are concerned with(aka. spacer hub) but the coefficient of static friction for this is about min 1.05..

[theblackmamba]

Any word or pics on how these things fit?

[chad@velocity_motorcars]

This is a cross section to show just how you can put 8mm spacers on and regain you hub to locate your rim...

[BMW MotorSport]

Hey guys GREAT news, I found the 8mm spacers. Took some time but have them ready to special ORDER. Let me know guys.

[cgnahc]

spacer + ext. bolts...$$ PM me.

[BMW MotorSport]

Originally Posted by cgnahc

spacer + ext. bolts...$$ PM me.

PM sent, thank you. I will have these in STOCK in a few weeks.

[kmarei]

can you please PM me the cost for 2x 8mm spacers with the extended bolts?
thanks!