50 replies to this topic

[StephenSLR]

The load is designed to be carried by the centre hub, the nuts are just for securing the wheel.

Just out of curiosity, what size is that centre lug on a HQ?

s

[TempesT]

Chopper I cant find any reason why the center locator would hold any load what so ever and i believe that statement to be incorrect.

As close a fit as the center locator ever was it would always have to be a smaller diameter than the wheels center bore to allow ease of fitment and theoretically could not take load.

What the center bore locator's roll is exactly as the name suggests, they center the wheel on the hub so that the studs are not in contact with the bores of the wheel. Why is this important. As I understand it what hold the wheel onto the hub or better put what takes majority of the force is the friction between the wheel mounting face and the hub. The nuts properly afixed to the studs applied force mating these two faces together.

If a wheel is not centered and then affixed you will create point loading and a variance in the force distribution across the studs. This can also result in the scenario where a stud is taking the load instead of the friction between the two mounting surfaces, Effectively the bolt will come under a double shear load, which in this circumstance, the stud is not designed to take and introduces the chance of failure.

my 2c

[StephenSLR]

BMW is (from memory) 74.5mm

I think BMW have a few different sizes depending on the model. My hub rings are 69.6 / 72.6 and they're a snug fit.

s

[StephenSLR]

What the center bore locator's roll is exactly as the name suggests, they center the wheel on the hub so that the studs are not in contact with the bores of the wheel.

These days with conical nuts and mag nuts that fit into the wheel holes they'd align the wheels up correctly right?

With the HQ's having a slightly different PCD do you have to file away the bores? Also with a larger centre locator would you have to widen a Commo wheel centre hole to suit?

s

Edited by StephenSLR, 08 November 2011 - 06:54 AM.

[TempesT]

Ok you should probably do a search on Hub-centric vs Lug-centric. There is nothing like your own research!

But!!! It is a common misconception that Hubcentric wheels carry the weight of the car, it is always the friction force between the two mounting surfaces as a result the of force of correctly torqued bolts.

http://forum.miata.net/vb/archive/index.php/t-127227.html
Read this thread it covers most of the obvious.

Im 3^rd / 4^th year mech. Engineer working in a design and cert. roll and after making that statement last night even I sort further information to reassure I was happy with my statement.

What I will tell you in regards to having a center bore locator on your rims is that it is cheap insurance. I say that because there is a greater chance that you will center the wheel on the hub with this set up and avoid any off center loading that may be introduced by the various centering style nuts.

Its too later to address this issue after you have lost a wheel.

PS it is very, very, very bad practice to bore out a hole to make it fit. The friction force between mounting faces as a result of the torque on the stud is calculated at an ideal state. That being centered wheels with fasteners having symmetric loading under the fasteners ect. Even with the included safty factors the slight introduction of this sort of a change will throw out all of the engineered calculations and could result in a chain of events that could result in losing a wheel.

I am not versed in the correct procedure regarding having a larger hub diameter than the wheel center bore. I can see a couple of options. Have the center bore widended (depending on what the wheel will allow), custom hub? (I take it you have the hoppers hub, could this be machined down?), different wheels.

[StephenSLR]

PS it is very, very, very bad practice to bore out a hole to make it fit.

I agree.

I take it you have the hoppers hub, could this be machined down?, different wheels.

You may have misunderstood, I was asking out of curiosity.

I do have the correct Commodore sized locators, they are interference fit and if they were HQ the Commo stockies wouldn't have fit. I also have Commo stud pattern/PCD both front and rear.

s

B.Eng. (Mechanical)

Edited by StephenSLR, 08 November 2011 - 08:52 AM.

[TempesT]

haha! there are a few of us on here then lol

[StephenSLR]

haha! there are a few of us on here then lol

True and sure I may have a degree but I never discount the word of people in the field as they are often far more knowledgeable. They get to experience results first hand and see all the variables that come into play that can make short work of what seems to be 'good designs'.

s

Edited by StephenSLR, 08 November 2011 - 10:10 AM.

[TempesT]

True and sure I may have a degree but I never discount the word of people in the field as they are often far more knowledgeable. They get to experience results first hand and see all the variables that come into play that can make short work of what seems to 'good designs'.

s

very ture and a statement I fully agree to.

[StephenSLR]

i recon these would look good on it!

What do they look like without the centre caps? Curious to see if they'll look a bit more like hotwires.

What offset? I notice they come with different offsets dependent on what size and model they're off.

s

[orangeLJ]

very ture and a statement I fully agree to.

Sheesh, for a mechanical engineer you have terrible spelling and grammar

Actually, that would make you an excellent engineer! The best engineers I have come across dont speak much English! haha.

Chris
b. bus (marketing)
b. smartassery




(all in jest)

[StephenSLR]

Sheesh, for a mechanical engineer you have terrible spelling and grammar

I've noticed this a lot, particularly lecturers.



s

Edited by StephenSLR, 08 November 2011 - 11:52 AM.

[TempesT]

Ohhh man i fail at spelling and grammar especially on the fly. I’m just lazy don’t take the time out to look at what I’m typing.

I will attempt to address that OJ, most of my attention is actually on calculating the natural frequency of a reduction gear system atm loll.
don’t stress, the numbers are correct....

[TempesT]

What do they look like without the centre caps? Curious to see if they'll look a bit more like hotwires.

What offset? I notice they come with different offsets dependent on what size and model they're off.

s

I think they look like shit without the caps lol. Ill grab a pic and throw it your way the next time I have a chance.

dont know the offset but they are the same as these....
http://felgenkatalog.auto-treff.com/

Edited by TempesT, 08 November 2011 - 02:02 PM.

[orangeLJ]

Ohhh man i fail at spelling and grammar especially on the fly. I’m just lazy don’t take the time out to look at what I’m typing.

I will attempt to address that OJ, most of my attention is actually on calculating the natural frequency of a reduction gear system atm loll.
don’t stress, the numbers are correct....

Only having a dig man!

I honestly couldn’t give two hoots how people spell or punctuate their sentences, I'm just as terrible (if not worse) most of the time!

I just saw an opening for me to have a crack at another profession and went for it! haha.

A company I used to work for manufactured container forks and other heavy machinery, the head engineer was a polish bloke, second in charge was a Serbian, both spoke terrible English, typed was excellent surprisingly, written was ok.

The plebs of the office were a couple Asian guys and the middle level stuff was all aussie!

Takes all kinds I suppose!

[TempesT]

Ok Chop. I didn’t mean to come across rude. It was mentioned on the first page by another member and your statement could (and was by me) have been misconstrued. I think we are all on the same page now lol.

[StephenSLR]

dont know the offset but they are the same as these....
http://felgenkatalog.auto-treff.com/

There's a few different 'styling 5' on that page, they all look somewhat different particularly the outer rim and have many different offsets. There should be a stamp on the inner hub the letters ET followed by offset number if memory serves me correct.

s

[TempesT]

they are the Kreuzspeichen-Styling, when i got them I went googles all the numbers. They are a 15x7 not a real "deep dish" but a nice lip and the alloy cleaned up very well.

I work 250km from home so ill have a look on friday for you.

[StephenSLR]

they are the Kreuzspeichen-Styling

Taking another look they actually look like the Kreuzspeichen-Styling TRX as the spokes sit in a rim within the rim, the spokes on the Kreuzspeichen-Styling go all the way to the outer rim.

s

[dattoman]

Engineering students are a pain in my ass
Especially the wannabe ones making stupid little cars for projects
Trying to understand hydraulics and making things they think will work... then realising in the real world they don't .... grrrr