Redrilling wheels - has this guy found the limit?

Ok then, I am currently about to enter my final year in studying for a Bachelors in motorsport eng from a reasonable Uni. I have little experience of work within automotive design I do have a good knowledge of engineering principles. I have a good working knowledge of engineering design principles, but of course I am not as experienced as someone from the industry who does design like this every day of the week.

 

The porsche method employing no lubricant onto the clamping faces. Unless I have understood the name spigot incorrectly.

 

That's correct. No lubricant on the clamping faces.
The 'spigot' bit is the raised section in the centre which locates the wheel - it's 3 raised section on a 911, as shown:



So you apply there only, along with the prescribed portions of the wheel bolts...not on the hub, as clear in the photo.

 

I can't see the pic at work, but i can see the link, and i'm amused that you have a folder called "Detailing" on photobucket, i didn't think you were into buffing

 

So you admit you're talking textbook rubbish then?

 

It's not textbook rubbish, it's proper engineering knowledge. Look at that porsche spigot and tell me thats taking the loads from the wheel. Also as i said earlier would the prosecution like to bring forward details upon the strength of the spigot.

 

Im just seeing this now.
Im glad to say Im not a qualified Mech eng, so, that makes me an observer all my life.

Even though Ive read all the text books Ill leave them aside because a lot of them lack Important points, and that is tolerance and slack. People assume a bolt because its drawn that way will go into the hub parallel with the tapped hole. This is not true in real life. Simple as that.

Ill go far as to say Ill prove it if anyone wants, and show that an alloy wheel with a larger spigot and no ring can be tightened in a number of positions, none of them being concentric.

End of story for me.

 

Concentricity when bolting on is the goal of the spigot I agree and the spigot is the fastest, easiset and most effective way of acheiving this. The ability to bolt on wheels concentricly without spigots should in theory be possible by lug centricity with tapered bolts, although as you say brian in practice this is hard to acheive. The spigot is not a load bearing part as others have begun to suggest though.

The original point of the thread though being some redrilled wheels, which could have a spigot made to ensure concentricity.

My belief is that the original wheels in question are at a glance from a few low quality pictures structurally ok for use. The new bolt holes will be able to take the forces expected of them. Although maybe on closer inspection those mag wheels have been damaged in the past and are nothing better than nice bits of mag for recycling.

 

Don't waste your time on that, you have much better things to be doing like casting heads or writing the full workings of the mk2 suspension system. I'd much rather read those than continue on with this thread where the point changes regularly.

 

There we are

Ok, I wont bother, Ive enough to do, Ill leave quietly again

 

I quite clearly said in all my first posts that you can use the correct spigot rings.

Whats your opinion on the original subject, the redrilling of the wheels?

 

Two pictures dont contain enough info to make a possible life threatening decision on an internet forum. Thats my opinion.

 

this was my response when we debated this **** years ago.

 

I was not going to post on this thread, until the guy who is selling the wheels, replied to my questions. Which were:

Do the four holes have steel sleeves? Every OZ cast aluminum/magnesium alloy 'Rally' wheel I've looked at appears to be sleeved. I can't tell from the ebay photos if the rust on the lip of the four holes is a corroded sleeve, or witness marks, of where steel nuts/bolt heads have contacted!

What is the spigot bore diameter?

I also asked him to put photos of the inside of the wheel on the advert!

 

Quick definition:

Spigot is the bit that goes in - the hub bit.

Socket is what the spigot fits into - the hole in the wheel.

Synonymous with - Mortise and Tenon.

Goung to bed now. Will expand on this tomorrow!

 

Before I'm cast in to the horses camp (see what I did there, neigh, horse... maybe I'll leave it there), this is just my person experience.

350bhp Mk2 Golf ran 4 events, including Bedford, 500 miles to the Ring + 7.9 laps of it's hallowed tarmac, with only 1 spigot ring because I lost the others, and the replacements that I ordered were the wrong size. No failures to report.
Just to make sure I'm not branded in to any camp, I've got some more lying on my desk. Will I use them? Depends if I can find them when my car's fixed.

But here's a question that might brand me a horsey - if spigot rings are designed to be load bearing, then how come mine are plastic?

BTW, I think we're all

 

They are designed not to be load bearing....They simply locate wheel concentric to hub so that the bolts tighten in squarely.

I feel a demo coming on oh nooooooooooooooooooooo

 

I'd like to see if there is a method of bolting which will ensure concentricity every time. I know there are methods which will almost certainly make sure it is not concentric.

 

Indeed, and those methods are called real life possibilities

 

It will be the case that the spigot is offering support in certain circumstances due to high impact loading (spirited driving / low profile tyres), leverage on bolts (wide rims / wrong et). All things that were never originally planned for in the original design.
I have stated several things that could be factors in previous posts that all the text book engineers have not responded too.
Having been involved in motorsport and vehicles in general for far too long, as well as other engineering industries, I have seen loads of paper engineers that regularly produce epic fails due to not having much practical experience.
Just because you are qualified in a certain area does not mean you have the absolute knowledge to produce the ultimate product. Plenty examples of folks getting it wrong with dire consequences.
I personally like to reduce as many of the potential problems as I can when building and designing things. For this reason I would always recommend the wheels should be supported on the spigots of the drive flanges or discs for arduous use.
This is just my own opinion on the matter based on a lifetime of working on road cars and buses, and also years spent involved in motorsport including hill rally 4x4, rally and race cars.