Wobble Bolts

Wobble Bolts

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Discussion

Captain Muppet

8,537 posts

235 months

Thursday 29th November 2012
quotequote all
mrmr96 said:
Don't let Captain Muppet hear you saying that!!

http://www.pistonheads.com/gassing/topic.asp?h=0&a...
There should be seperate internets for engineers and non-engineers.

Everyone would be much happier biggrin

kambites

62,413 posts

191 months

Thursday 29th November 2012
quotequote all
Captain Muppet said:
mrmr96 said:
Don't let Captain Muppet hear you saying that!!

http://www.pistonheads.com/gassing/topic.asp?h=0&a...
There should be seperate internets for engineers and non-engineers.

Everyone would be much happier biggrin
I thought everyone was an "engineer" these days. I'm sure I've seen our council advertising for "refuse collection engineers". hehe

big_boz

1,684 posts

177 months

Thursday 29th November 2012
quotequote all
kambites said:
But that's the question - why do you think it's dangerous? What failure mechanism would cause it to fail where a normal bolt wouldn't?
With my admittedly limited knowledge of metallurgy i would suggest:-

A SOLID bolt will be stronger than a 2 piece "Bolt" as it is SOLID

Theoretically there is no weak point in a SOLID bolt by its very nature.

Those things have a number of weak points that i can envisage, The flange on the back of the protruding front element and the collar that sits around the flange that sits behind the flange being the two obvious ones. Given that the flange will be of a smaller diameter than the collar this WILL result in an uneven distribution of pressure on the collar.


HustleRussell

20,235 posts

130 months

Thursday 29th November 2012
quotequote all
I don't like the tensile load concentration being eccentric to the central axis of the bolt, nor do I like the reduced area of the bolt head/washer seat, but we must recognise that these things aren't known to fail. Fair play I say. Wouldn't put them on my car personally.

kambites

62,413 posts

191 months

Thursday 29th November 2012
quotequote all
big_boz said:
With my admittedly limited knowledge of metallurgy i would suggest:-

A SOLID bolt will be stronger than a 2 piece "Bolt" as it is SOLID

Theoretically there is no weak point in a SOLID bolt by its very nature.

Those things have a number of weak points that i can envisage, The flange on the back of the protruding front element and the collar that sits around the flange that sits behind the flange being the two obvious ones. Given that the flange will be of a smaller diameter than the collar this WILL result in an uneven distribution of pressure on the collar.
Don't buy a Golf based car then, because that's exactly the mechanism that the OH's Octavia uses to secure its wishbones to the chassis. hehe

aponting389

655 posts

148 months

Thursday 29th November 2012
quotequote all
doogz said:
Why?
the bolt isnt going to bend

the head isnt going to be pulled off the bolt

the wheel isnt going to fall off

big_boz

1,684 posts

177 months

Thursday 29th November 2012
quotequote all
kambites said:
big_boz said:
With my admittedly limited knowledge of metallurgy i would suggest:-

A SOLID bolt will be stronger than a 2 piece "Bolt" as it is SOLID

Theoretically there is no weak point in a SOLID bolt by its very nature.

Those things have a number of weak points that i can envisage, The flange on the back of the protruding front element and the collar that sits around the flange that sits behind the flange being the two obvious ones. Given that the flange will be of a smaller diameter than the collar this WILL result in an uneven distribution of pressure on the collar.
Don't buy a Golf based car then, because that's exactly the mechanism that the OH's Octavia uses to secure its wishbones to the chassis. hehe
Have these been tested to a similar standard to an OEM part then?

Would be interested to see some evidence to put into practice what has been said in "For" posts.

kambites

62,413 posts

191 months

Thursday 29th November 2012
quotequote all
big_boz said:
Have these been tested to a similar standard to an OEM part then?
Who knows? And to be fair the same could be said of any non-OEM bolt used anywhere safety-critical in a car.

I'm certainly not saying they're safe; I just can't see a reason to believe that they're not. It seems like a sound enough engineering solution to the problem to me; whether the implementation of that design is any good is obviously a different matter.

Edited by kambites on Thursday 29th November 11:49

kambites

62,413 posts

191 months

Thursday 29th November 2012
quotequote all
doogz said:
aponting389 said:
the bolt isnt going to bend
Why? Can you actually explain, instead of 'just cos'?
I don't understand why you think it would? I can't see where the bolt to have any bending forces on it at all.

Ultimately this is just a bolt going through a hole slightly bigger than the diameter of the thread. Why would that make the bolt bend?

E500 TAT

316 posts

169 months

Thursday 29th November 2012
quotequote all
big_boz said:
This looks ludicrous, how can these be legal?

I can not fathom what would possess someone to want to put their life and the risk of others in the hands of something like this.
You can get TUV approved ones so the above does not hold any water.

big_boz

1,684 posts

177 months

Thursday 29th November 2012
quotequote all
kambites said:
big_boz said:
Have these been tested to a similar standard to an OEM part then?
Who knows?
I am more than willing to accept that these are safe, if i can see some evidence to prove it.

If someone told you that a Wheel bolt made of Plastic was safe due to a number of "scientific" reasons that you don't understand, would you believe them?

I am not an engineer and i don't understand in any detailed way friction or pressure dynamics, so all i have to judge these on is my own experience, which tells me that something solid is stronger than something that isn't.

To your point, I know that a Skoda Octavia is inherently safe as it has been tested and proven to be as such, also i know that VAG invest millions in development in there own components and also in the testing of 3rd party supplied components.

If for instance these are deemed safe to use in Germany and are TUV certified, then this would convince me that they are safe to use in a car with my children in it......See what i mean?

kambites

62,413 posts

191 months

Thursday 29th November 2012
quotequote all
Ah so you're saying the "washer" section of the bolt will try to twist so its face is no longer parallel to the hub-face?

big_boz

1,684 posts

177 months

Thursday 29th November 2012
quotequote all
E500 TAT said:
You can get TUV approved ones so the above does not hold any water.
Bosh, Convinced, Il order some now smile

kambites

62,413 posts

191 months

Thursday 29th November 2012
quotequote all
big_boz said:
If someone told you that a Wheel bolt made of Plastic was safe due to a number of "scientific" reasons that you don't understand, would you believe them?
Depends on who the "someone" is, I suppose.

Captain Muppet

8,537 posts

235 months

Thursday 29th November 2012
quotequote all
kambites said:
Captain Muppet said:
mrmr96 said:
Don't let Captain Muppet hear you saying that!!

http://www.pistonheads.com/gassing/topic.asp?h=0&a...
There should be seperate internets for engineers and non-engineers.

Everyone would be much happier biggrin
I thought everyone was an "engineer" these days. I'm sure I've seen our council advertising for "refuse collection engineers". hehe
Good point, some engineers are rubbish.








I'm going to get such a massive hi-five when I tell the rest of the geek table about this post at lunchtime.

J4CKO

34,708 posts

170 months

Thursday 29th November 2012
quotequote all
I dotnm think these are a great idea but remember, there are five of them to attach a wheel on, I am sure they arent going to start spitting wheels off left right and centre, wheel bolts are by design over engineered for the forces they encounter.

My 944 has Aluminim wheel bolts which are very light but after twenty years I would be more concerned about those than some brand new steel "wobble bolts", ditto all the classics running about, some may be runnign about on 50 year old bolts that may have been loosed, tightened or over tightened a thousand times.

big_boz

1,684 posts

177 months

Thursday 29th November 2012
quotequote all
J4CKO said:
there are five of them to attach a wheel
Or 4...Or 3

J4CKO

34,708 posts

170 months

Thursday 29th November 2012
quotequote all
big_boz said:
J4CKO said:
there are five of them to attach a wheel
Or 4...Or 3
Usually 5 these days, cant remember last time I saw three, Citroen AX maybe ?

big_boz

1,684 posts

177 months

Thursday 29th November 2012
quotequote all
J4CKO said:
Usually 5 these days, cant remember last time I saw three, Citroen AX maybe ?
and saxos

M Powered

349 posts

179 months

Thursday 29th November 2012
quotequote all
Captain Muppet said:
kambites said:
Captain Muppet said:
mrmr96 said:
Don't let Captain Muppet hear you saying that!!

http://www.pistonheads.com/gassing/topic.asp?h=0&a...
There should be seperate internets for engineers and non-engineers.

Everyone would be much happier biggrin
I thought everyone was an "engineer" these days. I'm sure I've seen our council advertising for "refuse collection engineers". hehe
Good point, some engineers are rubbish.









I'm going to get such a massive hi-five when I tell the rest of the geek table about this post at lunchtime.
High five from me.