[dxb335d]

what does radial run out mean bud?

[mikem]

Originally Posted by dxb335d

what does radial run out mean bud?

Think of a buckled bicycle wheel wheel Carl, the more it wobbles, the greater the run out.

[M3-FAST]

I thought it meant the 'roundness' - ie: If it had hit a bump/pothole the wheel would have gone slightly oval but not no more than 0.3mm? It is a measure of how 'out of round' a wheel is

EDIT:

It is, the side to side wobble, like a buckled bike wheel is lateral runout

http://books.google.co.uk/books?id=m...sult#PPA299,M1

[Gibbo]

Why are you guys not putting a claim in with local Councils. If BMW say it's having a hard knock on the roads then it's surely the highways fault.

My dad had a punctured tyre and cracked wheel a couple of weeks ago (335d M Sport 18's) and has a claim in with the council at the mo. I will let you know how he gets on but that would be my route.

[SoYank]

Originally Posted by dxb335d

what does radial run out mean bud?

If you mounted the wheel on an axle and positioned a runout gauge along the circumference of the rim, as the wheel is rotated 360° the deflection of the gauge can not be more than 0.3mm.

Likewise, if you mount the wheel on a calibrated axle (one that has the mounting plate exactly 90° to the spin axis, i.e., 0% runout) and position a runout gauge at the outer edge of the rim, the gauge can not deflect more than a specific amount else the wheel would be considered out of tolerance.

[330cdsport]

Originally Posted by Gibbo

Why are you guys not putting a claim in with local Councils. If BMW say it's having a hard knock on the roads then it's surely the highways fault.

My dad had a punctured tyre and cracked wheel a couple of weeks ago (335d M Sport 18's) and has a claim in with the council at the mo. I will let you know how he gets on but that would be my route.

I tried this route a few years back with one of my previous broken rims. I enclosed photos of the pothole with a ruler in it to show it as about 5cm deep.

A week or two later I got a letter back saying that this road was checked every X weeks (cant remember the period) and that the pothole was now fixed and they had done all they were required to.

So that turned out to be a complete waste of time considering they can make up any crap to cover their arses.

[Carrera RSR]

Originally Posted by 330cdsport

I tried this route a few years back with one of my previous broken rims. I enclosed photos of the pothole with a ruler in it to show it as about 5cm deep.

A week or two later I got a letter back saying that this road was checked every X weeks (cant remember the period) and that the pothole was now fixed and they had done all they were required to.

So that turned out to be a complete waste of time considering they can make up any crap to cover their arses.

Out of interest has anyone tried their insurance company on this? Not sure what they would cover in the event of wheels and tyres being damaged on the road if BMW and the council not covering it. I guess even if they did cover the cost it would be a black mark against your no claims which essentially wasn't your fault.

Interesting case of who's to blame. The council for not maintaining smooth roads, BMW for not manufacturing wheels to withstand UK roads or the motorist for not having insurance that covers for accidental wheel/tyre damage. Obviously it's the motorists wallet either way that gets the ultimate hit.

[xenon]

It's BMWs fault. If it was the fault of the local council how come every other car forum on the Internet (for different manufacturers) is not filled with the same stories? It's because BMW hot a faulty batch of 225 wheels (the only ones affected) that were not cast correctly.

[Mark II]

Originally Posted by dxb335d

what does radial run out mean bud?

Sorry mate - been busy - as others have said, looking side-on at the wheel, it's how out-of-round (or 'egg shaped') the wheel is.

As So Yank said - if you were to mount the wheel on a calibrated axle shaft (so you know the shaft isn't out of kilter) and positioned a dial guage with the tip of the guage onto the radius (outer edge) of the rim, pre-loaded and zero'd the guage and then rotated the rim one revolution, the difference between the maximum and minimum dial guage readings would be your radial run-out.

I believe BMW are saying that should be max 0.3mm and seem to be suggesting that any figure above 0.3mm indicates that the wheel has received impact damage which caused the crack in the first place.

I don't doubt that some form of impact caused the crack but my point is why the alloy cracked: I'm not a metallurgist but as an engineer I believe that if you do a radial run-out test on these damaged wheels you may well find that the lowest reading is 180 degrees opposite to the crack and the highest reading it at the point of the crack - which at the very least suggests that instead of the crack being the point of impact it was actually 180 degrees opposite to the point of impact and therefore perhaps if the alloy material had not been flawed in the first place (by a weakness such as a casting inclusion or suchlike) then a crack would not have formed.

In my theory the impact force transmitted into the edge of the rim deformed the rim at the point of impact but the rim burst (for want of a better word) on the opposite side.

To me, the fact that the wheel isn't round is not an adequate explanation for the existence of cracks - poor quality control on the alloy is, so ergo it was a manufacturing fault and should therefore be covered under warranty.

As far as alloy casting is concerned this article is very interesting (for the techie): http://findarticles.com/p/articles/m..._/ai_n21383207

Just my tuppence

[phazon]

Originally Posted by xenon

It's BMWs fault. If it was the fault of the local council how come every other car forum on the Internet (for different manufacturers) is not filled with the same stories? It's because BMW hot a faulty batch of 225 wheels (the only ones affected) that were not cast correctly.

Definitely not the only ones affected - two of my 220's were cracked, I heard from others with 200s that were damaged, plus some old e46 drivers with cracked 18's. So it's a BMW problem, as opposed to a 225 problem.

[xenon]

^^ fair enough - a BMW problem with their OEM wheel supplier. They're probably all the same but maybe more noticeable on 225M wheels running a (hard) 30 profile RFT.

[Mark II]

Originally Posted by phazon

Definitely not the only ones affected - two of my 220's were cracked, I heard from others with 200s that were damaged, plus some old e46 drivers with cracked 18's. So it's a BMW problem, as opposed to a 225 problem.

Phazon,

Are the 220's also manufactured by Cromodora in Italy (like the 225's)?

[pjs]

Originally Posted by pjs

If I dont post for more than a week, assume I've been taken out by the German Mafia...!

Still here just in case you thought the German Mafia had taken action;

Re Claiming off the councils, clearly I cant identify a certain bit of road, especially a wide enough pot hole to do both rear wheels, as for insurance - got a £450 excess and had a £2.5k claim after I hit a dog on a motorway last year so little point.

No defence from BMW yet.

I'll have a look at the wheels shortly to see who made them and when

[scooba0010]

I worked in engineering for twenty years in metal fabrications .Now just my 2 cents i think 0.3mm run out is a very tight tolerance to be quoting on a 19" alloy wheel .I would thoroughly recommend the next member to have this problem to challenge the person to show you that at least the replacement was to spec before fitting

If it doesnt come up to spec ask for a further excuse as this is shall we say mythbusted

I am betting the service managers wish this was resolved as well and BMW proberbly want a way out as well without lossing to much face

[scooba0010]

I just done some quick maths the out side circumfrence is 1525mm approx a deflection of 0.3mm is absolutly miniscal am i getting mixed up here

Sounds like BS but some one needs to challenge there dealer NOW !

[330cdsport]

Originally Posted by scooba0010

I just done some quick maths the out side circumfrence is 1525mm approx a deflection of 0.3mm is absolutly miniscal am i getting mixed up here

Sounds like BS but some one needs to challenge there dealer NOW !

Thats what the alloy repair guy said to me - that 0.3mm was a ridiculous tolerance as he held up his digital vernier and showed what 0.3mm looked like.

Hopefully my welded alloy will be ready today.

[Mark II]

Originally Posted by scooba0010

Now just my 2 cents i think 0.3mm run out is a very tight tolerance to be quoting on a 19" alloy wheel..

Scooba - maybe somebody at BMW has put the decimal point in the wrong place

Originally Posted by 330cdsport

Hopefully my welded alloy will be ready today.

330cd - Do you know what the run-out was on yours before the repair?

[big pimp]

Originally Posted by 330cdsport

Update:

Bavarian BMW, Belfast - have got back to me and said that they get loads or rims in with similar cracks and when the test them they are always ouside the tolerances which inidicate a hard knock.

I can't be arsed fighting with them so am gonna get the wheel welded and hope that it doesnt crack again.

Prentice Portadown were the exact same with me - infact, i'll add my 'report' from them:

[scooba0010]

Is anybody going to get runout carried out on on a set of new rims ??.

[M3-FAST]

Originally Posted by scooba0010

Is anybody going to get runout carried out on on a set of new rims ??.

+1 - I can't believe a new set could be manufactured to within 0.3mm!

[SoYank]

If you could find a brand new wheel that has never had a tyre mounted nor ever been put on an axle but was out of the 0.3mm tolerance it would probably go far in disputing BMW's contention that the issue is related to impact. Further, if you then could take those specimens to a metalurgical lab and have them x-rayed or otherwise examined internally and could discern flaws, BMW's case should crack just as surely as have the wheels. It would only take a single rim.

[scooba0010]

Come on on of you guys who have paid 300 for a new rim and felt fu--- over by the BMW dealer must have issues with this

Next time you have a wheel failure ask the service guy to show you his findings them challenge him .I would go with ok its running out at more than 0.3mm, I will take a new one if you are prepaired to check the run out in my presence and that is below 0.3mm but belive me old chap if the new item is out as well we will be falling out big time