Federiconi wheels

I once brought an expensive magnesium mag for the front of the SF2 back in mid 70s. I was looking at the front end while taking a break after riding a 200km stretch of really bad gravel road in Gippsland when I noticed a crack on the rim about 50mm long. I was still 700kms away from Melbourne and had another couple of hundred kays of dirt to go. I reduced the tyre pressure, marked the start/ finish of the crack and gingerly headed off towards Melbourne stopping frequently to check the rim. Once I got back on the main coastal hwy and the crack hadn't moved it was 100mph back to Melbourne.
Got my mum to send over my original spoke wheel from Perth. Another earlier problem I had with that wheel, on a trip over to Melbourne and back [Perth], I had a problem with my front brakes having to pump them to work. Couldn't figure out what the fuck was causing it till I got back home and removed the front wheel and the bearing fell out. The housing had worn to the point that the front wheel was wobbling displacing the caliper pistons. It cost a fortune to have the hub turned out and a sleeve fitted.
Put me off mag wheels for a long time. I would never use a magnesium wheel for road conditions again.
 
Hey Kev , they certainly sound like a magalloy type from your description in particular the black appearance before polishing. It's certainly not a god idea to leave the surface unprotected unless " for display only ". If your down this way I can put the wheels through the NDT shop at work or I can send you a dye penetrant kit that although fairly crude will show up any existing cracks. Also I have a thick web front you can have that needs a minor tweek, it has a very small flat spot although I never noticed it in everyday use it was picked up on an MOT but not failed .
                              Tim.
 
troutbishop said:
I think i will see if i can pick up another set of wheels a set of std alloys would look ok till i can get them crack tested then the buyer can have a choice .
Click to expand...
Kev there's a set on Pommy eBay right now, 150 quid. Not a great price but they (probably) won't crack.

Ken
 
last night tried my own crack testing tool didn't work because i didn't like the taste of the polish i had left on the rim :P there are a set of kawasaki rims on ebay that look the same almost item no 110681746107 i wondered who copied who.
Tim i have sent an email cheers.



 
Hi All,
        Been following this thread with interest, Why does magnesium appear not to have the same shelf life as normal ally. Have just forked out for a pair of period Dymag H section wheels and now a bit worried. Cheers.
        Mark
 
It is a much more reactive metal than aluminium so any exposure to air will eventually weaken it.
I may be wrong but it seems a harder, more brittle metal than aluminium too, so maybe the crystal structure makes it less able to withstand a hard life.
 
Mark I know what you mean I wish i had never started this thread I was quite happy with my wheels before all this thinking the bike was nearly finished and ready for a run :( scared to take it off the centerstand now and worried everyone with mag wheels sorry.
                                        Kev
 
To be honest mag alloys are widely used in aviation without any real issues. Corrosion is the killer though. I'd have thought a mag alloy wheel would have a similar lifespan to an alloy one if properly maintained. Dymag offer a refurbishment sevice on all their old wheels so they must be fairly confindent in this current legal minefield.
                          Tim
 
Tim, I think aviation quality components and aviation standards of maintenance, plus the less unpredictable terrain for aeroplane wheels means that such wheels will be more scrutinised and tested than road wheels. Even certain wheel companies (I think even Dymag) did not recommend their magnesium wheels for road use, what with potholes and potential lack of maintenance. So to draw comparison there with bike wheels is stretching it a bit.

I think the same fate awaits users of carbon fibre wheels in a decade or two, as the plastic binding the fibres together will age badly and weaken. There has been a lot of discussion about this from time to time.
 
There must be hundreds of this type of wheels knocking around on the roads still, I think a fresh coat of paint should hold them together if I use two coats  :D I think they are a cracking pair of wheels :D
                                                              Kev
 
 
Fair point Grant, to be honest I wasn't thinking of aircraft wheels specifically but the problems we see with the material is nearly always corrosion related. I'd have thought the stress on a wheel on a race bike far higher than that on road bike ? Not allowing for large potholes which have the potential to fuck any wheel really. It must happen more frquently but the only wheel I remember collapsing was Carl Fogartys at the IOM.
 
There was that one on a Ducati the other week in WSB.
[youtube]http://www.youtube.com/watch?v=m1j32N2eWPs[/youtube]
 
yes Tim just get out of work and unicycle to the pub on Wednesday ok :D

Shaun
 
Trainspotter alert - collapsing wheel at IoM was Robert Dunlop.

As for your wheels Kev, they're unique and interesting, they will be a good feature of the bike.  But I would still proceed with a bit of investigation, starting with the density test as outlined earlier.  If they are Mg then a crack test will set your mind at ease, then a good Mg-suitable corrosion protection and you'll have your cool wheels AND peace of mind.

Cheers
Steve B
 
Right then wheels out and ready to test, have to remove the paint does any one know if its ok to have them blasted to clean and what blasting is best ?
                                  cheers Kev           
 
  I would ask the guys that are going to do the testing Kev. Some blast media will have a peening effect which may disguise any problems or create them... these guys should be able to give you some answers based on actual experiance http://www.dymag.com/?q=spares_refurb Or you could try putting them in a cement mixer with two dead cats and half a pint of bitter.


    Keith
 
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