Repairs on alloy wheels

[bpsorrel]

Had an interesting chat with Tony at Wheels in Motion today (by the way, thanks Tony, car runs a dream now!)

I'd always thought that repairing cracked or flat-spotted alloys was impossible or at best, unwise! But, Tony showed me some Porsche wheels that had cracks repaired, to aircraft standard, and perfectly safe, using a welding method that hopefully Tony will come on and explain better! If only I'd known about this when I cracked one of my new CLS wheels!! The approximate cost (depnding on wheel) is around £80 for the repair!

For more information on this, please contact Tony here: http://www.blackboots.co.uk/alloywheelrepairs.php

 

[jaymanek]

Ive had wheels repaired in the past and as long as its done properly, there is no problem.

My Brabus wheels were recently damaged, luckily no cracks, just had to be reformed, came back like new.

 

[wheels-inmotion]

As the road condition deteriorates we needed to find solutions for dented/ compressed and cracked wheels.

The reason this has become so visible on the forums now is because.....
1: The road condition is pants
2: The low profile tyre
3: The runflat tyre

All three elements transport energy to the rim hence all the issues.

Solution
1: A cracked wheel needs to have the crack removed ( cut out ) and then welded/ re-shaped.

2: A flat-spotted wheel can be cold pressed on the inner dish, should it crack refer to # 1

3: A flat-spotted outer face can be cold-pressed but it would also need to be refurbished.

4: Damaged and/or broken spokes can be replaced as can part of the hoop, within reason.

Costs go from....
1: £40 to press the inner
2: £85 to press and or weld
3: £145 to press and refurbish

Very few wheel are scrap, in fact i cannot remember the last one.

This service is not just available at wim, i know of links around the UK, so if your stuck pm me.

 

[brucemillar]

Lepsoms in Kent

As mentioned in another post they repaired a cracked AMG alloy for me while I waited. 45 minutes and £45 later I left with the wheel as good as new.

As WIM says. They cut out the crack with a hacksaw then weld and press the wheel before painting. In my case the crack was on the inner side so no big deal on the paint finish. But they will do a full refurb. It is an impressive thing to watch if like me you are really sad and lonely and don't get out too much.

 

[hotrodder]

45 minutes and £45 later I left with the wheel as good as new.

I'm sorry but that just isn't true. The repaired wheel may last a long time, maybe even outlive the rest of the car but it's mechanical properties WILL be lower and fatigue life WILL be shortened.

As said this sort of topic is coming up more frequently due to the state of the roads and predilection for drug dealer rims with ruber band tyres. Couple of threads on the subject here (link to the other thread on page 3). There's info about the effect welding has on aluminium alloys in those threads so i'll try to avoid repeating it

Had a little play with google and to my surprise MB have actually published some relatively detailed info on the production of their wheels... article here

They haven't published the exact alloy used, GK-AlSi7 being a partial designation that covers a group of 7% silicon aluminium alloys with slight modifications to the other alloying elements. From the solution and aging temps given in the article i'm going to make an educated guess that the alloy used is 356.0-T6. It is one of the more weldable casting alloys but welding WILL destroy the heat treatment local to the weld. In the case of a flow formed wheel the grain structure will be destroyed in the weld and HAZ further impacting the mechanical properties...

Properties of aluminium 356.0-T6
Properties of aluminium 356.0-F i.e. as cast

AFAIK there are no regulations covering the repair of alloy wheels in the UK. Canada has some... Weld Repair of Aluminum Alloy Wheels Regulation note that welding is restricted to the rim only and with good reason IMO.

I'm wondering what 'repaired to aircraft standards' actually means in this respect? While there are various standard joint types used in the production of components, repair of a critical component would typically involve devolping a welding procedure (using an actual part or mock up), and then qualifying welders to that procedure (think, lots of non-destructive and desctructive testing). A welder could hold multiple CAA certifications (in the relevent processes and material groups) but that's relativlely meaningless i.e. they may able to produce a weld free of porosity or inclusions every time but the microstructure and mechanical properties are the result of a welder working to a known procedure. Welding procedures are devolped by welding engineers.
I guess what i'm actually asking how much 'engineering' is actually involved or is it a case of people assuming that wheels are built with a large enough saftey margin that 'it'll be fine as long as the welder is good'

 

[312 Sprinter]

AFAIK there are no regulations covering the repair of alloy wheels in the UK. Canada has some... Weld Repair of Aluminum Alloy Wheels Regulation note that welding is restricted to the rim only and with good reason IMO.

There is a catch all in the MOT test regulations stating "Welded repairs to highly stressed components such as steering/suspension arms, rods, levers etc are not normally acceptable, other than where the component is made up of sections that are welded together. In these cases the repair should appear to be as strong as the original design."

As to whether that covers wheels? Having said that I've had rims straightened and curbed lips welded. I'm less comfortable with the idea of a section removed from a rim and welded back in.

 

[hotrodder]

I'm not that conversant on MOT regs but i thought it was only steering components that were mentioned specifically with regards to welding? A quick search of motuk.uk got no mention of welding with regards to wheels, suspension page only mentions welding in relation to springs

I did break my general rule of not welding wheels last year, for my local MOT inspector no less! Was initially suprised he even asked me but it turned out he wanted curbed lips building up which i don't have a problem with (as mentioned in one of threads i linked to) as that can be done with much lower heat input into the wheel. Straightening is a cold process in comparison to welding, depends on temp but if anything going to get some strain hardening.

We did chat briefly on the subject, ISTR him saying something along the lines of despite not him not liking the idea of cracked wheels being welded it would be an advisory unless obvious flaws (cracks visible to the naked eye etc) were present. It was a while ago so might making bits of that up. Of course if the welds have been blended out then they'll be invisible to the naked eye whether on a wheel or some steering component...

It'd be interesting to see how a crack repaired wheel holds up to something like a high speed tyre blow out compared to an identical wheel that hasn't already been battered by potholes to the point it's given up