Lancia Motor Club

Model Technical and Interest => Fulvia => Topic started by: Beckerman67 on 29 June, 2020, 10:54:32 AM

Title: Cromodora Refurbishment
Post by: Beckerman67 on 29 June, 2020, 10:54:32 AM
I've always used Lepsons in Kent for alloy refurbs, not the cheapest but always excellent work.
As I've just acquired a Fulvia with Cromodora 14x5.5J alloys, I thought I'd enquire as to how they deal with them, given the magnesium issue.
I spoke to a very knowledgable lady who took me through the process.
1) The wheels are sent away to be dipped/stripped as the on-site acid is too harsh for the magnesium.
2) Once stripped they are sent elsewhere to be 'Chromated', a special primer to seal the magnesium.
3) On return they are first 'wet painted' and then powder-coated on top.

How much for this service? Well, a regular 14" alloy is 70+vat. The above process adds an extra 125+vat to each wheel!
That's 936 inc vat!
A set of replica 14x6J from Germany is around 725 including centre caps and bolts delivered.
Thoughts anyone?

Title: Re: Cromodora Refurbishment
Post by: peteracs on 29 June, 2020, 11:41:37 AM
I am guessing the significant extra cost is due to 3 companies being involved and hence paying double profit margins. Ideally you need someone who handles Mag wheels in house as standard and I would think the cost will then be nearer to the normal alloy wheels.


Title: Re: Cromodora Refurbishment
Post by: Richard Fridd on 29 June, 2020, 11:43:14 AM
Offset? Will the 6J's foul the wheel arches? (Depending on tyres fitted)

Title: Re: Cromodora Refurbishment
Post by: Beckerman67 on 29 June, 2020, 12:34:18 PM
 Advertised as specific to Series 2 with offset of 22.5mm and hub bore of 70mm. Also do Series 1 specific with 84mm hub bore and the same offset.
 Just noticed that both are currently out of stock in silver!
 Company is Bielstein

Title: Re: Cromodora Refurbishment
Post by: simonpen on 29 June, 2020, 02:31:23 PM
I didn't realise the S2 Chromodora wheels had a magnesium content. I have some S1 fitting 13x6 Chromos which certainly do and have decided not to go with the Chromate process. Partly because of the cost and finding anyone to do it and partly because I am not sure exactly what it does, but if all it does is to stop gasses escaping from the wheels and ruining the paint job I think I can live with that on my less than perfect car.  More compelling is whether they need annealing, I have read dire predictions from internet types who say old mag. wheels are dangerous due to imminent cracking caused by stresses built up over time.  Any one have any experience of this?

Title: Re: Cromodora Refurbishment
Post by: nistri on 29 June, 2020, 06:23:25 PM
The Cromodora 5.5 alloys were standard on the 2000 HF coupe and fit very well on S2 Fulvias. They have also been remanufactured new (not with Mg but with cheaper Al alloy) and cost about 700 pounds. I have used Mg alloy wheels (restored) for many thousand km trips across Europe without any problems (there are 6 J and don't stick out too much). If in doubt, the wheel condtion can be assessed with X-rays. For the same size there is a significant difference in weight between Mg and Al wheels, Andrea

Title: Re: Cromodora Refurbishment
Post by: Lightweight_911 on 30 June, 2020, 01:20:46 PM

One of the best guys in the UK when it comes to restoring magnesium wheels is Steve Turner at TPCS in Melksham, Wilts: (

The correct process is not cheap though (it wouldn't surprise me if Lepsons send customer wheels to him for some/all of the work) - & he is in great demand so there's invariably a waiting list ...


Title: Re: Cromodora Refurbishment
Post by: Beckerman67 on 01 July, 2020, 08:36:17 AM
 Yes, I found TPCS after a Google trawl. Unfortunately they do not offer a 'one-stop shop' service either. Their website quotes "We DO NOT fill, or prep items for a smooth finish before painting." They recommend Ian Jemison Engineering for that part of the process.
 It would seem that if you want a refurbished set of Cromodoras, new centre caps, wheel bolts and tyres, it is going to prove HUGELY expensive and you still have no guarantee of the internal structural integrity of the wheel unless it is x-rayed!

Title: Re: Cromodora Refurbishment
Post by: lancialulu on 01 July, 2020, 10:29:42 AM
I have just restored a set of 6Jx14 cromodoras. I have had these types of wheels on my fulvias for years so am aware of the gassing problem. 2 sets I had done locally have not deteriorated in 10 years, but now they wont touch any more (too much trouble). So I resolved to try to strip these set my self.

I used Starchem Synstrip stripper. Very nasty stuff so you need to take precautions. It can burn through clothes and stings like hell, so with well protection to eyes face and body I applied this all over and waited an hour then used a wire brush to agitate it. It kinda dries so you dont have much time. Gentle pressure wash (make sure you dont spray unwanted things as it is still potent), then apply another dose. After three doses I was down to the green cromate primer. The stripper does not touch this so I left it at that stage, and gave the rims a good soaking (twice) in hot water and let them dry out for a couple of weeks in a low humidity environment. I used an aluminium loaded epoxy putty (Devcon) to make good the minor corrosion the wheels had mostly round the little hub cap area.

I then took them to my local paint shop and consulted with them. They found a DuPont wet etch primer designed for mag alloy (I dont know - trade secret). They baked the wheels for a day to de gas them (I was confident this was the braces bit as they were fully dry), they then wet painted them at ambient primer (flash over) colour coat and laquer. Cost 200.

I am happy as the casting detail on the rims has not been lost through blasting or to thick paint. It was messy but rewarding project.

Title: Re: Cromodora Refurbishment
Post by: Beckerman67 on 01 July, 2020, 10:35:12 AM
Thanks for that. Seems to back-up the old adage 'If you want something doing,.......'

Title: Re: Cromodora Refurbishment
Post by: angelorange on 06 September, 2020, 10:15:38 AM
Be very very careful restoring magnesium alloy wheels - prone to internal cracking and corrosion. Chromate is there for very good reason!

Such alloys are common in aircraft industry such as Helicopter gearbox housings but these require clean after every useage at sea.

Another specialist Ian Jemison is up near York:

They have plenty of experience refurbishing competition wheels where stresses are higher than gentle smooth road useage.

Oven before protection and painting process is vital.