Refurbishment of Thema 16V Turbo wheels for Beta Spider

[mangocrazy]

It's taken me at least ten years, but I've finally had the set of 15" Thema 16V Turbo wheels refurbished that I've been squirreling away. The wheels were in pretty fair nick, with only a couple of dings that needed attention, although the lacquer had crazed in places allowing minor corrosion into the surface of the ali. You'll have to take my word for this, as I didn't take 'before' pictures.

Pics of the wheels post refurb are at the end of the post and with a new tyre fitted. I've got a full set of 5 wheels (including a spare) and they all look spot on. All the photos were taken fairly late in the day, with low directional sun, so the anthracite colour you see is slightly lighter than it would be in the metal. The sun was so low that it was quite difficult to keep my shadow from intruding into the photo, hence no 'square on'  pictures.

The back of the wheels probably shows the truest representation of the wheel colour, but with a metallic shade the wheels change colour with the ambient light. The white stuff on the rear tyre walls is just tyre mounting soap. I'll wash that off before the wheels are put in service.

The colour is a mid-anthracite and the wheels were refurbished by a company called Powdercoating Shropshire. I heard about them through Bad Obsession Motorsport (the Project Binky chaps) and reasoned if they used this company then they must be good, as BOM are obsessive about stuff being done right. I had a good chat with the guys and they told me the 5 steps that all wheels go through (6 if you include dent/ding removal) in their powder coat process:

1. Any tyres removed and wheels dipped in stripping solution to remove old lacquer/powder coat.

2. Wheels aqua-blasted to remove any remaining material and get wheels back to bare metal. Grit blasting is way too aggressive, so they use aqua-blasting, basically a slurry of water and finely ground glass beads.

3. Bare wheels placed in the oven for a set time and temperature to de-gas (if this isn't done, coatings can bubble due to trapped gas).

4. Wheels primed and baked for set time/temperature.

5. Top (finish) coat applied and wheels baked for set time/temperature.

Most wheel refurbishers will miss out 2 or 3 of these steps to get a quicker turn around. I've heard a number of refinishers say things along the lines of 'powders are so good these days, you don't need a primer'. If anyone tells you that, walk away. Likewise if they use grit to blast your alloys.

These Thema wheels are 15" with a rim size of 6J (Beta alloys are 14" 5.5J). After some consideration I opted for a conservative tyre size choice of 185/60 R15 Vredestein Sportrac 5. This keeps the tyre/wheel rolling radius within 0.5% of the original 175/70 R14 setup that Betas left the factory with.

[peteracs]

Hi

They do look well, interesting process, will be asking my local company how they handle them.

I know it was a while ago, but how much did they charge for the process?

Also I am about to have my original alloys refurbished, the big question is what colour I have them painted? Any suggestions? My car is white which may sway the colour choice.

Peter

[mangocrazy]

Hi Peter,

From memory it was somewhere around £300 - £350 for five wheels, including tyre fitting after the powder coating process. I'll ping Andy on Facebook and ask him for a quote if you like. How many wheels, what size and would you require tyres removing/refitting? I doubt if the colour would make much difference.

On the question of colour, I initially thought 'white'; but on thinking about it there are as many shades of white as there are any other colour and colour-matching would be very difficult. A light silver/alloy (as close to OE as possible) would be my choice I think.

Graham

[WestonE]

Hi Graham

A nice looking job and one of those cheer you up visible progress jobs. For a White car I think I would go with a gun metal metallic or maybe gold with a brown interior. Silver on white can look bland and white would be impossible unless bodyshell matched to a white car.

Eric

[peteracs]

Hi Eric

They will not be white, have seen photos of that on Spider and not to my taste. Also not a fan of silver and think a darker grey is getting the thumbs up, just have to decide an exact colour. I do like Graham’s wheels shown above.

Peter

[WestonE]

Hi Peter

The other common choice are the Integrale 7x15 Pepper pot wheels  which come in gun metal grey. I think the 15 inch wheels really suit the spider design and agree with Graham that huge tyres are not needed and on cars without power steering not wanted either. I will run 195 x 15 x 50 but they will be track crossover sticky Yokohamas. Just one of the reasons why I installed power steering.

Eric 

[mangocrazy]

Yes, on thinking more about it, silver would look a bit anaemic. Unfortunately my wheels are in France so I can't pop round with one to see what they'd look like on your Spider, Peter. Glad you both like the wheels, I'm very happy with the result.

[peteracs]

Hi

I have been emailing a local company, Classic Coatings in Grantham, and sent him Graham’s comments above. Below is the response of Andy at the company. I chose them as being close by to me and having good independent reviews.

Personally, feel comfortable with response. I have more than 5 wheels so have agreed to take them all over and pick the best 5.

Peter

————————-

Response by Andy

1. Any tyres removed and wheels dipped in stripping solution to remove old lacquer/powder coat.
All our wheels are chemically stripped to remove the old finish and pressure washed to remove residue acid and paint prior to working on the rims

2. Wheels aqua-blasted to remove any remaining material and get wheels back to bare metal. Grit blasting is way too aggressive, so they use aqua-blasting, basically a slurry of water and finely ground glass beads.

All our wheels are tdry blasted with a 70 grit silicone free aluminium oxide, this is fine blasting media and cleans and keys the rim for priming it does scare the material, we have tried aqua blasting but it doesn't clean the corrosion sufficiently and can often leave the rims damp and covered in blasting media.

3. Bare wheels placed in the oven for a set time and temperature to de-gas (if this isn't done, coatings can bubble due to trapped gas).

All our wheels are degassed  at a constant high temperature to bleed air from the coarse grain aluminium, we then subsequently powder the rims at a lower temperature thus preventing further air to bleed from the wheel rim.

4. Wheels primed and baked for set time/temperature.

All our wheels are primed and green cured prior to having a base coat applied. green curring is essential to ensure molecular bonding of the primer base coat and lacquer.

5. Top (finish) coat applied and wheels baked for set time/temperature.

Top coat? i suspect that this company is using a 2 coat system priming and top coating in basic colours often used by powder coaters to carry out cheaper refurbishments. We have always used a 3 coat coat system primer, base coat and lacquer. This method allows us to colour match a lot more accurately and tint the base coats to achieve a closure colour match ; essential when carrying out single wheel refurbishments.

I hope this answers your questions; we have used this method successfully now without any issues but again if you have further concerns please contact me further...

Regards

Andy

Classic Coatings Ltd
Unit 4 Limesquare Business Park
Londonthorpe Lane
Grantham
NG31 9SN

[mangocrazy]

Hi Peter,

I'd say from reading between the lines that Classic Coatings follow the same regime as the guys I use. I suspect my terminology in point 5 may have been a bit off leading to confusion. I'm pretty sure Andy at Shropshire Powdercoat applies a finish lacquer coat, in the same way that Classic Coatings do. I'd be very happy using those guys, they seem to cover all bases. Andy at Shropshire Powdercoat has a range of blast media available and uses the most appropriate, depending on the substrate and level of corrosion.

I'd say both firms are essentially singing from the same hymn sheet and quality of work will be comparable.

Graham

[peteracs]

Hi Graham

That was my conclusion and am going to take my 15 rims to pick the best 5.....

Peter

[mangocrazy]

Sounds like you've cornered the market in Beta alloys, Peter...   

[peteracs]

Especially when you realise I also sold 4 a while ago....

Peter

[mangocrazy]

I spoke to Andy at Powdercoat Shropshire today, and it's the second piece of health-related bad news in 2 days. He has been confirmed with kidney cancer, and will undergo surgery next week for it. He will be out of action for at least 6 weeks and possibly longer. Following on from news of Guy Croft's passing, also from cancer, this is a really unwelcome development. Get well soon and completely, Andy...

[unclejam]

Your wheels look excellent - do you have any pictures of them fitted to the car?  I ask because I also spotted some used Thema wheels which I thought would work well on my 1980 Spyder?

[mangocrazy]

The wheels (and car) are in France, but fortunately so am I at the moment. It's been a year since the last visit and I'm trying to fit some Spider-fettling in with the required house-bothering... Wheels aren't fitted to the car yet and the car itself is currently in a huff and refusing to start, so some investigative work is needed. First step will be to check wheel to suspension/bodywork clearance, as the offset is different to the standard Beta wheels. I've done the sums and ordered up what I think are the correct spacers. All I have to do is to trial fit them and check if my calcs were correct.

And probably order longer wheel bolts. Or convert to studs. Or whatever...

[unclejam]

Good luck with getting the car started.  Elsewhere in the forum advice, I read that these wheels, fitted with 195x50x15 tyres should fit correctly, with no rubbing or offset issues.
Let us know how you get on.