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Discussion Starter · #1 · (Edited)
First of all I want to say how helpful this forum is, and "thank you" to all the contributors. What a valuable resource SaabCentral is. Thanks!

I bought a used 90 SPG about a month ago and I've been working on it every spare minute I get. I took all the wheels off last week to do the brakes and discovered that one front wheel has hit a curb or something and has a small deformation on the edge of the inner rim. I called what is apparently the only wheel shop in St. Louis that straightens rims. They told me $85-$145 depending how bad it is. I told him that sounded like a lot, and asked, "What do you do to it?" (I have to confess that I was playing dumb. I figured that unless there's some high tech equipment involved, I could do it myself with a little more information.) Bottom line is, they apply a little heat, beat the dent out, and then paint it.

So, I've got an oxycetaline torch and a 3 lb maul. I've straightened several steel rims before (used to live in pot holed Central America) which mainly consists of just beating the h3ll out of them until they're straight. But I'm not very familiar with alluminum, and I don't want to damage or weaken my precious SPG wheel. If anyone has any experience straightening an alloy wheel please chime in. My dent is really quite small.

Thanks,
Steve
Wildwood, Mo.
 

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Pay the professionals.
If you beat it with a hammer it will break. If you straighten it with a press, it might break later at a bad time.
If you insist on trying, anneal the aluminum before you try to bend it. Aluminum anneals at a temperature only a couple of hundred degrees before it melts, it's hard to do with torches; it will certainly ruin the finish. Unless you're familiar with annealing aluminum, there is a high risk of ruining the wheel.
 

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I second the "pay the professionals". I'm assuming you're talking about the place in Bridgeton on the Rock Road. They did a Super Aero wheel for me not too long ago and they did a great job. Totally blasted the wheel, straightened and painted.
A good used SPG wheel will be a little hard to find in the St. Louis area. If you want to go that route, check out Speedway Salvage (its a u-pull it place) in Madison, Il, across the highway from Gateway International Raceway or call around or ask your local indy shop where to look....
 

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Discussion Starter · #5 ·
Jim,

Thanks for the advice. You're always a voice of prudence and wisdom. You drove me to the dictionary to look up "anneal = the process of heating and slowly cooling a metal to make it stronger and less brittle." It sounds to me like you know how to do it. Can you tell me more? I'm just one of those DIY kind of guys. The dent is small and on the inside of the rim. I don't think that the localized heat will even be enough to discolor the paint on the outside of the wheel. Would propane be a better heat source than oxycetaline? I have both. Please tell me more.

Sam,

So you're the guy picking over those 900s at Speedway and Pick 'n Pull before I get there? :D You're right, there aren't any SPG cars in the St. Louis area salvage yards. I've already looked locally for a wheel with no luck. There is a set of 16" aero wheels on Ebay for $300, but I can't swing that right now. I'd like to get them for my wife's 91 TC, but...

Yea, it was the wheel and hubcap place on the Rock Road, which is about 40-45 min. from my house. I'll probably end up going there, unless I can glean enough information to get the confidence to do it myself. I figure, if it took genius, would he be working at the wheel and hubcap store on the Rock Road? No disrepect intended. I'm just a working guy too, but figure I'm at least as smart and capable as the next.

Hey, please email me. I'd like to know other Saab owner in St.L. [email protected]

Sc
 

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O.K. Here's the backyard mechanics' best bet for annealing aluminum:
Set your Oxy-acetylene torch to a highly carburizing flame; the kind that deposits a thin layer of soot on the surface you apply it to. Coat the dented area of the wheel with a thin layer of carbon. Readjust your torch to a very slightly carburizing flame; that's the kind that has a double blue cone at the tip. Adjust it so the secondary blue cone is about the same length as the inner blue cone. Heat the aluminum gently and evenly (to avoid distortion caused by uneven expansion) until the carbon film burns off. If you do it right, the metal will reach about 1200 degrees and the carbon film will disappear all at once as the metal reaches the correct temperature. Let it cool. Carbon burns off at about the right temperature to anneal most aluminum alloys. Then straighten the wheel on a press rather than using a hammer. If it's bent a lot, consider straightening halfway and then repeating the annealing process; this prevents cracking.

This is a brief description of how to proceed. Metalwork like this is tricky and requires experience, but we all start getting our experience somewhere, you may as well start here. Good luck, you're going to need some (there's a lot of luck involved in your first few attempts to anneal/weld/straighten aluminum).
 

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Steve Corgan said:
They told me $85-$145 depending how bad it is.
Get a used one. It's just not worth straightening for that money, even before you consider the risks of cracks.

One of mine (the umpty-spoke sunburst allys) had a bloody great ding in. £20 later, a good used rim, and the old knackered 'un fetched a fiver in scrap.
 

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Discussion Starter · #8 ·
Jim,

You're a man of much knowledge and many talents. Thanks for that information. I really think that I could do it, but I'd have to fabricate a press of some kind out of a hydralic jack and something with an appropriate radius to make contact with the wheel. In addition, after getting the tire off (since my last post) and examining it closer I can see that the dent is not just in the edge of the rim as I originally thought, but the adjacent part of the wheel is also flattened a little.

Since there doesn't seem to be any compatible used SPG wheels available locally, I decided to jump in the 900S and carry it up to the Wheel and Hubcap Store. When I got there, I looked around at their shop and they are seriously into the wheel business, which comforted me. So, for $100 they'll have my wheel ready before noon tomorrow.

You're instruction, though Jim, is not for naught. My 87 900S has a similarly dented wheel that I plan to practice on using the technique you suggest. Like you said, we've all got to start somewhere. And if I screw it up, that wheel will be much easier to replace.

Thanks for the help,

Steve Corgan
 

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... any compatible used SPG wheels available locally ...
I can't even find compatible wheels in general for my '89, tirerack has 'em untill I say it's a SPG (or an '89...something of that nature) :(
Evil fake 5 lug pattern, just want a winter rim set and a summer rim set.
 

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fetchitfido said:
I can't even find compatible wheels in general for my '89, tirerack has 'em untill I say it's a SPG (or an '89...something of that nature) :(
Evil fake 5 lug pattern, just want a winter rim set and a summer rim set.
just take the pin off. It's a pain to bolt the wheel back on, but VW guys deal with it all the time.
 

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Jim - you reminded me of the time a friend of mine tried to weld a mag (as in genuine magnesium halibrand) wheel - we advised him not to (hey, you know how hot that stuff burns??) - he (being 18, us being 17, knew far better) did so anyhow - man that sucker burned hot! Actually burned the concrete of is fathers garage floor (not very pleased). At least I prevented him from tossing WATER onto it - grabbed a bag of flour from his mom instead -

Every time I see or hear of a torch near an alloy rim I see Greg - running like the devil was chasing him - away from his burning wheel!
 

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Discussion Starter · #13 ·
fetchitfido said:
I can't even find compatible wheels in general for my '89, tirerack has 'em untill I say it's a SPG (or an '89...something of that nature) :(
Evil fake 5 lug pattern, just want a winter rim set and a summer rim set.
I saw a set of 16" aero wheels on Ebay just the other day. I don't know if they'll fit an 89 SPG or not. Do you have Ronal wheels?

Sc
 

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Discussion Starter · #14 ·
Fetchitfido,

I made a mistake. The 16" Aero rims I saw are on the Nashville Craig's list (not Ebay) for $300 obo. The guy says he had them on a 90 900. I'd like to get them myself but I'm in over my head with my SPG project. Here's the link http://nashville.craigslist.org/car/466293067.html

Steve
 

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Shipping would probably be a bear. Thanks for the idea/link though, gives me an idea what fits again.
 
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