CromodoraCD58 center widend by corrosion
- Thread starter Mxgrds
- Start date
Dan Sarandrea (Phila)
Waitin' On Parts...
To my knowledge, the CD58 wheel is a hub-centric wheel. Hub-centric means that it uses the precision fit of the big center hole in the wheel against the lip on the axle hub to precisely center the wheel on the hub as it is bolted to the hub. If this fit is sloppy or loose due to damage, wear, corrosion, etc, then it is impossible to precisely center the wheel on the hub, and the result is what feels like an out-of-balance wheel and tire.
When I was looking for CD58 wheels to put on my car, I initially bought a set of four from Great Britain but upon receipt found that really only one of the four was serviceable, due to the same severe corrosion. Cromodora's Elektron magnesium wheels are high maintenance items that do NOT stand up to neglect---they cannot be treated like a steel wheel. Wherever the underlying metal is in contact with another metal, severe corrosion will happen if the protective paint finish is chipped or worn and not repaired. Most of this kind of corrosion will happen on the rear mounting face of the wheel, the center bore, and the outer lip where wheel weights are clipped.
If the corrosion has eaten away enough material to loosen the fit between the wheel and hub to the point where you can see radial movement, then it is going to be hard to get the wheel centered on the hub, therefore increasing the chance of off-center mounting and increasing the chance of an out-of-round condition, which would cause vibration at speed.
When I was looking for CD58 wheels to put on my car, I initially bought a set of four from Great Britain but upon receipt found that really only one of the four was serviceable, due to the same severe corrosion. Cromodora's Elektron magnesium wheels are high maintenance items that do NOT stand up to neglect---they cannot be treated like a steel wheel. Wherever the underlying metal is in contact with another metal, severe corrosion will happen if the protective paint finish is chipped or worn and not repaired. Most of this kind of corrosion will happen on the rear mounting face of the wheel, the center bore, and the outer lip where wheel weights are clipped.
If the corrosion has eaten away enough material to loosen the fit between the wheel and hub to the point where you can see radial movement, then it is going to be hard to get the wheel centered on the hub, therefore increasing the chance of off-center mounting and increasing the chance of an out-of-round condition, which would cause vibration at speed.
Options:
1. To my knowledge, although they were never offered in the US, CD58s were a common optional wheel in Europe, there should still be some good used ones around.Replace the wheel with one that has no corrosion in that area; inspect the rest of the wheels for the same condition. If others have chipped or worn or missing paint in this area, refinish to prevent future issues.
2. Have a good machine shop enlarge the center bore beyond the corroded surface to a size that matches an available hub centric ring. So you would need to purchase a hub centric ring that has an inner bore to match the hub (58.1mm) and an outer diameter to match the newly bored out center hole in the CD58. Here is a website that sells a wide range of hub centric ring sizes: http://www.hubcentric-rings.com/why_hub_centric_rings/?confirm-international=true
So if the machine shop needed to enlarge the center hole to 60.1mm to clean it up, you would need these rings: http://www.hubcentric-rings.com/size-60.1-58.1/
Or, if they had to enlarge the hole to 63.4mm to clean it up, you would need these rings: http://www.hubcentric-rings.com/size-60.1-58.1/
etc etc
3. Take to a wheel repair shop to see if there is a specialist solution for the problem--maybe they have a way to add back corroded material?
4. In any case, it would be good preventive maintenance to remove all wheels, thoroughly wire brush the hub-to-wheel mating surfaces and lips of the hubs, and spray with a good rust-preventive paint. That should help to reduce future dissimilar metal-to-metal corrosion.
1. To my knowledge, although they were never offered in the US, CD58s were a common optional wheel in Europe, there should still be some good used ones around.Replace the wheel with one that has no corrosion in that area; inspect the rest of the wheels for the same condition. If others have chipped or worn or missing paint in this area, refinish to prevent future issues.
2. Have a good machine shop enlarge the center bore beyond the corroded surface to a size that matches an available hub centric ring. So you would need to purchase a hub centric ring that has an inner bore to match the hub (58.1mm) and an outer diameter to match the newly bored out center hole in the CD58. Here is a website that sells a wide range of hub centric ring sizes: http://www.hubcentric-rings.com/why_hub_centric_rings/?confirm-international=true
So if the machine shop needed to enlarge the center hole to 60.1mm to clean it up, you would need these rings: http://www.hubcentric-rings.com/size-60.1-58.1/
Or, if they had to enlarge the hole to 63.4mm to clean it up, you would need these rings: http://www.hubcentric-rings.com/size-60.1-58.1/
etc etc
3. Take to a wheel repair shop to see if there is a specialist solution for the problem--maybe they have a way to add back corroded material?
4. In any case, it would be good preventive maintenance to remove all wheels, thoroughly wire brush the hub-to-wheel mating surfaces and lips of the hubs, and spray with a good rust-preventive paint. That should help to reduce future dissimilar metal-to-metal corrosion.
Last edited:
Mxgrds
True Classic
Thanks fot the advice. Although Cd58 rims are easy to obtain, these are H2 type fot tubeless. Quite rare. Today I spoke a machine shop that might help me. The can enlarge the hole and make an aluminium centre ring as needed. Question is, will aluminium react with magnesium? Will a plastic standard centre ring be better?
Just based on numbers I quickly looked up (you want as close to 0V as possible to avoid corrosion):
The anodic index between Magnesium Alloy and Aluminum is about 0.8V.
The anodic index between Magnesium Alloy and Iron is about 1.0V.
Aluminium would be slightly better than the Steel/Iron hub, but it would still be very corrosive. Plastic would be best. Unfortunately, if you were bent on using metal, you best bet from a corrosion perspective would be beryllium . . .
The anodic index between Magnesium Alloy and Aluminum is about 0.8V.
The anodic index between Magnesium Alloy and Iron is about 1.0V.
Aluminium would be slightly better than the Steel/Iron hub, but it would still be very corrosive. Plastic would be best. Unfortunately, if you were bent on using metal, you best bet from a corrosion perspective would be beryllium . . .
dllubin
Don
Beryllium dust is pretty toxic. Also not cheap.
And if you are on the NSEA Protector, regardless of toxicity, a beryllium sphere is essential.
(Sorry, aarpcard said "beryllium", which is a trigger word for Galaxy Quest fans)Dan Sarandrea (Phila)
Waitin' On Parts...
For that mounting surface, I would suggest wire brushing, priming with a primer specifically for magnesium, then a topcoat. Then do the same for the hub mounting surfaces on the suspension. Then do the same for the remaining three wheels and hubs.
Dan Sarandrea (Phila)
Waitin' On Parts...
I had my CD58s powercoated and love it. They are sooooo easy to clean with the smooth surface. The only possible drawback is that the blasting due to abrasion, and powdercoating process due to its thickness, tends to soften the edges of the lettering cast into the wheels here and here. But I think it's an acceptable trade-off.