Are chrome wheels more fragile?

[davidwj95 167]

The only wheels I've ever broken have been the chrome type, is there something in the manufacturing process that makes them more brittle or have i just had bad luck with them?

I want some m chassis beetle style wheels for a project but as it will be raced i need them to be fairly strong.  I'm wondering if the type used on the mini lunchbox would be less brittle. I'd need to paint them unless anyone knows if they are made in any other colour other than chrome or yellow.

 

Thanks

[sosidge 669]

Tamiya chrome wheels are the exact same material as their standard wheels, they just go through a chrome plating process on the surface. Strength is the same for both.

[alvinlwh 7226]

That is right. If you build static model, you will find that the chromed parts are more brittle than unchromed parts. 

[Kowalski86 4270]

I remember the body mounts on the Midnight Pumpkin/Lunchbox being very brittle, and they were chrome. It's the same ABS material but the chrome process seems to speed up their brittleness.

[NUFCRc 171]

21 minutes ago, Kowalski86 said:

I remember the body mounts on the Midnight Pumpkin/Lunchbox being very brittle, and they were chrome. It's the same ABS material but the chrome process seems to speed up their brittleness.

They are. I went through 3 sets before I upgraded them to aluminium ones. 

[ad456 468]

Here’s a business that does electroplating and states it makes ABS brittle

https://www.borough.co.uk/electroplating-process/#:~:text=The plating process effectively bonds,Plating ABS makes it brittle.

[davidwj95 167]

Thanks for the replies, I found that the 2cv rally and polycarbonate lowride pumpkin use this style of wheel in white so I'll go with them.

[Superluminal 3895]

How did you get the grey outer rim so cleanly painted? Did you mask off the chrome centre? Looks great - i have the same set of wheels for a project that I wanted to paint the same way

[davidwj95 167]

24 minutes ago, Superluminal said:

How did you get the grey outer rim so cleanly painted? Did you mask off the chrome centre? Looks great - i have the same set of wheels for a project that I wanted to paint the same way

Thanks. Yes, I masked off the centre, push the tape down nice and tight using a finger nail to get the tape to follow the shape. then cut round the hub cap part with a sharp knife.  I think that wheel was core RC shark grey polycarbonate paint.

[Kowalski86 4270]

59 minutes ago, davidwj95 said:

Thanks for the replies, I found that the 2cv rally and polycarbonate lowride pumpkin use this style of wheel in white so I'll go with them.

You can always buy those, then spray them a metallic silver. It's not quite chrome but they won't be brittle.

[alvinlwh 7226]

1 hour ago, Kowalski86 said:

You can always buy those, then spray them a metallic silver. It's not quite chrome but they won't be brittle.

Or Alclad II chrome. 

[El Gecko 1518]

In my experience, yes chrome wheels are more brittle. My example is Blackfoot wheels. My original yellow rears are still going, and they have not lived an easy life, but they have never shown any signs of weakness. By comparison, probably half of my CCP chrome wheels (both fronts and rears) have a chip in the rim. The only other wheel that ever chipped like that was an old Losi, but it was riding right on the rim for a minute, on tarmac, when the foam tire disintegrated.

[Mokei Kagaku 2934]

I don't have much knowledge about plastics myself, but I work for an automotive supplier which has a division specialized on plastic parts. A couple of years ago, I got the opportunity to talk with one of our plant managers, who is regarded as the company's foremost expert on plastic molding (among about 65.000 employees).

One of the things I asked him about was the brittleness of chromed plastic. He replied that the two strongest contributors to brittleness of chromed plastic parts is the etching of the surface that takes place during the chroming process, and more important, the "straight jacket" effect (his actual words). The chrome isn't elastic and thus prevents the parts from flexing following an impact, thereby concentrating the (temporary) deformation of the part to a smaller area, causing higher stress than for an otherwise identical unchromed part.

[Saito2 7650]

Interesting info on the reduction in flexibility for a plated plastic part. Makes sense. I always assumed it was just the etch process. My experiences mirror (pun?) others here as well. I've broken the bearing centers out of two sets of Monster Beetle front wheels over the decades but never a Blackfoot wheel. This time around I might just puts B-foot wheels on the ol' Monster Beetle (which will remind me of the Monster Beetle Jr. unless I spray them gold).

[xjcpx 6]

On 10/7/2024 at 4:34 PM, Mokei Kagaku said:

One of the things I asked him about was the brittleness of chromed plastic. He replied that the two strongest contributors to brittleness of chromed plastic parts is the etching of the surface that takes place during the chroming process, and more important, the "straight jacket" effect (his actual words). The chrome isn't elastic and thus prevents the parts from flexing following an impact, thereby concentrating the (temporary) deformation of the part to a smaller area, causing higher stress than for an otherwise identical unchromed part.

Makes sense if you think that chrome is used as a surface finish on softer metals not only for its look or to prevent oxydation but also for its hardness
I believe it's one of the hardest metals around with a 8.5 value and this make the coating durable and resistant to abrasion, but it's very brittle in itself and paired with a waaay softer material such as plastic... might help starting cracks in it.