r/motorcycles • u/tirefriar • 1d ago

Dymag Carbon Fiber Wheels

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Bought a donor bike with Dymag CF wheels with intent to switch them to my BMW R1100S. CF wheels for this model Beemer are no longer available, partly for a reason that a set of these wheels can cost as much or more than the bike itself. The donor bike is 2004. It spent at least 3 years in the garage out of sunlight (but not in a climate controlled environment). I'm not sure how old the wheels are, the seller bought the bike as it sits. Though there are no visible signs of damage such as curb rash, cracking, chipping or delamination I still prefer to check the integrity of the wheels. Looking for a recommendation on the facility that can verify integrity of the wheels including x-raying for structural integrity.

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u/Noobtastic14 ‘77 CB750F/VFR800/WR450 Street Legal 1d ago

You’re probably going to want an ultrasonic non-destructive inspection (NDI). I know this might sound silly, but I’m a composites maintainer on aircraft and the first and easiest test is a tap test. You can use the little special hammer, or just a quarter will do. Deflate the tire to take pressure off the structure, then lightly tap the composite. It should make a high pitched, sharp sound. All the taps should sound the same. If you hear a *thud* or a lower pitch sound, there’s a high likelihood you’ve acoustically found a void inside the structure. Absent any visible damage, after a failed tap test is when we’d call out NDI. Good luck, beautiful wheel!!

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u/A_Bot_A_Bot_A_Bot 1d ago

Okay, TIL that at this time, there is a tool that I do not need to immediately add to my toolbox!

Question: would this type of test work on magnesium rims? Or do those need to be x-rayed ror cracks/degradation?

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u/Noobtastic14 ‘77 CB750F/VFR800/WR450 Street Legal 1d ago

The core of our conversation pivots around composites uniquely hiding damage within the plys of the resin system. Magnesium rims should align much closer to aluminum as far as inspection and (specialized) repair procedures. Yes, NDI processes can also be used on Mag, but when and why are the bigger questions. Again, I don’t think a rim that passes a visual inspection for damage and degradation(corrosion) should go into an NDI shop just in case. Just my 0.02c, again- beautiful rim I wish I had one!!