Good jockey wheels

[midlandsgrimpeur]

The damage is because of contamination, the contamination is due to crap sticking to the oil. The remedy is to clean and re-oil your drivetrain regularly or look at waxing as an alternative.

You can potentially upgrade those bushed wheels to higher-end ones with ball bearings (as per this post) although you'd want to check the dims and tooth count are compatible..

Ball bearings certainly last longer than bushings IME. Have to say, Dura Ace on my summer bike have been the best I have used. Got about 50,000km on mine and the bearings are still smooth and well sealed and the wheels themselves in excellent condition. Personally I'd pay the £30-40 again for performance and longevity.