I have Tyrepal units on my caravan and, prompted by your correspondents' comments was wary of the effects of winter towing. Some weeks after a foul-weather salty mid-winter tow returning from Holland, I encountered the bi-metal corrosion others had experienced, and took it up with Tyrepal. We had telephone conversations and email exchanges about various types of grease inhibitors, in which I suggested that silicone grease might be a preferable option. They took back my units, and after examination and testing, have replaced the retaining rings.

They were fully cooperative throughout, happy to have a dialogue about the conditions and problems encountered and helpful in resolving the matter. They have also since updated the FAQ section of their web site and are now recommending silicone grease. I regard this as a good outcome for all concerned; we have all learned something - and your column was highly instrumental in the progress made. I hope your readers will now feel more relaxed about Tyrepal. I can (now) recommending the product.