Bought a new KHE Collapse chain that arrived today in the post a big thanks goes to TartyBikes, fitted it all succesfully. The downside is that when I pedal hard it keeps slipping off the rear cog, I think its where the cog is small. My friend uses one of these chains on a 18 - 16 tooth ratio and its fine (I wouldn't of thought a cog that is 1 tooth smaller would make a difference), so I found an old KMC Kool chain and it does the same slipping thing. the only chain that i've found that works well with that gear ratio is the reluctant halflink chain, which i snapped a few days ago so I don't want to go there again, I think the only way for me to solve this issue is go to the classic 18 - 16 ratio. I just wanted to be different and do what TartyBikes said on the website "Ideal for fine-tuning your gear ratio! Never before have 17T and 19T sprockets been readily available for stock riders, and 13T for mod bikes have always been hard to come by. So why not try 18:13 on your mod? Or 17:15 on your stock?" Has anybody else had this problem what did you do about it? Thanks in advance. Tom