Thursday, September 4, 2008
Q&A: Binding Mavic Ksyrium cassette
Q: Jim - The cassette on my Mavic Ksyrium rear wheel is binding. I first noticed this by seeing that if I spun the rear wheel by hand, every now and then the chain would suddenly start being driven by the rear wheel and the pedals would turn - almost like on a fixie bike with only one gear and no coasting feature. At first it only did this once in a while, but now it's binding all the time and when I am riding the cassette tries to turn with the wheel and this creates slack in the chain and I bet additional friction at the wheel that's slowing me down! Not good on what are supposed to be my fast wheels. What do you think is wrong, and do I have to return my wheel to Mavic for service, or is this something I can fix myself?
Thanks for any help you can provide,
A: Hi Lloyd,
The likely problem is lack of lubrication, or some grease that has gotten congealed and is now sticky instead of slippery, right where the cassette attaches to the hub. There are cartridge sealed bearings inside and also seals. All these things need to be nicely lubed for the cassette to spin freely and not bind or drive the chain forward. I recommend visiting Mavic's tech website at http://www.tech-mavic.com/, login "mavic-com" and password "dealer" (do not include the quote marks)
Here you'll find manuals for all Mavic products going back years, and instructions for your specific wheel (like the diagram above). Assuming you have a few basic tools (you'll probably need a 5 and 10mm Allen wrench and a way to hold the axle, such as an axle vise - or home-made version) and a little mechanical ability you should be able to fix this problem yourself by following the directions.
For a sticky cassette, you would disassemble the hub by removing the axle with Allen wrenches and then carefully pulling off the cassette (don't drop/lose the pawl springs!). This reveals the bearings and seals and you can check the grease inside and clean and lube as necessary. Use a light and safe oil (it mustn't attack rubber or plastic) on any seals because if they're dry they can cause the binding. Then reassemble the hub and you should be good to go. Or, if you'd rather let a professional handle it, any shop that sells Mavic wheels should be able to service yours for a reasonable fee.
Happy hub and cassette repairing!