Monday, February 20, 2006

Chris King Hubs

Last week I spent some time getting to grips with some maintenance on my 9 month old wheelset that originally Chaybo built me, Chris King ISO disc hubs on DT XR 4.1d rims. They've pretty much performed flawlessly with the only exceptions being a couple of early sessions nipping up loose spokes and the initial 600 miles-ish run in period ! The CK manufacturing tolerances are so high that you can expect a fair amount a initial drag but the pay off is that they remain super smooth. Recently I noticed that the freehub has been tight and causing the chain to fall down the cassette when you back pedal (e.g. lifting a pedal to start off) and then clunking back up when you begin cranking. Something needed to be done.

The CK website has an excellent technical section which have some of the best maintenance videos that I've ever seen. Along Chad's words of encouragement and wisdom it helped me crack on with popping these beauties open.

Maintenance on the front hub was easy as it only has the two rotational bearings to strip, flush, regrease and rebuild. You won't find any cheap sealed bearings here, they're stainless bearings and fully rebuildable using a snazzy snap-ring and seal. It's worth noting that the CK axle doesn't use tranditional threaded bar, cone and lock nut to tighten the bearings which needs mucho fiddling to get right. Instead the axle is a chunky, fixed length bar that means it always goes back in the right place everytime and is a doddle to adjust the bearing preload. Checkout the technical doco for more details.

The rear was a little more troublesome as I also got the draggy freehub to contend with. My first effort felt notchy and I doubt that'd fully cleaned the bearings and possibly even over tightened the bearings. The 2nd session had the rotational bearings running sweetly but the freehub was still very draggy. So apart it came for a 3rd time, where I diluted the freehub lube a little more, which seemed to do the trick. Back on the bike I found that the preload bearing needed an 1/8th turn to stop a wobble and it was job done.

I agree 100% with Chaybo in that these hubs really are a joy to work on. They're so well engineered that the task isn't hard work and my minor "troubles" were only due to my unfamiliarity with the gear. In use, the immediate pickup of the rear hub is divine and a major selling point and should go someway towards justifying the high cost.

The DT rims have also proved to be highly reliable with the only blemishes being a few battle scars from rocky visits to Wales. Throughout their first 1,300miles, they're still true and round and have never felt flexi. As they're kinda UST compatible (with a rim kit) I'd say that the rims are slightly larger than non-UST hoops 'cos getting tyres on/off is a right wrestle. I've a couple of UST kits in the garage waiting to try out their tubeless ability, so stay tuned.

Now lets see how they feel after a couple of rides...