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Ksyrium Freewheel(11 posts)

Ksyrium FreewheelGreyhound
Mar 31, 2002 3:49 PM
I just got some new ksyrium Sl's, and I noticed that when I have the bike in the stand, and I pedal backwards, the wheels spins backwards. This does not happen with my ultegra hub training wheels. I this just an issue of breaking in the hub? Any feedback would be greatly appreciated.

Seal and lube dragKerry
Mar 31, 2002 5:09 PM
Two things going on: the seal contact is sufficient to create the drag, and the lube (grease) is thick enough to create drag. Both drag components will decrease with time. The super short term fix is to take it all apart and lube with a thinner grease/don't coast. The longer term fix is not to worry about it, since the amount of energy lost here is tiny compared to the other forces (friction and wind drag) affecting the bike.
re: Ksyrium Freewheelmerckx56
Mar 31, 2002 5:11 PM
mavic freehubs are notoriously tight out of the box. try playing with the adjustment tool and seeing if you can loosen the hub a bit. mine are two years old and the rear still does what you are describing from time to time. i think the tolerances are so close that there is virtually zero error or room for error in the k's.
re: Ksyrium FreewheelGreyhound
Mar 31, 2002 9:58 PM
Wouldn't the hub tuning and freewheel/cassett body be seperate adjustments? I don't think that would help if I'm thinking of the right thing.

a thoughtJekyll
Apr 1, 2002 7:26 AM
Don't know if you have your spoke protector installed. When I first got my K's I installed the spoke protector that come with the wheels. The spoke protector is molded in a way (with an offset toward the spokes) that it was touching both the spokes and the cassette. This would create slight drag between cassette body and the wheel proper thus turning the wheel when pedaled backwards in a work stand. I found it annoying enough to just remove the spoke protector. That fixed things.
re: Ksyrium Freewheelmerckx56
Apr 1, 2002 7:28 AM
true, but the hub might be bound a liitle bit, thus creating that drag. try the adjustment on the non-drive side, just for giggles. the freehub can't be adjusted. it will loosen up over time though.
It Matters Not.grzy
Apr 1, 2002 11:13 AM
Sure there is some drag and it's more than maybe some other wheels - initially. As many have pointed out it's due to seals, being new, and also the design of the ratchet mechanism. However in the end it matters not. Here's why - it only comes into play when you are *not* pedaling. When you are pedaling the ratchet is engaged and there is no relative movement between it and the hub. But what about when you're not pedaling? Well, yeah, you're slowing down (that's why you're not pedaling - right?), but the amount of friction here is many orders of magnitude smaller than all the various sources of wind resistance.

My advice would be for you to leave things well enough alone - the Mavic folks know what they're doing and are intimately more familair with the design and mechanical issues. In any evnt the only real adjustment available to you is the bearing adjustment on the wheels. Trust me on this one - I've been running the K's for a couple years and have rebuilt various blown up Mavic hubs.
It Matters Not.VW
Apr 1, 2002 11:36 PM
Can't always pedal when going down a steep hill with lots of hair pin turns!

When I first got my Ksyrium, the drag was so bad that even the rear derailleurs spring couldn't keep the chain tensioned. The chain would completely sagged down and beated-up my chain stay when I stopped pedalling going downhill.

I thought the spoke protector was rubbing too hard on the spokes, so I lubricate the spoke protector. I didn't want to remove the protector and risk damaging my new wheel if the chain accidently fell-off. That improved it, but the chain was still fairly slacked while coasting downhill.

After about a hundred miles or so, the drag went away. I'm still not sure what was dragging (spoke protector? seal?).
It Matters Not.grzy
Apr 2, 2002 9:57 AM
It's the spoke protector - I've never seen anyone use one of these. The thing is too thick and is like a slipping clutch between the wheel and the cogset. If you set you limit screws correctly you won't need it - unless you try and ride your bike after the der. or hanger has been bent in.

So you have a steep hill with lots of hairpin turns you're riding the brakes anyway. No one is going to go through the corners faster than you simply b/c you're running Ksyriums - it's all skill and technique.
It Matters Not.VW
Apr 2, 2002 2:26 PM
No, I wasn't worrying about losing speed, just the chain stay of my precious OCLV.
Less is more.grzy
Apr 2, 2002 7:05 PM
You take that spoke protector off and properly set you limit screw and you'll be fine. I'm willing to bet that the vast majority of Ksyrium owners are running without them based on my non-scientific observations.

BTW - spoke protectors are a Fred-badge, it's a lot like wearing a plastic pocket protector.