CK R45 hubs..slow?..

[ls1togo]

I recently bought a used (2013) set of Zipp 303's with Chris King R45 hubs. The original owner claimed to have raced and maintained them regularly in the recommended manner. I also lubed the ring gear and bearings and adjusted them (twice!) They spin nice and round in my truing stand, but on my bikes they seem slow..
Maybe it's just my butt feel, but comparatively, on two different bikes, they are slower than my Mavic R-Sys wheels (2009) even though they are 4 oz. lighter.
They are mounted with Vittoria tubs (elites) and the R-Sys are Vittoria clincher Pave's...both 25mm.
Do you think it's time for a bearing change?...or are CK just slower?

[kramnnim]

Lots of drag in the freehub when coasting

[Black Dog]

They are not slower. If they roll nicely on the stand they roll nicely on the road. Bearing drag on hubs is so small to be imperceptible and the difference between bearings of different hubs would be very very small. You are noticing other things such as difference in the tires or perhaps the new wheels give less feedback coppered to the very stiff r-sys. People perceive excessive feedback (buzz) as speed, when in fact, it is slower. That is why lower pressures on non-smooth surfaces are faster but 'feel' slower.

[R3awak3n]

agreed, doubt its the hubs that is slowing you down. Tires would have way more to do with that and even then, I think this might be in your head

[David Kirk]

Try installing the rear wheel into the frame with the chain not on the cassette and make sure that the QR is tight as you would use it on the road. Put the bike in the stand (or just hold it off the floor) and give the rear wheel a spin.

Does it spin freely and come to a very gradual stop only after reversing directions a few times? It should. Or does it spin a short time and come to a sudden stop without reversing direction?

You should also check the front the same way....clamped tightly into the fork.

dave

[PNW]

I had the same feeling with my HED C2/R45s...just felt sluggish to me and they had been serviced properly, etc.

I ride Shamal Ultra’s now and feel much faster on them. Honestly, I ride without a computer so couldn’t tell you if I really am faster but the Shamal’s take the cake for me.

[ls1togo]

Try installing the rear wheel into the frame with the chain not on the cassette and make sure that the QR is tight as you would use it on the road. Put the bike in the stand (or just hold it off the floor) and give the rear wheel a spin.

Does it spin freely and come to a very gradual stop only after reversing directions a few times? It should. Or does it spin a short time and come to a sudden stop without reversing direction?

You should also check the front the same way....clamped tightly into the fork.

dave

Hmmm...the front reverses for a quarter turn..maybe twice before coming to a stop...the rear also reverses for a quarter turn , again maybe twice before stopping...seems inadequate to me..maybe the preload adjusters are too tight?...it didn't seem so when installed...

[David Kirk]

Hmmm...the front reverses for a quarter turn..maybe twice before coming to a stop...the rear also reverses for a quarter turn , again maybe twice before stopping...seems inadequate to me..maybe the preload adjusters are too tight?...it didn't seem so when installed...

Try the same thing with the skewers just barely tight enough to keep the wheel from falling out and see what you get.

dave

[ls1togo]

Try the same thing with the skewers just barely tight enough to keep the wheel from falling out and see what you get.

dave

Aha!...very little, if any difference!...actually the front showed no change and the rear was slightly better than a quarter but no different in terms of ease of movement.

[Cat3roadracer]

I recently had a set built with Onyx hubs. Check those out. Amazing really.

[David Kirk]

Aha!...very little, if any difference!...actually the front showed no change and the rear was slightly better than a quarter but no different in terms of ease of movement.

Good deal. This test eliminates the chance that the frame and fork dropouts aren't parallel and concentric and creating a bending load on the axles. If the drops aren't right and the wheel is tightened in place it will often cause the bearings to bind.

When you hold the wheels by their axles and spin the wheels do they feel like they spin smoothly without and grabbing or binding? In other words do they feel smooth or do they have hitches or grabbing as the wheel comes to a stop.

dave

[Mark McM]

Hmmm...the front reverses for a quarter turn..maybe twice before coming to a stop...the rear also reverses for a quarter turn , again maybe twice before stopping...seems inadequate to me..maybe the preload adjusters are too tight?...it didn't seem so when installed...

If the wheel reverses a few times before stopping (when installed on the bike), then it shows that the drag is quite small - the force causing the oscillation comes from wheel imbalance, which is typically 10 grams or less. Given the much larger drag on the rest of the bike when riding, it is unlikely that the hub drag would even be detectable while riding. I'd look else where for the reason that these wheels feel slower.

[Cloozoe]

Slow hubs? If you can't feel significant friction (operative word "significant ") when turning them by hand, it's extremely doubtful.

[ls1togo]

Good deal. This test eliminates the chance that the frame and fork dropouts aren't parallel and concentric and creating a bending load on the axles. If the drops aren't right and the wheel is tightened in place it will often cause the bearings to bind.

When you hold the wheels by their axles and spin the wheels do they feel like they spin smoothly without and grabbing or binding? In other words do they feel smooth or do they have hitches or grabbing as the wheel comes to a stop.

dave

No hitching or dragging, if there is, it's virtually imperceptible...I tried different skewer clamping loads..snug but not too tight...I re-adusted the preload on both wheels, maybe I was a little too "within spec" ie; a 1/8 turn back...the rear seems markedly better, the front about the same..I'll re-mount the chain and give it a try...

[smead]

Mavic Ksyrium Elite and SL wheels I've used in the past always seemed to have a bit of drag unless preload was adjusted such that you could feel a little play. So that's how I adjusted them. OTOH, the amount of drag that slowed the wheel on the stand (i.e. no rock back and forth when stopped) when adjusted with no play was VERY unlikely to make a bit of difference on the road. I think it's in your head!

[11.4]

Your wheels sound fine. There isn't that much momentum in a slowly rotating wheel. The only hubs I've ever seen that will really swing back and forth as they come to a stop are loose-bearing hubs. And under load they don't actually perform any better than any other hub.

You can have tighter seals which slow the free spinning slightly. You can have a thicker grease. These are things that under load will disappear. New King hubs tend to feel a little stiffer in the hand to start with and that can condition your perception of how they ride; that stiffness does go away as they are ridden a while.

One can't really measure simply by riding a bike the difference in resistance from one pair or another, until one pair is significantly impaired, and you don't have that.

On the track we used to measure riders in precisely controlled events, using both sealed bearing hubs (e.g., Phil Wood track hubs) and loose bearing hubs (e.g., Dura Ace 7600). We'd lubricate the 7600's solely with machine oil -- no grease -- and they did a great job of psyching up the rider when we showed her/him the axles spinning and spinning and spinning, but if we simply put the rider on the bike, there was no performance enhancement.

There are rare issues with CK's (both Classics and R45s) where the bearing isn't sized precisely for the hub shell. The way CK does it is to have sealed bearings and hubs that are machined to a certain but not excruciating tolerance and then they measure both precisely and match the best bearing to the hub shell. It works well. If someone has replaced bearings and not measured carefully, one can end up with a bearing that is slack in the shell and tends to maintain some wobble or is slightly tight and the shell might be warped slightly due to trying to force in a bearing that is too tight for it. But in either case you don't typically get meaningful resistance occurring. If somebody serviced the bearings and really messed up the clips and the removable seals, again there might be a little more resistance but you seriously couldn't measure it on the bike, powermeter or otherwise.

Remember that how a bearing operates under load is completely different from how it spins loosely on a bike stand. I think you're fine. Just ride them and don't psych yourself out.