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I recently had my bike (Focus Mares CX) serviced by my LBS, during which they replaced my wheels with a set of new Campagnolo Khamsin wheels. In the month since I had that done I've found it markedly harder to pedal; I'm suddenly struggling to get up hills on my commute that were fine before, despite also having switched from a 27t to a 28t largest sprocket, and I'm drifting back from my companions when we're freewheeling.

When I remove the wheels and hand-turn the axles, the front one rotates smoothly and freely, whereas the rear one rotates smoothly but viscously. There's a lot more resistance than I'd expect, and compared to my friends' bikes. In the past I've always had cup and cone hubs, so this sort of problem was usually down to an overly tight cone, but these hubs have cartridge bearings and I'm unfamiliar with them.

I'm finding the hub schematic (pdf) a bit difficult to get my head around. There's an endcap on the non-drive side that's secured with a pinch bolt, which is apparently used to take us slack if there's play in the axle, but loosening it has no effect. Is there another bolt that I could loosen? The new wheel sits much tighter in the frame than I'm used to, and I wonder could the LBS have tightened up something so much to get it in the frame that it's overloading the bearings?

  • Have you removed the wheel and tried spinning it while holding it? – Andrew Henle Mar 27 at 14:32
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    One month? I'd suggest that you take the bike back to your LBS and have them sort it out. If you try to fix it and it fails they will be able to say you did something wrong. – Carel Mar 27 at 14:37
  • @AndrewHenle I've done that, it spins and it doesn't deliver any knocks or bumps to my fingertips, but I'm not sure how else to use that to diagnose a problem. Like I say, rotating the axle by hand feels oddly thick. – Deditos Mar 27 at 15:40
  • @Carel Yeah, that's my inclination. It's something I noticed from the first ride out, but I thought I'd check here first before I go back the LBS with wrong expectations. – Deditos Mar 27 at 15:46
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Adjusting the bearing is quite easy although it's more than just unscrewing the 2.5mm hex-screw at the left side of the hub. Here's the link to an instruction sheet from Campagnolo.

https://www.campagnolo.com/media/files/035_68_Technical%20manual_wheels_adjustment_hub%20Campagnolo_12-12.pdf

While the PDF describes how to remove excessive play easing an axle that is too sticky goes the other way round with one small addition.

The steps are the following:

Untighten but don't remove the 2.5mm hex-screw that pinches the left cup.

Hold the right-side axle steady and turn the left anti-clockwise (to untension the load on the bearings) by 1/8 turn.

Check if the axle turns as desired. If it's still too tight repeat the previous step.

--While it's easy to tighten a bearing that has too much play, it may be tricky to loosen one that is too tight. A slight whack on the right axle stub with a rubber mallet is helpful. (Speaking from experience with Campa wheels!)

Check if you didn't put in excessive play.

Retighten the 2.5mm hex with a torque wrench @ 2.5Nm.

But as I suggested in a previous comment I'd take the bike to the dealer because the wheels are rather new and still under warranty. And do it quickly, an overtightened bearing is easily destroyed.

One more thing: new rear wheels may be a little bit 'stickier' than one might think good. It is often due to the fact that they have to bear more load and resist to the pull from the chain. A couple of hundreds of km is often required to have them running properly.

They do have a video showing the overhaul sequence: https://www.campagnolo.com/WW/en/Support/complete_revision_of_campagnolo_wheels_hub

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    Thanks, that's all useful info. I think from watching videos on youtube I may have misunderstood how the adjustment ring works. But it's also not clear from the Campy docs what version of the wheels I have. I'll take it back to the LBS in the first instance, for the reasons you mention, but it's useful to have some pointers for if I don't get any joy there. – Deditos Mar 27 at 23:36
  • @Deditos True, the accompanying Campy manuals are quite poor in that regard. Workshop pages in cycling magazines are a good source for this kind of information. – Carel Mar 31 at 16:11
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Take the wheels back and go back to cup and cone. They worked really well for over one hundred years and have the perfect cup angle for bicycle hubs.

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    I can't knock cup and cone, but there are plenty of good quality cartridge bearing wheels too, OP's rear wheel is not performing as it should be. Check @Carel 's answer for a really good demo of helping answer the OP questions so they can help themselves fix it if preferred, whilst still concluding that the wheels should be returned under warranty – Swifty Mar 27 at 17:12
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    Cup and Cone has its place, and used to be top tech, but progress has advanced and I doubt any new bike above a BSO grade has cup and cone any more. I'd not be suggesting that OP replaces their wheels with older ones or super cheap ones at this point. – Criggie Mar 28 at 8:00
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    @Criggie I don't know whether cup and cone bearings are really bad, but all Shimano Hubs (including the newest Dura Ace 9100 and XTR 9100) are cup and cone. – StefanS Mar 28 at 9:35
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    @StefanS anything can be done well and anything can also be done poorly. Advising to replace some campy wheels before attempting the tuning as per other answer, seems fiscally irresponsible. I'd have them if OP doesn't want them ! – Criggie Mar 28 at 10:41
  • Cup and cone bearings are the perfect design for the lateral forces that bicycles face when cornering plus sealed bearings have friction where the seals interface with the races. Next time you attend a professional bicycle race, observe what all of the participants are riding, it's cup and cone. – Mike the Bike yesterday

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