[mattwatkins]

Maintenance Questions

I've had my Mojo SL for a couple of months now. I rode a fifty mile cross-country endurance event in Wales two weeks ago (The Marin Rough Ride) and spent a couple of days in Dalby Forest last weekend (really good trail centre riding in Yorkshire). These two events have been responsible for a bit of wear, and I think it is time to thoroughly check the mechanical condition of various parts.

I've given the bike a good clean, inspected a few areas, and have a few questions...

My Chris King ISO hubs developed some lateral play and looseness in the bearings. The rear was quite noticeable, making audible metallic noises when shaken side-to-side. It needed significant adjustment. I reckon it's quite difficult to get at the pinch bolt without removing the rotor, and the bolt itself is steel and susceptible to rust. Anybody else think the design could be improved? I would be interested if anybody knows where I might be able to source a titanium replacement bolt for the clamp ring? After taking about five attempts to get the bearing pre-load adjustment right, swapping the wheel in and out of the frame, I think I've finally nailed it. It's running smoothly, with no play or binding.

The Chris King front wheel doesn't seem to have any bearing adjustment - is this correct? The play is barely noticeable at all, but I do think there's a bit of side to side movement. Within normal tolerances, perhaps?

This is my first set of disc brakes on a bike, and I'm not entirely sure how frequently the pads need to be replaced. I've been covering some serious mileage in typically British conditions over the past two months, and I think I may have chewed through the first set of pads already. I remember cooking them in Wales at one point, as there was quite a burning smell noticeable on a couple of occasions. The brakes are Avid Juicy Ultimates. Since the last ride, the bite point seems to be too close to the lever. The contact adjustment (at the lever) seems to make absolutely no difference to this. The initial lever movement also seems a bit sticky. Looking at the callipers, I'm pretty sure I've not got much pad material left. Does this sound like replacement time? How frequently do other users with these brakes find themselves replacing pads? Could anybody give me any pointers to the best replacement pads for UK conditions?

Also, I've got a Hope ceramic bottom bracket with XTR cranks. I frequently take the chain off to give it a clean and oil bath. With the chain removed, I notice that the cranks make a "papery" scraping noise when rotated. They've done this since I got the bike. Is this noise coming from the seals, the bearings, or have I got grit trapped between the components down there that needs to be removed?

I may have a few more questions to add to this thread later in the week, but that's it for now. All advice gratefully received!

- Matt

 

[derby]

By "British conditions" I'm guessing you mean wet and muddy. I've found the Marta SL rotors work best in mud for longer pad wear and braking power, consider going to a 180 in front if you are doing much hard braking the increase in power is huge. Their Galfer designed wave pattern pushes mud away from the pads and there are no holes drilled in the rotors to pack mud, and mud between the pads and rotor ruins power and rapidly grinds away pad and rotor life. I've also found these rotors have a little more power in the dry than other rotors using the same brakes and pads, I think due to more edge facing the pads. I put Galfer rotors on my motorcycle and also got more power changing no other parts of the brakes.

I don't have experience with King hubs or XTR cranks. But you could probably learn how to adjust the hubs by taking them apart and putting back together. I've read that King hubs require quarterly maintenance, they may have just broken in and loosened up more rapidly while near new. And maybe remove and replace the cranks and clean up and wipe some oil on the BB bearing seals, and if easy to access peal the outer BB seals off and pack with a little more light grease.

 

[Gregg K]

Chainrings. After a year and a half of riding there developed the slightest roughness down there. I'm meticulous with chains. So I was quite surprised when I bought the two bigger chainrings that by comparison, I had completely worn the originals to a pulp.

The reason it's important is that the drivetrain wears at the rate of the most worn part. So it's time for a cassette, too.


It sounds like you've got a nice situation. I sure would like another lifetime so I could ride all over the world.

 

[mattwatkins]

I changed the pads this weekend. The front brake is back to normal, but the lever action of the rear still isn't quite right. Maybe I need to bleed it?

- Matt

 

[derby]

I changed the pads this weekend. The front brake is back to normal, but the lever action of the rear still isn't quite right. Maybe I need to bleed it?

- Matt

Spin the rear wheel and if you see the rotor isn't true within the caliper and pads it could be pushing the pads back more than ideal and make the lever a long reach to tighten the pads tight to the rotor and feel like it has air in the system. You can bend the rotor back wearing dry gloves or a clean spanner (you are in England right? Otherwise "crescent wrench"). Don't touch the rotor with your hands a tiny bit of oil off your hands or dirty gloves can spoil a rotor and pads and cause brake squeal and loss of power.

If the rotor is close to true and the lever pumps up harder with repeated pumps there is air in the system. You'll need the tiny fittings - clear hose, catch bottle, and a syringe makes it easies to push fluid into the system. The special fitting at the master cylinder end is specific to the brake brand.

 

[Flyer]

CK hubs do require you to adjust both the front and rear hubs a few times during the first few hundred miles. I think it is a 2.5mm allen key that is needed. Mud/dust will cover up the tiny screw. It may require this tightening to be done 5-10 times in the first 100-200 mils and they settle in after that. You do not have to remove the rotor or the wheel- just reach in with that allen key after cleaning out the debris. I have the 20mm version but I'm quite sure the QR version has the same adjustment.

In wet conditions, avoid organic pads and go with sintered pads. They will last 20 times longer than organic pads. I have used up organic pads in 2-3 long wet rides. I believe that Avis and Formulas come stock with organic pads- switch those to sintered.

Take your BB off, lean it, regrease with Phil Wood or Hadley grease, and reinstall. If the grinding sound continues, your bearings may be shot.

If you get the rotors dirty, just wipe down with isopropyl alcohol and a clean cloth. You can also use earbuds/Qtips soaked in that stuff to clean hard to reach places near the hub/rotor junction.