Removing Brake Disc

[Alicat]

I want to change the front brake disc on my cross bike. Should be easy, it is a Shimano centre lock fixing no problem, I have the correct tool, but I can’t get it onto the locking ring as there is not enough clearance between the ring and the axle. Any ideas? I can’t see how to get the axle out either,

[frisbee]

You need to work out how to get the axle or end cap out. I had to change end cap’s on a new wheel and i had to drift the fitted cap out of the wheel. In my case it was obvious as I had several extra end caps.

It looks like they fitted the brake disc first. It should have an external, bottom bracket style, brake disc locking ring.

Edited by frisbee on Thursday 15th June 03:57

[GravelBen]

Hard to tell from that photo, but is the outside of the lockring toothed as well for a different tool?

My Shimano centrelock MTB discs take a BB tool around the outside edge of the lockring, though some look like a cassette style tool would fit the inside as well.

Edited by GravelBen on Thursday 15th June 05:00

[dontlookdown]

What a pain. That is an annoyingly dim combo of parts, they should have used a 6 bolt hub rather than centrelock if the clearance is so tight.

You could try a small punch on a lockring tooth and tap it round, or if there is room, grip the outside of the ring with mole grips.

Might be an idea to use a 6 bolt to centrelock adaptor on reassembly so you don't have to do it every time you want to take the disc off. Although you would need to buy 6 bolt discs to match.

[wpa1975]

Shimano offers internal and external lockring type brake discs.

With the hub you have you need an external one to save removing the end cap each time.

I believe you can purchase the lockrings separately.

[Alicat]

Thanks all for your replies.

There are no end caps fitted. The tube sticking out of the hub runs right through the hub. I have the Mavic exploded diagram, which shows this, but not how to get it out.

Totally agree, a real awful mix of components and when I have it stripped I will replace with a ring with outer serrations.

[emicen]

Alicat said:

Thanks all for your replies.

There are no end caps fitted. The tube sticking out of the hub runs right through the hub. I have the Mavic exploded diagram, which shows this, but not how to get it out.

Totally agree, a real awful mix of components and when I have it stripped I will replace with a ring with outer serrations.

If you’re going to replace the ring anyways, I would just use a punch or flat head screwdriver plus suitable percussion instrument. Wouldn’t be great for re-fitting but you’re not going to need to worry about that.

Once the ring and disc are out, reckon stripping the hub will be a lot easier.

[gp1699]

I have a stans hub that looks very similar to that. It has the two notches on the end of the axle and it unscrews. Have you tried to see if it’s a screw end?

[Alicat]

I think you may be right, there are notches on both ends of the axle. The Mavic diagram doesn't show them.

I did give it a little try, but it didn't move and I didn't want to damage anything until I was sure.

[ScubaBiker]

Are you using a lockring tool that is a few years old? The newer lockring tools should have a thinner sidewall to allow access to these sort of situation.

I have an old an old Park FR5 lockring tool and that generally won't fit lockrings on thru axles. The newer version from Park, the FR5.2, has been modified to allow access. I now use a BBB tool with a built in handle and haven't had an issue with it yet.

[Alicat]

ScubaBiker said:

Are you using a lockring tool that is a few years old? The newer lockring tools should have a thinner sidewall to allow access to these sort of situation.

I have an old an old Park FR5 lockring tool and that generally won't fit lockrings on thru axles. The newer version from Park, the FR5.2, has been modified to allow access. I now use a BBB tool with a built in handle and haven't had an issue with it yet.

I had another look at the locking and tool. I think you are right as my tool is years old, I have a new tool on order. Fingers crossed.

[Alicat]

Thanks all for your help. I now have the disc off.

The new tool was still too large to fit. So tried other options.

The axle is indeed not a single tube and the end of the axle within the centre lock unscrews. Only the very end comes off, and just enough to get the tool in. It wasn’t that tight so putting and an Allen key across the slot on each end of the axle was enough to unscrew it.