Disc Brake Aligning Tool.

[Lovacott]

I keep getting spammed on FB etc. with ads for a brake aligning tool which I never knew I needed?

When I fit a caliper, I put a bit of cereal packet on the disc, pull on the brakes and then tighten the mounts.

Apparently though, I should have been using this?

 

[T.M.H.N.E.T]

They're a handy gadget

 

[T4tomo]

Cereal packet is a bit blue collar, I used left over business cards 🤣

 

[C R]

Cereal packet is a bit blue collar, I used left over business cards 🤣

Business cards, how analogue

 

[fossyant]

I don't use any - hydraulic MTB brakes - pads run close to the disc.

 

[raleighnut]

I use a bit of Rizla packet.

 

[MrGrumpy]

Nae idea why you would need that tool. I normally leave the callipers slack then pull the lever, then tighten the bolts. Works for me ?!

 

[Deleted member 1258]

I use a bit of Rizla packet.

Blimey! Thats a blast from the past, setting the points with a Rizla fag paper.

 

[raleighnut]

Blimey! Thats a blast from the past, setting the points with a Rizla fag paper.

Only works with new points though or ones that have been 'filed' flat, once they're a bit pitted they tend to grip the paper for a while after they've opened.

 

[Ajax Bay]

In an urge to add facts to this 'people keep spamming me with a tool' thread:
Cereal packet cardboard = 15 thou (YCPMV)
Business card = 12 thou (average of 4)
A4 sheet of paper (80g/sm) = 5 thou
Shop receipt (Coop) = 2 thou (assume about the same as a Rizla paper, but I went into the bike sheds, not round the back, so haven't got access to a packet)

I haven't been able to find a specified clearance (likely it varies between models) - anyone know?
Satisfactory clearance will also depend on trueness of the disc.
I found advice that a 0.2mm feeler gauge was 'about right'. That's 8 thou.

 

[chriswoody]

Excuse me for being a bit dim here, but I thought disc brakes were self aligning?

When I pop new pads in I just need to gently ease the pistons back, then pop in the new pads. Pumping the lever a few times, then bedding in the pads sorts everything out and all's well with the world.

Obviously the above procedure is for hydraulic discs, so what's with this gizmo, is it a vital step I'm missing out on? Or is it for cable pulled discs?

 

[Lovacott]

I haven't been able to find a specified clearance (likely it varies between models) - anyone know?
Satisfactory clearance will also depend on trueness of the disc.
I found advice that a 0.2mm feeler gauge was 'about right'. That's 8 thou.

I don't use card to set a clearance.

I simply adjust inwards until there is contact and then I back out a smidge until they run freely.

To align the brakes, I pop in a bit of card either side of the disc and apply the brake with the caliper mounting bolts a bit loose and then tighten them.

I find disc brakes to be one of the easier things to maintain on a bike.

 

[Lovacott]

Excuse me for being a bit dim here, but I thought disc brakes were self aligning?
Obviously the above procedure is for hydraulic discs, so what's with this gizmo, is it a vital step I'm missing out on? Or is it for cable pulled discs?

I think the tool is to set the disc centrally in the caliper.

 

[T4tomo]

Excuse me for being a bit dim here, but I thought disc brakes were self aligning?

When I pop new pads in I just need to gently ease the pistons back, then pop in the new pads. Pumping the lever a few times, then bedding in the pads sorts everything out and all's well with the world.

Obviously the above procedure is for hydraulic discs, so what's with this gizmo, is it a vital step I'm missing out on? Or is it for cable pulled discs?

some of the one sided adjustment cable disc brakes needed a business card to set them up, i used to do on some Avid BB7s back in the day.

agree nothing needed for hydros.

the gizmo is not needed for anything at all ever, yet is heavily marketed on facebook.

 

[chriswoody]

Thanks @T4tomo and @Lovacott , that's a bit clearer now. It's always interesting to learn more about the mechanical aspects of various bits of the bike. However, this gadget sounds like a classic example of a solution looking for a problem.