Brake Pad Thickness

[Bonneville]

Hello all,

I bought a set of replacement pads for the Z550 (A1, same calipers as Z1R and Z650) and they are thicker than the originals. The outer pad also has a depression cut into it where the piston sits and has no metal backing plate. Reading up on this, there are 2 listed pads for these calipers EBC FA033 (thick, no backing plate) and FA073 (thin, with backing plate). Z-Power list a pad for all models that looks like the thicker one I have bought. One of the EBC configurators list both for the same caliper...
Question is, what is going on here? I'm not bothered about the thickness as the piston goes back far enough to accomodate but the thicker pad has more surface area and will be touching bits of the disc that have never met a pad before (and are a different height as a result).

Thanks,

[walshyco]

I may be wrong but I think there are two different thickness of pads depending on wether you have twin discs (thinner discs) Someone more knowledgable may give you more info.

[z1bman]

according to my EBC manual the correct pads should be FA073. FA033 doesn't list the z550 as the correct pads

[compo z1r]

even old 302's don't list as 550

[Bonneville]

Excellent information, thanks. The first 550 had the same front end as the 400j but only for 1 year (the A1). The Z-Power listing looks like this:-

http://www.z-power.co.uk/z400500550/front-disc-pads-fa33

It shows the 550 in this list as well as Z650, Z1000A etc. This listing mentions the thickness and suggests either 73 or 33 'for a thicker pad':-

https://www.z1enterprises.com/brake-pads-ebc-fa73-kz900-1000-kz650-750-front.html

I wouldn't care about the thickness but the size of the surface area is different on my old pads. Here's a full cross reference listing both EBC 73 and 33 and all the bikes they supposedly fit:

http://www.rawpowermotorcycles.co.uk/armstrong-gg-performance-brake-pads-fa033-fa073-c2x14538522

I've now found a further set with chamfered edges that look the same as the ones in the factory manual. That's 3 sets for 1 caliper!

[ADRIAN H]

Depends on disc thickness. Twin discs tend to be around 4.5mm thick. Single disc 6.5mm thick.

[Bonneville]

Yes, the disk size would explain the thickness difference. The surface area, I think, is down to manufacturers. The pad I put in there after the rebuild was an Armstrong and these have a steel backing plate on the outer pad as well as the usual plate with screw thread for the inner pad.
This style also seems to be used by Kyoto. I've no issue with that but the friction area is smaller (there is a 1-2mm inset from the backing plate to the friction material all round). This now means grinding the disc or waiting for the ridge to cut a ledge in the new pads.