GS1000 1978 smaller rear brake

[Highway star]

Apologies if this subject has been discussed previously but I am looking to change the huge rear brake caliper to something much smaller like a brembo or similar. I appreciate I will also require a different disc and bracket and probably spacers. Has anyone done this modification.Or alternatively an underslung conversion , but unsure how this works without the torque arm

[salty_monk]

It can be done but it needs a new caliper hanger CNC cut. I did it on a GS750ES. It's not particularly simple because the stock cast caliper hanger is a pretty complicated beast. It's curved and hollowed out.

Additionally most modern calipers are meant for a smaller rotor than our stock one - the opposite problem to the front!

If you used a slimmer caliper you may be able to change the spacer pack to allow you to build your caliper hanger on a flat sheet but you'd also have to re-space the stock rotor. That's basically what I did but I was using a more modern wheelset & rotor. Needed a custom torque arm too.

To go underslung you need to either weld or clamp something to the swingarm and get a caliper with something to bolt to that. A lot of modern ones slide in a track on the swingarm to stop them rotating. That won't work with our setup obviously.

All-in the stock rear brake setup on the GS's is pretty good. It's an opposed piston caliper & about equivalent to anything more modern in power & modulation.

[Highway star]

Thanks for all the information, it does sound a bit of a task.

[Highway star]

Decided to stick with original caliper but trim20211204_141854.jpgmed away unnecessary metal to stream line it and did same with bracket.

[steve murdoch]

That looks great!
I also see safety wire holes? Are you heading to the track?

[Highway star]

That looks great!
I also see safety wire holes? Are you heading to the track?

Thanks, no track riding planned I just think they look good

[salty_monk]

Looks great