R100 GS Brake shoes

[LeeGP]

I am trying to decide whether or not to replace the shoes on a 91 GS. The existing ones (original ones, I think, as they are dated 9/90) still have about 3.5 mm of lining , which is fine according to the manual (it states a minimum of 1.5 mm). I am just wondering if it would be necessary or advantageous to change them, being that they are 22 years old. Any and all thoughts/experiences appreciated. Thanks Gary Lee in Tennessee

[ME 109]

If they are oil/grease free, a good scuffing with some 80 grit will have them as good as new. Maybe better than new as they will fit your drums perfectly. 3.5mm is heaps of meat.

[Major Softie]

Shoes do get a little harder with age, but it's unlikely new (stock) ones would perform much differently . . . except, as ME 109 points out, that the new ones wouldn't work as well until they'd worn in to fit as well as your old ones.

I wouldn't consider changing them until maybe 2 mm, and even then I'd only do it because I'd be afraid I might forget about it too long otherwise. If you have a better memory than me, run them right down to the minimum spec.

[Deleted User 72]

..... If you have a better memory than me, run them right down to the minimum spec.

Do you have a memory spec for him to shoot for?

Me, I don't have a spec of memory and my vision's so bad I'd prolly miss anyway.

[ontic]

I'd beg to differ,
From what I've read, and from looking at my own bikes, the brake shoes these bikes came with were very hard when they were new- ie a bit too hard and tended to wear out the drum rather than the pads. Add 22 years to the situation... things aren't getting any softer. I think the fact that the lining is still within spec pretty much shows where the wear is happening.

I'd look at the price difference between shoes/relining and a new rear hub or complete wheel, like I just had to buy for the G/S (cannot reline G/S hubs, hubs NLA, wheels also NLA, but I managed to find a new old stock one for $$$). They are not cheap! . My old rear G/S hub is close to wear limits (the hub is also a bit banged up and the rim dented), the shoes, original bmw ones, and nice and glazed, look pretty good! Plenty of meat left! I wouldn't be surprised if they were original too.

But, new aftermarket shoes are probably aren't the best answer anyway (fitment issues)- apparently the best bet is to get your old shoes relined with a nice new modern compound that will actually wear. Sure, you won't get another 22 years out of the lining, but you might just get another 22 years out of your hub if you have caught it in time, and your rear brake, which by all reports is rather lacking on the GS paralever rear end, might just improve a bit.
Being in the US, I've read it mentioned a few times but you have some easy options for re-lining your old shoes.
Just my two cents (all I've got left after buying a new G/S rear wheel )
YMMV.

[Major Softie]

Ontic, I know that applies to the stuff they were selling in the 70's (plus those shoes are now twice as old as Lee's), but I have not heard those same things about the brake shoes from the 90's.

[ontic]

Gday Major, you might be right about 70's compared to the 90's... though from what I can tell, I'd include the early 80's shoes in the hard stuff as well..
I just think that original shoes, over 20 years old, still within spec, are wearing the drum not the shoes, and unless repair of the drum or replacement of hub is easy, something should be done about it.

The problem with my G/S in this regard is that the rear wheel is unique (3 lug) and relatively rare- OK second-hand ones are still around in Germany occasionally for a gamble. Seems like I got one of the last new ones (30 year old stock) until someone figures out a solution.
I read recently that the 100GS rear wheel is now also NLA new- though I am not sure of the veracity of that statement. No doubt there are more of them in rotation than G/S rears, they are also pretty unique and fetch good money second hand.

Maybe Lee never adjusts his brake, hardly uses his rear brake, and while the shoes haven't worn, neither has the drum...? My G/S was completely different. Shoes look original. Old drum is worn down and the adjustment on the brake rod is screwed right in. With these same (assuming) 30-ish year old shoes, I test fit the new rear wheel and have to screw the brake adjustment all the way out, right to the end of the possible adjustment. That compound on the shoes has barely worn at all.

I bought a set of EBC aftermarket shoes before I knew about their negatives. The casting is pretty crude, not machined where it should be and doesn't fit right. I'll probably try to get my bmw shoes relined when the time comes, with a softer compound.

[electric_monk]

I recently changed the shoes on my 89GS even though the old ones had plenty of friction material left on them. Every time I have changed the wheels on the bike I have given the shoes a real good cleaning with a wire brush and it has never made any significant or lasting change to brake performance. The new shoes have made a very noticable difference, so I for one would recommend changing them.

[Major Softie]

What did you put on it, E.M.? Stock BMW, or something else?

[electric_monk]

I don't know for sure, I ordered them from Motorworks, so they could be either EBC or Ferodo