1978 GS550 Upgrade Rear drum to disc

[Guest]

I recently acquired a 1978 GS550. It was kept in storage, so I'm in the midst doing the usual revival maintenance. I was wondering, has anyone upgraded the rear drum brake to a disc brake on these? I know the E model had a rear disc, but alloy wheels. I prefer the spoked look, and want to avoid swapping both wheels.

Is there any way to have a rear spoked wheel with a disc brake on this bike? Has anyone here done it?

[hampshirehog]

You can replace everything with parts from a spoked wheel 750. Having said that the 550 had a decent rear drum on it and in my opinion you're better off keeping what you've got.

[dorkburger]

Depends on your intent. If it’s for better braking, you’re better off upgrading the front brakes as the rear does little work compared to the front - see Salty Monks twin pot caliper upgrade here for a relatively simple upgrade.

[Isoparmesan]

You know, that’s actually a really good point. I’ve only ridden it around twice, but the rear brake did feel like it had a good amount of bite. I think I just had it in my head that DRUM=BAD. I did also notice that the front didn’t have a ton of stopping power, but I was going to bleed/replace the brake fluid before assessing it. Front pads look good.

Are the the front brakes on these bikes just not great?

[Rob S.]

Are the the front brakes on these bikes just not great?

It's a 1978 bike. My 1982 twin front disks work fine, but they can't hold a candle to my friend's 2004 Concours. Time marches on, technology improves.

[GSXR7ED]

These bikes hold their own in the front brake department. At least for my riding style/habits...and I have a single disk on my 750T.

Upgrading to braided lines and doing a complete overhaul of the master cylinder and calipers improves brake power.

I would imagine a 550 is substantially lighter than my bike. It all depends on how far you push these vintage bikes.

My two cents...

Ed

[Grimly]

For sure, the earlier small round hockey-puck brake pads on the earlier bikes weren't great, but when freshly overhauled they can be OK - I don't have fond memories of those calipers at all.
Not so sure about yours, but many of the 78 /79 bikes can be fitted with the later, larger calipers as a straight-fit bolt-on mod. Doing this in conjunction with new lines, decent modern pads, and a rebuilt or replacement master cylinder can work miracles.
My 850 is a porky lump, but overhauled calipers and Carbon Lorraine pads made a world of difference to it. They need proper bedding-in though.
Handy thing about the later calipers is that aftermarket pad makers brought out pads for them and there are some bargains to be had, as they're not selling well at all these days. I think I paid about 20 quid for four sets of CL pads - and they'll last me a long time.

[frankenwabbit]

I think the gs750 with the rear spoked wheels had a rear disc. you'd have to get that at the very least...the bearings, axles and spacers may be different.

[salty_monk]

The worst thing about a drum is servicing it... in reality the front brakes do the lions share of the work (especially if they are good ones) and you should virtually never have to service the rear once it's overhauled the first time.

There is an upgrade for both single or dual front brakes. If you are starting with brakes that need a full service it's often no more expensive than a full rebuild (as you can still find calipers and master cylinders cheaply that only need a clean up).

The brakes used are actually the same ones as that 2004 Concourse mentioned above!

Let me know if I can help. I do have some bracket sets on my shelf.