Drum brake hub size

[Rideanddive]

Hello, I am using what was sold as a 1985 gs550 rear wheel for a project and have hit a snag. The brake hub area on the wheel is approx 7.5 inches OD and the brake plates I find are approx 6.5 in OD. Can someone please advise what year had the larger brake so I can begin searching for the proper brake assembly. Thank you very much for the help.

[Big Rich]

Is it a mag wheel? I have a GR650 rear hub I can measure later tonight if it's any help.

[Rideanddive]

It is a mag wheel. 16x2.75. It is not the "star pattern" but has ribs that don't intersect. I will post a pic when I get home to help. It was purchased off eBay. I posted a question here earlier but responses were not really specific... I guess this is a "second generation" wheel. I have asked multiple sellers to measure the parts for me but only 2 have actually gotten back to me. I have purchased 2 brake hubs already, one listed as 1983 and one as 1985 both for gs550s but both were the same size....too small for my wheel so I'm hoping someone can identify what wheel I have so I can hopefully buy the right part this time. Thanks.

[Rideanddive]

Here is a picture of the measurement of the brake side of the wheel



Thanks again to anyone that can help. This has been quite a long
process to figure out.

[Steve]

By your description (can't tell from the picture), you do have the second-generation wheels.

The 750T had similar wheels and a drum brake, but were 17" wheels.

.

[Big Rich]

Yep, ya got me beat. A GR650 wheel is 2.5x16 and has a service limit around 160mm.

[Rideanddive]

What years comprise the second generation?

[Steve]

Started in '82 on the shafties, not all the chain-driven models got them the same year.

Here is an '81 650L:



Here is an '82 650L:


.

[Rideanddive]

thanks so much. This finally gives me something to go by. So I should search for 650l brake hubs. I've been searching for 550's of various years but only that model. That probably explains why I'm not coming up with anything.

[SVSooke]

Look at the rear brake in Steve's pic,it's a disc brake.I'm trying to think of any bikes with those wheels that has a drum rear.Only one I come up with is a GS450L,I'm not sure what size wheel they have cause I have no interest in L's

[Steve]

thanks so much. This finally gives me something to go by. So I should search for 650l brake hubs.

Sorry, the pictures were just to show the difference between 1st gen and 2nd gen wheels, not suggesting them (the 650L) as a source.

Besides, you need something with CHAIN drive, not shaft.

For a 2nd gen wheel with a drum brake that might be larger, look at the '82 750T:


.

[SVSooke]

Of course I could be wrong

[Steve]

Of course I could be wrong

No, you are not "wrong", just "not yet fully-informed".

.

[SVSooke]

More like I forgot how under braked that Suzuki made the 750T.If I recall correctly the T's had 17" rears,OP's wheel is 16".