Rear Wheel Shaft / Brake Caliper Bracket Diameter Question

[Neveragain55]

Hi Gang,

I've run into a semi-complicated issue regarding my (rear brake caliper hanger / rear wheel shaft) fitment.

The rear wheel going on the bike is from a 1995 GXSR750 (straight three spokes)

The rear brake caliper as well as the matching hanger that came with it (that I want to use) is from a 1985 GS1150.

This brake setup allows the caliper to sit on the top side of the rotor with the torque arm bolting to the top side of the rear swingarm. (which is what I want & need)

The swingarm I have is your garden variety, lower braced JCM unit, pictured here:

 

I want to use this brake setup (I don't have it yet)

 

I need to make sure that I use a rear wheel shaft that will fit snugly through this caliper hanger, and my 95 GXSR750 wheel.

I've already done tons of research on these parts, including comparing their part numbers.

The problem is, I can't seem to find any data anywhere that gives dimensions.

The rear brake caliper hanger that I want to use is P/N: 69721-47011

The 1985 GS1150 rear wheel shaft is P/N: 61211-00A00, and it would absolutely fit the hanger listed above, but I have no idea if it would fit my swingarm, or wheel.

(you see how this is getting complicated)

 

The shaft diameter of the bolt that's currently residing in my swingarm is 20mm (0.787”) thick but obviously I don't have a part number for it because it came with the swingarm. My 1995 GSXR750 (three "straight" spoke) wheel fits on the shaft that's currently in the JCM swingarm if that helps.

I have to make sure that the inner diameter of the 85 GS1150 rear brake caliper hanger will fit the existing (20mm / 0.787") shaft that I have. (before I get it)

If not, then I need to source one that will not only fit the hanger, but inside the swingarm and wheel as well.

I've already tried looking these shafts up online for dimensions but you can't accurately gauge thickness from a picture online.

Also, I'm assuming that the thickness of the current shaft, and the shaft used for an 85 GS1150 would be different, but in reality they could be the same and I just don't know.

If any of you guys know of a site, or chart, or table that gives dimensions for these items, I'd be supper appreciative.

If any of you guys know "from experience" what will fit with what, I'd be supper appreciative.

 

                                                                                                          As always, thanks in advance.................... 

 

 

 

[slayer61]

I know for a fact that the GSX & GSXR both use 20mm axle, bearings & spacers, etc. Does that help?

[Dezza]

First, I would fit the swingarm to the frame to enable the centre of wheel to be in line with the centre of the headstock. You then will know what bits are going to fit and what modifications are going to be needed either side. What disc are you going to use? If you are using an EFE rear caliper and hanger, then you'll need a disc the same size as the one on an EFE, which is massive and will be unlikely to look right, unless great big rear discs float your boat (if you can find one to fit the wheel). You are going to need access to (someone who has) a lathe and a milling machine by the look of things. Also, why is this a seperate project thread?

[Neveragain55]

31 minutes ago, slayer61 said:

I know for a fact that the GSX & GSXR both use 20mm axle, bearings & spacers, etc. Does that help?

Tremendously, thank you.....

[Neveragain55]

14 minutes ago, Dezza said:

First, I would fit the swingarm to the frame to enable the centre of wheel to be in line with the centre of the headstock. You then will know what bits are going to fit and what modifications are going to be needed either side. What disc are you going to use? If you are using an EFE rear caliper and hanger, then you'll need a disc the same size as the one on an EFE, which is massive and will be unlikely to look right, unless great big rear discs float your boat (if you can find one to fit the wheel). You are going to need access to (someone who has) a lathe and a milling machine by the look of things. Also, why is this a seperate project thread?

Thanks.....

Most of all the things you mentioned have already been done, including lots of machining work to mate the swingarm to the frame, take a look:

All I need to know is...... if the hanger from that 85 GS1150 rear brake caliper will slide over the existing shaft (with no slop) that came with the swingarm.

As you can see, the wheel fits just fine, no worries there, and I'm just about positive that the 85 GS1150 brake caliper will fit perfectly over the rotor you see in the picture. I can easily have spacers made to shift the brake hanger closer or further away as needed (if it doesn't line up perfectly), and I can have a torque arm fabricated so that's not a problem either.

It just comes down to making sure I have a shaft that going to fit through the swingarm, wheel, and brake hanger.... 

I thought about continuing on with my other thread in here but typically when I do that I never get any hits.

I won't make any new threads in the future, I'll just stick with the main one that I created.

 

 

 

Edited January 26, 2021 by Neveragain55

[TonyGee]

the hole in the calliper hanger can easily be bored out to 20mm if it isn't already 20mm.  but looking at the pic of the calliper and hanger they look to long for the smaller disc you have ?  if you want the calliper on top then maybe a bandit hanger and a GS 500 calliper might be the way to go as they have the calliper on top. 

[Neveragain55]

7 hours ago, TonyGee said:

the hole in the calliper hanger can easily be bored out to 20mm if it isn't already 20mm.  but looking at the pic of the calliper and hanger they look to long for the smaller disc you have ?  if you want the calliper on top then maybe a bandit hanger and a GS 500 calliper might be the way to go as they have the calliper on top. 

Thanks TonyGee, excellent points, and I'll definitely look into it.......