Gixxer rear wheel/caliper

[scotiafj]

Howdo folks I keep coming back to this problem on my rear wheel swap ,the caliper torque arm bolt from the right side foot peg (where the torque armis mounted to as per mod ) keeps snapping every few yrs ,its the rose jointed torque arm and the caliper with the bushes in it , even tho the spindle nut is torqued up to spec the caliper mount can still move back and forth slightly ,Im thinking this is the cause of the bolt @ the front snapping ,? also the tab on the caliper where the torque arm bolts to has a bushing there too, what torque does that bolt get so that the bush can move freely ? cheers

[Pat Conlon]

Weld a tab on your swinger and be done with it.
I've never liked the idea of bolting the brake stay arm to a frame point that has a different arc than the axle on the swing arm....but that's just me.

[racerrad8]

I had not ever heard of this being an issue until just last month. Ron had his break on his way home from the 2019 WCR: http://www.fjowners.com/index.php?topic=18337.msg189047#msg189047

I would venture to say the reason the bolts are breaking is the fact they are in a "single shear" position. The torque of the brake caliper is pushing the bolt forward when braking and then back when the brakes are released.

If there was a way to put the bolt in double shear, then I doubt you would have any problem.

The welding of two tabs onto the swing arm on both side of the rose joint makes it a double shear design.

Rick, you should probably replace your bolt before it breaks...

Randy - RPM

[scotiafj]

I had not ever heard of this being an issue until just last month. Ron had his break on his way home from the 2019 WCR: http://www.fjowners.com/index.php?topic=18337.msg189047#msg189047

I would venture to say the reason the bolts are breaking is the fact they are in a "single shear" position. The torque of the brake caliper is pushing the bolt forward when braking and then back when the brakes are released.

If there was a way to put the bolt in double shear, then I doubt you would have any problem.

The welding of two tabs onto the swing arm on both side of the rose joint makes it a double shear design.

Rick, you should probably replace your bolt before it breaks...

Randy - RPM

Yep thats what was happening to mine ..luckily I was hearing a click when I was braking when I had a look the bolt had snapped off inside the frame but could be pulled out so I left it in with torque arm still connected then zip tied the torque arm further down to the footrest where the brake lever pivots so the tension on from the zip tie would keep the arm/ bolt in the frame till I got home ..it happened before a couple of years ago and I did the zip tie mod to get home ...time to think of some other where to fix the torque arm to or go the yzf600 wheel/caliper route

[roortcloud]

This is the solution I came up with to secure the torque arm of the GSXR rear brake caliper. It utilized both of mounting bolts of the right side foot peg instead of just hanging on one.
I have a detailed drawing of this part if any other member is interested.
Ron

[scotiafj]

This is the solution I came up with to secure the torque arm of the GSXR rear brake caliper. It utilized both of mounting bolts of the right side foot peg instead of just hanging on one.
I have a detailed drawing of this part if any other member is interested.
Ron

Yeah I'd like a copy of the drawing,

[aviationfred]

I am also with Randy, until just the last couple of weeks, I have never heard of a bolt breaking for the Gixxer anti torque arm.

I did the mod to my 89 very shortly after I purchased it. 5 years and roughly 40,000 miles without a problem with the anti torque arm bolt. I did mount mine a bit different than what is in the write up and the accompanying photo.

I left the foot peg bolt alone. I noticed when I bolted the torque arm up to the frame that the alignment was not straight with the caliper. I found a small aluminum spacer for the bolt, about 1/4" in length and the OD of the spacer was slightly larger than the bearing hole. That made the alignment almost perfect. I did NOT use a washer under the cap screw head. The cap screw and spacer allows for any side load placed on the bearing. In the photo, (page 2, second photo in the PDF file) if you were to snug the nut very tight, it would appear that the amount of torque arm rotation from the swing arm going up and down would also be severely restricted.

I would surmise that with 2 possible forces working against the small 6mm bolt that a failure could happen.



Fred

[scotiafj]

I am also with Randy, until just the last couple of weeks, I have never heard of a bolt breaking for the Gixxer anti torque arm.

I did the mod to my 89 very shortly after I purchased it. 5 years and roughly 40,000 miles without a problem with the anti torque arm bolt. I did mount mine a bit different than what is in the write up and the accompanying photo.

I left the foot peg bolt alone. I noticed when I bolted the torque arm up to the frame that the alignment was not straight with the caliper. I found a small aluminum spacer for the bolt, about 1/4" in length and the OD of the spacer was slightly larger than the bearing hole. That made the alignment almost perfect. I did NOT use a washer under the cap screw head. The cap screw and spacer allows for any side load placed on the bearing. In the photo, (page 2, second photo in the PDF file) if you were to snug the nut very tight, it would appear that the amount of torque arm rotation from the swing arm going up and down would also be severely restricted.

I would surmise that with 2 possible forces working against the small 6mm bolt that a failure could happen.

Yeah I think also because the caliper mount where the spindle goes thru can pivot back and forth slightly under braking which can put back and forth movement thru the bolt ..hmm need to think of something else to secure the arm , or change the back wheel/brake setup completely .

[ZOA NOM]

Never had a problem with any of the three bikes, but I do like Ron's solution. I'll have to check it out. I've used the footpeg bolt method as well as welding a tab to the swinger.

Also, I think this is backwards... The underslung caliper should pull the torque arm to the rear when braking. Unless you're in reverse, of course. 

I would venture to say the reason the bolts are breaking is the fact they are in a "single shear" position. The torque of the brake caliper is pushing the bolt forward when braking and then back when the brakes are released.

[racerrad8]

Also, I think this is backwards... The underslung caliper should pull the torque arm to the rear when braking. Unless you're in reverse, of course. 

I would venture to say the reason the bolts are breaking is the fact they are in a "single shear" position. The torque of the brake caliper is pushing the bolt forward when braking and then back when the brakes are released.

I was referring to the top mounted caliper position regarding the load on the bolt.

Potato/PoTAto...either way  the forces manipulate the bolt, the mounting is of single shear design.

Randy - RPM

[ZOA NOM]

Also, I think this is backwards... The underslung caliper should pull the torque arm to the rear when braking. Unless you're in reverse, of course. 

I would venture to say the reason the bolts are breaking is the fact they are in a "single shear" position. The torque of the brake caliper is pushing the bolt forward when braking and then back when the brakes are released.

I was referring to the top mounted caliper position regarding the load on the bolt.

Potato/PoTAto...either way  the forces manipulate the bolt, the mounting is of single shear design.

Randy - RPM

Never seen the torque arm mounted to the factory caliper... Wouldn't you just keep the factory mount and leave the footpegs alone?

[racerrad8]

I was referring to the top mounted caliper position regarding the load on the bolt.

Potato/PoTAto...either way  the forces manipulate the bolt, the mounting is of single shear design.

Randy - RPM

Never seen the torque arm mounted to the factory caliper... Wouldn't you just keep the factory mount and leave the footpegs alone?

Your right, I guess I should have never added any sort of comment to this issue.

Thank you Ron for posting up a solution to a problem. I hope scotiafj is able to resolve his issue with the bracket.

Rick, sorry I mentioned you might want to check and/or replace your. Since this seems to be a pretty significant safety consideration, I felt it prudent to mention it.

I'm out.

Randy - RPM

[ZOA NOM]

Wow, touch a nerve?

[Pat Conlon]

With the brake stay (aka: torque arm) bolted to the frame, as the rear axle moves up and down the brake caliper moves back and forth (front to rear) on the rotor.

A tab welded on the the swinger for anchoring the stay stops this movement.

[FJmonkey]

A drill and bolt on option was my choice for the under slung brake stay. I used Riv-Nuts and a simple sheet metal bit. I noticed after the fact that Yamaha already had them on my '86 swing arm in other places.