torque link anchor point

[Dink]

this action of pulling the swingarm down or up is exactly why it should be frame mounted!!! Because if the brake forces are fed into the swingarm (i.e. by swingarm mounting) they must effect suspension action, due to the forces having to be absorbed by the suspension. If the brake torque is fed into the frame it allows the suspension to work independantly, the can be adjusted by the use of different length torque rods, if the torque rod is of equal length to the swingarm it will be neutral, if the torque rod is shorter than the swingarm it will create squat which is in some racing applications is desirable, however in a road application a torque rod slightly longer is most suitable, as it unloads the rear suspension and maximises the avaiable suspension travel ot cope with road irregularities, plus of cause it is also desirable if the suspension extends slightly to maintain rear tyre contact with the road. BTW the main reason that most manufacturers returned to swingarm mounting ids that it is cheaper to make and in most road applications the difference is not noticable particularly as the quality of stock suspension units has risen so much in recent years.
Dink
I apologise for not fully explaining the theory behind this in my first post

 

[Paul]

Dink
You're seem to be contradicting yourself.

You say - "Because if the brake forces are fed into the swing-arm (i.e. by swing-arm mounting) they must effect suspension action,"
Then you say - " If the brake torque is fed into the frame it allows the suspension to work independently,"
Then - "if the torque rod is of equal length to the swing-arm it will be neutral, if the torque rod is shorter than the swing-arm it will create squat"

If the suspension is to work independently, the position of the torque arm won't make any difference, conversely, if the torque arm mounting position affects the suspension (makes it squat, unload or neutral) the suspension is not acting independently!
I still think that if it is mounted on the swing arm the caliper cannot rotate about the axle, and the applied torque is contained within a fixed triangle of forces. The action of the rear brake cannot affect suspension then because the whole force triangle is closed.

Billy Ricks said - "Wouldn't venture to guess why Suzuki frame mounted the torque arm. But, if you mount it on the frame it is going to interfere with suspension movement. Once you tighten down on the axle the caliper can't rotate. If the torque arm is swing-arm mounted it doesn't have to go anywhere as the suspension moves. Frame mounted it has to be able to rotate slightly with the suspension."

Was the reason why Suzuki frame mounted it to do with the different types of mono-shock rear suspension, "rising rate" is one that springs to mind?
I cant under stand how it works because as you say- once the axle is tight how does the caliper move?

 

[Guest]

You are all talking about locking up the rear wheel. With applied braking the caliper can move. On my bike the caliper hanger has a bushing and spins around the axle, the link has a swival joint at the frame end. As the swingarm moves with braking so will the caliper..NO?

Suzuki has been racing along time and their engineers must have had this discussion too.

its time to ask the guys who are doing the racing and get their opinions because we can theorize all night....they are doing it and have the data on what realy works.

I taked to a racer today and he said the swing mount is the way to go if you have to but I am looking at mounting a new swing that has no link arm. A 2002 that has the bracket at the axle for the caliper.

Can anyone say...oooh yehhhh! Vey nice.

Katman

 

[Billy Ricks]

The '93 swingarm I'll be installing on my bike has no torque rod at all. The caliper hanger has a rail cast into it that slides in a notch on the swingarm itself. The only reason the caliper should rotate is for chain adjustments. The torque rod is there to keep the caliper from spinning under braking. Once you torque the axle to spec the caliper is going to have a tough time rotating as the suspension moves. With the rod frame mounted it is just about impossible to get the geometry to where the suspension wouldn't be effected. Swingarm mounting makes it perfectly neutral. The rod and swingarm are moving as a unit.

 

[Guest]

Billly,

What bike is your swing off?? is it on a gs???? will it fit my bike???gs1100.

thanks, Rob.

 

[Billy Ricks]

Rob,
It's off of a '93 GSXR750. It's the banana swingarm that they used that year so the exhaust can tucks in closer to the frame. It's not an easy mod on my bike. You have to 86 the stock peg arrangement. Then weld plates on the outer rear edge of the subframe for rearsets. I'm using Gixxer rearsets. Then the inside of the frame where the swingarm pivots has to be flycut to remove about 1/8" from each side to make room for the swingarm pivot. I'll be using my stock bushings shortened to fit the Gixxer unit so I can use the stock pivot shaft.

 

[Anonymous]

You need to keep the torque arm attaached to the swingarm, period.

Not true in this specific case.....

If, as I suspect, katman is using a underslung GSX-R type brake caliper, then he can put the torque link on the frame because these calipers are designed to rotate around the axle, even when it is fully torqued up. This type of caliper does not interfere with normal suspension movement - how can it if it's allowed some limited rotation?

If he were using a traditional solid mount GS-type caliper, he'd be in trouble. Most likely something would break if the arm were frame mounted (if it were at all possible to frame mount!) for the very reasons that have been mentioned - it would prohibit suspension movement.

Pat

 

[Billy Ricks]

Patrick,
I'm running a GSXR rear wheel, rotor, caliper, and everything else that goes with it. The point is, once the axle is torqued down the ability to rotate is basically non-existent. As the swingarm moves up and down the caliper would have to overcome that resistance to move at all. With the swingarm mounted torque rod the caliper doesn't have to move. With a frame mounted torque arm the suspension travel is going to cause the angles to change unless you have the torque rod anchored at exactly the same point as the center of the swingarm pivot, pretty much impossible to do. So then geometry takes over and the caliper has to move with suspension travel. It has to overcome the torque on the axle. That interferes with free movement of the suspension. If the best possible handling isn't an issue then frame mount it. Otherwise swingarm mounting is the best option.

 

[Guest]

Billy,

you are incorrect regarding the caliper. Even with the axle torqued down the caliper pivots..It is on a bushing. The bushing is static but the caliper is free to move. I can move it with my fingers. The frame mount creates a parallelegram whick seems to keep the caliper at the bottom of the disk with the movement of the swing.

katman

 

[Billy Ricks]

Kat,
I guess your set up is different than mine. I have my caliper under the swingarm. The caliper hanger doesn't allow for any movement once the axle is tightened down. The tab that the rod bolts to on the caliper has a bushing, but it is just there to allow for chain adjustments. If things were loose enough to allow for the hanger to rotate the axle would be moving back and forth in the swingarm.

 

[Guest]

Hey Billy,

check out this video of my rear wheel. the axle it torqued down and tight.

(video no longer available)


Cheers, and thanks for your input.

Katman.

 

[Billy Ricks]

Kat,
Just for grins I went out and pulled the torque rod off of my caliper. Mine has no bushing and goes nowhere. For solid caliper hangers the only way to go is swingarm mounted. Otherwise the suspension will be hampered by the caliper trying to rotate as the suspension tries to do its job. That rotation may be slight, but it would still hinder suspension movement. You would have to get the geometry perfect for it not to effect suspension travel. The perfect position would intersect the center of the pivot shaft. The rear wheel doesn't travel straight up and down. It has some arc as it moves. Since you have the bushing frame mounting the rod is fine.