Srad swingarm in slingy

[Swirl]

Had a look round the Web I've got a 750m slingy frame there, a complete srad front end that I presume will go in no, with maybe a bearing swap, now we come to the swingarm, the srad spindle is larger than the slingshot, I have read using the internal sleeve from the slingshot swingarm bearing in the complete srad bearing will sleeve it down ok, do you use the srad linkage shock etc does it all bolt up

[MeanBean49]

Ive put K-series arms in this way, s-rad are pretty similar. I use slingshot shock and linkage and make adjustable dog bones.

The biggest issur is the 10mm different sprocket iffset between slingshot and s-rad rear wheels. I ended up machining down sprocket carrier and offsetting front sprocket a bit to get it all in line.

Anyone that tells you you can get the chain run straight and the wheel central without doing anything is wrong.

[no class]

Slingshot swingers have top mounted dogbones and srad or k series have lower mounted bones.....changing the angle on the dogbones without changing the pivot or shock will upset the geometry of how the suspenion functions smoothly..... I have found from past builds regarding lower mounted linkages that the ride is stiffer.....

[Swirl]

Well I've got a srad 750 arm with all the wheel brake hanger brakes shock knuckle the lot, but I have also a k1 arm on its own would it be easier to transplant all the srad stuff into the k1 arm

[MeanBean49]

Angle of the dog bones has no effect. Angle of linkage and swingarm does, as does the distance fron swingarm pivot to where dog bones attatch to swingarm, S-rad, k-series and slingshots are virtually same. Making shorter dog bones that go underneath not on top wont have any effect if the swingarm angle and linkage  stay the same/similar.

Certainly had no issues whatsoever when i do this on my slingshot race bikes

[no class]

I don't think so ....but you can have it your way if you want .

 

[Swirl]

Well I'm gonna find out, I've got both srad and k1 arms so we will see 

[no class]

this is a pic I pulled from the net (slingy with busa arm) ......the "leverage" action of the lower mounted bones will have a harder time as suspension travel increases .........the black lines mimic where the "top" mounted bones would be .....leverage will be easier as suspension travel increases . both ways will work....unfortunately one will be less efficient ......so using the stock slingy shock and pivot link that was designed to be top mounted on the swingarm by Suzuki engineers ......and  re-positioning the bones underneath the arm .....changes the geometry of how it was designed to work .

[MeanBean49]

23 hours ago, no class said:

this is a pic I pulled from the net (slingy with busa arm) ......the "leverage" action of the lower mounted bones will have a harder time as suspension travel increases .........the black lines mimic where the "top" mounted bones would be .....leverage will be easier as suspension travel increases . both ways will work....unfortunately one will be less efficient ......so using the stock slingy shock and pivot link that was designed to be top mounted on the swingarm by Suzuki engineers ......and  re-positioning the bones underneath the arm .....changes the geometry of how it was designed to work .

No it really doesnt. This picture doesnt represent what im saying at all. Changing the length of those dog bones alters the position of the swingarm, thats what changes the geometry.

Dog bones that are longer or shorter have no real effect if the position of the mount on the swingarm is the same distance from the swingarm pivot. The forces applied are exactly the same.

Like pulling a weight off the floor with a 0.5 m rope or a 1m rope, the force to lift the weight is the same

[MeanBean49]

No problems here

[Captain Chaos]

24 minutes ago, MeanBean49 said:

No it really doesnt. This picture doesnt represent what im saying at all. Changing the length of those dog bones alters the position of the swingarm, thats what changes the geometry.

Dog bones that are longer or shorter have no real effect if the position of the mount on the swingarm is the same distance from the swingarm pivot. The forces applied are exactly the same.

Like pulling a weight off the floor with a 0.5 m rope or a 1m rope, the force to lift the weight is the same

the angle between the dog bones and the pivot link has a big influence on how it works. Dogbones mounted on top of swingarm = larger angle (closer to 90 degrees) = lower force needed to move the pivot a certain amount. Dogbones mounted on bottom of swingarm (which happen to be shorter) means larger force needed.

So in short the dogbone length has no influence, but it's the angle at which they pull on the pivot link that matters.

[Swirl]

looks like ill be giving you a shout meanbean for some measurements.

[no class]

1 hour ago, Captain Chaos said:

the angle between the dog bones and the pivot link has a big influence on how it works. Dogbones mounted on top of swingarm = larger angle (closer to 90 degrees) = lower force needed to move the pivot a certain amount. Dogbones mounted on bottom of swingarm (which happen to be shorter) means larger force needed.

So in short the dogbone length has no influence, but it's the angle at which they pull on the pivot link that matters.

..... could not have said it better myself !  ....Thought that triangle I put in that pic was enough to explain .

[Captain Chaos]

here's an example. On the EFE I bought many years ago, the dogbones angle is too small in relation to the pivot. Suspension travel is only a few cm and very stiff. 

[davecara]

I've got a 750 srad arm in my slingy, using the srad knuckle and adjustable dog bones. 

Havent done many miles on it but it all works ok! 

[Swirl]

Cool, might pop round and have a look. I'm gonna find out, I've got both srad and k1 arms so we will see 

[davecara]

3 hours ago, Swirl said:

Cool, might pop round and have a look. I'm gonna find out, I've got both srad and k1 arms so we will see 

Yeah no probs, you've got my number and I'm only up the road