Single sided swinarm?

Hegel · Jan 4, 2010

Hi guys,

Happy new year to you all!

Do any of you know of a company/s that makes custom single sided swing arms? I seem to remember there were a few, tho I can't remember the names?

I was also looking as to whether a Triumph speed triple(Or something) S/A could be adapted...It might well be that it'd take too much time/money to do this, when the bespoke swing arm might be a better option. I've been toying with the idea of putting one on a Commando. If not the current one, then most likely the next.

Thoughts?

Steve

Tintin · Jan 4, 2010

Hegel said:
Do any of you know of a company/s that makes custom single sided swing arms?

I know of one here in Germany who does every kind of s/a you'd be able to dream up:

http://krueger-junginger.de/

I've been toying with the idea of putting one on a Commando. If not the current one, then most likely the next.

Thoughts?

I wouldn't bother to retrofit a technically inferior solution.... :wink:

Single sided arms are usually more heavy as the have to cope with an additional moment a double sided doesn't have - that's why Ducati went back to the normal layout when they realised they don't do endurance with the 916 family, the only benefit is for very quick wheel changes. Furthermore it would only make sense when you convert to a single sus unit as well and then it's more of a bespoke frame with s/arm, I could see a single sided arm in Jim Schmitd's monoshock frame: http://users.gotsky.com/jimschmidt/monoframe.html

Tim

Hegel · Jan 4, 2010

Hi Tim,

Thanks for the reply and the link

The single sided item is...I suppose a more aesthetic consideration, more than a practical one. But of course ditching the twin shock, moving to a mono is further up the importance ladder.

I've just been having a mooch on the link you sent, they've got some nice hardware to look at.

I'll send them a mail, see if they can help me out if I can't find one closer to home. Oh...I'm in the Uk btw.

Thanks again!

Steve

grandpaul · Jan 4, 2010

I kinda like my custom monoshock design. Very soon, I'll be getting it out on the track for REAL testing.

Yes, it's heavier, but it's also stronger.

Plus, it's cool.

Hegel · Jan 4, 2010

Grandpaul,

I was following your thread with the mono-shock with great interest. I've been thinking of building a special with the idea of creating a pseudo-contemporary S type. For some reason it's an idea that I just can't seem to put down. Once I've done the second metal bashing course (Feb) I'm going to break out the CAD software, make some drawings, see what I can create.

Was it you that posted a drawing of the mods (Shock bracket) to the frame? Are there any specific geometry considerations I need to take into account?

Be interested to hear of your exploits with your mono-shock

S

grandpaul · Jan 4, 2010

Well, short of custom fabrication of a set of yokes for the modern inverted forks, I'm pretty much stuck with the rake/trail of whatever brand/model fork I'm installing.

I'm attempting to make whatever adjustment possible by raising or lowering the rear end of the bike, and using different sized rims & tire profiles as required to bring the package into a semblance of stable geometry.

I'll let you know how I get on...

Tintin · Jan 4, 2010

grandpaul said:
I kinda like my custom monoshock design. Very soon, I'll be getting it out on the track for REAL testing.

I'd be surprised if you don't like your design.... :wink:

And I can easily imagine a single sided s/arm in your design too, that's true.

Yes, it's heavier, but it's also stronger.

Plus, it's cool.

The thing is that a SSA would be weaker and more heavy than a DSA.

Tim

grandpaul · Jan 4, 2010

I agree that a single-sided swingarm has even more drawbacks than a monoshock swingarm.

I'm not even thinking of designing and building one, though. You'd need one of those monster axles and other stuff that's just byond the pale.

ML · Jan 4, 2010

Solution is not in a single sided swing arm, its that puny pivot pin and housing in the back of the gear box cradle. If you had to (for what ever bizarre reason) design and fit a single arm, the re-engineering of the whole cradle and mounting would be the biggest challenge. Remember, this is a fundamental component of the isolastic performance. Twin arm is always going to be stronger and the focus should be on beefing up the pivot.

Mick

RennieK · Jan 4, 2010

ML said:
Solution is not in a single sided swing arm, its that puny pivot pin and housing in the back of the gear box cradle. If you had to (for what ever bizarre reason) design and fit a single arm, the re-engineering of the whole cradle and mounting would be the biggest challenge. Remember, this is a fundamental component of the isolastic performance. Twin arm is always going to be stronger and the focus should be on beefing up the pivot.

Mick

You said it Mick. I've thought of this scenario too and that was an obvious issue. There would inevitably be some twisting forces to deal with that you don't get with stereo. A more robust cradle would be a necessity and since that bolts to the back of the engine cases these forces would transfer to the mount points there.

Hegel · Jan 5, 2010

grandpaul,

I seem to remember reading an article about a guy who'd designed a set of adjustable yokes, you could play around with the rake/trail, not the (duolever,btw). IIRC it was in the U.K's MCN weekly paper. If I find a link I'll post it up.

Rennie,

I was thinking of a tougher engine cradle also. I forget...What's the standard one made out of anyway? Mild steel?

RennieK · Jan 5, 2010

Yes the engine plates are fairly mild. You can get dural cradles from Hemmings or Norvil, can't remember who has them.

grandpaul · Jan 5, 2010

Hegel, those adjustable yokes are all the rage in (dirt) flat track racing. $pendy bits!

Hegel · Jan 7, 2010

grandpaul,

Yeah I can imagine :roll:

I suppose another option could be to get some billet yokes made, play with the rake angle a bit. I'm not sure how much of a difference it'd make to the ease of steering? Since the bike I'm planning will be fairly tall, I guess the thing to be would to fit some wider bars, increase the leverage.

S

Single sided swinarm?

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