Aluminum Swingarm Swap: Favorite Mod Ive Done

[GgarryP]

As an engineer I doubt the frame is stiff enough to handle the eccentric loads from a single sided swing arm.

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[Junkie]

Why would a properly designed SSSA apply eccentric loads? If the wheel is in the same place as before, and the weight is the same, the loads should be the same. I know weight might not really be the same, but I doubt that's a major problem.

 

[GgarryP]

The overall loads would remain the same. How those loads get transferred through the frame and connections would be different.
For a typical swingarm the load on both bearings would be equal (although one bearing would see additional load from the drive chain). For a single-sided swingarm (side-arm?) the bearing on that side would see most of the load and the frame would have to be designed for it.
JMHO

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[Jt105]

On a single side swingarm, the axle is basically a lever that is trying to twist the swingarm. That ‘twist’ is transferred to the frame at the mounting points.
A double side swingarm, like what we have on the NC, does not twist because both sides of the axle are supported.

JT

 

[Junkie]

Are you assuming there's significant deformation in the SSSA or something? The swingarm is close enough to statically determinate that, absent something significant that I'm missing, the loads taken by the frame have nothing to do with the rigidity of the arm. I'd model it with pins at the front corners (at bearing locations), a force at the linkage mount, an upward and forward force at the tire contact patch (turned into whatever force/moment there is at the axle), and a forward (and slightly down) force where the chain pulls on the sprocket.

I assume that a static model is adequate for this, I suppose I could be wrong. The front of the SSSA is a large enough item that I'd expect the forces at the frame to be the same between the two swingarms.

 

[Junkie]

On a single side swingarm, the axle is basically a lever that is trying to twist the swingarm. That ‘twist’ is transferred to the frame at the mounting points.
A double side swingarm, like what we have on the NC, does not twist because both sides of the axle are supported.

JT

there's twist in the swingarm itself but the swingarm is essentially statically determinate so it's reactions on the frame are independent of it's rigidity.

 

[670cc]

I’m going to agree with Junkie, without much attempting to explain it, that the swing arm bearing loads would be the same whether they support a single or two sided swing arm.

Imagine you had a single sided swing arm. You add a bar to one side and run an axle through the wheel. How does that change the load on the swing arm bearings? The forces between the motorcycle frame and the wheel are still the same, and the swingarm still applies those forces to the frame through the same bearings.

That being said, I can’t think of any reason why you’d want a single sided arm on the NC, except if it could make tire changes easier.

 

[Jt105]

That is true... but I cannot tell you how many single sided scooters I’ve seen with rear wheels twisted. Overload the bike and everything twists.
I agree If the frame and swingarm are designed properly then the forces should be neutral.

JT

 

[Afan]

Hey All,

Awhile back a user posted on the UK forum showing the Aluminum swing arm from a Honda NC750 Integra was a bolt on fit for the NC750x

So I asked around and figured it would work for my NC700x. I picked one up on ebay from Italy and just finally got it swapped. I'm not sure but I think this might be the only NC in the US with this swap.

It looks so much better than the original painted steel one and weighs about 7lbs less.

The only downside is that the chainguard or any combo rear fender chainguard has to be for this swing arm as the mounting points are different.

Sorry for the shitty picks I wanted to get some shots before the rain started. Plus I need to do a good clean from this winters riding.

I'm super happy with this upgrade

Now for a new exhaust, seat, and headlight assembly. Then I think I'll be done with it.

If you don't mind me asking (maybe dummy question), why you did it? What's the gain? Just because it looks better? 7 lbs lighter? What else?

 

[frozenpoet]

If you don't mind me asking (maybe dummy question), why you did it? What's the gain? Just because it looks better? 7 lbs lighter? What else?

I can't answer for him, but I'm interested in this and the main reason would be, because I can.

Weight savings and the better chain adjusters are nice too.

 

[fleetingyouth]

The main reason I did it was because I hated the way it looked and when I saw how Wingriders looked with the better one I loved it.

I didnt spend a ton on it and Ive done a bunch of cosmetic mods like the tail delete that really makes the bike look better to me.

There are benifits, its much lighter I think more than my original estimate of 7lbs. Its a stronger better performance part overall.

I'm also not the type of person that will ever upgrade or buy another bike until this one is broken, stolen or not worth investing in. So making cosmetic changes that make the bike more of what I want are worth it to me.

 

[nttra]

The main reason I did it was because I hated the way it looked and when I saw how Wingriders looked with the better one I loved it.
...

I'm also not the type of person that will ever upgrade or buy another bike until this one is broken, stolen or not worth investing in. So making cosmetic changes that make the bike more of what I want are worth it to me.

I like and respect this way of thinking. I'm the same way.
My NC700x is by no means a sport bike, and that's OK with me since the hormonal need for speed has vanished overt the years. Although there are 3 things I love about it: fuel economy, practicality, and the looks. I've read a lot of post about swingarm conversions (mostly on sport bikes and cafe racers), and I always loved the look of the Hypermotards and VFR, and now I am curious to have this project going.

Just a quick question about your swap: do you happen to measure the dimensions of the OEM swingarm. Specifically the Pivot length, width and diameter? That would be great to have that info to cross reference with the specs mentioned in THIS OTHER THREAD.

Thanks for sharing and congratulations on the mod. It looks way better than stock!

 

[Junkie]

The two cosmetic things I'd like to do on mine are the swingarm and tail tidy - not a big fan of the huge fender and the French integrated setup is pretty slick.

Beyond that, all I've considered is adding lighting.