Widen swingarm without welding

Trying to stuff a wide General 5 star hub in my Sachs swingarm. I need about another inch of width for everything fit nicely.

Anyone widen a swingarm with heat or a cold set? I'd like to avoid chopping it and welding if possible, however, I realize this may be hard to avoid if I want the swingarm to remain "symmetrical"(you know what I mean).

Re: Widen swingarm without welding

Dirty30 Dillon /

You can widen your swingarm with just brute force, but you might kink the tube, and you are going to loose tire height clearance.

Re: Widen swingarm without welding

> Dirty30 Dillon wrote:

> -------------------------------------------------------

> You can widen your swingarm with just brute force, but you might kink

> the tube, and you are going to loose tire height clearance.

I'm a bit confused, what do you mean kink the tube? There's nothing on the wheel currently but I can't just shove it in, that hasn't worked.

Totally open to a brute force option, just looking for one that keeps the spread of the swingarm a bit even. Ideally I still want the wheel centered.

Hopefully that made sense? Sorry if I'm being confusing.

Re: Widen swingarm without welding

Yeah you can pretty much just straight manhandle that shit, the hard part is getting everything to line back up.

I widened a maxi swingarm and rode on it that way for a while but it was a little off and you could tell.

Re: Widen swingarm without welding

Get a piece of allthread, or a long axle, put two nuts on it and some big washers, and stick it in the drop outs with the nuts and washers on the inside.

Then turn the nuts out so it spreads the swingarm.

Try to make sure it spreads evenly, or keeps your chain line where you want it , etc.

And make sure the bolt doesn't squirt out and hit you in the face under tension.

You'll have to go wider than you need because it'll try to squeeze back to it's original shape.

Make sure the tubes don't kink,crack, etc.

Re: Widen swingarm without welding

Dirty30 Dillon /

> Aaron Goldman wrote:

> -------------------------------------------------------

> > Dirty30 Dillon wrote:

>

> > -------------------------------------------------------

>

> > You can widen your swingarm with just brute force, but you might kink

>

> > the tube, and you are going to loose tire height clearance.

>

> I'm a bit confused, what do you mean kink the tube? There's nothing on

> the wheel currently but I can't just shove it in, that hasn't worked.

>

> Totally open to a brute force option, just looking for one that keeps

> the spread of the swingarm a bit even. Ideally I still want the wheel

> centered.

>

> Hopefully that made sense? Sorry if I'm being confusing.

By tube, I mean the steel tubing that comprises your swingarm. Not the tube inside the tire.

My suggestion would be to mount the swingarm in a vice, build a cheap reference jig to gauge total movement from stock (piece of thick wire off the vice that you can gauge movement in either direction), and use a pipe to cold bend it out.

Even the method baird mentioned has high fallibility, given that the swingarm won't naturally spread evenly. Whichever leg is slightly weaker will spread first.

Re: Widen swingarm without welding

Are you only widening the drop outs to account for the wider hub, or are you trying to fit a wider hub + wider tire?

Re: Widen swingarm without welding

> Dickie Thompson wrote:

> -------------------------------------------------------

> Are you only widening the drop outs to account for the wider hub, or are

> you trying to fit a wider hub + wider tire?

It has been a while since I last tinkered with this project but I'm 85% sure it's just the hub. I believe the tire has no issue fitting.

Re: Widen swingarm without welding

> Aaron Goldman wrote:

> -------------------------------------------------------

> > Dickie Thompson wrote:

>

> > -------------------------------------------------------

>

> > Are you only widening the drop outs to account for the wider hub, or

> are

>

> > you trying to fit a wider hub + wider tire?

>

> It has been a while since I last tinkered with this project but I'm 85%

> sure it's just the hub. I believe the tire has no issue fitting.

Did you already confirm that the chain alignment will work?

Re: Widen swingarm without welding

> Dickie Thompson wrote:

> -------------------------------------------------------

> > Aaron Goldman wrote:

>

> > -------------------------------------------------------

>

> > > Dickie Thompson wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > Are you only widening the drop outs to account for the wider hub, or

>

> > are

>

> >

>

> > > you trying to fit a wider hub + wider tire?

>

> >

>

> > It has been a while since I last tinkered with this project but I'm

> 85%

>

> > sure it's just the hub. I believe the tire has no issue fitting.

>

> Did you already confirm that the chain alignment will work?

Don't think so, good idea. I'll give that a whirl first and see if it can still be centered. Would be a bummer for sure, I wanted the bigger drum brakes.

Re: Widen swingarm without welding

General was sourced from a bunch of generic random Taiwan parts so there are a few variations on them but the one I had, had terrible brakes, very low quality and poorly finished. My Sachs on the other hand with the mags has killer brakes, especially with the coaster from the pedals.

If the only reason you're doing it is to get good brakes, I would just clean up the sachs brakes or find a better set of Sachs wheels.

Re: Widen swingarm without welding

> Graham Motzing wrote:

> -------------------------------------------------------

> General was sourced from a bunch of generic random Taiwan parts so there

> are a few variations on them but the one I had, had terrible brakes,

> very low quality and poorly finished. My Sachs on the other hand with

> the mags has killer brakes, especially with the coaster from the pedals.

>

> If the only reason you're doing it is to get good brakes, I would just

> clean up the sachs brakes or find a better set of Sachs wheels.

The plan was to run the 19” kx80 front end and the 16” general rear wheel with the coaster(who would delete that!?). Finding a regular Sachs rear coaster wheel can be a pain, oh well. Easier install I suppose, I can just finish the darn build.

Re: Widen swingarm without welding

Hammer and heat? It’s just mopeds and may not be straight….and can cause issues.

I widened a Tomos swing arm once by welding a spacer in the center…. but it keeps wearing out bearings. Definitely not square anymore. Natural Light and a flux mig are a bad combination. 10/10 don’t recommend.

Re: Widen swingarm without welding

You can isolate the bending wherever along the length of the swingarm you desire by heating red hot. Map gas torch will do it cheap.

Re: Widen swingarm without welding

> baird co wrote:

> -------------------------------------------------------

> Get a piece of allthread, or a long axle, put two nuts on it and some

> big washers, and stick it in the drop outs with the nuts and washers on

> the inside.

>

> Then turn the nuts out so it spreads the swingarm.

>

> Try to make sure it spreads evenly, or keeps your chain line where you

> want it , etc.

>

> And make sure the bolt doesn't squirt out and hit you in the face under

> tension.

>

> You'll have to go wider than you need because it'll try to squeeze back

> to it's original shape.

>

> Make sure the tubes don't kink,crack, etc.

I had to widen my garelli swingarm for the electric hub motor setup i built a few years ago, I did basically this, drift it apart with allthread. it worked but it wasnt a big stretch

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