Extra long rear axles? Where to find?

I have taken in an electric bike whose electric drive has irreparable
problems. The rest of the bike appears to be new, is very robust, and
has particularly long chainstays. I would like to configure it as a
load hauler and send it back to the community bike shop from where I
got it.

The problem is that its aluminum frame is blessed with about 162mm
rear spacing. Between its chunky construction and its probable lack
of post-weld heat treatment, I'd rather not respace it. Besides, if I
work with the spacing it's got, I could build it up as a dishless 7-
or 8-speed.

The only thing holding me up from this is my inability to find
sufficiently long rear axles. I know I can get good long leaf spring
center bolts in 3/8"-24 thread, but that would limit me to using cones
and locknuts from coaster brake hubs or ancient US-made BMX stuff, and
I'd rather not. Neither do I want to use QR axles from Santana
tandems, because corresponding super-long skewers are scarce and
expensive.

The longest axles I can find in 3/8"-26 or M10x1.0 are 187mm. I need
something at least 10mm longer than that, and preferably longer yet to
allow the use of a rear axle kickstand or axle-mounted trailer
hitch.

It should also be cheap, in keeping with the nature of the project.
McMaster-Carr has 300mm lengths of suitably strong rods with M10x1.0
threading, but they cost $30 each plus shipping.

Does anybody know of other options?

Chalo

On Sun, 29 Aug 2010 17:49:10 -0700 (PDT), Chalo
wrote:

Does anybody know of other options?

Well...

1. Buy unthreaded 3/8" steel rod. Thread the ends by hand to
whatever length is required. No need to thread the entire rod. Take
it to someone that does heat treating and have it hardened. I would
use 4130 (30Rc). Have it heat treated and annealed to about 41 to
45Rc.

2. If you don't care about heat treating, use cheap 1018 mild steel
and don't bother heat treating it. A heavy rider will probably bend
the axle, but if you give the owner some spares and a warning, it
might survive.
http://www.ehow.com/about_5199802_heat-treatment-1018-steel.html

3. You could also take two short axles, cut (grind) them to length,
chamfer the ends, and butt weld them together. If it's a hollow axle,
shove a rod down the center for reinforcement before welding (and
don't use skewers). You'll probably lose heat treating in the heat
affected zone, so try to minimize heating by using TIG, not gas
welding.

Personally, I think fixing the motor, whatever might be wrong with it,
might be easier.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:
On Sun, 29 Aug 2010 17:49:10 -0700 (PDT), Chalo
wrote:

Does anybody know of other options?

Well...

1. Buy unthreaded 3/8" steel rod. Thread the ends by hand to
whatever length is required. No need to thread the entire rod. Take
it to someone that does heat treating and have it hardened. I would
use 4130 (30Rc). Have it heat treated and annealed to about 41 to
45Rc.

2. If you don't care about heat treating, use cheap 1018 mild steel
and don't bother heat treating it. A heavy rider will probably bend
the axle, but if you give the owner some spares and a warning, it
might survive.
http://www.ehow.com/about_5199802_heat-treatment-1018-steel.html

3. You could also take two short axles, cut (grind) them to length,
chamfer the ends, and butt weld them together. If it's a hollow axle,
shove a rod down the center for reinforcement before welding (and
don't use skewers). You'll probably lose heat treating in the heat
affected zone, so try to minimize heating by using TIG, not gas
welding.

Personally, I think fixing the motor, whatever might be wrong with it,
might be easier.


You'd think so but the usual weak spot is the motor
controller which is a proprietary electronic assembly.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Sun, 29 Aug 2010 21:33:16 -0500, AMuzi wrote:

Jeff Liebermann wrote:
Personally, I think fixing the motor, whatever might be wrong with it,
might be easier.

You'd think so but the usual weak spot is the motor
controller which is a proprietary electronic assembly.

I'm an electronics type, so such things are easier for me than the
metalwork. Proprietary doesn't bug me, but having the entire
controller potted in epoxy will prevent any component level repair.

There are replacements available. For example, for e-Bike:
http://www.scooterparts4less.com/all_electric_scooter_parts.htm
http://www.electricscooterparts.com/speedcontrollers.html
http://www.ebikecontroller.com
I helped rebuild an e-Bike conversion where the owner used a 24V
aircraft battery charger directly to the battery. It worked ok as
long as the battery was connected. However, when battery went open
circuit one day, the over voltage blew up the controller. $20 used on
eBay for a replacement.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

AMuzi wrote:

Jeff Liebermann wrote:

Personally, I think fixing the [e-bike] motor, whatever might be wrong with it,
might be easier.

You'd think so but the usual weak spot is the motor
controller which is a proprietary electronic assembly.

In this case, it was two things: the expensive lithium battery was
DOA, and the hollow rear axle end-- which is machined into the motor
armature shaft and is the conduit through which the motor wires pass--
was made of such soft crappy steel that it had stretched from the
tension of the axle nut. (It evidently did so without even having
built up enough clamping force to restrain the axle from slipping.)

I may be able to press that motor into use as something besides a
bicycle wheel, but its road-going days are over.

As far as I know, the controller is fine. But I'll not try to restore
this particular e-bike to its previous motorized configuration. It
was a heap o'crap e-bike anyway, but it won't be too bad as a heavy
hauler.

Chalo

On 30 Aug, 01:49, Chalo wrote:
I have taken in an electric bike whose electric drive has irreparable
problems. *The rest of the bike appears to be new, is very robust, and
has particularly long chainstays. *I would like to configure it as a
load hauler and send it back to the community bike shop from where I
got it.

The problem is that its aluminum frame is blessed with about 162mm
rear spacing. *Between its chunky construction and its probable lack
of post-weld heat treatment, I'd rather not respace it. *Besides, if I
work with the spacing it's got, I could build it up as a dishless 7-
or 8-speed.

The only thing holding me up from this is my inability to find
sufficiently long rear axles. *I know I can get good long leaf spring
center bolts in 3/8"-24 thread, but that would limit me to using cones
and locknuts from coaster brake hubs or ancient US-made BMX stuff, and
I'd rather not. *Neither do I want to use QR axles from Santana
tandems, because corresponding super-long skewers are scarce and
expensive.

The longest axles I can find in 3/8"-26 or M10x1.0 are 187mm. *I need
something at least 10mm longer than that, and preferably longer yet to
allow the use of a rear axle kickstand or axle-mounted trailer
hitch.

It should also be cheap, in keeping with the nature of the project.
McMaster-Carr has 300mm lengths of suitably strong rods with M10x1.0
threading, but they cost $30 each plus shipping.

Does anybody know of other options?

Chalo

That's a ridiculous price for threaded rod, find someone else.

On 30 Aug, 04:14, Jeff Liebermann wrote:
On Sun, 29 Aug 2010 21:33:16 -0500, AMuzi wrote:
Jeff Liebermann wrote:
Personally, I think fixing the motor, whatever might be wrong with it,
might be easier.
You'd think so but the usual weak spot is the motor
controller which is a proprietary electronic assembly.

I'm an electronics type, so such things are easier for me than the
metalwork. *Proprietary doesn't bug me, but having the entire
controller potted in epoxy will prevent any component level repair.

There are replacements available. *For example, for e-Bike:
http://www.scooterparts4less.com/all_electric_scooter_parts.htm
http://www.electricscooterparts.com/speedcontrollers.html
http://www.ebikecontroller.com
I helped rebuild an e-Bike conversion where the owner used a 24V
aircraft battery charger directly to the battery. *It worked ok as
long as the battery was connected. *However, when battery went open
circuit one day, the over voltage blew up the controller. *$20 used on
eBay for a replacement.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558

Yeah, no such thing as irrepearable, a 24V motor, just switch in 4A
with an SCR, no worries.

On 30 Aug, 06:25, Chalo wrote:
AMuzi wrote:

Jeff Liebermann wrote:

Personally, I think fixing the [e-bike] motor, whatever might be wrong with it,
might be easier.

You'd think so but the usual weak spot is the motor
controller which is a proprietary electronic assembly.

In this case, it was two things: *the expensive lithium battery was
DOA, and the hollow rear axle end-- which is machined into the motor
armature shaft and is the conduit through which the motor wires pass--
was made of such soft crappy steel that it had stretched from the
tension of the axle nut. *(It evidently did so without even having
built up enough clamping force to restrain the axle from slipping.)

I may be able to press that motor into use as something besides a
bicycle wheel, but its road-going days are over.

As far as I know, the controller is fine. *But I'll not try to restore
this particular e-bike to its previous motorized configuration. *It
was a heap o'crap e-bike anyway, but it won't be too bad as a heavy
hauler.

Chalo

Shove a 30Ah car battery on it and see, with a bit of luck you will
short circuit the battery and have to use the CO2 to chill it all down.

thirty-six wrote:

Chalo wrote:

McMaster-Carr has 300mm lengths of suitably strong rods with M10x1.0
threading, but they cost $30 each plus shipping.

That's a ridiculous price for threaded rod, find someone else.

That's right, which is why I didn't simply buy it. But metric extra
fine thread alloy steel rod doesn't exactly grow on trees in the U. S.
of A.

Chalo

thirty-six wrote:

Chalo wrote:

AMuzi wrote:

You'd think so but the usual weak spot is the motor
controller which is a proprietary electronic assembly.

In this case, it was two things: *the expensive lithium battery was
DOA,

Shove a 30Ah car battery on it and see, with a bit of luck you will
short circuit the battery and have to use the CO2 to chill it all down.

http://www.youtube.com/watch?v=k5f0VCoFuFM

Chalo