slipping rear axle on cargobike with schlumpf drive

Hello

A friend of mine has a Nihola cargobike with a sram seven-speed hub, and a
schlumpf mountain drive. When he pedals in the bottom granny gear, the
rear axle slips a little. Apparently the nut is non-standard, so he can't
change that.

How does one solve this problem? locktite or something?

thanks
Erik Sandblom

--
Oil is for sissies

On Jan 24, 2:15 pm, "Erik Sandblom" wrote:
Hello

A friend of mine has a Nihola cargobike with a sram seven-speed hub, and a
schlumpf mountain drive. When he pedals in the bottom granny gear, the
rear axle slips a little. Apparently the nut is non-standard, so he can't
change that.

How does one solve this problem? locktite or something?

Grease (moly grease would be outstanding for this) on the axle
threads. Less friction at the threads means more clamping force for a
given amount of fastener torque.

I'd be rather surprised if the nuts weren't some standard thread;
there are at least four common threads for rear axles. A track nut
with a captive serrated washer (greased of course) might give better
bite. And if all else fails and the axle bosses are long enough, he
can just add a sharp toothed washer on each side under the existing
nut.

Chalo
Chalo

On Jan 24, 3:14 pm, Chalo wrote:
On Jan 24, 2:15 pm, "Erik Sandblom" wrote:

Hello

A friend of mine has a Nihola cargobike with a sram seven-speed hub, and a
schlumpf mountain drive. When he pedals in the bottom granny gear, the
rear axle slips a little. Apparently the nut is non-standard, so he can't
change that.

How does one solve this problem? locktite or something?

Grease (moly grease would be outstanding for this) on the axle
threads. Less friction at the threads means more clamping force for a
given amount of fastener torque.

Yeah, that's a given, and probably the solution. Depending on the
dropouts, the OP might be able to use some tug nugs. I've got some on
my Redline and love how they keep the chain tension in "memory" for
when I reinstall the rear wheel.

http://tinyurl.com/372t9y

They're pretty easy to find, just call a BMX bike shop and see what
they have. But do be aware that they need rear opening dropouts to
work.

"Erik Sandblom" wrote:
A friend of mine has a Nihola cargobike with a sram seven-speed hub, and a
schlumpf mountain drive. When he pedals in the bottom granny gear, the
rear axle slips a little. Apparently the nut is non-standard, so he can't
change that.
How does one solve this problem? locktite or something?

Chalo wrote:
Grease (moly grease would be outstanding for this) on the axle
threads. Less friction at the threads means more clamping force for a
given amount of fastener torque.

I'd be rather surprised if the nuts weren't some standard thread;
there are at least four common threads for rear axles. A track nut
with a captive serrated washer (greased of course) might give better
bite. And if all else fails and the axle bosses are long enough, he
can just add a sharp toothed washer on each side under the existing
nut.

I agree lubrication and proper torque are probably the right solution.

SRAM Super Sevens are sensitive to right side axle spacing, there's not
much room for a heavy washer or an extra one. The SRAM supplied tab
washer is pretty well formed and 'bitey'.
Thread is somewhat larger than a 10mm QR or track axle and it's 26tpi
not 1.0mm pitch so use the original SRAM axle nuts.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Jan 24, 3:55*pm, A Muzi wrote:

I agree lubrication and proper torque are probably the right solution.

SRAM Super Sevens are sensitive to right side axle spacing, there's not
much room for a heavy washer or an extra one. *The SRAM supplied tab
washer is pretty well formed and 'bitey'.
Thread is somewhat larger than a 10mm QR or track axle and it's 26tpi
not 1.0mm pitch so use the original SRAM axle nuts.

IIRC, the thread is 10.5mm by 26tpi. Don't ask me why- I just work
here and I *still* haven't gotten my paycheck.

Jeff

----------------------------------------------------------------------------------------------------------------------------------
1919: Green Bay football team loses to the Beloit "Fairies". Such are
legends.
----------------------------------------------------------------------------------------------------------------------------------

Erik Sandblom wrote:
Hello

A friend of mine has a Nihola cargobike with a sram seven-speed hub, and
a schlumpf mountain drive. When he pedals in the bottom granny gear, the
rear axle slips a little. Apparently the nut is non-standard, so he
can't change that.

How does one solve this problem? locktite or something?

thanks
Erik Sandblom


With a hubgear the axle should be restrained from rotating(due to the
torque on the axle in low gears) with a tabbed washer. Check that it is
in place and not a sloppy fit on the axle or in the dropout. Srams are
fitted with a single washer as standard, i'd try to instal 2 or 4 as
you're doing terrible things to it with the Schlumpf

thread is FG 10.5
--
/Marten

info(apestaartje)m-gineering(punt)nl

A Muzi wrote:

Thread is somewhat larger than a 10mm QR or track axle and it's 26tpi
not 1.0mm pitch so use the original SRAM axle nuts.

Right; I knew that about Sachs hubs and their descendants, but for
some reason I thought I was discussing a threaded-axle Rohloff hub.
Those are M10x1.0 to my knowledge.

I find it easy to damage the thread in Sachs axle nuts because of the
interruption imposed by the axle flats. Good lube and sensitive
tightening are all I can recommend. For whatever reason, I haven't
had a slippage issue on my Spectro S7 hubs, though I have torn the
flats out of the tabbed washers under heavy pedal loads.

I milled a special anti-turn washer from solid 12L14 steel for the
left side of my Spectro-equipped 29er.

Chalo