Single speed cranks?

lemmiwinks.au@gmail.com

I'm after a 39T single speed crankset to go with my Nexus Inter8 hub
the LBS is building up for me. They offered the Shimano recommended
crankset (@$170) which includes outboard bearings. I'm somewhat of a
luddite (I've only just installed a cartridge bottom bracket to trial)
and apart from the excessive cost I just don't like the sound of this
newfangled outboard bearing nonsense.

Can anyone advise me of some plain-Jane square taper 170mm single
speed cranks preferably with a 39T chainring? Doesn't have to be
online, but online is ok, a brand name that I can give to the LBS
would do (though they are very much like the Soup Nazi (http://
en.wikipedia.org/wiki/Soup_Nazi) in there so I'm almost afraid to ask).

Joel Mayes

On 2007-10-29, lemmiwinks.au@gmail.com <lemmiwinks.au@gmail.com> wrote:
> I'm after a 39T single speed crankset to go with my Nexus Inter8 hub
> the LBS is building up for me. They offered the Shimano recommended
> crankset (@$170) which includes outboard bearings. I'm somewhat of a
> luddite (I've only just installed a cartridge bottom bracket to trial)
> and apart from the excessive cost I just don't like the sound of this
> newfangled outboard bearing nonsense.
>
> Can anyone advise me of some plain-Jane square taper 170mm single
> speed cranks preferably with a 39T chainring? Doesn't have to be
> online, but online is ok, a brand name that I can give to the LBS
> would do (though they are very much like the Soup Nazi (http://
> en.wikipedia.org/wiki/Soup_Nazi) in there so I'm almost afraid to ask).

Any old road cranks with replacable chainrings can be converted to SS
easily. These are easy to find (your local bicycle recycle place will
certainly have some). All you'll need then is a set of short chainring
bolts and an appropriate chain ring.

Cheers

Joel

--
Human Powered Cycles | High quality servicing and repairs
joel@humanpowered.com.au | Affordable second hand bikes
(03) 9029 6504 | Bicycle reuse centre
www.humanpowered.com.au | Mechanical and on-road training and instruction

BT Humble

lemmiwinks wrote:
> Can anyone advise me of some plain-Jane square taper 170mm single
> speed cranks preferably with a 39T chainring?

I'll have a look in my "crank box" on the weekend...


BTH

lemmiwinks.au@gmail.com

On Oct 29, 3:41 pm, BT Humble <bt_hum...@bigpond.com> wrote:
> lemmiwinks wrote:
> > Can anyone advise me of some plain-Jane square taper 170mm single
> > speed cranks preferably with a 39T chainring?
>
> I'll have a look in my "crank box" on the weekend...
>
> BTH

Ta. I just realised I've got some worn out Shimano Biopace cranks
that could be pressed into service except the biopace rings are
elliptical (only the middle ring is worn out) so probably not good for
hub gears. I tried to get a replacement chainring from the LBS when
it wore out but they baffled me with BCD figures and generally didn't
want to help (I still consider this preferable to the thinly veiled
hostility they normally exhibit).

John Henderson

lemmiwinks.au@gmail.com wrote:

> Ta. I just realised I've got some worn out Shimano Biopace
> cranks that could be pressed into service except the biopace
> rings are elliptical (only the middle ring is worn out) so
> probably not good for hub gears. I tried to get a replacement
> chainring from the LBS when it wore out but they baffled me
> with BCD figures and generally didn't want to help (I still
> consider this preferable to the thinly veiled hostility they
> normally exhibit).

You need to know the BCD figure to be able to buy a chainring
which will fit. See
http://www.sheldonbrown.com/gloss_bo-z.html#bcd for info on how
to measure it.

Then you should be able to buy a round 39T chainwheel to fit
your cranks.

It'll be worth making sure you've got a bottom bracket of the
right length to get "perfect" chainline (no sideways
deflection, front to rear). In this respect, you'll be setting
the chainline up as if it were a single speed. See
http://www.sheldonbrown.com/chainline.html

John

TimC

On 2007-10-29, lemmiwinks.au@gmail.com (aka Bruce)
was almost, but not quite, entirely unlike tea:
> On Oct 29, 3:41 pm, BT Humble <bt_hum...@bigpond.com> wrote:
>> lemmiwinks wrote:
>> > Can anyone advise me of some plain-Jane square taper 170mm single
>> > speed cranks preferably with a 39T chainring?
>>
>> I'll have a look in my "crank box" on the weekend...
>
> Ta. I just realised I've got some worn out Shimano Biopace cranks
> that could be pressed into service except the biopace rings are
> elliptical (only the middle ring is worn out) so probably not good for
> hub gears.

Why not? The chainline stays under the same tension.

--
TimC
Can't open /usr/share/games/fortunes/fortunes. Lid stuck on cookie jar.

John Henderson

TimC wrote:

> Why not? The chainline stays under the same tension.

From my observation of Biopace chainrings in use, that's what I
thought too, but wasn't confident enough to say it.

Sheldon Brown does report using Biopace on a fixed-gear bike:
http://sheldonbrown.com/biopace.html

John

BT Humble

John Henderson wrote:
> TimC wrote:
> > Why not? The chainline stays under the same tension.
>
> From my observation of Biopace chainrings in use, that's what I
> thought too, but wasn't confident enough to say it.
>
> Sheldon Brown does report using Biopace on a fixed-gear bike:http://sheldonbrown.com/biopace.html

He certainly seems a bit of a "true believer" in Biopace chainrings.
The phrase "With all the zeal of a convert" springs to mind, for some
reason. ;-)

I'm sure they're very nice, mind you. Do you need to use a long-reach
front derailleur with them, or is varience in radius relatively small?


BTH

flyingdutch

you'll need something at least vaguely built for the job.

Preferably running a tougher chain. IE track or BMX chain.
That means perferably a thicker toothed chainring. Anything less will struggle and possibly wear and/or snap

The Alfine chainset that the LBS is recommending is rather good and a steal at that price IMHO.

lemmiwinks.au@gmail.com

On Oct 29, 4:13 pm, John Henderson <jhenRemoveT...@talk21.com> wrote:
> lemmiwinks...@gmail.com wrote:
> > Ta. I just realised I've got some worn out Shimano Biopace
> > cranks that could be pressed into service except the biopace
> > rings are elliptical (only the middle ring is worn out) so
> > probably not good for hub gears. I tried to get a replacement
> > chainring from the LBS when it wore out but they baffled me
> > with BCD figures and generally didn't want to help (I still
> > consider this preferable to the thinly veiled hostility they
> > normally exhibit).
>
> You need to know the BCD figure to be able to buy a chainring
> which will fit. Seehttp://www.sheldonbrown.com/gloss_bo-z.html#bcdfor info on how
> to measure it.
>
> Then you should be able to buy a round 39T chainwheel to fit
> your cranks.

I did some googling and turned up Sheldon's article on measuring BCD
but I haven't had a chance to check my chainrings as yet.

> It'll be worth making sure you've got a bottom bracket of the
> right length to get "perfect" chainline (no sideways
> deflection, front to rear). In this respect, you'll be setting
> the chainline up as if it were a single speed. Seehttp://www.sheldonbrown.com/chainline.html
>
> John

I'm slightly concerned about chainline as I just installed a cartridge
BB to try and it's 122mm. It's a roadbike but I'm currently running a
MTB triple. I figure if I need a shorter spindle length I'll buy a
new cartridge BB and put the 122mm in my MTB which is in pretty dire
need of either a rebuild of the cup and cone BB or a replacement.

lemmiwinks.au@gmail.com

On Oct 29, 7:15 pm, TimC <tconn...@no.spam.accepted.here-
astro.swin.edu.au> wrote:
> On 2007-10-29, lemmiwinks...@gmail.com (aka Bruce)
> was almost, but not quite, entirely unlike tea:
>
> > On Oct 29, 3:41 pm, BT Humble <bt_hum...@bigpond.com> wrote:
> >> lemmiwinks wrote:
> >> > Can anyone advise me of some plain-Jane square taper 170mm single
> >> > speed cranks preferably with a 39T chainring?
>
> >> I'll have a look in my "crank box" on the weekend...
>
> > Ta. I just realised I've got some worn out Shimano Biopace cranks
> > that could be pressed into service except the biopace rings are
> > elliptical (only the middle ring is worn out) so probably not good for
> > hub gears.
>
> Why not? The chainline stays under the same tension.

Does it? Ok, I'd assumed it wouldn't, but I'd not put much thought or
examination of the chainrings into that assumption.

lemmiwinks.au@gmail.com

On Oct 30, 6:37 am, John Henderson <jhenRemoveT...@talk21.com> wrote:
> TimC wrote:
> > Why not? The chainline stays under the same tension.
>
> From my observation of Biopace chainrings in use, that's what I
> thought too, but wasn't confident enough to say it.
>
> Sheldon Brown does report using Biopace on a fixed-gear bike:http://sheldonbrown.com/biopace.html
>
> John

The LBS told me that Biopace chainrings were no longer available when
I tried to get a new one about 18 months ago. However I'd just be
happy with a chainring that fits, biopace or not.

lemmiwinks.au@gmail.com

On Oct 30, 8:29 am, BT Humble <bt_hum...@bigpond.com> wrote:
> I'm sure they're very nice, mind you. Do you need to use a long-reach
> front derailleur with them, or is varience in radius relatively small?
>
> BTH

There was nothing fancy about the derailleur on the bike they came off
(that I noticed).

lemmiwinks.au@gmail.com

On Oct 29, 2:24 pm, Joel Mayes <j.ma...@invalid.invalid> wrote:

> Any old road cranks with replacable chainrings can be converted to SS
> easily. These are easy to find (your local bicycle recycle place will
> certainly have some). All you'll need then is a set of short chainring
> bolts and an appropriate chain ring.

The only bicycle recycle place is the shop at the tip (I got a nice
lugged steel roadie for $15) but it's probably worth checking out.