Re: Small front wheel question

[frkrygow@gmail.com]

On Apr 2, 7:44 am, Veloise <galena3...@mypacks.net> wrote:
> Now that we're past April 1...this is really a question for Sheldon
> (RIP).
>
> I have a Counterpoint tandem (the original, not a Viewpoint). Spec
> sheets from later years indicate that the max weight on the front
> should be about 175 lbs, and total gross vehicle weight 400.
>
> New friend in my life. To fit under that total limitation, I would
> have to have a couple legs removed.
>
> Need advice from a Sheldon wannabe (um, other than the obvious) who
> has real life practical experience with 'bents and other small
> wheels.
>
> Here are pics of the bike. I don't have the specs memorized but they
> are easy enough to type in from a trip to my basement.http://home.earthlink.net/~veloise/cpoint.htm
>
> TIA!

Well, my small wheel experience is mostly limited to folding bikes.
So if you don't mind some speculation... (Of course, if you _did_ mind
speculation, you wouldn't post on rec.bicycles!)

First, small wheels are significantly stronger than large wheels, if
spoke count, spoke gages, rim cross section etc. are equal. I'd be
surprised if the wheel itself gave problems in normal riding. If it
were to fail, I'd expect it would be in walking-speed turns, when you
tend to use the front wheel to muscle the bike around to keep
balance. That's the only time I've broken a spoke (a front one) with
our conventional tandem. What I'm getting at is that even if the
front wheel collapsed, it would happen at maybe 2 mph.

For slow speed, out-of-balance "S" turns, you might be putting
considerable torsion into the frame. I'd try to keep away from super-
slow speed "S" turns. Start off briskly and straight. Keep the
weight centered to reduce spoke stress and frame stress.

But it looks like the design must really load the headset bearings and
the front wheel bearings, as well as the front tire. It may be that
the stated weight limits are based on getting acceptable life out of
those things. Overloading a bearing really shortens it's life. (It's
a cubic relationship - that is, double the load gives one eighth the
life.) The good news is those are replaceable components, and they
don't usually fail catastrophically.

Overall, I'd be inclined to give it a try and keep a close eye on
things. I'd start with short rides and build up, but I'd do frequent
inspections for as long as you owned the bike.

One final comment: your questions are much better discussed on
rec.bicycles.tech, so I'm copying this to that forum, too.

- Frank Krygowski

[Andreas Oehler]

Wed, 2 Apr 2008 08:29:23 -0700 (PDT), frkrygow@gmail.com:

>On Apr 2, 7:44 am, Veloise <galena3...@mypacks.net> wrote:

>> I have a Counterpoint tandem (the original, not a Viewpoint). Spec
>> sheets from later years indicate that the max weight on the front
>> should be about 175 lbs, and total gross vehicle weight 400.
>>
>> New friend in my life. To fit under that total limitation, I would
>> have to have a couple legs removed.
>>
>> Need advice from a Sheldon wannabe (um, other than the obvious) who
>> has real life practical experience with 'bents and other small
>> wheels.


I don't have experience with a Couterpoint, but we own a Hase Pino, which
is a very similar tandem with a 20" front wheel:

http://velo.dyndns.eu/bilder/pino3-kl.jpg
http://velo.dyndns.eu/bilder/pino4-kl.jpg

I built the wheels myself. The most important thing is a good
wheelbuilding with high spoke tension and good quality components. To cope
with the high load use the widest available tire and the widest available
rim. In our case we bought a Maxxis Hookworm tire 53-406 (53mm wide),
which is heavy but nearly indestructable. The rim is a Alex DM24 (24mm
inner width) - don't use a narrower rim, because a wide tire on a too
narrow rim with such a heavy load will result in poor cornering.
The wheel is build around a SON20-disc hub dynamo with 36 spoke holes for
6-hole brake disc in tandem version. This is a very robust hub with
allowance to be used on a tandem. Without a disc brake any good quality 36
hole hub will do - maybe Shimano XT or similar. I used strait 2mm spokes
by DT - but any other fair quality stainless steal spoke will be OK.

The bigger problem is braking. When travelling with the tandem (4 big
panniers) we reach over 200kg total wheight and braking hard down some
medium hills in the black forest kills the front disc (180mm diameter,
Magura): It was faultless on top of the hill but has a permanent "wave" in
it down in the valley...

I fitted a third brake (rim brake on the 26" back wheel with heavy rim,
activated by a bar end switcher) than for this kind of long braking to
share the heat. I don't think it would be wise to use the Counterpoint
Tandem heavy loaded with just rim brakes in mountainous terrain. At least
some kind of "drag brake" on the rear hub should be added. It is possible
to overheat rims/tires on long descends with just a single person on a
bike with 700c wheels. It would be stupid to try the same with double the
wheigt but a smaller front wheel!

>First, small wheels are significantly stronger than large wheels, if
>spoke count, spoke gages, rim cross section etc. are equal.

This is true. But with this kind of tandems there is realy a lot of load
on the front wheel. Also the front rim brake is able to dump immense
amounts of heat into the metal without lifting the rear wheel. So a heavy
wide rim with a deep profile is recommended. The front tire also have to
cope with the load, the braking forces and the brake heat - so something
heavier is better than a skinny racing tire... Tire and rim should allow
high pressure.

Andreas

[Tom Sherman]

Andreas Oehler wrote:
> Wed, 2 Apr 2008 08:29:23 -0700 (PDT), frkrygow@gmail.com:
>
>> On Apr 2, 7:44 am, Veloise <galena3...@mypacks.net> wrote:
>
>>> I have a Counterpoint tandem (the original, not a Viewpoint). Spec
>>> sheets from later years indicate that the max weight on the front
>>> should be about 175 lbs, and total gross vehicle weight 400.
>>>
>>> New friend in my life. To fit under that total limitation, I would
>>> have to have a couple legs removed.
>>>
>>> Need advice from a Sheldon wannabe (um, other than the obvious) who
>>> has real life practical experience with 'bents and other small
>>> wheels.
>
>
> I don't have experience with a Couterpoint, but we own a Hase Pino, which
> is a very similar tandem with a 20" front wheel:
>
> http://velo.dyndns.eu/bilder/pino3-kl.jpg
> http://velo.dyndns.eu/bilder/pino4-kl.jpg
>
> I built the wheels myself. The most important thing is a good
> wheelbuilding with high spoke tension and good quality components. To cope
> with the high load use the widest available tire and the widest available
> rim. In our case we bought a Maxxis Hookworm tire 53-406 (53mm wide),
> which is heavy but nearly indestructable. The rim is a Alex DM24 (24mm
> inner width) - don't use a narrower rim, because a wide tire on a too
> narrow rim with such a heavy load will result in poor cornering.
> The wheel is build around a SON20-disc hub dynamo with 36 spoke holes for
> 6-hole brake disc in tandem version. This is a very robust hub with
> allowance to be used on a tandem. Without a disc brake any good quality 36
> hole hub will do - maybe Shimano XT or similar. I used strait 2mm spokes
> by DT - but any other fair quality stainless steal spoke will be OK.
>
> The bigger problem is braking. When travelling with the tandem (4 big
> panniers) we reach over 200kg total wheight and braking hard down some
> medium hills in the black forest kills the front disc (180mm diameter,
> Magura): It was faultless on top of the hill but has a permanent "wave" in
> it down in the valley...
>
> I fitted a third brake (rim brake on the 26" back wheel with heavy rim,
> activated by a bar end switcher) than for this kind of long braking to
> share the heat. I don't think it would be wise to use the Counterpoint
> Tandem heavy loaded with just rim brakes in mountainous terrain. At least
> some kind of "drag brake" on the rear hub should be added. It is possible
> to overheat rims/tires on long descends with just a single person on a
> bike with 700c wheels. It would be stupid to try the same with double the
> wheigt but a smaller front wheel!
>
>> First, small wheels are significantly stronger than large wheels, if
>> spoke count, spoke gages, rim cross section etc. are equal.
>
> This is true. But with this kind of tandems there is realy a lot of load
> on the front wheel. Also the front rim brake is able to dump immense
> amounts of heat into the metal without lifting the rear wheel. So a heavy
> wide rim with a deep profile is recommended. The front tire also have to
> cope with the load, the braking forces and the brake heat - so something
> heavier is better than a skinny racing tire... Tire and rim should allow
> high pressure.
>
Another option would be to build the front wheel around an Arai drag
brake and have it operated by a bar-end, and also have the regular rim
brake. Green Gear (aka Bike Friday) has build some of their tandems this
way.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

[Doug Milliken]

> >>> I have a Counterpoint tandem (the original, not a Viewpoint). Spec
> >>> sheets from later years indicate that the max weight on the front
> >>> should be about 175 lbs, and total gross vehicle weight 400.
> >>>
> >>> New friend in my life. To fit under that total limitation, I would
> >>> have to have a couple legs removed.
> >>>

Why not call up Angle Lake in Seattle/Tacoma, they were the Counterpoint
dealers for many years.
Used to be at 206-878-7457

[Veloise]

Doug wrote:

> Why not call up Angle Lake in Seattle/Tacoma, they were the Counterpoint
> dealers for many years.
> Used to be at 206-878-7457

That may be. The person handling CP, Kelvin, moved to Colorado, and CP
distributorship moved too. Then the lawsuit happened, time passed,
Bilenky bought the patent and started making Viewpoints. (Midwest
Tandem Rally 1997.) Bilenky used to provide an incredibly low-
trafficked owners' forum, which is where I found my used bike several
months after it was listed for sale.

See my post from a couple days ago. I really doubt that Whoever
Answers The Phone at a LBS would be of much help. (Their website is
remarkably devoid of content at of this posting. http://www.anglelake.com/index.html)

A little googling turns up many references to presentations at
adaptive recreation meetings and Jim Weaver as though he's still as
active with it as in the 80's. My own website is probably the most
extensive resource for the bike (I am serious about acting as a
switchboard for buyers and sellers). What I'm looking for is
recommendations on front wheel designs.

HTH

--Karen D.

[Andreas Oehler]

Wed, 9 Apr 2008 04:43:51 -0700 (PDT), Veloise:

> What I'm looking for is
>recommendations on front wheel designs.

You didn't comment on the hints you got so far...

Andreas

[Veloise]

Andreas wrote:

> You didn't comment on the hints you got so far...

Did too. April 8.

--Karen "reading comprehension" D.

[Michael Press]

In article
<e942c18d-0093-4dec-a85c-2243804719da@t54g2000hsg.googlegroups.com>,
Veloise <galena3066@mypacks.net> wrote:

> Andreas wrote:
>
> > You didn't comment on the hints you got so far...
>
> Did too. April 8.
>
> --Karen "reading comprehension" D.

The thread was cross posted to rbt in its middle,
and your 8 April message did not appear in rbt.

--
Michael Press