large wheels on trikes

What are the pros and cons of having larger drive wheels on tadpole trikes.
The builder I am writing to said there are arguments both ways but I have
not gotten his examples yet.

If there are no reasons not to I would like to change the 20" wheel for a 26
just to get the small increase in speed.

my news wrote:
What are the pros and cons of having larger drive wheels on tadpole
trikes. The builder I am writing to said there are arguments both
ways but I have not gotten his examples yet.

If there are no reasons not to I would like to change the 20" wheel
for a 26 just to get the small increase in speed.

Pro:

o easier to get high gears with standard components
o /possibly/ slightly lower rolling resistance

Con:

o wheel less resistant to lateral forces
o have to carry two different sizes of spare tube
o harder to get low gears with standard components

My trike has 406s all round.

--
Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
It would appear apparent, to me at least, that dinosaurs were largely
burrowing creatures.

On Thu, 21 Jul 2005 10:28:18 +0100, "Dave Larrington"
wrote:

my news wrote:
What are the pros and cons of having larger drive wheels on tadpole
trikes. The builder I am writing to said there are arguments both
ways but I have not gotten his examples yet.

If there are no reasons not to I would like to change the 20" wheel
for a 26 just to get the small increase in speed.

Pro:

o easier to get high gears with standard components
o /possibly/ slightly lower rolling resistance

Con:

o wheel less resistant to lateral forces
o have to carry two different sizes of spare tube
o harder to get low gears with standard components

My trike has 406s all round.

To this I would add a better ride with larger wheels. Yes, I am well
aware frame design has a major influence on this, but my 24" and 26"
trikes are smoother riding, and this contribute to their being faster
than the 16/20 and 20/20 trike that I had before.By fast, I mean easy
cruising in the high teens/low twenties.

Dave Larrington wrote:
my news wrote:
What are the pros and cons of having larger drive wheels on tadpole
trikes. The builder I am writing to said there are arguments both
ways but I have not gotten his examples yet.

If there are no reasons not to I would like to change the 20" wheel
for a 26 just to get the small increase in speed.

Pro:

o easier to get high gears with standard components
o /possibly/ slightly lower rolling resistance

Con:

o wheel less resistant to lateral forces
o have to carry two different sizes of spare tube
o harder to get low gears with standard components

My trike has 406s all round.

One other disadvantage of a large rear wheel on a trike is it requires
the rear axle to be moved further behind the seat thus reducing the
weight on the drive wheel and making the wheel more likely to spin on
loose or slippery surfaces. Moving the rear axle back and lengthening
the wheelbase does increase high speed stability though.

My trikes have either 406s all round or 349s all round. They get enough
wheel spin on wet climbs that I wouldn't want the rear axle further
back. I also don't like carrying multiple sizes of spare tubes.

Zach

"Dave Larrington" writes:

Pro [for 26 inch rear wheel]:

o easier to get high gears with standard components

Pro for 20 inch rear wheel:

o easier to get smaller gears with standard components :-)

--
Simon Kellett, Darmstadt, Germany | http://home.arcor.de/zoxed
Hase Kettwiesel trike | ex-Pashley PDQ SWB
Flux V220 CLWB | Zox20 Lowracer