Trikes much slower than bikes? Why?

Tim Olson said:

In a recent posting to the bentrideronline trike forum, someone said
that a 200 km brevet took them 10 hours, 20 min on a Trice trike, while
a similar ride took 7 hours, 16 min on a Bacchetta Aero. Although he
mentioned that the course was more hilly on the trike ride, that's 42%
slower. Someone else responded saying that they were seeing 5-6 mph
reduction in speed on a Catrike Road vs their normal recument. Assuming
they are normally riding 15-20mph, that's 25-33% slower, as well.

So what could be causing that much performance loss on a trike (and can
it be corrected)? Obviously there is a bit more rolling resistance with
3 tires instead of 2, but rolling resistance shouldn't be that large a
fraction of the total energy expenditure. I would think that the
aerodynamics of a low, reclined trike would be equal or exceed that of a
standard LWB or SWB recumbent. Could it be losses due to the toe-in
required on the front wheels?

A combination of all of the above plus the extra weight, and maybe some
power loss due to lower torsional rigidity.

--
Tom Sherman - Earth

Tim Olson said:

In a recent posting to the bentrideronline trike forum, someone said
that a 200 km brevet took them 10 hours, 20 min on a Trice trike,

while

Quoted message said:

a similar ride took 7 hours, 16 min on a Bacchetta Aero. Although he

Quoted message said:

mentioned that the course was more hilly on the trike ride, that's

42%

Quoted message said:

slower. Someone else responded saying that they were seeing 5-6 mph
reduction in speed on a Catrike Road vs their normal recument.

Assuming

Quoted message said:

they are normally riding 15-20mph, that's 25-33% slower, as well.

So what could be causing that much performance loss on a trike (and

can

Quoted message said:

it be corrected)? Obviously there is a bit more rolling resistance

with

Quoted message said:

3 tires instead of 2, but rolling resistance shouldn't be that large

a

Quoted message said:

fraction of the total energy expenditure. I would think that the
aerodynamics of a low, reclined trike would be equal or exceed that

of a

Quoted message said:

standard LWB or SWB recumbent. Could it be losses due to the toe-in
required on the front wheels?

-- Tim Olson
RANS V-rex rider considering a trike, as well...

I am the one who posted the 200 km brevet report the BROL trike forum
and here as well. Trikes are slower than a bike of equivalent seat
angle and bottom bracket height for a variety of reaons including:

1. Greater aerodynamic drag from the wheels and associated mounting and
steering hardware to each side of the rider. Also most trikes have a
USS hand position that puts the riders arms into a position of greater
frontal area than the Bacchetta Aero I had the much faster 200 km time
on. Also note my Trice XXL has front mudguards which are right out
there in the airflow scooping air while my Aero doesn't have mudguards.
I ride the trike when the roads are wet such as on the recent 200 km
brevet and I ride the Aero if the roads are dry and speed is an issue.

2. Greater weight due to more material on the frame and in the steering
system to support two front wheels plus the frame and wheels need to be
built stronger to support the high lateral loads a trike places on
them when cornering. The third wheel also adds weight.

3. Increased rolling resistance both from using smaller diameter wheels
(three 406mm wheels on the Trice XXL vs. two 571mm wheels on the
Bacchetta Aero) and due to tyre scrub from steering corrections and
minor front wheel alignment changes that occur while making steering
inputs and hitting bumps.

4. Less efficient drivetrains. My Trice XXL has a total of three chain
tubes. They are Teflon and low drag but still have more drag than the
Aero which doesn't have any chain tubes. Many small wheeled trikes also
use internal gearing devices to get reasonable gear range. My Trice XXL
doesn't have any internal gearing using a Shimano Capreo hub instead.
However I believe the drivetrain losses are higher on the 9, 10 and 11
tooth cogs than on the larger cogs normally used on a larger wheeled
bike.

I think trikes are great for rides where stability is important such as
riding at night where road hazards are more difficult to see and riding
in wet or icy conditions. Also not having to clip and unclip at stops
is convenient and allows a faster get away when the light turns green
and with no need to balance one can go as slow as they want with a
heavy touring load. When speed is a factor though such as club rides
and faster transportational rides plus long distance events I'll take
the greater efficiency of a good high performance bike unless the road
conditions are likely to have traction hazards in which case I'd rather
be on the bike and upright than on a faster bike falling down due to
loss of traction. All recumbents are compromises and I consider them
different tools for different jobs.

Zach Kaplan

Zach,

Good points here. I was wondering if building a 3/4 full fairing for a
trike (head outside) would mitigate some of these issues. I've ridden
fully faired single-track recumbents and they are very fast, but I
wouldn't feel secure on the roads with them. A trike might be the
trick (i.e. a velomobile).

What sort of times are folks getting with 'velomobiles' like these:

http://www.velomobiles.net/comvm.html

I'm particularly impressed by the Versatile Velomobile by Flevobike.
Thanks,

Bill

BikingBill said:

What sort of times are folks getting with 'velomobiles' like these:

http://www.velomobiles.net/comvm.html

I'm particularly impressed by the Versatile Velomobile by Flevobike.
Thanks,

Bill

Bill:

John Williams has the only Quest velomobile in the U.S. He'll be at the
Jack Frost time trial in a couple weeks. After that, we should know how
fast it is on flat ground.

John's very fast, but he was struck low by course conditions at the
Wasco Wild West 75: http://www.ohpv.org/wasco2004/index.htm

Jeff

BikingBill said:

Good points here. I was wondering if building a 3/4 full fairing for a
trike (head outside) would mitigate some of these issues. I've ridden
fully faired single-track recumbents and they are very fast, but I
wouldn't feel secure on the roads with them. A trike might be the
trick (i.e. a velomobile).

Note that the 861 mile UK End to End course record is held on a fully
faired trike (a Windcheetah). As Zach said, it's horses for courses,
and a trike /can/ go fast even if they're not going to do the maximum
business at Battle Mountain.
See http://www.windcheetah.co.uk/record.htm

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Zach said:

I am the one who posted the 200 km brevet report the BROL trike forum
and here as well. Trikes are slower than a bike of equivalent seat
angle and bottom bracket height for a variety of reaons including:

1. Greater aerodynamic drag from the wheels and associated mounting

and

Quoted message said:

steering hardware to each side of the rider. [...]
2. Greater weight [...]
3. Increased rolling resistance both from using smaller diameter

wheels

Quoted message said:

(three 406mm wheels on the Trice XXL vs. two 571mm wheels on the
Bacchetta Aero) and due to tyre scrub from steering corrections and
minor front wheel alignment changes that occur while making steering
inputs and hitting bumps.

4. Less efficient drivetrains.

A local Velomobile builder thinks that tire scrub issue under #3 is a
big issue. I bet if you controlled all the other variables, a bike
would still be faster. Trikes have their place, but bikes are magical.
They are only stable in motion. That seems more philosophical than
logical.

BikingBill said:

What sort of times are folks getting with 'velomobiles' like these:

http://www.velomobiles.net/comvm.html

I suspect that Quest and Mango are the fastest Velomobiles for every day
use. There is a new Leitra Sport fairing coming, which also seems to
have some speed potential as well as enough practicability for riding in
traffic and carrying luggage.
http://www.leitra.dk/

The downside of Velomobiles is their weight penalty uphill.
http://www.liegerad-fernweh.de/503-pbp2003/IMG_3632.jpg

This picture shows a Quest in Paris-Brest-Paris, not the ideal course
für a Velomobile. But on the flats the superior aerodynamics rule. In
this case a Quest is faster than a Lowracer with tailbox, Ymte, the
builder, did about 51 or 52Km/h (31 mph) in a race.

Quoted message said:

I'm particularly impressed by the Versatile Velomobile by Flevobike.

The Versatile ist heavy and expensive, and if you order one today, it
may take two years till you get one. But it looks nice and it seems to
be more sturdy and robust than other quite fragile models.

Kurt

--
*recumbent cartoons*
http:/bikecartoons.de

Kurt Fischer said:

I suspect that Quest and Mango are the fastest Velomobiles for every day
use. There is a new Leitra Sport fairing coming, which also seems to
have some speed potential as well as enough practicability for riding in
traffic and carrying luggage.
http://www.leitra.dk/

ME WANT! ME WANT! ME WANT! ME WANT! ME WANT! 🙂

When reasonable practical fuels cells become available (2007?), they
could be combined with a small assist motor to help with acceleration
and hill climbing, making a very efficient commuter vehicle.

Quoted message said:

The downside of Velomobiles is their weight penalty uphill.
http://www.liegerad-fernweh.de/503-pbp2003/IMG_3632.jpg

This picture shows a Quest in Paris-Brest-Paris, not the ideal course
für a Velomobile. But on the flats the superior aerodynamics rule. In
this case a Quest is faster than a Lowracer with tailbox, Ymte, the
builder, did about 51 or 52Km/h (31 mph) in a race....

Isn't Ymte Sijbrandij about 2 meters tall? If so, the Quest and Mango
are larger and heavier than is optimum for those smaller than the
average Dutchman.

--
Tom Sherman - Earth

Tom Sherman <[email hidden]> wrote:

[Leitra Sport]

Quoted message said:

ME WANT! ME WANT! ME WANT! ME WANT! ME WANT! 🙂

Due to the short wheel-base, the behavior of a Leitra is kind of twitchy
or responsive, so it's recommended to steer it with only a light touch
of your fingertips.

Quoted message said:

When reasonable practical fuels cells become available (2007?), they
could be combined with a small assist motor to help with acceleration
and hill climbing, making a very efficient commuter vehicle.

A good idea could be to build a trailer with integrated assist motor. So
you had a relatively light vehicle in case you don't need an assist and
could attach it only when help really is needed.

Quoted message said:

Isn't Ymte Sijbrandij about 2 meters tall? If so, the Quest and Mango
are larger and heavier than is optimum for those smaller than the
average Dutchman.

Yes, Ymte is tall, but not very heavy. Of course, Quest and Mange could
be built in lighter versions, but the Dutch traditionally go for
reliability and durability. And the outer shell of these two Velomobiles
could be more robust: I know of someone who had to send his Quest in for
repair, because a child climbed on the front nose and damaged it.

It's not very likely that a Quest will be stolen, but my major concern
would be vandalism in cities. And that's another problem with
velomobiles: Where to park it safely?

Kurt

--
*recumbent cartoons*
http://bikecartoons.de

In article <[email hidden]>,
[email hidden] wrote:

| Zach wrote:
| > 3. Increased rolling resistance both from using smaller diameter
| wheels
| > (three 406mm wheels on the Trice XXL vs. two 571mm wheels on the
| > Bacchetta Aero) and due to tyre scrub from steering corrections and
| > minor front wheel alignment changes that occur while making steering
| > inputs and hitting bumps.
|
| A local Velomobile builder thinks that tire scrub issue under #3 is a
| big issue. I bet if you controlled all the other variables, a bike
| would still be faster. Trikes have their place, but bikes are magical.
| They are only stable in motion. That seems more philosophical than
| logical.

Ah, I think I see where the inefficiency is, now:

On a bike, small steering movements cause the front of the bike to
slightly change course, but since a bike can lean, the center of mass of
the rider/bike combo stays pretty much on a straight line, and the lean
that causes brings the front wheel back around (due to front wheel
trail). Thus, the front tire track describes a serpentine trail around
the direct line of travel, but the center of mass remains on that direct
line.

In a (non-leaning) trike, however, small steering movements change the
velocity vector of the center of mass (acceleration), which requires
energy.

So would a leaning trike like those described at:

http://www.geocities.com/rcgilmore3/TiltingTrikes.htm

address this inefficiency?

-- Tim Olson