C y c l i s t Recumbent - Steve Briggs

My Bike: A Long Wheelbase
Mid-Racer
I’ve been working on designing bikes that
serve as comfortable commuters, yet are
fast and fun. They seemed to be improving
nicely over the years — until I entered a
recumbent race with my friend, Jay Hoover,
and ended up mid-pack in the unfaired class!
This is the worst I’ve ever done in unfaired
HPV (Human Powered Vehicle) racing, and
something had to be done about it. All of the
hot rods in that race had real laid-back seats,
so I started slapping together and modifying
experimental laid-back seats on my test bikes.
Lowracers seem to be the fastest of the
unfaired bikes. However, I worry about the
safety of lowracers on the road, because motorists
who can see curbs and lines on the road
just fine seem to develop a blind spot when it
comes to bicycles three feet taller than this.
Highracers seem just a tick slower on the
track, though I suspect they might be faster in
the real world. These seem too high up to me
— it’s a long way to fall, and the high bottom
bracket (BB) can make it hard to get started
from a stop, especially up hill.
For my next test bike, I used the aerodynamic
rider position of those two types of
bikes, but set the rider height part way between
the two. I built mine as a long wheelbase
(LWB) because, well, I like them. There’s
nothing better for a long ride. In the past I’ve
built several LWBs with low head tube angles
and direct steering, using lightweight, high
performance 16” front wheels. After a lot of
messing with that fork rake and handlebars,
I’ve come to the conclusion that these just
don’t track as steadily as 20” wheels. Not that
it’s unsafe; you just have to pay a little more
attention to keep the thing pointed where you
want it to go.
By Charles Brown
LWBs tend to have a problem with the front
wheel slipping out when a patch of sand or
gravel jumps in front of you unexpectedly. The
mid-racer layout, with its higher BB, allows
the front wheel to be moved farther back so
you can load more weight on it. It then does a
better job of staying put.
With these laid-back seats, some writers
have suggested starting out with them set more
upright, then gradually adjusting them back as
you get used to the position. I couldn’t agree
more! It’s taking me quite a while to get used
to it.
Some years ago, RCN’s Bob Bryant, suggested
that a laid back seat might reduce “recumbent
butt.” (Placing more weight on your
back in the more reclined position places less
weight on your butt.) This certainly seems to
be the case.
The larger seat surface area seems to increase
comfort. Mine is made of plywood with
1/2” Styrofoam on top, with a piece of vinyl
over that, and it’s quite comfortable. These
seats make it impossible to turn around and
see behind you, so a rearview mirror is necessary.
I like narrower handlebars because, when
done right, they permit better one-handed
steering for signaling turns, carrying stuff, etc.
When combined with shallow steering angles,
mine seems to work better with less trail (Trail
is the horizontal distance between the center
of the tire contact patch on the ground and the
intersection of the steering axis with the
ground.) than you’d use with wider handlebars.
Watch out for front wheel/pedal interference!
With the laid-back steering angle and
long wheelbase, the front wheel swings around
quite a bit.
One of my favorite features of this bike is
that it is easier to control when it starts to skid
as compared with your average production
LWB recumbent. This is a subject I’ve studied
a lot. If you are using 406 mm 20” front
and 700c rear wheels, my recommendation
would be to try to design 40% of the weight
on the front wheel, and make the front tire significantly
narrower than the rear.
My other favorite attribute of this bike is
speed. On my old commuter recumbent, which
is no slouch, it took me 23 minutes to get 6.5
miles to work. With the new bike it takes a
consistent 21 minutes with the same effort.
That’s 8% faster, with stops and all! It must be
10-12% faster on the straight-away.
I think this is a really good design and I invite
homebuilders and manufacturers to use
what they can from it. Imagine the speed of a
lowracer combined with the steadiness and ride
of a long-wheelbase! Mine is a lot of fun to
ride. ◆
28 Recumbent Cyclist News