Post by TurbyPost by RonI know there a lots of variable in terms of road course and vehicle
specifics, but on a fairly tight road course, would a roadrace sidecar rig
be competitive against a motorcycle? I suspect the greater contact patch of
the sidecar rig would allow substantially higher cornering speeds, but the
two wheeler would enjoy greater acceleration and perhaps have more latitude
in picking the fastest line through a curve. Did not look to terribly hard
on teh interwebs, but I did not find any lap time comparisons between
sidecar and single track vehicles. Just curious....
Is our resident sidecar racer still around?
AIR, the addition of as little as 10lbs of rider weight is worth 1 hp.
(I don't remember the exact number, but it's pretty small.) When you
consider that sidecar racers add another person besides the weight of
the hack with basically the same engine, it's hard to imagine them
doing the same laptimes.
--
Turby the Turbosurfer
I assume you were writing about me. I haven't seen any other sidecar
racers in the group.
I race vintage sidecars which are slow even when compared to many
vintage bikes. In the super vintage class we use 750 twins made no
later than 1973 with limited modifications. Horsepower ranges from 45
to 60. Modern rigs run big fours with, I'm guessing here, around 200
hp. For weight my rig goes about 500 lbs while the driver and I each
weigh close to 200. With a total weight of 900 lbs that gives us a
power to weight ratio of 15 to 20 lbs per hp. I doubt a modern rig
has a combined weight under 700 lbs. With 200 hp that gives 3.5 lbs
per hp. Not too shabby but nothing compared to a superbike.
About my weight, at 6' 3" and 190 lbs I'm a size large/long for a
monkey. But that works for us as often as against us. When I hike my
weight out to the side I can keep the chair down till the tires break
loose.
http://tinyurl.com/njhjj
With the back end hung out dirt track style I then shift my weight
around to gain traction.
http://tinyurl.com/pa25n
With a light weight rider they can have problems keeping the chair
down even with the back end hung out.
http://tinyurl.com/rl43e
Turning the opposite direction the passenger moves to the other side
to keep weight on the rear wheel of the bike.
http://tinyurl.com/tj3ju
There are exceptions to that rule though. Here we are going around a
left turn at well over 100 mph. You can almost see daylight under the
rear tire.
http://tinyurl.com/yehzzw
The sidecar tire is trying to roll under from the side force on it,
and the bars are pointed slightly to the right. In this case the
improved aerodynamics of staying tucked in behind the driver is worth
more than improved traction, particularly in high gear. I sometimes
use this position in slower turns so the driver can break the back end
loose if he is having problems with the front end pushing. He
controls the steering but I control the handling. It is a team sport.
In this shot I have pulled back in so the chair will lift, tossing me
over to the other side for the next part of the left, right, left
combo.
http://tinyurl.com/qcvwh
So long as the driver and passenger are on the same page flying the
chair can be fast and fun.
Racing in the rain is a lot more fun on three wheels than two. I've
done both. Here is a shot from my first sidecar race back in '99.
http://tinyurl.com/l84o9
We had practiced in the dry and it started to rain as we headed out to
race.
BTW I bought the rig in 2003 and can drive it, but I have more fun as
passenger. Where else can you drag you shoulder without crashing?
The present driver also does flat track and ice racing in addition to
roadracing solo bikes. He can really throw the rig around which makes
for a fun ride.
To answer the OP question, the fastest solo bikes are faster than any
sidecar, and 4 wheels can be faster than either. The absolute lap
record at the old Loudon track was held by a go-kart, with twin TZ250
engines.
Bruce Richmond