HOW TO RACE PREP YOUR ON-ROAD BIKE
KEEP THE BRAKE DISC FROM
BINDING
APPLIES TO: SB5
The floating front brake rotor in the SB5’s optional
(though I call it a “must-have”) brake kit can tend to float
a little too much. If it binds the brakes when laid down
on the right side, your turning speed will be severely
compromised. Fashion a brake retainer from some piano
wire using a couple of pairs of needle-nose pliers to keep
the rotor from binding. It will take some trial and error to
get the bends just right, but the trouble is well worth it.
Make sure it clears the wheel pins and don’t let a sharp
edge of the wire contact the rotor so you don’t end up
wearing a groove in the rotor face.
USE YOUR SLIPPER CLUTCH
The slipper clutch is still a fairly new development in the world of RC bikes. It gives you
the ability to get on the throttle earlier coming out of a turn without the fear of pulling a
wheelstand. Spectators love wheelies, but when you wheelie during a race, you have
no directional control and risk flipping the bike over. If you set the slipper too loose, you
can overheat and potentially melt the clutch and spur gear. If it’s too tight, you lose the
benefit of having a slipper altogether. First, get it in the ballpark during open practice,
then do a fine-tuning on the track right before you get on the drivers’ stand, especially
if the traction or temperature changes over the course of the day. Keep a box wrench
in your pocket and do a couple of test passes, tightening or loosening in 1/16-turn
increments—it’s pretty sensitive. You can also change the sensitivity by replacing the
stock clutch spring with Belleville washers. I like my clutch to slip for between 4-8 feet,
depending on the traction available and the power of the motor I’m using. Torquier
motors will still raise the front wheel of the bike even after the clutch fully engages, so
APPLIES TO: ALL
A common mistake for beginners is to set the chain tension too tight. When the chain is
run tight, it will bog down the motor and prematurely wear the sprockets, and axle and
layshaft bearings. The stock Thunder Tiger and even the aftermarket Alleven RC chains
don’t stretch at all, so there isn’t even a break-in period to worry about. The chain should
seem fairly loose when on the bench, even dropping up to 1/4 inch. As long as it doesn’t
skip off the sprockets, it’s good, even if it touches the swingarm when at rest. However,
drive belts, as used on the Thunder Tiger SB5, are another story—it should be run tight
as possible. The belt will stretch progressively during the first dozen runs, so you will
have to change the included axle adjuster inserts a few times to chase the proper belt
tension. You’ll know the belt is slipping if you hear a ratcheting sound coming from the
bike under hard acceleration. When you’ve reached the limits of the adjusters, your
options are to install a new belt (annoying and can get expensive), make a tensioner with
some spare parts, or purchase ZH Racing’s replacement carbon swingarm plate with a
built-in tensioner. Although I’ve made plenty of tensioners myself for cars and buggies, I
personally use the ZH Racing option.
DXR500 tip
The side pipe adds a nice
touch of realism to the
DXR500’s bodywork, but
you have to unscrew the
mount every time you
want to take off the seat/
tank/rider assembly. Use
a 3x12mm screw to move
the pipe hanger to the tail
frame instead of mounting
it to the bodywork.
Running a bike on the track for the first time can be
a handful, but hopefully, these tips make you better
prepared to make a good showing. On the track, where
there are solid objects to smack into, the stakes are
higher than running in an open parking lot, so preparation
is key. Now go out there and show the people who’ve
never even seen an RC bike in person how they can
perform, and hopefully, you can plant some interest in
others to help grow this overlooked segment of the RC
world.
SOURCES
Alleven RC, distributed by 2WheelHobbies
2wheelhobbies.com
Du-Bro dubro.com
Duratrax duratrax.com
Thunder Tiger Racing ttamerica.com
ZH Racing, distributed by 2WheelHobbies
2wheelhobbies.com
