25
setup from track to track. The optional offset hubs, short rear arm setting, (LOSA9854 (0-Degree), LOSA9855 (0.5-Degree), and LOSA9856
(1-Degree)) offer more steering and have been extremely useful on carpet/foam tire racing.
Tuning the Chassis of the JRX-S Type R
Arm Spacing:
The
Type R
has options for changing the wheelbase by moving the front and/or rear suspension arms forward and back.
Moving the .0625” shims in the front or behind the arms changes the wheelbase. A longer wheelbase will provide a smoother feeling setup.
A shorter wheelbase will provide a more aggressive steering setup. In the front the wheelbase has the adjustability of .125”. In the rear the
wheelbase has the adjustability of .0625”. By moving the rear arms forward the car will have more driveshaft angle which gives the car more
traction on-power with more initial off-power steering.
Roll Center:
The roll centers of the
Type R
can be easily adjusted by fl ipping the pivot blocks (that came in the kit) and/or by adding equal
shims under the inner and outer pivots. The stock setup utilizes low roll centers without shims. Testing has shown that low roll centers are best
suited for foam tire racing. A higher roll center will keep the car from rolling (leaning), making the car react faster and have more traction. A
low roll center allows the car to roll more and react slower reducing responsiveness in and out of the turns. On low bite outdoor tracks with
rubber tires a high roll center will yield the best results. There is a .110” of pin height difference between high and low roll center positions.
Diff Height:
Caution! When adjusting the differential heights, rotate the eccentrics as to loosen the belts, rotating the belts in the
opposite direction, with the belts installed can severely damage the belts.
Diff heights in the
Type R
are also adjustable by rotating the
eccentrics that position them. The diffs can be adjusted from a full low position to a full high position. The low position will allow the car to
roll more and keep the car in the turn longer, increasing on-power steering. The high position will give the car a fl atter and more responsive
feel. It is also possible to change the balance of the car quite drastically by offsetting the heights of the diffs from front to rear. On asphalt
tracks with rubber tires, testing has shown the best results with the rear diff in the low position and the front diff in the high position. On
carpet with foam tires running the diffs in the low position has yielded the best results.
Belt Tension:
The eccentrics have infi nite adjustment positions. Testing has shown that the best setting for the belt tension is to have 3-4mm
of vertical play. Simply move the belt up and down with your fi ngers and tighten down the bulkhead screws to get the desired settings. Gener-
ally a tighter belt tension will give more torque and less top end. A looser belt tension will have less torque and more top end.
Ride Height:
This is the height of the chassis in relation to the surface of the track. A higher ride height may be used on bumpy or slick
surfaces, improving overall handling by generating more weight transfer and chassis roll. A lower ride height will make the car change direc-
tion quicker and should be helpful on high-bite surfaces such as carpet. Testing has show that offsetting the ride height, front to rear (running
the rear ride height 1/2mm higher than the front) will increase steering into the turn. Generally for carpet racing on foam tires a desired ride
height is 4mm. On asphalt or carpet with rubber tires the ride height is kept between 4.5 to 5mm. Please check with your local track for their
minimum ride height requirements.
Over/Under-Drive:
The
Type R
is capable of utilizing overdrive (make the front tires turn faster than the rear) or under-drive (make the front
tires turn slower than the rear). Using a 41T pulley in the front of the car will give it overdrive. This will give the car more steering. Using the
41T pulley in the back of the car will give it under-drive. We have found this to be useful when less steering is needed. Under-drive will also
help the car accelerate through bumps better. It is also possible to run a 41T pulley in the front and back, but it is not recommended.
*Note:
If the pulleys become mixed up, they can be distinguished by a ridge, located in the fl ange on the 42T pulley. The 41T pulley does not have
any type of marking on the fl ange area.
Hex Widths:
The
Type R
comes equipped with plastic narrow hexes (.165”). With Team Losi Aluminum Clamping Hexes it is possible
to widen the car in .030” increments. The rear of the car is maxed out at 190mm, however the front can be widened with different hexes.
LOSA9686 (.195”) and LOSA9687 (.225”) and the stock size is LOSA9685 (.165”). Using the wider hexes can be advantageous with differ-
ent wheel offsets from various wheel manufacturers.
Weight Placement:
Due to the symmetric chassis layout and centered weight design of the
Type R,
weight placement has become an impor-
tant tuning feature instead of just being used for equal balance as with other chassis models. By running the weight bias towards the front, the
car the initial steering will be smoothed out and the car will have less overall steering. By running the weight bias towards the rear, the car
will gain more responsiveness and more overall steering. For stock racing it is important to keep the weight bias 52% in the front and 48%
in the rear which will give the car a smoother feel with the drag brake effects of stock motors. In modifi ed racing the weight bias should be
50% front and 50% rear. If more steering is needed, try moving the weight further back and vice versa. Weight bias can be easily adjusted
by moving your receiver and speed control forward or back. The
Type R
also has balancing holes located in the chassis, there are one at each
end and one on each side. These small holes can be used with balancing pin blocks or simply serve as a reference for supporting your car to
check the weight balance from side to side or front to rear. Note that the holes located on each side are positioned exactly in the middle of the
differential centers, not in the middle of the wheel base (since that is adjustable with arm spacing, caster, and toe-in/out).
Battery Pack:
The unique centered weight design of the
Type R
, along with battery trays to fi t, allows for the use of many different types of
battery packs. For the fi rst time in sedan racing, you can simply replace your standard side-by-side NiMH battery pack with a LiPo battery
pack and the side to side weight balance of your car will remain the same. With other designs it is necessary to add weight to balance the
chassis from left to right, forcing you to increase the weight of the car. This same concept also allows for the use of four and fi ve cell battery
packs as now required by some sanctioning bodies throughout the world. This gives you...a
Type R
owner, the ability to maintain your cars
performance and low weight in any racing category. Please note that with the adjustability of the wheel base, it is still necessary to re-check
your front to rear weight bias when changing battery packs.
seTUP gUIDE
seTUP gUIDE
