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Differential Adjustment: Never allow the diff to slip; that's what the slipper is for. Before trying to adjust your diff, you need to tighten the
slipper until the spring is fully compressed. Next, hold the spur gear and right rear tire, then try turning the left rear tire forward. It should be
very diffi cult to turn the left rear tire. If the tire turns easily, the diff is too loose. To tighten the diff, line up the slot in the diff screw with the
groove in the left out drive. Place the 1/16" Allen wrench through both of these slots. This will lock the diff screw and the out drive together.
While holding the Allen wrench in place, turn the right rear tire forward about 1/8 of a turn. Check the differential adjustment again and
repeat the tightening process as necessary until the differential is no longer slipping. See "Slipper Adjustment" below, and then continue from
here. The fi nal differential adjustment check should be made by placing the car on carpet, grass, or asphalt and "punching" (quickly applying)
the throttle. The differential should not slip. If it does, tighten the diff in 1/8-turn increments as described above until the slippage stops.
Once the diff has been adjusted, it should still operate freely and feel smooth. If the diff screw starts to get tight before the diff is close to
being adjusted properly (based on slip), the diff should be disassembled and inspected; you may have a problem with the differential assem-
bly. Refer to the assembly instructions to ensure that the diff is properly assembled and that all parts are properly seated in the assembly.
Motor Gearing: The important thing is to keep the motor in its optimal RPM range as much as possible around the entire track. This will
depend on the straight-away length and the size of the infi eld turns. The chart below is a guide to give you a starting point. You may want
to try gearing up (larger pinion or smaller spur) or down (smaller pinion or larger spur), one size at a time, noting the straight-away speed
and acceleration through the infi eld.
*NOTE: OVER GEARING (TOO LARGE OF A PINION OR TOO SMALL OF A SPUR) CAN CAUSE DAMAGE TO BOTH YOUR
ELECTRONICS AND MOTOR. USE CAUTION WHEN SELECTING YOUR GEARING.
Gear Ratio Calculation: The XXX-CR includes a 78-tooth, 48-pitch Kevlar® spur gear. The overall internal drive ratio of the transmission
is 2.43:1. The pinion gear that is used will determine the fi nal drive ratio. To calculate the fi nal drive ratio, fi rst divide the spur gear size by
the pinion gear size. For example, if you are using a 21-tooth pinion gear, you would divide 78 (spur gear size) by 21 (pinion gear size);
78/21=3.71. This tells you that 3.71 is the external drive ratio of the transmission. Next, multiply the internal drive ratio (2.43) by the external
drive ratio (in this case 3.71). 2.43x3.71=9.02. This means that by using a 21-tooth pinion gear with a 78-tooth spur gear, the fi nal drive ratio
is 9.02:1. Consult your high-performance shop for recommendations to suit your racing style and class. The chart below lists some of the
more common motor types and a recommended initial gearing for that motor. Ratios can be adjusted depend on various track layouts, tire
sizes, and battery types.
Shock Location: The XXX-CR has four mounting locations on the front shock tower. The position can be easily adjusted by simply mov-
ing the top of the shock to another hole. The standard location (third hole out in the tower) works best on most tracks. Moving the top of the
shock out one hole will result in an increase in steering and the car will react quicker. Moving the top of the shock inward a hole will slow
steering response time and make the car smoother in bumps. The standard position on the arm is middle which offers the best balance from
track to track. When using the inside shock position you will want to move the shock in on the tower to keep the angle same angle as the
stock location. A stiffer spring will be needed when using the inside shock location to obtain the same roll stiffness. Running the inside shock
location will give the car more steering into the turn and less steering on corner exit. Running the shock location outside on the front arm
will give you less overall steering into the turn and keep the front end fl atter through the turn making the car smoother and easier to drive.
This can be used on high bite tracks. Keep in mind as you move the shocks in on the arm will require internal limiters to obtain the correct
suspension travel. For the inside location a .090" limiter works great. Team Losi sells a shock spacer set (LOSA5050) that includes .030",
.060", .090, and .120" spacers.
Static Camber: This refers to the angle of the wheels/tires relative to the track surface (viewed from either the front or back). Negative
camber means that the top of the tire leans in toward the chassis. Positive camber means the top of the tire leans out, away from the chassis.
Camber can be precisely measured with after market camber gauges, sold at a local hobby shop. It can be measured (roughly) using any
SETUP GUIDE
SETUP GUIDE
Tuning the Transmission of the XXX-CR
Motor Manufacturer, Make/Model
EPIC Based Monster
EPIC Based Binary (Two Magnet)
EPIC Based Binary (Four Magnet)
EPIC Based P2K/P2K2
TOP Based (Standard Brush)
TOP Based (V2)
Yokomo Based
All 19 Turn
10 Turn
11 Turn
12 Turn
13 Turn
14 Turn
15 Turn
Table 3: Suggested gearing.
Tuning the Front End of the XXX-CR
Spur
Pinion
78
23
78
23
78
22
78
23
78
21-22
78
21-22
78
21-22
78
23-24
78
20
78
20
78
21
78
22
78
23
78
24
20
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