BMI Racing DB12RR User Manual

Message from BMI Racing

The DB12R is a revolutionary step forward in 1/12th scale car design. Two years of research and
development has culminated in the kit you have before you. The goal of the DB12R project was to take the
best features of T-bar cars and Link cars and combine them to make a new type of rear suspension that will
set new standards for speed, versatility and ease of use. I call this new suspension system the BMI Flex Link.

What if you could have a t-plate car that was as stiff side to side as with a .075” t-plate but more flexible front to
rear than a .063” t-plate with 2 screws in the read pod?

What if you could have a link car that had insane steering with very little front wheel travel, transitions left to
right in chicanes like it was hard wired to your brain and was equally at home on carpet and asphalt?

Stop wondering, the DB12R delivers on all of the above.

The DB12R’s suspension allows racers to enjoy the rising side to side spring rate inherent in a T-bar rear
suspension system with the separation of the front to back versus side to side spring and damping effects as
seen in link cars. This allows serious racers to balance forward traction, side traction and steering
aggressiveness independently of each other with the ultimate goal in mind. This means FASTER LAP TIMES!

Please read through the instruction manual carefully. Even if you are an experienced R/C racer, there are
some details about the DB12R that are different. To get the most out of your kit you must have it assembled
correctly.

With Regards,

Items needed to assemble your DB12R

1. .050”, 1/16” and 3/32” Allen wrenches

2. A #2 Phillips Screwdriver

3. 3/16” and 11/32” nut drivers

4. A pair of needle nose pliers

5. A pair of slip join pliers

6. A hobby knife

7. A ruler or calipers

8. A file

9. A soldering iron

10. Diff Grease

11. Electric Motor Cleaner Spray

12. 35wt silicon shock oil (for center shock)

13. 5000wt silicon diff oil (for damper tubes)

Jason Breiner

BMI Racing

Items needed to operate your DB12R

1. Two channel surface Radio system

2. A mini servo*

3. One or more 4 cell battery packs

4. A battery charger

5. An electronic speed control

6. An electric motor

7. A 64 pitch pinion gear

8. A small servo saver.

9. 1/12thscale body

10. 1/12thscale tires

* The DB12R was designed for servos with
dimensions similar to the Futaba 9602 and 9650.
These will fit perfectly with a centered output shaft.
Other servos will fit but may require different servo
mounts and/or modifications to the lower chassis.

Front suspension assembly

Step 1

Locate your lower front suspension arms and the
hard anodized alloy pivot balls. Note that the arms
are symmetrical. At this time you must pick which
one will become the left and right arms as this will
determine how you pop the pivot ball into the arms.

Pop the pivot balls into the arms with the shoulder
on the ball facing up. Do this by placing the ball on
a hard flat surface and placing the arm over the
ball. Carefully push the arm down over the pivot
ball. Be careful. It will take a lot of force.

Special Note:
The DB12R uses IRS hard anodized alloy pivot
balls and the new IRS lower suspension arms. If
the balls are tight in the lower arms carefully
squeeze them with pliers until the ball just begins to
move freely

Step 2

Locate your upper suspension arm rod ends. Note
that the top side of the rod end opening is smaller
than the bottom

With a hobby knife, carefully chamfer the top of
the rod ends opening. This creates clearance for
the king pin shims that will go here later. This will
ensure there is no binding in the suspension.

The inset picture shows a finished rod end.

Step 3

Locate the two remaining hard anodized alloy pivot
balls and snap them into the upper arm rod ends with
the shoulder on the ball facing down. As with the lower
arms, squeeze the rod ends if the balls do not move
freely.

Step 4

Locate the upper suspension arms, the upper arm
turnbuckles and assemble as shown above.

We prefer to thread the right hand thread portions
of the turnbuckles into the rod ends and the left
hand thread into the upper arms.

Note:
The arms have a bottom and a top. They have
small circular impressions on the bottoms.

Step 5

Locate the 10 degree reactive caster upper
suspension mounts, upper suspension hinge pin,
e-clip and nylon caster spacers.

Assemble as shown.

Make sure the upper suspension arms pivots
freely. If there is any binding at all, the car may
handle poorly. If the upper arms are tight, use the
back of a hobby knife to scrape the front and back
of the reactive caster blocks and the inside of the
upper suspension arms to make more clearance
for the caster spacers. Take your time here and
get it right!

Special Note:
The DB12R uses IRS upper hinge pins and does
not require setscrews in the upper suspension arm
mounts.