- Tamiya F104v2 -

The new F104 Version II Formula One kit is an evolution in design. It does away with the T-plate rear suspension design in favor of the more modern and standardized PBLR (Pillow Ball Link Rear) suspension. The F104 Version II is available as a "PRO" kit. As the name implies, the "PRO" designation warrants excitement as the kit gives formula One R/C racers a good sampling right out of the box. Of the options available for the new chassis, many of these Hop-Up Options are current items, as they were also available for the F104 Version I. There are new Hop-Up Options that can be purchased separately to further enhance the car's performance.

Included Hop-Up Option Overview & Details
While the Pro kit starts off with a great selection of Hop-Up Options, there are a few more options to take the kit to TRF (Tamiya Racing Factory) status! Before we dive into those details, we will take a look at the Hop-Up Options already in the box.

The following Hop-Up Options are included in the kit:
  • 3x35 Aluminum Turnbuckle Shafts (blue) x2
  • 54209 5x5mm Aluminum Hex Head Ball Connector (fluorine coated)

  • Carbon Fiber Chassis Parts
    The included material is made of 3mm thick carbon fiber weave. The bottom plate for the motor pod, the front upper deck, rear upper deck and the body mount plate are also made of carbon fiber. Compared to FRP (Fiberglass Reinforced Plastic), carbon fiber parts offer increased rigidity. Increased rigidity changes the cars handling characteristics. In the case of the F104 Version II Pro, the carbon fiber parts used will improve the effectiveness of the roll and pitch dampers compared to FRP or plastic parts used in their place.

  • 3mm Carbon Fiber Lower Deck
  • 3mm Carbon fiber lower brace
  • 3mm Carbon Fiber body-mount plate
  • 2mm Carbon Fiber Upper Deck (front/rear)

  • Carbon fiber main chassis and upper deck

    Carbon fiber body mount stay and bottom pod

    New Aluminum Diff housing (uses TRF417 diff rings)
    The F104 Version II Pro includes a new, refined aluminum diff housing. The new aluminum diff housing is very similar to the current aluminum diff housing used for the standard F104 chassis. The key difference is the diff rings used are from the Tamiya TRF 417 touring car chassis. The TRF 417 diff rings (item 51417) have 2 notches on the inside of the ring. The notches are needed to make sure the rings do not slip on the aluminum housing. The diff rings from the standard F104 have a hex shape notch on the inside of the ring. These rings have been used in Tamiya F1 cars since the F101 chassis, which was introduced in 1990. The TRF417 diff rings are easier to manufacture and remain flatter compared to the previous diff ring. A flatter diff ring ensures smoother differential action for a longer period of time.

    Pitch and Roll Dampers (54342 RM-01 Aluminum Roll Damper set, 54341 RM-01 Aluminum Pitch Damper set)
    The F104 Version II includes an aluminum pitch and roll damper. They are the exact ones used as Hop-Up Options for the Tamiya RM-01 1/12 chassis.

    The pitch and roll dampers use aluminum fluorine coated shock bodies for smooth piston damper movement. The dampers also have threaded shock bodies for easy adjustment of the spring retainer, in the case of the pitch damper.

    Clamp Type Wheel Hub (54240)
    The aluminum clamp type wheel hub has two points in which the hub is secured to the left side of the rear axle. The clamp style hub also ensures the axle is not stress fractured when using a carbon axle shaft. The standard F104 hub uses only one grub screw to secure the hub.

    F104 Low Friction Suspension Ball Set (54161)
    Fluorine coated hex head ball connectors have less friction compared to steel ball connectors. Less friction in suspension movement ensures your settings operate as free as possible.

    F104 Aluminum Upper Suspension Mount (54202)
    The Hop-Up suspension mount offers two additional camber settings compared to the plastic mount. There are four camber angle setting options available: 1.0, 1.5, 2.0 and 2.5. The stock plastic piece has 0.0 and 1.0 degree respectively.

    Aluminum Horn for Hi-torque servo saver (F104 - 54159)
    The servo savor included with kit is made of ABS plastic. The aluminum Hop-Up Option horn is stronger and will have less flex during steering input than the standard servo horn.

  • 04 Module Spur Gear Set (93T/104T - 53900)
    The 04 module spur gears have been a staple gear set since the F102. These option gears contain molybdenum for reduced friction resistance.

    Low Friction 5mm Adjuster (53601)
    5mm adjusters are used in almost every Tamiya on-road kit. The low friction Hop-Up contains molybdenum for reduced friction resistance compared to the standard plastic and will last up to three times longer.

    Fluorine Coated 5mm Aluminum Ball Connector (53599)
    Fluorine coated ball connectors have less friction compared to steel ball connectors. Less friction in suspension movement ensures your settings operate as free as possible and resist debris.

    Hi-Torque Servo Saver (51000)
    The Tamiya Hi-Torque Servo Saver uses three C-shaped steel springs to absorb the rigors of open wheel racing where a collision of the front wheels may add stress to the internal gears of your steering servo.

    F1 Front Spring Set (50509)
    The F1 front spring set includes soft, medium and hard tension coil springs to fine tune the F104 Version II suspension to track conditions.

    3x35 Aluminum Turnbuckle Shafts (blue)
    Aluminum turnbuckles lower the weight of the car and the anodized blue color matches the other blue accents found throughout the F104 Version II kit.

    Separately available Hop-Up Options
    Now that we covered the Hop-Up Options that are standard features in the F104 V.2 kit, we will take a look at what else is available and what those option parts do.

    54162 RC F104 Carbon Rear Shaft
    The included axle in the F104 Version II Pro is made of steel. The carbon rear shaft is half the weight and offers quicker throttle response compared to the steel axle because it has less rotating mass. Both the steel and carbon axle can be used to fine tune the throttle response according to track conditions.

    54351 RC Carbon Damper Mount Plate
    The stock damper mount plate is made of plastic (PA-GF). The Hop-Up Option is made of 2.5mm thick carbon fiber plate. It replaces the stock C-9 part and improves the effectiveness of the pitch and roll damper.

    54352 RC Roll Spring Set
    The stock roll spring is medium in stiffness. This Hop-Up Option set comes with soft, medium, hard and super hard springs. The four spring choices will allow the user to custom tune their F104 Version II to changing track conditions.

    54356 RC Aluminum Motor Mount
    The aluminum motor mount Hop-Up Option replaces the plastic kit standard C1, C4, C8 and C10 parts. The aluminum motor mount is not only stronger and more rigid, but it dissipates heat generated from the motor which in turn allows it to run cooler.

    54357 RC Adjustable Metal Upright
    The standard steering uprights in the F104 Version II kit are made of metal and carbon nylon plastic material. The Hop-Up Option uprights are made of aluminum and use a steel shaft that can be positioned for either in-line or off-set trailing positions. The in-line position is suitable for slow speed technical track layouts whereas the off-set trailing position is best for high speed circuits. The trailing position also exhibits less responsiveness to steering input, which can be better if you're looking for an easier car to maneuver.

    54160 RC F104 Titanium Coated King Pin
    The titanium coated surface prevents damage and offers increased toughness and smooth operation compared to the standard chrome plated king-pins found in the kit.

    54359 RC RM-01 Pitch Spring Set
    The included kit spring is medium. The Hop-Up Option spring set includes: Super Soft, Soft, Medium, and Hard. The springs can be used to further fine tune the pitch characteristics of the car according to track conditions. Harder springs are typically used on very smooth track conditions, whereas softer springs are used in bumpy track conditions.

    53901 RC TRF Special Damper
    The F104 Version II Pro allows the user to use the included RM-01 pitch damper or the Hop-Up Option TRF special damper. As opposed to the RM-01 pitch damper, the TRF damper has a bigger shock body, which holds more oil volume. The TRF damper also has 3 piston choices compared to the single piston choice of the RM-01 pitch damper. The use of the TRF Special damper gives the user greater flexibility when tuning their car for the track.

    54360 RC RM-01 5mm Short Ball Nut Fluorine Coated Aluminum
    These lightweight, aluminum ball connectors are designed for use with the stock F104 steering uprights. The short ball nut features a fluorine coating to ensure smooth steering operation. They have a lower height than the kit-standard parts and settings may be adjusted through the use of spacers, which are available separately.

    54375 RC Carbon Rear Bulkhead Plate
    The 2mm carbon fiber plate Hop-Up Option replaces the kit-standard C8 part. It links the left and right plastic or aluminum motor mounts together for greater rigidity.

    54203 RC F104 Alum Servo Mount L/R
    The blue anodized aluminum servo mounts replace the kit standard D13 and D14 plastic pieces. They offer increased rigidity and sharper steering response.

    Initial Building Advice:
    The Tamiya F104 Version II kit is easy to build and there are a few things to consider when buying the items necessary to complete your F1 machine.

  • Radio gear
  • Motor selection
  • Battery choice
  • Servo choice
  • Tire selection

  • Radio Gear:
    Just like full scale Formula One racing, the confines of its Radio Control counterpart is no different in terms of space available to fit the inner workings of the car. It is recommended that one find the smallest receiver and ESC (electronic speed control) as space is very tight, especially if you prefer to run the available Tamiya body sets to their most realistic setting. If you build the Ferrari F60, McLaren MP4-24 or the original F104 Pro body set you have the option of using the highly realistic side pontoons. Therefore, choosing this setting requires the smallest receiver possible with a small ESC to match.

    Motor Selection:
    The cheapest motor to install is the Tamiya 540-J spec Johnson brushed motor. This motor is available separately or it can be found in most Tamiya RC kits. It's a great and inexpensive basic motor to get you up and running. For experienced builders and hobbyists, brushless motors have become the standard technology to race with. The best power to weight solution for the motor wind specification with regards to brushless technology is the 540 21.5. Since Tamiya F1 cars are direct drive (spur gear to pinion), power loss through a transmission is non-existent. With a 21.5 motor and a 4000mah battery, one can run their car for up to 30 minutes on one charge. Most club level racing has adopted this power formula as it keeps the speeds reasonable and makes it fun for all levels of skill.

    Brushless 540 motor

    Tamiya 540-J Johnson brushed motor

    Battery Choice:
    Battery technology has changed over the years. Experienced users are using Lithium Polymer battery technologies commonly referred to as LIPO batteries. LIPO batteries are available in 3 basic sizes: rounded hard case to match the size of a common NiCd or NiMh stick battery pack, LIPO hard case brick shape, which has become a standard among experienced hobbyists and its short sized cousin the "shorty pack", which is a shorter size brick configuration. The brick shaped battery configuration has the same basic footprint as a normal stick pack, but the pack is rectangular in shape. A "shorty" pack is a shortened version of the normal hard case brick pack. The short pack gives experienced builders the ability to shift weight in the car to suit track conditions. In the case of the F104 Version II, it allows the builder to mount the battery forward giving the builder ample room in the rear of the car to mount the ESC and receiver. The short LIPO option is probably the best choice for most advanced users building the F104 Version II.

    From left to right: NiMh 7.2v stick pack, 7.4v Lithium Polymer stick pack, 7.4v brick pack & 7.4v short brick pack

    Servo Choice:
    The F104 is designed to use a standard size servo. The instruction manual provides information on how to mount the servo by cutting the servo's screw mounting tabs off on both ends. This method works well; however, there is a better solution for hobbyists who want to preserve their servos screw mounting tabs for future use. Many manufactures offer servos that are marketed as "low-profile" servos. They are the same basic size looking at them from the servo horn side, but have a much shorter depth. The low-profile servo size allows you to mount the servo so it's flush with the bottom of the chassis. The servo horn is now positioned horizontally rather than vertically as the manual shows. No modification of any kind is needed to mount the low-profile servo in this manner. The only thing one must do is add 4mm of spacing to the steering linkage ball connector attached to the servo horn. Tamiya item 53539 is the perfect spacer set for this application. By mounting a low-profile servo in this fashion you will also eliminate the "bump-steer" inherent to the standard installation method of a standard size servo. "Bump-steer" is something that will affect your roll-steer. Bump-steer is not necessarily a bad thing to have in a car, but if you'd like to remove it from your set up, the low-profile servo method is the best and easiest method in eliminating it.

    Low-Profile servo

    Standard size servo

    The effects of "bump-steer":
    Definition: "bump steer" is the term for the tendency of the wheel of a car to deviate from its static steering alignment during suspension movement. It is typically measured in degrees of steer per meter of upwards motion or degrees per foot. If a car has "bump-steer" you can tell by pushing down on the front of the car while both wheels are pointed straight forward. If both wheels turn to the outside while the suspension is compressed you have "bump-steer". On modern cars the front of the tire moves outwards as the suspension is compressed, a process known as the front wheels "toeing out". This gives roll under-steer while cornering. The F104 servo location and mounting method was designed to allow the car to under-steer slightly, thus making the car easier to drive for new hobbyists to the sport. For advanced racers, eliminating "bump-steer" can offer benefits that help the car steer more aggressively and help it carry more corner speed. Tuning "bump-steer" is one method one can fine-tune the F104 Version II PRO according to track conditions.

    Low-Profile servo installed, servo horn sits Horizontally.

    Standard size servo position, servo horn sits Vertically.

    Horizontally mounted servo horn causes steering links to sit at 35 degree angle, which causes "bump-steer" as the wheels compress during suspension travel.

    Tire Selection:
    The F104 Version II Pro may use foam or rubber tires. Tamiya makes wheel sets that accommodate each type of tire. Typically, foam tires are best to use on carpet surfaces. They generate a lot of traction and make for some very exciting driving. However, they're not ideal outdoors as they are more prone to wearing out quickly and are susceptible to damage.
    Rubber tires will work best outdoors and work well indoors depending on the compound. The advantage with rubber tires is gear ratio consistency. As foam tires wear they get smaller in diameter, which changes your final drive gearing. You have to make sure to update your gearing as the tire gets smaller and adjust again as you put on fresh size tires.

    Foam and rubber tires

    Basic Tuning Advice
    Roll Damper Spring Selection:
    Roll springs on the F104 Version II offer different handling characteristics. Typically the softer the spring, the more the car will carry speed through corners, but will be slower to enter the turn initially. The harder the spring the more aggressive the car will turn and will also feel more aggressive in terms of steering feel. The trade-off is loss of corner speed. The appropriate spring should be used depending on track conditions and your comfort level with chassis responsiveness. If the track layout has high speed 180 tight turns, the harder roll springs are desirable. If the track has many sweeping long turns, then the softer spring is a better choice.

    How to Set the Tension with the Roll Springs:
    The side roll springs control chassis tweak as well as roll. When you first install the springs, they should not have any compression or pre-load. Back the 3mm set screw to the point where the spring barely touches the rear carbon motor plate. To make sure the main chassis and motor pod are not tweaked, hold the car upside down and compress the left and right side a few times so the pod takes a proper set. Now that the pod has taken its proper set, check for tweak. Make sure the car has the motor installed when checking the tweak of your car. The outer left and right points of the motor pod will line up perfectly to the main chassis for proper tweak. If these points are not lined up level to the main chassis, then the main chassis will be biased to the left or right which will result in your car possibly not turning the same way left to right. To make corrections, simply tighten or loosen the side that needs adjustment. If the right side of the motor pod sits lower to the main chassis, tighten the left side screw slightly and check tweak again. Make sure to compress the left and right sides a few times before determining if adjustment is needed.

    Initial setting for roll spring with no pre-load.

    Main chassis and bottom motor pod not lined up.

    Properly tweaked main chassis and bottom motor pod. Adjust roll springs to obtain alignment.

    Roll Damper Oil Selection:
    Use lighter weight damper oil for low-grip surfaces. Use heavier damper oil for high-grip surfaces. The oil you select will also affect steering responsiveness. Generally, heavier damper oil will result in a sluggish responding car and vice versa.

    How to set your droop:
    Droop is the amount of chassis sag when the car is lifted from the front or the rear. In order to understand how this affects your car we will first go over some definitions explained below to better help you understand the basic tuning advice: Pod Droop is how far the bottom motor pod plate drops below the chassis' horizontal plane at the center shock's full extension. Basically, if you look at the car from the side, and hold it in the air it's how many millimeters the bottom plate angles downward. If your car does not have pod droop a straight edge ruler run across the bottom of the main chassis and the bottom pod will lie perfectly flat on both planes. If you see a gap in the form of a "V" pointing downward, then you know your car has pod droop. The easiest way to calculate a measurement in millimeters is to put the car on chassis blocks. Most chassis blocks come in 10mm size. Using a ride height gauge measure the distance of your flat surface to the leading edge of the F104 V.2 bottom motor plate. Subtract the result from your 10mm chassis blocks and the result will be your pod droop in millimeters. If the leading edge of your bottom motor plate measures 10mm, then you have 0 mm of pod droop. If the distance measured is 9, then you have 1mm of pod droop. Knowing this number will help you keep detailed logs of your cars setting, which will help you return to settings that you know work for different tracks you may race on. Racers will add "pod droop" if tracks conditions are bumpy.

    Pod droop. Pod sits below the horizontal plane of the main chassis. Usually set for bumpy tracks.

    Rear Chassis Sag is the amount of distance your car will "sink" before the suspension takes its final set. The best time to determine a value is when the car is completely ready to run and ready to be put on the track for running. Push down on your car. The car should squat and return up, but not all the way unless you have your center shock spring set with a lot of pre-load. If you gently pull up on your car from the center, the chassis should lift until it hits the shock's full extension. It's usually about 1/2 mm, but sometimes more (especially if you have a lot of Pod Droop (bumpy track typical setting). The more Chassis Sag you have, the mellower your car is to drive, but if you have a lot of Sag, and a lot of Droop, the car will be very unpredictable. You will notice the unpredictability especially in "off-power" as in when you let off the throttle to enter a sharp 180 degree turn. The unpredictability occurs because the droop will let too much weight transfer to the front of the car. The best way to get the ideal droop setting is to tune the rear shock length so your F1 car does not swap ends (loose rear traction) when letting off throttle abruptly. If the surface your racing on has a lot of traction and your car under steers severely when entering a turn, then add more droop to the rear of the car to transfer more weight to the front when "off-power". The weight transfer to the front will help your car steer more sharply. It's a fine balance and easily over looked if you have off-power traction issues.

    Front end Droop is the amount of distance your car will "sink" before the suspension takes its final set. The front end of the Tamiya F104 Version II incorporates a very simple coil spring and king pin design. The kit comes with a silver (soft), gold (medium) and black (hard) selection of coil springs. Your choice in spring selection will be greatly influenced by the track conditions. If the track is bumpy a soft spring is desirable. If the track has high traction and is smooth, the harder spring will be best to use. Keep in mind, the front spring selection will also influence weight transfer to the back of the car.

    The front end droop is easily adjusted by the two screws found on the lower part of the front suspension. The directions in the kit do not explain the screws purpose, but it is there to adjust front end droop. The more spacers you add to the bottom of the screw head the less front end droop you will have. The screws limit the top of the front suspension control arm. The taller you make the screw the sooner the top control arm will bottom out resulting in less droop.

    The screw on the lower suspension arm controls droop. Less spacers increases droop value.

    The easiest way to measure your front end droop is to measure your front ride height (use millimeters as your method of measure). Make sure the car is fully equipped as if it's ready to hit the track. Then lift the front end and measure the front ride height again once you see the front tires barely lift from your flat set up board or table. The difference between the two measurements will give you the droop value.

    Measure the front ride height with a full race ready car.

    Measure again once the front wheels barley lift off.

    Always measure the front ride height at the very front part of the main chassis.

    The range you should play with is between 1mm-2mm. A 2mm setting will make the car very easy to drive on power as more weight is shifted toward the rear, resulting in more rear traction, but it will have a tendency to have less steering on power. If conditions warrant more on power steering exiting a corner, then consider reducing the droop to 1mm (less weight is transferred to the rear resulting in more on power steering). Use caution when taking out droop as you may go too far and end up with a car that is unbalanced.

    The rear end droop value can also be measured in the same method mentioned above. Measure the rear ride height of the main chassis (not the rear pod) and lift the rear of the car and measure again once the rear wheels lift slightly. The rear droop value should never exceed 1mm for your base setting unless you encounter extreme traction conditions where the car understeers like a truck. Keep in mind you will have a very unbalanced car if your front and rear droop values are extremely different. The baseline variance should never exceed 2mm between the front and rear droop value, otherwise your car will behave very erratically in one extreme.

    Measure the rear ride height with a fully race ready car.

    Measure again once the rear wheels barley lift.

    Always measure from the furthest point of the main chassis.

    Pitch damper setting:
    The pitch damper is the main damper in the rear of the car that controls how the rear end of the car will react to a bumpy or smooth track surface. Use softer oils and springs for bumpy tracks and use harder oils and springs for high traction smooth tracks.

    Front tire toe-angle adjustment:
    The toe angle of the front of the F104 Version II can be adjusted so the front tires toe-in or toe-out. Since the F104 V.2 is a rear wheel drive car you will have more stability if you put toe-out in the front end. Toe-out means both your front wheels will point outward when looking at your car from the top. Toe-in means your wheels will point inward when looking at your car from above. Toe-in will result in a car that handles erratically and is very sensitive to steering input. One to two degrees of toe-out is a good starting point for most conditions and it will be easier for the driver to handle.

    Closing comments:
    The F104 Version II Pro is a racing chassis that's easy to build with a plethora of tuning options. Even though the car is simple compared to a full fledge independent suspension touring car, the adjustments possible are profound and can make all the difference on the track in order to maximize its handling and speed. It takes the proven front end design of the F104 "version one" and adds the modern rear end design of the RM-01 platform to bring Tamiya racers the best Formula One racing chassis to date in the Tamiya product line. It has also been carefully designed and laid out to accommodate Tamiya's most realistic and scale licensed modern era Formula One body sets to date.