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Tamiya DT02 Guide, Mods tuning and tips for club racing review

Overview The Tamiya DT02 series is a very popular range within their line-up of entry level RC cars, in some ways it is the TT02 of the...



Overview

The Tamiya DT02 series is a very popular range within their line-up of entry level RC cars, in some ways it is the TT02 of the off road world. It is strong, cheap and can help you learn the ropes of basic club racing whilst still providing a fun to drive, all purpose buggy.

Different specification DT02 buggies 

There are a fair few Tamiya cars available that use the DT02 chassis. From the range there are several 'specification levels' some with  to higher spec cars with bearings, metal driveshafts, oil shocks, and adjustable top arms. There used to be a DT02MS kit with a lot of hop-ups but that is not available anymore.

Here is a general list of the kits and the basic types of specification they come with:

Base Spec : Plastic drive shafts, Plastic Drive Cups, Friction shocks and fixed upper arms (no adjustable camber)
Tamiya 58470 Holiday Buggy 2010 Blue 
Tamiya 84212 Holiday Buggy Red
Tamiya 58500 Sand Rover 2011
Tamiya 58485 Super fighter GR (and variants with different coloured shells)

High Spec : Metal drive shafts, Drive cups, CVA shocks, ball bearings, large wheels and adjustable upper arms.

Truck Spec : Plastic drive shafts, Plastic Drive cups, CVA shocks, ball bearings (Gearbox only, although the rest are supplied as a Bonus item), large wheels and Fixed Top arms

TRF Spec : Universals, Ball diff, turnbuckles, DF03 alloy shocks, Full ball bearings, Motor Heatsink

As you can see above, there are a lot of chassis to choose from, if you are going to buy one with the intention of doing a little bit of club racing then look for some of the 'High Spec models' as they come with most of the things you need, and you will only need to do a few of the things listed here to make your car club spec

Lots of cars, who actually races them?

The DT02 chassis cars are very popular worldwide, and they are used in the Tamiya Fighter cup series, its very popular in many countries, unfortunately there are no official Tamiya Races in the UK so this series is not ran here.

So when the Farnborough  based buggy club SHRCCC decided to host 'The Tamiya DT02 challenge' it sparked a lot of interest on the Tamiya fan based forums. I fancied experiencing racing in a class where everyone had the same chassis, and where personal tuning and modifications were allowed so I entered the Mod class.

The following describes how I took this entry level car to a competent club racer. There are a range of tips and guides that you can follow to modify your car.

Making 'The RC Racer' Race spec DT02'

For this article I am converting a Tamiya Super Fighter GR, which as listed above is a  'Base Spec' DT02

I looked at the chassis and found several areas that could improve the car based on the Mod class rules. These areas were:
  • Suspension geometry (Camber adjustment, Towers, Arms)
  • Strength (Kingpins, tower brace)
  • Drive Train (Bearings, Diff, universals)
  • Shocks
  • Weight (Shell, screws)
Note : The shims I use are all included in the following Tamiya 53539 Aluminum 5.5mm Spacer Set

I was sure that once I decided to do these, I would have a buggy that I would be proud to race, and it would provide me with enough tuning aids to allow me to make my car work at the track.

NOTE: This guide is very exhaustive, as long as you have a front Suspension brace, bearings and decent oil shocks you will be fine to start racing your DT02 :)

Suspension Geometry

Turnbuckles

Camber adjustment is essential for any real race car. Most DT02 kits come with solid upper arms for the front and rear. Whilst they provide a fixed neutral setting for the new driver, you are not able to tune the amount of lateral grip of the tyres. Tamiya makes the following Hop-up to provide a complete turnbuckle set for your car.

Tamiya 53828 Turnbuckle Suspension Arm and Tie Rod set 
Steel turnbuckles and all the fittings you need to make your DT02 much more adjustable
Turnbuckles are never fun to make, luckily I have a Turnbuckle took and a set of digital calipers so I was able to make them up to the sizes required quickly and easily. Taking the car out for a spin, and adding a little more front camber by shortening the front turnbuckle instantly made an impact on the cars steering ability.
  • NOTE If you have any High spec DT02's  you have adjustable rods so do not need to upgrade to Turnbuckles, unless you want to have easier track side adjustment.

Suspension Settings

The DT02 comes with limited suspension adjustments. The ones provided can give some limited tuning, but as we are racing it is ideal to have more adjustments than the stock settings.

Looking at the base level DT02, the lower arms have 2 mounting positions, but the front upper tower only has 1 mounting position and the rear tower has 2.

I was keen to look at alternatives, especially as having more positions on the outer reach would help the car be more planted when going around corners. The geometry for the basic kit ensures that there is quite a lot of roll which can be problematic if you want to carry speed in the corners.

Luckily Tamiya have released parts that solve this issue with the following two hop-ups
  • Tamiya 54431 DT-02 Carbon damper stay (Front)
  • Tamiya 54432 DT-02 Carbon damper stay (Rear)
The carbon stays fit on to the existing towers, and they provide much more positions to mount the upper shocks. Both sets come with 3mm thick carbon extenders and all of the mounting hardware you will require.
Below is the rear tower with the shock tower making the tops further out, and also providing 4 positions to mount the top of the shock.

Here is the front tower. The shocks are mounted forward due to the front arm mod (see later) also notice the front shock tower stiffener which is included in the front tower kit.

Lengthening wheelbase

The other thing that I noticed was that when testing the stock version of the car that it would have to scrub a lot of speed to make the car turn in, then once the car has started to corner the rear would be quite light again reducing the speed in which you can get around a corner making the car oversteer, not feeling very stable on long corners.

Whilst over-steer is a characteristic of all RWD cars I was convinced that it could be improved upon.

The wheelbase is quite short on the DT02 compared to most buggies, infact many now are extending the wheelbase more such as the latest B4's. Lengthening the car would give more balance better stability in high speed corners and rough tracks, slightly more rear traction and better jumping.

There is no obvious way to do this with the base kit, so I initially thought I was wasting my time, then I had a little bit of lateral thinking and thought about swapping the front lower arms.

So within a few minutes I had swapped the arms around giving me a 12mm longer wheelbase. The effect of this also means that there is more weight over the rear of the car, ensuring that it will be less keen to over-steer.

The arms are easy to swap, although you will need to move the turnbuckles as in the new position they will hit the shocks.

First up you need to change the turnbuckles to fit on the front of the shock tower, I also used a 3mm shim to ensure the turnbuckle will not hit the shock absorber.
You might need a 20mm screw to ensure that the hex head will fit nicely with the 3MM shim.
Then you need to attach the turnbuckles to the front of the C-Hub.

Swap the front C-Hub ball joint to the front of the C-Hub, I used a 2.5mm shim to move the turnbuckle forward to clear the front shocks.
Now you have a car with an extended wheelbase :)
more stability, better jumps and better on high speed corners
Longer wheelbase, note how the tuenbuckles are at the front of the shock tower to avoid the shocks

STRENGTH

The DT02 is a very strong car, however there are some things you can do to ensure you can hit the jumps hard without any worries

Shock tower brace

The front shock tower takes the majority of the knocks, and is the main part that can break on a DT02 chassis. To strengthen it you can buy one of the many third party parts, such as this Carson brace sold at Fusion Hobbies.

Also the 'Tamiya 54431 DT-02 Carbon damper stay (Front)' hop-up comes with a tie-rod that you can fit to make a brace.

If you dont have this hop-up you can easily make your own, you can just make one with some 5mm adjusters, 5mm ball connectors and a piece of threaded 3mm rod (A long screw, turnbuckle etc).
Strong and adjustable

This simple addition to the front shock tower will really help strengthen the tower, and ensure that it is resilient to most crashes.

Suspension shafts

The DT02 has a lot of screw pins that hold the arms and knuckles in place. In the heat of a race they can become loose, and potentially fall out. So to stop this happening I decided to replace them with suspension shafts.

Tamiya doesnt make a set to replace all of the screw pins, so after a bit of research I found the most cost effective way. So to do this you will need the following (Along with some shims)
These are needed for the front end.
First up I used the 3x22mm shafts in the front. You need to replace the front screw pin in the lower arm that fits into the C-Hub.
The lower Suspension shaft is now fitted, do this to both lower arms
Next up, I thought I would replace the screw pin that is used as the king-pin for the steering knuckle. You just need to use the remaining 3x22mm suspension shaft, and 2 separate 1mm shims
Smoother steering and also very reliable
This is a nice easy job, just make sure you use a nice set of long nose pliers to ensure you can fit the E-Clip easily and it doesn't ping across the room when you try to fit it.

The final result, the shims are not essential but it keeps the shaft central.
Now its time to replace the other screw pins with the shafts you have in the TL01 Stainless Steel Suspension Shaft Set.
This set will allow you to replace the remaining screw pins but you will need some shims for the best results
Just take out a screw pin and then replace it with a shaft. These shafts are not the exact match for the screw pins you are replacing but they are close enough, and they will all fit. The pack basically has 2 lengths, you will use the longer ones to replace the inner arm screw pins and the shorter one for the lower rear outer screw pin.

Front inner screw pin

Nice and easy. Take the long shaft and replace the screw pin. You do not need to shim the shaft end as it fits perfectly and there is no binding. Then do the same for the other side.
No shimming needed, and no worries about the arm coming loose.

Rear inner screw pin

You will need another long shaft, To fit this you will need to take of the rear gearbox section from the chassis. Remove the screw pin and then replace it with the suspension shaft. Again this shaft doesn't need any shimming.
A perfect fit, and the rear arms are now fixed solid on the car and will be really free/.

However you will need to file a little bit at the rear of the chassis to ensure that the suspension shaft doesn't rub against the main chassis tub.
Remove a small amount of plastic with a file or Dremel to ensure the shaft is free to move
As can be seen above, you just need to file a small amount of the rear tub on the left and right hand side where the shaft touches the chassis. Just take a little off and then place the gearbox back on the chassis (not screwed) and check the arm falls under its own weight. If it doesn't just file a little bit more and repeat until it falls.

Lower Rear outer.

For this just use one of the shorter shafts (3x35mm) its an easy job to replace them, I found that it was best to add a 1mm shim at one end and a 2mm shim at the opposite end to stop the shaft having any chance of rubbing the inner inside of the wheel.
Add these shims, else the shaft could rub on the inner inside of the wheel.
Now we have a car that has not only more reliability, but also has less resistance in the suspension arms, which will ensure the buggy will react even better to uneven surfaces.

Drive Train

Now we have a car that is strong and adjustable we want to ensure that it is able to deal with some brushless power. The DT02 does not have a lot of gearing options with only the choice of 17t or 19t pinions. It also doesn't have a slipper clutch. A slipper clutch is useful to protect a gearbox from stripping gears, however the DT02 gears are very substantial and in all my years I have not head anyone note that they have stripped any despite seeing some DT02 cars been very thrashed. However there are some things that can be addressed to make the buggy be better on the race track, and also run faster and smoother

Bearings

Just buy a set of bearings, they are cheap and are the most essential thing you can add to any car that has bushings. Your car will be faster, smoother and the drive train will have much less rolling resistance. The DT02 requires the following amount of bearings
They are a straight swap with the bushings in the kit.

As this is a race spec kit, I used their RCB bearings. These are an excellent price option for racers, they are Abec 5 rated, so faster and smoother than std bearing sets whilst not as costly as the ceramic bearings that are also available. Just Search for RCB on the RC Bearings site here

Universals

You will get a much more efficient range of power delivery with a pair of universals in the rear. There are many different manufacturers versions available. The Tamiya ones are
Although any universal's that are for the DF02 or DT02 will also fit.
Better power delivery through the full range of suspension movement
If you have one of the following versions of a DT02 Holiday buggy, Sand Rover, Fighter buggy GX, you will also need a set of these as the plastic diff cups are too big.
These are a straight replacement for the large Cup joints, and once you have this sorted you will be able to use the universal drive shafts.

Differential

The Diff that comes with the DT02 cars is a std bevel gear diff. These are tough units and require no maintenance. The only issue is that it is very loose and if one of the rear wheels comes of the track it can diff out (Where the wheel of the surface will spin up and the wheel on the track will loose drive).

You can replace this diff with the following


However, I have a solution that is much cheaper, and also keeps the bullet-proof bevel gears.

You will need some thick diff oil (I used 500,000 cps oil).
I filled the diff to just under 50% and then put in the internal spider gears
I opened up the diff and put a small amount of the diff grease on the spider bevels so the diff was about half full. These diffs are not sealed but a little amount of AE Green slime and the fact that the oil is like a sticky glue will ensure you wont have any issues (I have checked the diff after a lot of running and have not had any leaks yet).
Nearly ready, just add screws
With the diff half full it is quite stiff, allowing you to put the power down, and keep it down even if a wheel lifts of the ground. You can make it stiffer or looser by just adding more or less oil.  I preferred the feel of the diff when it was just under half full of the oil.

Shocks

The shocks in the base spec kits are simple friction shocks. These will never cut it on a race track, the Tamiya CVA's that come with the higher spec kits are fine, and you dont have to upgrade them.

If you want to go the whole hog you can buy threaded shocks for more fine adjustments. There are a wide selection of shocks on the market, I was lucky to get a good deal on a set of the following
  • Tamiya 54028 TRF Buggy Aeration Oil Filled Damper Set
An assortment of springs is also useful, however the silver springs that come with the friction shocks are pretty good as a base level spring set-up.

Weight

Not much to do here, other than replace the shell for a Lexan shell. I replaced my Super Fighter ABS shell and wing with a Sandviper lexan body set. This saved me over 200g! Lexan shells are also very tough, and less likely to shatter on impact.

Looking fast standing still!

The Decals were made by Mac's Race Team and Grafix, and the shell was painted in my racing colours by my buddy Ian.
The end result was superb, and I have to admit the car is looking very much like a race car now :)

The only other way to reduce weight is to replace the screws with titanium screws, however this is very expensive and I personally would rather just get a steel hex head set as it will be strong.

Lets Race

So with the car eventually ready it was time to race. The track was astro-turf and the weather was sunny so it was going to be a good test for the car.

I was rusty as I haven't driven buggies for a long time, but the car was instantly very planted driving around the track.

The suspension was soaking up the bumps and the car was steering well. I stiffened the front up a little and added a little more camber and the car really started to bite into the corner.

The longer wheelbase also ensured that I was able to keep the power on early in the corner.
Longer wheelbase, more corner speed
The car was soaking up the bumps and I was feeling confident with the way the car handled. The diff was also ensuring that the car was able to put the 10.5 boosted brushless power down on the track. The free drive-train ensured that the motor didn't get hot even though I was being worked hard.

In the end, the only thing holding me back was a few driver errors. The mods that were made to the car did make people notice, the corner speed of the car was really something else, and the car was able to take the rest of the track in its stride.

The buzz of driving this car has really pushed me to race again, so next up is my local buggy track to see how it performs against other manufacturer's cars.

If you have any questions or comments then please post them here or on our Facebook page.

Thanks to John Weston from Iconic RC for the race photos.

Tips 6881192697730595285

Post a Comment

  1. This is an awesome write up! i can't wait to recieve my kid's kits at christmas and modify them!

    I have to ask, why change the suspension geometry with the tamiya pieces? Doesn't moving the shocks outward make the suspension too hard and agressive?

    ReplyDelete
    Replies
    1. Glad you like the write-up.

      Yes you are right the Tamiya towers make the suspension more responsive. It makes the car feel more like a racing chassis than the default set-up, which is still good but a little soft, and not as quick in left to right transitions.

      Delete
  2. Quality stuff! Lengthening the wheel base is soooo cool and something I am doing to my Gator. Will also do the carbon shock mounts. Have the front already, just need the rear.

    ReplyDelete
  3. Cool, looking forward to seeing your finished car

    ReplyDelete
  4. Great write up Craig - car looks great as well ! - Ian

    ReplyDelete
  5. i have a question since iam newbie to this hobby. Which pinion gear should i use if i want get more speed for my sand viper? 17T or 19T? I dont really understand about gear ratio since it has something to do with math.

    Thx

    ReplyDelete
    Replies
    1. If you want more speed then a bigger pinion always makes you go faster. It will take away some of the acceleration.

      Smaller (quicker acceleration, less speed)
      Larger (slower acceleration, more speed)

      Hope that help

      Delete
    2. i have a question about gear ratio but its not for DT02. For example if a spurgear has 74T and the pinion has 21T the ratio is 8,59. Where does this number come from?

      I'll really appreciate your answers

      Delete
    3. The ratio is your spur/pinion. But the final drive ratio is the spur / pinion * internal ratio.

      The internal ratio is the ratio of the main drive gears (I.e on a belt drive TC car it is the diff pully size / lay shaft pulley)

      So for the above the gear ratio is 74/21 which = 3.524 (rounded up)

      This is then multiplied by the internal ratio which is 2.438 (I rounded it up) which will give you the final drive ratio of 8.59

      Thanks

      Delete
    4. how can i find the internal ratio for DT02 and DF01?
      Because i don't really get it about the diff pully size / lay shaft pulley.
      Sorry if i ask to many question.

      Thanks a lot

      Delete
    5. The internal ratio for the DT02 is 2.87. For the DF01 it is 2.437.

      Hope that helps

      Delete
    6. many thanks Racerman......

      Delete

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