ORC Amemiya SGC-7

I had been thinking for a few months about a "high end" chassis that would be suitable to run on the quite dirty track where I often gather with my friends. The "open air" gearings on my TA-04 TRF being strictly incompatible with such a dirty track, my TL-01 practice chassis was the only candidate left since I sold my TT-01 chassis. Of course, the pleasure to drive is not the same as with a "quality" chassis.


The TB-03 family

As past experience shows, the TB chassis family never was outrageously model prolific. Again, this third generation is made of only 5 models plus an hopped-up R version in limited series:


58409 ARTA Garaiya

Tamiya 58409 ARTA Garaiya

58412 Xanavi Nismo GT-R (R35)

Tamiya 58412 Xanavi Nismo GT-R (R35)

58424 Takata Dome NSX 2008

Tamiya 58424 Takata Dome NSX 2008

58425 ORC Amemiya SGC-7

Tamiya 58425 ORC Amemiya SGC-7

58434 Calsonic IMPUL GT-R 2008

Tamiya 58434 Calsonic IMPUL GT-R 2008

84109 TB-03R

Tamiya 84109 TB-03R

Photos © Tamiya 


It looks like the series has already ended since the last kit was released back in 2009. Surprisingly, all the bodyshells come from the Japanese Super GT Series Championship: Tamiya usually offers a much wider range of body types in order to please more fans outside Japan. This might explain why the TB-03 chassis doesn't seem to sell very well on this side of the planet. Except for the GT-Rs, you can notice the bodyshell designs are quite complex.

In addition, there are two more versions dedicated to drift usage, one being the standard chassis and the other being a fully hopped-up limited version with the motor moved up in central front position:


58420 TB-03D Drift Spec Chassis Kit

Tamiya 58420 TB-03D Drift Spec Chassis Kit

84205 TB-03 VDS Drift Spec Chassis Kit

Tamiya 84205 TB-03 VDS Drift Spec Chassis Kit

Photos © Tamiya 


Unlike the classic TB-03 (again: on this side of the planet), the drift versions seem to be very much appreciated by fans. The missing bodyshells from these versions seems to correspond to most "drifters" choice to mostly use very detailed custom bodyshells.


My TB-03 chassis when it arrived

With very good advice from Garrison on Vintage-RC, I incidentally spoke about the TB-03 chassis with my friend CactusZeBest. A few days later, the postman was delivering his chassis he wanted to sell laughing.


View from above

Tamiya 58425 ORC Amemiya SGC-7 - TB-03 as arrived

The under chassis

Tamiya 58425 ORC Amemiya SGC-7 - TB-03 as arrived


No wheels, no bodyshell, but very interesting upgrades. About the chassis condition, a few scratches show it was run, but there is no sign of crash: the chassis is in very good condition.


Upgrades already installed

Several upgrades are recommended to make a TB-03 more reliable whenever you want to install a powerful motor. The chassis I received already have some of them:


54056 Alum Diff Joint Set

Tamiya 54056 Alum Diff Joint Set

53571 TRF Dampers Fluorine Coated

Tamiya 53571 TRF Dampers Fluorine Coated

54091 Aluminum Servo Stay (L)

Tamiya 54091 Aluminum Servo Stay (L)

54096 Aluminum Servo Stay (R)

Tamiya 54096 Aluminum Servo Stay (R)

TB03-01 Universal Shaft

3Racing TB03-01 Universal Shaft

TB03-10 Graphite Main Shaft

3Racing TB03-10 Graphite Main Shaft

TB03-12 7075 Propeller Joint

3Racing TB03-12 7075 Propeller Joint

TB03-13 7075 Bevel Gear Shaft

3Racing TB03-13 7075 Bevel Gear Shaft


Let's start from the beginning:

  • Alum Diff Joint Set: replacement for the stock plastic parts. Required when using a powerful motor.
  • 53571 TRF Dampers Fluorine Coated: the best dampers from Tamiya. Even better than the stock classic CVAs, but definitely more expensive. These are the same as on my TA-04 TRF.
  • 54091 and 54096 Aluminum Servo Stay: useful to secure the steering servo. Surprisingly, you can't find a set combining the left and right stays (you require both, though).

Last, upgrades from 3Racing:

  • TB03-01 Universal Shaft: front and rear, they reduce play when transmitting power to the wheels.
  • TB03-10 Graphite Main Shaft: lighter than the stock part, it is needed because of the next parts.
  • TB03-12 7075 Propeller Joint and TB03-13 7075 Bevel Gear Shaft: they reinforce the connection between the main shaft and the front and rear gearboxes.

Among these upgrades, only the aluminum differential joint set, the universal shafts and the servo stays are really interesting and the TRF dampers are undoubtedly much better than the stock units. As for the graphite main shaft and subsequent propeller joint and bevel gear shafts, I won't remove them but I think the stock parts would have been good enough.


Additional upgrades

Like I said previously, my goal with this TB-03 is to replicate what I have with my TA-04 TRF: upgrades I am going to install may not serve to make the chassis more reliable. However, I need them to provide my TB-03 a standard of performances that can compare with my TA-04 TRF's.


53842 TA05 Stabilizer Set (F & R)

Tamiya 53842 TA05 Stabilizer Set (F and R)

54151 High Precision Bearing Holder

Tamiya 54151 High Precision Bearing Holder

54054 Aluminum Motor Adapter

Tamiya 54054 Aluminum Motor Adapter

54094 Aluminum Spur Gear Mount

Tamiya 54094 Aluminum Spur Gear Mount

54055 04 Module Spur Gear

Tamiya 54055 04 Module Spur Gear


Anti-roll bars front and rear improve the chassis handling: actually, they are the TA-05's chassis. However, you need to follow instructions found in the TB-03 manual to fit them: instructions supplied with the anti-roll bars are made for the TA-05 and won't suit since the front IFS system requires a specific fitment.

The next parts will all go to the same place on the chassis: close to the motor mount.


Stock parts and their replacement

Tamiya TB-03 stock vs new parts

Final assembly

Tamiya TB-03 New parts


Some explanations:

  • 54151 High Precision Bearing Holder: this part holds a 1050 ball bearing guiding the bevel gear into the rear differential housing. It also acts as a support between the spur gear and the motor mount. The stock part is in plastic (part K5 step 2 in the manual): the upgrade part is in Delrin resin which is more effective and reduces the risk of wear and play that would damage the spur gear.
  • 54094 Aluminum Spur Gear Mount: this part drives the spur gear. It is more solid and stiffer than the stock plastic part: it will better handle powerful motors.
  • 54055 04 Module Spur Gear: useless part for the majority of cases. However, switching the spur gear and the motor pinion to 0.4 pitch will increase the ratio choice and will be less noisy. I installed this part only for my TB-03 chassis to be as close as possible to my TA-04 TRF.
  • 54054 Aluminum Motor Adapter: the stock motor mount is in metal, but not this tiny part that is used to fix the motor placement. It is required to handle powerful motors.