TOPIC:

I still don't really get why they decided to make the T-bar asymmetrical on the F103.
Seems like an unneccessary evolution of years with all the varying diff parts...

Btw - this doesn't work because I spaced the wrong side of the diff so the pinion can't reach the spur :


I discovered that very late in the process...
Other than that, the dimensions are very close to what they should be.
But trying all this out, I think I may have found the solution.
If I am not mistaken, the diff joint of the F103RS is the correct length and will fill the right side of the axle :


But I will most likely still have to make some spacers. With a 6mm hole btw.
This time between the diff parts and the hub I'm guessing...


I'm using the different wheels now because the 'Goodyears' were actually quite worn - by 10mm.
They looked pretty good but might not have given much traction anymore.
Plus the fact that Group C hubs use diff thrust parts that are independent from mounting the wheel...
So when I switch the foams between this car and my Group C chassis, I don't have to adjust the diff tension every time.

I should be able to try out that longer (right side) diff joint from the F103RS soon.
Otherwise I'll have to go with a similar plan mentioned in the previous post... which is some solid custom engineering!

I'll guess that the assymetrical T-bar is to do with centralising the centre of gravity of the motor/diff assembly.
Just spotted something that might address the diff adjustment when wheel changing issue - rather than remove just the wheel, why not just loosen the hex grubscrew & remove the wheel, axle extension, diff etc all as one lump? Ok, dumb idea...
That's actually quite alarming - why the relatively hefty wheel fixings when all that's holding everything together is the M3 hex grubscrew?! There's rather a lot wanging about that a tiny M3 has to keep under control

eddrick wrote:

I'll guess that the assymetrical T-bar is to do with centralising the centre of gravity of the motor/diff assembly.

Good thinking! That must be it.

If I take off the whole diff joint instead of just the wheel, at least the diff can't accidentally drop on the floor.
That's why I like the Group C hubs. And the configuration the F103GT uses btw.
The grub screw will stay in place I think since the axle is flattened in the right places...
But it's definitely an elaborate setup.

Just wondering what wheels you want to use with this? If you like the c cars size wheels dont for get about the Indy wheels,they are the same size as the c car wheels,but are one piece and lighter weight than the c car wheels. But they mount like the F1 wheels with the bearings for the diff in the wheel.
If you are sticking with the bigger c car size wheels,which look best for the c cars,you should thing about useing a F104 gear box,The f104 has the same size(tall) wheels but the gear box sides are different. It moves the axle up and lowers the motor. SO you do not have to use the plastic spacers that are shown in the c car instructions.Getting the motor lower has a huge effect on the handleing of the car.
The F104 gear box is also height adjustable like the F103.

I really hope you run this,maybe not with the nice rare F40 body but other than the body all of these parts are easy enough to get. If you cant find something let me know,or if you need tuning advise. I can help out.
The only really bad things I see is the lack of a rolling damper and the pivot ball t bar holders. The rolling damper is a must and the pivot ball t bar holders will take away one very important tuning setting and they dont work like the should even with your tweak screws. I will take some pictures of my chassis to help you out of you need.

Thanks for all the info.
I have a height adjustable (Cross) gear box on my Group C actually. Really nice black aluminium.
Still in the process of setting up the car. Waiting on an F103 that I will use some parts from...
That way I can fit the torsion plate also.
The F40 is in a nice condtion but not great. It had an accident before I got it so it's cracked at the wheel arches.
Can't hurt too much running it a bit. At least for the initial video footage.

I wanted to show you the difference between a height adjustable F103 gear box and a F104 gear box. YOu can see that the F104 gear box mover the rear axle higher. SO it like have the spacers from the c car built in. But when you add the spacers to the gear box like on the C car it moves the motor up in the air. If you use f104 box the axle is the same height as the C car but the motor is now low where is should be. It really makes a big difference in the performance of the car. It can go from spinning out all the time to understeer just buy getting the motor lower.

Aha, thanks! Might have to get me one of these to experiment with...

F103RS in da house! With a Toyota GT-One body.
The car will be donating some parts to the F102 and will become F103GT-ish later with new parts.
Picture will follow...

Nice looking car, That blue alloy shock mount only comes with the pivot ball battery holders. Its a nice piece if you are looking to do a Tamiya Blue type chassis.