F103GT - Correct Pinion?

[ChrisRx718]

Might sound like a stupid question...

I referred to my manual earlier (also available on TamiyaUSA) for the correct pinion to replace on my F103GT.

The Tamiya item is 3515018 14T pinion

The Spur gear is also marked '0.6' so I'm assuming it's a Tamiya standard modular pinion?

The reason I'm confused is that I can't find an aftermarket steel alternative, I also can't find a gearing chart like you get in most manuals at the step during the pinion installation, so if anyone knows of anything online that would be great.

I'm looking to replace the pinion with something a little harder too - possibly an aftermarket steel item.

Much love!

[dutch_rc]

For sure it's a 0.6 mod pinion, the buttery kind for which Tamiya does not have a steel replacement.

Banzai has an alternative though - the item by Square.

Another thing you could do is put on the 0.4 mod RD spur, the T brand does have a range of steel pinions for this.

Strangely enough I only see the 14T as an option in the manual.

Space-wise, you could go up to at least a 17T though...

Gearing shouldn't be too hard to calculate?

[speedy_w_beans]

Here's what you want for a steel pinion: http://www.robinsonracing.com/catalog/one_eight_inch_bore_pinions.html#steel.6mod

The F103GT is a direct drive chassis, so FDR is just spur divided by pinion --> spur / pinion.

If you're trying to calculate rollout, take the circumference of your tire and divide it by the FDR --> (tire diameter * pi) / (spur / pinion)

[AndyForbes]

You can also fit 0.4 spur gears - Part 53900, Tamiya make a range of 0.4 steel pinions too.

Whoops. Just realised Dutch_rc has already mentioned this.

Edited November 26, 2014 by AndyForbes

[dutch_rc]

You'll have more opportunity to the tweak the ratio with 0.4 mod too.

Spur has more teeth so you can pick a slightly closer range with the 20T+ pinons...

[ChrisRx718]

Have invested in the 0.4 mod spurs and a couple of pinions for very little cash from asiatees.

Now just to get my custom-length chassis plates made up...

[svenb]

Now just to get my custom-length chassis plates made up...

What are we planning mate?

I've just this minute ordered a capri zakspeed body set to fit mine.

I will have to trim the body a bit as its 251mm not 257mm.

sven

[ChrisRx718]

I want to make use of the 49400 anniversary Porsche 934 Turbo body, which is 230mm.

If fibre-lyre hurry up and come back to me, this chassis could be really cheap and easy to 'shorten'. It would take 2 minutes of CAD work to make a 251mm version.

[svenb]

I would be very interested in seeing that.

Where abouts is the shortening on the chassis?

Back were the T bar joins?

Sven

[ChrisRx718]

No, further forward. It requires a new top deck and a new lower deck, but it means that everything else on the car remains exactly the same without any modification.

I'll send a chase up now as I haven't heard from them lately.

[svenb]

What your wheelbase measurement on your 103GT mate? just been trying to sort out a 6mm shorter T-bar as its a 257mm chassis and want to put a 251mm capri shell on and checked it tonight and the chassis is 254mm, give or take half a mm.

I've seen a square made T-bar 3.5mm shorter than standard which sounds like its just what i want, so glad i didnt waste time or money.

you going for 24mm or 27mm shorter?

[ChrisRx718]

The measurement I took last night was just over 256mm, so I may take a mm off my custom chassis plates but thanks for reminding me to check.

Just waiting on my Banzai shipment now

[svenb]

The Square -3.5mm T-bar arrived today, says exactly what it says on the tin. Fits the capri body a treat, just need to wait till next thursday before i can have it!

sven

[Superluminal]

Arise from your grave dead thread

 

[Superluminal]

Just bought an old F103 GT kit on ebay to rebuild. Itss got the original 0.6mod 14t pinion made of cheese as described above.

Im looking for larger pinions but need a smaller spur. It seems all the hop up spurs for the f103 available now are 0.4mod.

Whats that all about?????

Assume 0.6mod and 0.4mod wont mesh together?

So I will need to start looking for 0.4 mod steel pinions as well?

[svenb]

22 minutes ago, Superluminal said:

Just bought an old F103 GT kit on ebay to rebuild. Itss got the original 0.6mod 14t pinion made of cheese as described above.

Im looking for larger pinions but need a smaller spur. It seems all the hop up spurs for the f103 available now are 0.4mod.

Whats that all about?????

Assume 0.6mod and 0.4mod wont mesh together?

So I will need to start looking for 0.4 mod steel pinions as well?

The 0.4 spurs/pinions are massively better than the 0.6, harder, smoother and stronger. 

Definitely recommended 👍

[Superluminal]

Trouble is;

I can get this;

https://www.ebay.co.uk/p/2254315826

But now cant find any suitable 0.4mod pinions. They all seem to be about 45 teeth which is mahoosive

[Fabia130vRS]

If this has not been solved. 
 

I had onmy F103 a 93/104 0.4Spur and a tamiya steel 20/21T pinion.

if somebody wishes I can tomorrow see what exactly I have from those two either spare 93 or 104 spur from tamiya and 20 or 21T pinion from tamiya. Will let them go for cheap as I dont need them

[Honza]

1 hour ago, Superluminal said:

Trouble is;

I can get this;

https://www.ebay.co.uk/p/2254315826

But now cant find any suitable 0.4mod pinions. They all seem to be about 45 teeth which is mahoosive

0.4 is compatible with 64p pinions, if that helps

[Fabia130vRS]

Sort of, as I have already mentioned in another forum topic.

really really small differences in 48P and 0.6 as 32P and 0.8. So is 0.4 64P. But I’d rather use 0.4 with 0.4 because it is much much smoother.

[Honza]

48P is 0.53 metric. So it's not "small difference", even 0.5 metric doesn't fit right - according to man who makes precise gears for RC cars, difference under 0.01mm is accetable.

But 64p is 0.397, which is much closer - I guess that injection molded gears have larger variation in dimensions than that.

[Superluminal]

Strangely there doesnt seem to be any shortage of 0.6mod pinions. 

Seems weird that for the hop up spurs they went ftom the kit supplied 0.6 to 0.4mod ones. Is this something to do with the gearing of the standard F103?

[Fabia130vRS]

4 hours ago, Superluminal said:

Strangely there doesnt seem to be any shortage of 0.6mod pinions. 

Seems weird that for the hop up spurs they went ftom the kit supplied 0.6 to 0.4mod ones. Is this something to do with the gearing of the standard F103?

From my experience as I have spend most of time with the F103. With the standard 0.6 gears the car was quite fast to drive on brushed motors. As the gap between teeth is bigger then on 0.4 (but there more of them on the same space), so my idea is that the 0.4 gears are more responsive to throttle commands. That can be experienced on Brushless motors.

[Superluminal]

11 minutes ago, Fabia130vRS said:

From my experience as I have spend most of time with the F103. With the standard 0.6 gears the car was quite fast to drive on brushed motors. As the gap between teeth is bigger then on 0.4 (but there more of them on the same space), so my idea is that the 0.4 gears are more responsive to throttle commands. That can be experienced on Brushless motors.

Ah ok - So it can be put upside into a hedge that little bit quicker. I feel nervous just looking at it - it feels so lightweight.

Looking forward to getting it up and running now as never had a 2wd pan car or F1 before as a runner.

[Fabia130vRS]

3 minutes ago, Superluminal said:

Ah ok - So it can be put upside into a hedge that little bit quicker. I feel nervous just looking at it - it feels so lightweight.

Looking forward to getting it up and running now as never had a 2wd pan car or F1 before as a runner.

I had really fun with them. I also had a F104, but the F103 can fit the F104 front suspension and rear diff so I build a F103 to F104 conversion and a F103LM as my biggest wish was the F103LM TRF chassis.