F104 Rear Wheels on F103

[mtjones83 3]

Hi everyone, 

I'm currently in the process of stripping down my F103RS for a rebuild - it's a 1999 Ferrari F310B (58213) and has been sat in it's box for about 19 years! 
It's in pretty good nick with only some o rings having perished completely and the foam tires looking cracked and hard. Bodywork needs some TLC but it's probably salvageable for bashing.

I want to go to rubber vs foam as it'll get run on tarmac/car park rather than any smooth or indoor surface ... but It seems that F103 wheels and rubber slicks are very hard to come by now; so I'm wondering if it is simple to use rims and tires designed for the F104?

I've looked at the manual for a F104 and it appears the thrust bearing sequence is essentially the same but it sits directly on the diff joint with the wheel rather than being built inside the wheel. Is it as simple as that? Does anyone have experience of putting F104 wheels on an F103?
 

Many thanks in advance,

Mike

[Superluminal 3902]

I think you need a whole new rear axle and out drives assembly for the diff with the thrust bearing and locking nut contained in it with the hex.

I have the same issue on mine so will just continue to run foams for now as i bought a load of parts based on poorly educated guesswork a month ago that i have since found dont really fit properly without buyibg more bits.

In the end i just bought new foam tyres.

[Jonathon Gillham 4697]

I do the other way - F103 tyres on a TRF102 and they swap over fine, but you need to change the rideheight as the F104 tyres are taller.

I also have rubber tyres for the F103. Pit Shimizu make them (I think they may have closed but Schumacher bought them?). They aren't as common as F104 but are available. I just checked RCMart and they have some by Ride and TRG in stock too.

[mtjones83 3]

Hi guys,

Thanks for responses... 👍

@Superluminal what parts did you buy and realise that it wasn't going to work?
I've compared the diff sections in the manuals of F103 v F104 and it does appear (to me anyway) that for the F104 the thrust bearing 'stack' simply sits on the axle with the wheel surrounding it; rather than being fixed within the wheel cap like on the F103; the diff housings appear identical - attached for reference... 

@Jonathon Gillham I've just looked at RCMart - thanks - however I need the wheels as well as the tyres; they only have the fronts in stock; rears are a back order. I've never bought from RCMart before - how reliable/speedy is shipping generally?

On the ride height - which I hadn't considered - would the adjustable motor box/mount hop-up give enough range to bring the ride height back down once on the larger rims?

Thanks again,
Mike

[Jonathon Gillham 4697]

13 minutes ago, mtjones83 said:

Hi guys,

Thanks for responses... 👍

@Superluminal what parts did you buy and realise that it wasn't going to work?
I've compared the diff sections in the manuals of F103 v F104 and it does appear (to me anyway) that for the F104 the thrust bearing 'stack' simply sits on the axle with the wheel surrounding it; rather than being fixed within the wheel cap like on the F103; the diff housings appear identical - attached for reference... 

@Jonathon Gillham I've just looked at RCMart - thanks - however I need the wheels as well as the tyres; they only have the fronts in stock; rears are a back order. I've never bought from RCMart before - how reliable/speedy is shipping generally?

On the ride height - which I hadn't considered - would the adjustable motor box/mount hop-up give enough range to bring the ride height back down once on the larger rims?

Thanks again,
Mike

Looking at the manual the F104 is quite different to my TRF102, the ball diff stuff is all in the diff housing and the wheels don't have any of that, so I can't help there.

I have enough adjustment in the TRF102 to switch between F103 and F104 easily, it has inserts which move the rear axle up and down.  Not sure about yours though.

I have ordered heaps from RCMart and found them to be reliable.  I'm in NZ and have even had a few warranty claims which have been really easy, other than having to ship the products back to them which of course causes delays.  As for shipping, in the current environment they are slow, except for Fedex which costs more.  I have had 2 orders from HK shipped by Fedex and they've taken 5 days each.  

Where are you based?  I have found a few places really good.  RCMart, RCJaz are both in Hong Kong.  Amainhobbies and TQRC in the USA, and Fusion Hobbies, Modelsport and Timetunnelmodels in the UK.  All have been really helpful and had no problems shipping down here, and usually pretty quickly too.

[Fabia130vRS 2098]

13 hours ago, Superluminal said:

I think you need a whole new rear axle and out drives assembly for the diff with the thrust bearing and locking nut contained in it with the hex.

I have the same issue on mine so will just continue to run foams for now as i bought a load of parts based on poorly educated guesswork a month ago that i have since found dont really fit properly without buyibg more bits.

In the end i just bought new foam tyres.

You dont need the blue alu diff to run F104, you need it to put the thrust bearing in the diff.

F104 wheels can be used like the F103 wheels with the thrust bearing inside the wheels.

 

but a F103 with F104 wheels has a rear width of 180mm and front 200mm.

 

that is why it is not going to work.

 

this is my F103 with F104 conversion in order to run F104 wheels. See the front suspension of a F104?

 

[Superluminal 3902]

Im totally confused lol

That F104 diff assembly is completely different to the one i was looking at.

 

[Superluminal 3902]

I didnt realise you could install the thrust bearing into standard F104 wheels

[mtjones83 3]

@Superluminal There has been about 3/4 variations on the F104 since first released with improvements being made at each revision; the manual I was looking at was the original 'pro' which is why it is probably nearer to the F103 config. I didn't realise that later revisions have the contained diff housing like you've shown to be fair. It's actually an approved hop-up for the F103 (link below) too so I'm guessing it was originally released in order to allow standard touring car wheels to be used... 🤷‍♂️ Maybe your purchases won't be a wasted investment now?

https://www.rcmart.com/tamiya-f103-differential-housing-54082-00027659

@Fabia130vRS thanks for the picture - 100% get it now! 👍 I'm keen to keep this chassis as 'stock' as possible so think I'm going to knock the F104 wheels on the head and put more time/effort into sourcing some F103 rims with rubber slicks. The car has been in a box at my mum & dads for 19 years so a few more weeks wont harm if I have to back order etc.

@Jonathon Gillham thanks for the suggestions; I'm in the UK and was only aware of Modelsport in the list you gave. I think I'll reach out to the UK ones and see if they can help source some F103 rims and rubber; failing that I'll look at the HKG shops. 👍

[Superluminal 3902]

To be an honest the whole process of what I was trying to acheive was a proper train smash from the start.

Fabia130VRS was a great help though - I wish id tapped him up for advice sooner.

I woke up one morning and had an itch for a having a Tamiya formula 1 car. I then started my project on a ratio of 0% research / 100% spending lots of money in totally random directions.

Where it went wrong was buying a bare bones used but in mint condition F103GT chassis off ebay not realising it wasnt the same as an formula 1 F103. Then buying F104 whhels and realising the F103GT has 12mm hex rear hubs for touring car wheels. Then buying f103 wheels thinking they would fit. Then realising the diff / thrust bearing arrangement is different still and then buying the f103 hubs which then need a new axle. Then buying some more parts. Then buying a used complete F103 F1 car that turned out to be a bit of dog and had some regular washers glued into rhe rear wheel in lieu of the thrust bearings and tophat spacers (hence the lack of diff effect in order to keep the wheels on)

And then just buying a nib kit F104w ferrari which i should have done in the first place.