TOPIC:

Grrr stop it! I haven't got the funds & you're making me want one soooo badly! Stupid thing is, I've got nowhere to run something like that, so I don't know what I'd do with it if I had one!

I have a real thing for these on road cars too - and not many places to run it either.
But they're just cool as badword...
Imagine I was given these parts. All so very rare too. What an RC blessing.

The transplant has been done - it's got the carbon rear axle now!
And the Group C (C11) was hopped down to a normal one...
Pics will follow soon.

I wrote:

I think I'll put on these wheels for now and switch to a Group C setup later.
Of which I will show the differences in another technical post that is coming up...

Well, here it is...

Lacking some press nuts for the Group C wheel hubs, I decided to go for the F102 setup.
But I actually like the other structure better...
First of all those parts should be easier to find but the biggest difference is the way the the tension on the diff is applied.
Three generations of on road racers all use a different system.
With the Group C the thrust bearing (for adjusting diff tension) is placed directly on the axle and locked with the wheel hub :


On top of that the wheel is mounted with two screws...
Advantage of this is that you only have to set the diff tension once and the wheel can be removed independently.
With an F101 the ball thrust components are inside the rim and covered with a cap :


This asks for readjustment of the diff every time the wheel is removed...
Which is similar to the setup of an F102, although with that chassis the rim has an separate piece for it :


I'll stick with that for now until I have the other small parts (press nuts) to put some Group C hubs (and wheels) on the car.

More details of the build soon...

Btw - the F103 uses a setup similar to the Group C again - with the thrust bearing directly on the axle :


Putting on a nice 0.4 module racing spur (12 balls!) and the carbon axle that was on my C11 :


But with the wheels on, I found the flex on the T-bar too much so I went back to the simple (unadjustable) setup for now :


Maybe I'll give the construction with the friction plate and the offset F103 T-bar a try later.

Next - the damper and some electronics...

Those are some helpful exploded diagrams of compact ball diffs - a while back I was trying to come up with one for a Mardave banger, & believe me, if you've never seen what's actually in one, it can really stretch your brain trying to imagine how it should all work AND be of a compact size! 1/10 touring car etc ones are easy enough & are usually preloaded either with shims or a small cap screw through the centre (Cos there's no axle passing through them - the drive is taken out via cups & dogbones).
By "Pressnuts" do you mean the flanged M4(?) wheelnuts? - these can usually easily be had as generic items off Ebay or from engineering suppliers if you ask for "Flanged nuts", or "Flanged nyloc nuts" if you want the ones with the nylon insert. RS might even have them, usually priced around 3gbp for a bag of 50/100 for the zinc plated steel ones, or you could go for anodised aluminium ones, but being aimed at the toy car market, they will be relatively expensive (But you probably know all this already!). If you want titanium, I'd guess your only options would be toy car related stuff (Or real race car or fishing etc) or get them oredered in specially from an engineering supplier & be ready for a comedy price tag! I can tell you, a lot of titanium fasteners have to be specially made - eg work by in titanium M16 fasteners for tank manways, & usually have to buy nuts & studding, as hex bolts have to be specially made from hex bar & are horrifically expensive!

It would be interesting to see if the Group C ball diff, axle and wheels could be an alternative for earlier models.
Not for an original rebuild of course but for a runner - like rous2000's Rothman's Porsche...

eddrick wrote:

By "Pressnuts" do you mean the flanged M4(?) wheelnuts?

I meant the 3mm nuts (BA1) that are to be pressed (more pulled) into the hub for the wheels to screw on :


Not sure if this is a more generally available item...

Got some 3mm lock nuts at the hardware store yesterday (at 7 eurocent) because they always come in handy.

Ah, yes, those... They have a proper name, but I can't actually remember what it is... clinchnuts, nutserts, Hank bushes? - they're usually used for putting machine threads in sheet metal - idea is you drill a close tolerance hole, put this threaded insert in then bash the back of it to sort of rivet it in (Alternatively use the proper tool, but that's nowhere near as exciting). The ones you have shown there are the type they usually mould-in to plastic components. Again, pretty sure RS do them, easier to find if you know the proper name though... look at http\\rswww.com part# 827-596

@ eddrick - tank "manways", twatting things with a hammer instead of using the right tool ... you must work for Marshalls?

No, Forbes Technologies. Don't much get in the dirty stuff nowadays, mostly in the D.O. or building control panels. Have a look on their website to get a better idea of what they do.
Twatting Hank bushes (Using a purpose ground punch) is the generally accepted way of setting them if it's not finacially viable to get the proper tool. Having said that, I usually keep a brick within reach if I'm using a hammer on something particularly stubborn (Like cars) so that when I lose my temper, the brick gets it, rather than hurting the bit in question...
Why does "Marshalls" sound familiar?

Mmm... it seems that the earlier F103s used a diff thrust system closer to that of the F101 and F102.
The F103GT (58367) uses the Group C-like parts shown above but the (58229) F103RS looks like this :


Ohoh, now I wanna find out when they switched exactly.
The car is as good as finished. Just the body posts left to do. Will update soon.