Honza

What do you mean? It's a kit, it doesn't come with electronics. You can throw in whatever you need - gearbox has same gears as TRF buggies and battery bay can take lipos. How do you know how good or strong it is, when most people didn't even receive it yet?

I hope you'll have loads of fun with the Pro As other have said, it has PTFE tube going into hotend, so you'll need modifications if you want to go beyond 250C (no matter what sellers or manufacturers say, it is not safe to use PTFE beyond that point) A new heatbreak (part that divides hot and cool part of print head) should be enough - bimetal heatbreak seems like the best option, it should work with Bowden extruder even with PLA, which is usually problematic with all metal hotends - however, I didn't get to test it yet, so I might be wrong with this one. I also recommend to print a filament guide - ender feeds filament from top through horizontal extruder hole, which means, that filament rubs and wears through top of it - filament guide reduces that considerably.

I meant that holes go through XY plane. That's how I printed them - standing on long edge and using shafts with e-clips and nuts to share some forces in Z direction. They'd probably split around holes if I printed them flat, exactly for reasons you mention. Full infill wasn't needed, I just added wall thickness

I think that part of reason why they failed in similar fashion is design - This part is ideal for FDM, as all holes and forces in its application are in XY direction none in Z. Also, original part cracked, but didn't break apart like the printed part. I use ST-PLA (or PLA+), which is less brittle variant of PLA. It has advantage over PETG in better layer adhesion - I even managed to print functional ball diff outdrive out of it, which required some 50kg of tension being transmitted through small volume of material, although I doubt it'd actually worked with power applied to it. But PLA becomes soft at some 60°C and I'm not sure if its properties will remain as good over time - some filament rolls I have became more brittle as they absorbed some humidity from air.

I use my 3D printed parts in a rally car, with lot of rollovers and some jumps - so far, I didn't break any PLA suspension part (front arms took some direct hits, but being a rally car, they were relatively low speed). And when I tried to break one of the prototype part with pliers, it took considerable force. For PETG, I have center part of MF01X printed out of it and managed to brake it - however, during the crash, original rear part cracked in similar fashion - PETG part was intentionally designed with same material thickness as original polycarbonate part to test its strength. As long as you design your parts with weaker materials and lower strength between layers in mind, FDM is usable. Only if you need part that cannot be optimised/strenghtened, is too detailed or needs to withstand higher temperatures, then it's time for SLS prints.

I'm using original ender 3 - it needs careful assembly and manual bed leveling might be annoying sometimes, but it does decent job with PLA and PETG after some tinkering. However, it's Bowden, so it's limited to ~250C temperature - that means you can use PLA, PETG, maybe ABS. I used PLA+ on arms and other parts and it seems to hold well (normal PLA appeared to be too brittle). I even managed to print PETG 0.8 gears with 0.2mm nozzle in a reasonable quality.

Czech here, rally scene originated in Czechia (the one where people chase their cars), so it's quite big around here, although it's been a bit less active in past two years because of "unspecified virus of unknown origin".

Yes, so far, I have similar experience, but this particular part is slightly different, which makes it hard to guess from the picture. But I guess it's designed to be direct replacement of 54500. Yes, in this case, availability is only reason why I'm considering it. It's not even that cheaper, considering Tamiya includes a spur gear. Thanks, I'm gonna order it.

I'm from the Czech Republic So I guess that shipping would be more expensive than buying the part locally. But thank you I know that YR part will work for me, I just want to make sure that the project I'm working on will be compatible with Tamiya parts, too.

Hi, I wanted to buy a #54500 for my project, unfortunately it's out of stock in all local shops - but I found similar part from Yeah Racing, TATT-026BU (I only need the spur holder). Does anyone here have both parts, I would like to know how they compare and if YR part has same dimensions as Tamiya Thank you.

I think that TT02 and other models with 39mm dogbones are even narrower. Edit: Tamiya says 182mm for TT02R with 0mm offset.

You could use TA01 (or similar) knuckles and axles at front - that should give you about 6mm per side - TA02W has been done that way. It'd also allow you to use modern CVDs or DCJs, as TA01 has same wheel axle length as M-chassis

Yes, because way how MB has its driveshaft is equivalent of this dogbone Effectively it's like two universal joints in series, while in double cardan arrangement, they are back to back. I once created a dogbone like this by accident, when I shortened a dogbone by cutting it in half and connected it using a threaded tube. Vibrations were quite noticeable. Edit: now I remembered, that DCJs have four holes for CVD pins - it might be interesting demonstration to assemble them with pins 90° apart.

Position in wheel axle doesn't matter, because 2mm pin wil be still aligned with pin on the dogbone end. A different driveshaft is needed, like this one on TRF420 Notice that here, 2mm pin is rotated by 90° from dogbone end. It may seem counter-intuitive, but it's the larger part of crosspin (edit: Tamiya calls it cross joint), that rotates around same axis as dogbone pin - if you tilt CVD around 2mm pin, cross joint tilts with it in same way, as dogbone pin tilts in groove, so both ends move around same axis. But in "wrong" CVDs, 2mm pin stays perpendicular to wheel axle, while dogbone pin tilts - so each end rotates around different axis. This doesn't matter on onroad car, where it runs near zero angle, but any chassis with longer suspension travel will experience more vibrations, than with dogbones. Yes, this is caused by geometry of a cardan joint. Extreme case is, when you take old style universals from TA02, for example, you can bend them to right angle and one end will rotate freely some 90°, but whole thing is locked. If you rotate whole joint 90°, then other end of assembly can rotate 90° - it basically jumps in 90° steps - this behaviour is less pronounced at lower angle, but still causes vibrations. Two cardan arrangement helps to cancel out this behaviour. Dogbone end creates same oscillation, but in case of MB, it is in double cardan arrangement with same angle on both ends, so it cancels out. In case of FF03, you have large angle on outside and zero on inside, which causes vibration, and extra friction makes it more pronounced.

I'll try, but bear in mind that English is not my first language, so my explanation might not success Try to imagine how universal joint moves - it rotates around two axis, one is fixed ( perpendicular to rotational axis) to driveshaft, second to outdrive. In case of dogbone, you have a pin on each end, which act as axis fixed to driveshaft, while combination of groove and ball on outdrive acts as axis fixed to outdrive. When suspension is high, it creates speed variation on outdrive, which is cancelled by joint on the wheel side. Vibration caused by dogbone end will stay, but since angle there is minimal, they are nearly non-existent. In case of CVD, the axis fixed to shaft is the larger diameter part of crosspin, so it should be lined up with dogbone pin on the other end of driveshaft. However, until recently, Tamiya had lined up 2mm pin, effectively creating equivalent of dogbone with each end rotated by 90°. In that case, speed variation cased by each end adds together instead of cancelling out. But In case of FF03, speed variation is not caused by suspension movement, but by steering, so you need something to cancel out vibrations in wheel - which is what DCJs are for. Difference between dogbone and CVD is small, but CVD is a bit better in terms of vibrations - I gues that's because of lower friction and better force transmission, as dogbone tends to slide in and out of wheel axle, while CVD is fixed.

Dogbones are just different form of universals. Reason why Tamiya's universals chatter even on rear is, that they did them wrong for years, one end rotated by 90°, so instead of compensating vibrations they actually amplified them! I think that only recently, on M07 and TRF420, Tamiya did CVDs in right orientation. CVDs will help to reduce vibrations caused by dogbone jumping around outside cup when you get beyond their capacity, but only DCJs will remove all chatter caused by variation of angular velocity.

It looks like it uses A30 part present in TD4 kit. So it should be really easy to convert to transverse battery on the TD4

There are unused holes on the opposite side to servo mounts on the TD-4 tub - I guess these will be used for TD2 - if they'll only replace L-parts to make it 2wd, steering will be similar system to TD4, as its parts are present on K-parts tree.

It would pop dogbones out with larger angle. I had this issue with a TB-03 back in the day. XV01 and DB01 had same limiter screw in variants with front dogbones.

What is part A30? It looks like some sort of battery holder and couldn't find it in the manual, although it's not marked as unused... Same with B3 - are those parts for TD2? It looks like the front gearbox and kickup plate is on single "L" part tree - will this be what makes a difference between TD2 and TD4?

So this is why TD-4 has blanked holes for transverse battery and detachable front part. I guess that bathtub and rear gearbox will be the same, but front end might be entirely different.

Only other captured bearing I know is 2x6 used in older TRF and TA/TB cars. That one requires 2mm screw and nut. Cageless design uses 2,5mm screw. 3/32 were used in the TRF201 ball diff, as well as TA06 ball diff so I think that TD4 will be no different. They are needed in those tiny 52T/48p gears

@toyolien, @matisse That won't fit into TD4 diffs, it uses 6026 (2,6x6) bearings. Also, I think that these ball diffs use 3/32" balls instead of 3mm

Isn't this one 1150 size?

In this case, difference in module is 0.003mm - I think that's within manufacturing tolerances, so they can be considered identical - but in that case, there's no reason to call it "metric" 64p, it's just 64p.