19" touring / drift wheels

[Mad Ax 9310]

I often find myself disappointed by the selection of wheels available for touring and drift cars.  Things are better than they were, but one of the best brands for choice and availability was HPI, but unfortunately the brand seems to be in continual trouble and AFAIK its future is still in question.  There are now some great new manufacturers on the market but it can be a lottery getting the right wheel at the right time and the right price.

What could be better than wheels on demand?

It was @CarterTG's thread on wheel printing that encouraged me to buy the Elegoo Mars in the first place.  If he can get a successful wheel print, then so can I, right?

This thread will document my progress from prototype to finish or failure, and point out any issues along the way so anyone working along with their own resin printer will be able to learn from what I've done.

So, with my future as a wheel designer laid out before me, where do I begin?

First - with an idea.  Ultimately I want to have a range of wheels in a range of offsets, so I began by designing a rim and hub based off a standard Tamiya wheel.  26mm wide, with inner and outer beads and a 1mm wall thickness.  The hub is oversized but that allows me to subtract from it later to make unique face patterns on later designs.  Offset is a standard-ish +3mm, that is the back of the hex is 3mm towards the outside of the rim from the centre.  This seems to be about right for a Tamiya wheel.  Actually the measurements I took from a standard wheel weren't absolutely the same, but the wheel was used and my caliper is cheap so I wasn't expecting 100% accuracy.

More to follow after I grab a coffee...

[Mad Ax 9310]

So, in my creative studio time yesterday, I decided to start work on a proper scale rim.  I didn't go for massive detail as I wanted to prove the concept, but I also wanted to do a little something that stirred the soul, so I would get that special feeling when I held the finished product in my hand, that this was all going to be worth the effort.

The first thing I wanted to do was a 5-spoke deep wheel for my S15 shelf car.  Tamiya made a beautiful body with the Coppermix Silvia, but they very badly let themselves down with the wheels.  They take this aggressive drift-style bodywork:

And turn it into this shopping car:

 

To get a nice curve on the spokes I would have to move away from basic shaping and start using forms in Fusion 360, so I followed this excellent tutorial from Youtuber Paul Sohi:

 

So - after a little bit of work (a lot less than I expected) - I present to you - the prototype v3 version of the SCRAPSpeed Taro +3:

I still consider this a very early prototype - so, no filleting around the sharp edges, no recess for the wheel nut, no final detailing, but a lovely curved spoke with some nice detailing.  There is ribbing behind the spokes to add strength, although there is space for a bit more (comparing it to a standard Tamiya wheel).

[Mad Ax 9310]

So - with a prototype wheel in the design studio and a 3D printer sitting dormant on the desk, I figured I might as well print off some physical types to play with.  Best-case scenario, both wheels come out well-formed, survive the curing and trimming process, and allow me to do a live run on solid ground to see if they stand up to abuse.  Worst-case scenario, the prints fail and I can't work out why.

Anyway - I've been having some issues with inadequate supports, so for this latest print I turned the support settings right up.  My last print had some detached supports with a 1mm ball, so I increased to 2mm.  It'll waste more resin and leave uglier marks on the print but, for the first time ever, the print completed without any detached supports.  It took just under 5 hours to print 2 wheels, with a 6s exposure time.

Poor photos, I know, but here you can see a definite problem.  From the back it looks OK (apart from being way overkill on the support material) but from the front - one of the wheels has split open.  I think what's happened is the build plate has moved, probably due to the print getting stuck to the FEP.  I must have left the securing screws a bit loose when I set the plate.  They were 'tight', but they were not 'that tight'.  Oh well.  One wheel came out more or less OK - there's a little bit of distortion but it's mostly round and only had one area where it was missing a support, which hasn't affected it in any way.

[Mad Ax 9310]

The problem with all that support material is the amount of finishing required.

Yeurch.

Also some supports have bonded to the rim itself.  I tried to trim away one between the beading and the rim cracked.  I've mentioned on my G6 bumper thread that the resin can be brittle.  Obviously one issue is the 1mm thickness - I will beef it up for the next print.  Another is the 45 degree print angle - it's not right for this design.  I need to rethink.

So - I don't have a working prototype, but at least I can clean it up a little and see how it looks.

I always print with the visible face down - that way the visible face needs no finishing.

I dunno about you, but I think it looks great.  That line across the spoke is the Z axis line where the build plate shifted.  You can see where the rim doesn't line up with itself.

[Mad Ax 9310]

I figured, if the rim wasn't useable, I could at least do some destruction testing.  So I picked up a wooden bar from my desk and gave the rim some wallops.  Not overly hard to begin with, probably not as hard as hitting a track barrier in 17.5 blinky.  It took a few gradually increasing wallops in various places before the beading cracked off.  It's not an empirical test but I don't think it's as touch as a Tamiya wheel.  I may try my next print at a very brief 4 or 5s exposure to see if it improves toughness.

These photos show a standard Tamiya tyre fitted.  The missing bead on the front face is where I hit it with a wooden bar, the missing bead on the back is the split from trying to remove a support.  As you can (hopefully) see, the rubber tyre edge fits very neatly into the bead.  That's a shame because I'd like to add some filleting around the bead to allow me to print with the back of the wheel directly on the build plate...

[Mad Ax 9310]

So - was it worth it?

Well, obviously there's still work to do.  If I can do a vertical print then I save myself a lot of finishing, but I have to watch that the bead doesn't distort.  I don't think I can have any support material around the beading because it's too hard to remove.

I don't think Elegoo resin will ever be suitable for racing.  There are tougher resins on the market and I will need to experiment with them.  With the design flaws ironed out, this resin will be fine for the shelf and might be OK for drifting, where the impacts are slower and lighter.  I will try to get some drift wheels printed to test on my next drift outing.  (The downside is I may crack the rims getting the plastic tyres on).

But - I will let these pictures speak for themselves.  With a bit of work around the hub and a cleaner print angle, there's no reason why I can't give my Silvia the shelf rims it has deserved since I first painted it over a decade ago.

[Alexei 547]

my favorite maker of wheels is Yokomo, and HPI. and i have noticed some wheels by MST that i also like. but its not like there is heaps of wheels i like, of what is available.

did you put any photos in the thread? im not seeing any.

[Mad Ax 9310]

18 hours ago, Alexei said:

my favorite maker of wheels is Yokomo, and HPI. and i have noticed some wheels by MST that i also like. but its not like there is heaps of wheels i like, of what is available.

did you put any photos in the thread? im not seeing any.

Yokomo have got a good range, although I've not bought any so far.  MST have some great wheels for drift, including some with adjustable offset, which is quite possibly the neatest idea in the entire universe.  I have a set on my RMX 2.0S.

I put a lot of photos up, they are hosted on TCPhotos.  Sometimes they take a while to refresh for me.  I'm pretty sure they're set to public.  I'll check from an anonymous session...

[Mad Ax 9310]

Hmm, have just accessed this thread from another browser and I can see my photos.  Odd...

[Alexei 547]

it was my browser doing stuff. i tried another browser and could see the photos. the red Silvia is pretty dusty in the last photo

[Mad Ax 9310]

The Silvia is filthy, I'm having a terrible dust problem in my studio and have abandoned my shelves for now until I can come up with a solution.  The Silvia and the Primera are so dirty they aren't worth boxing up until I can clean the studio and put them back out on display