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Hex conversions for Tamiya bearing wheel 2wd buggies

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A bit niche but this keeps coming up and it’s hard to search exhaustively for all the varied options. So I thought I’d dedicate a thread to try to gather those options together. Partly because I am researching them again for my own next mods so I thought why not put that in one place. Many of the options will be cross-compatible across models, and others will require a bit of filing or a spacer or two regardless. Fitting a different C-hub into whatever arms are in your model depends on the model specific c-hub width – this is where the filing/spacing comes in. Other than that it seems to me the discussion is not really model specific. Myself I hope to home in on a good solution regardless of model because likely I’ll print my own lower arms to suit.

I’ll start with those I've found so far that I or others on here have tried. I’ll aim to update this post as I confirm details.

Schumacher Cougar hex conversion

Tough standard parts, uninterrupted kingpin means axle offset c.5mm behind kingpin (“caster offset”? Not sure terminology). I‘ve been running this for ages on a DT-03 without issues and I pinched it from @matisse. However, my further research below makes this a relatively pricey option compared with TD2, Dirtmaster etc. and a little filing is required.

Parts needed:

Schumacher Cougar hex conversion kit includes bearings and hexes, about £25 if you can find it (I can’t currently)

54244 TRF201 D parts: 11.9mm wide C-hub which fits DT-03 arms (11mm gap) with minimal filing (but it does replace the DT-03 stock carrier, into which the above uprights would not fit - they might in other models though, if the carrier is more deeply cut out to take the rotating upright)

Alternative to 54244 is 51410 – 5deg more caster angle

Kyosho Dirtmaster

Similar in principle to the likes of the Cougar option, readily available, inexpensive, should be tough. I've test fitted it to a DT-03 and it fits. Carrier 10mm wide which is pretty small so it drops straight in to the DT-03 arm with 1mm to spare. Being narrow, if other model clearance in the arms is tighter then at least this one requires less filing than some others. 

Parts required:

UM578 upright and carrier; UM587 axle, all bearings 1050, 3x25mm kingpin, 1.5mm spacer above or below upright, 2.6x5mm truss screw to retain kingpin, hexes. And keep your stock lower shaft assuming it's 3mm (3x25mm in the DM arms).

3d Print to fit existing c-hub

Could be designed standard across any models that share the same bearing wheel upright (DT-02/3, Blitzer, others). Axle will be offset rearwards by necessity to clear the kingpin as per the Cougar option. You could model yourself or @SlideWRX ‘s example might still be available. I might have a go myself at some point. A downside to attempting this is that the DT-03 carrier has very little clearance for the back bearing and axle end to rotate past, which is an annoying design constraint and  plays into the hands of buying both upright and carrier as a set. 

A key advantage, if you're fitting to a model with direct steering, would be the opportunity to design a atm that extends straighter back, to keep Ackermann as stock (or tune as desired). (see note on Ackermann below) 

Parts needed:

3d printed uprights

54183 Axles or similar from eg M chassis

Bearings to suit, probably 2x1050, 2x1150

Hexes

DF-03

Details TBC but it looks like DF-03 arms will fit DT-03, not sure other models. Arms, carriers, hubs, axles, bearings required, a little harder to source than current stuff. @mastino has posted an example and it looks very good.

Commonly available one-piece wheel adapters

These fit on the existing uprights. Although I haven’t tried these many have, but i suspect it's mostly for the shelf. I am skeptical about their use in runners as they are fitted in the order: adapter (with both bearings in) – wheel – nut. So wheel either rotates against nut or has nothing to hold it on beyond the tightness of its fit over the adapter’s hex. YMMV, I don't intend to try these.

Two-piece wheel adapters

Also fitting the existing uprights, but these go bearing – hex adapter – wheel – outer adapter piece – bearing – nut. In principle I think these could work fine because the wheel is sandwiched between two parts which are both rotating with it and that combined system is retained between bearings properly. The product was posted on here a few months ago, so someone's done it, but I can’t immediately find it.

Other options I have not seen done yet:

TD2

I haven’t done this yet or seen it done but I have just researched the parts and am going to try it. It’s fairly inexpensive, parts are current and off premium (2wd) kits so should be nice and tight and a suitable solution.

Axle does not appear to be offset behind kingpin, because the upright rotates around the hub carrier, rather than inside it, with the two connected by separate top and bottom kingpin screws. However it is offset a little outwards, so will I think give more scrub radius than the above options (min offset wheels required I guess). Arm fitment: width TBC, 2.6mm shaft dia. So you need arms that take a 2.6mm shaft or to ream out the carrier. 

Parts needed:

51674 TD2/4 C parts = uprights and c-hubs on one sprue

54183 Stub axles. Also fit various M chassis

51290 King pin screws. Used on loads of models

The above parts total just £9 (plus tax and postage) on PJ, which seems remarkably cheap to me.

19804301 2.6 x 27mm shaft, same as many models inc XV-01, low cost anyway. Or may be able to ream out to 3mm.

2x1050, 2x1150 bearings

Hexes

XV-01

Similar in principle to TD2, also with same lower suspension shaft and would probably take the same stub axle (but I haven’t measured it yet). A minor difference is the top ball connector for the camber link doubles as the kingpin, requiring a 5x3x2.5mm spacer. Other key geometry points look similar. 

Kyosho Sand Master

Similar again, carrier, upright, axle, bearings, hex all come as a single package EZ006. Suspect cheaper plastics and bolt and nut for kingpin from the photos I see but it's certainly a cheaper option.

M chassis front uprights

Only spotted this today from a post by @JennyMo. Potentially a neat solution because common parts and may fit existing c-hub, requiring only uprights, axle and bearings.

Donor could be M-02 or MF-01X or another, not sure,TBC.

A note on Ackermann angles

I think all of these are inboard angled arms, as most are, so they give a lot more Ackermann than a stock DT-03 upright which is straight. DT-03 gets its Ackermann from mounting tie rods direct to servo saver. So my DT-03 has too much Ackermann with all the options I've tried but it drives fine for what it is, I'm no racer.  

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19 minutes ago, BuggyDad said:

Donor could be M-02 or MF-01X or another, not sure,TBC.

I used a M-05Ra one here, just because I did not have a MF-01X back then and did not know at that time they are the same.

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Finding a proper front hex adapter is challenging.  I tried the one piece wheel adapter as mentioned by the OP on my Blackfoot, but they only support the inside of the wheel.  

Another adapter kit which support both sides of the wheel required the outside of the wheel to be drilled out to accommodate a bearing on the other side, something I didn't want to do with chrome wheels.

I finally just went with the one piece adapter and use a large flanged  nut to attach the wheel.  The flange on the nut rests inside the wheel opening.  Not ideal, but kinda works.  

Any proper solution must support the wheel with a bearing from both the inside and outside of the wheel.

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I have tried the GPM one piece ones and they actually worked pretty well!

I was sceptical because like everyone, I couldn't get past the fact that the wheel would be rubbing against the nut, but in reality, it doesn't seem to be a significant issue.

I used them to fit hex wheels and lunchbox tyres all round on a Sand Rover and it worked perfectly well. There was a small amount of slop but you could probably overcome this by adding a little shoe goo or similar between the adapter and the wheel.

I also noticed that the wheel nut will tighten all the way up and reach the end of the thread on the axle so it can't squeeze the wheel, the only downside is it's possible for the wheel and nut to rub but again, in practice it wasn't a problem.

If you wanted a really sturdy setup, you could do the following:

Glue or threadlock the bearings to the adapter.
Glue or threadlock bearings to axle
Glue wheel to adapter

If you do the above, it won't be possible for the wheel and nut to come into contact as the entire wheel/adapter combo will be locked in place and won't be able to move side to side on the axle and the nut will have reached the end of the thread before it can touch the wheel.

I haven't found the need to do this so far, though.

No doubt a true hex conversion would work better, but I was surprised by how good the adapters worked in the real world for everday use.

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2 hours ago, BuggyDad said:

Commonly available one-piece wheel adapters

I haven’t tried these but am highly skeptical as they are fitted in the order: adapter (with both bearings in) – wheel – nut. So wheel either rotates against nut or has nothing to hold it on beyond the tightness of its fit over the adapter’s hex. YMMV, I don't intend to try these.

These apparently requires spacers to work, to keep parts that supposed to work away from parts that are not. I did one dropped on and it just locks the wheel right up.

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One other thing to consider, although it is a more expensive route potentially, is for any wheels which use the SLW wheel/hub pattern (ie. higher quality six-bolt wheels, such as those from Vanquish Products and some other 3rd party wheel manufacturers) is to use the dedicated 'freewheel' hub from Locked-Up RC...

https://www.lockeduprc.com/SLW-Bearing-Adapter-Wheel-Hubs_p_864.html

They are a proper two-bearing hub, which you then bolt the wheel to using the six bolts (like a real car/truck) - I've used these on a couple of 2WD/RWD builds, including the SRB Cage-Racer - which uses SRB front and rear suspension.

i-xkkQMCW-XL.jpg

Jx

 

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8 hours ago, BuggyDad said:

 

Schumacher Cougar hex conversion

Tough standard parts, through kingpin means axle offset c.5mm behind kingpin (“caster offset”? Not sure terminology). I‘ve been running this for ages on a DT-03 without issues

With the Kyosho Dirt Master now released (which looks pretty much an RB5?), the front axle parts are available. Be interesting to know if they just bolt onto the DT03, like the RB5 does, Although, probably a similar price, once you factor in bearings etc..

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48 minutes ago, Wooders28 said:

With the Kyosho Dirt Master now released (which looks pretty much an RB5?), the front axle parts are available. Be interesting to know if they just bolt onto the DT03, like the RB5 does, Although, probably a similar price, once you factor in bearings etc..

Solid looking option. Looks like you need UM578 and UM587. 578 is both upright and carrier so depending on what shafts and screws are needed (not downloaded the manual) you've got nearly the whole package there. 

I note also on searching for this that the Sand Master set pops up also:

https://www.plazajapan.com/4548565201808/

That looks like a full package including hardware. I think I'll pop that into my upcoming PJ order. 

Not seen the Sand Master before. Very BBX isn't it? 

I might go back and edit these options into my original post I think, then as a reference post folk can just go there rather than reading through a long discussion thread. Can you tell I'm the stay at home parent on half term? 😉

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13 minutes ago, BuggyDad said:

I might go back and edit these options into my original post I think, then as a reference post folk can just go there rather than reading through a long discussion thread.

Thats if they work! 

(I know anything can be made to work, but ,made to work with little fuss).

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9 hours ago, BuggyDad said:

Commonly available one-piece wheel adapters

I haven’t tried these but am highly skeptical as they are fitted in the order: adapter (with both bearings in) – wheel – nut. So wheel either rotates against nut or has nothing to hold it on beyond the tightness of its fit over the adapter’s hex. YMMV, I don't intend to try these.

 

These usually need the wheel centre drilled out to the axle diameter so aren’t a non-destructive option. A nylon washer as a sacrifice would stop any unwanted wear. Also depending on the axle they can need shimmed. 

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5 minutes ago, ad456 said:

These usually need the wheel centre drilled out to the axle diameter so aren’t a non-destructive option. A nylon washer as a sacrifice would stop any unwanted wear. Also depending on the axle they can need shimmed. 

How did the hexes I gave you work? Ok with these mods?

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@alvinlwh Magic dude, much appreciated👍 I’ve used them a bit, they work good as they are the twin bearing type. I’d have no issues putting them on touring or buggy wheels but I’d think issues would show on bigger wheels. I’ve not really ran them much as they landed on my hot rod with some HPI vintage rims and that car is way off being finished. I totally thought I had a picture of them fitted up but cannot find it so I’ll maybe sort one this afternoon if my memory works. I’ll put em on the Wild One as it’s a Tamiya, I have them fitted to my custom wide semi-axle. 
 

I’d definitely buy ones and use them as FOR ME it’s so much easier that doing all the work and experimenting that comes with swapping out hubs and knuckles etc, there’s absolutely nothing wrong with that route though if that’s what wanted and I genuinely understand the challenge/reward in it. 

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To test the Dirtmaster option I've ordered UM578 and UM587 from Banzaihobby in Japan by cheap slow delivery, 2 of each, which makes that a gobsmackingly low cost option, like ~£10 a pop after parts stash raid (think for every other required part I have something will do the job). Fingers crossed it fits. I think it will. And it arrives (I've never ordered from there before). I also ordered from PJ the TD2 parts. I have 2 cars I'd like to convert at some time and a future project I'm quite excited about too. 

Fitting the TD2 parts to something makes me wonder whether I can shoehorn some sort of front mudguards on too!

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Oops. I now realise there's an existing thread on this. It's here:

 

DT-02/3 specific but that's not a huge difference with the principles largely shared across bearing front wheel chassis. 

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I took a look at the sandmaster ones - They need a bit of work. page two on that thread, little over halfway down. :D

 

 

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I should probably have checked the manuals before commenting...but isn't there a F103 with hex touring car wheels? And arent the F103 uprights shared with a bunch of cars like the grasshopper and lunchbox etc?  So how is that done? Probably not easily, as why would Tamiya make it easy. Magic, probably

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9 hours ago, Jonathon Gillham said:

I should probably have checked the manuals before commenting...but isn't there a F103 with hex touring car wheels? And arent the F103 uprights shared with a bunch of cars like the grasshopper and lunchbox etc?  So how is that done? Probably not easily, as why would Tamiya make it easy. Magic, probably

Looking at the manual for the F103GT the uprights look like they slot in as a direct replacement for the stock uprights, however, they don't have to clear a buggy carrier vertical inboard of them (F1 arms aren't pivoted so the kingpin just runs straight through them) so I'm not sure they offer anything especially different to the various other similar height uprights about (by which I mean, reasonable chance the DT-03 carrier wouldn't have enough clearance for them either). Part 51229. But they do take 850 bearings inside and out so maybe they're a little smaller than some others. 

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Updated OP to cover Dirtmaster parts I've test fitted, which are good. Also a note on Ackermann, because pretty much all these options have arms angled inboard as is generally required to add Ackermann on steering geometries that maintain a fairly straight line across tie rods and bridge/whatever. DT-03 doesn't because servo saver rotation means the left to right distance between the two ball studs on the saver shrinks as you turn, creating the Ackermann itself. 

This makes me wonder again about a 3d print. I'd be tempted to model it on the DM upright with just its arm changed, because the C-hub slots straight in and the parts are current. 

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3 hours ago, BuggyDad said:

Dirtmaster parts I've test fitted, which are good

Result!

What was the end cost, all in? 

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I've dropped in two 12 x 5 bearings before on the axle which then sit in the hex. A Teflon coated washer and nut on the outside. 

Not perfect, but they wells run really smooth, and almost free! 

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42 minutes ago, Wooders28 said:

Result!

What was the end cost, all in? 

I got them from modelsport in the end:

https://www.modelsport.co.uk/product/kyosho-knuckle-and-hub-carrier-ep-ultima-sb-dirtmaster-2-1350146

And

https://www.modelsport.co.uk/product/kyosho-front-wheel-shaft-ep-ultima-sb-dirtmaster-2-1350155

So ~£16 plus postage for that lot. Plus bearings, hexes, screws, ball studs required on top, all of which I had kicking around.

 

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Tinkering with ideas to alter the front track on my BBX I picked up another factor for these conversions, which is to watch out for c hub height pivot to pivot (and whether there's an alternative top pivot point as there often is). DM is 25mm, DT-03 and TRF201 about the same, give or take. However BBX is 30mm. 

Therefore if I use the DM c hub on my BBX I run the risk of my negative camber reducing through suspension travel, which feels very wrong. 

The reason to use the DM parts in the BBX is because to widen it I have to design new arms and I was thinking I could just design bottom ones, with turnbuckles for uppers. Half the arms and a shape I can be reasonably confident of getting right first tie. Also I'm a little scared of modelling the ball joints - the points of interface are critical and there's a lot more to get wrong in a ball socket (entry diameter as well as ball diameter, plus the need for the material to take the stress of the ball being popped in). So it looks like my options there are either to model a new c hub alongside my new lower arm, or to model new ball joint upper and lower arms instead. 

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1 hour ago, BuggyDad said:

So ~£16 plus postage for that lot

Bearable...🤔

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1 hour ago, Wooders28 said:

Bearable...🤔

I think so, and that's UK proper shop price, so the bits would be cheap as chips tacked on to an order from eg PJ. 

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