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JennyMo

12mm Hex wheel front freewheeling hubs for RWD Tamiyas (and others)

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Howdy folks - this is both an information request, and also a toe-in-the-water regarding the potential demand for a hub to mount 12mm hex wheels on the front stub axles of an SRB / Frog / Wild One etc.

As I'm sure most people are aware, there are commercially available hex adaptors for the rear axles of the SRB/Frog etc. to mount 12mm hex wheels with the correct (or at least similar) offset, but I have yet to find anything similar to mount 12mm hex wheels to the front axles?

I know some people have 'converted' wheels - typically by bonding bearings into the wheel - and of course it is possible to do a simple conversion using a cut down rear adaptor and just greasing the axle, but I was/am really looking for a 'proper job' so to speak - ideally using a pair of bearings to support the wheel...

I understand from SRB Bloke that in the past a suitable front hub adaptor has been available - although am not sure if these actually used bearings? - but in any case, I seem to have drawn a blank so far.

Fortunately, I have a friend who is a dab hand with the CAD and has a CNC machine, and has just ordered a 3D plastic printer too, and I've come up with a design that I think will work very well... using a 1150 and 850 bearing.
However, there is likely to be some set-up costs, especially for a one-off for me, so I was wondering if anyone (and if so, how many) might be interested in a set of front hub adaptors - possibly in aluminium, but most likely in printed plastic - that will take/include bearings so you can fit 12mm Hex wheels all round onto an SRB / Frog / Wild One etc.
Just putting it out there for now...
Jenny xx
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From what I know, there aren't any adaptors available to convert Tamiya front stub axles to hex hubs. I think it's impossible.

Many other brands use hex hubs for the front axles of their 2WD buggys. These axles are supported by bearings, instead of the front wheels themselves, similar to the Wild Willy II and Blackfoot Xtreme.

With this in mind, you could try mounting such front axle assemblies to you car. I think this conversion is more easy done on c-hub type double wishbone front suspensions than on the trailing arm suspension of the SRB.

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I have used Traxxas Rustler/Stampede front uprights and axles on a Hornet before. These use 12mm hexes and support the axles on 5x8mm bearings. It takes a little trimming here and there, but it can be done. Should work on other cars as well.

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For my Mad Bull, I'm trying to adapt a set of these

http://www.teamassociated.com/parts/details/6801/

I need to drill out the centre of a hex because it's a touch small, and I'm not overly pleased at the smaller diameter of the thread (I'm guessing it's an M3 rather than an M4, but not sure yet), but the talon is a perfect fit and it'll allow a hex to be mounted up against a bearing which should hopefully let it spin reasonably (not as good as double bearings in the wheel though...)

I'd much rather have bought a proper adapter though...especially if it allowed the wheels/track to be aligned as per the original. Would pay for aloooominum rather than plastic, and would likely look at 3-4 sets of 2 each.

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I think a lot of people would be interested in this, why not create a project on kickstarter.com and then promote the page across all the different forums that have even a remote interest in Tamiya. I think by doing that you'd easily cover the cost and maybe even make a little from it too. Just an idea!

By the way, I'd buy at least one set for sure!

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Thanks for your replies so far guys.. it is kind of what I was hoping for - that is, confirmation that there isn't something already out there that I haven't found, and that I would in effect be reinventing the wheel.. (aha ha - see what I did there?!)

In reply in general, and specifically to the point GregM raises - yes, I have converted my Wild Willy 2 to both Hex and free wheel style front wheels, using the M parts stub axles, and as you say, that works well on the WWII uprights, but not so well on a more scale type front end you get on an SRB or Frog for example...

And that's my point really, what I am after is a way to [easily] mount hex wheels on an SRB front end, while retaining the original metal arm/stub axle assembly for scale authenticity.

I know certain styles of 'scale' wheels (the Carson set for example) are available with freewheeling front hubs, but you are limited to those designs/sizes, and what I'd really like to be able to do is fit four of the same wheels if desired - I'm currently looking at the 1.9 Pajero style, and/or Hummer wheels for example as I like their scale appearance.

Of course, a front 12mm Hex adaptor would open up any number of wheel options, together with the already available rear axle adaptors (such as RadshapeRC) - although perhaps for commercial reasons, selling a complete set of front and rear hub adaptors would make the most sense?

I have a two-bearing design that will work, and will also allow the bearings to be changed if required - however, the front pair of wheels will have to be permanently adapted by drilling out the centre mounting hole slightly, and having the hub adaptor glued into the Hex.

If you find that solution acceptable, then I will crack on with the prototype, and see if we can't get something together...

Thanks for your advice and support so far!

Jenny xx

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Have you looked at the F103GT front knuckles? These work with a pair of 850 bearings, M06 stub axle, cross pin, and 12mm hex. No wheels modifications are required. They may not fit the Frog or SRB directly, but that's the design direction I would take instead of drilling out wheels.

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Have you looked at the F103GT front knuckles? These work with a pair of 850 bearings, M06 stub axle, cross pin, and 12mm hex. No wheels modifications are required. They may not fit the Frog or SRB directly, but that's the design direction I would take instead of drilling out wheels.

I think somebody did get them to work on a Frog, though - it only required around a centimetre of space between the front knuckle and the ball joint connecting it to the steering rod, but it worked.

Regardless, I think I would be interested in a purpose-built design for a Frog, given how unusual those front knuckles are. I once hoped to fit those 5-spoke wheels like those on the rear of the Frog, Grasshopper, and SRBs all round on an O.R.V. chassis.

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Have you looked at the F103GT front knuckles? These work with a pair of 850 bearings, M06 stub axle, cross pin, and 12mm hex. No wheels modifications are required. They may not fit the Frog or SRB directly, but that's the design direction I would take instead of drilling out wheels.

Thanks Speedy - but that is exactly what I was trying to get away from (although I'be temped if the knuckles were a direct bolt-on perhaps)...

My thinking was that wheels are relatively cheap, and that by retaining the original stub axles of whichever vehicle you want to fit them too (SRB, Frog, Wild One etc.) then you could swap the wheels over with the stock ones whenever you desired with just a couple of turns of a wheel nut wrench, rather than have to change out the knuckles (and possibly more) each time?

The reason for having to buzz out the stock 4mm pin hole on the Hex wheels is so that the wheel nut would sit directly against the bearing, and not the face of the wheel - I know in practice you could back the nut off a quarter turn (if the thread was long enough), but it would still mean the wheel is rotating against the wheel nut, rather than purely on the bearings...

Jx

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Regardless, I think I would be interested in a purpose-built design for a Frog, given how unusual those front knuckles are. I once hoped to fit those 5-spoke wheels like those on the rear of the Frog, Grasshopper, and SRBs all round on an O.R.V. chassis.

I think you could do that by using the centre parts of the Brat front wheels - I imagine they would fit inside a 1.55 tyre as well as the 1.7 of the Brat/Rough Rider?

Jx

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I think that would work, the only disadvantages being that the Brat wheels have 4 holes to mount all 3 pieces v. 5 holes for the SRB wheels, and the resulting setup would run on one bearing each in the front wheels. Still, something worth thinking about...

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I think that would work, the only disadvantages being that the Brat wheels have 4 holes to mount all 3 pieces v. 5 holes for the SRB wheels, and the resulting setup would run on one bearing each in the front wheels. Still, something worth thinking about...

Ah yes, of course the Brat wheels only used 4 screws...

Could you not just use/modify the centre part of the Sand Scorcher or Rough Rider front wheels into the rear outer parts then? - you would have to drill the inner face of the rear wheel to the same diameter (15mm) as the front inner face so the centre part that holds the bearings fits through, but otherwise they should bolt right up...

I suppose the only thing that might be an issue is the wheel offset - that the deeper inner face of the rear wheel parts might rub on the steering knuckles?

Jx

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But Jenny, how else would I justify supporting your project?! :P

If I had those tools, then sure...

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Hi Jenny

thought I would rekindle this thread.

Did you ever get anywhere with your ideas for a hex-shaped bearing?

I have a set of gorgeous RC4WD Landy wheels that I keep thinking would look great on my Scorcher and after doing some searching came across this thread.

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Can someone order a boat load and distribute in the UK?

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I'll just leave this link here....

12mm Alloy front wheel

K

Before you do something foolish like give AsiaFleas or GPM (Got Played Moron) your money. These hexes do not fit and AsiaFleas don't care. You have to drill-out the rims and add shims. They do fit one thing, short course wheels, because short course and DT-03 go hand and hand. No.

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Hi Jenny

thought I would rekindle this thread.

Did you ever get anywhere with your ideas for a hex-shaped bearing?

I have a set of gorgeous RC4WD Landy wheels that I keep thinking would look great on my Scorcher and after doing some searching came across this thread.

Hi NJM'

Yes, sort of - if you have a look at my SRB Cage Racer thread, you'll see the prototype hubs in post #34...

P1020170_zps6ecf82c4.jpg

Basically the principle is the same as the GPM ones Kaylon linked to above (nice find btw. although maybe not according to Kick Hopper?)

Anyway, yes, these prototype 3D printed hubs have a 1150 bearing on the inside, and a 850 on the outside - however, you would still have to drill out the centre of the wheel so that the wheel nut does up against the bearing and not the face of the wheel - for it to spin properly, and also bond (glue) the hex adaptor into the wheel to create a single unit (hence the seating flange) otherwise it would fall off of course...

So effectively the modification is not reversible - you have to sacrifice a pair of hex wheels to become fronts (but then regular freewheeling front wheels are different to the rear set anyway of course) - rather the point of this conversion is so you can have 4 visually matching wheels.

I really cannot see any other way it would work, and work properly?

Jx

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I guess the only other way to make this work properly is to look at the F103-GT hubs that were mentioned above and see if you could design something similar that fits Frog / SRB / Grasshopper / Anything Else and accepts a standard non-driven axle and bearings. i.e. replicating a standard driven front wheel hub to fit the 2wd chassis.

This is just off the top of my brain though and I'm guessing not all chassis have the same mounts (not sure there's space inside an SRB or Hornet type hub for bearings, for example) so you'd need to redesign it for every chassis you wanted to use :(

How is the 3D printed material for bonding, and have you had any issues with bonds coming unbonded in use?

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Drill the wheel out so you can use a flanged bearing , So the hub where the 850 bearing goes into not be so deep .

Put the wheel on the hub , the have the centre of wheel to the same size of 850 & use the flange to hold the wheel &

hub become one . Sorry i'm not good at explaining things well .. Hope you can see/hear what i'm saying :D.

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I have actually printed some adapters but my printer created an un-even surface at the ends which meant if I used them I'd never get them out of the wheels... they did work though and were printed in orange ABS, very sexxy. I totally forgot about them till now. I'll try and see if I can refine the design. Basically I made them as a 17mm adaptor for my Blitzer fronts so I could use 0 offset wheels.

K

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I am beginning to understand the problem now. Of course it is not just the bearing on the hex side that is an issue, but also the nut butting up against the wheel.

I do like matman's idea of using an 850 flanged bearing... that may well work.

I am beginning to come around to the idea of reworking the front arms instead like jeekelmental. When I wanted to convert my Wild Willy 2 to use hex ones up front, I followed the easy path of replacing the TL01 style front arms with ones from the M04. In this you still use a hex on the wheel. It is the arm itself which is supported by bearings and spins freely, the wheel is locked on tight.

I will have another look tonight at how my Scorcher front suspension arms fit and think about how I maybe could modify / recreate them to be free-spinning.

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