DT-02 / DT-03 Front Hex Conversion

[ChrisRx718 4470]

Hopefully this is in the right place, it makes more sense than in the 'Builds' section since it's really just a modification...

We've been through a lot together, me and my £50 DT-02. A lot of batteries, that is.

It's probably my favourite runner. They're tough as old boots and have really predictable handling, with a tight turning circle, decent ground clearance and good weight balance for jumping!

Problem is, there aren't many on-road-suitable tyre options for the DT-02/03 buggies. There's the Carson All-Terrain wheel set, which has sold out pretty-much everywhere during the Covid-19 lockdown. These are generally black or chrome wheels in a design which I don't particularly like, though, and you're kinda stuck with them.

The other option is the front wheels of a Tamiya QD touring car from the 2000's, which had twin 1150 bearing front wheel fittings, based on a touring-car sized 52mm rim. Then you're kind of stuck with the CC01 range of tyres, or some crawler tyres, which aren't really appropriate as they're generally too soft.

There is the pricey option of Tamiya Street Rover wheels and tyres, but your tyre options are limited and as said, this is an expensive route!

So what about hex front wheels?

There's this option from GPM which I tried originally:

Unfortunately, they just don't work. The wheel nut still has to be tight against the wheel, clamping it in place. The only way the wheels can 'freewheel' is to back the nut off a couple of turns. Then you'll find the nuts will fall off when you run it. Not good, sorry GPM.

Some internet searching led me full-circle back to the TamiyaClub website, where a 2017 post from member 'Pininy' (who sadly doesn't seem to be registered on the forum) listed some parts and a small modification to convert the front of a DT-02 to hex-fitment. Massive thanks to him (or her??) I'm just re-documenting how this all goes together below.

Parts required:
3Racing FGX-107 - Sakura FGX Parts Part G
3Racing FGX-124 - Heavy Duty Wheel Axle For 3racing Sakura FGX
4x 850 ball-bearings (5 x 8 x 2.5mm)
2x 2x10mm pin (for hex) - Tamiya 50594
2x 5mm ball connectors - Tamiya 50592
4x 5mm ball end (short) - Tamiya 50797

Option parts I used:
Tamiya 53828 DT-02 Turnbuckle Suspension and Tie-Rod
2x 22mm hinge pin & e-clips
2x 1.5mm x 3mm spacer

So these are the current hop-up tyres I had fitted after wearing-out the kit ones last year:

I think they have a little bit of life left in them if I use them on grass!

Here are the wheels and tyres I want to fit:

DF-03 front and rear wheels, which are obviously 12mm hex fit.

Fitting the rear wheels of course is very straightforward:

And there are no issues with clearance etc.

The front end has to come apart next:

There's quite a lot of wear on that little pin-screw which holds the front upright in the C-hub.

I decided to replace these after finding that 3x22mm hinge-pins fit, more on that later.

You need to modify the front C-hubs to get enough clearance for the new knuckles. I did a quick and simple job with a Dremel, you could likely do it much neater if you had the inclination!

You can even see all the black debris from the grinding tool un-ceremoniously sprayed up the side of the body! 

Here are the new parts required:

They go together like so, I have fitted the 5mm ball connector to the pin closer to the axle for maximum steering angle:

I strongly suspect that the axles can be the commonly-found M-Chassis items from Tamiya, but I didn't have one to-hand in order to check sizing etc. But they fit in exactly the same manner, so I can see no reason why it wouldn't work. 

This is it all fitted. I used the 3x22mm hinge pin, retained the small metal shim at the base of the knuckle (as per DT-02 standard instructions) and required that 1.5mm blue spacer to take out the vertical travel of the pin.

At this point I fitted both sides and re-connected the steering tie-rods. Unfortunately, I had an un-holy amount of toe-out, as the arms were now too long (the ball connector has moved inwards from the stock items).  

I replaced the adjuster ends from the 53828 hop-up set with 4nr of the standard 5mm short adjusters, like so:

 

Ta-da:

Then it was time for wheels-on. I haven't taken any pictures but it's naturally the same as the rear-end, 2x10mm pin goes into the hole on the axle, 12mm hex over the top (included in the 3Racing parts) then the wheel and the locknut.

And this image hopefully shows why you have to modify the front C-hubs for the knuckle to clear on full-lock:

Then you're ready to go:

This opens up a huge aftermarket for optional wheels and tyres, especially at 2.2" buggy size. I have some road slicks on order which I will fit to this and update with some pictures.

Crucially: there are no clearance issues front or rear, and whilst you have a smidge of added ground-clearance with this setup, the chassis still bottoms-out before the dampers reach full travel, thereby protecting those precious shock towers!

[Aerobert 2143]

Thank you for this detail conversion description, the result is looking really good. Does this conversion have any effect on the track width?

[ChrisRx718 4470]

I'm not really sure what the front tread was originally, I think Tamiya measures to the centre of each wheel. Just measured this setup at 215mm. Front wheels sit pretty level with the back ones in terms of width.

Overall front width is about 248mm.

[Nobbi1977 1793]

I think I will try this with alloy c hubs, they should take the modification with less issues when I hit a tree

[Carmine A 2046]

Brilliant! I've been looking for a solution like that for my 2010 HB. 

I had found another method of doing this, with Traxxas Bandit parts, but it has you replacing the Knuckles and Chubs. This looks easier, simpler and cheaper! 

..... And I really don't want to give TRAXXASS my rarely obtained money.

[ChrisRx718 4470]

I can't take any credit, just wanted to document it better than the grainy pics on Tamiyaclub main page.

I hope to take it out for the first time on its' new wheels today, provided it doesn't rain and I get these CAD drawings done for work before then 

[nowinaminute 2815]

On 6/5/2020 at 9:09 PM, ChrisRx718 said:

There's this option from GPM which I tried originally:

Unfortunately, they just don't work. The wheel nut still has to be tight against the wheel, clamping it in place. The only way the wheels can 'freewheel' is to back the nut off a couple of turns. Then you'll find the nuts will fall off when you run it. Not good, sorry GPM.

I have some of these and they work fine (to my surprise) The nut snugs up to the non threaded part of the shaft and leaves enough space for the wheel to turn. Did you drill the hole in the wheel out so it doesn't touch the shaft?

No doubt the replacement parts are a superior option but I was pleasantly surprised by the adaptors. I've been using them with monster wheels on my daughters Kumamon buggy for weeks now with no issues.

[Jontea 334]

Just got my Sand Viper back off a friend (loaned it to him), and I'm after doing a similar conversion as I want to run some Schumacher Honeycomb tyres on it, in the larger front width (4wd). As you state the rears aren't a problem, just a straight wheel swap. Think I'll go down the Fastrax 12mm front adapter, see how I get on, but if they're **** I'll certainly use your method.

Cheers for the detailed pics and taking the Dremel out, love to see a bit of fettling.

[pininfarina 1009]

Good job on the documentation with pictures :-)

 

Pininy - Pininfarina for short

[kwkenuf 184]

Despite the hate for the other T-named rc brand,  I thought I might post this for those that are a little more open minded...

This is the front of my 2wd Traxxas off-roader.  All the front ends of the 2wd models (Rustler, Slash, Bandit, Stampede) use the same caster block (C-hub in Tamiya speak), steering block (knuckle), and axle arrangement.  It looks like this could be easily adapted.  The c-hubs on this are turned 90* compared to the Tamiya,  not sure how that would affect things.  The width of the bottom mounting flange is about 13mm on these c-hubs.  I personally have a couple of 2wd models with this setup,  so I would be inclined to at least try this setup when I get my DT03 together.  The one big downside to this however...  the stock c-hubs are notoriously weak.  It is the one must-do upgrade,  imo,  when you get a 2wd model.  The c-hubs flex,  and in turn bend the kingpins that go through the knuckle.  Aluminum c-hubs (caster blocks) are a must,  at least if you have a Stampede,  which is what I have.

Barry Sheene did a conversion using Kyosho parts that is very intriguing also.  I would be very apt to go that route.  I am sure you could adapt about any brands parts,  as long as the setup is the same.  There is no right or wrong when it come to this.