TRF415 information needed for Yokomo belt drive conversion

[Dr. Robotnik]

Hi guys,

Sorry this isn't RC10 related but I thought I'd liven up the forum with a project topic.

I recently checked out the Japanese website Time Tunnel on http://www93.sakura.ne.jp/~time-tunnel/06-9-3-1.html. I was super impressed by how they ran all their old vintage racers, some models of which I own.



I was particularly stoked on how they had, modernised, modified and improved their Yokomo Dog Fighter cars. With amongst other things modern electronics and larger wheels.



I have been trying to sell a large number of Yokomo parts without much success and have also been in need of a vintage runner too, so with the great Time Tunnel Yokomo's as inspiration I would like to turn this (the black chassis Wonder Dog Fighter car)



Into a runner/racer, like this



I have managed to get a couple of cheap repro bodies (though wrong style for this car) and after pestering shodog (cheers mate) a whole bunch of new and used spares.



So now that I have (they are in the post somewhere ) most of the parts to restore them, I just need to sort out the missing kingpins, front hub carriers and front wheel hubs. I bought on ebay a set of Yokomo MR-4TC-SD front steering blocks as an experiment to see if they can be adapted to fit the older Yokomo.



I am still in need of kingpins (though I can probably make some) and also the front 2 bolt square hubs (I could only find a pic of the rears ) if anyone has any.



Now onto the exciting part of the project. I would like to change the chain drive to a belt drive if possible. I studied these pics of a guy called Aku san's Yokomo which he has converted to a belt drive.



I managed to translate the captions to the pictures, which mentioned that the belt and pulley were from a Tamiya. The site has since been updated and the Japanese captions are lost so that's all the info. I have apart from some other pics.



I did some ebay searching and tried to find a belt and pulley combination that was available, Tamiya and looked similar to the belt and pulley in the pictures.



I found on the ebay shop (dinball) that I bought the front hubs, that they also sold Tamiya TRF415 front belts and centre pulleys which looked remarkably like the ones on Aku san's Yokomo.



So there you go that's my latest project. I don't know if any of it will work and I still need to determine a way to attach the belt to the front drive system. I ideally wanted another TRF415 centre pulley but the ebay shop dinball seems to be some sort of robot and is not replying to my emails. I was thinking perhaps of buying an HPI One-Way Pulley 15T RS4 Mini (BK), for HPI MT, Mini Pro, Mini, Rally, Sport2, Sport, Pro2, Pro.



but it would be 15T not 16T like the other pulley, is that a problem? Also I don't know if the TRF415 belt would be compatible (tooth shape) with the HPI pulley.

So after all that, does anyone have any thoughts on my project or the compatibility/suitability of the parts I suggested? Any ideas on alternatives?

Anyone know someone selling front Yokomo two bolt square wheel hubs?

I guess that's it really.

Thanks for any comments Good or bad I'd love to hear some comments or criticism.

Ed.

P.S. I forgot to add, does anyone know how the MR4TC hubs attach to the hub carriers (c-mount)? I assume by some kind of kingpin, but I can't find any info. on the web or any king pins. Any help much appreciated.

[terry.sc]

Interesting idea, would be great to see this. The Yokomo was for years what Associated raced in 4wd, so it's as near as you can get to a 4wd RC10

You might want to have a poke around here
http://www.yokomousa.com/newproducts/manualusa.htm
It's Yokomos manuals listing, to see what they make today that could be adapted to fit.

For the Tamiya bits rather than use Dinballs ebay shop just go direct to their online shop http://www.rcmart.com Alternatively try Stellamodels http://www.stellamodels.net

Running the HPI pulley should not be a problem, most belts on Japanese cars usually use the same profile. The only problem would be the different tooth sizes. Running a 15 tooth pulley in front would mean the front axles would rotate slower than the rear, so if using permanent 4wd the rear end will try to push the front wheels along. Using front one ways would mean the car would be effectively rear wheel drive, except when the rear wheels start to slip.

The same size pulley to the TRF415 is used on the TA04 and TA05, there may be upgrade pulleys available for those cars whch might be easier to get hold of. The standard pulleys are plastic which is designed to slot over a triangular shaft so probably not much good for this project. Tamiya also make nice alloy one way pulleys to fit these.[/url]

[Mr. ED]

A project to my heart you got there ed.
Beside Tamiya you can probably also use kyosho parts if you're not finding specific stuff.
For my own builds I usually go for plastic parts since they are easy to modify for fit. Once you're sure it won't need taking off chunks, you can allways replace it with alu still.
Big tip: ditch the old yok axles and put tamiyas or kyoshos: much easier to replace when used and with a standard hex you'll have plenty cheap wheel chioces and spare rubber.

keep us up on how it evolves

[Dr. Robotnik]

Wow thanks for the input guys thats real good of you.

The manuals are going to be really helpful Terry, as this is a new project idea I hadn't thought to even search for Yokomo's website

I'd thought that it'd be a bad idea to run a smaller pulley upfront, but couldn't find another part so was really considering (rushing into) it, thanks for talking me out of it.

I am not used to this sort of project but I think some sort of seperation of the rear drive and the front would be good e.g. a slipper like it has with the chain drive. But I think it'd be easier just to use a one way front pulley if there is one available at this stage (especially if it all slots together).

But thanks for the TA04 and 05 info I am off to search for a front pulley

Thanks for your tips and interest too Mr. ED I would love to find some kyosho axles and use hexes or tamiya axles and use hot shot hubs as I have some interesting wheels for these cars

I'll let you know how the pulley search goes and what I order. The project will only really start when the postman comes knocking I guess.

[Dr. Robotnik]

Oh and by the way I forgot to say dinball replied very nicely last night but unfortunately don't have another centre pulley.

[Dr. Robotnik]

I usually go for plastic parts since they are easy to modify for fit. Once you're sure it won't need taking off chunks, you can allways replace it with alu still.

That's why I picked those Yokomo front hubs, they have a mold mark and a sharp corner exactly where I think I'd need to cut and drill them to make them the same size as the original Yokomo front hubs.

It'll become clear when they arrive

[Mr. ED]

I think that centerpulley exists from another model also: not blue anodised but with the same toothcount.

What is the size of the bore you need?
I have that part and can check the diameter of the hole for you when Iget home from Korea tomorrow.
It's definitely a Tamiya part, but you'll need to run the picture by the tamiya experts if it fits your needs. I don't have the packaging for it anymore. Might be a TGX part.

[Mr. ED]

get your uncle to join: that intruder in his garage is an excellent platform for a similar project

[Dr. Robotnik]

Hi Mr ED

Thanks for saying you'd dig out a part for me, if you have one, when you have the time, that'd be awesome. The bore I need is just the standard 5mm.

I am not familiar with any modern stuff so couldn't say whether the TGX is compatible, does anyone else know? terry.sc seemed to think all the Japanese belts would be the same and thus compatible (I hope this is the case).

As for the blue anodizing it won't matter as it'll be hidden in the front bulkhead. Lol.

Thanks a lot

Ed

P.S. Does my uncle have an Intruder in his garage? Someone better call the police.

[Mr. ED]

Hey, I'm not saying I'll sell it to you

but no kidding that part should be easy to get (with different gearcounts also): I will check the bore size and put up a picture for you.

And yes I bought a few different belts and they all have the same dent size: similar to the 32 DP standards.

I bought several sizes in the past; from Tamiya and kyosho, to have a choice for the length of the car in some projects.

The only things different in dent size I came across are: A&L belts, heli belts and the belt on the optima mid (or option house belt conversion).

Sorry for my mistake: I was talking about ferreti again. His uncle has the
Tomy Intruder waiting for a project like yours.

[Mr. ED]

Bad news: the inner diameter of the pulley I have is 4mm only.
There seems to be enough meat though to drill it out ...

But you' d need 2 of the same toothcount indeed or your moter will just be eating batteries.

I'm pretty sure you can find plenty different teeth count pulleys of this type in the gas section of your LHS though.
I bought mine and put in a thin tube to use as moter pinion for a belt drive. But the 15 theeth was pretty much the smallest I could find.

Another one I found with lees teeth came from an airplanes moter reduction, and I've seen these pulleys on starters for gas engines also...
Man, you'll have fun just finding the parts

Now the thing I'd be most worried about is finding the right belt size, unless you plan changing the wheelbase and use a custom made chassis...
Offcourse you can use belt tensioners to make some samll corrections but the less of those the better, right?

One more tip: the width of these cars is omewhat smaller than todays cars legal limits I think. If you're car is not wide enough you can buy TLT1 widener kits: special axlles with a little more offset. There different options for these: RCCA ones wrote an article and promoted using Tamiya F102 (don't shoot me if the nr is wrong) wide axles. But Kose gives you more choice; they have diffferent sets which let you chooose how much wider your car gets , 5mm, 10mm,...
Basically it's logner axles with thicker 12mm standard hexes.

I can put up a picture of the Tamiya axles and hexes if you want: got 4 of these.

[terry.sc]

All belts in non US cars these days have standardised on the same size, after all if that is the best for the job why would anyone use a differnt size. Belt lengths aren't a problem, you can buy belts in whatever length you want from http://www.hpcgears.com Cheaper and easier if you need spares if you can find a suitable belt from an r/c car, but HPC can supply belts in exactly the right tooth count and size you need. They can even custom make pulleys for you, but those are VERY expensive!

[Mr. ED]

so Ed just need to find an old long one cut in 2 and start shortening it till he knows exactly howmany teeth he needs

[Mr. ED]

Been to the shop yesterday, and I think the TRF pulleys I saw have only 4mm bores also.
I hope you have a way to enlarge the hole to 5mm

[Dr. Robotnik]

Hi guys,

Thanks for everyones continued support for this project I really appreciate it. I am busy sourcing a second pulley and am waiting for parts too so its kind of stalled before its started while I await on the post. Some screws, the repro bodies and bearings arrived yesterday so thats a start. I have also been stripping and rebuilding the chassis too. Here's some new pics

Project 'belt drive' Wonder Dog fighter chassis;



Chassis above shot



Bodies and wings



Decals, screws and bearings



Terry thanks for the info on chassis materials and manufacture, that will come in great help a little down the line.

Mr. ED, I can just drill the hole out on a lathe at work it shouldn't be problem.

Cheers

Ed