toro gearbox video
 

Its been a while but I have it together and have a couple of runs on this now It is using a toro gearbox 106-3956. I had to do some shimming and adding spacers to achive a tighter/better fit and alignment of the gears. It is currently running silicon diff oil instead of grease. This thing is not pretty as I just modified my first build to take this, and that was only function.
[link]http://www.youtube.com/watch?v=BB01gp9QTh0[/link]
In the last pic you can see the tire slip on the rim. It weighs about 30lbs and the tires have about 13lbs of air, going to need to stop the tire slip somehow.


Drewcrew6

RE: toro gearbox video
 

well done gos well could do with the engine moving back just to get mor weight on the rear wheels

RE: toro gearbox video
 

OMG! Drew, that is a very nice piece of craftsmaship! I was reviewing you pics, and the pieces look like there were professionally machined. Very godd and functional design of the chassis plate.

As for the vid, it is also very clearly a functional RC! I guess the only thing that could be improved is the gear ratio. Going with a smaller pinion and larger sproket will correct that, and even improve your acceleration as well, maybe traction too.

In all, very nice work, simple but functional, and everything looks durable too.

EDIT: If you want to add some verticle support to the chassis plate that should be very easy to do. A piece of alum bar the length of the RC but about 1.5in wide should stiffen up the chassis plate and prevent bending if you jump it. All you need to do is cut recesses in that bar for the axles.

RE: toro gearbox video
 

THAT THING IS NUTZ!!!!!!! :)
Well done man thats awesome.....
sounds like she has a MEAN top end!!!!! also looks too scary to get it there lol
i love the way a solid axle just throws it around...... nice

keep up the updates man

:)

RE: toro gearbox video
 

Thanks Guys your responses are encouraging.
If you look close at the front, the supports are 3" steel corner braces and the rolls on pavement are bending them back. Need to do some re-inforcing or redesign. Also the outside front tire is all but collapsing on turns under the weight.
On my first build I made 1 pretty large mistake by incorporating the fuel tank mount into the engine mount so now to move the engine back I need to move the tank also. I considered starting a new chassis plate but if the gearbox fails again that would be a waste since I will abandon the gearbox thing.
Also the engine comes loose on its mounts and rocks around after a couple times out. I have 1 more step down in the sprockets to change the ratio then I need to buy different sprockets to get a better ratio, I considered a jack shaft but those bearings are heavy.
I'm not sure where the breaking point of rotating weight versus overall weight also. To go heavier on the car I will need to address the front tires.I plan on 10" all the way around but the servo is not strong enough, considering the tone servo but now my hours got cut so that will wait.

Drewcrew6

RE: toro gearbox video
 

Less HP and more weight +big tires= lower gearing. Your almost their. A little lower gearing and you"ll be right on . If you had a 2 hp motor you would be their.[8D]

RE: toro gearbox video
 

So what gear ratio am I using bsrman?

RE: toro gearbox video
 

This is a guess from my part, but if you can, try for a 9:1 gear ratio. I guess this because my FG MTs have a 10:1 ratio and the Zen of course approaches 15K RPM. For the Ryobi, it will turn less of course, and since you driving wheels are large diameter, maybe 50% taller than a typical 5th scale MT wheel, this is why I am guessing a 9:1 ratio.

RE: toro gearbox video
 

Yeah 9:1 sounds about right. Good work mate [8D]

RE: toro gearbox video
 

9:1 is good for a Zenoah with 2-3 hp and 8" tire but not with 1 hp and extra weight and 10" tires has to be much lower.[8D]15:1 to start then move up a little.[8D]

RE: toro gearbox video
 

Drew,

Man, nice work.....looks like it runs perfectly fine the way it is.......just get a couple matching tires and it'll be sweet. Keep up the great work, can't wait to see it finished!

RE: toro gearbox video
 

nice work...

RE: toro gearbox video
 

Nice,my ratio is 7:5:1 and im using 5 inch tires with 26cc 1.5hp,and it seems to be fine,i will have to get a video.

RE: toro gearbox video
 

Thanks guys,
Naynay Can't wiat for a video of your build


Most you guys are very close, in that video it has 8.73 : 1 the next step I can go is a 9.6 : 1 . Gonna try that next time out. I think the clutch is slipping a bit yet but I did not have my temp gun to check it, somehow I need to make the clutch stronger. I also need brakes on it yet. Eventually the front will have the same tires as the rear but my servo won't handle that so i need to hold off on that. I also need a cage to protect the plug.


Drewcrew6

RE: toro gearbox video
 

The clutch is slipping because the engine can't reach the RPM needed to turn 10" tires. You need to double the gearing for the clutch to stop slipping and accelerate faster.[8D]

RE: toro gearbox video
 

yep, most likely. But I do remember from a physics lecture over 20 years ago (funny how some things stick in yer mind)
to be self propelled, a ratio of 6:1 is required

looks cool ,man

RE: toro gearbox video
 

Only for low speed applications and lots of 6HP. Less require lower gearing 18:1.[8D]

RE: toro gearbox video
 

I had to put a cheesy cage [1 x 1/4 alum bent over car mounts on front and rear] on it as the center of gravity is to high and it keeps flipping, resistor plugs get expensive real quick. So far about a total of 1 hr of runtime and gearbox is still as tight as when i assembled it. Last time out I noticed something wasn't right and was bringing it back to me and the left tire went in its own direction and stopped at my feet from about 200 ft I had to walk to get the truck though, wish it was the other way around lol.
The rear tires are not balanced well and that loosened the loctited setscrews holding the one and I lost the keyway. I carried a spare for everything but that!

Drewcrew6

RE: toro gearbox video
 

Just an update
About 3hrs on gearbox now and still running tight as when assembled. Now ineed somway to hold the tire from spinning on the rim have sheared 2 valve stems off the tubes.
Thinking either tire glue like a regular rc tire or run a few small nut/bolts from the inside out thru the rim right in the bead of the tire. I would have more but I HATE the cold and the truck is hard to get moving in snow, I need better tires.

Drewcrew6

RE: toro gearbox video
 

I think sadly that any tube style tire will spin under weight, and power. Try looking into turf savers, thats what I plan to get. You can get some that have decent tread on them, and I believe they do not have tubes, this way you get a better bead seal. Otherwise things seem to be going well for you!

RE: toro gearbox video
 

Kind wish I could go tubless but the rims are 2piece maybe in time I will spend money for 1 piece but I believe that gopeds have tubes and they don't have the sipping issue, wondering how they dont

Drewcrew6

RE: toro gearbox video
 

hey stranger, wonder if u could fill the tires with great stuff foam or something equivelant? i too will need to find a solution to this small dilema[>:]

RE: toro gearbox video
 

Hey,Hey
I thought about foam but I think it would be to easy to get the tires to be solid like, since that is my only form of suspension that would not be good.
For the tires I just dropped 2 8/32 countersink allen head screws from the inside and the nut on the outside, straight across the center of the rim from each other. Towards the frame of the truck. Loc tite of course and problem is taken care of. I had it out for about an hour yesterday and beat the thing really hard. No slipping tires!!!! Even with only about 2 pounds of air!

Another change I did was mount part of an old broken cordless drill. The part that holds the battery. And a 5 volt regulator. Now I can just drop a battery from my cordless stuff and go to town for hours - if the truck would only be that reliable. I plan on getting a 6 volt reg in the future.

Now to get back to the frontend. When I was out yesterday the servo saver I bought failed completly, the 2 pieces just spin in each other. Time to make my own I guess! and take care of reinforcing the knuckels.

Drewcrew6

RE: toro gearbox video
 

Failed servo saver? Wow, that must have been a pretty hard hit to make it simply slide without doing its thing.
Is is a cam-type servo saver? I can tell from the pics.

Can you post some pics of the busted servo saver?

RE: toro gearbox video
 

Good call Savage

I tore it apart and it has been abused. But it is actually still functional, well it was. When taking it apart 1 of the springs went sailing but it was missing the 2 plastic ends for the spring. They might have come out a while ago as the screw holding it on the servo snapped the head off, didn't really look when I repaired that. When the screw broke it also stripped a gear inside. this is on a Futaba s3302.

This saver was a good match for the servo but they are both underpowered for this truck.
Working out a wiper motor for the next truck, this one does not have enough room for it.

Don't have a camera right now. But this is the one I have just in yellow.

Drewcrew6