Close ratio gearset for Tamiya...???
 

Hi all,

given that my 9 speed transmission was about as popular as poking yourself in the eye with a fork,

what would be the interest in a assembled Tamiya 3 speed with a close ratio set of steel and bronze gears and possibly with a extention shaft at the front for the all wheel drive enthusists....???

Re: Close ratio gearset for Tamiya...???
 

A close ratio 3 speed gearset might go over better then a 9 speed. If the calculated ratios were done so that no one needed aux gear reducers, it would be a big hit.

Re: Close ratio gearset for Tamiya...???
 

Rather than re-inventing an already good working 3spd trans.. how about designing a transfer case similar to the HiLift 3spd that will bolt directly onto the exsisting semi trk 3spd with very little modification?

Simply adding to the front of the bottom shaft of 3spd to power front axle, in many short wheelbase applications there is not enough room between the trans & front driven axle to fit the driveshaft squarely with proper driveline angles. The driveline has to come from the back of the trans.

I've been modifiying the hilift t-case to fit my regular semi trk 3spd, but it's a rather pricy option by having to acquire the entire hilift 3spd to do so and then having all the wasted parts left over.. these 3spd's never wear out.

Re: Close ratio gearset for Tamiya...???
 

Hi,
Why put the highlift transfer case on to the truck 3 speed....?
Why dont you just replace the truck 3 speed with the highlift 3 speed.....???

Re: Close ratio gearset for Tamiya...???
 

Here's the link for modding a 3 speed to a high lift tranny. http://www.outcastrc.com/index.php?o...&id=1&Itemid=6
Cheer's, Neil.

Re: Close ratio gearset for Tamiya...???
 

Because the hilift motor/trans is a stacked unit, motor mounting molded above trans, and I like using my 12v dual motor combo in my trks, that will not bolt to the hilift trans.

Re: Close ratio gearset for Tamiya...???
 

You cannot get ratios into the Tamiya box that would eliminate the add on3:1 gear reducers commonly used. The gears would simply be too large.
The 44 tooth used on 1st is the biggest gear that will fit (thats why Tamiya use it) and the 13 tooth that drives it on the counterhaft is the smallest that is practical considering the wear factor and the fact it is also used as a spline for the primary reduction.

So the biggest ratio between the countershaft and the clustershaft is 3.38:1, if you then use the 10 tooth pinion on the motor runnining on the primary reduction gear of 36 teeth that ratio is 3.6:1 .

3.6 x 3.38 = 12.168:1 overall reduction. Then reduced 3 times further by the 3:1 aux reduction box, for a total of 36.5:1 in first gear.

Leaving the 3.6:1 primary reduction aside, 3.38:1 from first gear times the 3:1 aux reduction gives 10.14:1 .....to acheive a 10 to 1 reduction in a single step given the smallest gear you can feasably use has 13 teeth, the driven gear would need 130 teeth, that gear would be wider than the truck.

So acheiving large ratios inside the box to eliminate aux gears is not feasable.

You could add another 3:1 to the primary reduction by adding extra gearing from the motor but that would considerably increase the torque that the counter and clustershaft gears (and more importantly the drive dogs) would encounter.

The Tamiya plastic gears and selector mechanisms are a good set up for high speed use but i doubt they would last well absorbing high torque, so extra primary reduction is not a good idea.

So larger cluster gears are out.....increased primary reduction is out.....
That leaves aux reduction....

A aux reduction that bolted straight to the back of the Tamiya box would need 2 pairs of gears to keep the output shaft at the same level as standard.
That is likely to cost at least as much or more than the aux boxes that are currently used and have no advantage over them.........



These are also some of the reasons why the 9 speed developed into what it is.....

Re: Close ratio gearset for Tamiya...???
 

I have proved it for years that the Tamiya 3spd can handle 3:1 aux primary gearing.

I have a 6wd GL weighted down to 17lbs with 1.9 heavy grip tires pulling a 35lbs bellydump trl up a 12 degree incline for literally hundreds of miles over the last 5yrs or longer.. it's the original trans in that trk & I have never replaced a gear or dog clutch in it. This trk runs an FM radio system that glitches on occassion while under full load, so the 3spd trans can take the shock of an abrupt start/stop as well.

What's nice about transplanting the hilift t-case is the added 2.1:1 additional reduction on the back of trans for a wee bit more torque & slow speed control of the trk. A reasonable compact, lower profile setup. I run the incline in 2nd gear all the time, 3rd gear for bobtailing and 1st for maximum traction in soft ground conditions so as not to slip a wheel & dig a hole.

Re: Close ratio gearset for Tamiya...???
 

Can you get anymore reduction using planetary gearing, like what's in the soon to be released tamiya bruiser tranny????

Re: Close ratio gearset for Tamiya...???
 

I'm just not gettin the big hub bub about all this :confused: I wish someone took a vid of me pullin DP9 Joe's 99 # dozer :confused: stock tamy trans. 75T motor w/3.9:1 reduction that sits the motor above the servos . well maybe saterday someone can take a vid of me shiftin All day long and still walkin faster then it in 3rd . So , what ya buildin ;)

Re: Close ratio gearset for Tamiya...???
 

If a guy is really that worried about the gears and ratios being all wrong, there are other options out there besides designing a whole new gear set. Like Joe said, these stock transmissions are proven.

Re: Close ratio gearset for Tamiya...???
 

Proven they certainly are, but everyone complains about the ratios.


"A close ratio 3 speed gearset might go over better then a 9 speed. If the calculated ratios were done so that no one needed aux gear reducers, it would be a big hit. "

Re: Close ratio gearset for Tamiya...???
 

You sure can,
there are planetary reducers available that will bolt up to a 540 motor and others that could couple to a shaft, but planetary reducers are not what i'm set up for manufacturing wise.

Re: Close ratio gearset for Tamiya...???
 

Ar you saying you want to make something to sell?

Travis

Re: Close ratio gearset for Tamiya...???
 

"You sure can,
there are planetary reducers available that will bolt up to a 540 motor and others that could couple to a shaft, but planetary reducers are not what i'm set up for manufacturing wise. "


sure sounds like it :confused:

Re: Close ratio gearset for Tamiya...???
 

Hi, i originally developed the 9 speed transmission on the advise of someone fairly prominent that is involved in the hobby that it would be well received.

That advise for whatever reason was clearly incorrect.

I have been trying to ascertain exactly what it is that is required and inform what is possible from a manufacturing perspective.

I am keen to to recoup the considerable developement costs of the 9 speed transmission and perhaps a more simple product can do that....??

Re: Close ratio gearset for Tamiya...???
 

If you plan to advertise and sell a product here on the forum we require you to become a vendor. If you have any questions you can check out the rules for vendors or you can PM me and we can talk about it.

Travis

Re: Close ratio gearset for Tamiya...???
 

At the moment i'm just researching to find out what is wanted and what isn't...

Re: Close ratio gearset for Tamiya...???
 

A suggestion was put to me that a multi speed reduction box that would bolt directly to the back of the Tamiya box Might be popular......???

What are the thoughts on that....??

Re: Close ratio gearset for Tamiya...???
 

Personally I don't think we need more gears, expecially if it means having to use another channel on a already full radio