alucard13

I know this is going to be a dump question, but exactly how does the 2 speed work on the TC3? On the clutch bell i have 2 gears that are screwed onto the bell and they move both spur gears at the same time. So if this is the case, how does it shift. I did notice when i was putting it together that there is another set of cluth shoes that are attached close to where the brake is and drive shaft. when that engages does it make it spin faster or what?

Also, what is the diff between the TC3 and NTC3?

fastharry™

iTrader: (4)

go back to your instructions and look at the diagram....see where the 54 tooth gear attaches to a hub?..that has whats known as a one way bearing......to keep it simple...those shoes expand,the smaller gear engages and the first gear simply rides on teh shaft do to the one way bearing's ability to grab one eay but siort of coest on teh shaft when needed.....

I suck at explaining stuff...but if you look at the picture,and understand the 2nd gear spinning faster,you'll get it..

alucard13

you make perfect sense. even though both gears are moving only one can be angaged at a time while the other just moves freely. is that right?

fastharry™

iTrader: (4)

right..since the one gear is being driven at a faster speed(2nd),the 1st gear sort of just rides on the shaft...

the tc3 is electric..the nitro is,well,you know...



www.rc10.com

fastharry™

iTrader: (4)

if you have any other questions,post them in the nitro tc3 forum..we'll be glad to help..

IMPACTPLAYR

iTrader: (7)

I posted this on the first thread, but here goes agian...........


This can be kinda tricky to explain.....

Yourtheory would be correct, but you forgot the one-way bearings inside the clutch....

each gear gas it's own independant one-way bearing , both facing opposite directions. As the engine starts to rev-up gear ones bearing locks to the shaft and begins the acceleration process, weanwhile gear 2's one-way locks in the other direction allowing the gear to "freewheel" on the shaft not being engaged, infact that bearing never engages......

Now as the RPM's come up the 2 dspeed clutch engages gear 2 at a shaft RPM level you determine, in trn this locks gear 2 to the shaft increasing the prm's of the shaft. at this point the shaft starts spinning at higher rpm's than gear 1, so the one-way bearing disengages or unlocks and allows gear 1 to turn at lower rpm's than the shaft is turning.....

The Nitro 2 speed is quite complicated if you don't understand how the inner working parts actually do their thing, but quite simple once you understand how it works......

The nitro 2 speed would be totally mpossible if it weren't for one-way bearings......

fastharry™

iTrader: (4)

my tc3(and my HPI's)only ahve a one way on the 1st gear...the bearing on the 2 sp housing is a ball bearing...

the 2 sp hub doesnt need a one way.its not engaged untill the shoe(or cam asembly on teh HPI 2sp) comes out and engages the outer hub..

Jon Carlson

iTrader: (48)

There is only 1 oneway bearing on a NTC3 (unless you have a oneway in the front diff that is) it is in the 1st gear hub. 1st Gear spins and gets the car moving then when the shaft is spinning fast enough the 2nd gear shoes engage and overdrive the 1st gear so then the oneway in the 1st gear hub spins free like a bearing. There is a regular bearing in the 2nd gear hub. The gears on 1st and 2nd gear are always turning at the same speed and together. They are never moving at different speeds because they are both attached to the same clutch bell housing and the gears on the clutch are locked onto the clutch. If there were two oneway bearings, one facing each direction, the car couldn't freewheel. Is that any better?

Jon

modellor

For someone giving such a high detailed description of the complexities of a 2-speed gearbox your lack of knowledge simply amazes me.

1. Their is only and will only ever be a single one-way bearing in any 2-speed gearbox. The bearing on the second gear is a free bearing which will rotate freely in both directions.

2. A 2-speed gearbox works as follows. Gear 1 is on a one-way bearing that allows it to rotate freely in a backwards direction but locks it in forward motion. When the power is applied to the car the one-way on the first gear locks to allow the gear to drive the car. At the set RPM the clutch shoes (or finger in the old type gearbox) spread and engage the 2nd gear hub which allows it to take the car to faster speeds (keeping it simple for you). When this happens the one-way bearing in 1st gear disengages and ALLOWS that gear to rotate at the same RPM as the 2nd gear (NOT ROTATE AT A SLOWER RPM WHICH IS IMPOSSIBLE CONSIDERING BOTH GEARS ARE ATTACHED TO A SOLID BELL THAT TURNS BOTH TOGETHER).

You are correct however, a 2-speed gearbox is simple to operate if you know what you are talking about

IMPACTPLAYR

iTrader: (7)

HOLD ON....HOLD ON!!!! I was going from an old 2 speed I used to own a while back, besides NOBODY made any attempt to explain how the 2 speed worked, and when I DID explain all of you wanna jump on and slam me for one little mistake?!?!?! Hello....... I also said the shaft was spinning at a higher RPM and the one-way in gear one disengaged, I never said either gear was spinning faster than the other.....

modellor

Fair enough, you were the only one that attempted to answer how it worked but your explanation was based on false knowledge.

You did mention that when the one-way disengages it allows the 1st gear to rotate at a lower RPM than the shaft which it cannot do.

Also, which car did you own that had 2 one-way bearings in the gearbox running either direction? I have been racing Nitro R/C for 16yrs and never came across this yet. Always been a normal bearing in the second gear hub allowing it to free-wheel in either direction. A reversed one-way in the 2nd hub would effectively make the car a single speed as it would be permanently stuck in second gear.

But to do you justice on this one, someone stated that this would not allow the car to free-wheel at all. This is also an untrue statement. The car would free-wheel once the shoes in the clutchbell disengaged.

IMPACTPLAYR

iTrader: (7)

It was an HPI electric 2-speed....

I must still disagree..... for you see if once the 2nd gear clucth engages and locks the second gear to the shaft, IF the shaft doesn't spin at higher RPM's than the first gear the car will stop accerelating and the 2-speed will totally worthless...... The shaft MUST spin at higher RPM's than the first gear...... now the second spur cannot spin any faster than the the first gear but the shaft that it is driving will....

IMPACTPLAYR

iTrader: (7)

BTW; I knwo it had 2 one way bearings because when I spun 1st gear it would turn the wheels forward, and when I spun 2nd gear backwards it would spin the tires backward..... and because it was my 1st 2speed and was basically a freebee I couldn't resist tearing it apart to see how it works.....LOL

I am an electric racer at heart, but now I am stepping over into my first nitro racecar (NTC3) I have had nitro's before, but never felt the urge to destroy any 2-speeds to see how they worked because I had already done that....LOL

Forgot nitro sedans don't have/need reverse so the second one-way bearing would be useless ...LOL

modellor

Yes, that is correct. I misinterpreted your meaning of the 1st gear turning slower. It doesnt rotate at the exact same speed as the shaft but it does increase in rpm at the same ratio as the second speed gear as both are connected through the clutch bell when the second gear engages. The only difference in speed is the set gearing of the pinions/spur ratio.

However, I would like to see your HPI electric car driving. I still cant picture a gearbox with 2 reversed one-way bearings working as again the 2nd speed gearbox needs to freewheel until it is engaged. The reverse direction one-way would stop this from happening and the 2-speed would be locked in second gear constantly.

Jon Carlson

iTrader: (48)

modellor what I meant by not allowing the car to freewheel is that if there were a oneway bearing in the 2nd gear housing going to opposite direction as the one in the 1st gear housing the shaft would always be held to the gears... the shaft couldn't freespin at all. It wouldn't matter if the clutch was engaged or not. And now it just hit me that he is right. The oneway in the 2nd gear housing would be so that the electric motor could apply brakes to the car. If you think about it for a minute it will come to you. But no Impact that's not how a nitro two speed is. LOL... he did know what he was talking about... in that situation anyway... hehe

Jon