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O.S. .18 TM Question

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daculatruck50

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I just got an O.S. .18 tm for my pro .15 t-maxx. I bought the upgrade kit and I have it installed and running but I cannot get the clutch bell and spur gear to mesh. The Os has the 15 tooth revo clutch bell on it and the transmission has the original .15 spur gear. Will these mesh or no? If so can you explain to me the proper technique. I have done it before and have had no problems I don't know what it Is. I figure the teeth don't match up or something. What could be wrong? Thanks.
 
I am no expert, but I can tell you it probably has zero to do with the number of teeth and everything to do with the pitch of the gears not being the same.

This explains it, but is really technical: http://www.abslotsport.com/page8.html This is for slot cars in particular but the science applies to RC.

And as always, I could be wrong.
 
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So do you have any recommendations for what could fix my gear mesh problems? Bigger clutch bell?
 
The number of teeth is not your issue IMO, so a bigger bell would not solve the problem. It is about the angle of the teeth in the gears not being the same. I can not explain it any better. Maybe some of the more technically savvy guys will pop in later to explain.
 
If I were you I would use the bell gear that came with the .15 engine. The Revo (as far as I know) has always used a different pitch bell and spur gear than the T-Maxx until the newer 3.3 was released with the Revo spec stuff. So will not be compatible as was said above by RC Addict. Any bell gear for a 2.5 T-Maxx (should) work for you such as the 4116, 4118 Traxxas part numbers.
 
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Yeah, the t-maxx pro15 and 2.5 all ran 32P spur gears whereas the revo runs 1M pitch (same as almost all 1/8 scale stuff). Oddly enough, traxxas decided .8M pitch was to be used on the jato... don't really understand that one.

You need to get a 32P CB to run with your spur. Since your running a 18TM, you can gear it higher than with the 15. The 18TM will have the power to pull it without issue.

The old 2.5 maxx came with a 20T bell, but I'd think the 18TM would pull a 22T bell just fine. I not sure what bell you currently have, but the 20T and 22T require 5x11 bearings vs the more standard 5x10. If you have an 18T traxxas bell currently (from the pro15), it's using the 5x10 bearings.


I'd suggest at this time that you put all 12 friction pegs in the spur, if you already haven't. This will help you avoid melting spurs in the near future with the extra power of the 18TM. The older t-maxx's came with 6 pegs. Not really sure why as having 12 just let you set your slipper properly without having to worry so much about it melting down.
 
Well you still rock in my book! Congrats on going blue. It is well deserved and looks very good on you. I am envious to be sure!

BTW--Can I call you Bryan now? LMAO!
 
Thank y'all for the help. All of that makes perfect sense now. I put my old 18 tooth pro .15 clutch bell on there and it meshes perfectly. I took it out to run it and I now have another problem. My clutch bell spins freely very fast at idle causeing my spur gear to spin really fast to because there are now meshed. When I hit the gas my truck doesn't go anywhere. The engine revs but doesn't move. I'm guessing maybe a worm out clutch spring maybe?
 
the spur gear moves as well as the clutch bell? at idle and when you mash the gas? if so, you either have a stripped tranny gear, you're slipper clutch isn't tight enough, or you broke one of your output yokes , possibly broke a pin in the hexes for the wheels... all this needs to be checked, leave the gears for last.

i'd really like to know how this runs for you, i have the same exact setup but i never drilled the holes in the chassis for the throttle linkage, my motoer/ez start etc. has never been ran.
 
Yes. I got the truck running good when all the sudden I cranked it up and I noticed the clutch bell was spinning freely (as fast as the engine was idleing. This turned the spur gear just as fast. The more gas I gave it the faster they would both spin but no movement.
 
that could be about 100 things as i stated above, that spur gear inside the tranmissision prob. has a pin in it as well. like i said above, check to see if your driveshafts spin when the spur spins, spin it with your hand, you don't have to have it started, spin the spur freely with your hand and see if it feels like it's spinning any other gears in the tranny..if your driveshafts are not spinning look closer and see if it looks like the outputs are spinning. you could have snapped a output i just snapped one on a brushless traxxas slash. if you still can't figure it out, you'll prob. have to take the tranmission apart and see where it stops spinning.
 
I was thinking. My clutch bell constantly spins even when the engine is idleing. Luke the clutch pads are constantly engaged. Could it be the spring or is it just that there is no resistance because I broke the tranny somewhere?
 
the clutchbell always spinning "the tires should always spin" if it's a bad clutch spring, since the spur is freely spinning, something else is wrong somewhere, i dunno where. you could have a bad clutch spring as well, but that's not why it's not moving, it should move. if the spur is moving, unless you have something wrong with the tranny, output shafts, slipper clutch, or pins for wheels etc...



actually, i take back everything i jsut said, iw as thinking we were talking about a stampede. something is wrong with your tranny. possibly the clutch. inside the tranny. it's hard to tell what it is, the t-maxx .15's have 2 clutches, the clutch on the motor and the clutch in the tranny, try unplugging your reverse servo and manually move it all the way forward then rev it up, see if it moves, then move it all the way in reverse and see if it moves.
 
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x_doug_x said:
the t-maxx .15's have 2 clutches, the clutch on the motor and the clutch in the tranny, try unplugging your reverse servo and manually move it all the way forward then rev it up, see if it moves, then move it all the way in reverse and see if it moves.
Click to expand...

I'd try switching the trans between forward/reverse via the remote and see if your linkage moves. As suggested, you may be stuck between gears.

Most people ditched reverse and installed a forward only conversion since reverse was so weak and tended to strip out on you. The FOC gear was twice as wide as the stock gear, so it held up much longer.

It also removes a bunch of dead weight out of the trans and makes the free spinning spur go away, which then makes take off much more smooth.
 

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