RCCrawler Forums

Big Mike · 11-16-2006, 11:29 AM

If you're workin' with the stock TLT transmission, not long after you lock all your differentials you'll notice the next weak link - Belt slippage. The stock setup has no provision for tensioning the belt, so under full torque the belt will jump teeth.
One solution would be one of those trick all metal gearboxes from RC4WD, but since I have spent all my crawler budget for a month or 2, I decided to try to improve the stock TLT transmission by adding my own tensioner.
I scrounged this up and assembled it in about 30 minutes. The only real tricky part was actually spotting the hole in the side of the trans. case for the screw, it's position is critical for the right tension - too close to the belt and it will bind things up, too far away and it will not be effective. Other than that it was simple. Mine ended up right behind the upper link mount, hence the countersunk flathead screw for clearance.

I have not really tested it yet under full-bore condidtions (rain, rain, more rain) but preliminary testing in my indoor facility here has been positive.
Should help out until I can work out another transmission solution...

Mattdg67 · 11-16-2006, 02:43 PM

That looks cool if I can ill try that on my crawler because its still the stock box but yeah your plan sounds great.

jwrape · 11-16-2006, 02:50 PM

Instead of a aluminum roller I would install a bearing

Big Mike · 11-17-2006, 06:32 AM

Absolutely, a bearing would definitely be superior.
I just scrounged this up as a temporary fix, but I could'nt find a bearing or bushing small enough for this application in my hoard of junk.
I know it won't last forever, but it will get me to my next transmission.

Big Mike · 11-18-2006, 01:58 PM

Well, the tensioner idea certainly took a lot of play out of the belt, but it still slips under hard torque in real crawling conditions. I set the tension so you can't really deflect the belt by pushing on it, it's pretty tight - but it still slips. I'm pretty sure it's not the differential slipping, I did just bolt it together w/ no bearings, but I could not get it to slip when I tested it before re-assembling.
That would be the next logical step, slugbugg - physically holding the belt against the pulleys might keep the teeth engaged, but you'd need one for each pulley. And spotting the "axles" for them to run on in the right spots would be next to impossible.
At this point my opinion is that the stock TLT trans might work fine for a 1:18th scale toy, but for serious crawling it is sorely lacking.
I give up. I guess I'm gonna have to rework this thing again with a different transmission.

beaglegod · 11-20-2006, 11:50 PM

Looking at the stock belt its a bit flimsy, perhaps as was suggested by austincrawls a better belt would help.

http://www2.towerhobbies.com/cgi-bin...?&I=LXM740&P=7

Its a direct fit a wee bit wider but also thicker and the teeth seem more pronounced at least from the photos it looks like a better quality belt.

Big Mike · 11-22-2006, 07:08 AM

Allright, it was actually the differential slipping, not the belt. The belt tensioner did work, well enough to work loose my mechanical diff lock. Now I've locked it with pool putty epoxy, this stuff dries hard as a rock. Should be good to go now.
There is room on the pulleys for a slightly wider belt. Maybe as much as 1/16th wider. Hmmmm...
Test run this afternoon, gettin' off early...

Big Mike · 11-22-2006, 12:54 PM

Geez, more rain!! Damn!
Oh well, a little indoor testing has shown zero belt slipping now. It even "feels" like I have more torque than before.
I did also swap in a 3-channel reciever today (Ind. 4WS is far superior to a y-harness) but I don't see how that would affect the motor. Still the same speed control.
Man, I wish it would stop raining...

wampir · 12-05-2006, 09:00 PM

Has it stopped raining yet, do you have any pics of the actual implemented fix? This is very interesting as my rc budget has effectivly dried up (or should I say re-prioritized by my wife) and anything to use existing parts is a huge plus.

DUIdirk · 12-05-2006, 09:18 PM

sounds like a wonderfull plan

Big Mike · 12-06-2006, 07:15 AM

Yea, it stopped raining. But it has been colder than usual. Anyway, the middle differential is locked solid now, and the belt tensioner is definitely improving performance. The belt has not slipped once since I put it back together the second time.

Sorry, no digi pics from me for a bit. My cam is on the fritz and I can't afford a new one just yet. I need to get another one so I can show off the new 73 Bronco body and RC4WD beadlocks I just got last week.
My TLT is drifting out of the realm of "low-buck". The urge to upgrade is just too strong to resist...

gotmuddy · 12-06-2006, 08:42 AM

The rc4wd tranny is well worth the $$$. I love mine, its super pimp.

It only took one outing with my belt drive to hate its guts.

Big Mike · 12-06-2006, 10:19 AM

Once I free up the funds for one of those R2's, and a pair of Punisher shafts, my TLT will be pretty much done. I'm happy with everything else (for now, anyway)
With all the nice tube chassis everyone is fabricating on here, I'm sure I'll want to tackle one of those eventually...

Matty_C · 12-07-2006, 05:03 AM

hey i have done this mod to my tlt trans and it helped alot but i trashed the teeth on the belt so i went to the lhs and got a hobao drive belt the part # is 224061 it is a proper belt very strong and it is fiberglass reinforced great buy at $13AUD cant go rong.

gotmuddy · 12-07-2006, 08:15 AM

Them punisher shafts are super nice, but t-maxx shafts work fine.

tjarr001 · 03-06-2007, 01:27 PM

so have you been able to get a pic of that belt tensioner yet?

SnailMail · 03-06-2007, 06:52 PM

i attacked my dif with hot glue, then JB weld epoxy, and the belt has yet to stretch, and skip, buit the diff is holding up, just to let you know, so you can do it to yours, but try a berring, it rotates much smother, try enco for berings of all sizes

Big Mike · 03-07-2007, 06:58 AM

Since I saw this old thread bumped up, I'll throw out a little update.
I tried one of those HPI belts (S3M 180 5.5mm) and although it is definitely a wider, thicker belt, it's also just a tenth or 2 bigger in diameter. It skipped way worse than the stock belt.
I need to install a real bearing in the tensioner anyway, so apparently I've got room for something a little bigger than the roller I have now. The HPI belt would definitely be a better option w/ more tension on it.
I can do a pic w/ my Treo and post it, but it won't be the best quality. It should get the point across though. I don't want to disassemble half my rig just to take pics either, but when it happens I'll get some...

tjarr001 · 03-07-2007, 08:21 AM

i just got an idea to try out. what if you used a servo saver, like the one that comes in the tlt kit, and screved it to the insid of the tranny case, then crewed that tensioner that big mike made to the servo saver and made it to where it acted like a belt tensioner on a car. tighten the servosaver down and swist it up, then put the belt under it so when the saver tried to go back to normal position it would put tension on the belt.

gr33nlemon · 03-07-2007, 10:22 AM

Quote:

Originally Posted by tjarr001

i just got an idea to try out. what if you used a servo saver, like the one that comes in the tlt kit, and screved it to the insid of the tranny case, then crewed that tensioner that big mike made to the servo saver and made it to where it acted like a belt tensioner on a car. tighten the servosaver down and swist it up, then put the belt under it so when the saver tried to go back to normal position it would put tension on the belt.

That sounds like a pretty good idea, but I wonder how much the servo saver would move around under a high-load situation. Maybe I'll have to give that a shot when I get around to messing with the tranny.

11-16-2006, 11:29 AM	#1
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	low-buck TLT... If you're workin' with the stock TLT transmission, not long after you lock all your differentials you'll notice the next weak link - Belt slippage. The stock setup has no provision for tensioning the belt, so under full torque the belt will jump teeth. One solution would be one of those trick all metal gearboxes from RC4WD, but since I have spent all my crawler budget for a month or 2, I decided to try to improve the stock TLT transmission by adding my own tensioner. I scrounged this up and assembled it in about 30 minutes. The only real tricky part was actually spotting the hole in the side of the trans. case for the screw, it's position is critical for the right tension - too close to the belt and it will bind things up, too far away and it will not be effective. Other than that it was simple. Mine ended up right behind the upper link mount, hence the countersunk flathead screw for clearance. I have not really tested it yet under full-bore condidtions (rain, rain, more rain) but preliminary testing in my indoor facility here has been positive. Should help out until I can work out another transmission solution...

11-18-2006, 01:58 PM	#5
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Well, the tensioner idea certainly took a lot of play out of the belt, but it still slips under hard torque in real crawling conditions. I set the tension so you can't really deflect the belt by pushing on it, it's pretty tight - but it still slips. I'm pretty sure it's not the differential slipping, I did just bolt it together w/ no bearings, but I could not get it to slip when I tested it before re-assembling. That would be the next logical step, slugbugg - physically holding the belt against the pulleys might keep the teeth engaged, but you'd need one for each pulley. And spotting the "axles" for them to run on in the right spots would be next to impossible. At this point my opinion is that the stock TLT trans might work fine for a 1:18th scale toy, but for serious crawling it is sorely lacking. I give up. I guess I'm gonna have to rework this thing again with a different transmission. Last edited by Big Mike; 11-18-2006 at 02:01 PM.

11-22-2006, 07:08 AM	#7
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Allright, it was actually the differential slipping, not the belt. The belt tensioner did work, well enough to work loose my mechanical diff lock. Now I've locked it with pool putty epoxy, this stuff dries hard as a rock. Should be good to go now. There is room on the pulleys for a slightly wider belt. Maybe as much as 1/16th wider. Hmmmm... Test run this afternoon, gettin' off early... Last edited by Big Mike; 11-22-2006 at 07:11 AM.

03-07-2007, 06:58 AM	#18
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Since I saw this old thread bumped up, I'll throw out a little update. I tried one of those HPI belts (S3M 180 5.5mm) and although it is definitely a wider, thicker belt, it's also just a tenth or 2 bigger in diameter. It skipped way worse than the stock belt. I need to install a real bearing in the tensioner anyway, so apparently I've got room for something a little bigger than the roller I have now. The HPI belt would definitely be a better option w/ more tension on it. I can do a pic w/ my Treo and post it, but it won't be the best quality. It should get the point across though. I don't want to disassemble half my rig just to take pics either, but when it happens I'll get some... Last edited by Big Mike; 03-07-2007 at 07:00 AM.

11-16-2006, 02:43 PM	#2
Mattdg67 Rock Stacker Join Date: Apr 2006 Location: North Providence Posts: 78	That looks cool if I can ill try that on my crawler because its still the stock box but yeah your plan sounds great.

11-16-2006, 02:50 PM	#3
jwrape Rock Crawler Join Date: Jan 2005 Location: Bethlehem, GA Posts: 583	Instead of a aluminum roller I would install a bearing

11-17-2006, 06:32 AM	#4
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Absolutely, a bearing would definitely be superior. I just scrounged this up as a temporary fix, but I could'nt find a bearing or bushing small enough for this application in my hoard of junk. I know it won't last forever, but it will get me to my next transmission.

11-20-2006, 11:50 PM	#6
beaglegod Newbie Join Date: Nov 2006 Location: United States Posts: 7	Looking at the stock belt its a bit flimsy, perhaps as was suggested by austincrawls a better belt would help. http://www2.towerhobbies.com/cgi-bin...?&I=LXM740&P=7 Its a direct fit a wee bit wider but also thicker and the teeth seem more pronounced at least from the photos it looks like a better quality belt.

11-22-2006, 12:54 PM	#8
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Geez, more rain!! Damn! Oh well, a little indoor testing has shown zero belt slipping now. It even "feels" like I have more torque than before. I did also swap in a 3-channel reciever today (Ind. 4WS is far superior to a y-harness) but I don't see how that would affect the motor. Still the same speed control. Man, I wish it would stop raining...

12-05-2006, 09:00 PM	#9
wampir Newbie Join Date: Sep 2006 Location: Charlottesville Posts: 11	Has it stopped raining yet, do you have any pics of the actual implemented fix? This is very interesting as my rc budget has effectivly dried up (or should I say re-prioritized by my wife) and anything to use existing parts is a huge plus.

12-05-2006, 09:18 PM	#10
DUIdirk Pebble Pounder Join Date: Sep 2005 Location: Bellevue Posts: 122	sounds like a wonderfull plan

12-06-2006, 07:15 AM	#11
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Yea, it stopped raining. But it has been colder than usual. Anyway, the middle differential is locked solid now, and the belt tensioner is definitely improving performance. The belt has not slipped once since I put it back together the second time. Sorry, no digi pics from me for a bit. My cam is on the fritz and I can't afford a new one just yet. I need to get another one so I can show off the new 73 Bronco body and RC4WD beadlocks I just got last week. My TLT is drifting out of the realm of "low-buck". The urge to upgrade is just too strong to resist...

12-06-2006, 08:42 AM	#12
gotmuddy Pebble Pounder Join Date: Nov 2005 Location: N. Arkansas Posts: 143	The rc4wd tranny is well worth the $$$. I love mine, its super pimp. It only took one outing with my belt drive to hate its guts.

12-06-2006, 10:19 AM	#13
Big Mike I wanna be Dave Join Date: Oct 2006 Location: Martinsburg WV Posts: 2,781	Once I free up the funds for one of those R2's, and a pair of Punisher shafts, my TLT will be pretty much done. I'm happy with everything else (for now, anyway) With all the nice tube chassis everyone is fabricating on here, I'm sure I'll want to tackle one of those eventually...

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12-07-2006, 05:03 AM	#14
Matty_C Newbie Join Date: Oct 2006 Location: Adelaide,Australia Posts: 19	hey i have done this mod to my tlt trans and it helped alot but i trashed the teeth on the belt so i went to the lhs and got a hobao drive belt the part # is 224061 it is a proper belt very strong and it is fiberglass reinforced great buy at $13AUD cant go rong.

12-07-2006, 08:15 AM	#15
gotmuddy Pebble Pounder Join Date: Nov 2005 Location: N. Arkansas Posts: 143	Them punisher shafts are super nice, but t-maxx shafts work fine.

03-06-2007, 01:27 PM	#16
tjarr001 Rock Stacker Join Date: Feb 2007 Location: jacksonville Posts: 90	so have you been able to get a pic of that belt tensioner yet?

03-06-2007, 06:52 PM	#17
SnailMail Quarry Creeper Join Date: Jan 2007 Location: New York Posts: 260	i attacked my dif with hot glue, then JB weld epoxy, and the belt has yet to stretch, and skip, buit the diff is holding up, just to let you know, so you can do it to yours, but try a berring, it rotates much smother, try enco for berings of all sizes

03-07-2007, 08:21 AM	#19
tjarr001 Rock Stacker Join Date: Feb 2007 Location: jacksonville Posts: 90	i just got an idea to try out. what if you used a servo saver, like the one that comes in the tlt kit, and screved it to the insid of the tranny case, then crewed that tensioner that big mike made to the servo saver and made it to where it acted like a belt tensioner on a car. tighten the servosaver down and swist it up, then put the belt under it so when the saver tried to go back to normal position it would put tension on the belt.

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