Track keeps falling off sprockets when moving backwards?

If you have a tank query and you can't find the answer anywhere else, post here. (TIP - Check for answers in FAQ, use the 'search' facility or even check this board before posting here).

Postby Haru » Sun Jun 28, 2020 10:39 pm

Currently working on a 1/35 Tamiya JGSDF Type 10 RC tank. Whenever I move the tank backwards, the tracks keep falling out of place from the sprockets. So far, I haven't seen that happen when I move forward. What could be the issue? Thanks

Haru
Recruit
 
Posts: 7
Joined: Mon May 04, 2020 2:29 am

Postby Max-U52 » Sun Jun 28, 2020 10:46 pm

First thing that comes to mind is that your track tension is too loose.
User avatar
Max-U52
Lieutenant
 
Posts: 3770
Joined: Sat Sep 12, 2015 8:56 pm
Location: Detroit

Postby Exhibitedbrute » Sun Jun 28, 2020 11:01 pm

I second that, but track tension is the only thing that comes to my mind

Exhibitedbrute
Sergeant
 
Posts: 551
Joined: Tue Dec 17, 2019 1:27 am

Postby jarndice » Sun Jun 28, 2020 11:46 pm

Forgive me for disagreeing but if the Tank is reversing in a straight line there is no particular reason that track tension or a lack of it would cause the tracks to fall off,
I would look closely at the alignment of the wheels/sprockets/idlers.
I am not familiar with the wheel arrangement of the "Type 10" ,But it would appear that something in the wheel arrangement is driving the tracks off in reverse but not when travelling forward,
As this is written it appears to be happening to both tracks at the same time If it were the track tension I would expect the tracks to fall off in both directions,
My first port of call would be the gearbox output shafts and the gearbox mounting plate and then the sprockets.
User avatar
jarndice
Major
 
Posts: 6039
Joined: Mon Sep 03, 2012 11:27 am
Location: the mountains of hertfordshire

Postby Max-U52 » Mon Jun 29, 2020 12:57 am

jarndice wrote:Forgive me for disagreeing but if the Tank is reversing in a straight line there is no particular reason that track tension or a lack of it would cause the tracks to fall off,
I would look closely at the alignment of the wheels/sprockets/idlers.
I am not familiar with the wheel arrangement of the "Type 10" ,But it would appear that something in the wheel arrangement is driving the tracks off in reverse but not when travelling forward,
As this is written it appears to be happening to both tracks at the same time If it were the track tension I would expect the tracks to fall off in both directions,
My first port of call would be the gearbox output shafts and the gearbox mounting plate and then the sprockets.


That was the second thing that came to mind. @) @) :haha: :haha:
User avatar
Max-U52
Lieutenant
 
Posts: 3770
Joined: Sat Sep 12, 2015 8:56 pm
Location: Detroit

Postby RenoirLV » Mon Jun 29, 2020 6:47 am

From my Tiger experience, I’d say sprocket alignment to the road wheels.


Sent from my iPhone using Tapatalk
User avatar
RenoirLV
Corporal
 
Posts: 254
Joined: Mon Jan 22, 2018 1:58 pm
Location: Riga, Latvia

Postby General Jumbo01 » Mon Jun 29, 2020 11:30 am

Not being familiar with the Type 10 l Googled for an image, only to find a couple of photos of them discarding their tracks in action! So, at least you have a realistic model.

When driving forward the rear sprocket is being fed track from the rearmost road wheel. If all is well going forward then this suggests alignment here is okay. In reverse the sprocket is being fed track from the rearmost return roller. Could it be that these are misaligned?

Generally speaking, in 1/35 scale a lightweight plastic track may benefit from a tighter track tension but only if all wheels and rollers are correctly aligned.

Good luck solving your problem :thumbup:
User avatar
General Jumbo01
Warrant Officer 2nd Class
 
Posts: 1146
Joined: Sat Jul 14, 2018 8:06 pm
Location: I'm a Londoner that moved to Essex. Says it all really...:(

Postby Exhibitedbrute » Mon Jun 29, 2020 4:06 pm

What about a bent gear shaft? That would through the alignment

Exhibitedbrute
Sergeant
 
Posts: 551
Joined: Tue Dec 17, 2019 1:27 am

Postby jarndice » Mon Jun 29, 2020 4:19 pm

jarndice wrote: My first port of call would be the gearbox output shafts and the gearbox mounting plate and then the sprockets.
User avatar
jarndice
Major
 
Posts: 6039
Joined: Mon Sep 03, 2012 11:27 am
Location: the mountains of hertfordshire

Postby Son of a gun-ner » Mon Jun 29, 2020 5:00 pm

What type of tracks does this model have? Are they individual links like our bigger 1/16th tanks, or does it have the continuous rubber type?

I agree that everything should be checked for alignment, I can't help but wonder about the quality of the suspension and road wheel pivot points and bearings. And does this model have any track adjustment capabilities?

When you are driving forward, the suspension arms are trailing, therefore with the sprockets at the rear, the road wheels are being guided when the tracks are being pulled/dragged backwards from under the weight of the tank. This causes some tension from the last road wheel to sprocket, while the tracks are being freely pushed with very little resistance forward across the top on the return rollers (if it has them).
Whereas in reverse, the slack of the track is being pulled backwards and is tightened up across the top on the return rollers, and the sprockets now have that slack under them, as they are trying to push that slack track forward under the load of the tank, which will cause any slack to bunch up around the sprockets making it easier to come off in reverse if something is out of alignment. Even though the tank is effectively being pulled backwards via the idlers from the tightened up track across the return rollers, the track hasn't got the same ease to deal with the slack it had going forward, hence the slack bunching up around the sprocket. As your suspension arms are the trailing type, if you do have play on the wheel bearings and or arm pivots, they will be pushed out of alignment and cause that slack track to come off.
I'm guessing your drive setup in a 1/35th tank is of the single unit type, where apart from turning the whole unit, you have very little adjustment if any at all to adjust the sprocket axle alignment. Can that unit be used to adjust track tension?
User avatar
Son of a gun-ner
TOTM Admin
 
Posts: 3695
Joined: Sun May 07, 2017 8:49 pm
Location: Surrey UK

Postby jimbo_wa » Mon Jun 29, 2020 6:38 pm

Not sure on the Type 10, but on my 1/35th Tamiya Leopard 2 A5 you can adjust the rear sprockets approx. 10mm

Image

No suspension or idler adjustment...

Sent from my Pixel 2 using Tapatalk
User avatar
jimbo_wa
Corporal
 
Posts: 373
Joined: Fri Dec 21, 2018 4:55 pm
Location: Cambridge, UK


Return to General Questions

Who is online

Users browsing this forum: No registered users and 8 guests