tamiya servo saver discussion

[twaleta]

Tamiya has servo savers in almost all of there kits but i always wonder,why are they designed like that?They are very sloppy even with a high torque servo saver.But i also have a traxxas slash and the servo saver on that has a spring inside,i didnt even tell it was a servo saver because it felt like i had a servo horn on it.The traxxas spring servo saver is superior to the tamiya metal clip thingy one why does tamiya not change there design?

[Pylon80]

I am not sure what you mean by sloppy? Does yours have play?

The basic kits do come with all-plastic servo savers that will protect the servo from the hard impacts you would expect from a beginner driving that basic kit, but unfortunately they usually do not center very well.

The higher end kit come with a high torque servo saver; this one works very well with perfect centering (I have 4 of them on my very small fleet). In fact, the high torque servo saver is actually so stiff that I usually remove one of the two smaller inner springs. The result is stiff enough for 1/10 scale use. Anything stiffer and I  feel that I might as well use a solid horn.

[alvinlwh]

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[twaleta]

11 minutes ago, Pylon80 said:

I am not sure what you mean by sloppy? Does yours have play?

The basic kits do come with all-plastic servo savers that will protect the servo from the hard impacts you would expect from a beginner driving that basic kit, but unfortunately they usually do not center very well.

The higher end kit come with a high torque servo saver; this one works very well with perfect centering (I have 4 of them on my very small fleet). In fact, the high torque servo saver is actually so stiff that I usually remove one of the two smaller inner springs. The result is stiff enough for 1/10 scale use. Anything stiffer and I  feel that I might as well use a solid horn.

it cant drive straight at high speed either and after 1 run the servo saver was like seperating 

[twaleta]

46 minutes ago, alvinlwh said:

It is not just the servo saver but all parts of the steering components are sloppy, especially in the lower price end cars like the TT and M-05/6 (for example*). The list of official hopups required to sort out the steering problems on these cars is long and eye wateringly expensive. Third party parts are usually cheaper, and usually come as a complete solution instead of different little bits and pieces.

I believe Tamiya intend these chassis as "starter" kits and have plenty of allowance for beginners and, like bearings (for example), another revenue stream for them. However the poor steering (overall, not just servo saver) makes the experience disappointing for a beginner.

*I only have experience with their < £200 kits so cannot comment on their higher end offerings. However, both in terms of quality and bang for buck, the 3R, MST and LRP kits I have are much better in all aspects, not just servo saver.

I agree that higher prices give you better quality most of the time.But i have seen many videos and stuff on people running/racing tt02s and they mostly have horns or aftermarket servo savers.They drive straight and are more controlled

 

(edit: its probably not the servo saver then its because i chose a to short screw)

[Pylon80]

I don't think your problems are related to the servo saver itself. If you use a metal gear servo then you will need to use a small drop of loctite to prevent the screw from loosening. The HT servo saver usually comes with multiple types of screws to fit your servo so if you use one of these the length will be right 👍

[twaleta]

2 minutes ago, Pylon80 said:

I don't think your problems are related to the servo saver itself. If you use a metal gear servo then you will need to use a small drop of loctite to prevent the screw from loosening. The HT servo saver usually comes with multiple types of screws to fit your servo so if you use one of these the length will be right 👍

i used the screw that came with the savox servo,it was kinda short.Do you think thats the problem?

[Willy iine]

Yeah, you need to use a longer screw. It's just a M3.. try a 8-10mm length if you have one.

Most (if not all) my Tamiya's run their high torque servo savers.  They work fine.    

I've heard some people complain about re-centering when they used those blue aluminum horns on their high torque servo savers.. if you're using one of those aluminum horns, try the factory plastic one that comes with the high torque servo saver set.

[twaleta]

14 minutes ago, Willy iine said:

Yeah, you need to use a longer screw. It's just a M3.. try a 8-10mm length if you have one.

Most (if not all) my Tamiya's run their high torque servo savers.  They work fine.    

I've heard some people complain about re-centering when they used those blue aluminum horns on their high torque servo savers.. if you're using one of those aluminum horns, try the factory plastic one that comes with the high torque servo saver set.

ill try to find the screw then compare aluminium vs stock and see if theres a improvement.I cant believe one screw could cause change xd

[Willy iine]

13 minutes ago, twaleta said:

ill try to find the screw then compare aluminium vs stock and see if theres a improvement.I cant believe one screw could cause change xd

Yeah, Amazon sells a small box set of M2 and M3 screws if you're interested.  They're like $12 and comes with a bunch of different lengths. Very useful for when you need that one particular screw.. they sell washers too.

I use a lot of the generic M2/M3 sizes for my stryene builds...

[Pylon80]

2 hours ago, twaleta said:

i used the screw that came with the savox servo,it was kinda short.Do you think thats the problem?

I do.

[Pylon80]

Another thing to look out for @twaleta is the number of splines on the servo saver lower part. It comes with two (I think) a 24 and a 25 splines. Savöx uses 25. Apologies if I state the obvious but I made the mistake once when I switched from Futaba to Hitec! When you make that mistake, the servo saver might seem like it fits but then it will keep sliding around the final drive gear and the car will seem like it's randomly pulling left or right.

[Mad Ax]

I think Tamiya servo savers were designed back when everyone was using servos with plastic gears.  Then you'd have a self-tapping screw into the top of the servo, so it would stay in place even when the screw isn't fully tightened down, which is necessary to allow the servo saver to move and recentre.

Many modern servos have metal splines, therefore a machine screw is needed.  When this is torqued down enough to stay in place, it's also tight enough to prevent the servo saver from moving.  This causes it to go off-centre and need constant retrimming.

The solutions are:

a) make sure you have installed the little plastic circular washer when you assemble the servo saver, as this gives some space for the servo saver to move when torqued down (it doesn't seem to work if a metal washer is substituted, maybe because metal washers are slightly dished and bind on the plastic parts)

b) use some threadlock and don't overtighten the screw, before installing the servo make sure you can stretch the servo saver in both directions and it will freely turn back to the centre position without any help

Although if you're racing or running hard, you'll probably want a stronger servo saver - the Tamiya design is pretty old and doesn't really compete with modern manufacturer designs

[El Gecko]

I added a metal spring to mine, works much better now. Also using machine screws in my metal gear servos with no problems. It just took a lot of trial and error in the beginning to find a set of washers/spacers that fit exactly right without binding. But the new spring really helps it stay centered and accurate.

[Willy iine]

1 hour ago, Mad Ax said:

I think Tamiya servo savers were designed back when everyone was using servos with plastic gears.  Then you'd have a self-tapping screw into the top of the servo, so it would stay in place even when the screw isn't fully tightened down, which is necessary to allow the servo saver to move and recentre.

Many modern servos have metal splines, therefore a machine screw is needed.  When this is torqued down enough to stay in place, it's also tight enough to prevent the servo saver from moving.  This causes it to go off-centre and need constant retrimming.

The solutions are:

a) make sure you have installed the little plastic circular washer when you assemble the servo saver, as this gives some space for the servo saver to move when torqued down (it doesn't seem to work if a metal washer is substituted, maybe because metal washers are slightly dished and bind on the plastic parts)

b) use some threadlock and don't overtighten the screw, before installing the servo make sure you can stretch the servo saver in both directions and it will freely turn back to the centre position without any help

Although if you're racing or running hard, you'll probably want a stronger servo saver - the Tamiya design is pretty old and doesn't really compete with modern manufacturer designs

Very important indeed.  

[Pylon80]

2 hours ago, Mad Ax said:

b) use some threadlock and don't overtighten the screw, before installing the servo make sure you can stretch the servo saver in both directions and it will freely turn back to the centre position without any help

I would also add that threadlocker can take a considerable amount of time to set (to swell actually) so one needs to wait overnight before trying to stretch the servo saver as described by @Mad Ax 👍

[Pablo68]

Almost all Tamiya servo savers are TRASH and should be replaced with aftermarket ones. I go for the Kimborough medium servo saver on as many of my Tamiya cars as I can. Actually the hi torque Tamiya ones are ok.

[Mad Ax]

2 hours ago, El Gecko said:

I added a metal spring to mine, works much better now

I put a ziptie around mine and pull it as tight as I can

[twaleta]

15 hours ago, Pylon80 said:

Another thing to look out for @twaleta is the number of splines on the servo saver lower part. It comes with two (I think) a 24 and a 25 splines. Savöx uses 25. Apologies if I state the obvious but I made the mistake once when I switched from Futaba to Hitec! When you make that mistake, the servo saver might seem like it fits but then it will keep sliding around the final drive gear and the car will seem like it's randomly pulling left or right.

yeah i think the tamiya one fits on the savox,ill try a longer screw and see if its not going crazy and drives good

[Sogogi]

18 hours ago, Pylon80 said:

Another thing to look out for @twaleta is the number of splines on the servo saver lower part. It comes with two (I think) a 24 and a 25 splines. Savöx uses 25. Apologies if I state the obvious but I made the mistake once when I switched from Futaba to Hitec! When you make that mistake, the servo saver might seem like it fits but then it will keep sliding around the final drive gear and the car will seem like it's randomly pulling left or right.

This x100.

Now newer hitec servos come with 25t, but not having 24t adapter really sucks  

[Pylon80]

15 minutes ago, Sogogi said:

This x100.

Now newer hitec servos come with 25t, but not having 24t adapter really sucks  

The beauty of the Tamiya ones is that they come with both 😎

[twaleta]

still when in high speed the wheels wiggle,i either need a better servo saver with a spring in it or a servo horn 

[Willy iine]

3 minutes ago, twaleta said:

still when in high speed the wheels wiggle,i either need a better servo saver with a spring in it or a servo horn 

Are you saying you are allowing the wheels to free wheel with you throttling all the way?   I know some folks like doing this, but it really takes the drivetrain beyond its capabilities while running a hot motor.. I recommend against doing this if you are.

Also your steering linkage might be the root cause, also your wheel/tires might be out of balance or not true..   Not sure, but at this point, I doubt that it is the high torque servo saver if you are running the correct length screw for the horn..

[El Gecko]

7 hours ago, Mad Ax said:

I put a ziptie around mine and pull it as tight as I can

Yep I tried that with various thicknesses of zipties, and none held. They didn't allow any stretch/flex in the servo saver, and would end up loose or broken after the first run because they weren't allowing the saver to do its job. But the metal spring allows everything to rotate and flex like normal, it just takes more force to flex it out than with only the puny plastic "spring" that comes on the sprue. And it's a more solid snap back into its neutral resting place, so it stays centered like it's supposed to. It really transformed the handling of my DT02 and Hornet.

[El Gecko]

54 minutes ago, twaleta said:

still when in high speed the wheels wiggle,i either need a better servo saver with a spring in it or a servo horn 

Hmm I've seen front wheels wiggling with the wrong gyro settings or as Willy says, loose linkages or imbalanced wheels/tires.

If you get a different (stronger) servo saver and it's still wiggling, there might also be something weird with the driveshafts or diff settings.