Kagama Lee Spring Servo Saver Spring - What you need to know

[Nelson.81]

I'm very curious as to what methodology you're all using to set your server savers so that they still "save".

I clamp the front wheels in workmate bench and articulate the servo, and keep tightening right to the point just before where it looks like it's locked and then back off an 8th. Can be a laborious process, but I want maximum steering with minimum loss of "save"

I hold the servo horn by hand then I turn the wheel against it by hand also and you can see & feel how much load it takes to split the servo saver set it as tight or loose as want it. So if you hit your wheel in a bump the kind of impact that would put the servo saver you want it to split & save the servo but still be tight enough so the load put on it when steering isn’t enough to split it so still have positive steering feel. It’s just getting the balance between the two

 

[danl]

I also hold the servo horn and try to move the tires.

One thing I noticed is on my Kagama LE, it has one half of the servo saver in aluminum. Unfortunately this part gets chewed up and starts digging into the plastic piece, effectively locking the servo saver up. So I moved over to plastic upper and lower on that vehicle to match my Spark and I like it. I also put the plastic steering end links on the kagama, to provide some flexibility to hopefully protect the servo as well. It all seems to be working out quite well.

 

[Nelson.81]

I also hold the servo horn and try to move the tires.

One thing I noticed is on my Kagama LE, it has one half of the servo saver in aluminum. Unfortunately this part gets chewed up and starts digging into the plastic piece, effectively locking the servo saver up. So I moved over to plastic upper and lower on that vehicle to match my Spark and I like it. I also put the plastic steering end links on the kagama, to provide some flexibility to hopefully protect the servo as well. It all seems to be working out quite well.

You can get the other half in 7075 also.

 

[Atomic Skull]

I'm very curious as to what methodology you're all using to set your server savers so that they still "save".

I clamp the front wheels in workmate bench and articulate the servo, and keep tightening right to the point just before where it looks like it's locked and then back off an 8th. Can be a laborious process, but I want maximum steering with minimum loss of "save"

I set it up like the picture Horatio posted. As I said I had no problems with the SCT tires it was when I installed the Tomahawk SGT low profile tires that the problems started. Also should be mentioned that I have a Mamba Monster X 8S ESC and a Castle 1717 motor in it which is actually a 1/6 scale power system. EDIT: I am currently using a 7075 aluminum servo saver arm not the stock plastic one in the picture.

EDIT: Also the Ypin steering servo has proven to be very good it survived the bent servo arm and torn out link with no damage. Though you need to modify the servo mount to get it to fit in a Corally vehicle as detailed here: https://www.corallyforum.com/thread...-4-uk-cheaper-but-good.1518/page-2#post-22128

Also I am currently using the 55kg-cm GX3255BLS not the 70kg-cm version because I bricked it trying out various TTL USB programming dongles trying to get the programming software to work without buying the Ypin dongle, which was stupid I guess. I feel the slightly weaker slightly faster version is better for a 1/8 scale car anyway.

 

[danl]

You can get the other half in 7075 also.

I would be afraid of metal to metal galling with no lubrication. Plus plastic is strong enough for me. If it breaks, which it never has, it’s just a backup servo saver.

 

[danl]

Also I am currently using the 55kg-cm GX3255BLS not the 70kg-cm version because I bricked it trying out various TTL USB programming dongles trying to get the programming software to work without buying the Ypin dongle, which was stupid I guess. I feel the slightly weaker slightly faster version is better for a 1/8 scale car anyway.

I am using the same servo on my kagama 6s and like it a lot. It has enough torque to over power the lee spring, so the higher tq model won’t help. The higher speed is noticeable over my spark, which uses a corally COR52015 servo. Both vehicles use a Lee spring.

 

[Horatio]

I would be afraid of metal to metal galling with no lubrication. Plus plastic is strong enough for me. If it breaks, which it never has, it’s just a backup servo saver.

I quite agree. This is an area that doesn't require any unnecessary extra weight. Composite nylon material seems ideally suited for the cam operated servo saver application, but obviously 7075 would be prettier.

 

[Atomic Skull]

I also hold the servo horn and try to move the tires.

One thing I noticed is on my Kagama LE, it has one half of the servo saver in aluminum. Unfortunately this part gets chewed up and starts digging into the plastic piece, effectively locking the servo saver up. So I moved over to plastic upper and lower on that vehicle to match my Spark and I like it. I also put the plastic steering end links on the kagama, to provide some flexibility to hopefully protect the servo as well. It all seems to be working out quite well.

If it's getting chewed up by plastic then it's definitely not 7075, I doubt it's even 6061. I could see the plastic side getting chewed up but not aluminum. I have the 7075 ADU racing one and I have had no problems with it.

 

[Atomic Skull]

I would be afraid of metal to metal galling with no lubrication. Plus plastic is strong enough for me. If it breaks, which it never has, it’s just a backup servo saver.

Yes aluminum on aluminum is a big no-no you would need a bearing surface to prevent galling either steel, brass, PTFE or POM. An aluminum lower half would in theory not flex under high loads but idk if that's even a problem that happens in normal use.

If I were to design one what I would do is have a flexible floating PTFE or HDPE washer sandwiched between the upper and lower half of the servo saver that gets pressed together by the two haves to conform it into shape.

 

[Atomic Skull]

I am using the same servo on my kagama 6s and like it a lot. It has enough torque to over power the lee spring, so the higher tq model won’t help. The higher speed is noticeable over my spark, which uses a corally COR52015 servo. Both vehicles use a Lee spring.

Did you modify the servo mount? When I went to install one on my Asuga I couldn't get the wire in without possibly damaging it so I modified the mount so it could be fit in from the side. this also has the side benefit of allowing airflow around the servo body for better cooling.

 

[danl]

It’s been a bit since I fitted the servo, but I believe I made a channel with a dremel to allow the wire clearance when sliding the servo in. I did not cut it like yours. I did have to space it up with two washers under the mounting ears, so that it did not contact the chassis.

I believe my servo saver got sand in it and with the loose factory spring it was activating constantly. It essentially galled the aluminum and it had too much friction, effectively locking it to the plastic other half. The full plastic servo saver doesn’t activate as much with the Lee spring, so it’s already outlasted the stock LE setup. I’ve broken tie rods, suspension arms, and cvd’s but not the plastic servo saver.

 

[danl]

As they say, a picture is worth a word or two....

Hopefully it is clear to see, the servo saver is not happy.

Remove some material in the area below to allow clearance to slide the servo power wire in. This part is not modified, but the one in the car I just used a Dremel sanding drum.

 

[Atomic Skull]

Remove some material in the area below to allow clearance to slide the servo power wire in. This part is not modified, but the one in the car I just used a Dremel sanding drum.
View attachment 10508

How I would do that is stick a grinding disk in a drill press and then clamp the servo saver square with the table and line the drill head and disk up with one side of the original slot and lengthen it, then the other side of the slot and repeat to finish it. That's how I cut the side of the servo mount except I used a cutting wheel to slice a section of it out instead.

 

[Nelson.81]

Finally pulled the front off the Kronos & threw one these AliExpress springs in the servo saver. Squared it off with a grinder 1st fits no problems & a lot easier than the too narrow hpi hard spring. It’s stiffer than stock & still offers servo saver action so unless the spring snaps don’t see there being any issues with it. Trying the stainless steel version it feels strong enough but if not can always try the slightly stiffer Mn65 spring. Maybe get it out for a test run tomorrow.

 

[Horatio]

Finally pulled the front off the Kronos & threw one these AliExpress springs in the servo saver. Squared it off with a grinder 1st fits no problems & a lot easier than the too narrow hpi hard spring. It’s stiffer than stock & still offers servo saver action so unless the spring snaps don’t see there being any issues with it. Trying the stainless steel version it feels strong enough but if not can always try the slightly stiffer Mn65 spring. Maybe get it out for a test run tomorrow.

View attachment 10646

View attachment 10647

View attachment 10648

View attachment 10649

View attachment 10650

Cheers for taking the time to try these.

 

[Atomic Skull]

Finally pulled the front off the Kronos & threw one these AliExpress springs in the servo saver. Squared it off with a grinder 1st fits no problems & a lot easier than the too narrow hpi hard spring. It’s stiffer than stock & still offers servo saver action so unless the spring snaps don’t see there being any issues with it. Trying the stainless steel version it feels strong enough but if not can always try the slightly stiffer Mn65 spring. Maybe get it out for a test run tomorrow.

View attachment 10646

View attachment 10647

View attachment 10648

View attachment 10649

View attachment 10650

What is the link to these springs? EDIT never mind I found it

 

[Opua]

Finally pulled the front off the Kronos & threw one these AliExpress springs in the servo saver. Squared it off with a grinder 1st fits no problems & a lot easier than the too narrow hpi hard spring. It’s stiffer than stock & still offers servo saver action so unless the spring snaps don’t see there being any issues with it. Trying the stainless steel version it feels strong enough but if not can always try the slightly stiffer Mn65 spring. Maybe get it out for a test run tomorrow.

View attachment 10646

View attachment 10647

View attachment 10648

View attachment 10649

View attachment 10650

Hi Nelson, I also tried contacting you on Facebook because I read your post.
I'm looking for the Lee spring, but since it's complicated, I'll go with the AliExpress spring you mentioned. When you say you grinder it, what did you use—a Dremel? Also, when you sanded it to make the contact surfaces flat, didn't you shorten the spring? It went from 20mm to shorter, right?

 

[Nelson.81]

Hi Nelson, I also tried contacting you on Facebook because I read your post.
I'm looking for the Lee spring, but since it's complicated, I'll go with the AliExpress spring you mentioned. When you say you grinder it, what did you use—a Dremel? Also, when you sanded it to make the contact surfaces flat, didn't you shorten the spring? It went from 20mm to shorter, right?

Yes just a dremel tool with a grinding disc on it, you just want to make the ends of the springs flat like the stock springs. After trying the AliExpress spring I tried the stainless steel version 1st but had too tighten the spring up quite a bit probably better going for the 65mn spring over the stainless version.

 

[Opua]

Yes just a dremel tool with a grinding disc on it, you just want to make the ends of the springs flat like the stock springs. After trying the AliExpress spring I tried the stainless steel version 1st but had too tighten the spring up quite a bit probably better going for the 65mn spring over the stainless version.

View attachment 10711

Thank you, can you send me the 65Mn link from AliExpress?
I tried to find it, but I didn't find it

 

[Atomic Skull]

Thank you, can you send me the 65Mn link from AliExpress?
I tried to find it, but I didn't find it

https://www.aliexpress.us/item/3256808671285611.html