Savage bellcrank and dual servo saver mod

[Gee]

Hi Guys,

First off I searched and didn't see any mods like this in the searches I did. I don't want to steal anyone’s thunder if the mod has already been posted up somewhere. I am sure I was not the first one to do something like this, posted or not. We are all here to share what we know to make the Savage even better then it already is. If it is posted up else where, all I can say is. Smart Fellow! Heck of a good idea! Must be a pretty creative person. A Norwegian possibly. Good show Old Chap! etc. etc.

I have been fighting steering slop every since I got in the hobby and it drives me crazy even though I can drive a straight line unless I remove my hand from the steering. I’ve tried the stock bell crank, added the bearings, bought aftermarket Integy, and lastly combined the two. I used half Integy half stock servo saver on the XL. Now that made best improvement so far. I was surfing eBay and found a XTM MT bell crank listing that was about to end and no bids. So I bid and won it for .99 plus shipping. The rest is history and in the pics. If you choose to try the mod out with a different bell crank setup just make sure the arms that connect to the drag link are not too long. I got lucky and the XTM fit nicely. The XTM setup has flanged bearing in the drag link that can be used. It has bushings instead of bearing for the posts. If you have bearing in your current setup they should fit into the XTM setup.

My Savage XL is the one that really needs neutered. It likes to wander the neighborhood when ever I take it out. I've converted it to brushless for the winter and picked up a X SS roller since last visit. The X SS upchucked it's first 13t bevel gear. So I had the X SS opened up so and it got the first XTM setup I had. I have another one in the mail for the XL and can’t wait to put it in the XL and try it out. It should make a bigger difference in it having the larger and heavier 40s and a servo saver that don’t know it own torque. The improvement in the X SS is noticeable even though it handled pretty well already. Anyways here’s what I came up with. Hope it helps anyone that gives it a go….

This was the first Nitro forum I joined so my loyalty is here and this is the first nitro forum I posted to. This will help with the slop in your steering and also improve the soft feeling of the stock servo saver spring.

 

[olds97_lss]

Kind of cool... but I don't see the need for it. What is it that two springs give you that one spring doesn't? Is it because the stock spring is too soft? Might have been less hassle to find a stiffer spring. Actually, since your only connected to one horn, the two springs don't do anything for you... did you do it for the bearings in the center link?

I remember when I did the "monster pirate" mod back before the cam steering/saver was available from HPI... now that I type it out, I do notice the stock spring is a bit softer than I'd like. I didn't notice it so much when running t-maxx stock chevrons. But with revo sized tires or savage GT1 tires (originals), it does wander a bit.

 

[Gee]

This isn't a mod that every Savage may need.

You’re well respected in the forums OLDs. I for one respect your opinion and have gotten a lot of help from you directly or through reading your posts and threads. So I will entertain you skepticism. I am sure your setup doesn't see a need for a mod like this. Heck, I for one have never had Mid Tank Lean problem on my Savages but I haven't expressed to others it was a mod that was unnecessary on their setups. So let’s take a look at this with an open mind that there are Savages that are setup differently and that it may make an improvement to them that can’t be gotten by something as simple as a stronger spring.

The install on the X SS wasn't as necessary as it is for my XL. I am sure my XL is just as heavy as the others are. They have to be close anyway. In my reading it seems that most of XL owners run smaller tires then the forty series. I think my XL look like it is wearing high water jeans with mismatching sock with any tire smaller. The heavy and bulky tires take its toll on servo saver spring HD or not. They take their toll out on other parts also. There's a price to pay for running them. To move them heavy tires you need a servo that has no problem compressing the servo spring. Like I mentioned I've tried different setups and several different HD spring. All of them eventually were tightened down so tight that there was no saver for the servo. It may be hard to picture if you’re thinking that the servo saver arm is only connected to the servo itself. Not hard to picture when you grab the setup and force it to turn with you hands. The two springs work together now. One more then the other but the other provides enough give that when the first saver is at a certain tension the other one kicks in. Providing much more resistance at that point then the single saver would if it was continued to be compressed.

As far as how it has removed the slop for my system so effectively is something I can explain. It has helped my setup.

Is it a mod that is needed for every savage or your savage? I can't answer that. All I can say is it has made a difference on my setup.

This was just a mod that I did on my setup that helped me. I went through the progression and spent the money and time on my setup. This is where all of that has led me to. Everyone is more then welcome to spend the money and time trying the ball bearing, stronger springs, the after market bell cranks, etc. to improve their setup if they feel the need. Your right though, maybe all that they need is a stronger spring. That wasn't the case in my setup. For me winning the auction at .99 cents was cheaper then any of the stronger springs had cost me. It was a little more work but I was up to the challenge and enjoyed doing it all the same. The drag link is the only mod to the stock that isn't reversible. A set of flanged bearing installed in the stock drag link couldn't hurt even if it is reversed. Some don't like bearings in the bell crank area. I like a smooth no slop bell crank setup. But each to their own...

 

[olds97_lss]

I didn't mean any offense, was just trying to understand what good it does. Without running two servos (one on each "saver" arm), there's no way that second spring does you any good. Which is why I was trying to figure out the "why" when reading through this and looking at photo's.

I'd venture to guess that if you replaced the post/pieces not connected to the servo with stock and left the XTM one on the one connected to the servo, you'd get the same amount of pressure before the saver kicked in.

It's just more likely that XTM's spring is stiffer which is why you see an improvement. Or, it's geometry of the arms/ears that come off the saver itself causing more resistance required to overcome the spring. If the arm connected to the drag link was shorter, it would give it less leverage to overcome the saver spring.

Got a photo of the two linkage sets sitting side by side as a reference for horn length?

 

[Gee]

No offense taken. I remeber you were the skeptic or cautious one when I posted my idea about a better way to mount the Nova RC engine mount. You keep us from rushing in head first OLDS. I am not offended by that. If something works better I accept that it does. That's just my nature. My guess on why it makes an improvement was just my thought on it. I know that there is a lot of force on the outside of those huge tires when ever I turn the wheels at 35mph or out bashing through the rocks and mud. How that plays into the two springs and why it removes the slop is beyond me really. In the end I am not a physicist(sp) or anything like that. I can only say it works better then any other bell crank with a HD sping on a single arm servo saver that I have ever tried. Just an FYI I am not just basing this improvement on one install of of a dual servo saver cam to a bell crank. The X SS in the pictures was the third one and the third one that made an improvement.

Around 21 months ago after reading about the mod to the emaxx to improve the steering. I tried it out right away.
http://monster.traxxas.com/showthread.php?t=403852&highlight=e-maxx+steering+slop

I've run the same type of dual servo saver bell crank on my FLM Maxx for almost 2 years now. It made a huge difference with the maxx but I never bothered to find out actually why it made the difference.

I am not sure why I didn't think of doing the same to my Savage earlier though. Instead I tried the bearing, hd springs, $35 after market aluminim Integy Bell Crank. I guess just seeing the auction is what make it click for me to try the XTM in the savage. I have an Integy and a Stock servo saver in the XL setup. My second attempt at duals, but first on the Savage series while I was waiting on the XTM bell crank toarrived. That mix & match setup has made an improvement. I don't see how it can just be the springs in the XTM or the size of the arms that made the improvement there or in my FLM MAxx. After installing that additional spring/cam to the XL bell crank is when the improvement was made in the XL. That install has two different types of springs, arms lengths, and cam setups. Yet it made an imporvement.

Sorry I can get to rambling at times. I can't explain why/how it makes the difference. Maybe someone else can. I can say based on experience alone of doing and using it on three different setups. With three totally different bell cranks, springs, servos, and cam types. It does work. I'll still post up some pics of the XTM next to what I pull out of the XL when I do it.

 

[olds97_lss]

The only thing that makes any sense about reducing slop is on that link you provided for the emaxx issue. It's issue was due to the slave post not having bearings and would require bearings that are very small which would probably die quickly. By replacing the slave cam with a servo saver cam, it allowed the guy to use larger bearings to reduce the slop/wear. After reading it further, he ended up with it connected to the servos just like yours. Both servos connected to one cam. The other cam is still just a slave like yours.

So, out of that, the only thing that makes any sense is that the saver cams you have have tighter tolerances compared to the slave cams you have which reduces slop.

All of that said... the next time I tear my savage down, I'll make sure to take a look at the parent/slave posts and look for any additional slop. I know my spring is a bit on the soft side because the servo I have in it easily overpowers it if I hold the tires stationary. From what I read above in yours, you apparently found a stiffer setup (either spring or the V is more pronounced) with the parts your using.

Which parts/brand are you using now that is connected to the servo that you noticed to be a stiffer setup? Would be interested in picking those up before I tear into mine.