llkoolskillet

Normally i run the Hitec 645mg servo but with my new upgrade to baja wheels i doubt the servo will be up to the task. I was doing a little reading about the HS-7955tg and the Savox SC-1256tg servos. The only differance I can really notice is the price about $30 differance. Have anyone had any luck with either? Both are titanium geared and the savox has like 30oz less torque. Which is better?

jbooker82

My Feedback: (4)

The Hobbico CS-170 is the same servo as the Hitec only it sells for 89 bucks at tower where the Hitec sells for 114

HerrSavage

I have a Hitec 5955 on steering in my Associated SC8, and it's GREAT. I have a DM-1 with the Hobbico CS-170, and it seems less great somehow - seems much slower than the Hitec 5955.. Could just be a steering geometry thing or something - not sure.. Anyway, I got a Spektrum H6040 - built by Savox - identical to the 1258 on gas/brakes in the DM-1, and so far I really like this servo. Good price, and crazy fast. I think it has kind of sold me on Savox..

That said, for steering on a Savage for bashing, the Hitec is probably the surer bet. The 5955 and 7955 are as safe a bet in RC products as you can get IMO...

Also, with Hitec I hear in the States you send it back at the first sign of issues and they'll sort you out no questions asked...

In the future though I'm going with Savox just because they're cheaper and I like what I've seen so far.. Though, yeah, that said, I'll be less certain about then than I would be with Hitec..

jbooker82

My Feedback: (4)

Both the 7955, 5955, and cs170 have the exact same specs for speed and torque. If there seemed to be a difference between them then it was probably due to being in a different vehicle / TX RX setup.

Foxy

I swear by these...they're pricy but they're the best there is.

[link=http://www.amainhobbies.com/product_info.php/cPath/61_100/products_id/18449/n/Team-Associated-DS1015-High-Torque-Speed-Digital-Servo-w-Heatsink]AE DS1015[/link]

if that's too much, its little brother is almost as good...

[link=http://www.amainhobbies.com/product_info.php/cPath/61_100/products_id/18448/n/Team-Associated-DS1313-High-Performance-Digital-Servo-w-Heatsink]AE DS1313[/link]

By the way, you don't want titanium gears in a MT. Steel is stronger than titanium. Titanium is lighter than steel, and strong enough of course, but the difference in weight between a metal gear servo and a titanium gear servo would only matter to the most anally retentive racer. These companies have got it made with everyone believing that these exotic materials are the shizz. Just remember folks, titanium=weight saving, NOT strength.

llkoolskillet

Im sorry dude but your logic on metal is a bit wrong. Titanium is 10X stronger than steel even with a high carbon content. Titanium is expensive because it requires elements that are very very expeinsive to process it into the usable titanium. Ill bet money that the gears inside these servos are not aircraft grade but the left over slag from the process. Even still they are lighter and stronger than the steel gears used.

Aircraft such as todays F35,F22,F18 use a mix of composites, aluminum, and titanium. Steel is not used because of its weight and its not as strong.

Im not hatin on ya and i do thank you for your help dude.


*I ordered the CS-170 from advantage hobby for $84 shipped. Regardless this servo with be a dramatic improvment from the Hitec 645mg's 107oz/in of torque*

HerrSavage

The internet is FULL of threads about problems with Ace servos. Some swear by them, I know.. But lots swear at them too.. I've read and heard enough to put me off. The two Hitec 5955's I've had have been truly bullet-proof.. That you so rarely if ever hear of people having issues with them has been confirmed in my case anyway by my experience with them.. Really good servos, especially for MT..

Foxy

Titanium is not stronger than steel. They do not make titanium swords. If you take two 1" thick bars, one of steel, one of titanium, and strike them against each other, the titanium bar will come off a lot worse. This is metallurgy 101 mate, I don't know where you got the idea that titanium is stronger than steel, it simply isn't.

Foxy

Yeh I'm aware of the problems. It just goes to show that you can easily lose a reputation in a second that takes years to build back up.

To my knowledge, ONE BATCH, yes, one, only a few thousand servos, was bad (and these are easily identified as they have the orange label). They'll be living that down forever. I own 8 of them and they all work today like the day they were new.

llkoolskillet

Really.... strength to weight Titanium wins.

http://www.finishing.com/106/51.shtml
http://wiki.answers.com/Q/Is_titaniu...ger_than_steel

I know my metal, im a Certified Aeronautical Welder

Foxy

The hardest carbon steel alloy has a hardness only 1 degree below ruby.

And lets not forget what we're actually talking about here. Servo gears. Anyone selecting titanium gears over steel is wasting their money (assuming that the material of the gears is the only difference). Because the weight gains from using steel gears in a servo are totally negligible (2, maybe 3 grams?). Both materials are more than strong enough for servo gears, so why choose Ti, it's weaker and more expensive?

Finally, you mention strength to weight. Well, yeh, but there are many things that are stronger than other things if you can cheat and make the part as thick as you want to. A 2" Titanium bar is stronger than a 1" steel bar, sure, but that's cheating isn't it? We're talking about a servo where the weight of the gears is of no concern to anyone. Titanium geared servos are just a stupid gimmick.

I never said it doesn't come down to what you want to use it for (in fact I thought I made that pretty clear). If you need to save as much weight as possible and titanium and steel are your options, then titanium of course. But when you want strength at ANY cost, you use steel, and I never said any different. Give me a choice I'll take steel servo gears over Ti every time.

Also, come on dude, you said 10 times stronger.

Foxy

PS. Oh look, a conflicting answer from the same 'answers' site. http://wiki.answers.com/Q/Is_Steel_harder_then_titanium . Don't use answers sites as sources, they're laughable, and that includes wikipedia itself.

RazurBlackz

I swear by my hitec.

rcairflr

My Feedback: (44)

The CS-170 is not the same as the HS-7955, it is the same as the HS-5955 and the HS-7955 are $92.75 everyday at Chiefs.

rcairflr

My Feedback: (44)

There was independent testing done on FG website, that showed that the 7955 is considerably stronger than the 5955, regardless of what the specs showed.

jbooker82

My Feedback: (4)

Ethire way I will still take a TI gear over a steel gear. Less Rotational mass inside the servo = faster responce / travel times. Just think how slow the servo would be if they used lead.

The over all weight savings isnt really inteaded to make the vehicle lighter, it is their to improve the speed of the servo.

jbooker82

My Feedback: (4)

The 5955 is no longer on Hitec's web page so I would assume the 7955 is the newer updated version of the 5955 so it could be different.

Foxy

Rotating mass on a gear that does 5 rpm? They could use depleted uranium and it wouldn't affect the rotational mass.

jbooker82

My Feedback: (4)

Take the top off the servo there is more than 1 gear. There are quite a few and they are powered by a tiny electric motor so yes what ever weight savings TI gives you it is deffinatly worth it.

Foxy

I'm starting to wonder if you're serious. Tiny electric motor? It has enough torque to lift 200 ounces or more on a 1 inch lever, you think it cares what it's gears are made of? lol.

Honestly, it's nuts thinking that gears spinning at that speed have any issues with rotating mass, or that the overall weight saving (30% in the best case scenario over a lightweight steel alloy) is anything but utterly negligible.

If you guys want Ti geared servos, that's great, no issue, but to think that the difference in either strength or weight over any other 'metal' geared servo is anything other than completely insignificant is folly. And that's the only point I was trying to make from the start.

I can't think of an application which is light enough for ti to make any difference in a servo. Anything that would be sufficiently light for that amount of weight to make any difference at all, would certainly not be using metal geared servos at all, regardless what metal.

I'll say it again; Ti servo gears are a stupid gimmick. Believe me. People will take performance over weight any day of the week, hence why the 5th scale racers use Tonegawa modified servos which are double the weight of a normal 'quarter scale' servo. Here's an image of the tone servo in my 5th scale MT, and its servo family too. The servo on the far right is an ACE ds1015 looking like it's in the land of the giants. Once again, please understand, whether the gears are made of steel or Ti is absolutely the last frikkin thing you care about when selecting a servo.

jbooker82

My Feedback: (4)

I am not talking about the physical weight of the servo. I am talking about the amount of weight the electric motor in a servo has to start / stop / reverse directions while your turing the wheels back and forth. A lighter gear train will allow the servo to move faster because it has less weight to start / stop / and reverse direction.

It is basic science.

Foxy

You are not seriously telling me that you believe that the 3g weight difference between ti and steel gears causes any difference whatsoever to the rotational mass of the servo's drivetrain, that a servo motor capable of turning the wheels on a 1/8th monster truck and has 300oz-in holding power will be affected in ANY way whatsoever? Putting a couple of screws in your inner plastic rims to balance your wheels would affect it more.

Now I'm convinced you are trolling me. Enough of this silliness. When you said basic science as well, that was a good one

jbooker82

My Feedback: (4)

I am saying it affects it's Transition Time. Do you also believe the weight of a flywheel on a motor also has no affect, cause this is the same school of thinking your using now.

Foxy

You've lost me. How does adding a flywheel (a deliberately heavy object intended to increase rotational mass for purposes of maintaining momentum) have anything whatsoever to do with this discussion. Please explain how 3 grams of gear weight makes a difference to a servo with 2lbs of monster truck wheels attached. I've been patient so far, but what you're saying is completely ridiculous. In fact, its so ridiculous I wonder how you can believe it, like I said I thought you were trolling me, but if that's not the case....I don't know what to say.

Let's use your example. A flywheel on a motor. So, we have a motor with a 2lb flywheel attached to it and the motor has enough torque to rotate a 200lb flywheel back and forth at will (in other words enough torque to NEGATE the rotating mass of a flywheel 100 times the weight). Think of the 2lb flywheel as your monster truck wheels and the 200lb example as your max torque of your servo. You add 3 grams to the comm of the motor. What difference does this make to the TRANSITION TIME of the motor with a 2lb flywheel attached?

Absolutely none.

I'm not prepared to discuss this with you further, it's a complete no brainer. 300oz-in of torque affected by 3grams in the gears? That's just funny dude, come on, admit it. If you really cared about maximising the transition time of your servo, you'd use the lightest wheels and tires on the market, which still wouldn't make much difference because the servo has the torque to compensate for heavier wheels anyway. Only when you start approaching the servo's torque limit would any added weight slow it down, and even then, 3g? It's a shame you weren't talking about overall weight, as that would make more of a difference than 3g of rotating mass in the gears. Leave the basic science (especially don't be quoting that at people again), it seems you aren't actually very good at it. Try common sense instead. Sorry to put it so harshly, but consider not typing in huge red letters when having a discussion and people might give you more leeway. According to you, people are making their servos less efficient by adding an aluminium horn, at least 3 grams heavier than the plastic ones and having a radius extending far outside the rotating axis and therefore providing a much greater amplified mass when rotated. Not to mention once again that these gears do not rotate fast enough for even a large amount of added rotating mass to make a difference.

bemeson

I have been running Savox 1256TG and 1258TG servos in my 50cc and 100cc planes for the past year. I can tell you one thing, they are tough and the centering is awesome. The beating they take on my 3D planes shows just how tough they are. I have removed all my Hitec Titanium servos from my planes due to all the glitching I experienced. If you are interested, I have several of the SAVOX's for sale due to the fact I bought a huge lot and got a great deal on them.

Brian