Crawler Steering?

[macr0w]

How come most of the crawlers I've seen or looked at don't use a servo saver?

It seems to me that it would be necessary with all the demands of rock crawling. The one time I ran my Hitec 645mg with a straight bar on it I stripped the metal gears in about 5 minutes and had to buy a new one. :002:

[suicideneil]

You are quite correct- I ran into a bench testing my TXT-1 a few years back, and it snapped the output shaft on the servo (Hitec model with Karbonite gears). I think the main reason is because a servo saver has too much 'give', even a really beefy one, and crawlers want the most steering power they can get, so they just run a normal servo horn (alloy or plastic).

[macr0w]

I wonder how often they tear up servos?

Anyone ever use one of these for steering?

[MetalMan]

If a crawler is competing on the rocks and is at a point where turning the tires is necessary to get going, a servo saver would not help at all. In regular RC cars servo savers absorb impacts from the tires being turned in a direction opposite that of the servo (where high speed is used), but crawlers generally aren't in any situations where this would be an issue (unless it were dropped onto the front wheels at an odd angle).

Originally Posted by macr0w

I wonder how often they tear up servos?

Anyone ever use one of these for steering?

I would be afraid to... 403oz./in. and it has regular alloy gears... The Hitec 5955TG puts out 333oz./in. and it has titanium gears.

[suicideneil]

The specs on that servo are nuts, but yeah, alloy gears, and the price too.....

[macr0w]

The reason I ask is I saw a crawler somewhere that was using one.

[suicideneil]

Its all about personal preference & cost I guess. That servo is wicked strong, but if the driver had a mishap and cartwheeled down a hill, if he landed on a wheel that force might be enough to damage the servo & strip the gears. With titanium gears the steering rods & knuckles would be the items to suffer. In any case, if you used it in a racing type truck, you would use some kind of servo saver, so that would still give you excellent steering response & save the servo in a crash. Im looking at the Hitec 5955TG, and the specs are fantastic- may have to get one if my dual HS645mg turns out to be poop.

[pullstarter]

Servocity have the 5955TG on sale for $79.99, 333oz @ .12 i think from memory, $30 off, if you're after a servo for huge steering I highly reccomend it and thats a darn cheap price.

[suicideneil]

WOW! Those prices are pretty damn amazing. I lookded at the 5995TG, I was almost sold on it till I saw the stall current- 4.2 amps! You would need to have a seriously good set of batteries, or very good ubec to run one of those. However.... I also looked at the 5998TG- 2 amps stall current and still 250 in/oz of torque @ 6v. I might just get one of those.....

I used to have an HS-805BB in my TXT-1, that was an amazingly powerful servo (343 0z/in @ 6v), but you cant fit one on a GorillaMaxx chassis without drill extra holes, or fabbing up some kind of mounting plate. The advantage being that it is only about $30, and gives you even more torque, plus it wont kill your batteries. Only down side is the size, but I need a big ass servo to turn my humungous wheels...... *evil grin appears on his face*

Edit: Thanks for the tipoff pullstarter!

[pullstarter]

I'm using a KO2174 on my Savage, 166oz @.13secs, it's not hugely torquey but very happy with it so far, it's enough I think.

[macr0w]

Originally Posted by suicideneil

WOW! Those prices are pretty damn amazing. I lookded at the 5995TG, I was almost sold on it till I saw the stall current- 4.2 amps! You would need to have a seriously good set of batteries, or very good ubec to run one of those. However.... I also looked at the 5998TG- 2 amps stall current and still 250 in/oz of torque @ 6v. I might just get one of those.....

I used to have an HS-805BB in my TXT-1, that was an amazingly powerful servo (343 0z/in @ 6v), but you cant fit one on a GorillaMaxx chassis without drill extra holes, or fabbing up some kind of mounting plate. The advantage being that it is only about $30, and gives you even more torque, plus it wont kill your batteries. Only down side is the size, but I need a big ass servo to turn my humungous wheels...... *evil grin appears on his face*

Edit: Thanks for the tipoff pullstarter!

Maybe next I'll go for the 5955tg. I wish I had $80.00 to drop on that before their gone. Right now I need to figure out what kind of drive shafts to use. My truck is an E-Maxx with all 3.3 driveline. But I keep breaking the ears for the u-joints. I might switch to cvd's but I'm kind of afraid of the pins coming out all the time.

Could someone tell me about or post a link to explain how and why a ubec is used? I guess they are to power a servo or other device. But I would like to see one in action. :027:

[pullstarter]

Have you tried using the hardened steel u-joints from traxxas? They're quite strong I had them on my TLT crawler and never broke a single one.

[sven]

Originally Posted by macr0w

How come most of the crawlers I've seen or looked at don't use a servo saver?

It seems to me that it would be necessary with all the demands of rock crawling. The one time I ran my Hitec 645mg with a straight bar on it I stripped the metal gears in about 5 minutes and had to buy a new one. :002:

Like others have said, in a crawler setup you would lose too much steering using servo savers. I use 5995TG servos for front and rear steering duty, with aluminum servo horns. Powered straight off the 6 cell pack they are putting out over 400oz/in. With high torque servos a plastic servo horn can be use as a weak link in the set up. You won't lose the steering like a servo saver does, but it will break/strip if something take a hit.

[pullstarter]

I used the ofna alum servo horns which have a plastic spline insert, like sven says it's a good weak link to use as they will most often strip out before the servo does.

[wallot]

Originally Posted by macr0w

I wonder how often they tear up servos?

Anyone ever use one of these for steering?

this is air servo and has first gear plastic

if JR servo then DZ9000T - have it love it.

or there is new futaba coming out in next couple weeks with 340 oz