Newbie with Twin Hammers steering issue

[johnm1]

Hey all,

My son picked up a used (store demo) Twin Hammers a few months ago and loves it. However, he keeps breaking things on it and I really don't know much about these "toys". Full size cars/truck ... no problem. Mini sized ones ... ummm ... I'm lost!

The immediate issue is the steering. It was making a "grinding/binding" (?) noise and not steering correctly and has gotten to the point that he can't use it now. We took out the steering servo (the motor that does the steering) and the gear on it seems very loose which doesn't seem right. Could the servo be the main problem with the thing not steering and also with the major steering sloppiness?

What are some parts that he should get to fix the steering? It seems like a steering servo is needed but???? I also see lot's of comments about the steering bell and other things but have no idea what that is or if it's needed.

Another issue is the shop we got it from doesn't stock any parts for it so I need to know what part(s) to order and a good place to order it from. Part #'s would be really helpful.

This is my sons (he's 14) that he's worked his butt off to earn the $$ to get. He doesn't have tons of extra $$ for major upgrades

BTW: please let me know if I'm calling things by the wrong name as I have NO idea what part is what. I can figure out what "it" does but I don't know what it's called!

Thanks for any help!
John

[jgrim]

It sounds like the gears in the servo are broken. Look for a servo with steel gears with at least 150 in-oz of torque. A lot of people change out the sliding rack steering for a bell crank setup. I have not. The steering rack has a lot of play, but for bashing around it is just fine. The one weak spot I did find is the steering links. I replaced them with Traxxas links (TRA2444). You will have to shorten them about 2mm on each end. I have found the rest of the car to pretty durable as long as you do not launch it off of 6-foot high jumps or run it into curbs at full speed. Jerry

[Sr.Irie]

The steering is the big problem on these little trucks and the factory servo that comes in the RTR kits just may be the cheapest junk out there. The servo uses bushings not bearings and even new the tolerances are just awful. A quality steering servo is needed, when it comes to servos I think you really get what you pay for. I have always run Hitec servos. Not only are they quality servos but there customer service (after the sale) has always been second to none. No matter which you go with I recommend at very least, get a servo with metal gears and bearings.

As for steering there is no help for the factory setup. I produce a steering kit (Irie Products) for the TH and so does Scorched Parts on Shapeways.

After the steering is handled these trucks are quite tough. The front axles I would say would be the next thing, having spares is always good. With low power motors and religious lubrication they can last very well though. For lube use only dry lube molybdenum/graphite something without petroleum in it. Any petroleum products will just collect dirt and defeat the purpose all together.

As for a place to get parts RPP is my 2 cents. They seem to only sell things they have in stock, not middle man things like some online retailers. Which means stupid fast shipping,,,,,,always good.

[johnm1]

Thanks guys.

1. Are all servo's waterproof or just the ones that call it out?
2. How do I know it'll fit? I don't want to do any mods to the frame, etc to get something to fit. I'd rather just bolt it in.
3. Is the"Hitec RCD Digital Std Waterproof Metal Gear HS-5646WP" ok or ok enough for what my son's use? Mainly around our house and he takes it camping as well.
4. Do I need to get a replacement servo arm? I thought I read that somewhere. If yes, what do I need/look for?

Sr.Irie - I like the steering stuff that you sell. What should I order from you to tighten up the steering and keep the truck stock looking (shocks in factory position, etc)?

Sorry if I sound dumb but there are SOOO many parts that I could end up wasting money on and it might not fix the problems. And going to the RC/hobby store, while they are very knowledgeable, they cost an arm and a leg for this kind of service.

Thanks,
John

[Dbx]

The hitec is no doubt a good option. I've been running this savox servo (a little cheaper) in my hammers, mixed use, and so far so good:
Savox SW0231MG STD Waterproof Digital Servo

The bell crank steering will give the servo a much easier life, and like Sr Irie says, it's the one best mod you'll ever do. The rest of the car is really tough as far as these things go.

Edit... Generally 'Standard' size servos will fit ok. One thing that occurs to me is that anything with too high a current draw may run into problems and require a BEC. It'll depend to some extent on the stock speed controller you have, and what will work ok with that.
Hopefully someone here can advise what servos will and will not work without also buying a bec.

[Sr.Irie]

Originally Posted by johnm1

Thanks guys.

1. Are all servo's waterproof or just the ones that call it out?
2. How do I know it'll fit? I don't want to do any mods to the frame, etc to get something to fit. I'd rather just bolt it in.
3. Is the"Hitec RCD Digital Std Waterproof Metal Gear HS-5646WP" ok or ok enough for what my son's use? Mainly around our house and he takes it camping as well.
4. Do I need to get a replacement servo arm? I thought I read that somewhere. If yes, what do I need/look for?

Sr.Irie - I like the steering stuff that you sell. What should I order from you to tighten up the steering and keep the truck stock looking (shocks in factory position, etc)?

Sorry if I sound dumb but there are SOOO many parts that I could end up wasting money on and it might not fix the problems. And going to the RC/hobby store, while they are very knowledgeable, they cost an arm and a leg for this kind of service.

Thanks,
John

No not all servos are water proof. But unless you plan on playing submarine a water proof servo is not completely necessary. All servos are pretty water resistant I would say, wet grass mud things like that are ok. Also the TH's body is pretty enclosed and keeps allot of stuff out, splashes mud splatter things like that.

The steering servo on a TH are standard size.

The Hitec HS-5646WP is a big upgrade from stock but it only has 157oz-179oz of torque. I would look for the most torque you can afford and if you are going to be crawling you will want more than that. The more torque the better the steering will work. But with more torque the servo will draw more amperage and that is where your BEC of your ESC or speed control will come into play. But if this becomes an issue a dedicated BEC can be wired and there relatively cheep.

For servo arm I recommend the Losi aluminum TLR 22 arm Part #TLR1555, TLR1556, TLR1557 depending on the spline count of your servo. You must drill the hole in it for 3mm hardware but it fits well in the TH. But there are many others that will work, again the stock one is just not all that great, plastic on top of a metal hub thing, sloppy.

[Sr.Irie]

Originally Posted by johnm1

Sr.Irie - I like the steering stuff that you sell. What should I order from you to tighten up the steering and keep the truck stock looking (shocks in factory position, etc)?


Thanks,
John

My top plate and steering without tower is a bolt in item retaining the factory cantilever shock setup.

Some how I missed this question earlier I will blame it on being on my phone

[SkiSteve]

The RTR comes with this speed control I believe:
Dynamite RC: WP 60A FWD/REV Brushed ESC: Dynamite (DYNS2210)

The BEC (power supply to the servo) is 5v 2 amp max. This will severely limit your servo options unless you connect up an external BEC with higher power output. Otherwise I used this speed control for a while in my Hammer and it is great.

The stock servo has a lot of play in the output shaft as others have said but it is the sliding rack that really kills the steering performance.

The simplest and cheapest fix that doesn't require rewiring anything is to keep the stock servo, as poor as it is, and install the Irie bell crank steering kit. This will remove a lot of the steering play and all of the friction which will allow the stock servo to function its best.

The expensive and better solution is to replace the servo, and run it off a separate BEC. I installed a spectrum 6230 and a cc BEC along with Irie steering. Performance is nothing like original at all, it is precise, powerful and fast even on high grip surfaces like long grass.

[johnm1]

Thanks all for the help. My son said he wants to just get a stock replacement "thing" and worry about upgrades later on his own time (when it's not broken). He want's it running and he doesn't want to spend a lot of his own money (he'd spend mine though ... if I was willing!) and I don't like the idea of added complexity with a BEC. After lots of web shopping last night, I've found that the stock unit has been discontinued.

I've come to the conclusion that I'm overwhelmed with all the choices and I really don't know enough about these trucks to say which is the "best one" to pick for his needs and budget. We're taking the truck to our local hobby shop tonight, after work (school for him). He said they can come up with a servo set up that will fit what's needed and either they can install or I can. I'll decide when they tell me the cost for labor. They have a very knowledgeable staff and parts pricing seems OK to me so I'm good with this ... depending upon the labor costs!

I'm looking into the Sr.Irie steering upgrades (hmmm ... my son's b'day is right around the corner) as this seems like a reasonable path forward to prolong the life of the steering assembly.

Thanks again for your help!
john

[Dbx]

Sorry John. I think we failed you with too much info!
Maybe the advice could have been simplified:
'get the cheapest metal gear, 'standard' size servo, maybe think about bell crank steering some time'

[johnm1]

Yea, well ... who knows! Sometimes (ok, a lot of the time) I make it to complicated all by myself. Now, stop poking fun at me!

Anyway, the more we learn about the truck the easier it'll get. I'm not too concerned if I spend a bit more going through the store vs me finding the parts myself. I didn't even know about this site until yesterday!

It's interesting though ... the servo that came off the truck says it has metal gears.

[Natedog]

Good advice from Sr Irie and Dbx, they both make really nice parts too! Servos that are cheaper and waterproof this one has been used by many (I have not, I"m a Hitec guy) and prolly sufficient for the TH, but as Sr Irie said, you get what you pay for in servos:
Savox SW0231MG STD Waterproof Digital Servo

Hitec waterproof servo:
TowerHobbies.com | Hitec HS-5646WP Digital Waterproof HV MG Dual BB Servo

Here's a great waterproof ESC that several have said no BEC needed for powerful servos. I've used their ESC, but not this particular one:
https://www.hobbywingdirect.com/prod...nt=26223842568

Good to use the exploded view manual and do the work yourself so that you know how it all goes together, save labor money too.

[Natedog]

IIRC same steering servo that comes with Vaterra Ascender RTR, metal gears, but brass bushing on the output shaft instead of bearings. I replaced the bushing with a $1 bearing from AvidRC ordered direct, added little more grease to the gears and it worked better and had less slop, but if you can afford it, just buy a better servo now.

Edit: Vaterra has listed a replacement servo with slightly different part number.

[johnm1]

Yes, the bushing and output gear on the stock servo are brass and VERY sloppy. Side to side and in and out play.

I missed the replacement servo on the Vaterra website (that was the 1st place I looked). Either way, it looks like there's several options in the $35-45 range plus the mechanical steering fixes.

[Natedog]

OK, thought so.

Hitec would be my servo of choice, Savox second choice and I'd do the steering rack fix with Sr Irie or Dbx parts. Keep us updated and have fun!

[SkiSteve]

Sometimes keeping things stock is the easiest solution.

If I was only allowed a single upgrade to a Twin Hammer, it would be the Irie steering. Other than a sloppy output shaft, the stock servo is adequate so long as it hasn't got to force that rubbish sliding rack to overcome its friction.

The Irie steering also solves the problem of the weak front shock mount which I broke very quickly. It really is a good upgrade and a grath Bday present. I expect the shapeways one is great too.

[johnm1]

We picked up the Savox SW-0231MG yesterday at the local shop and it only cost ~$10 more than if I bought it online (I had a $5 coupon from them). It was well worth it since we got over 30 mins of the guy's time working with us tutoring us on how to get it to fit, what to watch for in clearances and how to set it up with the controller trim (?) and various other nuggets of info. We were also able to save the servo arm which saves us (my son) another ~$10.

Now on to the steering upgrades!

Thanks for everyone's help!

[Natedog]

Glad you got it fixed, good for making your son work to earn this, my parents taught me lots by doing the same. It's good to find a local hobby shop that does a good job of properly guiding and helping customers, especially new customers.

[Sr.Irie]

Good to here you got it all working. These little trucks can be a ton of fun and quite durable when setup properly.

[Fallen]

Hey johnm1, I want to encourage you that it sounds like you're doing a great job of teaching your son about a fun hobby while you learn it yourself.

Learning from those with experience about how to save money, and make repairs yourself is a surefire way to keep yourself and your son enjoying the hobby for years to come.

Over the last 3 years, my son (8 years old) and I have been getting more and more into racing at the indoor track together, and the time spent together is well worth the effort you're making. He's starting to enjoy crawling as well with my Twin Hammers, and I only hope it continues.