Big Rock I think I need a Pinion Gear Upgrade

[lee82gx]

If you are getting titanium screws please make sure to use those with extended socket depths. Better yet Torx head.

For the motor if you’re stuck, a lot of heat and but only for a short period of time should loosen the thread lock. It goes to prove that Arrma ARE using permanent thread lock, on purpose for something that is not supposed to be permanent. This points to poor design again. A patch job.

 

[Littlemotor]

I’m not sure why anyone would opt for a Ti fastener inside aluminum, especially to lock down the motor..

Couple reasons why to NOT do this would include:

Titanium is no where near as strong as even run of the mill steel. A HIGH quality Ti screw won’t be above grade 5. That’s less than HALF what factory hardware is. The ONLY reason to use titanium is because it’s lighter than steel of the same SIZE fastener. The screws you’re talking about serve the most severe duty in your rig; holding that heavy ass brushless motor in place while the entire vehicle is beat to shiit everytime the battery is hooked up..

Everything has its uses, but this job is not for a Titanium fastener. A 12.9 grade flathead screw will, and DOES do the job. Arrma has been NOTORIOUS (see what I did there?) for over tightening the absolute hell out of these screws specifically, and using Loctite that’s apparently made from JB Weld, which causes panic, and overreacting amongst new owners. The problem is the installed torque, and the mystery concrete they use as a thread locker. Don’t overthink this-remove the issues from the equation by replacing the mount screws, apply BLUE Loctite with a GOOD quality driver to said screws, allow to cure over night if it’s not the Loctite paste that comes in “stick” form, and set your mesh properly. I can about guarantee your problems will be gonezo from there on.. again-don’t overthink it, and just change every variable possible in the equation. I promise you’ll have a large time fishing out countless snapped Titanium fasters if you go for that inferior screw in this application. Just trying to help, as I’m getting the feeling you may have just not been aware of what I have layed out. Good luck with it.

 

[Spawne32]

I’m not sure why anyone would opt for a Ti fastener inside aluminum, especially to lock down the motor..

Couple reasons why to NOT do this would include:

Titanium is no where near as strong as even run of the mill steel. A HIGH quality Ti screw won’t be above grade 5. That’s less than HALF what factory hardware is. The ONLY reason to use titanium is because it’s lighter than steel of the same SIZE fastener. The screws you’re talking about serve the most severe duty in your rig; holding that heavy ass brushless motor in place while the entire vehicle is beat to shiit everytime the battery is hooked up..

Everything has its uses, but this job is not for a Titanium fastener. A 12.9 grade flathead screw will, and DOES do the job. Arrma has been NOTORIOUS (see what I did there?) for over tightening the absolute hell out of these screws specifically, and using Loctite that’s apparently made from JB Weld, which causes panic, and overreacting amongst new owners. The problem is the installed torque, and the mystery concrete they use as a thread locker. Don’t overthink this-remove the issues from the equation by replacing the mount screws, apply BLUE Loctite with a GOOD quality driver to said screws, allow to cure over night if it’s not the Loctite paste that comes in “stick” form, and set your mesh properly. I can about guarantee your problems will be gonezo from there on.. again-don’t overthink it, and just change every variable possible in the equation. I promise you’ll have a large time fishing out countless snapped Titanium fasters if you go for that inferior screw in this application. Just trying to help, as I’m getting the feeling you may have just not been aware of what I have layed out. Good luck with it.

I think its a horizon hobby thing because I encountered all these issues on every horizon branded losi ive bought as well. That stuff they use is well beyond red loctite. I butchered my LMT trying to remove a driveshaft because literally every single part was practically glued together. Even with small amounts of heat which ultimately wound up melting plastic before anything would give, they are next to impossible to move. Still though, grade 5 strength is technically plenty for a M4 bolt, the required torque to hold that motor down should be under 4 ft lbs.

 

[Littlemotor]

I think its a horizon hobby thing because I encountered all these issues on every horizon branded losi ive bought as well. That stuff they use is well beyond red loctite. I butchered my LMT trying to remove a driveshaft because literally every single part was practically glued together. Even with small amounts of heat which ultimately wound up melting plastic before anything would give, they are next to impossible to move. Still though, grade 5 strength is technically plenty for a M4 bolt, the required torque to hold that motor down should be under 4 ft lbs.

Welcome to the wonderful world of RTR vehicles.. Either way, I’m saying Titanium is an extremely poor choice for this application especially.. The shear strength (which is obviously important for a motor in a vehicle designed to beat like a red headed stepchild, religiously for its entire life) of a Titanium screw, over a 12.9 steel screw is terrible. The only reason to use titanium hardware is for weight savings. It is not a stronger screw period. When you’re talking about either 2, or 4 screws in this case (at the can, and the slide), it literally cannot be argued that it’s a better option, and at the same time-they will absolutely fail at the sole purpose of doing their job; holding the motor in place. People hear the word titanium, and immediately think that it’s the god of all other materials, and it’s simply not. It’s as I said in my previous reply; lighter than a steel piece of the same dimensions. That’s it. When you see racers using titanium hardware on their rigs, it’s generally for the top half of the vehicle, of non-critical assemblies, as they are aware of the trade-off as compared to 12.9 steel fasteners. Don’t even get me started on stainless steel screw kits…

 

[Spawne32]

Welcome to the wonderful world of RTR vehicles.. Either way, I’m saying Titanium is an extremely poor choice for this application especially.. The shear strength (which is obviously important for a motor in a vehicle designed to beat like a red headed stepchild, religiously for its entire life) of a Titanium screw, over a 12.9 steel screw is terrible. The only reason to use titanium hardware is for weight savings. It is not a stronger screw period. When you’re talking about either 2, or 4 screws in this case (at the can, and the slide), it literally cannot be argued that it’s a better option, and at the same time-they will absolutely fail at the sole purpose of doing their job; holding the motor in place. People hear the word titanium, and immediately think that it’s the god of all other materials, and it’s simply not. It’s as I said in my previous reply; lighter than a steel piece of the same dimensions. That’s it. When you see racers using titanium hardware on their rigs, it’s generally for the top half of the vehicle, of non-critical assemblies, as they are aware of the trade-off as compared to 12.9 steel fasteners. Don’t even get me started on stainless steel screw kits…

I'm not saying you are incorrect when comparing titanium fasteners to high tensile 12.9 steel fasteners, what I am saying is, in this application you are not going to hit the tensile strength failure point on a titanium bolt unless you yourself are the one doing the over torquing. Titanium fasteners are used in medical applications, aircraft, marine, and autosports racing.

A grade 5 titanium fastener from mcmaster carr in M4x20 has a tensile strength of 130,000psi. A 10.9 alloy steel bolt of the exact same size, black oxide coated, 140,000psi. An 18-8 stainless steel bolt of the exact same size, 70,000psi. So id have to say you are overstating the potential failure of a titanium bolt used on an RC car by a long shot.

 

[Littlemotor]

I'm not saying you are incorrect when comparing titanium fasteners to high tensile 12.9 steel fasteners, what I am saying is, in this application you are not going to hit the tensile strength failure point on a titanium bolt unless you yourself are the one doing the over torquing. Titanium fasteners are used in medical applications, aircraft, marine, and autosports racing.

A grade 5 titanium fastener from mcmaster carr in M4x20 has a tensile strength of 130,000psi. A 10.9 alloy steel bolt of the exact same size, black oxide coated, 140,000psi. An 18-8 stainless steel bolt of the exact same size, 70,000psi. So id have to say you are overstating the potential failure of a titanium bolt used on an RC car by a long shot.

And I have absolutely zero issues with any of the screws in any of my RC’s, but have seen titanium screws shear first hand, in countless others over the course of my 35yrs in the hobby.. That seems fairly spot on to my point, and in completely the opposite direction of “overstating…. …by a long shot”… Run whatever helps you sleep at night, as I will do the same. But I’ll continue to do it with far less headache.

 

[Spawne32]

And I have absolutely zero issues with any of the screws in any of my RC’s, but have seen titanium screws shear first hand, in countless others over the course of my 35yrs in the hobby.. That seems fairly spot on to my point, and in completely the opposite direction of “overstating…. …by a long shot”… Run whatever helps you sleep at night, as I will do the same. But I’ll continue to do it with far less headache.

Well you have certainly given me much to think about tonight regarding titanium fasteners because I use them to hold the wheels on my actual car.

 

[Littlemotor]

Well you have certainly given me much to think about tonight regarding titanium fasteners because I use them to hold the wheels on my actual car.

Awesome fella-you’re the man. Go troll someone else.