Limitless Scorched RC or TRC center shafts

[Luigibell78]

Have those also......

I felt the same way about the RCAWD shafts. A modest upgrade at a modest cost.

BTW, I tried the Ball Bearing Drive shaft support found on the V2 Infr, Fel.
Do yourself a favor and don't get them. If you have a V2, take it off ASAP. IMHO. The bearings lasted about 2 Speed passes at only 84MPH in my LIM. Bearing Seals exploded on both bearings, and bearings got loose and scored the Shaft. Did more damage and made a crap load of noise. Waste of $12. trying it out on the stock Lim. rear shaft. Just take them off on your V2's, Get a better rear shaft. I felt speed took a hit also, from the friction against the shaft. What was Arrma thinking. That Band-Aid fix is useless in the V2's.

You have any pictures of this bearing support system from arrma?

I looked at the exploded parts view of the v2 infraction and i didn't see anything different other than that handbrake thing.....

 

[SrC]

^^^
CENTER DRIVESHAFT HIGH SPEED SUPPORT SET (ARA311027) | ARRMA - Designed Fast, Designed Tough (arrma-rc.com)

Its listed as a "Standard" part now for V2 Infr. and Felony. It is not included with the current Limitless. Don't even attempt to do speed runs with this part. Best to run without it.... If not a better upgrade rear Dr. Shaft.
Remove it if you have it on your Fel or V2 Infr. My recommendation at least. It's that bad. IMO.

Don't waste your time and money on this cheap attempt of an Arrma Band-Aid part if you have a V1 Infr. or Lim. I wouldn't be surprised if Arrma removes it from production. It is that bad. Mechanically the design to prevent shaft oscillation is an Arrma Failure. They were too cheap to create a better Driveshaft. The correct way to fix this major issue. IMHO. (Instead they used 10 cents worth of plastic, (2) 3mm screws and (2) 25 cent bearings that were crap out of the package)
Just get a quality rear driveshaft. And be done with it.

BTW, be careful when/if spooling up your Lim., Infr. or Fel. on the bench under power, that very long Drive shaft can become a projectile and take out an eye for sure. Be careful. Even with the body in place that DR. shaft will eject real fast IMHO. With motor spinning at 50-60k Rpm's.
Innovation RC had a YT video showing how bad the stock shaft is. It deflects violently. There is no way that stupid Arrma Part fix can control it. The 2 bearings exploded real fast on mine. It scored the drive shaft and all. Within the first Lipo pack.

 

[SrC]

You have any pictures of this bearing support system from arrma?

I looked at the exploded parts view of the v2 infraction and i didn't see anything different other than that handbrake thing.....

ARRMA Radio Controlled Cars (RC Cars) - Designed Fast, Designed Tough (arrma-rc.com)

It's there. Just behind the Rear Driveshaft and boxed off in grey dashed lines.

 

[Luigibell78]

Ahh i see it now... strange design and definitely kinda pointless in that location. Needs a support in the center not at the rear.

Im waiting for TRC shafts. The rcawd shaft still has a crazy wobble.

While it looks bad on a bench test i wonder if under load on the road if the vibration isn't as bad?

TRC performance shafts are nicely made, I got 3 sets of them and haven't had any issues with them as of yet. I never had scorched shafts to compare but haven’t heard any bad reviews on them too.

View attachment 121597

They look beautiful.

Do they clear the stock chassis braces?

 

[Liquid SSSnake]

Someone needs to set up a camera inside and see what the "cheap" driveshafts do under load. It's not ideal to rev the tires and everything else to the moon on the bench... or a real car on jackstands.

Although, if it's balanced on the bench then it's good.

I just found out the other day if the input cups have crud in them they wobble! I was trying to figure out if the cup or pinion was bent, just 0.2mm of dirt in the cup.

 

[fasterhobbies]

Anyone running gpm shafts at higher speeds?

 

[Luigibell78]

Have those also......

I felt the same way about the RCAWD shafts. A modest upgrade at a modest cost.

BTW, I tried the Ball Bearing Drive shaft support found on the V2 Infr, Fel.
Do yourself a favor and don't get them. If you have a V2, take it off ASAP. IMHO. The bearings lasted about 2 Speed passes at only 84MPH in my LIM. Bearing Seals exploded on both bearings, and bearings got loose and scored the Shaft. Did more damage and made a crap load of noise. Waste of $12. trying it out on the stock Lim. rear shaft. Just take them off on your V2's, Get a better rear shaft. I felt speed took a hit also, from the friction against the shaft. What was Arrma thinking. That Band-Aid fix is useless in the V2's.

Rcawd now makes a copy of this shaft support system. It's available on eBay and made out of aluminum.

Im skeptical about it's benefit after hearing about your experience with it.

 

[SrC]

I understood the long rear driveshaft issue from day one. V1 Infr and Lim. I have.
RCawd is just one option in the alloy support variant. It is copied and available for real cheap on AMZ and EBay.
I decided to try the RCawd shafts on my Infr. ( 1mm thicker than stock and 2mm longer) and the $Amped RC$ 8mm( and 2mm shorter) shafts on my Lim. Skip that shaft support. Alloy or plastic doesn't make a difference IMHO. The bearings will blow out, the rear shaft will get scored up, and vibration is still there with the support. Additional Friction against the driveshaft makes no sense either.
It is just a cheap band-aid fix Arrma used. They could have spent more in making a better thicker rear shaft. The correct way. The front shaft is not any issue and can be left there. RCAWD sells the rear drive shaft separately. All you need. The expensive Amped RC. (Markhor)s only comes both in a set. $100. (better I think but costly)
I am curious why not many v2 Infr and Fel guys don't comment much about the stock plastic Dr. Sh. support.
Notice that only the Limitless was never upgraded to date with this BB DS support. Speed run guys are NOT using it at all. All the hardcore YT'ers at least.


EDIT:
The stock plastic support as well as the alloy version just sit "floating" and sandwiched between the 2 battery trays. Not fastened. Only, the Arrma kit gives you one additional plastic support bracket used in a single battery tray setup and it uses one chassis screw to secure the side where the battery tray was removed. It becomes fixed at one end. FWIW. I use the dual tray setup.
I would like to hear comments that are pro this fix if any and why it works for them. I know many have replaced the smallish included bearings that brick almost instantly. I cant see that it becomes any more functional however. I wouldn't think so.

 

[Liquid SSSnake]

I just finished my rebuild recently, I had the RCAWD support before. I just put Arrma metal diffs in, (and cleaned the outdrives) the vibration is better than I remember. Not bad, I'm sure there is some drag and I still think aftermarket shafts are better solutions.

 

[SrC]

I got PTSD from your video.

 

[parcou]

I just finished my rebuild recently, I had the RCAWD support before. I just put Arrma metal diffs in, (and cleaned the outdrives) the vibration is better than I remember. Not bad, I'm sure there is some drag and I still think aftermarket shafts are better solutions.

And others...what is the verdict on the RCAWD? Is it a good upgrade over the stock Infraction v1 center dogbones?

 

[Sloclone100]

I don't have them. But Scorched RC seems popular. If they are wider, make sure they will clear the F/R chassis braces. The fatter drive shafts can hit or rub the braces. Never heard of TRC in the states. Team Raffe from Hong Kong?? I couldn't locate those TRC's in any search.
Can you send me a link for the TRC center shafts?

Around 1986-88, I had a 1/10 scale pan car made by TRC. They were one of the early companies that helped shape the future of 1/10 foam/carpet racers. And, along with Associated, began a new style of chassis. Tamiya was still using the "bathtub chassis" and, of course, they made many off-road buggies and trucks. Tamiya always included beautiful bodies/decals.

But my first serious 1/10 pan car was the TRC. I still have the instructions somewhere.

 

[SrC]

^^^ Yeah my first RC was the 10L. Im surprised many of the old school RC companies are still around. But that's a good thing.

 

[FatCatRC]

People really need to stop using Kevin Talbot as their be all end all rc god. The guy is usefull for one thing, a good laugh and that's it. He's only good at smashing rc's and selling you his ebay scam. And scorched parts are just traced out arrma parts on titanium. Thicker parts more mass moving =harder on drivetrain.

 

[Liquid SSSnake]

Around 1986-88, I had a 1/10 scale pan car made by TRC. They were one of the early companies that helped shape the future of 1/10 foam/carpet racers. And, along with Associated, began a new style of chassis. Tamiya was still using the "bathtub chassis" and, of course, they made many off-road buggies and trucks. Tamiya always included beautiful bodies/decals.

But my first serious 1/10 pan car was the TRC. I still have the instructions somewhere.

I feel like this is a different TRC, just a little guy on Facebook... I could be wrong. He directed me that he was selling his shafts on Just Bash It, so I grabbed a set.

I just installed the shafts, I haven't driven it yet. I'm trying to hold out on more silver hoons before it gets warm outside again.

 

[joshjosh]

I agree with you. I tried it out. Because wanted to see how bad Arrmas fix would be. I have RCAwD shafts and Amped RC 8mm shafts here. This thread got me motivated to install the AMPED RC shafts and matching F/R braces. Need the braces. My HR braces would rub the shafts. took me 20 min. Done playing around with the stock shafts. I will put the RC Awd in the Infr. With the HR braces. the Amped RC shafts were $92.plus shipping. For the pair. RC awd shafts and can be purchased separately. honestly, you only need the rear shaft. I use SS springs at the center spool output cups. Keeps the shafts in position better.

View attachment 123710

View attachment 123711

View attachment 123712

View attachment 123713

I know this is a bit off topic here, but your cap pack is too far back. At that distance from the ESC, it isn’t doing anything for keeping the ESC voltage stable.

People really need to stop using Kevin Talbot as their be all end all rc god. The guy is usefull for one thing, a good laugh and that's it. He's only good at smashing rc's and selling you his ebay scam. And scorched parts are just traced out arrma parts on titanium. Thicker parts more mass moving =harder on drivetrain.

I’ve had exceptional luck with ScorchedRC parts. Just because the parts are thicker, doesn’t mean they have more mass. In general, titanium is 45% less mass than steel. Even if you doubled the shaft size, it would only be slightly more mass. I run the speed run center shaft replacement, and the rear titanium shaft replacement from ScorchedRC. Love them both, the center shaft definitely solved any wobbling issues, and fixes the geometry in the process.

 

[SrC]

I know this is a bit off topic here, but your cap pack is too far back. At that distance from the ESC, it isn’t doing anything for keeping the ESC voltage stable.

I am using 10 guage cap wire matching the Lipo's guage. I understand what you are saying regarding length of the Cap pack wires. In theory, more length is more resistance. There is a formula and limit based on guage.
However, using 10 guage (minimal resistance) and most importantly the fact that my Cap Pack leads terminate within 1 inch of the ESC main board is the key. Especially with any Cap pack installation. I could have made the wire shorter by soldering far from the ESC, but this is just not correct for ripple control. As long as the cap pack terminates well ahead of the lipo, you are good. In a perfect world I would have placed the Cap pack on top of the ESC. Just not practical. I wanted the Cap pack central and mounted to the T2T brace. My rig is weight balanced/ crossed balanced. Many use this position for a cap pack running the motor in the stock left side position.
Thanks for your input.

 

[joshjosh]

I am using 10 guage cap wire matching the Lipo's guage. I understand what you are saying regarding length of the Cap pack wires. In theory, more length is more resistance. There is a formula and limit based on guage.
However, using 10 guage (minimal resistance) and most importantly the fact that my Cap Pack leads terminate within 1 inch of the ESC main board is the key. Especially with any Cap pack installation. I could have made the wire shorter by soldering far from the ESC, but this is just not correct for ripple control. As long as the cap pack terminates well ahead of the lipo, you are good. In a perfect world I would have placed the Cap pack on top of the ESC. Just not practical. I wanted the Cap pack central and mounted to the T2T brace. My rig is weight balanced/ crossed balanced. Many use this position for a cap pack running the motor in the stock left side position.
Thanks for your input.

I would disagree with you, the issue isn’t the resistance of the wire, which is solved by bigger wire. It’s the inductance of the wire, which cannot he solved by bigger wire. Having longer battery/capacitor wires truly matter.

 

[SrC]

Inherent Self Inductance of straight wires cannot be defined.
And there is a relationship with larger guage wire and higher inductance to some degree.
For the purpose of RC in this application, it is a moot point. Negligible impact on inductance values
In Theory your argument makes sense. However, self inductance of straight wires ( non coiled) is not calculated to the extent of this application. A simple Capacitor circuit. Resistance across this circuit takes priority. I will agree, shorter wires are always better. Short as feasibly possible.
I have aprox. 15 Cm in length of 10 AWG Cap wiring that terminates within 1 inch of the ESC PCB. Some ESC mfr's use external Cap packs with very thin guage and long wires. I don't agree with that. But it appears to work, as long as the wires terminate within 1 inch of the ESC power leads at the PCB. Most important.
IMHO.
Always open to discussion.
Good topic.

 

[joshjosh]

I agree, this is a great discussion. Again, this is a small critique on your amazing ride, in no way should this be considered anything but. The thing to remember here is the motors are 3 phase AC motors, your ESC is the DC to AC converter, so typical DC theory doesn’t fully apply. The voltages surge at times, and the job of the capacitor is to hold that surge for brief periods. The further away it is from the spike, the less effective it is (this is why they emphasis 1” distance). You battery is a far better capacitor, the reason for in-line capacitors are to make up the distance/inductance from the ESC to the batteries. With the capacitors on the ESC being much closer than the cap pack, the path of least resistance for the voltage surge is for the ESC to absorb the surge (as it would normally do), almost bypassing your cap pack entirely. Here’s the best analogy I could find;

Explanation/theory
First a watery analogy, water running in a pipe and through a tap. Now turn off the tap quickly. You'll hear a loud knock/shock sound in the pipe. The water wants to continue flowing but it can't, for a moment the water pressure is much higher than the static water pressure. It's the same for a current that's switched off, because of the inductance it wants to keep on flowing, voltage gets higher. This is also what causes sparks (brush fire) in a brushed motor.

The controller is like a watertap that's switched off (and on) very fast (8,16, 32kHz PWM) to get the desired current. Turning off the current, in combination with the battery wire inductance, causes voltage spikes because the current wants to continue on its course (ref. inertia of the moving watercolumn). Those voltages are higher than the battery voltage. The input capacitors (cylindrical) takes care of these spikes (they reduce the wire inductance). The longer the wires, the higher the voltage spikes induced in the wires, the harder on the input capacitors. They will get warmer, heat up and explode. This is caused by the wire inductance, not by wire resistance. Therefore, using thicker wire will not help much, it's not a bad idea either, but extra capacitors are the solution, thus reducing/compensating the wire inductance. Or longer motor wires instead of long battery wires.