Droop Screws, Schock Rod Ends, and Spacers

[KevinC]

Hey Arrma nation.
I was trying to figure out why my wife was breaking shock rod ends on her K6. Running M2C droop screws and RPM arms I thought I had the droop all set nicely…….

I discovered that the droop screws had stripped out the hole in the RPM arms and with every run, the screws were migrating upwards, hence no effective droop setting.

I know I should have done this before but didn’t realize I should have put washers or spacers between the droop head and where the screw meets the arm. Here’s my fix…..a few washers and M4 nuts works like a charm. For those just running straight droop screws, I think this is a good preventative measure, and most likely the way these are supposed to be installed in the first place.

 

[jkflow]

It's those little things that make your life less miserable, good idea!

 

[Dan B.]

Nice hack! The RPM arms are much softer and those droop screw holes tend to get stripped easily. That could be a good solution!

 

[Greengaunja]

I like this and it's great because it's so simple. My road car puts alot of stress on those threads just sitting there and this prevents stripping while locking the droop in place. Another one of those moments I smack myself in the head and say "why didn't I do that after the first rpm arms stripped out". And now I can re-use those same arms again.

 

[Johnny b]

Nice fix!

 

[KevinC]

Found out again today ( the hard way) why adding a few nuts or washers will save the day. Had a bad landing with the Talion XL that drove the droop screw to its stop. Going to mod all my droop screws on my rigs to include the nuts and washers.

 

[RC Steve]

All my EXBs came out of the box with the droop screws installed from the bottom with washer stacks for spacers. It would be nice if Arrma would take the same care with their BLX line.

 

[KevinC]

Nice hack! The RPM arms are much softer and those droop screw holes tend to get stripped easily. That could be a good solution!

I agree.
After running RPM arms on the majority of my rigs, I’ve discovered there’s no real advantages to them. That schit is definitely softer than stock. On the front upper A arms, they do preclude the need for spacers which is nice but I find the pivot balls back out after time…..so it’s a give and take.

The RPM arms for the 8S rigs have no provision for droop screws…..so I’ve gone back to stockers.

Ive never had a problem with the Arrma stock arms, I just like to try different schit…..but for me…..im going back to stock. Some folks here swear by RPM…..me…..not so much.

Drive smart, stock lasts long…….

 

[RC Steve]

A truck mauler's setup.

I run all my droop screws from the bottom with spacers to stop them from compressing. Droop is set 3mm short of full shock extension, this allows room for flex. I also run travel limiters on all my shocks to keep my suspension from compressing beyond the maximum exit angle of my drive cups. At this point before a shock end or a drive cup can be damaged on any of my trucks something elts has to break first.

I had a pillerball back out of an upper RPM arm Saturday and it cost me a M2c drive cup.

 

[Dan B.]

I agree.
After running RPM arms on the majority of my rigs, I’ve discovered there’s no real advantages to them. That schit is definitely softer than stock. On the front upper A arms, they do preclude the need for spacers which is nice but I find the pivot balls back out after time…..so it’s a give and take.

The RPM arms for the 8S rigs have no provision for droop screws…..so I’ve gone back to stockers.

Ive never had a problem with the Arrma stock arms, I just like to try different schit…..but for me…..im going back to stock. Some folks here swear by RPM…..me…..not so much.

Drive smart, stock lasts long…….

I totally agree. The only better a-arms I’ve ever tried that were a definite benefit over stock ones were (let the flaming begin, don’t stab me, bro…) the Traxxas HD arms. They didn’t break when it was cold, they didn’t sag like the RPM ones, and have literally held up for years on two of my old bashers. The TA “Hard” arms are also good, but in all fairness the Team Associated trucks I have them on are really light. And neither of those platforms has droop screw holes to strip out.
After trying them several times on several different brands and scales, I won’t be buying RPM arms ever again.

 

[SrC]

Hey Arrma nation.
I was trying to figure out why my wife was breaking shock rod ends on her K6. Running M2C droop screws and RPM arms I thought I had the droop all set nicely…….

I discovered that the droop screws had stripped out the hole in the RPM arms and with every run, the screws were migrating upwards, hence no effective droop setting.

I know I should have done this before but didn’t realize I should have put washers or spacers between the droop head and where the screw meets the arm. Here’s my fix…..a few washers and M4 nuts works like a charm. For those just running straight droop screws, I think this is a good preventative measure, and most likely the way these are supposed to be installed in the first place.

View attachment 318403

I noticed my Fireteam is the only Arrma that came with washers on the droop screws out the box. I first thought it was rather odd. Then it made some sense to me. For the same reason you stated above, I am sure. I added some more washers to get my droop where I wanted it.
Good call there.
Yeah Rod ends usually break because of Arm over extension force. Proper droop is key here.
And RPM Pure Nylon is softer than Stocker Arrma Composite arms, so droop screws would push through and strip out. Especially if you boil your RPM arms in water for more flexibility.

 

[slick2500]

I agree.
After running RPM arms on the majority of my rigs, I’ve discovered there’s no real advantages to them. That schit is definitely softer than stock. On the front upper A arms, they do preclude the need for spacers which is nice but I find the pivot balls back out after time…..so it’s a give and take.

The RPM arms for the 8S rigs have no provision for droop screws…..so I’ve gone back to stockers.

Ive never had a problem with the Arrma stock arms, I just like to try different schit…..but for me…..im going back to stock. Some folks here swear by RPM…..me…..not so much.

Drive smart, stock lasts long…….

Over the years I have learned that Rpm is more hype than anything else. I have tried their products on numerous vehicles to only be disappointed time and time again. By far the worst product of theirs that I have tried is the tranny case for the Traxxas 2wd vehicles, the metal motor plate is seriously the only good thing about it, the rest of the tranny case is garbage because they use the same nylon on that as they do their a arms which is way too soft for a tranny case, none of the screws will tighten down, there are gaps in the case all over the place and the case flexes so bad that I dare not give it too much power for fear of stripping out the tranny gears.

 

[Dan B.]

Over the years I have learned that Rpm is more hype than anything else. I have tried their products on numerous vehicles to only be disappointed time and time again. By far the worst product of theirs that I have tried is the tranny case for the Traxxas 2wd vehicles, the metal motor plate is seriously the only good thing about it, the rest of the tranny case is garbage because they use the same nylon on that as they do their a arms which is way too soft for a tranny case, none of the screws will tighten down, there are gaps in the case all over the place and the case flexes so bad that I dare not give it too much power for fear of stripping out the tranny gears.

I totally agree. For the TRX 2wd trans cases I’ve gone exclusively to their more recent 272R case they started putting on the Drag Slash.
I‘ve hated RPM arms for years. Granted, they don’t break as easily. But that is the only real benefit and is (to me) far overshadowed by sagging, exhibiting way too much flex, and having everything threaded to strip almost immediately.

 

[SrC]

Yeah all of RPM nylon is the same no matter which parts they mold.
For most smaller 1/10 scale RC's the arms do work out ok, if you don't mind added flex.
RPM never beefed up their Nylon formula or improved part designs better for the larger much heavier 1/8 and 1/5 platforms.

 

[slick2500]

I totally agree. For the TRX 2wd trans cases I’ve gone exclusively to their more recent 272R case they started putting on the Drag Slash.
I‘ve hated RPM arms for years. Granted, they don’t break as easily. But that is the only real benefit and is (to me) far overshadowed by sagging, exhibiting way too much flex, and having everything threaded to strip almost immediately.

272R is so nice. The VXL models come with it stock now. Sadly Rpm is the only option other than stock in so many cases. I have my Rustler wide modded so I can run the same offset wheels front and rear but without Rpm that would not be possible as Proline has discontinued their Protrac kit for the Slash.

Yeah all of RPM nylon is the same no matter which parts they mold.
For most smaller 1/10 scale RC's the arms do work out ok, if you don't mind added flex.
RPM never beefed up their Nylon formula or improved part designs better for the larger much heavier 1/8 and 1/5 platforms.

Even on my Rustler the a arms warped.

 

[SrC]

On my TA 2 10T's and 2 GT's, the RPM arms are still fine. Old stuff here. And very lightweight platforms.

 

[Dan B.]

272R is so nice. The VXL models come with it stock now. Sadly Rpm is the only option other than stock in so many cases. I have my Rustler wide modded so I can run the same offset wheels front and rear but without Rpm that would not be possible as Proline has discontinued their Protrac kit for the Slash.


Even on my Rustler the an arms warped.

My solution (without the ProLine kit or other mods) is to simply run the front wheel offset at all four corners. It does widen the rear track slightly but I consider that to be a benefit, especially on the RWD rigs like the 2wd Slash and Rustler. I never really understood why everyone didn’t do this. It’s an easy, no mod way to run the same offset all the way around without putting your glasses on to see the F/R stamps on the wheels.

 

[slick2500]

On my TA 2 10T's and 2 GT's, the RPM arms are still fine. Old stuff here. And very lightweight platforms.

I have NOS Rpm a arms on my B2 the material is different from what they use now. They are much firmer than the arms on my Ruckus, Stampede, Rustler, Merv, Typhon 3s or the 6 pairs I have for the Arrma 6s line.

 

[SrC]

I would venture to guess that the NOS Nylon just got hardened with age??

It's possible.
I found Nylon even gets brittle over time. Years and years....

 

[slick2500]

My solution (without the ProLine kit or other mods) is to simply run the front wheel offset at all four corners. It does widen the rear track slightly but I consider that to be a benefit, especially on the RWD rigs like the 2wd Slash and Rustler. I never really understood why everyone didn’t do this. It’s an easy, no mod way to run the same offset all the way around without putting your glasses on to see the F/R stamps on the wheels.

I honestly cannot understand why Traxxas designed the vehicles like this in the first place. It makes no sense to have to make 2 different offset wheels for the front and rear when all 4 could have easily been the same had they just made the front a arms a little bit longer. The camber and steering links they already make anyway.