Kronos XTR Will droop screws eventually puncture through the chassis?

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DaniC said:
Wow nice comprehensive list of possible solutions! Thanks for taking the time to ask around and put it together!
I did think about number 1 but I felt that whatever I put there would fall very quickly.
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Losi for a time had steel mounting plates, held in with 4/40 imperial screws. Nicer way of doing it vs gluing feeler guage, though either way is effective.
 
Installed the Tekno screws and I'm pretty sure this will solve the problem! It might still mark the chassis etc but it will not puncture through it like the grub screws where doing. All droop screws should be like this!
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Forgot to mention, the screws need to be installed from the bottom obviously, as opposed to the grub screws which are installed from the top. The simplest way to do this it by removing the shocks at the lower end from the arm, then on the back remove the rear hub and this allows you to remove the dog bones and then you can flex the lower arm upwards to have enough room to put the screw in without having to remove the arms completely or having to separate the front/rear gearbox assembly from the chassis. The front arms is a similar process, but it's easier to remove the upper arms instead of the steering blocks.
 
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Fireblade said:
the titanium droop screws I have have a big mushroom head on the underside, it spreads the load.
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There's a joke or two that could be made from this statement :cool:
But seriously, yes, button head screws will minimize the gouging of the chassis.(y)

I do wonder, how likely is it that a chassis will last long enough without being otherwise damaged to the point of being unusable before the gouges of a button head droop screw will render it unusable? I suppose a 6000 series aluminum chassis will likely wear through before the 7000 series as used on the XTR or Sketer, but honestly can't imagine the wear being a significant concern. Especially for a basher rig. Maybe it's just me.
I have a 15 year old Xray buggy that shows no concerning wear, also a 12 year old Thunder Tiger MT which is still going strong.They're bashers. If I were a dedicated racer, I'm sure I would be more interested.
 
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DaniC said:
Installed the Tekno screws and I'm pretty sure this will solve the problem! It might still mark the chassis etc but it will not puncture through it like the grub screws where doing. All droop screws should be like this!
View attachment 2987
View attachment 2988
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View attachment 2990
View attachment 2991
View attachment 2992

Forgot to mention, the screws need to be installed from the bottom obviously, as opposed to the grub screws which are installed from the top. The simplest way to do this it by removing the shocks at the lower end from the arm, then on the back remove the rear hub and this allows you to remove the dog bones and then you can flex the lower arm upwards to have enough room to put the screw in without having to remove the arms completely or having to separate the front/rear gearbox assembly from the chassis. The front arms is a similar process, but it's easier to remove the upper arms instead of the steering blocks.
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That clearly seems to work out OK, fit-wise. I wonder if it will significantly reduce the wear? Keep us posted!
 
As you see Mugen Truggy after 300 batteries (race)! Which basher runs 300 batteries in 5 months??? My bashers are after 150 batteries for the ton !! (Bearings / gears, etc., the repairs exceed the who of the vehicle)!

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Koma71 said:
As you see Mugen Truggy after 300 batteries (race)! Which basher runs 300 batteries in 5 months??? My bashers are after 150 batteries for the ton !! (Bearings / gears, etc., the repairs exceed the who of the vehicle)!

View attachment 2999
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Yes, I didn't mean to ridicule anyone. I just don't see the wear being any significant issue for a basher.✌
 
Koma71 said:
As you see Mugen Truggy after 300 batteries (race)! Which basher runs 300 batteries in 5 months??? My bashers are after 150 batteries for the ton !! (Bearings / gears, etc., the repairs exceed the who of the vehicle)!

View attachment 2999
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Q: What basher runs 300 batteries in 5 months?

A: A basher that runs their rig twice a day (on average) over 5 months.
 
OK, after some thought and trying to be as as logical as possible, this is what I'm going to use:


Screenshot_20220911_152926_com.android.chrome_edit_13603643996360.jpg

I think the Titaniam droop screws are 41 on the Rockwell hardness scale, vs the 7075 chassis which is 53.5.

Therefore, the softer, domed droop screws cannot gouge the chassis ears.

Additionally, these will afford a greater range of adjustment, especially for those who run off road and need to dial in some extra droop from time to time (as I often do) .

You could also use these, if you prefer button head shape - but they can only be adjusted from the top.

Screenshot_20220911_154400_com.android.chrome_edit_14470902597791.jpg

You can get them with Allen sockets at both ends from DMS racing in the UK, they're 12mm - no biggie - they can always be trimmed to 10mm. Left as they are, the 2 extra mm will be through the top of the arm where you adjust them anyway. The crucial thing is that they are softer than your chassis, which is the point everybody seems to be overlooking.

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Right, Dani already did a great job detailing his Droop screws.

Here's the job I did on mine:

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The Avid droop screws I got hold of are 12mm. These can be used front and rear, but the stock sizes are 8mm front and 12mm rear.

At the front with the droop screws all the way in, I set my droop to 124mm each side. (from top of shock to bottom of shock). Out of the box, droop was different from side to side (by 3mm at the front and 2mm at the rear). What can tend to happen is - droop increases as the divot gets bigger.

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Steel grub screws left their mark. At least they were neat little round ones!
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The XTR required the arms to be removed for these Avid titanium droop screws - these did not have hex sockets on the button head side. I don't mind too much, because once fitted, droop adjustment is always made from the top.

The rears were installed and adjusted for 134mm each side. This is where 12mm suddenly seems like a good idea. You need a fair bit more reduction of down travel on the rear shocks on these to attain 134mm.

If the button heads are screwed in all the way as they are on the front, it's actually the piston inside the shock acting as the down stop, not the droop screw.

IMG_20220913_184202.jpg


After a good blast around on grass today, I'm very happy to report it handles superbly well. I'd recommend those droop settings if you like aggressive off-power steering and yet controllable on power.

I had consistent handling, no rollovers and sensible, accurate lines that even my XT8 would have proud of.

General mud and crud was kept at bay by the dusty motors shroud (highly recommended) and POS mud guards (agricultural but do a great job). If anyone wonders why my kit looks clean, this is why.

That and the fact I insist my wife polishes it for me every day. 😜

PS. Please don't tell my wife I said that last part - she'll burn all my RC's! 🤣
 
For anyone wanting to hone their geometry and see what the pros are doing, check out:

Sodialed.com

Here's a great break down of droop settings from sodialed - front, rear, more, less - all covered.

"Less droop

  • Faster steering response
  • Fewer traction rolls
  • Generally suitable for smooth tracks
More droop

  • Slower steering response
  • Better handling over bumps
  • Better jump landings
Less front droop

  • Less weight transfer to the rear during acceleration
  • Less on-power steering
  • More high-speed steering stability
More front droop

  • More weight transfer to the rear during acceleration
  • More on-power steering
  • Less high-speed steering stability
Less rear droop

  • Less weight transfer to front during braking
  • Less stability over bumps
  • More stability under braking
More rear droop

  • More weight transfer to front during braking
  • Better handling over bumps
  • Less stability under braking"
 
Horatio said:
For anyone wanting to hone their geometry and see what the pros are doing, check out:

Sodialed.com

Here's a great break down of droop settings from sodialed - front, rear, more, less - all covered.

"Less droop

  • Faster steering response
  • Fewer traction rolls
  • Generally suitable for smooth tracks
More droop

  • Slower steering response
  • Better handling over bumps
  • Better jump landings
Less front droop

  • Less weight transfer to the rear during acceleration
  • Less on-power steering
  • More high-speed steering stability
More front droop

  • More weight transfer to the rear during acceleration
  • More on-power steering
  • Less high-speed steering stability
Less rear droop

  • Less weight transfer to front during braking
  • Less stability over bumps
  • More stability under braking
More rear droop

  • More weight transfer to front during braking
  • Better handling over bumps
  • Less stability under braking"
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Interesting. I'd love to get into racing but sadly RC is not popular where I live.
For my bashers I just set close to maximum droop to get more suspension travel on landings.
 
DaniC said:
Interesting. I'd love to get into racing but sadly RC is not popular where I live.
For my bashers I just set close to maximum droop to get more suspension travel on landings.
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Getting to know how changes to geometry alter the handling is really good to get to grips with. For racing, it's not possible to be competitive without knowing all about setups or having a pitman that does it all for you..

For casual use or bashing, it's still really useful to know - the truck is very adjustable and getting it tamed makes it easier to drive fast. It's increasingly more fun to drive when it spends less time on it's lid.

The servo saver spring, the droop, tyres, diff fluids, shock oils etc etc - all just as beneficial for backyard bashers as full on racers. It's half the fun of it! 😁

The Kronos XTR is 100% a truck that could be raced. In fact I'd love to see a monster truggy class for Kraton, Kronos, Revo etc - I'd sign up for it.....if it were within 100 miles of where I live.

In the meantime, I love the fact that the Kronos can be run increasingly more predictably with tweaks to geometry and tuning parts that make it less likely to spontaneously combust. 🤣😎
 
DaniC said:
Hi guys,

I recently took the front and rear gearbox and shock towers off the chassis and noticed that the droop screws have created engraved marks on the chassis as seen on the pictures below and I'm wondering if with time this will eventually puncture through the chassis?
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Is this something I should worry about? I'm not sure what can be done about this.... perhaps a locking nut at the end of the droop screw so that it creates a bigger contact surface against the chassis. Maybe there's nothing to worry about...?
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I
DaniC said:
Wow nice comprehensive list of possible solutions! Thanks for taking the time to ask around and put it together!
I did think about number 1 but I felt that whatever I put there would fall very quickly.
Click to expand...
I glued rubber tip on my ears to keep that from happening. So far so good. No damage done to ears on chassis
 
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