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Serpent X20

Old 10-15-2020, 04:02 PM
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Why would you like to update to the new knuckles? What is the missing purpose of the x20 ones?
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Old 10-16-2020, 08:52 AM
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Originally Posted by Airwave View Post
Why would you like to update to the new knuckles? What is the missing purpose of the x20 ones?
the new knuckles has more adjustments on them. Take a close look at the new ones.
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Old 10-16-2020, 03:05 PM
  #498  
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Originally Posted by Airwave View Post
Why would you like to update to the new knuckles? What is the missing purpose of the x20 ones?
Following up on what Brian said, there are two significant adjustments that can be made with the hubs...

Axle Height: by flipping the aluminum axle carrier, you have 1mm of height difference that you can play with. Similar to how the latest off road buggies can adjust hub height, this specifically adjusts the height of the axle on the hub. Adjusting for asphalt vs. carpet will be interesting with this.

Roll Center: by placing shims to adjust the height of the upper pillow ball, you now have the same ability to “shim” the upper arm at the outWe link, changing the roll center. This gives the car an adjustment similar to any other that uses a C-hub/camber link setup, where you would just shim the pívot ball up or down to alter RC.

The other thing I saw mentioned about it is that with the change to a carbon steering arm, the old ones tend to weaken, especially after taking some hits, causing unwanted flex, so the carbon resolves that issue. So all in all, some pretty innovative approaches to solving those technical issues.
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Old 10-16-2020, 05:04 PM
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Originally Posted by TurnNBurn View Post
Following up on what Brian said, there are two significant adjustments that can be made with the hubs...

Axle Height: by flipping the aluminum axle carrier, you have 1mm of height difference that you can play with. Similar to how the latest off road buggies can adjust hub height, this specifically adjusts the height of the axle on the hub. Adjusting for asphalt vs. carpet will be interesting with this.

Roll Center: by placing shims to adjust the height of the upper pillow ball, you now have the same ability to “shim” the upper arm at the outWe link, changing the roll center. This gives the car an adjustment similar to any other that uses a C-hub/camber link setup, where you would just shim the pívot ball up or down to alter RC.

The other thing I saw mentioned about it is that with the change to a carbon steering arm, the old ones tend to weaken, especially after taking some hits, causing unwanted flex, so the carbon resolves that issue. So all in all, some pretty innovative approaches to solving those technical issues.
Very well said and I agree totally. this might be the missing gap needed for pivot ball and C hub cars.
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Old 10-17-2020, 03:51 AM
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I totally understand that you can shim it every way you want but why?
What does changing the height of the axle bring?
Shimming the upper pillow ball is ok, but you can achieve the same result with the inner side... And what about the width? We can already change the distance of the pillow ball and the hex...

From me they only miss a good opportunity. Providing different top parts so you can change the king pin.
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Old 10-17-2020, 08:28 AM
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In off-road applications, when you lower the height of the axle relative to the hub/arm, you gain initial grip into a turn, and a little less exiting. Raising the axle relative to the hub/arm gives you less initial turn in, but more grip exiting a turn. Granted, you’re not dealing with off-road surfaces, so there’s no need for the 4-5mm of variance that off-road buggies can adjust, so 1mm of adjustment is probably what the team/engineers decided on. That being said, the design allows them to produce an axle spacer with 0, .5 or 1.5mm offset later on if they find it offers an advantage. As for the width adjustment - getting a quick and exact 1mm increase/decrease on each side without worrying about whether you’ve altered your camber and without having to take out the calipers to ensure you have the same adjustment on both sides? Priceless... They’ve basically eliminated one of the burdens of going with the pillow ball suspension.

With regard to the RC adjustment, you are correct - AFAIK, it technically doesn’t matter whether you make the adjustment to the inner or outer link - HOWEVER, it may be a matter of how precise the change is. Perhaps the outer adjustment is less of a change than the inner, 1mm adjustments available on the inner hinge. We’ll have to see if anyone shares any tuning tips when it releases.

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Old 10-17-2020, 09:01 AM
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Originally Posted by TurnNBurn View Post
In off-road applications, when you lower the height of the axle relative to the hub/arm, you gain initial grip into a turn, and a little less exiting. Raising the axle relative to the hub/arm gives you less initial turn in, but more grip exiting a turn. Granted, you’re not dealing with off-road surfaces, so there’s no need for the 4-5mm of variance that off-road buggies can adjust, so 1mm of adjustment is probably what the team/engineers decided on. That being said, the design allows them to produce an axle spacer with 0, .5 or 1.5mm offset later on if they find it offers an advantage. As for the width adjustment - getting a quick and exact 1mm increase/decrease on each side without worrying about whether you’ve altered your camber and without having to take out the calipers to ensure you have the same adjustment on both sides? Priceless... They’ve basically eliminated one of the burdens of going with the pillow ball suspension.

With regard to the RC adjustment, you are correct - AFAIK, it technically doesn’t matter whether you make the adjustment to the inner or outer link - HOWEVER, it may be a matter of how precise the change is. Perhaps the outer adjustment is less of a change than the inner, 1mm adjustments available on the inner hinge. We’ll have to see if anyone shares any tuning tips when it releases.
the ARC R12's axle height is also adjustable i played with it and ended back up to stock setting ,
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Old 10-29-2020, 01:11 PM
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Going through the manuals there is quite a few different. Not worth getting all the parts so new car will be here tomorrow. So I have a X20 that I just got together and ran once for sale. Here is a list I came up with so far.

Chassis
RR diff
Front diff
Rear driveshafts
Front driveshafts
Motor mount
Front hubs
Body mounts
Bumper
Rear, upper suspension brackets
Servo mount
Steering posts
Top deck
Standoff stiffeners

Just ran the numbers. Took all the new parts (new to the 21 version) So to buy these parts and upgrade your X20 to a 21 is $650. 18. Kind of a no brainer.

Last edited by Rick Worth; 10-29-2020 at 01:37 PM.
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Old 10-29-2020, 01:58 PM
  #504  
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I think that there are some parts that can carryover to the new car without buying absolutely everything - the big deal-breakers would be the BB driveshaft assemblies, which are super expensive. I’ve already begun performing some changes on my car.

The first step was to remove the lower spacers on the shocks at all four corners (replacing the M3x12 grub screws with M3x8’s), and I also updated the battery mounts, whose parts were actually carryover from the X20 FWD. Next up will be the “+4” inner suspension mounts for the rear, which will also require extending the rear roll bar links an extra .5mm to 4.5mm. On order are the motor mount, which based on the holes looks like it will be a direct fit. The front hubs will also be a direct fit, as will the front bumper assembly - which needs to be wholesale, because the holes for the top plate and body mounts align slightly differently. You definitely want that for the frontal impact support.

The only real question mark is the servo mount, which if it fits on the existing chassis, will allow for installation of the upper deck as well, complete with the standoffs/bearing. I think it will fit, but would mean fastening it with one less screw; the alignment pin on the existing mount is now another countersunk hole on the new chassis for a third screw on the new servo mount.

So, if you exclude the drivetrain changes, I think that the chassis can be upgraded at nominal cost, while reaping the benefits of many of the updates to the new car. I decided that I’m going to try and get my car ready for the Miami Grand Prix’s exhibition 190mm TC class, so I guess we shall soon see how it goes.

Last edited by TurnNBurn; 10-29-2020 at 02:17 PM.
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Old 10-29-2020, 03:39 PM
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Originally Posted by TurnNBurn View Post
The first step was to remove the lower spacers on the shocks at all four corners (replacing the M3x12 grub screws with M3x8’s)
What? Why?
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Old 10-29-2020, 05:45 PM
  #506  
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Originally Posted by Airwave View Post
What? Why?
Don’t ask me, but it’s in the ‘21 manual. The original X20 used M3x12 grubscrews on the lower arms to mount the lower shock ball joints to. While the rears used a 3x6x2mm aluminum spacer behind the lower shock ball, the fronts do not. This made it tough to tighten, as the grub screw pushes the wrench out while you tighten - I had to buy/install spacers to place behind the lower front mounts myself to tighten them properly.

In the ‘21, the grub screws are now M3x8, and spacers do not get installed between the arm and lower shock mount anymore. With the shorter grub screw, you can lock down no problem, and to be honest, it felt really good after I made that change.
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Old 10-30-2020, 09:01 AM
  #507  
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Originally Posted by TurnNBurn View Post
Don’t ask me, but it’s in the ‘21 manual. The original X20 used M3x12 grubscrews on the lower arms to mount the lower shock ball joints to. While the rears used a 3x6x2mm aluminum spacer behind the lower shock ball, the fronts do not. This made it tough to tighten, as the grub screw pushes the wrench out while you tighten - I had to buy/install spacers to place behind the lower front mounts myself to tighten them properly.

In the ‘21, the grub screws are now M3x8, and spacers do not get installed between the arm and lower shock mount anymore. With the shorter grub screw, you can lock down no problem, and to be honest, it felt really good after I made that change.
The shocks and the spacing are based on a 2 dimensional theory. Easiest way to to think about it is to imagine its the same as when you move your shock up and down the shock tower holes and how you change the shock angle. Now look at it from the side and and picture the shock angle and if its angled in or out from the shock tower. Here is a good description on the whole theory of the topic, although a different car, it still applies.
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Old 12-15-2020, 02:13 PM
  #508  
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Default Serpent X20 Gen 1

Wow I had to dig this thread out pretty deep. lol
Well with all the talk about the new X20'21 on FB I thought I would post up some info on my X20. It had it 1 year birthday about 2 weeks ago. lol
I have been testing and trying a few things but always have gone back to my setup. Our outdoor track has very good traction so normally a carpet setup works great on our track. One thing I have noticed with mid motor cars especially the X20 is sensitive to flex adjustment. I also run a standard platform mid motor car and it applies to it also. It seems like these days the only changes I make during the day is chassis flex and track width.
Has that been anyone else conclusion?
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Old 12-16-2020, 10:08 AM
  #509  
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Having run my converted X20 this past weekend, I can’t say much about the flex characteristics, as I had really didn’t really mess with the base “floating” post configuration. My setup changes were pretty much kept to removing the 1mm spacers under the inner suspension mounts up front, going stiffer on the springs up front, softening the rear roll bar, and increasing the droop to just 1mm up from the chassis in the rear (aside from camber-toe changes to complement all those other changes); all were suggestions from the Serpent drivers I met at the event. Overall, my fast lap improved just over two seconds over the course of the weekend as I made each change.

What I can say is that the car was extremely responsive to each change I made (on freshly paved, high-grip asphalt), and with the floating setup, my biggest struggle was maintaining grip in the rear on corner exit. Any time you find your self fixing a loose condition, it’s a MUCH better problem to have than trying to get rid of a push. 🙂 I really liked my first time out with the car. It felt super free and had great rotation entering and going through the corners. Only the exit condition kept me from accelerating more aggressively out of the corners... Well, that and the times I got off-line and into the marbles from the Nitro cars also running at the event.
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Old 12-17-2020, 10:32 AM
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Originally Posted by TurnNBurn View Post
......as I had really didn’t really mess with the base “floating” post configuration.
What is this devil talk you speak of, care to share info and/or pics.
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