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Universal Starting Setup - How to.

Old 12-01-2015, 07:25 AM
  #16  
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Originally Posted by My ST-RR EVO
What point are you making with the outdrive photos? They look like they're in really good shape especially for 2 gallons!
Less wear is a by-product of less axle bind, remember I use the parallel arms and axles. Less axle bind means less wasted energy and more efficient drivetrain.
In the TLR 8ight 4.0 the center-front CVD angle was reduced and in the TLR 8ight 3.0 the front CVDs were made parallel with the arms precisely to have less (or in the case of the arms negligible) axle bind to improve drivetrain efficiency and promote neutral driving characteristics.

I can't say I can measure it but my car rolls fairly free (not kyosho free though) but having less outdrive wear can't be bad!

The front has more axle bind, similarly to a TLR 8ight 2.0 and I can't tune it out completely without producing my own uprights, I'll post a photo later to compare both outdrives
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Old 12-01-2015, 07:37 AM
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After wearing out a set of rear outdrives on my D815, I'm anxious to see what effect it'll have on my car with the new set along with new pins. I feel like axle bind is something very little of the non upper echelon racers understand is very real when it comes to feel of the car.
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Old 12-01-2015, 10:49 AM
  #18  
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Originally Posted by Socket
After wearing out a set of rear outdrives on my D815, I'm anxious to see what effect it'll have on my car with the new set along with new pins. I feel like axle bind is something very little of the non upper echelon racers understand is very real when it comes to feel of the car.
That's what made me post a photo of my outdrives, I read you wore out yours after what, a hour and a half? Please report back.
And thank you for giving my method a try. You and My ST-RR Evo have one of the best car to make this alterations because the D815 has adjustable upright height, lower inner roll center bushings and various upright camber plates. While there are too many options on the lower bushings, two bushing positions and another two for hub height would suffice, the camber plates come in very handy.
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Old 12-01-2015, 12:08 PM
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Originally Posted by 30Tooth
That's what made me post a photo of my outdrives, I read you wore out yours after what, a hour and a half? Please report back.
And thank you for giving my method a try. You and My ST-RR Evo have one of the best car to make this alterations because the D815 has adjustable upright height, lower inner roll center bushings and various upright camber plates. While there are too many options on the lower bushings, two bushing positions and another two for hub height would suffice, the camber plates come in very handy.
I wore the center driveline pins out after a weekend of racing at the US open. Friday I had 5, 6 minute practices. Saturday I had 3 7 minute qualifiers, and then sunday I had the 30 minute semi and 1 hour main.

All pins were brand new to start the weekend, at the end, rear outdrives were hammered, and every single pin needs replacement.
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Old 12-01-2015, 01:05 PM
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Originally Posted by Socket
I wore the center driveline pins out after a weekend of racing at the US open. Friday I had 5, 6 minute practices. Saturday I had 3 7 minute qualifiers, and then sunday I had the 30 minute semi and 1 hour main.

All pins were brand new to start the weekend, at the end, rear outdrives were hammered, and every single pin needs replacement.
The rear outdrives being hammered makes sense. You have axle bind both from hub height and arm sweep (commonly known as inboard toe). You didn't mention front diff outdrives but I guess they are fine. I don't own a D815 but from the setup sheet image looks like the front CVDs are swept back, can you confirm this? And can you make them straight with the wheelbase shims?
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Old 12-01-2015, 01:35 PM
  #21  
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From my on-road experience, arm angle and bump steer have a lot of influence on handling. For example, if the arms point downward to the wheels, you get a car that is really responsive on that end. Basically resists rolling, and reach maximum grip on the tires earlier. Good on high bite, but handful on low.
For bump steer, it was a big deal on the Tamiya M03. Those cars had bump-in out of the box, and made it very twitchy. After making it neutral or slight bump-out, it was much easier to drive. I think the same applies to off-road cars too.

I'll setup my D815 race ready and see where my arms/axles line up.
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Old 12-01-2015, 01:44 PM
  #22  
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Originally Posted by Socket
I wore the center driveline pins out after a weekend of racing at the US open. Friday I had 5, 6 minute practices. Saturday I had 3 7 minute qualifiers, and then sunday I had the 30 minute semi and 1 hour main.

All pins were brand new to start the weekend, at the end, rear outdrives were hammered, and every single pin needs replacement.
I use Tamiya anti-wear grease on my outdrives for the past four cars that I've owned, and all of them had minimal wear. This grease if super thick and won't fling out(none on brake disks either). I just dab a tiny bit on the contact points and clean it out after every day of running. Yes, some dirt does get on, but the grease is still there. I'm sure they will slow down the wear process. Try it out if want to
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Old 12-01-2015, 03:03 PM
  #23  
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Originally Posted by inpuressa
From my on-road experience, arm angle and bump steer have a lot of influence on handling. For example, if the arms point downward to the wheels, you get a car that is really responsive on that end. Basically resists rolling, and reach maximum grip on the tires earlier. Good on high bite, but handful on low.
For bump steer, it was a big deal on the Tamiya M03. Those cars had bump-in out of the box, and made it very twitchy. After making it neutral or slight bump-out, it was much easier to drive. I think the same applies to off-road cars too.

I'll setup my D815 race ready and see where my arms/axles line up.
Please do, that car has a lot of rear axle bind (like the MP7.5).

Here's photos of my front outdrives, sorry haven't cleaned the front since last weekend mud fest.
Attached Thumbnails Universal Starting Setup - How to.-img_20151201_221133.jpg   Universal Starting Setup - How to.-img_20151201_221143.jpg  
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Old 12-04-2015, 01:54 AM
  #24  
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Originally Posted by 30Tooth
Less wear is a by-product of less axle bind, remember I use the parallel arms and axles. Less axle bind means less wasted energy and more efficient drivetrain.
In the TLR 8ight 4.0 the center-front CVD angle was reduced and in the TLR 8ight 3.0 the front CVDs were made parallel with the arms precisely to have less (or in the case of the arms negligible) axle bind to improve drivetrain efficiency and promote neutral driving characteristics.

I can't say I can measure it but my car rolls fairly free (not kyosho free though) but having less outdrive wear can't be bad!

The front has more axle bind, similarly to a TLR 8ight 2.0 and I can't tune it out completely without producing my own uprights, I'll post a photo later to compare both outdrives
Wouldn't the pin hitting the one exact spot within the out drive over and over not cause more wear in that one spot in the form of a notch and the rest of the out drive "slot" would remain new? Then again I guess I could see how a pin moving in and out could act like a saw. Usually the rear out drives wear more sooner, then the center out drives and then the fronts. Yes on the D815, the front axles sweep back a little with the"standard" front wheelbase settings.
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Old 12-04-2015, 03:25 AM
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Originally Posted by My ST-RR EVO
Wouldn't the pin hitting the one exact spot within the out drive over and over not cause more wear in that one spot in the form of a notch and the rest of the out drive "slot" would remain new? Then again I guess I could see how a pin moving in and out could act like a saw. Usually the rear out drives wear more sooner, then the center out drives and then the fronts. Yes on the D815, the front axles sweep back a little with the"standard" front wheelbase settings.
Objective: Hypothetical causes of axle bind.
That's a pretty good question, let's think in hypothetical scenarios:
-example #1: zero dogbone plunge/axle bind -when the pin is facing the car longitudinally and we push and pull the suspension up and down the pin doesn't travel in or out of the slot and when the pin is facing the up-down axis the pin angle equals the arm angle- the average place where the pin sits becomes narrower, the pin is under rotational forces from the outdrive slot. When the arm moves the pin angles accordingly, the pin is no further pushed nor pulled.
-example #2: dogbone plunge/axle bind is present: the pin slides in and out with suspension movement. The average place of where the pin sits becomes larger, the pin is under rotational force from the outdrive slot and pull and push forces from the suspension arm. If the axle points downward to the center of the car the pin angle is arm angle plus X angle from the axle, meaning more average angle when the suspension is compressed. If the axle points upward to the center of the car the pin angle is arm angle minus arm angle, meaning less average angle when the suspension is compressed.
In the example with axle bind, the pin is under twisting force and stronger pull and push forces, a saw motion like you said. Therefore rotating the outdrive and applying a push/pull to the axle increases exponentially the axle bind.
Try with an outdrive and dogbone in your hands: dogbone parallel to the outdrive, twist the dogbone and feel the bind, with the outdrive in the same place move the other dogbone end up and down and feel the bind while twisting the dogbone and applying brake to the outdrive. Now lock the outdrive and while twisting the dogbone move it up and down, front and back and in and out the outdrive. Which did you felt the most axle bind?

Thank you for checking it out, can you say if you picked up the rear so the kickup angle becomes zero, the axle angle increases or decreases?

Last edited by 30Tooth; 12-18-2016 at 04:09 PM.
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Old 12-04-2015, 03:38 PM
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Objective: Shorter springs to have less rebound.

Wouldn't shock rebound be affected by spring length?
Bare with me, you have for example a no rebound shock setup, but the spring length you are using causes the shock to always extend to maximum length, meaning you will always have rebound.
Wouldn't be better to run a spring that didn't further mess shock rebound?

Conclusion: I used that on my on road chassis, they aren't supposed to jump so you have the shocks as dead as they can be, short springs included. In my current race cars I can choose to have long shocks or shorter shocks, the longer shocks always provide more stability with everything but shock preload the same, I thought it was because the piston would be further from the bladder but apparently that's an added bonus.
I'm thinking about doing this to the front, I shouldn't do it because I'm using the outer arm hole for shock mounting but unscrewing the rod end would net me the same stroke at the wheel but less spring preload at extension.

Last edited by 30Tooth; 12-18-2016 at 04:11 PM.
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Old 12-05-2015, 01:18 AM
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Great explanation about the out drive wear.

as far as lifting the rear of the car, I'll have to see what effect it has on the front axle angle when I get a chance. Just from visualizing in my head, the axle would always have to have an angle it just would change the direction depending on how you oriented the car.
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Old 12-05-2015, 06:34 AM
  #28  
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Hope it helps, I have other ideas to cut down outdrive wear, they work in tandem with inpuressa ideas

You're right I was thinking the other way. Another thing, how much caster are you using?

Last edited by 30Tooth; 12-05-2015 at 06:59 AM.
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Old 12-05-2015, 07:09 AM
  #29  
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D815 rear bone angle. Running short wheel base.

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Old 12-05-2015, 10:44 AM
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Thank you, if you don't mind could you take a pic of the front axle taken from the side like that pic and another from the front with the arms straight?
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