Another set up question…

[PKMSM]

My first RC car is completely wired up and I’m in the process of setting things up.

I am adjusting the servo end point travel range, and I am using the end stop screws as a measure. Essentially I am adjusting the left/right servo end points such that the end stop screws just stop short of touching the hub (using a piece of paper as a measure). With this done, I have different left/right steering endpoints (66 and 57):

I have to point out that with the servo centered, I positioned the servo horn such that it was as parallel as possible with the steering arm (as indicated in the manual), however, in that position my wheels were not pointing straight to the front so I had to use sub-trim to make the wheels straight. I am assuming this is the reason why my left/right endpoint travel ranges are different, but I wanted to verify that I am doing things the right way.

Thanks for the help.

 

[nub]

It's normal. Because of the spline engagement of the horn to the servo it's almost always going to be off some. If you use trim to straighten the wheels you're biasing the ackerman plate to the left or right so the distance to the stops will be different.

You could try zeroing your trim and adjust the steering link to get closer to straight but there's not much room to shorten it if that's the direction you need to go. I wouldn't sweat it though. It's not like it's the life support system on the space shuttle. Your turning radius will be a little bigger in one direction. Have fun with your toy.

Noble FTW

 

[Nicochau]

I never use end stop screws and understand that none of the pro racers does. Check their setup sheets.

I usually use the inner hole on the servo arm. This puts less strain on the servo.

To nub’s point, i focus on centering the ackerman first (servo ON and trim at zero). You do that by increasing steering link length (not much room to shorten it indeed). I then adjust turnbuckles for the right toe out and camber. This way steering trim is minimized, Servo motion range maximized and end points adjustment reasonably close on both sides (but they don’t need to be).

This is probably the one part of the instructions manual that is not great.

 

[PKMSM]

Thank you both, this is very helpful. I agree that with my skills level I’d probably never notice the difference, but I’d still prefer to learn to set things up correctly so I’ll adjust things mechanically as closely as I can before using the trim.

@Nicochau - what’s the reason for not using the endstops?

 

[Nicochau]

Thank you both, this is very helpful. I agree that with my skills level I’d probably never notice the difference, but I’d still prefer to learn to set things up correctly so I’ll adjust things mechanically as closely as I can before using the trim.

@Nicochau - what’s the reason for not using the endstops?

More range of motion. I’ve also noticed the steering range changes significantly based on the position of the suspension arm. Might as well limit any possible binding for the servo.

 

[Kalden]

More range of motion. I’ve also noticed the steering range changes significantly based on the position of the suspension arm. Might as well limit any possible binding for the servo.

Hi, absolutely a nube to racers and bashers. Currently just finishing a very first build ever in this category and observed the same issue with steering throws depending on suspension range.

After much hunting and scratching around I found the hub was interfering with he suspension arms at maximum droop and steering.

I scraped a little bit of plastic from both the hub and arms at the contact points and now the steering throws are consistent with the full range of suspension movement.

 

[Kalden]

About the steering stop screws I can only come to my own conclusion that it's to tighten up the inner wheel steering arm at max throws.

I noticed when at maximum throws the inner wheel's arm due to the extreme geometry creates excessive slop. Backing the screw out until it makes contact with hub IMO allows greater control of the inner wheel instead of it flopping around. Somewhere in the manual says by doing this makes steering more consistent.

I don't have any experience in racing so I cannot verify real life outcomes.

 

[PKMSM]

Hi, absolutely a nube to racers and bashers. Currently just finishing a very first build ever in this category and observed the same issue with steering throws depending on suspension range.

After much hunting and scratching around I found the hub was interfering with he suspension arms at maximum droop and steering.

I scraped a little bit of plastic from both the hub and arms at the contact points and now the steering throws are consistent with the full range of suspension movement.

I adjusted the linkage such that with the servo centered, the ackerman plate was also perfectly centered. I then used a set up tool (Integy set up station) to set up the car in stock form as noted in the book (with the exception of front droop @ 118mm since there is an error in the book). The toe setting required that the linkages be slightly different lengths from left to right, as a result I am still getting different endpoint adjustments on the controller. That said, the car drives straight forever, so I’m not really looking into “fixing” anything. I chalk up the ~1mm difference in length in the linkages to tolerances.

No hub interference in my case at a max droop of 118mm.

 

[Kalden]

I adjusted the linkage such that with the servo centered, the ackerman plate was also perfectly centered. I then used a set up tool (Integy set up station) to set up the car in stock form as noted in the book (with the exception of front droop @ 118mm since there is an error in the book). The toe setting required that the linkages be slightly different lengths from left to right, as a result I am still getting different endpoint adjustments on the controller. That said, the car drives straight forever, so I’m not really looking into “fixing” anything. I chalk up the ~1mm difference in length in the linkages to tolerances.

No hub interference in my case at a max droop of 118mm.

Oh Ok 118mm droop would help with the interference. I wish I knew that earlier I may have avoided the small trimming I had to do

 

[PKMSM]

Oh Ok 118mm droop would help with the interference. I wish I knew that earlier I may have avoided the small trimming I had to do

The max droop I could get on mine was 120mm. Asked the question and the guy from Tekno pointed out the error. He mentioned 118 is max, and the range should be 114-118mm.