RC Crawler Steering

[JeremyH]

Originally Posted by 4xFord

Great thread Jeremy! Almost as good as the skittles battle thread.

Oh damn......I need to do that again!


BTW, does anybody think that anything else needs to be added to the first few posts?? Is it missing anything? Is anything incorrect?

[C*H*U*D]

Originally Posted by JeremyH

BTW, does anybody think that anything else needs to be added to the first few posts?? Is it missing anything? Is anything incorrect?

The only thing I'm not crazy about is the picture on the first page showing caster. It would be better if you had a line going vertical through the axle, and then through the kingpin to show the caster angle.

Something like this:




EDIT: I'm talking about the picture of your Super. The picture of the Wraith looks good, but would also benefit from a vertical line so people know what your are measuring off of.

[JeremyH]

Thanks for the input. I will work on a new picture this evening.

Thanks!

[kaneohecrawler]

Originally Posted by JeremyH

Well, waddya know, looks like VP nailed the "correct" Ackermann angle for their Berg knuckle:


This is for the outer hole, the inner hole looks to be a bit less of an angle.

So, for those of you reading, it looks like if you want "correct" Ackermann steering, then your best bet is to run these knuckles.

The same applies for vp's axial knucks as well.. only problem is those are reverse acherman knuckles. Meaning outside turns sharper than inside. For correct steering path we need the inner tire to turn sharper so they acually made them 15* in the wrong direction...the green lines on ur diamgram need to continue all the way to tierod mounting point. Whick will show were they are "supposed" to mount for correct acherman. only problem is that when you go past 0 and even 0 acherman knuckles the tend to rub the inside of the tires pretty bad. At least with the ax style high steer knuckles from what I have found.

Those do work for correct acherman tho when applied in BTA steering setup.

Jeremy this is a very insightful and informative thread. Big ups to you bro

[JeremyH]

Originally Posted by kaneohecrawler

Jeremy this is a very insightful and informative thread. Big ups to you bro

Thanks for the compliments and for giving your input!

Originally Posted by kaneohecrawler

....they acually made them 15* in the wrong direction...the green lines on ur diamgram need to continue all the way to tierod mounting point.
Those do work for correct acherman tho when applied in BTA steering setup.

You are 100% correct! Good call! I had not noticed that earlier....

So, for a "correct ackermann" setup, these VP knuckles need to be run behind the axle.

[Charlie-III]

Originally Posted by JeremyH

BTW, does anybody think that anything else needs to be added to the first few posts?? Is it missing anything? Is anything incorrect?

I added a few comments (post 63)....if you want to use them, fine, if not, fine. It's your thread and it is rather helpful to many on this forum as is.

[JeremyH]

Originally Posted by Charlie-III

It's your thread and it is rather helpful to many on this forum as is.

It has been requested for this to be more than just a thread...

[Charlie-III]

Originally Posted by JeremyH

It has been requested for this to be more than just a thread...

Hey, if you get a "STICKIE"...more power to you!

As I stated before, you are covering things that need to be covered. I'm only "pissed" I didn't beat you to it.

Again, great job.

[dirk379]

Remember this "tech article" about getting more power out of your steering. Not as informative as this thread but still a good one.

RCCrawler.com- Your #1 source for Radio Controlled Rockcrawling!

[West Cork Basher]

Yeah... Stickie this thread . .


Sean
.
..

[JeremyH]

Yeah, I browsed through several of the tech articles before I wrote up the first few posts in this thread. I wanted to get a good format and I wanted to make sure it hadnt been covered before.

BTW, this info will soon be a tech article on the main page. I just wanted to finalize a few things before Jason posted it.

[West Cork Basher]

Originally Posted by JeremyH

Yeah, I browsed through several of the tech articles before I wrote up the first few posts in this thread. I wanted to get a good format and I wanted to make sure it hadnt been covered before.

BTW, this info will soon be a tech article on the main page. I just wanted to finalize a few things before Jason posted it.

Well done to you for all your hard work with lots of great infomation....

[josh6575]

post #84 nailed ackerman. I can't beleive that the only crawler that comes from the factory with a correct acerman set up is the xr-10. All others are not even zero. They are going the wrong direction. When would it ever be a good Idea for the inside wheel to not turn as sharp as the outside wheel. Check out the almost corrected bully ackerman.

[opek]

Originally Posted by josh6575

post #84 nailed ackerman. I can't beleive that the only crawler that comes from the factory with a zero ackerman set up is the xr-10.

FTFY. Although ackerman steering was discussed on the first page, correct ackerman was not explained. Correct ackerman will have no scrub when the a vehicle with an open diff is turning. Here is a picture worth a million words:



Zero ackerman is when both the inside and outside wheel turn the same amount. Reverse ackerman is when the outside wheel turns more than the inside wheel.

[JeremyH]

Originally Posted by C*H*U*D

The only thing I'm not crazy about is the picture on the first page showing caster. It would be better if you had a line going vertical through the axle, and then through the kingpin to show the caster angle.

I updated the first post with a picture like yours....I also added a measurement of the caster on my super.

[JeremyH]

Originally Posted by opek

Although ackerman steering was discussed on the first page, correct ackerman was not explained.

You are correct, I did not think that too many folks actually wanted to see a correct ackermann setup discussed. Do you think it is needed? Maybe just a short description and one of the pictures I posted earlier (which is similar to what you just posted)....

[JeremyH]

Originally Posted by josh6575

post #84 nailed ackerman. I can't beleive that the only crawler that comes from the factory with a correct acerman set up is the xr-10. All others are not even zero. They are going the wrong direction. When would it ever be a good Idea for the inside wheel to not turn as sharp as the outside wheel. Check out the almost corrected bully ackerman.

I agree. Until kaneohecrawler posted, I had not realized that they were going the wrong direction. The only way for them to be correct would be to run BTA with those knuckles (which is precisely what Axial did).

Is that your bully?

[josh6575]

yep

[opek]

This is crazy talk, everything is as described above.

I will go flip my knuckles around if I need to, but I'm 99% sure the ackerman knuckles sold by VP and axial are correct ackerman when mounted in front of the axle and are reverse ackerman when BTA. It's pretty much something I think about every day. You need to run assloads of toe out to achieve reverse ackerman when using ackerman knuckles in a (can i say FAS?) front axle steering setup. You only need a squintch of toe in to achieve the same amount of reverse ackerman when running the same knuckles BTA.

Can anyone else corroborate that?

[JeremyH]

Originally Posted by josh6575

yep

Interesting. Did you notice any changes in scrub when you switched from zero ackermann to your current setup?

Originally Posted by opek

I will go flip my knuckles around if I need to, but I'm 99% sure the ackerman knuckles sold by VP and axial are correct ackerman when mounted in front of the axle and are reverse ackerman when BTA.

Are you talking about the AX10 or the XR10? The AX10 VP knuckles is what I posted in post #56 (and what kaneohecrawler quoted) and those are the "incorrect" ackermann knuckles (unless, of course, you run them BTA).