RCCrawler Forums

Bart bender · 02-26-2006, 06:16 PM

Quick intro, I am a 33 year old heavy equipment mechanic. twenty years ago I quit racing RC10's and got into 1:1. Off road is my life so it was a no brainer to get back into RC (Crawling this time). Hear is my steering mod. Wanted to stay scale style, because that is the direction I am headed with this Twin eventually.

I like it. The bump steer is minimal and dose not effect the performance. Watcha think?
And yes all of the parts are original parts except the tie rod of coarse.

Robb · 02-26-2006, 06:41 PM

With the normal [lack of] articulation from the stock radius arms, that steering may just work.

If you ever freed up the axle so that it can actually move, I believe that setup would become worthless.

Bart bender · 02-26-2006, 07:46 PM

Well I'll update as soon as my 4 links are done.

rockspider · 02-27-2006, 03:49 AM

I would have liked to keep the steering box, eg.. the steering servo on the frame and going the crossover draglink way, just like I did on my '85 CUCV with ORD crossover.
It could well have worked with the stock arms, as you find yourself.
But the draglink has too steep angle down, and bump steer becomes a problem.
When then I completed the 4-link setup you can see on another thread here, I tried any wknown way to do i, even with straight 4-link plus panhard bar almost parallel to the draglink, and even a lowered "K" draglink double linkage to solve some problems of binding uniball, but no way to completely avoid bump steer. Also when fully artic the draglink setup would not achieve same full steering on both directions, even if working perfectly when standing on flat.
I had to ditch it, due to performance, even if in myt heart I miss its "looking real truck" factor.

Good luck with yours!

MIKEK5 · 03-02-2006, 09:57 AM

Hate to say it but I agree with rockspider. I have the crossover-histeer on my 1:1 89 K5 and would love to have it work on my rc project. The bump steer would still be there or things would bind, either way if you get her figured I'd love to see it.

skipstr71 · 03-03-2006, 12:56 AM

I like it too... I have done a SAS on my yoda and I would like to see it on a RC project, but agree that its gonna cause bump steer and binding.. I bet on a rig without a lot of articulation it may work.. Take a look at the 1:1 custom crawler.. They use a hydro steer not only because its stronger, but it eliminates the conection of axle and steering box by a bar..

My only suggestion is that you use a three link (or something like that) and a pan hard bar that is mounted paralell with the steering shaft. That may have some effect helping fight the bump steer..

rockspider · 03-03-2006, 05:06 AM

Just to better expalin why I had to ditch it.
The best setup I did had 4 parallel links connecting axle to frame, and panhard bar.
The frame mount for the panhard was as low as possible, but consider that you cannot have it protruding much from the frame or it will hit something during compression.
The draglink was perfectly parallel to the panhard, but for many reasons it could not be of the same lenght. More on this later.
With this setup bump steer was almost inexistant really. The problem was that when compressing the suspension, due to the panhard, the axle was moving quite a bit to the right side. Even if I could survive with it, I realized another problem. When artic, due to the panhard, the right wheel could fully compress without problems (panhard actually pushing it farther from the frame), but the left wheel at full compression was just pushed toward the frame, and would have required an unusually big fender cutting to clear.
Also, and here the above mentioned difference in lenght plays, at full right wheel compression, with the panhard up and touching the frame, the draglink become short and go in self steering toward right, so that it would bind the linkage if further steered right, and could not turn the wheels all way left.
After all, these are problems even 1:1 rigs have when artic is so extreme.
I could have done it work properly with less artic, and I plan on doing it properly, but on a more scale 2.2" project truck.

Bart bender · 03-03-2006, 05:38 AM

Believe me my '79 CJ5 has bump steer with a 4" and just 33's. The twin however, and you are all right, after I get the 4 link and more artic it will effect it. I just want to make it work so it will stay scale with as little bump steer as possible. Any one built radius arms on the front? I'm debating on using some 3/8 Al. and tig some mounts on for the radius arms. Also is there anyone designing suspension, coil over, for droop and not compression?

Bart bender · 03-03-2006, 05:45 AM

The Alasken Assasin is my insperation.

rockspider · 03-03-2006, 10:58 AM

Radius arms like a Landy, like the front of an old Bronco you mean?
They all need some sort of built-in flex at the axle mounts, otherwise they're binding badly.
1:1 rigs have rubber mounts for it, but that is way too stiff for a scale model. Also bear in mind that the "poor" artic of a Twin would be considered quite "good flex" for a real 1:1 stock vehicle. Hard to find any more flex from radius arms in a model.
Also radius arms have to counteract the torque from the axle that tries to flex and lift them in acceleration, with big problems at the pinion angle, expecially at the rear.
4-links are much better on this, converting the rotational torque in straight push-pull action on the links.
As a matter of fact, with same motor, same wheelbase, same tires as before, my 4-link conversion now does not wheelie, it just squat on all 4, spins and blasts forward.

Referring to your CJ, bad thing you got bump steer, but with leafs and no panhard it can hardly be corrected.
However, as you know, it's liveable with.
The problem when referring to a scale model is a completely different power to weight ratio. It dosn't matter if you got some bump steer on your rig, when you have learned its behaviour. But you are just slow offroading or running down the interstate at a close-to-law speed limit. Would you happily tolerate the same bump steer in a protruck kind of vehicle with dragster wheeling acceleration and speed in excess of 200Mph? Bet you not.
That's the point. Even small flaws are exaggerated due to the high performances.
For converse, you can live even with major steering mishaps if the model will be a dedicated slow crawler only.

Bart bender · 03-03-2006, 01:54 PM

I haven't got my lathes in yet so I did take it for a couple high speed passes in the back yard chasing the dog and I didn't notice any difference. Like you said you get used to the querks. 4 link goin together this weekend. I'm gonna attempt a square drive shaft too. That'll be interesting.

skipstr71 · 03-03-2006, 02:19 PM

Sounds like you have it figured out..

I have played with square shafts.. First the steel ones that were way to heavy. and now I have the materials to make it outta square brass for the slip.. If you have a lot of power I would go with something other than brass..

maybe some of this... with a universal welded/brazed on..

This was mine.. But it was overkill for this project and I switched to revo shafts.. If the sqare shafts down work then I would think you would be happy with the revos shafts..

Bart bender · 03-06-2006, 11:15 AM

Did a pile of digging this weekend and could not find any ujoints that I liked. Just ordered my Revo shafts this morning. I still want to build my own shafts someday when I find the ujoints I like.

rockspider · 03-06-2006, 12:20 PM

Take a look on www.sdp-si.com (industrial stuff for micromechanical and similar) and see online or free download the Metric Catalog of drive parts, then under paragraph 7, page 10 they have metal driveshaft with sliding splines and u-joints for 8mm bore (perfect fit with Force axles) and on page 19 they have the molded plastic version.
Interesting, uh?

Bart bender · 03-07-2006, 10:52 AM

Oh I likey that. Lots of good schtuff in that catalog. Thanks for the link spider.

skipstr71 · 03-07-2006, 03:29 PM

Quote:

Originally Posted by rockspider

Take a look on www.sdp-si.com (industrial stuff for micromechanical and similar) and see online or free download the Metric Catalog of drive parts, then under paragraph 7, page 10 they have metal driveshaft with sliding splines and u-joints for 8mm bore (perfect fit with Force axles) and on page 19 they have the molded plastic version.
Interesting, uh?

Yea thats a great place.. Kinda pricey but high quality stiff.. Thats where I pulled those pics of the hex shafts from, but I frogot to give the link to them.. but rockspider know whats up...

02-26-2006, 06:16 PM	#1
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	1:1 steering on my Twin Quick intro, I am a 33 year old heavy equipment mechanic. twenty years ago I quit racing RC10's and got into 1:1. Off road is my life so it was a no brainer to get back into RC (Crawling this time). Hear is my steering mod. Wanted to stay scale style, because that is the direction I am headed with this Twin eventually. I like it. The bump steer is minimal and dose not effect the performance. Watcha think? And yes all of the parts are original parts except the tie rod of coarse.

03-03-2006, 10:58 AM	#10
rockspider Quarry Creeper Join Date: Nov 2005 Location: Italy Posts: 262	Radius arms like a Landy, like the front of an old Bronco you mean? They all need some sort of built-in flex at the axle mounts, otherwise they're binding badly. 1:1 rigs have rubber mounts for it, but that is way too stiff for a scale model. Also bear in mind that the "poor" artic of a Twin would be considered quite "good flex" for a real 1:1 stock vehicle. Hard to find any more flex from radius arms in a model. Also radius arms have to counteract the torque from the axle that tries to flex and lift them in acceleration, with big problems at the pinion angle, expecially at the rear. 4-links are much better on this, converting the rotational torque in straight push-pull action on the links. As a matter of fact, with same motor, same wheelbase, same tires as before, my 4-link conversion now does not wheelie, it just squat on all 4, spins and blasts forward. Referring to your CJ, bad thing you got bump steer, but with leafs and no panhard it can hardly be corrected. However, as you know, it's liveable with. The problem when referring to a scale model is a completely different power to weight ratio. It dosn't matter if you got some bump steer on your rig, when you have learned its behaviour. But you are just slow offroading or running down the interstate at a close-to-law speed limit. Would you happily tolerate the same bump steer in a protruck kind of vehicle with dragster wheeling acceleration and speed in excess of 200Mph? Bet you not. That's the point. Even small flaws are exaggerated due to the high performances. For converse, you can live even with major steering mishaps if the model will be a dedicated slow crawler only. Last edited by rockspider; 03-03-2006 at 11:11 AM.

02-26-2006, 06:41 PM	#2
Robb RCC Addict Join Date: Aug 2005 Location: VARCOR Posts: 1,826	With the normal [lack of] articulation from the stock radius arms, that steering may just work. If you ever freed up the axle so that it can actually move, I believe that setup would become worthless.

02-26-2006, 07:46 PM	#3
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	Well I'll update as soon as my 4 links are done.

02-27-2006, 03:49 AM	#4
rockspider Quarry Creeper Join Date: Nov 2005 Location: Italy Posts: 262	I would have liked to keep the steering box, eg.. the steering servo on the frame and going the crossover draglink way, just like I did on my '85 CUCV with ORD crossover. It could well have worked with the stock arms, as you find yourself. But the draglink has too steep angle down, and bump steer becomes a problem. When then I completed the 4-link setup you can see on another thread here, I tried any wknown way to do i, even with straight 4-link plus panhard bar almost parallel to the draglink, and even a lowered "K" draglink double linkage to solve some problems of binding uniball, but no way to completely avoid bump steer. Also when fully artic the draglink setup would not achieve same full steering on both directions, even if working perfectly when standing on flat. I had to ditch it, due to performance, even if in myt heart I miss its "looking real truck" factor. Good luck with yours!

03-02-2006, 09:57 AM	#5
MIKEK5 Newbie Join Date: Nov 2005 Location: BELLINGHAM Posts: 1	Hate to say it but I agree with rockspider. I have the crossover-histeer on my 1:1 89 K5 and would love to have it work on my rc project. The bump steer would still be there or things would bind, either way if you get her figured I'd love to see it.

03-03-2006, 12:56 AM	#6
skipstr71 Rock Crawler Join Date: Mar 2004 Location: BAY AREA Posts: 557	I like it too... I have done a SAS on my yoda and I would like to see it on a RC project, but agree that its gonna cause bump steer and binding.. I bet on a rig without a lot of articulation it may work.. Take a look at the 1:1 custom crawler.. They use a hydro steer not only because its stronger, but it eliminates the conection of axle and steering box by a bar.. My only suggestion is that you use a three link (or something like that) and a pan hard bar that is mounted paralell with the steering shaft. That may have some effect helping fight the bump steer..

03-03-2006, 05:06 AM	#7
rockspider Quarry Creeper Join Date: Nov 2005 Location: Italy Posts: 262	Just to better expalin why I had to ditch it. The best setup I did had 4 parallel links connecting axle to frame, and panhard bar. The frame mount for the panhard was as low as possible, but consider that you cannot have it protruding much from the frame or it will hit something during compression. The draglink was perfectly parallel to the panhard, but for many reasons it could not be of the same lenght. More on this later. With this setup bump steer was almost inexistant really. The problem was that when compressing the suspension, due to the panhard, the axle was moving quite a bit to the right side. Even if I could survive with it, I realized another problem. When artic, due to the panhard, the right wheel could fully compress without problems (panhard actually pushing it farther from the frame), but the left wheel at full compression was just pushed toward the frame, and would have required an unusually big fender cutting to clear. Also, and here the above mentioned difference in lenght plays, at full right wheel compression, with the panhard up and touching the frame, the draglink become short and go in self steering toward right, so that it would bind the linkage if further steered right, and could not turn the wheels all way left. After all, these are problems even 1:1 rigs have when artic is so extreme. I could have done it work properly with less artic, and I plan on doing it properly, but on a more scale 2.2" project truck.

03-03-2006, 05:38 AM	#8
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	Believe me my '79 CJ5 has bump steer with a 4" and just 33's. The twin however, and you are all right, after I get the 4 link and more artic it will effect it. I just want to make it work so it will stay scale with as little bump steer as possible. Any one built radius arms on the front? I'm debating on using some 3/8 Al. and tig some mounts on for the radius arms. Also is there anyone designing suspension, coil over, for droop and not compression?

03-03-2006, 05:45 AM	#9
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	The Alasken Assasin is my insperation.

03-03-2006, 01:54 PM	#11
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	I haven't got my lathes in yet so I did take it for a couple high speed passes in the back yard chasing the dog and I didn't notice any difference. Like you said you get used to the querks. 4 link goin together this weekend. I'm gonna attempt a square drive shaft too. That'll be interesting.

03-03-2006, 02:19 PM	#12
skipstr71 Rock Crawler Join Date: Mar 2004 Location: BAY AREA Posts: 557	Sounds like you have it figured out.. I have played with square shafts.. First the steel ones that were way to heavy. and now I have the materials to make it outta square brass for the slip.. If you have a lot of power I would go with something other than brass.. maybe some of this... with a universal welded/brazed on.. This was mine.. But it was overkill for this project and I switched to revo shafts.. If the sqare shafts down work then I would think you would be happy with the revos shafts..

Sponsored Links

03-06-2006, 11:15 AM	#13
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	Did a pile of digging this weekend and could not find any ujoints that I liked. Just ordered my Revo shafts this morning. I still want to build my own shafts someday when I find the ujoints I like.

03-06-2006, 12:20 PM	#14
rockspider Quarry Creeper Join Date: Nov 2005 Location: Italy Posts: 262	Take a look on www.sdp-si.com (industrial stuff for micromechanical and similar) and see online or free download the Metric Catalog of drive parts, then under paragraph 7, page 10 they have metal driveshaft with sliding splines and u-joints for 8mm bore (perfect fit with Force axles) and on page 19 they have the molded plastic version. Interesting, uh?

03-07-2006, 10:52 AM	#15
Bart bender I wanna be Dave Join Date: Jan 2006 Location: Iowa, the antirecreation state! Posts: 2,227	Oh I likey that. Lots of good schtuff in that catalog. Thanks for the link spider.

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