RCCrawler Forums

krapulax · 03-07-2009, 11:17 PM

If anyone has some good tips, I would really like to hear them. Personal experience preferred though.

I have replaced my CR01 suspension with Losi long travel shocks and springs, and I was hoping to get rid of the torque twist without resorting to swaybars which limit the car's possibilities in some ways. I tried swaybars, with the new setup, and they work, so you needn't convince me of that.

Using thicker oil helps up to a point but it too becomes a double edged sword when the oil is too thick to allow the shock to rebound. Strong torque twist then tends to work in an accumulating way twisting the chassis a bit more at every move but not letting it come back when under no load. This is the point where the weight of your rig is no longer enough to compress the right front shock back. And there's more to the story. But I will stop here and wait for your input.

One thing I would like to point out is that I would like to stick as much as possible with the kit as it is if possible. I know I have burnt this originality somewhat by getting rid of the cantilever suspension, but this really improved the suspension and I don't see it as a major departure from originality.

One more thing, I have the aluminium bent suspension arms from Tamiya as well and the steel driveshafts.

bonesaw · 03-08-2009, 04:46 AM

BUY A 2ND SET OF SPRINGS DIRECTLY FROM TAMIYA AND DOUBLE THE SPRIGS AT EACH CORNER (EX: OE MEDIUM AND ONE SOFT PER CORNER)

krapulax · 03-08-2009, 08:10 AM

I forgot to mention, I no longer use the tamiya springs, but instead use the springs that came with the shocks (Losi, white springs, I am not sure of the rate).

The problem with having harder springs (or high preload, because you can preload the springs quite a lot on these shocks because they are threaded all the way) is that the ride height of the car is changed and droop diminishes accordingly. At the moment I have resorted to unwinding the spring tensioner fully so the springs have no preaload (or a minimum of load) at maximum suspension travel. This has demonstrated to be the best setup to climbing a ledge I have in the house ( a sort of testing ground) where too much spring preload makes the car incapable of climbing because it's too bouncy and flips backwards. With low viscosity oil and soft springs (i.e. no preload) it climbs very nicely over the ledge. One mention, the ledge is exactly the height that would "hang" the car on the bottom of the center plate, but taken at an agle, it can be climbed. Hard springs will change the posture of the car when the front wheels are just over the ledge enough that the car will roll backwards. In the field, the difference is obvious too. The car is much more competent with no spring preload and droop about 1/4 of suspension travel. With preload enough to counter torque twist there is no droop left in the suspension.

metalry101 · 03-08-2009, 09:53 AM

You might try Losi's stiffer springs. The white springs are the softest they make, so it shouldn't take much to make a difference.

As for your concerns about ride height, I know what you mean, I like my trucks to sit low...luckily the stiffer springs are about a 1/4" shorter than the super soft whites and soft yellows springs. I would think you should able to find some springs that'll help out the torque twist w/o raising the ride height and messing with the way it drives too much.

Other than that, I suppose you could try some internal springs. I believe they'd help reduce your torque twist as well.

EeePee · 03-08-2009, 01:58 PM

Put your rear upper links on top of the link mount.

You can also go a little further and put a spacer underneath the links.

This should help.

dR. hOOK · 03-08-2009, 09:30 PM

Quote:

Originally Posted by EeePee

Put your rear upper links on top of the link mount.

You can also go a little further and put a spacer underneath the links.

This should help.

Have you tried triangulating the lowers on the CR01? Because I heard doing that helps reduce torque twist because I'm tempted on doing that to mine & see how it will perform.

krapulax · 03-08-2009, 09:58 PM

Quote:

Originally Posted by metalry101

You might try Losi's stiffer springs. The white springs are the softest they make, so it shouldn't take much to make a difference.

As for your concerns about ride height, I know what you mean, I like my trucks to sit low...luckily the stiffer springs are about a 1/4" shorter than the super soft whites and soft yellows springs. I would think you should able to find some springs that'll help out the torque twist w/o raising the ride height and messing with the way it drives too much.

Other than that, I suppose you could try some internal springs. I believe they'd help reduce your torque twist as well.

Absolutely. And since the CR01 doesn't have the best of weight placement for a low COG you can use anything to make it sit as low as possible. With my fairly basic mods, the car has the longest suspension travel (it actually uses the entire Losi shock travel from fully compressed where the servo just touches the battery tray to the full extended position where it still applies a bit of weight on the wheels at full droop (this is to keep some traction even at minimum load on the respective wheels).

Can't put the rear links on the top of the servo plate. This would change the axle assembly position such that the lower bent arms (Tamiya upgrade) would hit the lower shock mount and would limit downward suspension travel. For the same reason I had to take the front link spacers too. The link is still on top of the servo plate, but with no spacers. One way to circumvent this would be to extend the links to tilt the axle assembly backwards (for the rear) or forwards (for the front) to keep the lower links from hanging on the lower suspension mount. The unknown here is that I already have slightly negative caster on the front axle, so it will get even more negative whereas on the rear it will become more positive. I am not sure then how this will affect the handling. At the moment turning radius is a joke, you need to go around Australia to turn around or do like an eleven point turn (no dig or rear steering, but I am looking at rear steering especially since I have another two or six channels available in the radio). And no, there is no problem with the steering, it turns fully lock to lock thanks to the animalic torque of the servo.

But I think this is the right track. I think the answer I am looking for is somewhere in the geometry of the suspension, not in shock oil or spring/spring rates (I would like though to try some dual rate springs if I can think of something or I found something available off the shelf) because I am very happy with the hardness of the suspension and the ratio between droop and full travel. I think I have maximised the car's potential there. Any improvement here would have to preserve this and change just the way load is applied at different situations (e.g. car climbing on ledges and such). I just need to find a way to gain some caster back after changing the links' attaching points. I think I need some adjustable turnbuckles to experiment with instead of the fixed length links.

krapulax · 03-08-2009, 11:52 PM

I think too the answer I am looking for is in the link geometry. Playing with springs/shock oil can only get you so far and I am quite happy with the droop/suspension travel settings at the moment. I would like to try some dual rate springs or some dual spring arrangement. I have some ideas to try and I'll report when I get round to it.

Back to links though, changing the attachment point changes the caster and I think I already have negative caster on the front because I had to take the spacer off from under the top links to avoid the bottom links fouling on the lower shock mount. This has changed the caster. Likewise on the rear, I had to move the links at the bottom for the same reason. I think I mentioned this, I have the bent lower arms from Tamiya which took some fiddling to get on the car. The upper links are at the moment adjustable turnbuckles so I can play with them a bit.

drcooper · 03-09-2009, 07:52 AM

my rig has the stock setup drooped, with eeepee's mod. No sway bars anymore, and no torque twist!

krapulax · 03-09-2009, 10:04 AM

I am sure that works, but the tamiya shocks limit the suspension travel. The losi shocks allow about half an inch of extra travel. Otherwise, it's true, I think it's a good idea. Now one more thing, I have an 85 turn motor. i suppose if I went to a "normal" motor I would have more torque twist. At the moment is not that bad, but I would like to be able to attack ledges at whatever angle not just with the front left. Same with driving across a sloped wall.

dR. hOOK · 03-09-2009, 04:26 PM

Well that in mind, I'm gonna try EeePee's mod.

EeePee · 03-09-2009, 06:23 PM

It's basic link geometry 101.

And triangulating the lowers is more about axle steer than torque twist.

dR. hOOK · 03-09-2009, 07:51 PM

Quote:

Originally Posted by EeePee

It's basic link geometry 101.

And triangulating the lowers is more about axle steer than torque twist.

So why are guys with AX10's triangulating their lowers if they say it combats torque twist? Plus, here are a couple of my pics of my setup with losi shocks I just want your advise of my rear setup to show you if it's good or bad.

http://i461.photobucket.com/albums/q...s/IMG_0126.jpg
http://i461.photobucket.com/albums/q...s/IMG_0124.jpg

drcooper · 03-10-2009, 02:53 PM

imo the suspension travel is quite good, u don't need 90 degrees! And the cr01 châssis is a semi scale rig... How high do you lift your wheel? I've tried a 85t, no wheel speed... Went to a 55t, a 45t, and now waiting for my revolver.

dR. hOOK · 03-11-2009, 12:10 AM

Quote:

Originally Posted by drcooper

imo the suspension travel is quite good, u don't need 90 degrees! And the cr01 châssis is a semi scale rig... How high do you lift your wheel? I've tried a 85t, no wheel speed... Went to a 55t, a 45t, and now waiting for my revolver.

My axles would articulate about 30-40 degrees with the losi shocks. It's set up like the stock suspension except I replaced it with coil over shocks.

What size pinion are you running?

krapulax · 03-11-2009, 06:41 AM

Quote:

Originally Posted by drcooper

imo the suspension travel is quite good, u don't need 90 degrees! And the cr01 châssis is a semi scale rig... How high do you lift your wheel? I've tried a 85t, no wheel speed... Went to a 55t, a 45t, and now waiting for my revolver.

As you climb the car faces resistance so the torque is twisting the axle instead of pushing the car.

drcooper · 03-16-2009, 12:58 PM

I used stock pinion before going with a r2d...

krapulax · 03-17-2009, 06:44 PM

The test is to see if the car is now behaving the same if a climb is approached with the right front wheel and the left. A ledge is the best test to show any torque twist left.

I carried out a test recently, by removing the front springs altogether, and changing the front lower shock mount to a custom made aluminium bit (but this was just to solve the problem of the bent link hanging the suspension on the original shock mount). I also attached swaybars to both ends to help trasfer some weight left to right on sideslopes and control weightshift.

All this helped some, but torque twist still acts as the car fights resistance.

I will try to rebuild the shocks with different rebound settings such that the front right tends to stay compressed and the left rear fully extended while the other two will be neutral.

drcooper · 03-18-2009, 11:56 AM

This is how my rig reacts...

http://s43.photobucket.com/albums/e3...t=MOV04087.flv

Muddydan · 03-18-2009, 02:10 PM

Tork twist was a big problem for me and I decided to only change the stock 40 wt shock oil to 70 wt shock oil and that lessened the twist by about 75%.

03-07-2009, 11:17 PM	#1
krapulax Rock Stacker Join Date: Dec 2008 Location: Australia Posts: 82	CR01 torque twist If anyone has some good tips, I would really like to hear them. Personal experience preferred though. I have replaced my CR01 suspension with Losi long travel shocks and springs, and I was hoping to get rid of the torque twist without resorting to swaybars which limit the car's possibilities in some ways. I tried swaybars, with the new setup, and they work, so you needn't convince me of that. Using thicker oil helps up to a point but it too becomes a double edged sword when the oil is too thick to allow the shock to rebound. Strong torque twist then tends to work in an accumulating way twisting the chassis a bit more at every move but not letting it come back when under no load. This is the point where the weight of your rig is no longer enough to compress the right front shock back. And there's more to the story. But I will stop here and wait for your input. One thing I would like to point out is that I would like to stick as much as possible with the kit as it is if possible. I know I have burnt this originality somewhat by getting rid of the cantilever suspension, but this really improved the suspension and I don't see it as a major departure from originality. One more thing, I have the aluminium bent suspension arms from Tamiya as well and the steel driveshafts.

03-08-2009, 08:10 AM	#3
krapulax Rock Stacker Join Date: Dec 2008 Location: Australia Posts: 82	I forgot to mention, I no longer use the tamiya springs, but instead use the springs that came with the shocks (Losi, white springs, I am not sure of the rate). The problem with having harder springs (or high preload, because you can preload the springs quite a lot on these shocks because they are threaded all the way) is that the ride height of the car is changed and droop diminishes accordingly. At the moment I have resorted to unwinding the spring tensioner fully so the springs have no preaload (or a minimum of load) at maximum suspension travel. This has demonstrated to be the best setup to climbing a ledge I have in the house ( a sort of testing ground) where too much spring preload makes the car incapable of climbing because it's too bouncy and flips backwards. With low viscosity oil and soft springs (i.e. no preload) it climbs very nicely over the ledge. One mention, the ledge is exactly the height that would "hang" the car on the bottom of the center plate, but taken at an agle, it can be climbed. Hard springs will change the posture of the car when the front wheels are just over the ledge enough that the car will roll backwards. In the field, the difference is obvious too. The car is much more competent with no spring preload and droop about 1/4 of suspension travel. With preload enough to counter torque twist there is no droop left in the suspension. Last edited by krapulax; 03-18-2009 at 09:58 AM.

03-08-2009, 11:52 PM	#8
krapulax Rock Stacker Join Date: Dec 2008 Location: Australia Posts: 82	I think too the answer I am looking for is in the link geometry. Playing with springs/shock oil can only get you so far and I am quite happy with the droop/suspension travel settings at the moment. I would like to try some dual rate springs or some dual spring arrangement. I have some ideas to try and I'll report when I get round to it. Back to links though, changing the attachment point changes the caster and I think I already have negative caster on the front because I had to take the spacer off from under the top links to avoid the bottom links fouling on the lower shock mount. This has changed the caster. Likewise on the rear, I had to move the links at the bottom for the same reason. I think I mentioned this, I have the bent lower arms from Tamiya which took some fiddling to get on the car. The upper links are at the moment adjustable turnbuckles so I can play with them a bit. Last edited by krapulax; 03-09-2009 at 12:13 AM.

03-08-2009, 04:46 AM	#2
bonesaw Newbie Join Date: Jun 2008 Location: Tulsa Posts: 46	BUY A 2ND SET OF SPRINGS DIRECTLY FROM TAMIYA AND DOUBLE THE SPRIGS AT EACH CORNER (EX: OE MEDIUM AND ONE SOFT PER CORNER)

03-08-2009, 09:53 AM	#4
metalry101 Quarry Creeper Join Date: Sep 2005 Location: Sandy, UT Posts: 368	You might try Losi's stiffer springs. The white springs are the softest they make, so it shouldn't take much to make a difference. As for your concerns about ride height, I know what you mean, I like my trucks to sit low...luckily the stiffer springs are about a 1/4" shorter than the super soft whites and soft yellows springs. I would think you should able to find some springs that'll help out the torque twist w/o raising the ride height and messing with the way it drives too much. Other than that, I suppose you could try some internal springs. I believe they'd help reduce your torque twist as well.

03-08-2009, 01:58 PM	#5
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	Put your rear upper links on top of the link mount. You can also go a little further and put a spacer underneath the links. This should help.

03-09-2009, 07:52 AM	#9
drcooper Pebble Pounder Join Date: Feb 2006 Location: FRANCE Posts: 141	my rig has the stock setup drooped, with eeepee's mod. No sway bars anymore, and no torque twist!

03-09-2009, 10:04 AM	#10
krapulax Rock Stacker Join Date: Dec 2008 Location: Australia Posts: 82	I am sure that works, but the tamiya shocks limit the suspension travel. The losi shocks allow about half an inch of extra travel. Otherwise, it's true, I think it's a good idea. Now one more thing, I have an 85 turn motor. i suppose if I went to a "normal" motor I would have more torque twist. At the moment is not that bad, but I would like to be able to attack ledges at whatever angle not just with the front left. Same with driving across a sloped wall.

03-09-2009, 04:26 PM	#11
dR. hOOK Rock Stacker Join Date: Jan 2009 Location: Winnipeg, Mb Posts: 84	Well that in mind, I'm gonna try EeePee's mod.

03-09-2009, 06:23 PM	#12
EeePee MODERATOR™ Join Date: Jul 2004 Location: Ohio Posts: 18,928	It's basic link geometry 101. And triangulating the lowers is more about axle steer than torque twist.

03-10-2009, 02:53 PM	#14
drcooper Pebble Pounder Join Date: Feb 2006 Location: FRANCE Posts: 141	imo the suspension travel is quite good, u don't need 90 degrees! And the cr01 châssis is a semi scale rig... How high do you lift your wheel? I've tried a 85t, no wheel speed... Went to a 55t, a 45t, and now waiting for my revolver.

03-16-2009, 12:58 PM	#17
drcooper Pebble Pounder Join Date: Feb 2006 Location: FRANCE Posts: 141	I used stock pinion before going with a r2d...

03-17-2009, 06:44 PM	#18
krapulax Rock Stacker Join Date: Dec 2008 Location: Australia Posts: 82	The test is to see if the car is now behaving the same if a climb is approached with the right front wheel and the left. A ledge is the best test to show any torque twist left. I carried out a test recently, by removing the front springs altogether, and changing the front lower shock mount to a custom made aluminium bit (but this was just to solve the problem of the bent link hanging the suspension on the original shock mount). I also attached swaybars to both ends to help trasfer some weight left to right on sideslopes and control weightshift. All this helped some, but torque twist still acts as the car fights resistance. I will try to rebuild the shocks with different rebound settings such that the front right tends to stay compressed and the left rear fully extended while the other two will be neutral.

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03-18-2009, 11:56 AM	#19
drcooper Pebble Pounder Join Date: Feb 2006 Location: FRANCE Posts: 141	This is how my rig reacts... http://s43.photobucket.com/albums/e3...t=MOV04087.flv

03-18-2009, 02:10 PM	#20
Muddydan Newbie Join Date: Mar 2009 Location: Belmont Posts: 11	Tork twist was a big problem for me and I decided to only change the stock 40 wt shock oil to 70 wt shock oil and that lessened the twist by about 75%.

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