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saggcl · 19-05-2012, 14:40:57

CJ

There's no reason for any caster with full hydro as the rams don't care about any small amount of steering input that caster could give. Run it straight-up.

Originally Posted by JRThere's no reason for any caster with full hydro as the rams don't care about any small amount of steering input that caster could give. Run it straight-up.

Is everyone in agreeance? I too need an answer.

Originally Posted by JRThere's no reason for any caster with full hydro as the rams don't care about any small amount of steering input that caster could give. Run it straight-up.One advantage to having rear caster is that you can program some lean of the tires when they are steered. This can make them turn just a bit sharper , and can combat tire roll. This is something alot of people don't consider at all when thinking caster angle. Even with negative caster your front steering can still have good self centering characteristics , but the tires will lean out on corners like a Wino on a bicycle and cause the tires to roll really bad. I have witnessed one case of this that was so bad that on a 44quot; swamper the rim would almost touch the ground when steering while moving on smooth flat ground at road pressure.

Just thought I would throw that into the mix.

I may not be creative enough, but I see no way for a rear hydraulic steering system to be completely proportional to he movement of a joystick without electronics being involved. There are actually quite a few options/ways for this, but expense, and system complexity can quickly go through the roof.

Sean

Originally Posted by CJ LagosI use an orbital with the power beyond port and a hand valve between the seats. The setup is definately bad ass but on my next one I think I'll look harder at a 2nd pump to keep the two systems separate.

Mine definately does not self-center, and it really doesn't bother me. I just turn back and line the tires up by eye. I've gotten good enough with it that I can do this while moving now, at first it took a while. Rear steer is a lot harder than it looks! I very rarely have a problem with the rear tires moving on their own, they hydraulics hold them in place well. My hand valve is open center. If you drive on the road you can tell that the tires bleed off to one side and slowly turn themselves, but I have discovered I can very quickly tap the hand valve even at high speeds to re-adjust. On the trails, you are constantly turning the tires that is never an issue. I have a feeling this quirk stems from the single ended cylinder, my next one will have a double ended on both ends.

I didn't measure caster, I set the pinion angle. I don't think it matters as much because there can't be the return to center with the hand valve.

If I was racing, the self-centering would be more of an issue. I want to put a light on the dash to indicate when they are centered but it just isn't that important to me.

CJ

I have had rear steer for a little over a year now, set up just like this. I agreed with everything you said here. Every time I hear guys talking about thier complex self centering devices I just think quot;why?quot; What a pain in the ass to set up and its just more stuff to fail. If you have the money to spend and you think its necessary, then do it I guess. I'm completely happy with looking at the rear tires to center it. If I'm steering while driving down a trail, I can pretty much get it centered just by feel.

Originally Posted by StationOne advantage to having rear caster is that you can program some lean of the tires when they are steered. This can make them turn just a bit sharper , and can combat tire roll. This is something alot of people don't consider at all when thinking caster angle. Even with negative caster your front steering can still have good self centering characteristics , but the tires will lean out on corners like a Wino on a bicycle and cause the tires to roll really bad. I have witnessed one case of this that was so bad that on a 44quot; swamper the rim would almost touch the ground when steering while moving on smooth flat ground at road pressure.

Just thought I would throw that into the mix.

Sean

From a rock crawling standpoint, it has been discussed to use a lot of positive front caster, like 10 or more deg. The idea being that the front tires flop out and grab more into the rocks on the side when they are turned. On the rear, the same applies only opposite, a lot of negative caster.
I have positive caster on the rear and hate it. On steep up hills, the effective wheel base seems to get shorter when the wheels are turned and makes the car easier to roll ( well, it does for me ).
Hey Sean, I need to talk to you about a rear ram when you have time.

Originally Posted by JRFrom a rock crawling standpoint, it has been discussed to use a lot of positive front caster, like 10 or more deg. The idea being that the front tires flop out and grab more into the rocks on the side when they are turned. On the rear, the same applies only opposite, a lot of negative caster.
I have positive caster on the rear and hate it. On steep up hills, the effective wheel base seems to get shorter when the wheels are turned and makes the car easier to roll ( well, it does for me ).
Hey Sean, I need to talk to you about a rear ram when you have time.

I agree with this logic. I am running (I guess I should say rolling around instead of running ) somewhere around 6* of caster front and rear. Obviously positive in front, and negative in rear. This gives the tires a nice lean into corners which gives the bicycle effect that makes the vehicle steer sharper due to an arc shaped contact patch on the ground. My 120quot; wheelbase buggy ,as it sits, turns ALOT sharper with just front steering than my 95quot; wheelbase , F/R ARB'd TJ does. Mostly due to the awesome steering angle of the mogs , but I do believe the caster helps it out an appreciable ammount.I am always here, just give me a call, or shoot me an e-mail with the best time for me to call you, and I will get with you ASAP. I believe I still have your number here somewhere, so I may give you a call tomorrow evening to see if that works for you.Sean

I definatly agree that some caster in the rear is good, if it was set at 0 deg. it would cause premature wear of linkage. There is always some tolerance of slop in a system so if it is set at zero the wheels will chatter back and forth till it becomes noticable.
It may take a long time to notice this unless you see some speeds once in a while.

Continua en el siguiente

19-05-2012, 14:40:57	#8
saggcl Senior Member Top 1000 Fecha de Ingreso: Oct 2007 Ubicación: Santiago Edad: 46 Mensajes: 3.314	Re: Caster en Rear Steering ??? CJ There's no reason for any caster with full hydro as the rams don't care about any small amount of steering input that caster could give. Run it straight-up. Originally Posted by JRThere's no reason for any caster with full hydro as the rams don't care about any small amount of steering input that caster could give. Run it straight-up. Is everyone in agreeance? I too need an answer. Originally Posted by JRThere's no reason for any caster with full hydro as the rams don't care about any small amount of steering input that caster could give. Run it straight-up.One advantage to having rear caster is that you can program some lean of the tires when they are steered. This can make them turn just a bit sharper , and can combat tire roll. This is something alot of people don't consider at all when thinking caster angle. Even with negative caster your front steering can still have good self centering characteristics , but the tires will lean out on corners like a Wino on a bicycle and cause the tires to roll really bad. I have witnessed one case of this that was so bad that on a 44quot; swamper the rim would almost touch the ground when steering while moving on smooth flat ground at road pressure. Just thought I would throw that into the mix. I may not be creative enough, but I see no way for a rear hydraulic steering system to be completely proportional to he movement of a joystick without electronics being involved. There are actually quite a few options/ways for this, but expense, and system complexity can quickly go through the roof. Sean Originally Posted by CJ LagosI use an orbital with the power beyond port and a hand valve between the seats. The setup is definately bad ass but on my next one I think I'll look harder at a 2nd pump to keep the two systems separate. Mine definately does not self-center, and it really doesn't bother me. I just turn back and line the tires up by eye. I've gotten good enough with it that I can do this while moving now, at first it took a while. Rear steer is a lot harder than it looks! I very rarely have a problem with the rear tires moving on their own, they hydraulics hold them in place well. My hand valve is open center. If you drive on the road you can tell that the tires bleed off to one side and slowly turn themselves, but I have discovered I can very quickly tap the hand valve even at high speeds to re-adjust. On the trails, you are constantly turning the tires that is never an issue. I have a feeling this quirk stems from the single ended cylinder, my next one will have a double ended on both ends. I didn't measure caster, I set the pinion angle. I don't think it matters as much because there can't be the return to center with the hand valve. If I was racing, the self-centering would be more of an issue. I want to put a light on the dash to indicate when they are centered but it just isn't that important to me. CJ I have had rear steer for a little over a year now, set up just like this. I agreed with everything you said here. Every time I hear guys talking about thier complex self centering devices I just think quot;why?quot; What a pain in the ass to set up and its just more stuff to fail. If you have the money to spend and you think its necessary, then do it I guess. I'm completely happy with looking at the rear tires to center it. If I'm steering while driving down a trail, I can pretty much get it centered just by feel. Originally Posted by StationOne advantage to having rear caster is that you can program some lean of the tires when they are steered. This can make them turn just a bit sharper , and can combat tire roll. This is something alot of people don't consider at all when thinking caster angle. Even with negative caster your front steering can still have good self centering characteristics , but the tires will lean out on corners like a Wino on a bicycle and cause the tires to roll really bad. I have witnessed one case of this that was so bad that on a 44quot; swamper the rim would almost touch the ground when steering while moving on smooth flat ground at road pressure. Just thought I would throw that into the mix. Sean From a rock crawling standpoint, it has been discussed to use a lot of positive front caster, like 10 or more deg. The idea being that the front tires flop out and grab more into the rocks on the side when they are turned. On the rear, the same applies only opposite, a lot of negative caster. I have positive caster on the rear and hate it. On steep up hills, the effective wheel base seems to get shorter when the wheels are turned and makes the car easier to roll ( well, it does for me ). Hey Sean, I need to talk to you about a rear ram when you have time. Originally Posted by JRFrom a rock crawling standpoint, it has been discussed to use a lot of positive front caster, like 10 or more deg. The idea being that the front tires flop out and grab more into the rocks on the side when they are turned. On the rear, the same applies only opposite, a lot of negative caster. I have positive caster on the rear and hate it. On steep up hills, the effective wheel base seems to get shorter when the wheels are turned and makes the car easier to roll ( well, it does for me ). Hey Sean, I need to talk to you about a rear ram when you have time. I agree with this logic. I am running (I guess I should say rolling around instead of running ) somewhere around 6* of caster front and rear. Obviously positive in front, and negative in rear. This gives the tires a nice lean into corners which gives the bicycle effect that makes the vehicle steer sharper due to an arc shaped contact patch on the ground. My 120quot; wheelbase buggy ,as it sits, turns ALOT sharper with just front steering than my 95quot; wheelbase , F/R ARB'd TJ does. Mostly due to the awesome steering angle of the mogs , but I do believe the caster helps it out an appreciable ammount.I am always here, just give me a call, or shoot me an e-mail with the best time for me to call you, and I will get with you ASAP. I believe I still have your number here somewhere, so I may give you a call tomorrow evening to see if that works for you.Sean I definatly agree that some caster in the rear is good, if it was set at 0 deg. it would cause premature wear of linkage. There is always some tolerance of slop in a system so if it is set at zero the wheels will chatter back and forth till it becomes noticable. It may take a long time to notice this unless you see some speeds once in a while. Continua en el siguiente