going with full hydro , have kin pin 60 , wondering what lenght of arms have you guys used for this application. I was told 7.5 " from the center of the kinpin to the center of the hole i got a set of arms but only measure out to be 6.5 would one inch make much diffrence? thks

My wife said 1 more inch would be awsome:flipoff2:

If I remember correctly, the shorter the arm, the more turning angle there will be, the longer the arm, the less...so, tighter turning radius on the shorter arm than the longer arm.

If I remember correctly, the shorter the arm, the more turning angle there will be, the longer the arm, the less...so, tighter turning radius on the shorter arm than the longer arm.

Only if you are limited by the stroke of the ram.

The farther out, the more leverage and the longer it takes to turn the wheel.

Speed difference will be minimal....


:mr-t:

Only if you are limited by the stroke of the ram.

The farther out, the more leverage and the longer it takes to turn the wheel.

Speed difference will be minimal....


:mr-t:

I don't think so. If the ram is exactally where it is supposed to be, inline with the steering arm hole at full lock (or full ram ext), the steering radius is increased over a shorter arm.....If that makes any sense at all. The degree difference might be minimal, but there still is some. The closer to the center of rotation the ram is, the tighter the radius. The farther out the ram is placed, the smaller the turning radius....with the same stroke ram. You might not be able to get the full stroke out of the ram if mounted too close to the turning center, but if there was no limit, you'd be able to turn more.

I agree that you have more leverage with a longer arm, but if you use the same ram in both instances, the turning radius will be different between the two.

So do you want to have proper Ackerman steering, or are you going to butcher it like most people do?

Butcher it! Butcher it!

going with full hydro , have kin pin 60 , wondering what lenght of arms have you guys used for this application. I was told 7.5 " from the center of the kinpin to the center of the hole i got a set of arms but only measure out to be 6.5 would one inch make much diffrence? thks


It depends on how long your ram is. The ram throw has to match the knuckle movement. How tight you can make it turn also somewhat depends on what axles and joints you're using.

On my buggy, the arms are short, 6.5" with an 8" hydro assist ram. It turns pretty sharp, and I had to clearance the axle yokes some.



So do you want to have proper Ackerman steering, or are you going to butcher it like most people do?


Fun conversation, but how much do you think it really matters? By the time you get tires big enough to want to run full hydro, and how the rig is going to be used, does any one really care if the Ackerman is right or not? Most high steer arms go for tire clearance rather than good Ackerman........from what I've seen.

Fun conversation, but how much do you think it really matters? By the time you get tires big enough to want to run full hydro, and how the rig is going to be used, does any one really care if the Ackerman is right or not? Most high steer arms go for tire clearance rather than good Ackerman........from what I've seen.

Well, I'll say this...I've driven my buddy's rig with a similar wheelbase & track width to mine, and he's got his tie rod w/full hydro behind the axle, using flipped standard D60 hi-steer arms. This effectively gives him reverse Ackerman, and compared to mine with the same locker configuration (Detroits on both ends), mine turns much better, even in 4wd. His turning radius is dismal.

Of course, my tie rod is still in the factory spot, and though it's designed for a wheelbase of ~140" instead of 109", it's still on the "positive" side of the Ackerman scale. If I had the opportunity to design a steering system from scratch I would absolutely try and get the Ackerman pretty close. I figure there's no downside to having it unless your tire/wheel clearance doesn't allow it, and in that case I'd get it as close as possible.

But, isn't the main issue with Ackerman scrub, rather than how sharp it will turn? On your buddies rig, what are the length of his arms, etc? I would think real excessive scrub could effect turning radius, if one tire doesn't really turn very sharp, but with most off the shelf high steer arms the Ackerman is going to be reasonably close.

Hey, I'm all for considering Ackerman, I did on mine, and it's reasonably close. But, I wouldn't call having it a little off butchering it. :flipoff2:

But, isn't the main issue with Ackerman scrub, rather than how sharp it will turn? On your buddies rig, what are the length of his arms, etc? I would think real excessive scrub could effect turning radius, if one tire doesn't really turn very sharp, but with most off the shelf high steer arms the Ackerman is going to be reasonably close.

Hey, I'm all for considering Ackerman, I did on mine, and it's reasonably close. But, I wouldn't call having it a little off butchering it. :flipoff2:

Well, a lot of 'off the shelf' arms place the tie rod directly inline with the kingpin, giving you zero Ackerman. Regardless of the tire/wheel combination you can usually do better than this with a little thought into it.

The issue with my buddy's rig is that his outside tire turns more than the inside one. He'd always complained about his turning radius, and until I had mine next to his and we compared what was going on, he didn't realize what was causing it. Basically we determined that with similar tires, similar width, and similar wheelbase, my steering setup with decent Ackerman angles gave a noticeably better turning radius than his with reverse Ackerman.

He did his entirely for clearance and ram protection reasons.

http://wehrs.no-ip.com/projects_pages/2005.09.26_hydro2/DSCN3964.JPG

although with some custom arms, it'd be really easy for him to set up a true Ackerman arrangement, and would probably outsteer me by doing so. I think he's considering this for the next time he's got his steering apart.

It seems like the OP has a bit of flexibility in how he mounts his ram and what arms to use...and in that case, there's no reason why you shouldn't put a little more thought into it and get things close.

thks for the info , but i still rather confused , am i going to buther my steering setup? maybe but i hope not. but i have a 2.5 bore 8 inch double ended ram that will mounted out front with hi steer arms. I never gave any consideration to ackerman , as i dont really know fuck all about it. I just figured with a shorter arm i would have to mount my ram closer to the axle to get it lined up properly. Problem is i was told i needed a longer arm , i ordered a longer arm but got shorter ones and since i am in canada it will be a pain in the ass to send back to the states and wait for the right ones to come. being xmas and all i bet be a month before i get the new set.

Just use what you've got, you'll be fine.

thks for the info , but i still rather confused , am i going to buther my steering setup? maybe but i hope not. but i have a 2.5 bore 8 inch double ended ram that will mounted out front with hi steer arms. I never gave any consideration to ackerman , as i dont really know fuck all about it. I just figured with a shorter arm i would have to mount my ram closer to the axle to get it lined up properly. Problem is i was told i needed a longer arm , i ordered a longer arm but got shorter ones and since i am in canada it will be a pain in the ass to send back to the states and wait for the right ones to come. being xmas and all i bet be a month before i get the new set.

The issue is matching the travel of the ram to the movement of the knuckle. If the arm is too short you'll hit the steering stops with too much travel left in the ram which will put pressure on the knuckles and ball joints (you haven't said what axle you're using), if the arms are too long you just won't turn as sharp. It's nice to have arms with no holes drilled in them, that way you can match the throw of the ram with the length of the arm to get as tight a turning radius as possible without binding the yokes of the axle shafts. The only way to do it right is to mock it up and measure. So, you have the turning angles to consider, as well as lining up the ram with the holes in the knuckles.

Ackerman angle has to do with the track that the inside and outside tire travel in when turning. The inside tire turns a tighter circle than the outside, and how much tighter changes with how sharp you're turning. Proper Ackerman angle is attained by running a line through the tie rod joint at the knuckle and the ball joint center out to the rear of the vehicle. If the two lines from each side intersect basically at the middle of the rear axle then you have good Ackerman angle. Many off the shelf high steer arms place the hole for the tie rod joint too far inside, to gain tire clearance, so a line through that hole and the ball joint crosses the rear axle too far outward so the intersection point of the two lines is way behind the rear axle. However, many of those companies claim good Ackerman with their arms. So, this is simply my understanding of the subject........