Quoth - "Other than the truck rides pretty stiff, I am happy with it." There's your answer, with no suspension movement, there will be no toe problems. Seriously, that setup is poor engineering, and will lead to problems. I also do not necessarily agree with the idea that one needs to try something before stating that it is a bad idea/won't work. There are lots of ideas that are simply wrong from an engineering standpoint and do not, therefore, need be tried. Bumpsteer can easily be check before the car is driven, as can toe change. As far as a rack/straight axle front, I, personally think it is trying to engineer something into something else. As with most things automotive, if the OEM's have'nt done it, ever, it is likely not that good of an idea. If there are those out there that think that a rack and pinion steering is a relatively new idea, may I remind you that Citroën have been steered by a rack since 1938, but that they were four wheel independent suspensions at that point, too. But, hey!! It's your car, and your life, and this USA is, at this point, a free country, where you are allowed to flaunt your knowledge (or utter lack) of things automotive as you wish. Not every country allows such rolling examples of shadetree engineering to run free. Now don't attack me with the line "I've never had an accident with this"; because most accidents, up to the point of impact, can be prefaced thusly. Cosmo
This is something that I grappled with on my build and decided to go with a vega box and crossover steering....I did not know about the flaming river telescoping shaft though. The only way to achieve proper steering geometry is to mount the rack to the straight axle. In doing so, you must make up for the movement in the steering linkage....such as a telescoping shaft. Freightliner actually went to a rack and pinion setup on their Class 8 trucks last year. Their reasoning was fewer parts to wear out, weight savings, and better steering feel. See if this link to their website works: http://www.daimler-trucksnorthameri...s/images/11_06_steering/11_06_steering2_h.jpg http://www.freightlinertrucks.com/inside-freightliner/news/news-detail.aspx?id=605
This is going down the same path that had been beaten to death in the past. Some agree some don't leave it at that.
Anybody have a picture or info on what year and model to get this Mustang/Festiva slip joint thing. I really do not want to pay Flaming River $300.00 for their stuff. Thanks!
Pretty sure OEM's have done racks mounted to the firewall area on FWD cars, I seem to recall my mom having a Buick with a Quad4 in it, and the rack attached to the firewall..or maybe I just took too quick a look at it back in the day.
OEM's did indeed mount the rack to the firewall. But most (not all, most) front wheel drive are independent suspension, and those that aren't don't use racks. I'm gonna be looking for the rack on the Freightliners, Coke has new ones, and I'll see one tomorrow. Cosmo
Connect it, as if it was a Vega box, only to the right wheel. And then connect the right wheel to the left wheel. That must be the safest solution. Lars
My truck rides stiff because it has no weight and very stiff rear springs. When I say stiff,I say that because I am comparing it to my 06' Chevy that rides pretty damn smooth for a truck. Not stiff like jarring can't handle all the bumps and it is driving me nuts stiff. It rides like any other hot rod I have driven with old cross spring/leaf spring setup... So damn closed minded sometimes... ReallyI don't have the problems that people speak of, and all the people that I have ever spoken with don't eiether except a couple had really shotty workmanship.
Bringing this thread back to life to keep someone from becoming dead. I have been looking into doing this and have come across tons of recalls and a slurry of reliability issues. All of the rack and pinions on the class 8 05-2010 Freightliners were recalled due to the arm's fracturing and causing rollovers. The system is known to cause toe in and premature tire wear due to the arms which become loose within 180k. A cross over steering system is simply safer. If equipped with hydraulic assist ram will cause next to no bump steer, is easy to align, and will allow for a huge amount of travel. I have put over 250k on my current 2010 freightliner and over 500k on my previous 2006 freightliner with no steering issues to speak of. Both have cross over steering and have had weight of 12k on the axle at speeds at 70 mph hitting obstructions without fail. Cross over steering just works. Rack and pinion steering is made for light duty applications. It is a fact that if the rack holds true preventing bump steer and the tire hits a obstruction which pulls the large heavy duty wheel something has to give. That fuse is the arm, when that arm is bent or the threads are pulled from the housing the tire will be forced out or in unexpectedly pulling to one side. This can cause a roll, spin, violent pull, or worse. Light duty applications use rack and pinion because it is lighter and allows for more engine space. If you want to mount something to the axle mount a standard steering box to the axle then run a link to a one side and have the other side connected with a cross over. This allows for a ram to be used to assist. You can turn 40" tires with this system and it is proven. The steering box will blow the seals before the link arms break when proper heims are used. This will allow you to still have manual steering in the event of a seal rupture. Being under pressure the steering box can be mounted at any angle up to full vertical and use a slip shaft and cv joint at the steering box. This only makes sense on a application such as a cab over where the steering wheel is directly or closely over the axle. In any other application a frame mounted steering box and cross over steering system is superior to any form of rack and pinion.
I have found no steering column shaft components that are rated for the constant cycling of a suspension system. That takes properly lubricated, forged, hardened steel components, not mild or stainless steel components. Please commit suicide in a safer way.
These threads are interesting....here in british columbia canada, ANYTHING welded or made up in a non stock fashion in the steering gear won't pass a provincial inspection. A rack mounted to a solid axle with a slip joint is an automatic fail, thats the law. Not saying its right or wrong, but to title a car here it'll have to pass a provincial inspection, I'm sure thats gonna be the case elsewhere.
I too love these kinds of threads, I am sure all of us have been to shows and seen things and wondered how in the hell did it get there. If you talk to the driver he loves it and it stops, steers or handles great. It really depends on what the driver thinks is great. I have friends that say it handles great and when I drive it I'm scared to death. Some people don't know what bump steer is and think that the old car is supposed to do that. Open pipes, no scrub line, no shocks, no windshields, no front brakes and they love it. Different strokes as long as the parts don't fall off in front of me or get the law to start checking us all.
I am all for innovation. Taking something and making it better for your application is what makes this country great. I simply did not want people thinking that cause it works for the class 8 trucks it will surly work for there heavy duty 5ish ton truck. Like I stated they recalled tons of them due to the fact that the arms can and did fail. I am a huge fan of simplicity in a ride. Rack and pinion has it's place in the same manner as a light weight axle. If it works for the application great. But, improperly used things will break and in the case of rack and pinion seriously injury can be the aftermath. Breaks and steering are two things to overbuild on in my mind. If the engine, transmission, or axle goes at least I am confident I still have some control.
You can mount a r/p to the side of the frame and use it like a ordinary side stear and just use one side of the rack to mount the draglink if the body is chaneled over the fram you wont see the rack. just remember to have the joint from rack to draglink pivoting at same place as the wishbone/hairpin
Amen 26 roadster, I see a lot of questionable "stuff" that the owner is proud of, seems safety takes a back seat to what a good idea may or may not be. Having never driven something with a rack mounted to the axle, I'd like to sometime. Remember the early pinto cable flex joint steering hook up? The one that made a few months production? I've seen it used, although I'd think twice, it could be argued that it is a factory set up.
Certainly unlikely to get the thing (legally) on the road here in N.Z. nowadays with that engineering calamity...
Since this has come up again, I'll weigh in with the "don't do it" side... Having said that, I have been running an axle mounted rack on supermodified circle track cars for 15 years, and they ALL use them; have since the 80s. The trick is, the intermediate shaft from the column to the rack MUST match the arc of the suspension travel. With parallel leaf springs and rear shackles this is almost IMPOSSIBLE. With a 4 bar or front mounted leaf shackles, there is a definite attachment point at the frame on the steering shaft side of the suspension. If you can line a u-joint up near that point, and match the angle of the shaft to the angle of the bars (or leaf spring), you will have near zero "slip" as the suspension cycles. There are some very good, greaseable slip spline setups out there, some even have rubber dust boots on them. This is not a place for the old "2 pieces of square tubing" slip shaft garbage. Still not a good idea on the street...
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