Another bit of information not stated is that the steering arms can be longer to help them move outward toward the wheel on front steer. The arms front or rear steer can be lengthhend to help with positioning without affecting steering. The wheels don't know or care how long they are. On side/traditional steering shortening or lengthening the steering arm will greatly affect the steering ratio/force needed to steer. Shorter makes steering quicker and harder, lengthening slows it and steering is easier. The exacct opposite happens when dealing with the pitman arm. A shorter arm will steer easier and slower, and a longer arm will give faster steering and be harder to steer. I think most here will agree, open wheel rides look more cosmetic with the tie rod behind the axle. In all but the most extreme situations, with solid design and planing the tie rod can be setup behind the axle.
BAMABUCKET...I know that you didn't start this thread but it's interesting that you jumped in here. Most of this discussion has been based on questions YOU asked with regard to your particular car, and they've all been GOOD questions. I think it's "the guy" that DOES NOT ask or consider these types of questions that is liable to end-up with problems. Front end geometry is complicated stuff, and please believe me...I AIN'T NO EXPERT!!! It's been good exercise for ME to re-address some of this stuff. With regard to your particular experience in the trailer and the loose straps, me THINKS (what do I know) that it probably had nothing to do with your positive scrub. MY opinion of what happened, in your case, probably had more to do with the degree of POSITIVE CASTER (here we go again...MORE front end geometry terms) that's built into your front axle. In the case of a straight axle, POSITIVE CASTER is the tilting REARWARD of the TOP of the SAI, or the kingpin in YOUR case. POSITIVE caster is usually a desirable feature on vehicles that travel FORWARD (automobiles) at any real speed. CASTER even comes into play on your Kroger grocery cart. It is the setting that TENDS to help your steering return to "straight-ahead" after making a turn...good stuff. I also believe that ANY caster angle (POSITIVE or NEGATIVE), dictates that the front of the vehicle will LOWER as the steering is turned EITHER side of STRAIGHT-AHEAD. Gravity and bouncing-around in the trailer made it "find" the position in which you found it. I believe you found the proper solution to subsequent trips. Getting back to SCRUB...here's a little more food for thought. As was said earlier, you can change the scrub by moving the tires farther inboard OR outboard...BUT...you can ALSO change the scrub angle by INCREASING or DECREASING the outside diameter of the tire. How 'bout them apples? Front end geometry is complicated stuff...more goin' on here than meets the casual eye. MR. BAMABUCKET...Ain't NOTHIN' wrong with YOUR rig! NO NEED to change YOUR scrub. Your tires obviously haven't self-destructed or worn themselves out in spite of the "IMPROPER" scrub angle warning posted by someone above. If nothing else, this thread has opened some eyes regarding some of the physics of front end geometry that is involved when WE build or modify these old cars we play with. Physics IS physics...we CANNOT change physics. We can only try to understand them and work with solutions to overcome DETRIMENTAL geometry. AIN'T NOTHIN' I'd change on the front of your BUCKET...BAMA! I STILL like your car. DD
You'll find that most stock vehicles designed within thew last fifty years or so are set up with a small amount of positive scrub angle right off the factory floor, (usually within 1-2% of tread width). This contributes to a "positive road feel" as you drive your car. It adds to another physical property known as tire slip angle, but that's just going deeper and deeper into stuff we really don't need to delve into. Bamabucket, your front end setup looks good, I wouldn't change a thing. Allsteel36, I think your kinda missing the point of what the discussion is. Two right hand spindles would give an arm pointing forward and an arm pointing back. not what were looking for. At it's simplest, Ackerman can be described as drawing a center line from each kingpin to the center of the rear axle. Whether your steering arms are behind the axle or in front of the axle, the tie rod connections should fall within those lines. This will give the proper turning radius for both left and right front wheel. Pretty simple when it comes down to it.
Louver's, What I'm referring to is Right Hand Drive...where the crossarm and tie rod are on the drivers side (in the US on LHD cars), and single hole steering arm on the passenger side (again, looking at it as a US car) for the pitman arm. Just loking at them, if they were swapped side to side, both steering arms would be out front.
I understand what your asking. Interesting question, as it introduces some "new" parts into the possibilities for use. Won't fix the problem, though. Do the visual lines between TIE ROD pivot point, kingpin and center of rear end...doesn't compute. Remember, we're talking about TIE ROD pivot points...not the third hole where the steering INPUT comes from. DD
I posted in this thread just to give my opinion on front steer and have gained a wealth of information because of it. Thanks to you guys for sharing your tech knowledge. It looks like there are strong opinions about whether front or back is better and nothing is likely to change that, but can be no disagreement that proper geometry is absolutely necessary for a safe handling rod. I don't have anything to contribute, but will continue to follow the thread as long as it stays open in hopes of getting even more good info.
I haven't looked it over hard enough yet...it just came to my mind reading through this discussion...I'd assume Ackerman would be okay on a stock I-beam axle? So swapping sides should still keep the same relationship. I'm not trying to argue a point or anything, just wondering if what I have would work in the future as-is.? Thanks.
If you swap sides and put the tierod out front you have created the same reversed Ackerman effect that this post is hoping to correct. Re-read the post carefully and you should begin to see what the issue is. Your car being left or right steer originally has NOTHING to do with the Ackerman principle. Just as an example...If done correctly the inside tire will turn more at full lock, while if done incorrectly the OUTSIDE tire will turn more at full lock. The inside tire takes a shorter radius turn than the outside...therefore the inside tire needs to turn sharper.
Man, you've got a way with words, HACKERBILT. Well put, and I fully concurr with the way you make your point, for what that's worth. DD
Oky, NOW I see what you folks are speaking about....Hakerbilt. thanks for the simple expantion, DD...thnks for hanging with me!
This has been a great thread and I would like to thank EVERYONE for hangin' in there. What's important here is that everyone has been open-minded and willing to put the ol' thinking cap on. With regard to this front end geometry we've all been discussin' for the past two days, this is a very deep subject and we've only touched on the tip of the proverbial iceberg. There's so much more to this subject that I wish I fully understood. Hopefully we ALL, me included, learned something worthwhile from these pages. DD
My only problem with the HAMB, if every good thread was stuck as a "sticky", we'd have to get through 5 pages of "good stuff", to make a post! Viva La Hamb!
FWIW, and I beleive this is still on topic for this excellent thread, there is a new company operating out of the same building that Total Performance did (with common employees too) that is offering many of the parts that Total Performance made before they were sold to Speedway. (BTW, I was told that in the latest issue of Speedway's catalog there is no mention of TP any more. Although a search of their site did get some vague results, the steering section did not have the above mentioned steering arms. The new company is called Wintec Fabrications and they do have the T-bucket steering arms mentioned above. Here's the link: http://shop.wintecfabrication.com/product.sc?productId=17&categoryId=2 Now, back to the excellent discussion re. Mr. Ackerman........ Dennis
I saw this thread still in the churn and thought, WTF?! This must be the best thread yet on this topic. Nice work Gentlemen!
Wow, thank you sirs, very good thread. I have been schooled and for that I'm very grateful. Thanks, Jerry
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