Steering, Suspension, & Brakes

tips, technology, tools and techniques related to non-driveline mechanical components

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roverman
Art Gertz
Winchester, CA.
(2992 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Serrated/slotted steering arms ?
Posted by: roverman
Date: May 30, 2012 01:36PM

Anyone using these ? Some "Stock Cars" do. Quick and easy changing of Akerman. Onward, roverman.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Serrated/slotted steering arms ?
Posted by: Moderator
Date: May 30, 2012 04:12PM

Based on everything I've ever read, Ackermann matters a whole lot more when you're pushing cars around in the paddock than when you're actually on track. Tire selection, camber curves, roll center height, getting rid of bump steer and/or at least arranging the steering for slight roll-understeer (instead of roll-oversteer)... all are undoubtedly much more important. Kingpin inclination. Scrub radius. Roll stiffness. Spring rate and wheel rate. Shock valving. Static corner weights. After all that's figured out, come back and worry about Ackermann when you have tire temperature readings. In the meantime, Ackermann is just a distraction from the basics. Or at least that's what I've been told by people who should know.


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1083 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: Serrated/slotted steering arms ?
Posted by: ex-tyke
Date: May 31, 2012 09:18AM

Poor Ackerman geometry results in increased tire wear while cornering - I can see why the racers ignore it's contribution to tire scrub.


Bill Young
Bill Young
Kansas City, MO
(1337 posts)

Registered:
10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

authors avatar
Re: Serrated/slotted steering arms ?
Posted by: Bill Young
Date: May 31, 2012 12:42PM

Curtis, poor Ackerman isn't nearly as critical on a race car, but I can tell you from experience that it will wear tires in a real hurry on a street car and affect handling as well. If it's not too far out you may not notice it, but get it right and you will certainly feel the difference in cornering, especially on turn in where it can really affect understeer or oversteer. If your car's wheelbase is close to that of the original car that the suspension bits came off of then the Ackerman will probably be pretty close, but make the wheelbase shorter or longer and the Ackerman really changes quickly and should be corrected. This was most common on a lot of street rods where components from cars with 100+ inch wheel bases were used on T buckets and such with wheelbases in the 80 inch range.


Moderator
Curtis Jacobson
Portland Oregon
(4411 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Serrated/slotted steering arms ?
Posted by: Moderator
Date: May 31, 2012 02:09PM

I sometimes get confused with Art's posts... is he just thinking about hypotheticals (as I often do), or thinking about upgrades to his GT1 racecar, or thinking about building the ultimate Jensen Healey? Is that Jensen Healey really a street car, or is it going to end up more of a track day car? Racers do some counter-intuitive things. For example, quite a lot of them deliberately run static toe-out to improve turn-in. Some racers also deliberately run zero or even reverse Ackermann.


roverman
Art Gertz
Winchester, CA.
(2992 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Serrated/slotted steering arms ?
Posted by: roverman
Date: May 31, 2012 02:54PM

Curtis and clan, It's all real clear in my head, but just "maybe" I should preface with my project of the moment ? Not true to form, I'm ONLY concentrating on the GT-1 car, now. I'm on a mission to race something other than a wheelchair,(retirement home). GT-1 car appears to have stock/un-modified steering arms. Since I shan't go changing what Huffaker designed, too much, I thought the car "might" benefit from more Akerman,(turn-in). I have been reading Carrol Smiths," Enginneer To Win", so shoot me. Thanks for the help-all, roverman.


MGBV8
Carl Floyd
Kingsport, TN
(3761 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Serrated/slotted steering arms ?
Posted by: MGBV8
Date: June 02, 2012 09:52AM

Well, if it's Huffaker designed & built, rather than re-engineer the car, I would just strap in & drive! ;)



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