Caster and it's effects on steering?

[David Hodgkins]

http://thefactoryfiveforum.com/attachment.php?attachmentid=17548&d=1367956693

So I took the 66P51GT project mustang in for an alignment yesterday after putting in a new Borgeson power steering setup over the weekend. Borgeson recommends 3-4 degrees positive caster. The Mustang has 17" rims and we have already enlarged the front wheel wells but the alignment place says they can only get between 1/2-1 degree positive caster.

What effect will this have on steering? How will we feel the difference? Should I go through the time and additional expense to enlarge the wheel wells again or can we get by with what we have?

:)

[Martin]

http://www.nogripracing.com/forum/showthread.php?p=326209

Does that link help?

For some reason, I was thinking of the bikes in the movie Easy Rider. The bikes with the long sloped front forks have a cruiser feel to them. More stable, less twitchy. Sports bikes have less of a slope, have a tighter turning circle etc.

Martin

[conmech]

have you driven it for awhile to let the suspension settle? More info needed.

[Jeff Kleiner]

More positive caster will tend to help the car track straighter and add stability. It also increases steering effort and improves camber gain while cornering. 1/2-1 degree positive is very low. Ever get ahold of a shopping cart with a wonky, wobbly wheel? That's kinda' what insufficient caster does.

Jeff

[68GT500MAN]

David,
More caster (to a point) allows the steering to "self center" after a turn and will make the car feel more stable. Since this is a street car, both are a good thing. I would drive the car with the current settings and see how it feels, if you do not like it then proceed with the modifications to the wheel wells.
Doug

[CHOTIS BILL]

I don’t know the person that wrote the article on caster but it seems to me he went on and on and didn’t really explain what is going on with caster. I think most of what he said is rubbish at least for cars with decent suspension like ours. Such as changing the caster may require you to use stiffer springs or adding caster will cause you to spinout on slow corners. Two big changer that do occur from adding more caster is straight line stability and faster turn in and both come from the same cause. When you turn the front wheels the frame of the car is forced to move up slightly. Watch the front end of a dragster when the wheels are turned. The more the camber angle the more the frame has to move up and the more gravity tries to move it back down causing the steering wheel to return to the straight ahead position giving you straight line stability. When you turn weight is transferred to the outside wheels and the more caster angle you have the more weight is transferred to the outside front wheel giving you quicker turn in. Straight line stability and faster turn in are generally good thing but they come with the cost of harder steering. You have to raise the front of the car up more. To overcome that problem you can use power steering. But that comes with the cost of weight, more money, and complexity. Even though you only change the caster angle a few degrees it can make a big difference in how your car handles.

Bill Lomenick

[skullandbones]

Sounds like you were headed in the direction of the larger castor number with the addition of PS. You've added the complexity and spent the money so why not go all the way and get the benefit from the added castor. I would try a much profile tire in front before doing surgery on the wheel wells but since I don't know where you are having the issue with clearance that my not be an option. It can get pretty expensive to modernize the suspension for real nice track handling but when they do it on TV, somebody else is usually footing the bill (ha)! You have a nice project going though. Good luck. WEK.

[conmech]

I hope our "texting session" helped out. Let me know after the drive.

[David Hodgkins]

Good news, they were able to get 2.5 degrees by adjusting the UCA's.

I'll let you know how it drives this afternoon!

:)

[conmech]

Good news, they were able to get 2.5 degrees by adjusting the UCA's.

I'll let you know how it drives this afternoon!

:)

Ahh, a little bit of breathing room, lol. :cool: