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View Full Version : Front Steer vs. Rear Steer: Just Packaging?


Gyro
10-13-2011, 12:07 AM
Hey all,

My current steering design is a rear-steer Ackermann-type geometry, but it seems to me from my research that front-steer is more typical. Am I missing something out of simple ignorance, or is front- vs. rear-steer largely a matter of packaging considerations within your frame & wheels?

As always, comments pointing out my utter foolishness are welcome. Thanks!
Gyro
10-13-2011, 12:07 AM
Hey all,

My current steering design is a rear-steer Ackermann-type geometry, but it seems to me from my research that front-steer is more typical. Am I missing something out of simple ignorance, or is front- vs. rear-steer largely a matter of packaging considerations within your frame & wheels?

As always, comments pointing out my utter foolishness are welcome. Thanks!
JDS
10-13-2011, 06:56 AM
Front vs. Rear steer will significantly effect the direction of forces going through your tie/steer rods. Due to compliance's this can also effect the your toe under braking/accelerating, etc... Front steer is definitely more common, but that doesn't mean you can't make a rear steer system work well. But generally it is done because packaging requires it, not because it is desirable.
Gyro
10-13-2011, 09:48 AM
JDS: When you say the forces in the tie rods will be affected, do you mean that the tie rods will be in compression instead of tension when braking? If so, I can see why front-steer linkages might be preferable.

Thanks for your response!
BillCobb
10-13-2011, 01:18 PM
Front steer gives more favorable steering shaft geometry (straightline) and a likely stronger gear attachment support structure. But only if a transmission is not in the way.

Plus, when fighting a snake, it's better to pull on a snake than push on one, especially when the rack and the snake are coaxial.
Gyro
10-13-2011, 10:25 PM
Bill: That pretty much matches my intuition on the subject. Except for the snake part. Thanks for the input.
Tim.Wright
10-14-2011, 02:46 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Plus, when fighting a snake, it's better to pull on a snake than push on one, especially when the rack and the snake are coaxial. </div></BLOCKQUOTE>

Thats just what people who have a floppy snake say http://fsae.com/groupee_common/emoticons/icon_wink.gif
The_Man
10-17-2011, 05:00 AM
Big Bird post had helped me make the decision a few years ago.

http://fsae.com/eve/forums/a/t...607348/m/21210681341 (http://fsae.com/eve/forums/a/tpc/f/125607348/m/21210681341)

Having said that packaging was still the most important factor for me, as it was the first year with the template rules.
The_Man
10-17-2011, 05:02 AM
Tangent:

Wow! that link went through without moderation. Since when did things change round here?