Front suspension redesign

[teckn9ne]

Hello, I am looking to redesign the front suspension on my minitruck (it is on air ride with huge wheels). Now with that being said I would like for the overall package to include, minimul bump steer throughout the travel, well enough mannered on the street to daily drive, keep camber gain to a minimum, and most important of all to ride comfortably with a heavy 24" wheel. What design parameters should be my priority? The whole reason why I need guidance is because most of the books I have found all pertain to racing applications, not so much daily driving. Any help is greatly appreciated. I know this seems vague and probably a bit farfetched but thats the whole point I suppose!

 

[BrianPetersen]

Solid axle, or IRS? If IRS, is it upper and lower A-arm, or MacPherson? If it is solid axle, is it leaf spring, or coils with a linkage?

 

[teckn9ne]

Upper and lower a-arm design! The rear is a solid axle setup that has already been taken care of with a simple wishbone four link design.

 

[GregLocock]

Kinematics don't affect the ride, much, except for anti dive. It is a very good idea to include some motion of the wheel centre backwards as the suspension moves into jounce. This usually reduces your castor a bit at the same time.

Other than that I think you are wise to aim at a very neutral suspension initially, tho I'd be putting in a bit of toe out in jounce, 1 deg/ft or thereabouts.Camber gain should be around 3-10 deg/ft. semitrack gain should be less than 1"/ft.







Cheers

Greg Locock


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[teckn9ne]

Thats odd I've always assumed that anti dive would ADD caster in compression! Of those suggestions camber gain is about the only thing easily achievable haha. Ive also always believed anti dive to cause the wheel to move backward in compression, therefore causing my wheel to go farther into my firewall, also how would the toe out in jounce affect driving or more importantly tire wear at around 1" off the ground? would the amount you suggested be so small that it wouldnt matter? thanks for the help!

 

[GregLocock]

Yep, I'm recommending you reduce antidive, or add pro dive if you prefer.

All of those amounts are very small, your basic plan should be to design a neutral suspsnion apart from the cmaber gain and then carefully adjust it to give a little toe out and wheel recession.

In particular the toe curve is very sensitive.

Cheers

Greg Locock


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[eqkimball]

I'm a few months late here, but I used to build minitrucks. I had a bagged '97 S-10 on 18's.
Are you still working on this?

 

[teckn9ne]

Yes I am, started drawing up the front suspension a while back, but im running low on money so no real physical parts yet, still deciding on my camber gain, and how I'm going to find or make a rack and pinion narrow enough to keep bump steer down

 

[GregLocock]

Use a center take off rack, popular on FWD Hondas and so on. Also popular in the aftrmarket for steering box to rack conversions.

Cheers

Greg Locock


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[patprimmer]

The GM J body, Holden Camira, Vauxhall Cavalier, Opel Ascona and I think the Chevy version is a Cavalier all had a centre take off rack.

http://en.wikipedia.org/wiki/GM_J_platform

Regards
Pat
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