First Desert Mini Buggy Build

[elvergonmexicano]

Yeah, looking great...

and awesome welds!

[flyerrider]

Wow!!! *Top notch work. *I see you like incorporating as much plate work as you can. *I think high end plate work like yours is where you can really show off your craftmanship. *How are you planning to do the front bumper? *I'm guessing there will be a top rail similar to the Rorty cars. *Your exhaust looks amazing as well. *After just building my first set I can really appreciate how much time and effort goes into making it work well and look nice. *As far as the chassis being a little off, I wouldn't sweat it. *You'd be amazed at how much some of the high end race cars are off. *Last time I was at one of these shops I saw a guy with a 10K pound ratchet strap and a 4' lever pulling the chassis back into place. *It was still off by almost half an inch and it was "good enough"

[Damien]

Thanks, I'm not too worried about being a bit off either. *I don't know what I'm going to do about a bumper, I figure I'll wait untill the end when its rolling and I'm building the body to figure out what the bumper should be like. *It will definitely incoporate a curved aluminum skid plate though. *As far as the plate work goes, its kind of like fabricators chrome. *Its usually not the easiest method but it sure looks good when done right.

[K-fab]

Originally Posted by Damien\";p=\&quot

The rear suspension has about 30% anti squat with about 4in. of wheel recession.

Huh? *Can you explain this a bit more? *30% anti-squat?
4" of wheel recession?

Curiosity as to these terms has me.

The anti-squat has me....
I'm thinking the wheel recession is the offset of the rim?

I kept the plunge to less than .5 in. but I need about 40 degrees of cv articulation so I'm going to try non plunging cv's with 930 pattern and a regular coated splined slip joint. *I'm hoping since I have little plunge I wont need ball splines, but if stiction is governing the axial force then ?

If you only have .5" of plunge, I would think you could get away with not running the inner clip on one end (or both?) of the axle and using a regular straight axle like you would with a plunging CV.

A little axle slip in the CV probably won't hurt anything, as regular plunging CVs have a lot of axle movement, but I could be VERY wrong too...

The work looks excellent, by the way. *

[Rorty]

Hmm. I missed those remarks before (drawn straight to the pretty pictures), but they sound like the sort of phrases you hear university students rhyme off.

I understand anti-squat (though why you'd want it on an off-road car beats me), but I don't understand how you measure its percentage. What's 1% anti-squat? What's 100% anti-squat?

Recession sounds scarily similar to a term used in front suspension, but I assume it refers, in this case, to the amount the (trailing arm-mounted) wheel moves fore and aft as the arm pivots up and down. Am I close? *

[flyerrider]

How do you factor anti-squat in a-arms? *It is a rear A-arm car right? * Is it like reverse anti-dive (the front pivot on the upper arm would be lower I'm guessing)? *With 3 link or 4 link rear ends on trucks it is fairly straight forward (except for all of the different answers you will get from everyone as to what is acceptable) but I can't figure out the A-arms. *I can't see a front pivot on your rear bulkhead so are you implimenting rake in the rear end as well? *I've heard some negative things about that. *Not trying to take away from the build but you have some pretty experienced designers/builders a little confused here *. Can you please clarify.

[Rorty]

I've only ever incorporated anti-squat once or twice and those were road cars with double unequal length A-arms.

I just can't see how binding the suspension of an off-road buggy would be of any help on an already slippery surface. There are far more important areas to be chasing perfection than anti-squat.

I'm confused though, are we talking A-arm or trailing arm rear suspension here? The percentages Damien mentioned are probably in relation to the height the angle of A-arm pivots where they meet a vertical line through the COG, but for some reason I thought he was using trailing arms, but on reading back, I can't find any reference to them. Damien?

[plkracer]

All the anti-squat I've ever encountered is measured in degrees. 3 degrees means that the lower arm is tilted back 3 degrees. I raced r/c cars, and found it beneficial on the 2wd's for jumping, and steering under power, but the tires slipped more. It helped a lot on 4wd cars as it kept a lot of the weight forward, and allowed the tires to bite more without the rear end sagging and pulling the front off. If you want good steering under power with a little loss in acceleration, it may be beneficial. I guess it could be done with the trailing arms if you mess with the pivots and the wheel camber.

[plkracer]

I think it is an a arm car. The chassis is no wider than the rear plates. Looks like there are tabs too.

[Rorty]

Originally Posted by plkracer\";p=\&quot

All the anti-squat I've ever encountered is measured in degrees. 3 degrees means that the lower arm is tilted back 3 degrees.

I've heard that nomenclature too, but, and no offence, it's usually employed by people as a relative descriptive term or by those who don't know how anti-dive and anti-squat are calculated. Of course there's nothing wrong with experimenting and expressing the angle of the pivot axis in degrees.

The method of calculation does involve angles, but the results are expressed as a percentage of the distance between the COG and the ground. I'm happy to discuss it if anyone wants, but I don't feel it's appropriate for this forum. [ducks for cover] Someone will pop their head up and argue why they think anti-squat does have relevance in an off-road buggy.

Originally Posted by plkracer\";p=\&quot

I raced r/c cars, and found it beneficial on the 2wd's for jumping, and steering under power, but the tires slipped more. It helped a lot on 4wd cars as it kept a lot of the weight forward, and allowed the tires to bite more without the rear end sagging and pulling the front off. If you want good steering under power with a little loss in acceleration, it may be beneficial. I guess it could be done with the trailing arms if you mess with the pivots and the wheel camber.

Again, no offence, but the parallels between RC buggies and mini buggies would be limited; weight and the reaction of the dirt to that weight is probably the most obvious area they would differ in.

I see fundamental problems with anti-squat on the rear of a mini buggy; acceleration would be lost and the harder you mash the pedal, the worse it would get! The rear end would also be a lot more skittish in turns and the thing would be an evil beast at best. It would be a totally different subject if you were driving on bitumen where there's measurable amounts of grip.