Custom I-beam (2WD) design/fabrication???

atomicjoe23

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Hey can anyone point me in the right directin to learn more about designing/fabricating an I-beam 2WD suspension???

We just finished competing in a collegiate miniature 4 hr. endurance race and one of our shortcomings (our first year) was that our turning radius was too large. . .one of the reasons was because we didn't have enough weight on the front end to allow the tires to maintain good traction in tight turns. . .due to the rules of the event about the only way that I can get more weight on the front wheels without increasing overall weight is to put the driver farther forward. . .I don't want to increase our wheelbase either because it was perfect for the event. . .that leaves me two options compromise the geometry and travel of the front A-arms by mounting them outside of the driver compartment so the driver sits farther forward. . .not what I want to do because we had 7" more front travel than anyone else (that I saw or was made aware of) at the event and that was one of our major advantages or I can go with an I-eam set-up so that I can still maximize the front suspension members length/travel and still move the driver farther forward. . .putting more weight over the front wheels and increasing our ability to see what is going on with the front wheels. . .both of which would be welcome improvements.

If it helps anyone help me out here is what I'm shooting for and this is based on rules constraints. . .
1) max front trackwidth (outside of tires) of 64"
2) we want to keep our weight down to between 300-400 lbs. . .we were a little porky this year
3) wheelbase of ~76" (a little less is OK, but not longer. . .we want our turning radius to decrease not increase)
4) the front suspension as close to the corners of the buggy as possible
5) none of the suspension or steering components can intrude into the driver's compartment. . .

Thanks for the help!
 

Papá de Azúcar

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What is your UNSPRUNG WEIGHT? (tires, wheels, brakes, hubs, etc...)

What type of shock & springs did you run? Coilovers?
 

ErikShallbetter

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I don't want to post more because I don't want to give away any secrets until after all the comps are over but there are other ways around it.
 

atomicjoe23

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What is your UNSPRUNG WEIGHT? (tires, wheels, brakes, hubs, etc...)What type of shock & springs did you run? Coilovers?

Our unsprung weight shouldn't have been very much. . .we ran stock YFZ450 front knuckles, brakes, hubs and ITP wheels (10x8) with Kenda Klaw tires (22x7x10) and PEP triple rate coil springs from a DS650. . .

. . .in the rear we ran stock Polaris Outlaw 500 IRS hubs and ITP wheels (10x11) and Kenda Klaw tires (22x12x10). . .since it was IRS Polaris stuff the brake caliper and rotor was sprung weight. . .the rear shocks were single rate Fox Racing coilovers with Eibach racing springs. . .

I Beam is not the answer. Refine your front a arm design and keep progressing. Extreme camber and caster change will make a huge difference on the car.
We ran stock YFZ450 caster. . .our A-arms were fully adjustable for toe and camber so we can adjust that. . .speaking of adjusting stuff. . .we had ~0.75" bump steer in full compression but we had a LOT of bump steer in full droop. . .what can I do to reduce the bump steer??? Granted we had 17" of front travel on our buggy compared to an max of 12" on the other buggies at the event. . .

I don't want to post more because I don't want to give away any secrets until after all the comps are over but there are other ways around it.
We aren't competing in the Wisconsin event. . .if you wanna PM me and just throw some ideas back and forth I would really appreciate/enjoy it and I promise I won't give any of your secrets awaw. . .or you could even just email me at atomicjoe23@aol.com

We do definitely want to more evenly distribute our weight for next year and reduce our overall weight as well. . .which pretty much pushes us in the direction of moving the driver forward. . .I want to swap the position of the motor and transmission for next year as well which will lower our CG (wasn't an issue with our wide track width) as well as put the engine weight farther forward. . .
 

43mod

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is it a spool or differential? the poor boy fix might be turning brakes
 

1450-ranger

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Design and build your own suspension. Dont use off the shelf quad stuff. Pick up books and read.... Thats how you beat the competition. Books such as Engineer to Win, Tune to Win, Race Car Dynamics...

With an underpowered car, anything that slows you down is huge. Bumpsteer will slow you down and be ill handling from a driver perspective. Camber change will do the same.

Resourceful teams are who win in Baja. Less is more.
 

atomicjoe23

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We did build our own suspension. . .that's how we got 17" of front travel and 15.5" of rear travel while the rest of the competition only had 12" and 10" respectively. . .I'm big into building everything that we can ourselves. . .the only stock parts we used on the buggy were the front knuckles, the front/rear hubs, brake calipers and rotors, and the rearend. . .we will be building what we can to replace the stock parts that broke last year for next years race. . .
 

1450-ranger

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We did build our own suspension. . .that's how we got 17" of front travel and 15.5" of rear travel while the rest of the competition only had 12" and 10" respectively. . .I'm big into building everything that we can ourselves. . .the only stock parts we used on the buggy were the front knuckles, the front/rear hubs, brake calipers and rotors, and the rearend. . .we will be building what we can to replace the stock parts that broke last year for next years race. . .
Sounds like it needs some refinement. Good job for your first year, progression is key. Nothing happens over night.

Read up and good luck.
 

Zac Reish

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Does the amount of travel that you have in front impede on your turning radius? If so you shoud take out travel and find your sweet spot. 17" of travel is kind of over kill on a car that weighs 400 pounds. That would be like a trophy truck having 5 to 6 feet of travel. If it doesn't never mind.
 

atomicjoe23

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What impeded our turning radius was the lack of a rear differential and not enough weight over the front tires (it pushed on some of the tighter turns) more than anything else. . .really the only time we had any problems with the turning radius was when we were pushing it or when we were going really slow. . .
 

atomicjoe23

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OK. . .humor me on these two things. . .

. . .I'm not intimately familiar with the I-beam set-up, I have spent quite a bit of time looking at the TTB set-up though (I own a '79 F-150 4x4 that I've been thinking about converting from a straight axle to a TTB 4WD set-up for a while). . .and I realize that they're very similar, but I haven't ever really got to look at an I-beam in person. . .

. . .could you guys post some pic's of I-beam set-ups for me. . .and explain what goes into making a properly functioning I-beam set-up (let me at least know what I need to do if I do decide to go that direction. . .)

. . .make a suggestion for a 2WD front suspension set-up that will be LT and very functional for a vehicle that won't have a lot of free space to work with. . .the problem is gonna be that in order to shorten my WB some and to get better F/R weight distribuition I'm gonna need to move the driver's area forward (single seat buggy. . .think of a miniature KOTH's rig). . .a lot of the buggys use A-arms, but they aren't ideal set-ups because the A-arms aren't very long because they have to be mounted outboard of the cockpit. . .I will try and post some pics so you get a better idea of what I'm talking about. . .this is why I was thinking an I-beam set-up. . .by using an I-beam I could have a forward positioned driver area for better visibility (there is a rock crawl involved in this competition) and weight distribution but I could still have long suspension members in order to still have a long travel suspension. . .

. . .thanks!
 

atomicjoe23

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The problem is this. . .the series is restricted to one engine. . .and it can't be modified. . .so we all have the exact same HP, torque, and max. RPM settings. . .so power to weight becomes a HUGE issue. . .this series is all about chassis and suspension design not HP. . .

. . .we had a GREAT chassis design this year, but it was a little porky compared to the other rigs (it was our first year. . .and all we heard about was breakage, breakage, breakage. . .so we overbuilt). . .we have to cut the weight without driver down to about 350 lbs. to be competitive with the top teams. . .

. . .the rules are EXTREMELY restrictives. . .so you have to be EXTREMELY creative to have any sort of meaningful advantage. . .

. . .part of the rules being restrictive is our driver compartment. . .we will strive to make the foot/pedal compartment as small as possible but in order to have the best F/R weight distribution that we can we have to push the driver's compartment as far forward as we possibly can. . .which is good in that it will improve our field of view for the maneuvering event and rock crawl. . .and it won't hurt in the 4 hr. endurance race either. . .

. . .I basically want our wheel/tires to be at the 4 corners of the vehicle. . .I'm much less worried about being hit by other drivers after this past race than I initially was than I am about our approach/departure angles and our turning radius. . .

. . .so that's where I'm at. . .I don't think a J-arm is going to solve anything with respect to the length of the A-arms. . .

. . .I need to get creative in order to have a long travel suspension that will work with a competitive chassis. . .we had 17" of wheel travel in the front and 15.5" of wheel travel in the rear on this chassis compared to the 12"/10" travel of the other schools this past year and I would like to keep that edge but still make up on the lost ground we had in the turning radius. . .ultimately though, turning radius in this series is more important than travel. . .I just want to have my cake and eat it too!!!
 

atomicjoe23

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what parameters can be adjusted on an I-beam set-up???

I've spent the last hour looking at pictures of I-beam set-ups on the Blitzkrieg site and I got the basics down now, but it doesn't looki like you can tune much with an I-beam set-up. . .are caster and camber adjustable at all? I know I can adjust toe with the tie rods, but I'm not sure how you would adjust caster or camber with this type of suspension (if at all) which could be one of it's downfalls. . .

. . .are A-arms were completely adjustable for camber, caster, and toe this past year, but we really didn't have time to do much testing so we never adjusted them. . .so maybe for what we are doing and the speeds we are limited to being able to adjust caster and camber aren't such a big deal. . .I think that being able to have a long control arm on the type of chassis that I'm thinking of doing for next year is much more important to me than being able to adjust camber and caster. . .

Thanks for the help guys!
 

movindirt

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You adjust for camber/ caster @ the ball joints. The stock set-up uses eccentrics on the upper ball joint to allow for adjustments to align.

Some links: (disclaimer: I didn't fully read the threads that are link and therefore don't know how accurate the information is. Should give you some ideas no the less.)

http://www.therangerstation.com/forums/showthread.php?t=24

http://www.explorerforum.com/forums/showthread.php?t=60370


You should build in most of the camber caster that you want/need.. Camburg has used heims in place of ball joints to allow for camber adjustment. And I am sure if it was needed you could have different radius arms for different caster settings.
 

Triaged

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On the old Ford king pin stuff you just bent the beams to align them.
 
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