shafties....More GC in front or rear?

[solomon7]

Just wondering what's working for most.
For breakovers especially where do I want my highest point of clearance front of rig, skid/center or rear.
thinking of adding more droop in back but don't wnat to unbalance things too much.
Your input is appreciated!

I don't mean literally droop but more the max clearance of the rig at front middle or rear.
I see a lot of rigs designed woth more link clearance and higher GC righ in front of their rear tires.
Designs like BWD's Mantis MOA chassis or some of the sport builds in the AX10 sections.

[2500hdon37s]

honestly I dont like to run droop, but if i were to run some itd be some on the front shocks.

[Charlie-III]

Most comp rigs have the CG (balance point) towards the front (heavy front) but extra clearance towards the rear.
Front/rear weight bias of 60/40 to 70/30 is typical. You can check by weighing each axle (everything loaded, ready to run including battery) and then figuring out the weight bias.

Once the front axle clears an obstacle, the front weight helps tip the rig over it.

[opek]

I think people are misreading the poll. I'm 99% sure that by more droop in rear he's talking about more suspension extension ie more ground clearance.

[ghtpdm5]

clearance on a shafty is possible, you have to really watch your chassis weight and weight placement in general. also keep in mind that most shaft driven axles are not designed with clearance in mind, you're going to have to buy or make a new higher 4 link mount to make things work out. the losi axle for instance has very little link separation, you're chasing a dream getting a lot of clearance out of them. i finally got sick of it and built my own chassis and 4 link mount to get the angles correct so its not running squat suspension. this allowed me to push the full drop out clearance to 4.5 or so inches. don't overthink this stuff, its not rocket science to build a working crawler, study those trucks that you like and work from there. teams like t1e, y-town, cdw all make great chassis platforms and if you study them a bit, watch videos or see them in action, you can learn a lot



my losi in current setup. while i'm still working on the front suspension, the rear is dialed. as you can see, i stripped the chassis every component i could. all of that is on the front axle, 66% forward weight bias.

[solomon7]

May not be rocket science but there is geometry involved, and trig too.

Yes as opek stated above I'm speaking of final clearance.
My rig's geometry is pretty good I think.

105% AS Rear, neutral front, upper Instant Centers past the rig, high Roll Center with a R to F downward slope to the roll axis, low CG and 43* flex at 50/50 travel with 3.6" max GC, 2.85" ride height.

I just want to be able to at least come close to clearing some of the ledges the MOAs do but with a somewhat realistic rig instead of the Clod version 5.6s out there lol.

[ghtpdm5]

well, ledge clearing is what i chased down with that chassis and 4 link design. you are correct about geometry, a bit gifted in it, can just see what's going on and know what the truck will perform like for the most part. break over clearance is a hard one to get truly down. once you start chasing higher marks, you can't stop (at least for me). my rock pile has large breakovers and that belly dragging losi just couldn't do it, so i chased the exact same you're asking really, that's the final prototype before the production model. for me, the rear link and middle clearance has helped the most, really allows the rear tires to get some traction and make it happen. front clearance bending hasn't worked the best, tried it for about 5 hours of testing on my home course, wasn't beneficial enough to keep, ran into the drive shaft too hard.


so as to the question, i had to spend 6 months developing a chassis purpose built to be able to do break overs while still having good sidehill and climb performance. and once its released i'll get all the hard math up for detailed specs.

*do not contact me about this chassis, i just draw and sit with a calculator, i do not sell them*