The KRACKEN IFS/IRS buggy build

Lickliter21 · Dec 27, 2015

patooyee said:
Did I miss where you explained this more? I'm curious ...

I didn't go into it. I thought I had pics of the constant carnage but it appears i didn't take any or have deleted them if I did. Mainly the the Trailing arms/link suspension help slide over obstacles but with the rear A-Arms style i have it drops out and then more than half the tire has to make the climb. If that makes since.
The torque output has ripped/bent the round tube I've thrown at it. I'm really looking into the trailing arm independent rear. Just need to figure how to make it strong enough without huge amount of weight.

patooyee · Dec 27, 2015

Makes sense but why isn't that an issue in the front as well? Or can it not be addressed via geometry changes? What ratio is in the differentials? I understand that the portal hub provides 1.8:1 reduction but I assume you make up for that reduction / aren't insanely low with an uncharacteristically high ratio at the dif? That's probably why you went with the 9" dif in fact, being that 2.46 and 3.0 ratios are available. IE, the total reduction at the wheel isn't any more than a normal rig.

Sorry I'm asking so many questions. It's just so refreshing to see something relatively new in this world and when I do my curiosity just takes over.

Edit: It just dawned on me that you are suggesting literally using the trailing arm as a ramp to get to the tire in the rear which is why it isn't generally an issue in the front. (Unless backing up I guess.)

iron lotus · Dec 27, 2015

This build if freaking awesome.. way to go out of the box!

patooyee · Dec 27, 2015

OK, so now that I understand what you are saying, you do realize its not the torque multiplication that is killing it, right? Once you start trying to climb with the contact patch of the tire above the tire centerline you are no longer climbing, you're driving in reverse. Like when monster trucks and some guys flip over and the top of their tire touches the ground and reverses their direction of momentum, that is what you are doing in the rear. Basically your front end is up the hill driving forward and the rear is under a ledge in reverse along with the weight of the rig on it. So the rear will always win that fight for traction but your front end along with momentum is still pulling you forward. So you're going from like 90mph forward to instantly 90mph backward in the rear. I don't know many suspensions at all that could handle that. So yeah, maybe the trailing arm is a good idea.

Still the baddest rig I've seen in the past couple years. The ride quality looks amazing.

CHASMAN9 · Dec 27, 2015

Such a great out of the box build. This thing is going to be a force to be reckoned with with you behind the wheel Dean. Glad to see pictures of Richie where he's not on the crapper. Lol. See ya soon buddy. :dblthumb:

Lickliter21 · Dec 27, 2015

patooyee said:
OK, so now that I understand what you are saying, you do realize its not the torque multiplication that is killing it, right? Once you start trying to climb with the contact patch of the tire above the tire centerline you are no longer climbing, you're driving in reverse. Like when monster trucks and some guys flip over and the top of their tire touches the ground and reverses their direction of momentum, that is what you are doing in the rear. Basically your front end is up the hill driving forward and the rear is under a ledge in reverse along with the weight of the rig on it. So the rear will always win that fight for traction but your front end along with momentum is still pulling you forward. So you're going from like 90mph forward to instantly 90mph backward in the rear. I don't know many suspensions at all that could handle that. So yeah, maybe the trailing arm is a good idea.

Still the baddest rig I've seen in the past couple years. The ride quality looks amazing.

The transfer case is a 1.96:1 and the diff gears 2.91s. I get what your saying about the tires and centerline. But only really had that trouble at DTOR. I think it's the weight on the rear causing the biggest problems. The fronts really light and just floats over the ground most the time. Rears taking the brunt of everything. I don't have a die for 2" tubing so I sleeved 1.75x.120 with 1.5x.120. They bent. So I added a huge gusset over the whole area. It then snapped the tubes instead of being them. It always goes to the rear when it gets bent or broken. I don't know any other reason it would bend/break the uppers the way it has been. The lowers have not been a problem.

CHASMAN9 said:
Such a great out of the box build. This thing is going to be a force to be reckoned with with you behind the wheel Dean. Glad to see pictures of Richie where he's not on the crapper. Lol. See ya soon buddy.

Thanks Gregg can't wait to get out and ride/race with everyone!!

patooyee · Dec 27, 2015

Lickliter21 said:
The transfer case is a 1.96:1 and the diff gears 2.91s. I get what your saying about the tires and centerline. But only really had that trouble at DTOR. I think it's the weight on the rear causing the biggest problems. The fronts really light and just floats over the ground most the time. Rears taking the brunt of everything. I don't have a die for 2" tubing so I sleeved 1.75x.120 with 1.5x.120. They bent. So I added a huge gusset over the whole area. It then snapped the tubes instead of being them. It always goes to the rear when it gets bent or broken. I don't know any other reason it would bend/break the uppers the way it has been. The lowers have not been a problem.

Well I look forward to seeing how you get it figured out.

poolman · Dec 27, 2015

Very cool build! I'm originally from Lawrenceburg, next time I'm coming through I'll stop by. Congrats on building the first bouncer like this!

paradisepwoffrd · Dec 27, 2015

Re:

Guessing you don't have any videos of when its broke?

Might could keep the soft springs/shocks in the rear and change the anti-squat. Looks like the control arm mounts are parallel which won't likely have enough anti-squat

Sent from my SM-N920V using Tapatalk

Beerj · Dec 27, 2015

I've heard of guys running 1.5" 7075 sleeved with .120 1.75" DOM. Not sure if that would help much other than still being able to weld to the arms.

SRRS · Dec 27, 2015

It's really awesome seeing things built outside the box. The trailing arm acting as a skid is very true. The RZR's have shown this. It takes a little more momentum but the rear tire doesn't go below the ledge and try to pull under.

We tried to get the Proformance D80's last year for a IFS/IRS but they weren't available so we stuck with traditional setup. I think we'll see more IFS and possibly planetary setups to start bringing drive shaft and axle shaft sizes back down to loose some weight. Right now cost is very expensive on these but they're showing up in trophy trucks with big HP.

ButterfaceBikeShop · Dec 27, 2015

Gotta say this build was/is and has been a blast. Don't get me wrong its been a total pain in the ass at times. Its been awesome building this with my good buddy and Im/ we're crazy proud of it. I call Dean "Rainman". Dudes crazy pretty incredible and never ceases to amaze me. Pretty sure this buggy and build has gotten a ton of wheels turning in people heads. When Dean told me what he wanted and was thinking about building all I could say was HELL YEAH LETS DO IT! Ive got tons of pictures as well and will post them up on here when I get the chance.

ToyotaTom · Dec 27, 2015

Nice! I always wondered if there was a build thread for this thing. I was watching Penhall Fab build Ben Napier's car, cool to see the rock bouncer version of IFS.

xjpaddler · Dec 27, 2015

Trailinng arm IRS for the win!!!!????????

Dean you already know im a huge fan and am slowly collecting parts for something very simular. I can not wait to see it as more of the issues get worked out. And im sure i will be picking your brain more in the future.

One thing i have noticed with A arm style IRS is that no matter what the rig is, it always wants to rotate the car/rig around the rear axle, ( lift the front ) with a trailing arm IRS you can force that torque further forward in the chassis! This will help keep the front on the ground. And spread the load of the rear axle torque.

Love the idea of the portal, because they take so much stress of the drivtrain. Also allows for better cv angles.

Lickliter21 · Dec 28, 2015

SilverStarCustoms said:
It's really awesome seeing things built outside the box. The trailing arm acting as a skid is very true. The RZR's have shown this. It takes a little more momentum but the rear tire doesn't go below the ledge and try to pull under.

We tried to get the Proformance D80's last year for a IFS/IRS but they weren't available so we stuck with traditional setup. I think we'll see more IFS and possibly planetary setups to start bringing drive shaft and axle shaft sizes back down to loose some weight. Right now cost is very expensive on these but they're showing up in trophy trucks with big HP.

This things on a tiny 1.125 axle shaft. When they came in I was pretty skeptical. It's taken several full throttle landings and held up awesome. RCVs for the win!!!!
Cant wait to see what others bring to the table. That's what makes this sport great!

paradisepwoffrd said:
Guessing you don't have any videos of when its broke?

Might could keep the soft springs/shocks in the rear and change the anti-squat. Looks like the control arm mounts are parallel which won't likely have enough anti-squat

Sent from my SM-N920V using Tapatalk

Just about any vid of it on YouTube something has happened to the rear arms. Except when they broke completely. You can't see it in the vids. It looks like everything is still fine other than maybe the tie rod is at a funny angle.
There's a little anti squat but not much. I wasn't sure how much to put into it and kinda wanted it more neutral.

xjpaddler said:
Trailinng arm IRS for the win!!!!????????

Dean you already know im a huge fan and am slowly collecting parts for something very simular. I can not wait to see it as more of the issues get worked out. And im sure i will be picking your brain more in the future.

One thing i have noticed with A arm style IRS is that no matter what the rig is, it always wants to rotate the car/rig around the rear axle, ( lift the front ) with a trailing arm IRS you can force that torque further forward in the chassis! This will help keep the front on the ground. And spread the load of the rear axle torque.

Love the idea of the portal, because they take so much stress of the drivtrain. Also allows for better cv angles.

Portals are awesome. Just need the Proformance to make it easier to mount them lol.

Scott F. · Dec 28, 2015

Very cool build. I like the styling and the different build approach. I see you already answered one of the questions I had regarding where you sourced the half shafts from. Seems like if any could make ones that would last it would be RCV.

How are the portal boxes holding up to the 43s? Are they the 10k or 12k ones? Straight or helical gears?

TRD · Dec 28, 2015

Such an awesome build! Thanks for sharing!

I'd love to see what it can do with IRS that can hold up to the abuse. Don't give up too early, I think you've built something really cool!

For rockbouncing I think you have the right approach with soft valving, you want to absorb the bumps, not get on top of them.

paradisepwoffrd · Dec 28, 2015

Re: Re: The KRACKEN IFS/IRS buggy build

Lickliter21 said:
This things on a tiny 1.125 axle shaft. When they came in I was pretty skeptical. It's taken several full throttle landings and held up awesome. RCVs for the win!!!!
Cant wait to see what others bring to the table. That's what makes this sport great!

Just about any vid of it on YouTube something has happened to the rear arms. Except when they broke completely. You can't see it in the vids. It looks like everything is still fine other than maybe the tie rod is at a funny angle.
There's a little anti squat but not much. I wasn't sure how much to put into it and kinda wanted it more neutral.
Portals are awesome. Just need the Proformance to make it easier to mount them lol.

Only videos I've seen are from DTOR. I know you've done some tuning since, and might have helped alot. Looked like the anti-dive/squat on both ends were pretty low. That's why the front dives when you tap the brakes and you almost went over backwards when stabbing the brakes in the wheelstand.

You definitely want to keep it under 100% or the issue with tire undercutting will get worse. A trailing/L-shaped arm might help with both issues.

If you didn't want to redesign your susp, you could simply add a "telescoping slider" from the belly to lower arm. Since it would telescope, it wouldn't affect geometry.

TBItoy · Dec 28, 2015

Re: Re: The KRACKEN IFS/IRS buggy build

paradisepwoffrd said:
Only videos I've seen are from DTOR. I know you've done some tuning since, and might have helped alot. Looked like the anti-dive/squat on both ends were pretty low. That's why the front dives when you tap the brakes and you almost went over backwards when stabbing the brakes in the wheelstand.

You definitely want to keep it under 100% or the issue with tire undercutting will get worse. A trailing/L-shaped arm might help with both issues.

If you didn't want to redesign your susp, you could simply add a "telescoping slider" from the belly to lower arm. Since it would telescope, it wouldn't affect geometry.

How would a extra telescoping arm do anything on a A arm?