KOH discussion thread

Fabrik8 said:
I'm pretty skeptical of that design, just from looking at the one picture. It's a clever setup, but not without some compromises for everything but crawling.

It seems the only advantage would be to to limit the axle joint angles by spreading the angle over multiple joints, and maybe the secondary benefit of offsetting the driveshaft to the side of the chassis (if that's even an issue). Everything else is a detriment on that setup it would appear. The driveshaft location doesn't even matter that much, because you still have a stationary shaft with a fixed diff housing in an IRS setup.

You're adding a shitload of unsprung mass to the arm on that side only (from the housing, carrier, and some percentage of the driveshaft), so you've now got an asymmetric suspension setup, with different spring and damping requirements for the left and right, and inherently different response. That's mostly a problem at mid to high speeds, and not for crawling obviously.
I'm trying to wrap my head around what is happening with the torque reaction on the right side versus the left as well.

You're also trading center ground clearance for right side ground clearance. You've still got a housing that limits ground clearance, you've just moved where it is and changed where the clearance problem is during suspension travel. The housing is still going to be the lowest point between the wheels during many combinations of wheel travel.

I can't see what there is for trailing arms or whatever in side view, but hopefully there is something to adequately protect the driveshaft. Else it could be very, very exposed. It's almost always going to be higher than a solid axle setup at most points in the suspension travel, but it is very far to the right of the vehicle which means it needs protection from below and from the right side.

If the housing is centered like a standard IRS setup, you can move the arm pivots forward or back to clear the housing with no effects on geometry. Then the biggest problem is axle joint angles, which is a pretty big problem with that much travel.
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I'll address one....offset diff is much better than centered diff. The main reason i couldn't stand my front engine two seat car was the centered diff. An offset diff is much easier to get through the rocks because it moves with the tire. An added bonus with a solid front axle car with a front offset diff is that you can line up to obstacles knowing you have clearance on one side of the car front and rear vs clearance on one side in the front and a diff hanger in the middle in the rear.

Most might not think it's a big deal, but that's one of the top reasons I sold my two seat car (pictured earlier) and built another single seat mid-engine car.
 
Chris May's previous buggy, that was built as more of a technical crawler, had the diffs both offset to one side. It was also tiny and very good in tight stuff, but wasn't up to the desert racing.
 
Will Carter said:
I'll address one....offset diff is much better than centered diff. The main reason i couldn't stand my front engine two seat car was the centered diff. An offset diff is much easier to get through the rocks because it moves with the tire. An added bonus with a solid front axle car with a front offset diff is that you can line up to obstacles knowing you have clearance on one side of the car front and rear vs clearance on one side in the front and a diff hanger in the middle in the rear.

Most might not think it's a big deal, but that's one of the top reasons I sold my two seat car (pictured earlier) and built another single seat mid-engine car.
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I admire your commitment to improvement. :beer:
 
Getting longer a arms, without going stupid wide track width helps to get bigger travel #s

The main limit to ifs/IRS travel is arm length and cv angle.

As mentioned above, the ground clearance is far better with offset diff

The diff moves with axle, and is closer to the tire.

Think about it like break over angle, turned 90 degrees. You can get away with lower driveshafts with solid axles, yet need a higher skid when wheel base increases.

Yes torque reaction force only on one side,

But all of that can be adjusted through the control arm merge and control arm slope angles.

I think the change in unsprung mass is easy to deal with. A little more preload and some valve tuning and it's a non issue.

As far as arm lengths and locations vs a center diff, comes down to cv plunge.
 
Mac5005 said:
Getting longer a arms, without going stupid wide track width helps to get bigger travel #s

The main limit to ifs/IRS travel is arm length and cv angle.
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The diff housing isn't really a problem with arm length though. The pivots can be in front of and/or behind the housing, and the only thing in the way of having the arms practically intersecting in front of the housing may be the driveshaft (if the arm pivots are on the same vertical plane). Sure, you may need to move the inner pivots fore or aft along the same line of action about the pivot axis, but that doesn't change how the suspension works. Road race cars do that all the time.

You're still fucked by CV angle though, and there's no easy way to get around that.
 
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LBarr2002 said:
Chris May's previous buggy, that was built as more of a technical crawler, had the diffs both offset to one side. It was also tiny and very good in tight stuff, but wasn't up to the desert racing.
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Iirc Chris was all in with fj80 stuff. Offset different and offset case
 
Fabrik8 said:
The diff housing isn't really a problem with arm length though. The pivots can be in front of and/or behind the housing, and the only thing in the way of having the arms practically intersecting in front of the housing may be the driveshaft (if the arm pivots are on the same vertical plane). Sure, you may need to move the inner pivots fore or aft along the same line of action about the pivot axis, but that doesn't change how the suspension works. Road race cars do that all the time.

You're still fucked by CV angle though, and there's no easy way to get around that.
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Plunge, bro, plunge.
 
Fabrik8 said:
The diff housing isn't really a problem with arm length though. The pivots can be in front of and/or behind the housing, and the only thing in the way of having the arms practically intersecting in front of the housing may be the driveshaft (if the arm pivots are on the same vertical plane). Sure, you may need to move the inner pivots fore or aft along the same line of action about the pivot axis, but that doesn't change how the suspension works. Road race cars do that all the time.

You're still fucked by CV angle though, and there's no easy way to get around that.
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It comes down to the 9/10" center with carrier bearings and flanges being about 9" wide IIRC.

Then the flanges and cvs are farther outboard.

This is to get that less than that dimension, whatever it may be.

You get around the angle of the cv by widening the track width,

Accomplishes same goal as the proformance diff from AU but not 100k price tag for the diff.

Not sure what the price is for the Weismann stuff in the lasernut buggy.

Enough of that.

How awesome is it that Shannon is 3 time king and Waylon in 2nd with SC old buggy.

Also pretty amazing the number of ifs rigs that were in top 10.

And leadnav on an iPad for a navigation win.
 
You mean this Proformance diff? (Damn, won't let me link the pic I want)

It's so sexy though...

It does look like the Weismann is roughly the same concept as the Proformance. They're both really cool, I wasn't aware that they existed.

The Weismann appears to be a R&P carrier that drives a second carrier for the CVs? I like the simplicity and efficiency of the Proformance, but the Weismann looks like it could be mostly made from readily available gear components. I'm using my imagination and X-ray vision.
 
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This thread just grew wings and started flying right over my head:confused:
 
Mac5005 said:
How awesome is it that Shannon is 3 time king and Waylon in 2nd with SC old buggy.

Also pretty amazing the number of ifs rigs that were in top 10.

And leadnav on an iPad for a navigation win.
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Going to be interesting how things change next year w tireballs being outlawed. Clearly the Campbells can drive, but I suspect they are relying heavily on pushing those tires to (past) the max.
 
RatLabGuy said:
Going to be interesting how things change next year w tireballs being outlawed. Clearly the Campbells can drive, but I suspect they are relying heavily on pushing those tires to (past) the max.
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Id be interested to know how many of the top contenders were running tireballs?

I specifically recall Icenhour mention that he did not run them, but he didn't mention if he had any tire issues. He was 15th.


Combs raved about the KR3s not getting any flats, but Id bet she also had tire balls.
 
Will Carter said:
That's the reason I'm considering going back. Flat tires levels the playing field without spending as much money.
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What about the liners? Sounds like they aren't going to be outlawed.
 
rockcity said:
I'm glad it's over. I don't know how many more times I could stand to hear "powered by Optima Batteries..."
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I know. Vision X was the same during the shootout.

Funny how dark the track, obstacles, and hammertown got after the sun went down. Its like they rented a bunch of lights for monday at backdoor, but didn't keep them all week.
 
Will Carter said:
That's the reason I'm considering going back. Flat tires levels the playing field without spending as much money.
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Nevermind the speculation of cars in the $4-500k range nowadays. :)

Indy cars with bigger shocks and tires FTW!

I thought you were done with it entirely after selling your last car will. I'm pulling for ya from my ez boy recliner if you're back in!
 
paradisePWoffrd said:
Anyone hear where the CanAm finished on friday?
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Mike Bergman was the only one running one that I know of and he was a DNF.

On a high note Chris May was an official finisher. 48th place. Behind him as the last two official finishers...Derek West and Randy Slawson.


Will Carter said:
That's the reason I'm considering going back. Flat tires levels the playing field without spending as much money.
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I swung by the Campbell shop a few months ago on a work trip to Phoenix and Shannon was quick to express his feelings about the TireBalls rule coming out. It was along the lines of "you call it your unlimited class, so why the hell do you limit it".
 
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StretchASU said:
I swung by the Campbell shop a few months ago on a work trip to Phoenix and Shannon was quick to express his feelings about the TireBalls rule coming out. It was along the lines of "you call it your unlimited class, so why the hell do you limit it".
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Oh I don't disagree. But I can't play if tires are indestructable. Because then the more expensive stuff starts to break a lot and that's out of my budget. I told Dave back a year or so ago that I could come play again if tire balls went away.

Copied from my face space post back when the ball ban was announced:
"I'm all for the removal of tire balls.
And I'll come back to Ultra4 Racing sooner because of it. My last race was 2014 Superlift where I went from 40th starting (missed qualifying) to finishing 7th with no tire balls. I tip toed through that course and believe I was the only guy in top 10 that didn't have busted tires with tire balls hanging out the side. I realized that if I wanted to go faster I needed tire balls $$ so I could care less about the line and more about the throttle. But then I'd just bust more tires and wheels $$$ that are connected to a car I'd just wad up more $$$$ and... It was just the straw for my camel's back at that time. Busting tires keeps drivers in check, in turn keeping cars together for less money."

And I'm not just an inter web crybaby about how racing is expensive...I just stated the fact (to the man that runs the show) that if Ultra4 wants my money and show to come back then something was going to have to change. Otherwise I'd have to move on to other motorsports (although I haven't found one nearly as fun) that I could afford to play in. I don't think I'm the only one that felt this way...



paradisePWoffrd said:
What about the liners? Sounds like they aren't going to be outlawed.
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You know you're flat with a liner and performance is sacrificed immediately. I think the inner liners measure about 29" inflated. I don't know exactly, but how much could a thin bald 29" tire cost? I'd imagine a lot less than tire balls.


And I'll type it again: It's not the cost of the tire balls that are the issue, it's what the tireballs allow you to destroy over the course of a race because you don't have to give two shits about what you bash in to.
 
I'm not up on all the rules for a race. Is there a limit on how many tires you can use in a race. Yeah I get the fact a flat slows you down but if you got the money having 30 wheels and tires for KOH and change out tires after the rock sections even if they are still holding air just tot be safe seems like it could cost a whole lot more to be competitive if your competition could keep changing tires if you only had a half dozen

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