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getting classy chappy .... Class Act Fab Buggy *2

chaplinfj60 said:
not gonna cut and turn, trails only here. may add a bit more caster, but drive line angle will be number one.
i do like all the ideas for sure. keep them coming for sure.

thanks again
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Sorry for the bit of derail there.
 
gt1guy said:
I have to disagree on the caster. I don't understand why what was used from the factory could possibly have any relatable bearing on what we are building. Any of us. You guys are building tube chassis buggies that have absolutely zero in common with a bone stock factory truck..................which is where the factory caster #'s come from. Everything is different...................literally everything. WB, CG height, track width, F&R weight %, suspension geometry, tire size, full hyd steering, ect, ect.

I don't think there's a downside to running 10.....12....15 degrees of caster. But there are upsides.
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I 100% agree with you. Lots of caster is the way in a solid axle rig for both high speed AND crawling. More caster will keep your tires frome trying to roll under you wheels while turning and help the tires hook a lot harder as well as giving more return to center.

As mentioned, if you're not doing a cut and turn, pinion angle takes priority, so you will be limited on how much you can achieve. I would run as much caster as you can without binding your drive shaft.

Sean said:
You're not wrong....

The question then becomes, "What's the formula for determining the proper caster with all those variables?"....
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There is no "proper," it is a tuning parameter like everything else.
 
hmmmm with a high pinion i maybe able to get more over my low so there is that for sure thanks again for helping me understand the benefits.
 
gt1guy said:
I have to disagree on the caster. I don't understand why what was used from the factory could possibly have any relatable bearing on what we are building. Any of us. You guys are building tube chassis buggies that have absolutely zero in common with a bone stock factory truck..................which is where the factory caster #'s come from. Everything is different...................literally everything. WB, CG height, track width, F&R weight %, suspension geometry, tire size, full hyd steering, ect, ect.

I don't think there's a downside to running 10.....12....15 degrees of caster. But there are upsides.
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Agreed, when I changed my old rig from 2* to 7* it was a very notable change. My current buggy has the knuckles rotated 10*+ and handles excellent crawling and at higher speeds.
 
good news, chassis' (yes 2 of them) has shipped and will be delivered next week , wed is what it says. so after labor day we will start to build them out. the goal is get one to a roller, then build the next get it to a roller then take them to each of our houses to free up space. and work on them there.
as every one who has ever built anything knows some days you only get an hour to go out and work on it. if 25 minutes of that hour is travel one way it will take for ever to get done. anyway quite excited for sure.

and i also have decided to go down the rabbit hole of diy cnc plaz tables to help with all the little brackets and fun stuff that free handing sucks.
 
gt1guy said:
I have to disagree on the caster. I don't understand why what was used from the factory could possibly have any relatable bearing on what we are building. Any of us. You guys are building tube chassis buggies that have absolutely zero in common with a bone stock factory truck..................which is where the factory caster #'s come from. Everything is different...................literally everything. WB, CG height, track width, F&R weight %, suspension geometry, tire size, full hyd steering, ect, ect.

I don't think there's a downside to running 10.....12....15 degrees of caster. But there are upsides.
Click to expand...

When I had “load reactive” full hydro, it was good at about 8-9 degrees for “return to center”. Not sure what the up side would be for more. I would imagine more tire ware would be the downside, but I have no evidence of that.

Ghetto Fab. said:
Didn't guys used to run a lot of caster to help the full hydro systems return to center? With a non-load reactive orbital I'm not sure any amount of caster would matter as far as self centering goes.
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Geetto is correct here. When I switched to “non-load reactive” , there is no benefit to caster. (You can’t tell if anything for different caster angles) I suspect zero would be best for tire ware.

Unsolicited opinion,
I have run both on the same rig and I recommend non-reactive hydro. Return to center is highly over rated. And my rig is mostly on road. The only benefit I see to return to center is if you need to tow the truck/buggy without a driver.

I will qualify this recommendation to say if you are running close to stock steering ratio. If you are increasing your ratio dramatically, I suspect return to center might be a good thing.
 
pile of tubes arrived.... yay...


1724326876819.png
 
WaterH said:
Unsolicited opinion,
I have run both on the same rig and I recommend non-reactive hydro. Return to center is highly over rated. And my rig is mostly on road. The only benefit I see to return to center is if you need to tow the truck/buggy without a driver.
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So you're running full hydro on the street?
 
Since we're on a caster tangent. Anyone ever seen anyone run crazy caster on a crawler? Say 15*+?

There was a trend with rc comp crawlers where they would run like 30* or more of caster. It supposedly help the tires bite?
 
YotaAtieToo said:
Since we're on a caster tangent. Anyone ever seen anyone run crazy caster on a crawler? Say 15*+?

There was a trend with rc comp crawlers where they would run like 30* or more of caster. It supposedly help the tires bite?
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I'm curious about this too...if too much negative caster (top of knuckle is ahead of the bottom kingpin/bearing/balljoint when viewed from the side) causes the vehicle to chase cracks, then wouldn't too much positive cause the steering to be vague? (talking about on road at speed)
 
Sean said:
I'm curious about this too...if too much negative caster (top of knuckle is ahead of the bottom kingpin/bearing/balljoint when viewed from the side) causes the vehicle to chase cracks, then wouldn't too much positive cause the steering to be vague? (talking about on road at speed)
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I'd think so.

As far as crawling, I think it helps grab ledges, and possibly maneuvering when going down hill.

I've also heard lots of scrub can be beneficial for similar reasons. But there is obviously downsides to that.
 
Sean said:
I'm curious about this too...if too much negative caster (top of knuckle is ahead of the bottom kingpin/bearing/balljoint when viewed from the side) causes the vehicle to chase cracks, then wouldn't too much positive cause the steering to be vague? (talking about on road at speed)
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Dragsters and land speed cars use a fuck ton of caster. I can't speak to how they handle, but I'd think vague feeling steering isn't something they want. That said, they also don't have much of a turning radius either.
 
gt1guy said:
Dragsters and land speed cars use a fuck ton of caster. I can't speak to how they handle, but I'd think vague feeling steering isn't something they want. That said, they also don't have much of a turning radius either.
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They don't really want any steering at those speeds. :laughing:
 
gt1guy said:
Dragsters and land speed cars use a fuck ton of caster. I can't speak to how they handle, but I'd think vague feeling steering isn't something they want. That said, they also don't have much of a turning radius either.
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I wouldn't think vague would be desirable either.

What's their reasoning for running the caster they do?

And what are we talking....like 15º or ??? Just curious.
 
Sean said:
And what are we talking....like 15º or ??? Just curious.
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Tires flop over way more than they turn. My buddies familys fuel altereds and front engine dragsters are all like that but I don't have specific #'s.


Edit: Just sent him a text and I'll post up when he gets back to me.
 
I always feel dumb bringing up rc in these threads, but it is a great way to test crazy concepts easily.

These guys were running probably 40*+, like very aggressive. I haven't seen it in a while, but I don't follow it as much anymore and I think the portal craze made crazy caster much more difficult.
 
gt1guy said:
Screen grabbed this off a video. No way to measure, but it's a crazy amount. From where the spindles attach, that looks like 20*+


Capture.JPG
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What's their reasoning though?
 
Sean said:
What's their reasoning though?
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The more caster the more return to center it naturally has, the straighter it goes without wandering. You also dont want much steering angle in something going 300mph where a twitch of the wrist would put you through the wall. Want to really be mind blown... Most drag cars that don't use stock style suspension have 1 front wheel up to 5" further back than the other to have maximum rollout in the staging beams. Rear end is square with the chassis but the WB on one side is 5" shorter.
 
Sean said:
What's their reasoning though?
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The reason can really only be straight line stability..............at 300mph. I mean, that's all they do. I'm sure land speed cars are in the same boat. Knowing that more caster results in more return to center "force", it would also be true that more caster results in more force needed to steer the wheels. I'm sure "feel" has everything to do with it. Maybe safety plays a part too.
 
YotaAtieToo said:
I always feel dumb bringing up rc in these threads, but it is a great way to test crazy concepts easily.

These guys were running probably 40*+, like very aggressive. I haven't seen it in a while, but I don't follow it as much anymore and I think the portal craze made crazy caster much more difficult.
Click to expand...
Next up: your analysis of link angles based on a LEGO kit you bought:flipoff2:
 
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