Speed UTV

[HEADINJURY]

I believe when Recreational driver rolls their sand vehicle in the desert it's one of two reason's why...

1.) Ran out of talent. 

2.) Was hit by another person who has no talent.

Plain and simple, if you roll your car in the desert, you ran out of talent and you were driving above your ability. 

 

[HEADINJURY]

I hear you.  Like all things, it depends though. :biggrin:

Trailing arm is going to be harder on CVs.  Just ask any buggy guy.  You don't hear about SxS guys arguing about what grease to use, complaining about pitting stars, etc.  Part of it's the power, but another part is plunging CVs pump grease and need more maintenance.  You also can't really dial any anti-squat in, so you're at the mercy of the spring rate to dial that out.

Yeah, the track width change is sub-optimal, but I don't think it's make or break.  I go from a trailing arm buggy to a Can Am all the time, what I notice is the lack of turn in and "pointy front end" more than the rear suspension tracking funny.  Lack of turn in is because it's tuned "safe" geometry and spring rate wise.  It's fine, and I can get it to hustle quickly enough, it just requires driving style adjustments that are less fun.  Compared to most buggies, the stock Can Am soaks up bumps way better.

Parts break.  Trailing arms will have more stress on the two pivots since they see more leverage, forcing you to run much heavier components, and if something breaks it's usually terminal. Definitely an easier design to make beefy though.

Trophy trucks don't have trailing arms (they're technically trailing links) either. :biggrin:

Either way, Robby pointing at one geometric aspect of a vehicle and saying "mine's bigger" is misleading.  Look at the whole system, make your judgement. I think conversations like this are educational and fun, no hard feelings here. :biggrin:

Rockwood, I don't know if we've ever met, but I have to say you're either the smartest dude here ever on glamisdunes,com or one hell of an actor! j/k about the acting part. Props to you! 

Everyone else i.e Bench Racers and wanna be race car drivers stand down when Rockwood is in town. You'll probably say something may later regret. 

Again huge props to Rockwood! 

BTW are you retired? Or available for some consulting?

 

[Rockwood]

Also, since this is a semi-trailing arm designed with a low roll center and camber gain (which probably goes positive under droop), curious how they addressed the resulting lift-off oversteer.  

Rockwood, I don't know if we've ever met, but I have to say you're either the smartest dude here ever on glamisdunes,com or one hell of an actor! j/k about the acting part. Props to you! 

Everyone else i.e Bench Racers and wanna be race car drivers stand down when Rockwood is in town. You'll probably say something may later regret. 

Again huge props to Rockwood! 

BTW are you retired? Or available for some consulting?

Me? I'm just someone who's learned from Nissan, TRD track support engineers and Mazda chassis engineers way smarter than me. My automotive days are looong gone.  

If you've met me, you certainly wouldn't call me the smartest dude, LOL. :biggrin:

 

[michael.gonzalez]

Yep.  But for the phenomenon of jacking, it's the same physics whether it's the front of the car or the rear since we're talking about body roll.

View attachment 41033

Roll centers will be "all over the place" here as well.  Just because it's on the front, doesn't mean the "problem" goes away.

But yes, vehicle dynamics is a consideration on every vehicle, which is why I don't like Robby's team pointing at one minor problem (in the grand scheme of suspension design) and saying "their cars suck, mine rules".  You're making my point: there's a lot of design characteristics to consider and there isn't a "correct" suspension design as the goals can vary wildly.

For example, if handling balance for the everyday Joe is a consideration, causing dynamic changes in the elevations of the front and rear roll centers (roll axis) will cause a vehicle to be a bit rear balanced and can cause problems.  Trailing arm rear/parallel link front arms will make it handle more like a "buggy" since trailing arms don't have great A/S and the front geometry's "all over the place" roll center will make the downward sloping (trends towards oversteer, all else equal) roll axis increase at a non-linear rate.  There's a gazillion other things the chassis engineers can do to combat this, but in the end, that's the geometric balance, so anything you do will have some other knock-on effect elsewhere. 

For guys like me, this oversteer bias is good.  For idiot Joe Schmoe Arrive and Drive, this may result in a trip to Brawley.  All in what you want. :biggrin:

Damn, they should hire you! You know everything. How many suspensions have you designed?!

Have fun with your front trailing arms!!

 

[Sand Shark]

Damn, they should hire you! You know everything. How many suspensions have you designed?!

I think he told us about is automotive background. 

Here I thought setting up my kid's r/c buggy for racing was a mind "F", you guys are doing it with SXSs.  LOL!

P.S. - Where is @Lord of the Dunes when all this technical talk is going on?  He likes to talk shop.

 

[jginsandiego]

Anyone get their call saw this today.

 

[CampfiresNbrews]

Rockwood, I don't know if we've ever met, but I have to say you're either the smartest dude here ever on glamisdunes,com or one hell of an actor! j/k about the acting part. Props to you! 

Everyone else i.e Bench Racers and wanna be race car drivers stand down when Rockwood is in town. You'll probably say something may later regret. 

Again huge props to Rockwood! 

BTW are you retired? Or available for some consulting?

Definitely one of the smarter dudes here. But if I have to choose who’s going to design my “Off-road” vehicle, well that vote goes to RG and his pedigree of how a proper off-road vehicle should  be set up. Like the video I posted earlier, you have book smart geometry (Rockwood)and then there’s off road geometry. (RG) Both are good but each have their place. 

 

[Kat-A-Tonic]

It sounds like drivers of other SXSs have no prayer of keeping them on 4 wheels.  So if a Speed UTV ends up flipping was it merely because the driver messed up? 

You and Rockwood lost me with all the lines and technical talk.  I am going to stay at a Holiday Express tonight and learn engineering.  LOL!!!

We might have to have Jason drive one to really find out, LOL.

 

[Vikter]

Do any of you SXS guys have insurance coverage in AZ for street/liability use and damage. I have never had a sxs only several street legal 4x4 and the manx. Looking for an agent to get a quote.

Lindsey Lane
Insurance Agent
Call or Text: 425-238-7173
Lindsey.Lane@libertymutual.com

 

[jginsandiego]

Lindsey Lane
Insurance Agent
Call or Text: 425-238-7173
Lindsey.Lane@libertymutual.com

Thank you 

 

[HEADINJURY]

Definitely one of the smarter dudes here. But if I have to choose who’s going to design my “Off-road” vehicle, well that vote goes to RG and his pedigree of how a proper off-road race vehicle should  be set up. Like the video I posted earlier, you have book smart geometry (Rockwood)and then there’s off road geometry. (RG) Both are good but each have their place. 

Yeah RG knows how to set up a car for a Professional Driver, but what about all the Jacks who will complain the suspension is too stiff. (The Novice drivers, the 80% percentile) That's because your right foot is too light on the pedal. Very difficult to make a happy medium for novice and pro drivers.  A race car is a waste if you can't drive it to it's full potential. Of course unless you wanna look good at the parades at the drags, olds, swingset etc. their will be more than few trailer queens out there. 

Looks like Ed the suspension will be swamped dialing in those Speed UTV's for the different range of customer needs and wants. 

I also think that a lot of people don't realize this is basically a race car and will take race car type maintenance and BUDGET. NOTHING that's built for racing is Bulletproof in any way. It will be costly to own one and run it to it's full potential. It's way outta my league. LOL 

 

[Kat-A-Tonic]

I think he told us about is automotive background. 

Here I thought setting up my kid's r/c buggy for racing was a mind "F", you guys are doing it with SXSs.  LOL!

P.S. - Where is @Lord of the Dunes when all this technical talk is going on?  He likes to talk shop.

Nobody has brought up double shear in a while?

 

[Rockwood]

Damn, they should hire you! You know everything. How many suspensions have you designed?!

Have fun with your front trailing arms!!

LOL.  Front trailing arms are better than A arms.  They don't have jacking moments, are stronger, and don't have roll centers all over the place. All those links just break.  :biggrin:

Either way, talking about this semi-trailing arm setup like it solves everything is a misnomer, and anyone who knows a bit about suspension design should know that you can't point at one thing and say "mine's better".  The trade-off is there in all systems.  You know the geometry, probably better than me, it's not all roses with semi-trailing arms, especially ones with a bunch of pivot in them to get the roll center low.

Definitely one of the smarter dudes here. But if I have to choose who’s going to design my “Off-road” vehicle, well that vote goes to RG and his pedigree of how a proper off-road vehicle should  be set up. Like the video I posted earlier, you have book smart geometry (Rockwood)and then there’s off road geometry. (RG) Both are good but each have their place. 

I agree.  I'm not saying RG's suspension sucks, just bothers the bajeezus out of me when complete bullshit marketeering like Robby's statement of "there's zero possibility that a 5 link is better than a trailing arm, side loads lift the car and the track width changes 10" and it rolls.  This is the absolute worst design you can have for lateral load.  You also get a ton of tire scrub" happens.  Please.  That statement is just unnecessary and incorrect.  

Where's the back picking up?  Where's the "extreme jacking" and 10" of track width change?  That statement is dumb dumb dumb dumb dumb and is almost completely incorrect.

Are there problems with Popo/Can Am/whoever else suspension geometry?  Abso-f-ing-lutely.  Is a semi-trailing arm better?  Uh, I'm sorry, but no.  A 5-link is what you make it.  

The above statement is one of many he makes, and it's my primary beef with him.  Dude, we get it, you like your design.  You think it's better.  It very likely is.

 

[ANGRYBUTTCRACK]

Team Polaris … NOT… 

abc

PS. The Black One has ALL Polaris stickers removed.. but The Orange One is pure SPEED colors, can’t remove the Joyner stickers without losing the ‘look.’

Team SPEED via Polaris.. now we just need a shot of it on its lid  to make the case for his geometry… maybe this weekend.. my brother-in-law is driving Orange, I get Black…

:rofl:

 

[michael.gonzalez]

16 minutes ago, Rockwood said:

LOL.  Front trailing arms are better than A arms.  They don't have jacking moments, are stronger, and don't have roll centers all over the place. All those links just break.  :biggrin:

Either way, talking about this semi-trailing arm setup like it solves everything is a misnomer, and anyone who knows a bit about suspension design should know that you can't point at one thing and say "mine's better".  The trade-off is there in all systems.  You know the geometry, probably better than me, it's not all roses with semi-trailing arms, especially ones with a bunch of pivot in them to get the roll center low.

I agree.  I'm not saying RG's suspension sucks, just bothers the bajeezus out of me when complete bullshit marketeering like Robby's statement of "there's zero possibility that a 5 link is better than a trailing arm, side loads lift the car and the track width changes 10" and it rolls.  This is the absolute worst design you can have for lateral load.  You also get a ton of tire scrub" happens.  Please.  That statement is just unnecessary and incorrect.  

VW beam cars have front trailing arms. Why don't modern Class 1 buggies run them?!

Oh yeah....

 

[Rockwood]

VW beam cars have front trailing arms. Why don't modern Class 1 buggies run them?!

Oh yeah....

Yep, it was a joke.

Multi-link seems to be doing okay though…

https://www.utvunderground.com/guthrie-takes-second-overall-in-polaris-rzr-pro-r-at-best-in-the-desert-silver-state-300/amp

Good thing he didn’t subject that rear suspension to “side loads”. At the speeds he was going, might’ve made orbit. :biggrin:

 

[1HasBeen]

Knee Action suspension FTW!

 

[CampfiresNbrews]

1 hour ago, Rockwood said:

LOL.  Front trailing arms are better than A arms.  They don't have jacking moments, are stronger, and don't have roll centers all over the place. All those links just break.  :biggrin:

Either way, talking about this semi-trailing arm setup like it solves everything is a misnomer, and anyone who knows a bit about suspension design should know that you can't point at one thing and say "mine's better".  The trade-off is there in all systems.  You know the geometry, probably better than me, it's not all roses with semi-trailing arms, especially ones with a bunch of pivot in them to get the roll center low.

I agree.  I'm not saying RG's suspension sucks, just bothers the bajeezus out of me when complete bullshit marketeering like Robby's statement of "there's zero possibility that a 5 link is better than a trailing arm, side loads lift the car and the track width changes 10" and it rolls.  This is the absolute worst design you can have for lateral load.  You also get a ton of tire scrub" happens.  Please.  That statement is just unnecessary and incorrect.  

Glad you went back and redacted your last comment. Your inner BUFF was starting to come out. And you know there’s absolutely no place for that!!!

 

[DTA]

.

 

[Rockwood]

Glad you went back and redacted your last comment. Your inner BUFF was starting to come out. And you know there’s absolutely no place for that!!!

Yeah, came off stronger than I intended when I re-read it. Either way, statements like I quoted from that video are a large reason why there’s so much controversy around this car. I’m honestly rooting for this car, his engineers worked super hard on it, and it shows. Problem I have is the engineers at his favorite targets also worked hard on their product. Shitting on them like they didn’t have a million choices to make is flat wrong. Let the car do the talking.