Speed UTV

From the video.

Scrub radius: exactly centered isn’t a good thing. Slight offset inside or outside (depending on rear or front steer) helps for more positive and stable steering feel. You don’t want a lot, but you want some or you end up with some oscillation in the tire tread as it encounters imperfections in terrain and the steering has a wandering/uncertain feel. Either way, I don’t think homeboy’s wheel/tire package is stock, so not sure why they’re comparing scrub radius there.

Longer arms on the Speed will be nice. I don’t think there’s a huge strength advantage in heims (“monoballs”) on the ends of control arms compared to ball joints. Stronger? Sure, since the heim’s shank is physically larger. But it’s still a compromised design since it still has the threaded shank of the heim as a weak point. No trophy truck uses heims there.

$7-800/arm for boxed arms? Can’t you get a complete set with uniballs for like $2k?

Overall CoG looks a lot better.

Visibility: I highly doubt the 1’ closer FOV matters at all. Other than rock crawling, if you’re looking 10’ away at the ground, you’re gonna die. In the rocks, that 1’ of extra memory won’t matter. Cool they looked at it, but meh. 

Interior looks clean. Digital dash on the Speed is cool. Glare might be an issue, but lots of function there. Anyone know if it’s waterproof?

Roll centers: we’ve killed that discussion. He does say his outer pivot is lower when measuring ground clearance, then says the inner is lower. On the Polaris, the wheel can’t tuck under the vehicle unless it’s broken. When cornering with enough force to roll a vehicle, you won’t have the outer suspension unloaded like that anyway.

Not sure how semi trailing arm is a decade ahead of multi link, but okay.

Negative camber at full droop is good? With body roll, the contact patch on the unloaded tire (drooped) would be smaller and it would be harder on CVs.

He forgot some measurements:

Engine displacement :bag:

Suspension travel

Bumpsteer

Live valve?

In the end, this looks orchestrated to show where his is bigger. The existing marks where they measured things out reminds me of movies where you can see the previous take’s skid marks on the road.  Color me surprised. 

 
Last edited by a moderator:
Negative camber at  droop helps with CV angle. It doesn't seem to be affecting overall handling from what I see.

suspension travel is snake oil. gaining suspension travel at the expense of horrendous track width change, high roll center, bump steer, etc is not a net gain. You can achieve the same goal, sometimes better, with less travel.

Bump steer has been brought up before. Speed wins. There is practically none.

 
Bodywerks said:
Negative camber at  droop helps with CV angle. It doesn't seem to be affecting overall handling from what I see.

suspension travel is snake oil. gaining suspension travel at the expense of horrendous track width change, high roll center, bump steer, etc is not a net gain. You can achieve the same goal, sometimes better, with less travel.

Bump steer has been brought up before. Speed wins. There is practically none.
Click to expand...
Negative camber makes for worse CV angle, not better.

Track width change, sure, that’s worse, if it matters that much. Roll center calcs have been done. They’re about the same. Does the Pro R have a lot of bumpsteer? Did anyone measure? I don’t see a Shock Therapy kit, but if it does, sure.

Suspension travel isn’t snake oil, it absolutely matters. Useable that is, not the bullshit claimed in the past by SxSs and buggies alike where some of the travel is after the frame cases. 

 


I only said negative camber because you said negative. It actually goes from like 2-3 negative at ride height to around 1-2 positive at droop. This is one of the only compromises of the trailing arm design, since there is virtually no track width change and plunging cv shafts needed to be used.

Agree that 'usable' travel matters. all current rzr's, x3 and pro/turbo R chassis' bottom before the suspension does. And gaining suspension travel on the droop side, again at the expense of 10-12 inches of track width loss, bump steer, etc. begins to negate the travel gain, just to be able to say you have the most travel in the industry, IMO.

22" useable travel is quite good for a sxs, which is what the Speed has. Polaris advertises their suspension numbers backwards, I believe. They claim 27" useable and 22.5" 'wheel travel'. I believe the wheel travel is their actual useable and the extra 4.5" might be useable with a bigger tire, or when considering body roll in a hard turn. 

Surely you've seen rzr's and can ams on their lid numerous times? Have you watched it happen? Sure, there's a driver talent element, or lack thereof that gets them on their lid most of the time, but it's the high roll center and jacking affect of the rear trailing link design that makes it easier to run out of talent. But yes, there are also ways to mitigate it, which is why my rzr has way stiffer swaybars and stiffer suspension.

 
Last edited by a moderator:
Bodywerks said:
I only said negative camber because you said negative. It actually goes from like 2-3 negative at ride height to around 1-2 positive at droop. This is one of the only compromises of the trailing arm design, since there is virtually no track width change and plunging cv shafts needed to be used.

Agree that 'usable' travel matters. all current rzr's, x3 and pro/turbo R chassis' bottom before the suspension does. And gaining suspension travel on the droop side, again at the expense of 10-12 inches of track width loss, bump steer, etc. begins to negate the travel gain, just to be able to say you have the most travel in the industry, IMO.

22" useable travel is quite good for a sxs, which is what the Speed has. Polaris advertises their suspension numbers backwards, I believe. They claim 27" useable and 22.5" 'wheel travel'. I believe the wheel travel is their actual useable and the extra 4.5" might be useable with a bigger tire, or when considering body roll in a hard turn. 

Surely you've seen rzr's and can ams on their lid numerous times? Have you watched it happen? Sure, there's a driver talent element, or lack thereof that gets them on their lid most of the time, but it's the high roll center and jacking affect of the rear trailing link design that makes it easier to run out of talent. But yes, there are also ways to mitigate it, which is why my rzr has way stiffer swaybars and stiffer suspension.
Click to expand...
Polaris uses tire squish as part of their claim of "usable" travel.  Can Am does not use that, but should knock about 1"-2" off their advertised numbers as the frame will contact the ground before you use it all.  LOL!    

My friend measured his Can Am ground clearance at full bump at it was like 3/4" of an inch.

I think majority of the tip overs are from people either screwing around doing doughnuts or getting sideways in 2wd and catching an edge/not knowing how to counter steer when the ass end gets loose.    

If a Speed UTV owner puts it on the lid or side, what is the reason?  

I have driven a Pro R and the crazy track width change is at full droop, which means you are up in the air.   Going through the whoops at 50mph - 75+mph there is no darting and the Pro R is super stable.  I would say if there was bumpsteer it is minimal.   My first Can Am was horrible and scary in the whoops as it wanted to dart all over.  Fixed it with a bumpsteer kit.  

RG can show you all sorts of stuff that is allegedly bad with the Pro R suspension, but when you drive one you will not notice any of it.   The car with the live valve flat out works well.  

I have no doubt the Speed UTV suspension will work awesome.  The Speed UTV is similar in design as the Wildcat XX, but a lot beefier and bigger shocks.  The Wildcat XX suspension works amazing and it is a good SXS, just needed to have a turbo for more fun in the dunes. 

 
Bodywerks said:
I only said negative camber because you said negative. It actually goes from like 2-3 negative at ride height to around 1-2 positive at droop. This is one of the only compromises of the trailing arm design, since there is virtually no track width change and plunging cv shafts needed to be used.

Agree that 'usable' travel matters. all current rzr's, x3 and pro/turbo R chassis' bottom before the suspension does. And gaining suspension travel on the droop side, again at the expense of 10-12 inches of track width loss, bump steer, etc. begins to negate the travel gain, just to be able to say you have the most travel in the industry, IMO.

22" useable travel is quite good for a sxs, which is what the Speed has. Polaris advertises their suspension numbers backwards, I believe. They claim 27" useable and 22.5" 'wheel travel'. I believe the wheel travel is their actual useable and the extra 4.5" might be useable with a bigger tire, or when considering body roll in a hard turn. 

Surely you've seen rzr's and can ams on their lid numerous times? Have you watched it happen? Sure, there's a driver talent element, or lack thereof that gets them on their lid most of the time, but it's the high roll center and jacking affect of the rear trailing link design that makes it easier to run out of talent. But yes, there are also ways to mitigate it, which is why my rzr has way stiffer swaybars and stiffer suspension.
Click to expand...
Negative camber: Robbie said he has negative camber at full droop, not me.  It's in the video and he spends time to pan and show it like a "feature".  This was on the front suspension.

Bumpsteer: Most of the time bump steer exists because it's a tuning tool or a compromise, not necessarily because someone doesn't know how to design things.  You can always zero bump steer, but you do it at the loss of something else (usually negative camber gain).  Either way, he didn't measure this or show it.  I think he should. 

Travel: I think 22" is plenty, but this was a richard measuring contest, so if he was "trying his best to not be biased" it would've measured these things and compared them.  He didn't.  I think he should.

Side note: What's the CV angle at full droop for the Speed?  22" of travel on a 77" wide vehicle seems like a lot of angle for plunging CVs.

SxS flops: I've seen plenty do it.  Hell, I've flopped one myself.  Every time I've seen someone roll a SxS, it's generally because they get it sideways, panic, jam on the brakes, and go for a ride.  I've yet to see some dude bend into a corner normally and the thing just goes over like God was bored...

Roll centers: I did the rough RC calcs earlier in this thread (somewhere before 200?  Dunno) and it's a couple inches above the ground and moves with the chassis as it droops/bumps.  RG's RC stays the same because of trailing arms, but this mainly means more body roll at higher ride height.  If a Can Am's RC is high, so is Speed's.  Neither appear to be a problem.

Jacking effect: this keeps coming up and it's dumb.  Unless the shock breaks, the tire can't tuck under the vehicle like Robbie says in the video.  During cornering heavy enough to flip a 1500-2500lb vehicle, the outside suspension (loaded) is compressed, not drooped, and the control arm is nearly flat (which also increases the shock's resistance to jacking forces since it is angled outwards).  Yes, if you were to magically corner hard with no weight on the suspension (fully drooped) and then the shock somehow also broke to make sure it happens, you'd have a jacking moment with resulting mayhem.  But this is PFM and as real as Speed's CARB cert.  There are no real-world dynamic instances where this confluence of events is going to happen.  Showing the control arm angle at full droop and saying "see! Jacking!" is ignoring how it actually happens.  Full droop means there's no weight on the suspension, which zeros the N part of μ = f/N, aka: mathematical error and no leverage on the vehicle.

2021-Can-Am-Maverick-X3-X-rs-Turbo-RR-ORC.jpg


What's the radius rod angle there?  How wide is the track? Has anyone ever seen a fully-drooped RZR or Can Am flop? Go watch some SxS fails and I'm sure you'll see one land sideways then roll.  Guaranteed the suspension nearly bottoms (or at least gets to ride height) before it goes over.

Either way, re-watch the SSSS footage (pre control arm mount break, obviously) and you'll see the Speed UTV going up on 2 wheels super easily as well:

image.jpeg

Track change: yawn.  It's mainly hard on unit bearings and radius rods since there's always some scrub as the suspension cycles.  Might make for less grip over bumps, but the front does the same, so should mostly balance out.

Again: just build the thing.  Quit measuring wieners and get them in customer's hands so they can judge.

 
Last edited by a moderator:
Sand Shark said:
I think majority of the tip overs are from people either screwing around doing doughnuts or getting sideways in 2wd and catching an edge/not knowing how to counter steer when the ass end gets loose.    
Click to expand...
I would say that a majority of the in the dunes rollovers are when the person doesn't realize it is time to turn out of what they are doing not just keep giving it gas thinking it is going to save itself.

 
So it looks like RG is taking 3 of the race purpose built Speed UTVs to King of the Hammers to race in the desert race.   Be interesting to see how they hold up.

Wonder what he will say about track width changes when the Pro R and Can Ams are on the podium.  LOL!!!  

 
Sand Shark said:
So it looks like RG is taking 3 of the race purpose built Speed UTVs to King of the Hammers to race in the desert race.   Be interesting to see how they hold up.

Wonder what he will say about track width changes when the Pro R and Can Ams are on the podium.  LOL!!!  
Click to expand...
Heading out Thursday to Saturday with Artie!  I take it you will be racing R/C's lol, but when is the desert race for the UTV's?  Never been to KOH so Im clueless, and KOH website is full of racing stuff with so many different classes and races, I thought you can enlighten me sir.

 
JBL said:
Heading out Thursday to Saturday with Artie!  I take it you will be racing R/C's lol, but when is the desert race for the UTV's?  Never been to KOH so Im clueless, and KOH website is full of racing stuff with so many different classes and races, I thought you can enlighten me sir.
Click to expand...
You riding with Artie?  May God have mercy on your soul, LOL.  That was the scariest ride I was ever on when Artie gave me a ride back to camp after I snapped a ball joint.

 
JBL said:
Heading out Thursday to Saturday with Artie!  I take it you will be racing R/C's lol, but when is the desert race for the UTV's?  Never been to KOH so Im clueless, and KOH website is full of racing stuff with so many different classes and races, I thought you can enlighten me sir.
Click to expand...
Desert races start this weekend.  Have some friends racing a 1450 truck.  
 

https://kingofthehammers.com/eventschedule/

Have fun out there!

 
You must log in or register to reply here.
Back
Top