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3racing Cero Ultra V1 & V2

Old 12-23-2023, 04:20 AM
  #766  
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Originally Posted by TheBeave
What's the trick to keep the upper wishbone spacer from cracking and breaking? I just went through $10 of them trying to put 2 on. Do we need to heat them up or what? Or is there a better alternative?
Just be mindful that there are two sizes including the "C" clip (if building the 2.0 only). The larger one is for the lower arm knuckle pivot. Knowing that there shouldn't be any issue putting the kit together.
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Old 12-23-2023, 07:55 AM
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Originally Posted by TheBeave
What's the trick to keep the upper wishbone spacer from cracking and breaking? I just went through $10 of them trying to put 2 on. Do we need to heat them up or what? Or is there a better alternative?
Upper wishbone SPACER? like the little plastic clip on the pivot bushings? Don't slide them on like a c clip where they open all the way, spiral them on, like put it on top of the bushing with one end of the C under the bushing pressed in and then walk it around, it ends up opening the C a lot less.
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Old 12-23-2023, 08:43 AM
  #768  
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Ran my cero ultra 2.0 (USGT) on our small black carpet track to try and dial in initial setup and these are my findings. First, executive summary, first lap with kit setup, 1.5mm front 2mm rear droop over ride height, 2 degrees camber, 2 deg rear toe, and 37.5 ae oil was already on pace with my old 2k18 car on the same track, in fact, very first lap I drove that wasn't a "get the tires stable" lap was nearly my fast lap with my old car. After the setup changes I made, I was running 2-3 tenths per lap (on a high 9 second track) faster than the old car. Here's what I did and my thoughts.

First things first, the venom body I have on this car right now I absolutely hate. It was my old body on the old car and I wanted to keep things the same to make a fair comparison, but I hate the body and have a new seven20 ready to be painted. The venom body is just too aggressive and inconsistent--it flexes too much and is just a handful.

The first thing I noticed was this car has WAY more on power steering out of the box, which, isn't something I find myself in need of in general, and it also just floats through corners, but like most touring car setups, I find myself trying to calm the front down while maintaining the ability to carve our small infield corners up. My first change was to go to white front springs. This did the trick. I then tried moving to yellows in the rear to see if softer overall was better. Car was slower. In fact it was slower with just the front springs being softer, but it was WAY easier to drive, but with the softer rears, it was .2 slower, so that change was a no-go, and I went back to green rears.

Next I tried changing shims under the upper front wishbone inside to improve the corner profile--the car was waiting on steering to come in as I was trail braking. First I tried lowering the arm (raising roll center, adding camber gain) and it made the car more edgy and didn't add the steering where I wanted it, so I tried go the other way and went to 2mm under the front upper arm and that really rounded out the corner profile on our small track. Turns out this was the right direction, and that makes sense given that it lowered the front RC and removed a little camber gain, which really smoothed out the responsiveness up front and also caused a lot more steering to come in as the car slows down for the small corners. While the RC change is surely responsible for the smoothness increase, I'm not sure if the steering came from less camber gain or the RC, or both! I know on my 12th scales, removing caster really helps on this track so perhaps it was camber angle in the corner. Regardless, it was better, and now I know which direction the front wants to go.

The car was reliably putting down 9.7/9.8 at this point, which I knew 9.5 was possible as I've seen the awesomatix cars do it, but I was pleased that I already was hitting my old car's hero lap on every lap.

Next I focused more on the rear, seeing if I could get the rear to free up reliably. I tried a few things, mainly increasing shock angle and lowering rear upper wishbone inside. In the end, the shock angle change actually locked the car in more on power and I didn't like it, but the RC change in the rear (raised the RC) caused the car to rotate more in the corners. Car was consistent 9.7 with occasional 9.6. Score, but I could tell there was more, and more steering angle at the radio was just adding inconsistency.

Next thing I thought was since I lowered the front RC and it smoothed the car out, perhaps I can go back to the stock yellow springs and it will still be smooth." This was the case, and it immediately removed .1 from laptops overall. I hit one 9.5 and was hitting 9.6 as my top 5/10 average. Car was fast AND nice and smooth, but the rear was still locked in more than I wanted, so I did the needful and removed camber from the rear (now at -1) and boom, hitting multiple 9.5 reliably.

So, in conclusion, -1 camber in rear, roll axis change front to rear (lower front rc, higher rear), this is where I ended up. I told myself that the first time out with the car I was going to just play with shock spring, shock angle, camber, RC/camber gain if I get to it. I try to setup my cars for -2 camber so I can remove grip from one end if I need to, so I'm not super happy being at -1 in the rear, but our track is full of small corners so perhaps that's a good thing so I can add grip at the larger lower grip track I also go to.

My feeling is that I need to also try changing RC front/rear in another way besides the inside upper wishbone link, such as at the arm pivot or hub, in order to try permutations of RC vs camber gain to see which the car is really liking. I also feel like the rear swaybar could go to 1.2 instead of 1.1, and I've seen people do that, so perhaps that's an even better option than the rear link change I did.

I'm under no impression that the setup is done. I want to try ARS changes as well as mess with bump steer and rear sway next, but my initial goal of getting the base "standard settings" in the ballpark is done, and the car is on pace now with the other current gen cars at my track, and faster than my old car, so all in all, good day one.

Also, my 2 kids are getting cero ultra v2 kits for christmas, so I had to figure out a good base setup Dad's job is now done.

Last edited by Razathorn; 12-24-2023 at 10:56 AM.
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Old 12-23-2023, 01:55 PM
  #769  
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Originally Posted by Razathorn
Upper wishbone SPACER? like the little plastic clip on the pivot bushings? Don't slide them on like a c clip where they open all the way, spiral them on, like put it on top of the bushing with one end of the C under the bushing pressed in and then walk it around, it ends up opening the C a lot less.
Zackly! When I swapped the plastic hubs for the aluminum ones I was also swapping in the 3Racing aluminum chassis at the same time and installing 4mm wheel hexes for VTA. I just carefully walked those plastic c-clips off in a circular fashion. Reverse the process to install them. I've done this several times now on my Cero Sport and haven't snapped one yet.
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Old 12-25-2023, 05:38 AM
  #770  
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My anti rolls bars from my Yokomo YZ2 fit nicely on My Cero Ultra Ace. Opens up the options a bit

Last edited by DIME:RC; 12-25-2023 at 06:15 AM.
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Old 12-25-2023, 08:47 AM
  #771  
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After almost eight years, I have decided to go racing again at 13.5 blinky. Cero Sport 5/5 looks very promising with some upgrades. Cero Ultra is not an option for me. I have read all the thread for spares and weak parts. Please check my list:

SAK-C141 Knuckle since stock plastic knuckle is weak.
SAK-C104/V2 Spare chassis for outdoor. I will use the plexi chassis indoors.
SAK-C130 Ultra upper deck. Spare and for more flex outdoors.
SAK-C175 Spare bumper and body posts
SAK-C133/V2 Anti-roll bar set
SAK-C105/V3 Ultra front lower graphite wishbone
SAK-C134 Ultra front upper wishbone
SAK-C106 Ultra rear lower graphite wishbone
SAK-C149 Ultra rear upper wishbone
SAK-C140 Ultra knuckle plate
SAK-A577 Front belt

SAK-A576 Rear belt

Thanks for reading
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Old 12-25-2023, 12:27 PM
  #772  
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the thing about the sport is how easy it is to sink another 150 or so on it, half of that on the knuckles alone. i have a feeling that with the options u list are gonna take u well over 300 and the v3 rear lower arms is gonna make the wheelbase longer than 257mm
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Old 12-25-2023, 12:59 PM
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Originally Posted by 2dialed
the thing about the sport is how easy it is to sink another 150 or so on it, half of that on the knuckles alone. i have a feeling that with the options u list are gonna take u well over 300 and the v3 rear lower arms is gonna make the wheelbase longer than 257mm
258-260mm wheelbase is good for me. Are plastic shocks good? Did any of you break a surprising part?
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Old 12-25-2023, 02:55 PM
  #774  
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i don't have the sport , its just the direction your heading your better off with the ultra. what surface are u running, on outdoor with berms instead of boards i think the sport would be pretty good if u don't tangle with other cars
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Old 12-25-2023, 06:12 PM
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I started with a sport. in hindsight I would just get the ultra. the plastic bits just break to easy. and as posted above the upgrades add up quick plus they are constantly out of stock. so you get to pay for shipping 12 times.
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Old 12-30-2023, 06:54 AM
  #776  
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does any versions of this chassis come with metal hubs?
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Old 12-30-2023, 11:42 AM
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Originally Posted by hotrod306
does any versions of this chassis come with metal hubs?
they have aluminum hubs only the “sport” comes with plastic hubs
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Old 12-30-2023, 01:29 PM
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so has anyone tried v3 rear lower arms or shock towers on a v1 chassis? . i guess it would be positive rear caster and need less bumpsteer washers. are people with the v2 chassis going with harder springs with the shocks laid down more. i see stephan and marcos went a little harder on springs than what they were running
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Old 12-30-2023, 08:14 PM
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Originally Posted by 2dialed
so has anyone tried v3 rear lower arms or shock towers on a v1 chassis? . i guess it would be positive rear caster and need less bumpsteer washers. are people with the v2 chassis going with harder springs with the shocks laid down more. i see stephan and marcos went a little harder on springs than what they were running
I’m running mugen springs they are a lot softer than 3racing springs
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Old 12-31-2023, 05:57 AM
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Originally Posted by 2dialed
so has anyone tried v3 rear lower arms or shock towers on a v1 chassis? . i guess it would be positive rear caster and need less bumpsteer washers. are people with the v2 chassis going with harder springs with the shocks laid down more. i see stephan and marcos went a little harder on springs than what they were running
I tried assembling that and without the shoch towers it is a hot mess. I think the number is 4mm. That is the offset on the lower V2 arm pivot. The V2 car moves the bulkheads that much forward and the arm mounting points to the chassis. Because of that the rear shock towers are revised too so if you don't change them the shocks are at a big angle front to back. The V2 also uses the front upper arms, again because of the 4mm offset. If you don't use them the rear caster is insane and surely not workable. When I tried the assembly and everything was so out of whack I just returned it to original.
I do have front uppers on the rear though for a little caster back there. The car is smoother that way and the V2 has that same caster.
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