Posted up on Amain:

https://www.amainhobbies.com/yokomo-...2c31a/p1445873


Personally if I was going to buy this, I'd want it as a kit. Also think it could get better adoption if the price was maybe closer to $500-$600 range since you do have all the options included and the regular car is $410, makes the included option items have more perceived value. But if you are wanting an all optioned CAL3.1 that is also prebuilt, here you go.

$765, holy ****!

I am EXACTLY the person this kit is for, but at that price, uh... wow.

Does anyone know if there is an blank setup sheet for that Fuzion shock tower? I cannot one to download.

Looks like folks are just making a note about the fusion tower... what would want to see on the sheet about it? Also, when you use the fusion tower you use the lower mounting option for the swaybar right?

Looks like an all option YZ2 3.1 based buggy is on the way that isn't prebuilt? Not sure though if this is including all the carpet stuff too, or if a CAL style one will be on the way as well?

It was announced on mibosport website long time ago. There're cal and dtm versions, all optioned with some setup changes

Just this one lol 🤣

No, this apparently different which is why I posted it versus the other 2 full option prebuilts.

It sounds like this particular model may include the stuff from both DTM and CAL lines, but with 1 chassis versus say both out of the box.

OH! You're right. But still sounds a bit odd. Looks like a non sense release, at least for EU and USA markets

Right now need a bit more info, in comparison to the other all option prebuilts, this at least to me makes alittle more sense than those since being all option and a kit I would see racers being interested in this and buying versus someone who is into RTRs basically. Think of it like the Factory Edition releases AE used to do, or, maybe Losi Elite 4wd buggy release

Little tip for today.
Use the angled ballcup included in the kit to avoid the steering link interfering with the shock action.
This change won't affect any other ackerman setting but you will need to readjust your front toe in/out.

How is the hit on the wheel for the inside tire on the turn (basically the opposite direction in your picture)?

By the way nice mod using a button head screw with the nut on the back of the tower! That should help with tracks that require you to trim flush the screw to the nut on the front to protect the carpet, I gotta give that a look see.

So something that appears to be an option for tuning for more rotation has been going back to the S3 a-arms from the CAL3 with shorter driveshafts (68mm) though I wonder if you could still run the 69mm and pull the shims that are on them which I think are about 1mm in shims?

I have also seen some recent setups using the YZ4SF2 rear hubs but with stock L5 a-arms on the CAL3.1. I am assuming this also narrows the car on the rear but of course keeps the same shock positions relative to the a-arm versus going to S3 a-arms but stock rear carriers.

Has anyone tried the two and has information on how they felt in comparison to each other, as well as in comparison to the stock car rear hub / arm setup?

The pic was taken in that angle to show the turnbuckle itself.
Here's the comparison.

Stock. Turnbuckle touches the spring.


Modded. Turnbuckle is not able to touch the spring.


Yup. Saves carpet from tearing, saves screw from bending and makes shock tower hole changes easier. Give it a try!

69mm driveshafts do come with 2x0.5mm shims for a total of 1mm.
Not true for S3 arms.

What are the handling differences between the 73 and 75mm arms.
Brief explanation from RogerM (thanks!)

The arm length effects the roll centre and more significantly the roll centre migration as the car rolls in the corners.

Shorter rear arms will encourage more tire loading so more grip as the car rolls, great for lower grip surfaces but on high grip surfaces they can stall the rotation mid corner costing corner speed. They can also make the car feel more reactive which is good when a low grip level makes the car feel less reactive so making it harder to place in technical sections.

Long rear arms the opposite, car will rotate more freely for more corner speed but won't generate as much side-bite so mid/late corner will be reduced. Make the car feel naturally lazier which is great on high grip surfaces as it makes the car easier to drive overall.

So the long Vs short rear arm is just like the flat Vs gullwing front arm, all about the grip level from the surface and how technical the track layout is.

SF2 rear hubs do narrow rear width a lot. probably needs some different driveshafts or axles. Is your car lacking something?

Looks good will give that a look see since its not impacting the wheel.

When you say Not true for the S3 arms can you elaborate if you mean the 68mm bones don't come with shims or do you mean its not true you can pull the 1mm of shims total and still run a 69mm bone?

Is this basically what is being described here:



More so just looking at comparison between narrow a-arm usage versus narrow hubs.

I meant the S3 arms would cost the car corner speed for gaining some traction.

Just for clarifying.
- 68mm bones do not use shims and are used with S3 arms
- 69mm bones do use 2x0.5mm = 1mm shim and are used with L5 arms.
- S3 arms are +-81mm long. (+-73mm between holes)
- L5 arms are +-84mm long. (+-75mm between holes)
- L5 most inner shock mounting point is close to second outer position on S3 arm.

That said, you could probably run those 69mm bones with removed shims if you go with the widest pills available




Not much to tell here.

- SF2 hubs are 13mm wide
- CAL3.1 hubs are 17mm wide.

Looks like SF2 hubs do not use the spacer between bearings, so the inner bearing sits closer to the outer bearing.

- On CAL3.1 hubs the hex sits 4mm wider than SF2. That would be a total of -8mm on rear width from my measurements, but the bone needs a shorter axle

just FYI there is a spacer on the rear hubs, if I recall correctly I think its the same between the 2wd and 4wd cars now, pic from the wheeler manual::