Well lets see...started with a Bolink Eliminator 10, then on to the 10L, then 10LW, 10LS, 12LW, 12LS, EV10, Trinity Reflex 12, HPI 10GW, 12LC, 12L3, Carpet Knife, Darkside 1/12th, and the DB12R through CH12. In several of those I had options to move the battery around and found the car always had bettter grip with the batteries more to the rear. The Darkside car I ran I even had to use the 0 degree caster block to tame down the front. In the case of the BMI cars the battery did move more forward from the DB12R to the DB12RR and gain rear grip...but that was largely due to the longer rear pod giving the rear suspension more leverage on the shock. The difference I notice though might be in the surface. Out here we only run on asphalt and most of those years were on untreated asphalt go grip was pretty low. Though the Darkside and all my BMI cars have ran on very sticky treated asphalt.

I can tell you that even a small change in polar moment of inertia can make a noticeable difference in a 1/12th scale. Not in all corners, but VERY noticeable in some. I did some experimenting with a 4 cell T bar car a few years back. It had a couple different ways of mounting the cells. One holder had them out a bit further, one more in, same fore/aft weight distribution either way. The results:

Most of the track, the car felt exactly the same. But right in front of the drivers stand was a fast right, left, right chicane. Batteries out, the first right was wide open but the quick flip of the wheel to the left would induce double steer and force me to back off. Batteries in, it was full punch, on the line and perfectly stable. And again, this was a very small change in mass distribution. Lower moment of inertia will give faster direction changes and be more stable when making those changes.

Since we are running 1s lipo now, not 4, or 6 round cells.
I should have clarified which 1s lipo car are you running

No matter the surface, my 12r5 prefers more front weight, than rear.
From low grip asphalt, to high grip carpet, the base setup is virtually the same, tires tune in the grip.

Round cells or LiPos I've been hearing that on this forum for years now and personally just haven't found it to hold true. I should have also mentioned the F103 since that went from a round cell to a LiPo and people running those lost a lot of rear grip in the transition. Many people ended up adding weight back on the car to try and get rear grip.

Interesting.
I run a 1s lipo with the F-103 as well.
Have not lost any grip, and noticed an increase in corner entry and mid corner speed.
No setup changes since the 90's on that car

Probably because your running 1s...that is quite a power loss from 6 cell NiMh. Look back through F103 thread to around the time of transition to LiPo and you'll see a number of post on people losing grip.

Also an increase in corner speed reinforces what I am saying...people here are saying moving the battery more forward makes the car more pushy which will decrease corner speed.

I haven't looked into moving the 1s around for the 103, seems good as is.
With a 10.5 boosted it is anything but slow.
Most of the guys I run against in the "Open Class" of the UF1 series are running 2s 13.5 !

But this is a 12th scale thread, so we can discuss F1's elsewhere

C.Andy’s 1/12th scale conversion kit

interesting motor pod

WOW this is a really cool idea. Is there a performance increase? Is this available for purchase or a one off?

It's interesting but it looks like you have to swap shims to change gear mesh. That means gear range will be limited, changes will also slightly change wheelbase and generally be a pain in the rear. No thank you.

On another note, that is a big slab of molded CF in the back of that thing. Very nice. I wouldn't be surprised if we start seeing more and more molded CF parts in the years to come.

The issue i see with molded CF is the difficulty in doing it which will drive up cost. I'm sure this conversion is not inexpensive.

CFR,
Any chance you're working on one for a CRC car?

Not only that but every time you change gear ratio your wheel base changes.

Especially when it could easily be done without the molded CF and keep the costs lower.

I believe I mentioned that.