My guess is they're thicker than the advertised 25mm then. I've tried several brands that are all 25mm (measured) and they all fit.

with the 4.1 tower the gensace 40c and 50c fit perfectly in my buggy.

with the 4.1 tower i can run the battery in full forward or full rear position.

with the old b4 tower if i wanted to run the battery in the rear position it was really tight, but would work if the rear of the strap was put in first.

No problems here with Gens Ace Lipos on my FT B4.1.

I just got a FT B4, the carbon rear tower would not work with a ace gen 4000. The carbonfiber battery strap seemed like it was stressed to much. I replaced the rear tower with a reg plastic b4 tower and it works perfect now. FT thumb screws only way to go for hold downs.

odd, all i run are gens ace 40c & 50c 5000 mah packs in my FT b4.1 and they fit perfect.

It fits fine, it just doesn't slide under the shock tower.

I just got new Gens Ace 5000 40c batteries 2 weeks ago, and they fit my 4.1 flawlessly.

It may be new vs old then. This one is like 7 months old. They've done some case revisions in the past month or two.

TBird , use .030 shims under rear tower and make the extra height you need to fit the new Li-Po...


or use the 4.1 tower

That's a backup battery. The batteries that are run in the car fit fine in it...and it IS a B4.1 tower :P

I was putting the rear of the strap over the tower on my B4 when using the Gen 5000. It held just fine. They fit just right in my B4.1.

Hello, guys. Ive surfed back a few pages and didnt find anything on the subject. So id figured I would ask this question. I race on a offroad carpet track with my b4.1 factory team (which came with a ball diff) Is it possible as a tuning option to install a gear diff in this buggy? This carpet is tough on ball diffs. If it is possible, what parts are needed to complete this job from start to finish? New trans? Sc10 gear diff? Id really like to give it a shot but im not sure at all what parts to get. Thanks, Lee...

SC-10 gear diff kit is all you need. Confirm that your outdrive bearings are 10mm X 16mm.

Wow thats it??? my existing transmission will work? Cool !!! Are there better diffs out there ?( aftermarket)

The AE gear diff. is your only option