I have had bb's in my 35" BFG's for about 4 months and 12,000 miles now, i and i have had some problems, but for the majority of the time it works fine. Although i think that these problems, outweigh the benifits...
If i brake hard down to ~15-25mph or under, and then resume acceleration, or, Hit a bump or even a gutter ~15-25, and then accelerate or, Turn Left from a stop, esp. when i shift from 1-2 (5 speed), Basically if they dont "set" right, during their "setting speed", they can get out of balance, Really Bad, and cause the same effect as Severe "death wobble". Basically when they get "out of balance", the bb's can all gather in the same spot, and then the wheel(s) become, essentially a "vibrator"... and theres No speeding out of it, so dont try that... i experimented with steel, rubber balls, and now i have the airsoft .12's . i also played with weights, now i have 12oz in each, soon 0.... i would rather just get them balanced as best as they can...
It happens alot ( ~100+ times in 12k), and im used to driving a "not a daily driver" everyday.
oh, and dont blow a tire! on the trail, or the freeway, (Just think "shrapnel")
Not to mention the sounds it makes, just look at the person next to you when you stop next to them, I still lmao all the time!!! even now just thinking about it!!!!