On the subject of wheel balance, we often expect the valve side of the wheel to be heaviest, this isnt the case, the way the rim is constructed at 180 to the valve hole there is additional weight , the rim ends are usually located with thin steel dowels to align before welding, the weight of the valve is often less than the join weight.

I never used to bother balancing the back wheel, one day I was messing around with an old pushbike, pedalling it up on the stand in top gear I was alarmed when a 6 inch hop developed at the back end, shaking the whole thing violently, the wheel was true, so I spent a few minutes with solder and balanced it, pedalled up to speed , no hop. Road speed for this would have been around 30 - 40mph. I balance my rear wheels as well now.

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod