With the Bestrider Pump Pro 20 kids bike in hand, I am now able to study the stock components and also the original bike geometry and dimensions.
I did the same geometry study for the Bestrider Pump Pro 16, although it was not as detailed as this one.
Wheelbase is about 841 mm, which is longer than 700 mm on the 16 inch version.
Rear chain stay length is 330 mm, longer than 273 mm on the 16 inch version.
Standover height is about 520 mm, compared to 450 mm on the 16 inch version. Make sure your kid's inseam is longer than this number.
Handlebar width is 610 mm, which is even wider than the 560 mm of the 16 inch version.
Handlebar height from the ground is 810 mm, which is too high for a kids bike.
Although the rest of the bike is designed for kids, somehow the handlebar width and height is not. It is way too wide and high for kids. It is one of the few design problems with the Bestrider Pump Pro series, but it is not a big issue since this can be changed rather easily.
Stock tire diameter is 500 mm, which is pretty standard for 20 inch 406 tires.
Tire width is 44 mm, which is good for comfort and off-road riding. However, will be changing to narrower, slicker tires for pavement and PCN riding.
Huge amount of tire clearance at the front fork. Not sure why the distance between the tire and the fork crown is so big. Same design as the 16 inch version.
Still lots of tire clearance at the rear as well, even with these rather big tires.
Crank arm length is 127 mm, which should be a good fit for this 20 inch kids bike. On the 16 inch version, the crank arm length was 102 mm.
Verified with actual measurement.
Narrow wide chain ring has 32T, which seems kind of small, even for kids bikes.
Rear frame OLD is 135 mm, which is a typical width for disc brake rear wheels, although this is not a disc brake rear wheel.
Front fork OLD is 100 mm, which is also a standard width.
Weight of Bestrider Pump Pro 20, excluding kickstand is 7.6 kg. This is a very good weight!
If we add the weight of the lightweight kickstand, the total weight would still be slightly less than the claimed weight of 7.8 kg.
This has to be one of the lightest multi-speed 20 inch kids bikes that I have seen. Most other kids bikes weigh a lot more, even with a simple single speed setup! Bike weight is very important for kids bikes, as they will need to handle a bike that is a large percentage of their own body weight.
Stock setup has lots of spacers on both sides of the bottom bracket adapters.
Bottom bracket frame width is a standard 68 mm, English threaded. Will be easy to swap in another standard bottom bracket.
Most of the frame geometry and component dimensions seem to be well sized for 20 inch kids bikes. With the exception of the handlebar that is too wide and too high, all other areas seem to be well designed.
