Boys Bike

[Mr-H]

My grandson (10 yrs old) has a BMX bike. It has become incredibly hard to pedal. It seems to be fine when no weight is on the bike - the pedals will turn very easily - but when it is being ridden it's difficult to turn the pedals. it's not binding brakes or anything like that, it seems as though the problem is somewhere between the pedals and the back wheel (it's a single speed bike so no gear linkage is involved). Any ideas ref. what might be the problem please, folks?

[bookbinder]

Check the chain tension. It might be too tight.

[Mr-H]

Bike was in for a new tyre and front brakes - collected it yesterday. Surely an overtight chain would have been noticed?

[Clanad]

Not necessarily... If the nuts on each side of the rear axle are a little loose the back wheel will move rearward when weight is applied... as when the boy sits on it and over stretching the chain. Turn the bike over on its seat and handlebars and tighten the nuts while assuring there's about 1/2 inch "sag" in the chain.

[joggerjayne]

Tyres too soft?