Thinking about building my son’s next bike using some of my old bits and a frame and wheels Iv picked up only think is he 3 1/2 Years old any one else done this or is it me being crazy

Not sure what you would have in terms of contact points that a 3 1/2 year old would fit and/or could reach?

It’s a lovely idea if you’ve got the bits or can adjust them to fit little hands/arms/legs/bottoms.

I’m waiting till my lad gets to 26″ wheels and then I will upgrade my bike and give him the old tatty bits have a great time building up a nice frame with him (if he wants to)

is it me being crazy

Yes, don’t bother till he gets to 24″ wheels at about 7.