I bought a used GT power series expert for my 8yr. old, 4 feet 4 inch son. I'am now realizing it's probably a little to big for him. Insted of buying another bike or frame what are your opions of changing the stem to a "0 offset" and lower jr. size bars to shorten his reach?

Thanks

What's the top tube length? 19", 19 1/2", or 20"?

Center of head tube to center of seat tube.

Center to center is 19.5. I checked the stem and it's 45mm center to center. I'm not sure the best way to check the rise on the bars but when you flip the bike over it measures 8" inches from the gound to the center of the of the bar where bolts to the stem.

Let him ride the track with someones jr sized bike and see if it feels that much better for him. If he is new to the sport I say just let him run it and he will have grown into it by next year. I think it is worse for a kid to be on a bike that is too small, then one that is too big.

zero offset stem and lower bars might do the trick. Also, does he look like he's chopping when he pedals or are his legs spinning in smooth circles? I know most experts come with 165 cranks, which may be a little long for a kid that's 4'4"

My opinion would be to get him on the right size bike. You bought the bike used so you should be able to sell it for a similar amount. It's not just changing the stem and bars to compensate. Cranks will be too long and the rear end will be different as well.

I did change out the cranks to 155's and the gearing to a roll of 52.85 (37 front & 14 rear on 20x1 1/8)...all with used parts of course. Because were getting close to the end of the season here in the midwest...I think I'll keep an eye out for a nice used junior, and if not, we'll see how much he grows over the winter and go from there. Thanks to everyone for all the great advise!