My 9 year-old son wants to race BMX. Last year, before I knew he wanted to race, I bought him a GT Mach One Pro based on what the LBS guy told me, to "grow into". Riding around the neighborhood, it's fine. But my son is small for his age, and after watching him ride his bike at the local track (Chandler BMX), it's apparent that the bike is way too big for him. He looks strained riding it, and after a few laps, his back hurts. He's all of 4'3", 54 lbs.
His skill level is Novice, so I don't want to buy a $400+ bike at this point, but I do want to get him on something that fits right. Problem is, I don't know what "right" is, and after the last LBS selling me a too-big bike for him, I'm not too trusting of the shop guy who just wants to move a bike that day. If anyone can recommend a good shop and someone knowledgeable to talk to in the Chandler/Phx, Az area, that would be great.
Can I make this bike fit him with a different stem/handlebar setup? Is it worth the effort/expense? Any advice or pointers to stuff already written on the subject of fitting a rider to a BMX bike would be much appreciated.
2008 Kink Transition with upgrades, 2007 Haro Thread 1 with upgrades.
i really like the intense's they have really good reviews also.
I'm not sure if that would be the right size, but there is around 5 more sizes, so just take a look at those. There around 300-350.
At 4'3" your son should be on probably a junior, generally speaking that equates to a top tube length of 17 or 18 inches. My 9 year old races an Expert sized frame but is 5 inches taller. The bike you have is a Pro sized frame, that is the size that most average sized racers switch to at about 13.
Trying to fix up the current bike would not be a great idea. The top tube is too long so you would need to swap the stem and/or angle the bars back, which will negatively impact the handling. The bars are likely too high and the cranks are for sure too long. At his height he should probably be on 160mm cranks and that bike has 175's. Even if you made changes to get the fit closer you would still end up with a very heavy bike for a young racer.
Around our tracks (Vancouver, Canada) there are always lots of used Juniors, I would go that route if I were you. If he sticks with it then get something new or better when he needs the next size. I took a quick look at Craigslist for Pheonix and see that there are a number of race bikes for sale, including what appears to be a Redline Junior for 150.
150.00 is a reasonable price but a Micro usually has a top tube length in the 16 inch range and really low rise bars. Micro's and Mini's are meant for really little riders, your son would be at the top end of the height range for that frame so you would likely get little use out of it. He is probably going to be most comfortable on a junior.