What size skis for a junior racer?

Question
My son is fairly new to ski racing and thinks that his skis are not the right ones.  He's really pushing to get the right ones this season.

Has:  Dynastar Ski Cross Team, 130. (And he
used to where a size 4.5 boot, now is in a 7!,
so I'm concerned about the old binding fitting
his new boots)

He's 90 lbs and 4'9".

Should we stick with the 130 length?  or go
to a 140 length?  And are we going to be forced
to get new skis considering that the old bindings were set for a much smaller boot?

Any recommendations? I see that Atomic has a line
of racing skis for juniors at reasonable prices.

Thank you!  

Answer
Dear Drena --  

Bad news first, you may have to buy new skis, if a qualified ski shop cannot remount the bindings on the Dynastars to fit your son's new boots.  This mounting is the most critical aspect of ensuring your son has appropriate and safe equipment, that the ski-binding-boot interface is properly setup and maintained.

Next, ski length should be determined by weight, and skiing style, not necessarily by height.  Heavier skiers need longer skis so they do not damp out the camber as easily.  But they can also get a stiffer ski with more camber for the same effect.  The modern skis with the more extreme sidecut allow skiers to use shorter skis to the same end as the longer skis provided in the past --- smooth, stable, carved turns.  

Finally, pick a ski type and length based on how your son is racing.  If he is just competing in giant slalom, get a GS focused ski.  If just slalom, get a slalom ski.  If he is doing both disciplines, get a more versatile ski.  The Dynastar Skicross is a good choice for slalom skiing for a child that's getting tall but is still light, like your son.  It's a quick turning ski with a lot of energy to feed into initiating the next turn.  It's probably not as easy to hold that ski steady and carving through a lot of GS turns, though.  If the Dynastars can have the bindings remounted, you may want to consider them the slalom ski, and think about getting an Atomic ski for a GS ski.

You might look for a ski shop near the mountain where your son races regularly, and see if any of them sponsor a "trade-up" program.  The shop near my hill allows parents to buy equipment, but as their child grows, allows them to trade-up to larger, better items with a significant trade-in value on their old equipment.

Please let me know, if I can answer any aspect of this question in more detail.  Best of luck to you and your son.