My son Collin has an old Arrow Cadet Kart. He is 4’6" and weights 75 lbs. This is his first year and instead of having him go to races we go to whatever track has open practice as often as possible. He’s made great progress this year and his lap times have dropped dramatically. He’s going to run Rookie Yamaha next season.
Our local group president thinks he needs to move up to a sportsman kart and just happens to have one he is willing to trade. It’s an older Kosmic kart.
I was going to wait until his seating position was an issue and we still have another mount hole on the chassis to move the seat further back, and while he’s not event the least overweight he’s he is pushing 80 lbs.
Not sure I follow as the Rookie and Sportsman karts all are on the 900-1010mm chassis with nearly every Rookie/Sportsman/cadet kart being 950mm. Although there are a few 960 & 970mm Benik and Merlin karts out there. Is your Arrow a very short wheelbase kart? If you are running 3-hole Yamaha Rookie you are not at any disadvantage on the 900mm chassis. My drivers absolutely dominated Rookie classes on the 900mm Praga at the local and national levels for several years before the 60cc micro classes and sanctioning bodies killed the class off.
I’m not a huge fan of the Arrow but I wouldn’t change off of it for wheelbase only if you are just getting started. Had a similar discussion in this thread with another Arrow parent with a very new driver:
I would say leave him in the Cadet as long as rules allow it and he can fit in it without hurting performance. The shorter wheelbase will help in cornering. I know when I got my Son in racing at 8, we wanted a Cadet chassis but rules didn’t allow it at our track.
Rules are beginning to open up here and many are getting in a Cadet to run Sportsman.
From what has been discussed above, it’s pretty clear that the exact time and age to move out of cadets isn’t super clear.
However, food for thought: Recently, I was at an event in Los Angeles, and one of the drivers under our tent was a pretty talented/quick racer. Usually, he was up towards the front of the pack. However, on this day, he was nearly bicycling the kart in every corner. I mean, it was bad. So we kept taking grip out, kept taking grip out, and eventually it was somewhat better, in combination with altering his driving. Worth noting that the kid was on the larger side for a cadet, and thus we concluded in addition to over-driving, his height and weight were causing the cadet kart to flex beyond the point where it could really roll through corners with proper performance.
So, the point I make is this: If you find yourself at some point encountering the kart being massively over-stuck, or struggle massively to cut enough weight off the kart/driver to keep near the min. weight requirements, that may be a sign that it’s time to move on from cadet.