Kids bike sizing

[Osmosis]

Hi everyone,

I've got a nearly 10 year old that is currently on a Norco Fluid FS 24 (24" wheel) that he looks to be outgrowing at 143cm tall. I've put a 60mm stem on it to buy a bit more time, but ultimately I'm looking for the next size up. Like everyone, I want to maximise the life of the next bike, but still want something that fits and is fun to ride.

I'm currently looking at a Norco Sight A3 27.5, which seems the best bang for buck (would love the A2, but it's more than $1000 more). The problem is I'm torn between sizing. According to Norco, he should be on a Sight Jr, but that's barely bigger than his current bike and I can see him outgrowing it again inside 2 years. I haven't been able to test ride a Sight Jr, but I have tried him on a Sight A3 Medium and he seemed to cope with it okay (just a parking lot test ride).

The Reach on his current 24" is 350mm. The Sight Youth is 395mm and the Sight Medium is 455. So effective 10cm longer for the Sight Medium. The standover difference between the Sight Youth and the Sight Medium is only 2.3cm and he can already safely clear the top tube on the Sight Medium

All the Sights have extremely low top tubes (compared to other bikes) and he can stand over the top tube of the Medium with both feet flat on the ground, so no real risk of injury. So I guess my question is, if all other things are equal, i.e standover is fine and seat to pedal is fine, what is the downside in having a bike that is too long for someone to grow into, aside from maybe being a little bit hard to manual for the first year?

Basically I'm looking for someone to tell me that I'm not a bad father for going straight to the Sight Medium, but any insight on sizing and the downsides of doing this would be helpful!

 

[rockmoose]

My lad is still on his xs sight at 13. He is rapidly approaching my height (173cm), but maybe close to 160??

I thought he would have outgrown it by now, but no. He will transition straight to a medium after. Has been on the xs since he was 11.

 

[davee]

I also have this issue but my son barely rides.
If you are torn could look at the size small might fit him better now can always the upgrade bits and move to just a frame when they no longer fit

 

[Dales Cannon]

I think there is more potential harm riding a frame that is too big as opposed to keeping him on a smaller frame a bit longer. That increase in reach is significant.

 

[yuley95]

I think there is more potential harm riding a frame that is too big as opposed to keeping him on a smaller frame a bit longer. That increase in reach is significant.

I agree with this. I know it's a significant cost to be changing good quality bikes every 2-3 years but one of my kids lost a fair bit of confidence an d interest in riding when we got a bike that was too big for her so she could grow into it. Maybe she would have lost interest anyway but I think being on a bike that felt too big and a little out of control contributed.

 

[Osmosis]

My lad is still on his xs sight at 13. He is rapidly approaching my height (173cm), but maybe close to 160??

I thought he would have outgrown it by now, but no. He will transition straight to a medium after. Has been on the xs since he was 11.

I'm kind of jealous of your height I'm 188cm and ride an XL Spectral and I guess part of my concern is that if my son jumps up frame sizes every 2 years, I'm going to be looking at buying at least four more bikes (or possibly 2 if I can put him to work at age 14). I could probably handle that prospect, but given an entry level aluminium bike now costs around $4,500, I'm looking at $18,000 in bikes for the next ten years. I just can't afford that.

It wouldn't be so bad if there were half decent cheap second hand bikes around, but I've been stalking Gumtree and FB marketplace and most bikes seem to have maybe a $500 discount off their retail price. The other option is to go the hardtail route, but this is a kid who loves trips to Thredbo and riding some of the gnarlier tracks at Stromlo, so a hardtail isn't an option.

It's pretty much the combination of the above factors that's got me thinking of skipping sizes.

 

[Osmosis]

I also have this issue but my son barely rides.
If you are torn could look at the size small might fit him better now can always the upgrade bits and move to just a frame when they no longer fit

This is actually a good suggestion, but Son No. 2 is three years younger and is lining up for hand me downs, so frame upgrade with same components route isn't viable until we get to bigger sizes.

 

[Dales Cannon]

I sort of did the hand me down thing. Both were riding 24" bikes then #1 went to a small Giant hardtail frame I picked up as nos and grabbed a used Diamondback in med for the bits. Then when #2 went up a size I had tracked down a GT idrive with some sad gear and put the best of what we had on that, picked up the missing bits and put together the Giant again. Went to a Norco fluid 2 frame for #2 then did the upgrades from there. Occasionally generously donating bits from my bikes as I replaced those (with betterer parts). It did work out cheaper for us and the 24s and the other frames went on to nephews and friends.

 

[Cardy George]

My 2c is it absolutely depends how confident a rider he is. Ex-VC started racing at 10yo on a 24" because that's what he was riding at the time. When he decided to stick with it we put him on an adult sizing small frame 27.5. He said it did feel weird at first but it was only a matter of weeks before he had adjusted. 3 years on and that bike is just on the small side, but still good enough to ride to school. He's 13yo now and tomorrow I put together his Medium/Large race bike.

The Little Sender however is a different story. He's 10.5yo now and raced a 20" until last December when we put him straight onto an adult small 27.5. It was like a duck to water. Before we bought it we put him on his brothers bike and he looked like he'd been on that size forever. Some people just become one with their bike and he's one of those people. We had a 24" in the shed and if he'd shown any hesitation with the big bike he would've been put on the 24".