Kid's first mtb sizing?

TimBay

Well-Known Member
My kid is turning 7 next month. I want to get him his first mtb. Have taken him to Allaire on his 20" wheeled SS bmx style bike. He's not a super confident rider and still isn't even confident riding standing up. He's about 4'1. Was thinking a geared 20" bike, but wondering if I should go 24? Pros? Cons?
 

stb222

Love Drunk
Jerk Squad
Get him the biggest bike that he can maneuver because kids grow really. That being said, a 24” bike maybe be too big. The frames still come in sizes so just wheel size isn’t going to be a good gauge.
 

TimBay

Well-Known Member
So my logic for either option is...

20" will likely be easier to ramp up skills with confidence. I kinda think since he's not a strong rider, this might help him get into it and progress faster.

24" won't have to buy a new bike for a few years. Better rollover for trails. Risk being too much bike, creating slower progression and frustration.

I'm leaning toward the 20" thinking he'll get a better season of progression and just bump him up next season. Might take him to a shop and just see how he looks/feels on a 24" though. IDK
 

stb222

Love Drunk
Jerk Squad
So my logic for either option is...

20" will likely be easier to ramp up skills with confidence. I kinda think since he's not a strong rider, this might help him get into it and progress faster.

24" won't have to buy a new bike for a few years. Better rollover for trails. Risk being too much bike, creating slower progression and frustration.

I'm leaning toward the 20" thinking he'll get a better season of progression and just bump him up next season. Might take him to a shop and just see how he looks/feels on a 24" though. IDK
See him on one will help make the decision. Try not to look at with it “dad goggles”. His skills will come in time regardless.
 

taylor185

Well-Known Member
Team MTBNJ Halter's
I'd say 24". my son is currently 4' 4" and has ridden a 24" for the last year. he has a little room to grow on it but the next size bike is not far away.

I think you'll outgrow the 20" in a heartbeat.
 

iman29

Well-Known Member
Based on my experience years back I would say the biggest factor is confidence. My oldest was on a BMX type Walmart bike fir his first times without training wheels and fell once and let the bike sit for a whole season. My middle son was younger but more determined got off training wheels much sooner before the older one and motivated older one to try again and ride.

I would say don’t predetermine what you will get based on size. If you can borrow or try both let him decide what he’s happy with even if he outgrows a smaller bike quicker. having the confidence to ride is not something you can spend money on later.
 

pkovo

Well-Known Member
My 2 cents... a 20" will fit best but as mentioned will be outgrown relatively quickly. 24" will likely be do-able but a touch big and may not help in the confidence area.

I have three girls ages 8, 11 and 13. They were all on a 20" at that age/size.

11 year old is still on a 24" at just over 4'8" and does really well on it. She'll need to be upgraded to something bigger soon though. 8 year old is big enough for a 24", at around 4'5" but still prefers riding the 20".

To STB's point above, wheel size doesn't always dictate the bike size though. The bike in my avatar was an older Trek MT60 which was 20" and really small and they could ride it early on when they were tiny. My 8 year old is on a newer version of the MT60 that is also 20" but it's a much bigger bike all around. I don't think they were sized, but the design sure changed.

A lot of the little mountain bikes are terribly heavy for their size. Two of my girls aren't super into biking, so they are fine with them stock and heavy, but for the one that really loves mountain biking, I stripped hers to the frame and used none of the original parts. In fact, she is telling me to stop working and take her to the Nassau Trails on it right now!
 

one piece crank

Well-Known Member
I’ll buck the trend and say get/build him a bike that fits and allows confidence. This can mean acquiring/building multiple bikes over several years, but it’s all about building a new cyclist. And what’s a few more bikes?

You don’t have to go for new, but you should consider weight. So getting a lightweight 20” racer and adding a fork later is super simple (and cheap).
 

UtahJoe

Team Workhorse
Team MTBNJ Halter's
My son is 7, not exactly sure how tall he is about 4' 1 or 2... I got him a kona process 24 and he fits good on it... just needed to take the dropper post off so I can put the seat low enough to get him started

He's like this big on it 😊
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Tim

aka sptimmy43
My son is 8 1/2 and has been on a 24” Specialized Riprock since his 7th birthday. He had pretty obviously outgrown the 20” by the time we got him on the 24”. I would say it was a touch big for him last year but he’s doing really well on it now. He’s tall for his age and is about 4’7” now.
 

TimBay

Well-Known Member
This is all great stuff. Gotta get him out to a shop (one with bikes) to see how it feels for him. Want to get new as it's a bday present. Figure if I go 20, I'll try to be somewhat less expensive but functional, but will drop more if we find a 24 that'll work for him since he'll be able to have it for a good long while. Thanks for all the experience and suggestions.
 

iman29

Well-Known Member
This is all great stuff. Gotta get him out to a shop (one with bikes) to see how it feels for him. Want to get new as it's a bday present. Figure if I go 20, I'll try to be somewhat less expensive but functional, but will drop more if we find a 24 that'll work for him since he'll be able to have it for a good long while. Thanks for all the experience and suggestions.
This is a great plan. Any riding with kids even better. Wish my 3 boys were more into it but I started them too late. He will always remember this bike bday. 👍🏻
 

Steve Vai

Endurance Guy: Tolerates most of us.
This is all great stuff. Gotta get him out to a shop (one with bikes) to see how it feels for him. Want to get new as it's a bday present. Figure if I go 20, I'll try to be somewhat less expensive but functional, but will drop more if we find a 24 that'll work for him since he'll be able to have it for a good long while. Thanks for all the experience and suggestions.

Kids bikes are in a huge surplus right now. Probably the only bikes that are.
 

TimBay

Well-Known Member
Thanks for all the advice. He's 100% a 24" rider. Popped into a local spot to size him up, with the bike shortage and fear of not having a bday gift and because he was stoked on it, we grabbed a cannondale trail 24. He had no problem getting used to the bigger tires. Took a quick ride at our local gravel path (Henry Hudson trail. Also got a first ride with my 3yo on the kids ride shotgun. She loved it.

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