Pink Children’s BicycleSee all questions about commodity
Hello, my name is Gabrielle and I’m your commodity consultant for today. I can affirm from my own experience that riding a child’s bike certainly isn’t easy! I’ve been doing some research and have found the following…
Whilst there isn’t a hard and fast rule for fitting a bike to size, there’s some guidelines which suggest that it’s not wise to ride a child’s bike (even though it might be easier to mount). Firstly, adult bikes are measured by their frame-size, whereas children’s bikes are sold on their wheel size (have a look on here for specific measurements http://www.whycycle.co.uk/buying-a-bike/bike-sizing-advice/). This means that the frame on a child’s bike does not match adult height guidelines- if you’re standing, you should be able to put your foot on the floor pedal and your leg should be flat. If the bike frame is not measured by height and is focused on wheel size like a child’s bike, you’re not likely to be able to do this.
It’s quite interesting, because it turns out that bikes used to be measured from the bottom bracket to the top tube centre line, today it’s determined by the measurement of the seat tube because that’s what determines how the rider actually sits on the bike (see http://www.sheldonbrown.com/frame-sizing.html for a picture to explain this).
Measuring and having the correct frame, rather than a bike that’s too small (like a child’s bike) is particularly important because your weight should mostly be held using your strong thigh muscles pushing onto the pedals. If you can’t put your leg flat when your foot’s on the bottom pedal, you end up leaning forward too much, putting the weight on your spine and arms which do not have the same muscular strength. This ‘Bike Forum’ discussion suggests that you particularly end up putting too much stress on your hands, leading to blisters, pain and even carpel tunnel syndrome in some extreme and prolonged cases (http://www.bikeforums.net/general-cycling-discussion/611894-ramifications-riding-bike-too-small.html). But leaning forward too much due to a poorly fitting bike seat also means, potentially more seriously, that you’re excessively bending your torso and hunching over. If you imagine your spine, it’s made up of disks of spongy tissue between the vertebrae. These disks rely on good blood supply which circulates best when you’re moving. If you’re sitting too far forward or bending, your spine has to hold up more weight, putting pressure on the disks (risking rupture) and also depriving them of nutrients (according to Dr Hisey at http://www.webmd.com/back-pain/features/how-to-wreck-your-back?page=2 ).
There’s a really good experiment that you can do at home to show this back pressure which I used to do at work when we had manual handling training. Blow up a balloon to about the size of a cricket ball and have two cans of fizzy drink. Get one can (with the ring side on the table) and place the balloon on top into the indented side. Do the same with the other (the indented side again against the balloon and the ring side facing up). If you push the cans together, you’ll see the balloon disperse evenly around and it’s incredibly hard to pop. But if you put one can at a 45 degree angle, you’ll see the balloon excessively push out of one side and find it much easier to pop. The cans act as your vertebrae and the balloon the disk of spongy tissue inside it. When the cans are in the ‘straight-up’ position, is when you’re sitting properly putting little strain on your back, but when the cans are at an angle and the balloon is herniating is when you’re sitting too far forward or hunched over, like riding a poorly sitting child’s bike! This hunching over also reduces your lung capacity by up to 30%- which if you’re on a long cycle can have a potentially huge impact (http://www.breathing.com/articles/posture.htm).
If your seat is too low you’re also risking knee damage as your knees are forced outwards and have to take the pressure and weight of riding on the joint itself rather than allowing the strong leg muscles to help (http://www.trishop.com/five-signs-your-bike-doesnt-fit).
So, in short, whilst you can ride a child’s bike, it’s not likely to be the wisest idea, both in terms of comfort, back strain and knee problems! There’s also some evidence that children’s bikes are heavier and harder to manoeuvre on serious cycles.
If you wanted some more information on the perfect bike sizes, this video is great…https://www.youtube.com/watch?v=9XWsz5-VYFU. This website also has some great measurements and picture measurements http://guides.wiggle.co.uk/wiggle-bike-size-guide.
Thanks so much for your question- it’s definitely taught me lots about bikes!