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Seat type and butt pain and kids bike fit... (amateur question)


May 5, 2011
My daughter has a typical, big box store, US kids bike. We ride together as a family as far as 10 miles for lunches, parks, ice cream, etc... After about 5 mins. into the ride she starts complaining about the pain in her rear end. (the only butt whiner in our family) She needs a new bike anyway. We bought a Trek FX for my oldest (13yrs) which she loves. I was thinking to get a new bike for this middle girl too (11 yrs). But she likes her current bike and thinks she just needs a new seat. She wants a more padded seat. Bigger. Wider. My thinking is it's the padded, wider seat that causes all the butt pain because your butt cheeks rest on the seat causing all the muscles and tissue to hurt. If you had a more narrow seat that uses the sit bones for resting you'd have less butt pain. Isn't that correct? What I learned when I became a longer distance, road rider instead of sidewalk cruiser. Non bikers laugh at the skinny seats and wonder how anyone would be comfortable on them but isn't it the skinny design that is more comfortable for longer rides?

Also, my son does need a new bike and he's a very tall kid. He's in 4th grade. 10 years old but he's as tall as some 6th and 7th graders in his school and much, much taller than any Japanese kids his age. I need to get a good fit for him. Kids bikes in Japan are too small. He's a serious biker too. He wants to build his own bike for his new hobby. First he's going to take apart an old cruiser I have. Can anyone recommend an LBS with English service that will fit him with an appropriate bike. A kid. But a big kid. We used Y's road in Akasaka for previous fits and repairs and purchases but the English service isn't always the best. And the sizes are generally too small for kids bikes and too big for adult bikes.


Half-Fast Mike

Lanterne Rouge-et-vert
May 22, 2007
Non bikers laugh at the skinny seats and wonder how anyone would be comfortable on them but isn't it the skinny design that is more comfortable for longer rides?
My thoughts on racing bike seats: (1) they're built for speed, not necessarily for comfort, (2) the constant pressure on the pedals because you're trying to go fast lifts some of the weight off your butt, (3) they're designed to be used with padded shorts, (4) they are gender-specific.

I would suggest you take your daughter to a shop with a wide selection of saddles - perhaps Y's in Shinjuku 3-chome - and let her choose one that feels comfortable. Or order a Brookes B18 Lady and let her wear it in. Look after it and she'll never need another saddle.


Maximum Pace
Feb 5, 2012
Sage advice from Mike.

This is tough question and its like trying to fit a pair of jeans by looking at them on the rack; you need to try several different types of saddles in order to find the one that works for you.

It may also be a good idea to "youtube" how to measure sit-bones to ensure you get the correct width for a growing body.


Maximum Pace
Oct 25, 2011
My thinking is it's the padded, wider seat that causes all the butt pain because your butt cheeks rest on the seat causing all the muscles and tissue to hurt.

You're right. Soft seats may be comfortable on a short ride to the shop because they dampen shocks, but they don't properly support the sit bones and allow them to sink in, resulting in the weight spreading to softer tissue surrounding the sit bones, which means nerves and circulation get squeezed in places that aren't meant to be squeezed. That's why a firmer saddle is ultimately more comfortable for longer rides.

I also agree with Mike's comment though that cyclists who pedal harder move more weight off the bottom and onto the legs, which is one reason why beginners suffer more.

A Brooks saddle (I have the B17) is working really well for me, but you need to keep it out of the rain or it gets ruined very quickly.

As for English speaking shops, two members of the forums who are native English speakers work at Y's Road in Shinjuku and Shibuya. Otherwise I'd recommend going with a bilingual friend.


Maximum Pace
Hardest Crash
Jul 26, 2008
To try out extra padding, one option would be for her to try a padded seat cover. I have one that I use on the stationary bikes in my school gym, and it make all the difference in the world--from something I can't stand, to something I can easily spend 40 minutes on.

The one I have is gel, maybe 1500 yen or a little more.


Maximum Pace
Dec 14, 2006
The young growing lad will outgrow anything that fits now in about 12 months so putting together a bike piecemeal is an expensive proposition. I would just find a second hand bike that fits him and then let him spray paint it any color or style he likes. He can strip the bits off the bike, mask off any bits that dont need painting and then he can re assemble the same bits again. As far as sizing, measure his height and stand over, there are plenty of tools online to get you on the right sized bike.


Maximum Pace
Oct 11, 2009
What's the height / weight of your kids? And what kind of bikes (brand /pics /size) do they have now?

1) For the girl - maybe she just doesn't like to ride a bike (yet). Oftentimes kids will use the most obvious excuse to avoid the activity. My 6yo always used to say that the seat hurt her - when it really didn't, she just didn't want to ride. Now that she's around other older kids and they ride all over the place, her bike suddenly 'feels great' and she rides it all the time.

2) For the boy - I totally agree with Simon here. What do you mean by 'serious biker' ? Does he BMX at local park? Junior Track racing? CMX? MTB? Depending what he's into, there is a massive range of bikes (new and used) available.

FWWI soft, padded seats will almost always cause pain when ridden more than a few km. 2 things are in play here. If you ride more than a few km often, then your sit bones will become conditioned as well as the surrounding muscles and tissues so that a padded saddle offers LESS support than a firmer one, resulting in more pinching and vague positioning resulting in cramps and bruising. Heavily padded seats are more comfortable for people who seldom ride a bike or are placing most of their weight on the saddle and pushing lightly. Sprung, or gel type saddles may help overcome shock based trauma due to long rides - but they'll generally be quite firm as well to allow proper sit bone position. As a general rule, women have slightly wider sit bone position than men. But in my experience, such things as 'women saddles' are largely marketing hype and it really just depends on the individual more than anything.


Maximum Pace
Aug 28, 2012
Zoompast, your daughter is, ahem, of the female persuasion. People like that are, well, designed differently from people like me and perhaps you. Make sure that the saddle is for women. It should be concave in the centre. IFF a saddle for men is concave in the centre, then there may indeed not be much, or even any, difference between saddles for men and women. But my wife hated her 25-year-old "women's" saddle (short, wide, convex in the centre), and is perfectly happy with her current saddle (much narrower, marketed for women, and comfortable for me); and a friend hated her saddle till at my suggestion she went to Y's and replaced it with something for women.
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