I live in Japan. My wife has a regular good bicycle with a basket. I have a son who is 1 year and 8 months (he is 11 kilograms and is currently carried in a baby sling). My parents who live in Australia want me to buy a bicycle with a manufacturer installed child seat. I want to know if they're right that a baby seat installed after manufacture by a bicycle shop (I don't think we'd have the tools to it ourselves nor is it sensible) is not as good as manufacturer installed seat? Of course there are a lot of factors that could affect the installation but roughly speaking is there answer.

Here is the exact bicycle that my wife has: https://www.aeonbike.jp/products/2162

Aeon BSO

Here is an example bicycle with baby seat: https://www.aeonbike.jp/products/2152

Aeon BSO with rear seat

  • 1
    Seats installed when the bike is built are incredibly rare in Europe. Can you link to some examples? You should probably also indicate what you're thinking of having fitted (front/rear, rack/seatpost). I use a seatpost-mounted seat which I fitted myself and am happy with the stability, security of mounting, and the effect on the handling. It doesn't move laterally though is designed to have a bit of give in the vertical dimension. Riding with some weight up high takes some getting used to but is fine if you start before your little one gets too big.
    – Chris H
    Jun 12, 2017 at 9:47
  • 1
    Manufacturers do not attach child seats to bikes, but a bike shop certainly would. If an LBS can't fit a child seat properly, they're not much good! Personally I like the forward-facing top-bar mounted seats like the WeeRide, mostly because they're centered. The only bikes I can think of that are built with child seats would be tandems and some cargo bikes where there are seats and belts in the cargo tray - they're not cheap though. Finally, you can listen to the parents input, but make your own decision as adults and parents yourselves.
    – Criggie
    Jun 12, 2017 at 10:23
  • @compton Excellent spotting - you made me read it again.
    – Criggie
    Jun 12, 2017 at 10:23
  • 2
    My lack of Japanese prevents me being sure, but the model with the integrated seat looks intersting, in that the smaller wheels lower the centre of gravity of the child (who can be assumed to wriggle). This shoudl imrpove the handling. But a good sturdy step-through (which is what she appears to already have) with a child seat added to it, is probably the most common way to carry children on a bike, at least here in the UK. To put it bluntly, grandparents fuss, usually about the wrong things -- do they ride themselves?
    – Chris H
    Jun 12, 2017 at 15:05
  • 1
    The discussion should be about the bike design, not who fits the seat. The question the OP should have asked is "Is a Cargo bike better than a traditional bike for carrying children".
    – mattnz
    Jun 12, 2017 at 23:03

3 Answers 3


TL;DR I feel trailers are a safer option for small children, but the circumstances of your commute may mean that a trailer is not an option or is a huge inconvenience. In that case, I believe that a mechanic installed child seat is/can be just as safe as a "factory" installed child seat and likely far less expensive than a new bike.

I (personally) don't ever recommend that type of child seat. Even expert cyclists can crash and since children are often not good at crashing (they don't have instincts to roll, etc) those seats worry me. Accidents happen and those style of seats have never felt safe enough for a small child (let alone an infant). Both of my children (now three and four) have been towed hundreds of miles in a trailer, which essentially encloses them in a roll cage. I've had times I've slid off trails into snow banks, and a rear seat would forced a child's head under snow. With a trailer, it simply tipped into the bank and had no ill effects.

All that being said, I don't think their is really a difference between the factory installed model and a well built child seat installed by a good mechanic on a bike properly setup for a rear rack. In your case, if you were looking at the money to purchase and entire new bike, I may consider simply purchasing a trailer which would work with many different bikes and possibly be of other use to you as well (some are convertible and can be used for non-cycling activities as well). If money was an issue, I personally wouldn't differentiate between a factory installed model and a mechanic installed model.

Double........or single

  • 1
    +1 for a good alternative even though I disagree with your conclusion. I have both. The trailer takes up too much road to be safe given potholes and cars overtaking (I flat out won't use it in rush hour). Also trailers are forced off some of the bike paths round here by the width restrictions desinged to stop motorbikes -- so more road time, and on bits of road that are worth bypassing on bike paths). A child should be strapped in to the seat -- rolling isn't an issue; my worry was always that my daughter would reach out to try to break her fall and that of the entire bike.
    – Chris H
    Jun 12, 2017 at 15:42
  • 1
    @ChrisH My kid rides are all protected bike path, neighborhood or trail. I don't trust people in cars around my kids unless they are in a car as well, so that part I agree with. The single trailer isn't much wider than my handlebars. And I completely agree with tipping, small fingers gripped onto the seat edge coming down on pavement with my weight, bike weight and child weight was always too scary a proposition for me. With the roll cage, they can't get their little bits out to get mashed. Jun 12, 2017 at 15:51
  • My bars are higher than the width restrictions and I can see them. Neither of those applies to the trailer. We also have chicane-type restrictions to slow bikes down. With a trailer they would mean stopping and walking, lifting the bike round the corner and possibly even uncoupling the trailer.
    – Chris H
    Jun 12, 2017 at 15:59
  • 1
    @ChrisH That sounds like the standard urban compromise. Make cycling moar safe using techniques that make it more difficult to cycle, but impossible to drive. I am completely unfamiliar with Japan, but I'd guess much of your experience is more applicable than mine. Jun 12, 2017 at 17:01
  • I've been to Japan on business, but before I saw traffic with a cyclist's eye (I wobbled around bike paths a bit on a BSO in those days). But lots of lanes of dense traffic on the big roads plus some tiny roads in Tokyo and Sendai wouldn't suit me with a trailer. But it depends what's commonplace there.
    – Chris H
    Jun 12, 2017 at 19:36

As you know, "Mom Bikes" (mamachari, ママチャリ) are huge in Japan. It's not unusual to find some with three sets of child seats (in front of handlebars, behind handlebars, and behind seat). Many contemporary mamachari now are electric assist, which is great. Note that even when a dad rides a mom bike, it's still called a mom bike.

Mamachari Google Image Search

A quick sidenote: child trailers which are very common in the USA and front-cargo bikes such as are common in Denmark, are not common in urban parts of Japan. They are simply too long to park in most supermarket and train station bike stands. The only trailers I've seen in Japan are ridden by foreigners. The only front-cargo bikes are for delivery companies. You should check where you expect to park the bike to see if there's space. This is less of an issue if you're in the boonies.

About buying and attaching child seats to mom bikes:

Rear Seat: The child-seat that sits behind the main seat is a standard design that is designed to be easily attached (and then detached when the kid gets larger). You can get these types of seats on the after market and they'll be just as good as getting them pre-installed on a new bike, assuming your old bike has the proper rear-rack installed. Your bike shop will tell you when installing the seat about compatibility.

In your specific case, however, the bike with the rear seat pre-installed has smaller tires and an elongated wheelbase which aids in comfort and safety (the child is lower to the ground and there is more space between the child and the rider).

Mid Seat: The child-seats that are either immediately behind the handlebars can be found in the aftermarket. But as the bottom left image in the google-image-search above, you can see that some seat designs will cause knee-strike. Generally these should be avoided unless it's for a very small child or your bike is on the larger side and there's no risk of knee strike.

Front Seat: The bike seats that are placed in front of or on top of the handlebars are usually custom to that bicycle as they depend on the shape of the handlebars or front wheel.

Note also that mom bikes are very cheap on the used market (once kid goes to school and mom goes back to work, the bike gets retired). So it may be cheaper to sell your bike and get a mom bike with a rack installed.

tl;dr: You can get a rear seat fairly easily and it should just plug-and-play on any standard mom bike that has a rear rack. Try to avoid trailers and cargobikes unless you know you can park them where you need to go. Explore used options. However, with the two bikes you've shown, the actual bike base is different (26" vs. 20" wheels, elongated wheelbase) so you might find the bike with the rack preinstalled more comfortable and safer for child and parent.

  • This almost completely supersedes my answer with the benefit of experience too. +1 and maybe I should turn my answer into a couple of comments. The only thing I'd add (and this may not be relevant in Japan) is that seatpost-mounted child seats are a good option if you don't have suitable rack-mounting points, if you still want to use the rack for small things, and in some other cases.
    – Chris H
    Jun 13, 2017 at 8:02

Bike seats designed for retrofitting and carefully chosen are going to be as good as anything fitted in the factory to a fairly normal frame. They will be mounted in a very similar way, and may even be the same seat.

By all means take advice from a bike shop on which models are suitable for your bike, and get them to do the fitting, I didn't feel the need to personally.

Having ridden with a rear seat since my daughter started nursery and with a trailer more recently, I'm strongly in favour of the seat unless there's a wide dedicated bike path with a decent surface. Given my proportions and those of my bikes a top-tube-mounted seat was out of the question, but they look like a very good idea.

  • +1 And God said unto the cyclists, "THOU SHALT KNOW THY COMMUTE." Jun 12, 2017 at 16:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.