Thursday, 15 September 2011

The 2-Child Brompton

We just got a second seat for our Brompton! This one is much larger and excellent quality with 5 point harness, reclining seat, and head rest with space for helmet.

I picked up the seat second hand, brand new, from someone who couldn't fit it onto his Dahon. It's tough with foldies, but a few modifications (mainly to the setback distance to the seatpost) and we were in business out riding in East Coast Park that very same evening!



This video is the very first time that Ethan and Talia rode on the Brompton at the same time. Listen for squeals of joy! It makes it all worthwhile...

All three of us loved the experience of being together. Ethan and Talia are quite attached to one another, so this new experience of being with one another and with Daddy is quite a thrill. Of course the speed makes it all the much better, though needless to say since I was carrying an additional 35kg load it was slower than usual.

More recently, I took both of them out on a more adventurous urban outing. We did some short distances on roads from Pinnacle to Lau Pa Sat for a satay dinner, then on to Marina Bay Sands for the evening light show. It was a great success, especially since I had tweaked the setup and the tire pressure so we were much faster. It's just amazing how well the Brompton handled this load. As someone once wrote, "A folding bike with small wheels like this shouldn't be able to carry loads this well!" But it does... As we were eating satay, Talia looked over at our folded Brompton with two child seats contorted around it and proudly said, "That's our bike Dad!"



Tech note: Total weight < 110kg, front bracket = 15kg, rear seat 20kg with mounting point < 5cm to seat clamp minimizing moment loading. I wouldn't ride the bike daily like this, but for the occasional outing it seems well within Brompton tolerances.

10 comments:

Derek said...

Don't mind me asking, what is the brand and the make of the rear child seat? Looking to get one too! Thank you.

Dennis said...

Looking for a workable seat for my brompton too. Where can I get one too? Thanks!

Luana Maciel said...

Hello!

I`m brazilian, and I wanna know what brand and model of this chair. I have a dahon and I`ve difficult to looking for it.

My e-mail is luana.l.maciel@gmail.com

Thanks

Nikolaos said...

Hi, i had the same idea with the rear chair but was not sure if the weight of my son and chair can effect any damages on the tube . The weight so far is around 20 KG ( 12 KG son) did you face any problems so far? Or would you rather recommend the front position? How did you assemble the front chair? Can you share any detail pictures? And what is the brand of the front chair? We just arrived in Singapore from Germany and have with us our BBs with us. For information thank you in advance. Email Ganitopoulos@gmx.de

Karmeleon said...

This is so interesting. What model is that Brompton and how much does that Brompton cost by the way? Easy to fold/unfold, put in/out car for a lady rider?

Do you keep the back childseat on all the time or you fix it on only when you need ot use? I'm exploring such ... only kid I have to do pillion is my 3yo (about same age as your girl), but I doubt I'd put him in front. He's done quite a number of long rides with me on back childseats on rental bikes.

Ivan said...

Hi Everyone. These are all custom modifications so I cannot recommend them to others for safety reasons (you have to be able to understand the mechanics, check regularly, and judge safety for yourself).

The front seat is a cheap SGD$35 seat from many shops. Originally it is designed to clamp to a rear rack. I mounted it to the C Bag frame with the included bolts and reversing the bottom plate. Additional hardware was very simple and inexpensive. The very cool metal bar my daughter holds onto however is not part of the cheap seat. That's an old Profile Aerobar that I attached for her. It is necessary to put something on for your child. This was done using no heavy tools. If you have trouble figuring it out then you probably shouldn't do it for your kids cos it may not be safe. I would not go over the stated 15kg child weight due to front block limit.

The rear seat is the same as many on the market. Be sure that the clamp can fit on the 33.9mm seatpost. You may also have problems with your feet hitting the child's feet. I modified my seat by moving it further back (check the design of your seat to see if you can do this). The trade off is that with the child on the bike there is so much weight on the rear that it can tip backward if you're not careful. Thus you need to be highly confident with your bike.

I usually ride with BOTH children on front and back. The weight distribution that way is very good and stable. If you are a skilled rider you will have no problems with control. I have it setup so I can use my clipless pedals so maintain my same cycling position for longer rides with them.

I now have another option with a trailgator pulling my son on his bike behind my Brompton. You can see the newer blog post.

Philip's Investment Diary said...

Hi Ivan,

Thanks for sharing these great tips!

I'm planning to get a Hamax child seat (similar to the one you have) to mount on my Brompton as well.

I see that you have mounted the bracket on your seat post. Isn't it very cumbersome to keep mounting and dismounting the bracket from the seat post in order to fix up the child seat?

Ivan Liew said...

I have since changed Bromptons to an S2L but still use both child seats. The rear seat is attached to a Brompton steel post which I have cut off the flared end to quickly remove. I have a second Ti seatpost (no flared end) with its own saddle, so I change setups in <1 min.

Timothy D. Birt said...

i can still see to the bottom of my front wheel and due to the compact design.. it does not obstruct the legs movement as well.. the seat is easily removable as well.. overall.. i am very satisfied and happy with it.. it can be mounted on a variety of bicycles but it just doesnt state if it can be mounted on a foldie.. but i see that with the right foldie, it should not be a problem at all.."

Jamie R. Iorio said...

centralised and doesnt change the handling of the bicycle.. even rider mount and dismount is easy.. the WeeRide Kangaroo is rated for kids weighing up to 40lbs (18kgs)..mostly due to the massive support system .. the resting platform works both as a support for the kid to grab on to and rest their weight on it when cycling and oso as a comfortable headrest when they doze off during a ride.. so far it has not obstructed my view ahead..