07 January, 2019

A Polyvalent Made for Two

by Igor

Our recent New Year's Instagram post brought up several questions from readers regarding setup, fit, and handling using a stem-mounted kid's seat. We went back and forth about the pros and cons between a trailer and a seat for a long time. We finally decided on the seat for the ability to talk to him during the ride - which is an invaluable learning and bonding experience. After having gone on many, many short and long rides with him, I thought it would be a good time to talk bike setup and well as tips to keep both you and your kid happy.

A low trail front end design is a must. Kids are heavy and only get heavier. And while the weight isn't in the same position as a front basket full of groceries and a 6-pack, they still weigh quite a bit and you wouldn't want your wheel and handlebar flopping around. The handling of the Polyvalent is predictable and easy. It's such a fantastic ride, that it allows me to forget about the bike completely and really enjoy our shared flying-through-space experience (even if it's just down the multi-use path).

Upright, swoopy handlebars are your friend. Your arms need to clear the seat's sides and your chest needs to clear both the back of the seat and the kid's head + helmet, so the more upright you are, the better. I prefer the Curvy One Handlebars for their back sweep and width. An aluminum alloy stem would probably be ok (nothing specifically was stated in the instructions otherwise), but just to be safe, I paired those bars with our steel, 90mm Removable Faceplate Stem for an upright, visible, and safe position.

After the first spin around the block, I realized that my knees were touching the corners of the seat. I blame my long femurs. I'm probably not the first to find this out, but the solution is pretty simple. You can either go with a wider spindle (what I did), pedal extenders, or an MTB crankset. The important thing is that you need to get your Q-factor (tread) fairly wide.

Wide, cushy tires - I chose 650bx47mm WTB Horizons. They're not fancy, but they're not supposed to be. They are terrific work-horse tires. They're hearty, take lower pressure, and aren't terribly susceptible to punctures as very supple tires are. Please don't change your tube or re-fill your sealant with a toddler on the side of the road. Pro-tip: I use these tires tubed and add 3 oz of sealant to each tube. No worries about a blow-off and the puncture probability is down to nearly nil.

You won't be able to mount a front mounted basket or handlebar bag due to the leg extensions, so attach a saddle bag or pannier for snacks, change of clothes, diapers, and wipes - basically a mini baby bag. You're probably not going to be out long enough to necessitate a full sized bag, but bring the essentials just in case - you never know... Thank me later.

Of course, a positive attitude is a must! Sing silly songs, point out birds, go over some bumps, take breaks to look at horses, and go to the park. Have fun and happy riding!


Scott said...

Front-mounted is totally the way to go for a kid seat. My daughter and I started with an iBert and now use a Tyke Toter, and we've been all over our city, on bikepacking trips on my mountain bike, and even explored Yosemite Valley and never had to fight for a parking space. On the iBert I mounted water bottle cages under the legs for extra drinks, and when she was really little I was able to strap diapers and snacks to it too.

Oldcyclist58 said...


It want be long before you will need to graduate to a long tail bike. My grand kids love "Xtracycling" we have the hooptie, so both can ride at the same time. It beats the heck out of a trailer, and yes I have tried both!

Raul said...

On seeing the subject line, my heart jumped...I thought you had designed a tandem. :(

Anonymous said...

Where can I purchase that baby seat.

Eric Daume said...

Low trail is hardly a "must." I logged many happy miles on my Fargo with a front mounted kid's seat. What's really dicey is low trail while pulling a trail-a-bike. Not recommended.

Anthony said...

Thanks for this post! I have a similar setup using using an ibert, and my little guy loves it. I however have issues fitting behind the seat as the ibert projects pretty far back from the stem. It looks like that Yepp may be a bit further forward. Any chance you'd be willing to measure the distance from the stem to the back of the child seat on your setup? Thanks!

aubrey said...

I used the iBert pretty extensively, and thought it was great, especially when kiddo is very small. Way easier to talk, point out birds, as you say, and to notice when the head starts nodding when they fall asleep, inevitably. A swept back bar is necessary. I also found that a mixte makes it a lot easier to mount/dismount. A critical piece of the puzzle, as Anthony's noticed, is the distance from the back of the kid's seat to the nose of the saddle. I used a "nose-less" style saddle, an "ergo - the seat" specifically (dumb name, sorry), and it made a huge difference for me and my wife. When they get bigger, it just doesn't work, and the rear rack mounted seats don't either (chain stays are too short, and the kid is crammed into your back). The long-tail design works best (Bike Friday Haul-a-Day, Xtracycle Edge Runner, Madsen, Yuba, etc) and can def do 2 kids. It's awesome to take the kid(s) on the utility runs, but for fun, just get them on their own bike at that point. Balance bikes are the only way to go, then get them on a two wheel pedal bike when they're like 4! It's family fun time!

VeloOrange said...

It's a Thule Yepp Mini, any Thule dealer!

drew said...

Both my kids loved riding in a front mounted seat (we used the iBert) from the moment they were old enough to sit in it. My daughter graduated to her own two wheeler a month shy of her 4th birthday (and she never used training wheels!); I credit all the time logged riding with her mom and I for making her such a natural on a bicycle. I used the iBert mounted on an old Grant Petersen era Bridgestone RB-2, which I thought has more mid-trail geometry; but it rode just fine. even at speed. I just changed out the drop bar and downtube levers for a Milan bar and thumb shifters. My position took a little tweaking, but now that the kids are (sadly) too big for the front mounted seat, I have yet to return to a drop bar. My oldest (now 8) has been riding along side us for almost 5 years now, and the youngest (5) rides his own bike for short rides or a ride-behind trail-a-bike thing on longer jaunts. Indoctrinate them into the cycling life early.