Fugo’s Tomii Cycles Disc Dirt Machine

As a parent of a child who has taken up cycling, the last thing on your mind should be buying a custom bicycle for them. That is, unless the bike can literally grow as they do.

Nao at Tomii Cycles felt challenged by this very issue. Rather than fillet braze a new frame every year as his son Fugo grows, he developed a bicycle frame that could adapt to the rapid growth of a young boy.

This frame utilizes Paragon slider dropouts and disc brakes, two crucial components to the equation. In doing so, this frame can accept 20″, 24″ and 26″ wheels. All Nao has to do is relace the hubs as Fugo grows. From there, a longer stem and an extended seat post will take care of other fit concerns.

At this weekend’s cross races, I caught up with Fugo after his race and asked him if I could shoot photos of his beloved race bike. When I asked him what his favorite part about his bike was, he replied “the gears” – a fact that Nao brought to my attention later – “he just figured out how to use the grip shifters.”

Ride on, Fugo, ride on!

  • Patrick Murphy

    Nice! One of my favorite builders. Nao’s Flickr is an excellent follow. He incorporates photos of family adventures and home life into the mix of beautiful frame build process shots.

  • mywynne

    Forwarded this to the fiancee: “Ok, fine, I guess we can have kids someday (but only if they’ll be this rad)”

  • Greg Ralich

    Miss this guy more and more every day! Thanks for sharing these awesome shots – he is the best kid!

  • boomforeal

    interesting idea! as someone who’s spent way too much time thinking about kids bikes, a few things stand out: 1) the front end looks way high with 20″ wheels. it will probably be perfect when he moves up to 24″s and sticking with the same fork will mean the bike retains the same geometry, but that’s a downside; 2) the accommodating different wheel sizes with sliders idea technically works, but even with the sliders the chainstay lengths are going to vary drammatically with different wheel sizes. with 20″s they look (and i imagine ride) ridiculously long; 3) cranks are another part that will have to be swapped out as fugo grows. those sinz cranks are perfect for little legs. they also make such a high bb unnecessary…

    cool concept, but i wonder how much performance fugo is forgoing to have a bike that (mostly) works at different growth stages. kids bikes have traditionally sucked but they are getting better. getting the right bike at each stage and flipping it to a younger rider as yours grows might be a better idea

    • Luke

      20″ BMX handlebars usually have between 150mm and 200mm of rise. That 25mm MTB riser ends up in about the same spot.

      20″ BMX’s commonly have chainstays between 350mm (or about 13 and 3/4 American thumbs) and 375mm. This one’s on the longer side — like most BMX race bikes — when slammed forward. Slammed rearwards it’s at 395mm which is about the length of the stays on a 26″ dirt jump bike, and about the shortest you can get with 26″ wheels. So yeah, that 20mm of sliding room is important and allows 3 different wheels sizes to be used.

      Swapping a crankset = 10 minutes and about $80. Big deal.

      Granted the bb height isn’t going to be perfect with all wheel size/ crank length combo’s but it won’t be terrible.

      I’ve never met a kid who was concerned about how much performance he was forgoing on a bike. I guess they leave that to people who spend too much time on bike forums.

      Killer bike Nao. A lot of thought has obviously gone into it. Congrats.

    • Andy Moore

      The kid does look very seriously bothered by his bike’s performance compromises. NOT!

  • Harry

    Japanese people tend to be really good at life.

  • Ely Rodriguez

    That bike is rad, great job Nao! Indeed, swapping bikes every couple of years takes some thought and effort. We need more modular kids bikes.

  • Tomii Cycles

    Hey John! Thanks for the awesome pictures. Here is my idea for this bike.

    Concept ) I don’t want to build bike every 2 (or less) years. Kids grow fast. With this bike I don’t have to build at least 8 years. (I hope!)

    Fork ) The fork length is similar to 24″ suspension fork (Just in case he want to suspension fork in the future) Also this is not too long for the 20″ bikes. Most 20″ kids bike has high handlebar position like BMX. and this is MTB.

    Chainstay ) Current chainstay length is 375mm (this is the common length for the 20″ bikes. Actually, I have to have at least 370mm to work RD correctly) The max chainstay length is 395mm with paragon slider.

    BB drop ) is 10mm. This is the common drop for the kids bike. Most 20 and 24″ bike has drop between 0 – 15mm. Again, this is MTB.

    Angle ) HT 69* and ST 73* angle is the pretty good for 20 and 24″.

    This bike also fits 26 x 1.25

    This bike needs many new parts when kids get bigger. (Wheels, cranks, stem and handlebar) I think that is the FUN part of this bike. Kids can enjoy the bike, also bike geek Daddy and Mommy can enjoy customizing parts! New parts = Awesome!

    • mywynne

      So, so, SO awesome! So much love put into it, too.

    • Greg Ralich

      And then… only after he’s beaten it up and worn it out – Aila gets it!!!

  • Western Rapid

    What a great post for Christmas! Awesome work!

  • dontcoast

    dat saddle too!!! :) :) :)

  • kermitonwheels

    Kids and bikes is sooo much fun. Wonderful concept!

  • Matt

    What chain guide is on there? I have the same Sinz cranks on my son’s bike and need a decent guide.

    • boomforeal

      Looks like a Paul chainkeeper? I’ve got them on my cx bike and my son’s mtb – they work great!