WOOM4 seal - updated

**The current WOOM4 weighs 17.5 lb.**

Buying your child’s first 20″ bike is akin to buying them their first car.  Somewhere between reading about shifters, geometry and gear-ratios you think, how did they get this old?  With gentle rides in the park gone for good, speed, power, and performance are now top on your list. The best 20″ bike really depends on where and how your child rides (street, mountain, city or BMX), but we found WOOM’s lightweight, quick and nimble 20″ to the best all-around bike we’ve tested.  With a lower-center of gravity, bottom bracket and handlebar height, the WOOM4 is well equipped to comfortable take your child from sidewalks to basic trails.


Built with lightweight AA-6061 aluminum, WOOW’s frames are lightweights and rigid.  Backed by a solid 5 year, hassle-free warranty, every frame is built to last.  Made of ChroMoly steel, the fork is responsive and offers some dampening.  But wait, it doesn’t have a shock!? While shocks can be extremely helpful for kids hitting the single-track or the pump track, for the majority of kids, it is more advantageous to skip the shock to help save on weight.  In addition, most shocks on kids bikes are pretty worthless and act as merely eye candy. For those high-adventure kids looking for a front suspension bike, many big names bike brands have released light-weight 20″ with front suspension.


The optimal geometry of a 20″ kids bikes is also quite different than on a 16″, 14″ or 12″ bike. Kids tall enough to advance to a 20″ have generally already mastered balancing, stopping and starting a bike and are ready to progress to a more aggressive, lower center-of gravity, body position.  In addition, on a properly sized bike, they shouldn’t be able to put both of their heels on the ground, as they will likely out-grow the bike too soon. Instead, as long as they can touch the ground with one foot while seated on the saddle, the bike is a good fit.  As a result, kids can properly fit on a bike with a minimum seat height 2″ to 2.5″ greater than their inseam.

In addition to the body position of the rider, the position of the child on the frame makes a great impact on the handling and performance of the bike.  By lowering their bottom bracket, handlebars and shortening the crank arms (the bars that attach the pedal to the frame), a child is able to sit lower on a WOOM bike, thereby decreases the overall center-of-gravity of the rider.  When compared to the standard bottom bracket height found on the mid-range Novara Pixie, the difference is significant.

WOOM4 vs. Novara

Crank Arms

A lower bottom bracket also requires a shorter crank arm (to keep the pedals from hitting the ground when turning the bike), which has additionally benefits to the rider.  A shorter crank arm for kids (for adults there is certainly more science to this), provides a lower up-stroke height (shown below), which allow for a more efficient knee bend angle.  In other words, the less cramped a child’s legs are when riding, the easier and more efficient their pedaling will be.  Even when their saddles are set to the same height, the Novara requires a much tighter knee bend than the WOOM4, making the Novara more difficult to pedal.

WOOM4 angles

WOOM4 crank length


In addition to knee bend angles, the amount of splay a bike requires of a child’s legs is significant.  The greater the splay, the less efficient and more uncomfortable a bike will be to ride.  In order to save money, most kid’s bikes use components designed for the wider hips on an adult. When riding these bikes, kids have to splay their legs to pedal to compensate for their naturally narrower hips.  To provide for a more comfortable ride, WOOM uses components specifically designed for kids bikes, which allows for a narrower Q-factor.  By looking over the top of a bike, the Q-factor, or the distance between the pedals, can be seen.

WOOM4 q factor


The newly updated version of the WOOM4 comes with grip shifters versus trigger shifters.  Trigger shifters are slightly easier for kids to activate, but for most kids, their fingers aren’t long enough to reach the triggers.  Grip shifters take more effort to activate, but are generally easier for kids to use.  The twisting motion can be challenging for kids as they can twist too hard, causing them to tweak their handlebars and crash.  In the end, there isn’t a perfect shifting solution currently on the market for kids, both trigger and grip have their drawbacks.

Gearing (Performance)

Aggressive riders will also enjoy the higher gear-ratio on the WOOM4.  With a larger front cassette, the WOOM4 allowed kids to easily power up and down mild elevation changes.

WOOM4 off road

WOOM4 vs. Isalbikes BEINN 20″ Small

Islabikes and WOOM both make amazing bikes, which utilize the proven long and low geometry (long wheelbase, lower bottom bracket), but which is best? While their bikes are similar, there are several significant differences, which lead our testers to prefer one over the other depending on their skill level and riding conditions.  In general, higher gear-ratio and trigger shifters of the WOOM4 were much preferred by more experienced or aggressive riders, especially on non-paved trails.  The lower gear-ratio and narrower tires were preferred by more timid riders as well as those who ride on mainly paved surfaces, especially for longer distances.

WOOM4 vs. IslaIsla vs. WOOM 2

Additional differences include crank size and rims.  The WOOM4 has slightly longer cranks than the BEINN small with 120mm vs. 114mm.  The BEINN 20″ large, however, has 127mm cranks.  Both bikes also have lightweight rims, but the Islabikes saves a slight amount of weight with 20 spokes, versus WOOM’s 34 (performance is the same). Islabikes rims, however, only take Presta valves, which are MUCH harder to find replacement tubes for than the Schrader valves on the WOOM.  We have yet to find a 20″ or 24″ Presta locally, so ordering backups ahead of time online is essential.

Isla vs. WOOM 20


Lastly, the Islabikes is a pound lighter than the WOOM.  For more riders, the difference in weight was a non-issue.  In fact, when one of 8-year-old testers, who typically rides a big-box store bike, had the chance to ride the WOOM4, he promptly got off of it, held it up above his head and yelled, “THIS BIKE IS SO LIGHT!”.  Like the other features previously mentioned, those testers who often road longer distances on paved surfaces, did prefer the lighter-weight Islabikes.

Isla vs. WOOM 4

Bottom Line

The WOOM4 is the best all-around 20″ bike we have tested.  Rugged and nimble enough for moderate single-track riding, yet comfortable enough for street riding, the WOOM4 is the perfect bike to take your all-terrain rider.

Where to Purchase

The WOOM4 is available at www.us.woombikes.com for $449 (with free shipping) as well as on Amazon.


      • SR_LGR

        Thoughts on sizing would be helpful…. my son is turning 6, he is 45 inches tall. He’s currently riding an
        Islabikes CNOC 16, which is a really nice little bike. Our “dilemma”
        is that he’s a very strong rider and spends most of the time fully
        maxed out with the single-speed gear ratio. It’s actually unsafe, because he starts spinning his feet so fast that they regularly fly off the pedals and create sketchy near-wipeouts. He’s ready for gears,
        and probably for the extra glide of larger wheels. Is he still
        too small for a Woom 4? I know he could ride the Beinn small, but I don’t want him to have the same issue of maxing out the smaller front cassette.

        • I agree, gears are in order. If he is a more aggressive rider, then the WOOM4 would be a good choice as it has a larger gear-ratio, but I think he would do just fine on a WOOM as well. My tall 6yo just graduated from his Islabikes BEINN 20″ Small to his WOOM5 Supra and loved both of them. In addition to gears, I would also consider the differences in shifters between them. The WOOM’s have trigger shifters while the Islabikes grip shifters. While learning gears, the grip shifters were easier as kids only have to worry about twisting one thing front and back, vs. trying to figure out which button to push. Having learned on grip, my son now does great on his WOOM. So which is best. In the end, I don’t think you could go wrong with either, but is he is really aggressive or riding on non-paved trails, then I would go with the WOOM, if not then I would go with the Islabikes.

          • SR_LGR

            Thanks Natalie. How tall is your 6yo?

            • Opps, that would have been helpful. He is 50.5″ with a 22″ inseam.

              • SR_LGR

                Wow — big boy!

              • SR_LGR

                Never followed up on this… we held off on getting a new bike until Christmas, and a growth spurt in the interim make this a non-issue. We got the Woom4 and he has be RIPPING on it. What an amazing bike. I never thought I’d be doing for 1.5hr rides on twisty singletrack with a kid this young. What a blast. Woom4 is a great transition for a kid coming off an Islabikes CNOC.

              • Awesome! WOOM’s are pretty amazing bike and the WOOM4 is a great starter bike for mountain biking. I’ve seen a lot of 20″ bikes that are just too aggressive for kids. Sure when riding single track, you want them to be leaned forward more, but too much and we’ve found that kids tire out quicker and are often not as confident on overly aggressive bikes. Thanks for reporting back!

      • davidreichel

        Great site. Curious if there is enough space in the Islabike to fit a 1.75 tire and if there is space in the Woom to fit anything larger than a 1.75? Also, just noticed that it appears you weighed the Isla with its kickstand. No big deal, but obviously removing that (which many folks would do) would obviously drop it’s already light weight even more.

        • Good call on the kickstand, I should really get those weights updated. As for the tires, the Islabikes should be good to go with a 1.75, but not any bigger. The WOOM has enough room to up to a 2″. With either bike, however, I would call them to make sure as they are both great with their customer service.

          • James Talmage

            I called WOOM, and Mathias suggested a max 1.95″ or 2″ tire max for the WOOM 4. It would almost certainly fit a 2.1″, but you are adding a lot of rolling resistance, and you are getting diminishing returns at that point.

            Also, the newer WOOM 4’s have 1.5″ tires, just like the Islabike. I am still debating whether to upgrade to just 1.75″ or all the way to 1.95″.

            Mathias at WOOM is totally awesome. After our conversation, he’s “researching what is available on the market” to find a tire tread he likes for the off road riding I described during our call. That is just really awesome customer service.

      • bs

        Great article, very helpful!

        There is a significant difference between the age and size that the two manufacturers state for these two bikes. Islabikes Beinn 20 Small is for age 5+, inseam 18.5″, height 44″, and the Woom4 is for age 7+, height 46″.

        We ride a lot of singletrack and pump/jump tracks. My 5yr-old is advanced and is constantly spinning out on his hotrock 16 and needs gears. Since he’s small (18″ inseam, 43″ tall), the Islabikes Beinn 20 small is probably the only option we have unless we wait another year or so. Are there any other 20″ bikes that could work for him? I’m slightly concerned about Islabikes’ statement that the bike is for smooth surfaces and no jumps. We ride some fairly rough trails and kids love ramps & jumps.

        Also I think there’s a typo in the crank info, I believe you meant 114 instead of 144.

        • Wow, I never picked up on how different their recommendations are, thanks for pointing that out, plus the typo about the cranks, as I clearly missed that as well. For bikes, my son rode the Islabikes 20″ Small for years on single-track and at the pump track and did great, so I think it is still worth considering. It is certainly not a downhill bike by any means, but for standards trails, he never had a problem with it. I will say, however, that the grip shifters eventually became a challenge. When got more aggressive in his riding and learned to really shift (age 6), he would often try to shift to fast which would shift the handlebars causing him to crash. This summer, he switched over to a trigger shift on the WOOM5 Supra, and once he got used to them, he did awesome. The wider tires of the WOOM also helped out.

          Some other options I would consider would be the WOOM4 Supra, the Spawn 1.0 or 2.0 (2.0 heavier as they have a front shock) and the Trek Superlfy 20″ (you could at least try it out in a shop first). I also just learned about a new brand of bikes, names Guardian Bikes, which only makes 20″ bikes right now and focus on lightweight, lower center of gravity and a dual braking system to prevent endos.

          Hope that helps and if you can, I’d love to hear what bike you went with and why. Thanks!

          • Alejandro

            I’d like to get my kid in one of these two bikes as soon as he is big enough. So what I’d like to know is which one is smaller, the Woom 4 or the Beinn 20s.

            Minimum seat height is almost identical, what about other dimensions?
            The Woom 4 seems shorter (horizontally, seat to handle bars) in the pictures, but it’s marketed for 7+ vs 5+ for the Isla.

            Thanks for an awesome site.

            • The WOOM4 has a shorter reach than the Islabikes, which changes the geometry of the bike, but not necessarily the age range. The WOOM4 is designed for more of a beginning rider than the Islabike, so the rider sits more upright, hence the shorter top tube (the tub that connects the seat post to the handlebars). Both bikes are sized for the same size child, but the WOOM4 is for a more timid rider while the Islabikes a more aggressive. Size wise, they are the same. Hope that helps!

      • Daniel Fulop


        Great review and website! Thanks a ton for the awesome info!!

        I’m looking to buy my 5 y.o. daughter her 1st pedal bike. Her inseam is ~18.7″ and she is ~42.75″ high. She used a Strider balance bike for a about 2 years on and off; she would gain moderate speed and balance on it, but never go too into it. Then she moved on to a Giant tricycle, which she used a ton. In the last ~6 months she’s been riding a Burley Kazoo trailer bike with me several times a week. She’s super into it and has been asking for stand-alone pedal bike. She’s pretty fearless, though easily frustrated.

        I was between the Cleary Hedgehog (with riser bar to lessen the aggressiveness of the geometry) and the Islabikes CNOC16 (WOOM3 is a little too expensive, and we cannot wait for the back-order because we want it for her birthday in ~2 weeks) …until I measured her inseam and realized that she is actually at the beginning of the Islabikes Beinn 20 small’s inseam range, so that that bike would last her a lot longer! …whereas she could outgrow the CNOC16 in ~1 year. My sense (perhaps unfounded) is that she could get about ~1/2 year more out of the Hedgehog than the CNOC16, since the former has a longer frame and seatpost, etc.

        What would you recommend? Would it be crazy to have her start on the Beinn 20 small as her first full pedal bike? She could start out using a single gear and only learn to shift gears in a few months once she’s mastered balancing and braking.

        • My son started on his BEINN 20 Small when he was five, so I do think it is an option, but I do have some concerns. The main issue is that the 18.5″ listed on Islabikes website is the length from the seat to the pedal, not the ground. The minimum seat height of the bike is actually 21.5″. As a result, she will only be able to touch the ground with her tippy toes on the bike. Since she is fearless, she might be okay with this, but she won’t be able to really start or stop the bike on her own for a while, plus, she won’t be able to stop with her feet, which she will want to do at first. So it really depends on how you think she will react on the bike. If possible, I would take her to a bike shop and see how she feels or reacts to a bike in which she can’t touch the ground with her full foot (make sure the training wheels are off to prevent a false since of security). The benefit of the BEINN is that is geared if you plan on doing more than neighborhood rides.

          The Hedgehog would certainly fit her better as it’s minimum seat height is 16″. If you put a riser bar on it, I think it would be a great start for her size wise (and it you do, please pass along a pic if possible). I will say that the max height of 26″ on the Hedgehog is really pushing it as she will need a larger bike before she gets that tall.

          • Daniel Fulop

            Hi Natalie, thanks a ton for your feedback. We were close to getting a Hedgehog with the riser bar, but in the end we went with Islabikes for a number of reasons. After talking to the Islabikes folks they clarified that, as you say, the Beinn 20 small would be too big for her. So, we got her a CNOC 16, which arrives tomorrow!

            • Awesome! Islabikes are amazing. Hope she loves it!

      • Jaime

        Help! Can’t decide on the Beinn 20, Woom 4 supra, or the Spawn Savage 1.0. Do u have any reviews of the Savage? I have a 6 yr old, 18.5″ inseam, and 45″ tall. Been riding a CNOC 14 for a few years now. Live on a gravel road but wil also ride on paved bike trails. Hope to do a little single trak. He will pro ride around our yard as well. Do have a 4 yr daughter who started riding the CNOC last year. Thanks so much
        Oh, do u think the Carbon on the Supra could cause problems with kids throwing their, bikes down etc?

        • Glad to help. As far as the carbon on the Supra, we haven’t had any problems with it, and it you do, I’m sure WOOM would work with you. I actually haven’t had a chance to review the Spawn bikes yet, but I have only heard great things about them. I can’t seem to find the weight of the Savage, but the seat heights look to be the same as the others. As for which is best, if you were mainly using it for single track, I would go with the Savage, but since you are mainly planning on using it around the house and paved trails, I would probably go with the WOOM4 Supra. It’s geometry isn’t as aggressive as the Spawn, which will make is more comfortable for rides on paved trails and around the house. If you are mainly doing paved trails, the the BEINN would be best.

      • amanda

        I’m seeing the current woom4 on Amazon listed with the twist shifters, not the levers. Maybe this is new?

        • Yes, the WOOM4’s now come with the grip shift versus the trigger, so I need to update my review. As for the Islabikes, my daughter and son both did a lot of mountain biking on the standard tires found on the Islabikes BEINN Series without a problem, so I would let the tires keep you from the Islabikes if it is a better fit.

          As far as size, my son went from an old Hotrock 16″ to the BEINN small, but could have easily gone to the BEINN large. Going from a 14″ to a 20 small, might be a stretch, but as long as she is a confident rider, I certainly think it is doable, especially with the BEINN 20 small or the WOOM4.

      • jane

        Hi — I’m looking for a bike for my tall six year old in Maine, where we live on a hilly gravel road and can also go biking on the carriage roads in Acadia National Park. We won’t ever be biking on sidewalks, so this is just for dirt roads and trails and carriage roads. I don’t know what a single trak is that folks refer to below. He has been on a pedal bike since he was 3 and leans aggressive — he is trying to do all manner of tricks on his scooter these days. So I am torn between the bike with the break system that prevents endos? and the most mountain bike like bikes? Any thoughts?

        • Glad to help. Both the Guardian (the bike that prevents endo) and the WOOM4 are great bikes, but if you are riding more hills, I would stick with the WOOM4 as it has a lower gear ratio that makes it easier to climb hills. If your son is an aggressive rider and doesn’t mind powering up hills, then I would go with the Guardian as an aggressive rider would also benefit from the dual-braking system.

          As for the type of riding you are doing, it wouldn’t be called “single-track” as that implies that the trail is only wide enough for one rider at a time, but the needs are very similar. You will want a lightweight bike with knobby tires with a more aggressive position (not too upright like a cruiser bike). Braking will also be important, so dual-hand brakes (or the Guardian system) is a must.

      • James Talmage

        The WOOM4 is just amazing. I got it for my 5 year old as his first pedal bike (on a Ridgeback Scoot balance bike since he was 3). He was pedaling up and down the block without stopping within 10 minutes of assembly, and did an 8 mile paved loop with moderate hills four days later. Within a three weeks he had graduated to single track, and has more courage than his Dad in some sections (I broke my hand in a bad endo last year, and I am still a bit timid).

        I think the smaller cranks and kid specific geometry is probably the best part of these bikes designed specifically for kids. The lighter weight is important (and I got really caught up in that at first), but after watching other kids ride bikes with bad geometry and cranks that basically make them kick themselves in the butt, I would definitely prioritize those over weight. Yes, a lighter bike is better than a heavy bike, but I feel it’s the geometry that allows my son to out-pedal kids nearly twice his age.

        As for Wooms switch to the grip shifter, I am not entirely sure it’s really better than a trigger. My son is constantly looking down to see “what number” he is on. He really likes being on 8, even when it is maybe not the best choice (he just wants to go fast, all the time). Also, the looking down distracts him when he should be concentrating on riding. I have considered blacking out / taping over the view window, but he probably won’t take that well. Also, I feel the grip shifter encourages him to make big changes when he should be making small ones, he can really easily go from 1st to 8th in one twist, and vice versa. A trigger shifter that forced him to move one gear at a time might encourage him to find optimal middle ground. All that said, he’s never used a trigger shifter, so this is all speculation on my part.

        Gearing: I am considering getting him a smaller front ring. For the single track we do, he just needs a slightly lower gear for some of the climbs, especially when there are lots of roots. One problem with their decision to pack 8 gears onto such a small bike, is that it creates a VERY steep chain angle when you are in the lowest gear, and it only takes a small bump to derail the chain. It got to the point where my 5 year old was faster at re-chaining his bike than any adult I know. I took it to the LBS, and they added a chain catcher (the Deda Elementi Dog Fang – approximately $5) to the seat tube. It has reduced derailments probably 10 fold. I highly recommend if you are taking the Woom 4 on rough terrain. Woom really should just consider just making it standard.

        After a few times out on the singletrack, I was concerned I made a mistake, and should have gotten him a suspension bike. After some research, it doesn’t seem anyone makes bikes this small that have “real” suspension forks on them (every suspension I’ve looked at is way too stiff to be effective for a small kid, has no adjustments, and adds a ton of weight). It looks like there is room for much beefier tires, so I am definitely considering that. I have had him running well under the recommended pressure on the mountain bike trails. That has worked well so far, but he did get his first pinch flat last weekend. I’ve considered doing a tubeless conversion, but I don’t even run tubeless myself and they seem like a lot of maintenance.

        Other thoughts:

        IMO, it would be nice if Woom gave you the option for Presta valves when purchasing. I was all set up for Presta, and had to get a new portable pump that supported both to ensure I could service his bike on the trail.

        I can’t believe how close the derailleur gets to the ground. He is going to destroy it on a rock or root someday soon. I’ve already seen him smack the chainring hard on a number of things (it’s obviously high quality – can’t believe it’s not destroyed).

        The low stepover height is awesome. He now dismounts on the fly to run up steep sections, and can jump back on mid stride. They really did put a lot of thought into the geometry of the frame.

        Minor annoyance – the end of the grips are hard plastic instead of standard slip on grips that fully cover the end of the handlebars. The plastic caps at the end are painted black over white plastic. It took about 10 minutes for the ends of his bars to become chipped and looking really beat up. Most of the other damage my son has done to the bike I write off as him being a maniac, but this just feels like a simple oversight. From your pictures, I think they might have changed grips when they changed to grip shifters.

        Funny – When I had it at the LBS to address the derailment issue, the mechanic lost his mind over how light it was. He made everyone in the shop lift the bike, and compare it to theirs. I think he might have inadvertently talked another parent in the shop out of a sale.

        I would really love to see reviews about kids mountain bikes. It looks like you are working on some. Is anyone else reviewing kids mountain bikes (I haven’t found anyone).

        Have you considered reviewing additional safety gear? Gloves, pads, etc? My sons knees and elbows have layers of scrapes at various stages of the healing process, and Mom is about fed up with that.

      • Owen Paulus

        Hi there! I’m looking for my daughters next bike and trying to decide between the Woom 4 and Isla Beinn 20″ (large or small). She’s turning 5 and current rides a CNOC 14 (but is too big for it!). She is tall for her age (45″ tall and about 19.75″ inseam). She’s been riding the CNOC since she was just over 3 and is a confident rider on lots of terrain and can’t wait to have gears to climb more hills. I’d like to jump to the biggest bike possible, but I’m worried the Beinn large might be just a little too big and she’s already part way in to the range of the Beinn small. The Woom 4 size charts aren’t as detailed, but based on it’s target rider height of 45″, it seems like it might be just the right fit. We love our Isla, but your glowing review of the Woom and it’s range of fit is pushing me that way. Thoughts?

        • They are both great bikes. My son started out on his Beinn 20″ Small when he was five, so the jump is certainly doable. With an almost 20″ inseam, she should have no problems on either the WOOM4 or the Islabikes BEINN 20″ Small. Between the two, the BEINN is slightly more aggressive in positioning than the WOOM4, but are you pointed out, the WOOM seat is slightly taller. In addition, it’s maximum seat height is 1.5″ taller, so I would probably go for the WOOM4 as it would allow for more room for growth. Then again, going back to the positioning on the bike, the more upright WOOM will won’t be ideal if you plan on riding more hilly terrain. If you are, then I would go for the BEINN Small.

          • Owen Paulus

            Thanks for the extra details. You mention in the review that woom is better for aggressive riders, but your comment says the woom seat position isn’t as aggressive or good on hills. Could you elaborate?

            • Humm, well you’re right, I certainly provided some contradictory info. Looking back up at the review and the comparison pics, I realized I got myself confused. The geometry on the smaller WOOM’s are much more upright than those on the WOOM4 and 5. As shown above, they are essentially the same as the Islabikes. The main reason why the WOOM4 is better for all-terrain riding is it’s wider tires, which provide more traction. At the time of this review, the WOOM4 had trigger shifters, versus grift shifter on the Islabikes, but WOOM has switched over the grip shifters as well. As a result, they are both still amazing bikes, but the tires on the WOOM would lend the bike better towards all-terrain riding. In terms of hills an body position, there shouldn’t be a noticeable difference. Sorry for the confusion.

              • Owen Paulus

                Awesome, thanks. Our Isla Cnoc has been great, but I’m gonna try the woom this time! Your site is awesome – I’ll be sure to follow your link to purchase. Hopefully that gets you some referal credit!

              • Thanks and glad to be of help!

      • Stephen R

        OK, I know there a lots of comments regarding “what’s best for my lil one” but I have to ask some specifics that I haven’t seen previously…
        My son is 5.5yrs old 46″ tall and 19.5″ inseam. He has been riding his 16″ Specialized hotrock since he was 3.5yrs old and also has an old school Free Agent Lil Homie as a second bike that I bought used. I bought it so he could learn how to ride a free wheel and use finger brakes.
        We ride both single track trails (mild and he walks the more advanced technical areas) and road. He likes riding fast on the rode and spins out of his hotrock very easily. He can average about 9-11mph on 6-8 mile rides but spins as fast has he can. He wants to do organized bike rally’s with us and join a triathlon team when he turns 6.
        We are looking for a bike that is versatile enough to change out tires for road/off-road single track. We also need the bike to last long enough for him to grow into road/mtb specific bikes on the next purchase.
        Looking at the Woom4 (possibly supra) and the Beinn (not sure on large vs. small).
        On a side note, his older friends have big box 20″ bikes that he can ride (tip toes on ground only). Need help!! If there is another option better suited please let me know.

        • Stephen R

          I also noticed that the newer WOOM’s have 110mm cranks. How does this play into the decision? With the shorter cranks, will my lil guy have a higher chance at spinning out of his gears? Thanks again…

          • Awesome. Loving the riding your little guy is doing. As a 5yo my son was riding his Islabikes BEINN 20″ small for miles on single track trails for miles, without a problem. He also did just fine cruising bike paved bike trails with it. On a geared 20″ he won’t have the spinning out issues and both the WOOM and the Islabikes offer plenty of range. Between the two, they both have Kenda Small Block 8 tires on them, but the WOOM’s are slightly wider than the Islabikes, making it better for all-terrain riding and the Islabike better for road. The differences are minimal though, so I would go for the bike that fits him best based on inseam.