Before my 20" commuter I ran a 24" x 3.0 /90mm build and it’s a really good micro machine. A bit less portable than a 20"/75mm build but still a very good balance of practical and fast for joining the small wheel smaller crank gang
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So I have an extra 36h aluminum hub and extra set of 75mm cranks (2 currently ownwed) and are ispiring me to try an event smaller wheel build for fun lol
Those are sone really good stats and great example of the micro machines lol.
I agree. 24"/3"/89mm is so much fun! Just on the point where I still feel confident without brakes, although it’s rather awkward going steep downhills. I rode this just last week!
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Ye 24"/75mm is very nice. 90mm would probably be more practical around town but apparently when you order those from Sweden you get 100s which with their enormous torque will destroy your hub.
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It seems like the winning formula is small wheel, small crank, bigger tire across most of our builds.
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Agreed, the weight of the tire compensates the lack of inertia of a smaller wheel. And the bigger tire absorbs the cracks and (small) holes on the ground.
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So for an experiment I put a 300g 2" tire on my 20" and it had no weight to keep the speed going. My current maxxis tire is 500g-650g (I forget off the top of my head) and I had an 800g bmx tire too. Paired with a 400g rim and tpu tube it was a much better set up. So 1kg of wheel weight seems to be a good starting place or floor for those who are nerdy on these things.
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I am not sure of the exact weights but my impact athmos weighs 5.9 kg and when I took off the wheel it felt as though more than half was in the wheel. The cranks and pedals might be as much as 1kg themselves, but still a decent amount in the actual wheel
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I am very curious to understand more about your and @pierrox 's “bad habits” comments above. What sort of bad habits are you referring to, and does riding smaller wheels and or cranks help you to sort of eliminate those?
I’m wondering if regular small wheel riding helps develop better efficiency for example?
( you certainly do have to pedal a lot more!)
Now we just need a follow-up experiment to this one:
Wonder if anyone here is willing to take a stab at the world’s heaviest 16 inch wheel 
I don’t have a 16" but did add about 9 lbs (4 kg) to my 24" with a similar results. It rolls over bumps more reliably.
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They mention short cranks relative to the wheel size.
One of the first times I rode my Schlumpf in high gear I UPD‘d because I started to lean forward and when I was at a point where a quick correction was needed, I simply couldn‘t accelerate the wheel quickly enough to regain balance. Instead I got ejected (if I grabbed the seat at that moment things may would have evolved differently).
If you‘re riding a setup with a high [total gear ratio] (New concept: Total Gear Ratio - #23 by saskatchewanian) you have to correct sooner / ride smoother compared to riding a uni with a low total gear ratio.
When it comes to riding a small wheel, every bump and obstacle becomes harder to overcome. So you have to ride more attentively and anticipatorily.
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I did a rebuild of my 24" using various old parts and some new 89mm cranks. It’s not micro - but I can’t see myself riding a smaller uni for any reasonable distance
It’s a Nimbus 48h hub, Alexrims/DM24 rim and a Maxxis Holy Roller 24"x2.4" tire.
I was quite surprised how well it rode - also on the uneven gravel parts of my 9km route.
Average speed (14.3km/h) was also not much lower than on my 29" with 110mm.
I never ride brakeless so that was to be honest my biggest fear. But even on the longest steepest descend around me I managed to ride (very slowly) from top to bottom.
I’m tempted to try even shorter cranks and add a brake but I’m not sure I’m ready to do that kind of investment in a micro machine…
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To a degree yes, but there’s a few levers we are playing with for these builds.
- Cranks size
- Wheel size
- Wheel weight/tire size
Crank size: smaller is faster, longer more control. *with adequate practice
Wheel size: smaller doesnt roll over as easy, so more energy or speed is needed. But smaller wheels are easier to accelerate.
Tire: more control and momentum with a bigger tire thats heavier, but it’s more difficult to accelerate or decelerate as the weight goes up. This helps that once you’re up to speed it’s easier to maintain speed through bad terrain requiring more control.
I’ve had a 20/4.0 and 2.3/75mm set up, and a 24/3.0/90mm set up and found the performance on both to be similar. I’ve had good city riding where I could maintain 15kmh average on both and found light muni on both not to be horrible.
Add in a handle and you have another way to increase control too allowing you to go faster or raise your potential top speed.
Though I’ve not done a side by side conparison my memory is my 20" and 24" rode fairly similar through the Canadian winter I take them through, both were not stock builds though as I like to customize my unis.
Additional point too but frame stiffness is important. My Flanz frame vs my URC XS frame have a noticeable difference in flex and control when we had a recent 40cm dump of snow.
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You‘re certainly an expert when it comes to riding small wheels and short cranks, so I won‘t disagree with what you say.
I didn‘t take the parameters you mentioned into account but referred to the fact that a smaller wheel „sees“ a given obstacle differently due to the attack angle (I hope you can figure out what I mean). To exaggerate a lot: a big wheel is lifted in rather gentle way while a small wheel contacts the same obstacle like hitting a wall.
So, when tire size and pressure as well as total gear ratio are in the same ball park, the bigger wheel will roll over obstacles more easily.
Loosely related: Many years ago I used to play unibasket every now and then. I was the only one with a 20er, the others rode 26ers and were of course way faster than me. But I was quicker to accelerate, decelerate or taking turns. Plus I was the only one able to pick up the ball from the floor, at least sometimes, while according to our rules the others had to wait for a trainer to arrive and pick the ball up for them, if they couldn‘t do it themselves; so overall my small uni was the key that enabled me to score more points than other players. Now all of that was on a super smooth wooden floor, of course…
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Mine is I drift to the left, meaning my down stroke on the left foot is stronger, and usually accompanied with a slight pelvis left tilt. Which my right doesn’t do the same way and is less under control. So sometimes it’s throws me off balance if I don’t have the time or position to counter a left move - hard to write this sort of description!
But it boils down to not enough weight on the saddle. As the small wheel just won’t dampen or smooth out the approximate riding, you have to work on it to become smoother!
Completely agree on bigger wheel and tbe attack angle all other factors being equal. I just love nerding out on how complex something so simple as a uni can be.
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