Unicycle and bicycle Hill climbing - Gear ratio comparison

Videos
1

Went for a ride around Akuna Bay, north of Sydney on my “commuting” Unicycle.
It has a 36" Wheel & 110mm crank length.

See below video showing Bicycle and Unicycle Hill climbing.
From my searches through this website for Unicycle gear ratio charts and also looking at Bicycle Gear ratios on the interweb, I get the below comparisons of gear ratios.

Could anyone give their confirmation / insights?
The comparable bike gearing seems not right.

Comparing Gear Ratios for this Unicycle and a Bicycle with Front chain rings 52/39 and rear 11 speed sprocket cassette 11/34,

The gear ratio of the Unicycle with 36" wheel & 110 crank = 4.33

Similar gear ratios for Bicycle with 27.5" wheels & 170mm crank.

  1. Front Chain ring 52 / rear sprocket 11,
    Gear ratio =4.73

  2. Front Chain ring 52 / rear sprocket 12,
    Gear ratio =4.33

  3. Front Chain ring 52 / rear sprocket 13,
    Gear ratio =4.00

  4. Front Chain ring 39 & rear sprocket 11,
    Gear Ratio= 3.55

Video link:

2

Those bike ratios don’t include the wheel and crank sizes, just the chainring and rear cog.

edit: (so, since the radius of a 27.5" wheel is about 2x the size of a 170mm crank, you would need to multiply the bike ratios by 2).

3

Not understanding the first part of your post… but did the bike catch you?

4

The gear ratio of a unicycle is 1.00 with any cranks.

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5

In order to get the same ratio of crank circumference to wheel circumference of a 36er with 110mm cranks I figure you would need a sprocket gear ratio of about 2, or 39 teeth on front and 19 teeth on the back.
That is about mid range of the 39 tooth sprocket and that makes sense. Geared bikes are always faster and slower geared then a uni.

6

He didn’t catch me,…
I’m really satisfied with that… Actually I didn’t even know he was there until I stopped just out of frame…
It was on a 8% grade Hill.
Not sure if he was trying to catch me.

Anyways, I thought the video was interesting having both of us in frame.

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7

If you want to compare gearing on a bike and a unicycle, use gain ratios since these take into account crank length

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8

And there is even a gain ratio calculator that includes such oddities as 36" tires and 110mm cranks.

Best website everfor cycling nerds.

No Schlumpf hub, but you can just put 1 and 1.5 as Chainrings and 1 as your sprockets to get those results. A 36" Unicycle with 110mm crank is calculated to be a 4.1 gain ratio.

27.5"x2.5 bike with 170mm cranks adds up to these Gain ratios with 52/39 chainring 11/12/13 sprocket:

52 39
11 10 7.5
12 9.1 6.8
13 8.4 6.3
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9

There are 3 Schlumpf hubs in the “Internal hub” dropdown. Unfortunately, none seems to match the real ratio of our geared hub.
By the way, as far as I remember, the high-gear ratio is of 17/11 ≈ 1.5454 - which is a bit higher than 1.5 :grin:
To achieve that on the calculator, 11 and 17 as Chainrings and 11 as sprocket.

At 60 RPM on a 36er, that’s a difference of about 0.4 km/h.
Screenshot_20230408-163742~2
Screenshot_20230408-163804~2

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