Miele Man

Please tell us the make of your cassette as I for one have never heard of a ten teeth cog.

Cheers

BlazingPedals

You haven't seen my legs.

BlazingPedals

^^^ this. You first need to figure out what your max sustained speed is, then determine what gear you'll require to to that speed at your 'ideal' cadence, and then from there you need to determine how many gears *above* that you want to keep as reserves in case of downhills and tailwinds (if any.) There is no perfect gear set, only a good one for your power capacity and aerodynamics.

For me, I try to keep one gear higher than what I can sustain in a short flat sprint (if that's not redundant to say.) That's in case of tailwind or downhill. I hate running out of gears.

BlazingPedals

Well, yes, but then it never had to compete with the Travant for our affections.

bakes1

Shame on anyone that replied to this pile of feces; for any reason.
Myself included ofc

CliffordK

Probably an 11T or 12T on a standard 8 speed cassette.

SRAM puts a 10T on many of their MTB cassettes. But, with a huge sprocket range, and I don't believe in 8s.
https://www.sram.com/sram/mountain/p...-dome-cassette

There are a few small wheel parts that also incorporate a 9T or 10T sprocket including the Shimano Capreo (9s). I think I also encountered a modified Campy cassette somewhere using a 10s small sprocket for small wheel bikes.

Any of them can be built into a road bike. But it doesn't just happen by accident.

Whether going to 9, 10, 11, or 12T is beneficial on a road bike is something that one can argue until they are blue in the face.

The benefits on small wheeled bikes is that they compensate for the wheel size, and allow using more standard chainrings. On an MTB, the smaller sprockets allow a greater gearing range while keeping the size of the derailleur in check.

1 to 4.2 gearing: 10-42 (32T) <==> 11-46 (35T) <==> 12-50 (38T)

Retro Grouch 

Is that the car that didn't come with a reverse gear?

Flinstone

So being kind of a numbers guy, I ran some numbers on this 30mph business. There were some claims here that this requires 650 or 700 watts. Three different online calculators tell me it's more like 500 to 550. I don't know what to trust. Those calculators seem to work well to me. Anyway, at 600 W to reach 30mph at 90 rpm requires an average force on a pedal with 170mm crank arm of 38 kgf (the "weight" of 38kg or 372N if you prefer, it's 83 lbs if you like imperial units).

That's a pretty big force to be pushing around with one leg at that speed. Sure you could try to spin at 130 instead. Good luck pushing 26kg (57 lbs) around at more than twice a second per foot. These are essentially single leg numbers. Think of pressing 76 kg (167 lbs) on leg press machine. 8 reps is fine.. easy. Now do it 90 times in a minute.

fietsbob

Shimano Capreo cassette and freehub . CS-HG70-s Cassette 9-10-11-13-15-17-20-23-26 tooth sprockets.

+ the exclusive hub to use it: FH-700 Freehub. they are produced for Mini velos and folding bikes with small wheels like 451 - 20"

The Shimano Capreo hub and Cassette

CliffordK

The Messerschmitt KR175 had an ingenious reverse.

It had a 1-cyclinder engine that could be run forward or in reverse. So, to go backwards, simply stop the engine and start it backwards. Thus, the 4 forward speeds become 4 reverse speeds