knees and hills

[Karl42]

Welcome to the neverending quest for low gears and short cranks. Just when you think you have it all figured out, the bicycle industry will have changed all the standards that you've just learned and you have to start over
I started with 165mm cranks on my V20, got knee problems immediately (with 79 cm / 31 inch inseam length). Then I switched to 152mm cranks and my knees are fine. My average cadence is fairly high at 100-110rpm. Maintaining a high cadence on steep hills requires very low gears that are not easily achievable with standard road components. A standard road setup of 50t/34t crank with a 11-32 cassette will give you a lowest gear ratio of 34/32=1.06. For me, this wasn't nearly low enough to spin up steep hills, and you'll find other forum members here that also use much lower gear ratios.
So you either have to make the small front chainring smaller, or the largest cog on the cassette bigger, to get a lowest gear ratio of 0.9 (34/36) or even 0.8 (34/42). Or you can use MTB components, where you can go even lower. It is possible to use road shifters with MTB derailleurs and cassettes with the help of some aftermarket parts from companies such as Ratio Technology, or when using the latest electronic components that let you mix road and MTB parts.

 

[bret]

Can you fit fenders with 2" tires?

I have mounted 60mm fenders on my 2021 Q45. I can't speak to other models, though.

Regarding motors, there are 250W geared hub motors that can be placed in the back wheel to meet your expectations. Grin Technologies lists several, and I trust their vetting for quality and reliability.

Cruzbike is making a transition to thru-axles, and this is a critical item - there are very few motors sold which work with thru-axles yet. There is a wide range of geared hub motors for quick-release or bolted axles.

My Q45 has thru-axles and a Grin Technologies All-Axle motor. I am currently using ~5.5 watt-hours per kilometre, and that includes some use of the throttle to boost up hills and I get 4.5% regen to save on brake wear (once I trigger the switch in the brake lever, the motor turns into a brake to slow the bicycle).

I have a cadence sensor on the bottom bracket to tell the motor what to do - torque sensing bottom brackets are available, but I want to avoid loads on my ankle, as you might wish to avoid on your knees. I can shift down and spin and the motor does all the work going uphill, or I can shift up a bit and take as much of the load as I want.

 

[bladderhead]

34/42 is a high gear. My chainring is 38 and my biggest cog is 51. With that cog, the same ratio as 34/42 requires a 48 ring. If my sums are correct. If you try my bike it will seem ridiculous. Your legs will be going like nobody's businesses and the bike will be hardly moving. But then you can winch yourself up the side of a cliff without any discomfort. This feels good. Until some bastard flies by on a Trek, standing on the pedals. Let them go.

My cranks are called Microline, made by a company called Redline BMX. My cadence is fast. 100 I think. I had to teach myself to do this.

 

[DavidCH]

130mm

Eh? Your knees must be really fragile...

130mm that must be a record? Any smaller anyone?

 

[McWheels]

Wider tyres are good, I have them on my S40, plus a nice slim rack which holds pretty much anything.

20200818_122742

• McWheels
• Aug 18, 2020

The final iteration with B&M light mounted to boom clamp and wired through the frame.

 

[bladderhead]

My knees are a bit dodgy, but the cycling does not effect them. Fortunate, because I would badly miss cycling. I cannot walk very far, but that matters less to me. @LarryOz is right. Cycling is knee-friendly if you make it so.

The blue cog of @McWheels looks so cool.