5

I'm confused about the speeds amount in my bicycle. There are totally more than 20 different speed configuration on my bicycle, but are there any practical use of such speeds as 1-1, 1-2, 1-3, 2-1. What are that crazy places to use these speeds in real world?

Imagine, we can mount top 7 speeds of 10-speed cassette. Would it make sense to avoid slowest speeds since they are unused?

P.S.: The smallest speed i have ever used it 2-3 and that was a crazy steep uphill ride with plenty lot of small stones on it. What is your lowest speed?

  • Your "2-3" gear description makes no sense sorry, the ratio depends on tooth count. Can you count the teeth? – Criggie Jul 25 '17 at 12:27
  • 1
    I assume you're on a mountain bike ("small stones", "crazy steep"). But round here we've got roads at over 20% (only for a couple of hundred metres at a time) and the bottom gears are definitely useful then. My old commute required my full gear range every day (from climbing 20% to keeping up with cars on a downhill to catch my lane/turning) – Chris H Jul 25 '17 at 14:40
  • 1
    @Mathlight I tend to use my middle ring when riding on the flat at slow walking pace, down to about 2km/h. I don;t use full pedal stroke though, just a little nudge of one pedal every few seconds then back to horizontal cranks (I don't have to worry about toe overlap) – Chris H Jul 25 '17 at 14:42
  • 1
    There are some useless combinations (for riding), but they aren't the lowest ones -- for example, small chainring - small cog is used when you're servicing a bike, but you should never ride in it. – Batman Jul 25 '17 at 14:59
  • 1
    Batman's comment was small (inner) chainring and small (outer) cog. This places a lot of lateral stress on the chain, and may require the derailleur to perform some contortions to take slack out of the chain. – kdgregory Jul 27 '17 at 1:59
2

I ride the trails and they are steep as heck, and torturous. 30% - 45% climb, and they aint smooth climbs, most of it is rocky. Hence this is when the light gear comes into use.

7

You're right - there's an awful lot of overlap between the gear ratios offered.

I dunno about your riding, but I have a 21 speed (3x7) and the lowest gear is 26/28 (that's a 26 tooth front chainring with a 28 tooth big cog on the back block) and I occasionally want one lower on the super steep climbs.

At the other end I have a 52/12 and on a downhill I am spinning out too soon.


https://www.whycycle.co.uk/images/gearRatios.png

This shows that 28/16 is about exactly the same ratio as 48/28.

You might choose to be on the big chainring if you're about to go down hill or flat and smooth, but if the next section is an uphill you would want to be in the little chainring ready for the grade.

So the middle chainring is useless? No - without that the front mech would have to lift the chain from the small to the big chainring, and that's a gap of 20 teeth. Most derailleurs can cope with 13 teeth gap, not 20 teeth.


To make best use of your gears, you want to ride at a pedal cadence of ~80 RPM. So pick a gear that lets you spin the pedals at about this speed. Too slow and it hurts your knees.

Many riders live in the middle ring and use the rear mech to get gears, only changing front ring in the extreme of headwind/uphill or downhill/tailwind. Personally I live in the big ring all the time, until it gets steep.

Changing gears will also help spread your overall wear, and lets you get moving quicker from a stop at the red light.


Edit: Here's a segment where 26/28 is only just sufficient: https://www.strava.com/segments/9230838 Strava says the grade is in the upper 30's percentage, and having ridden it I'd agree. The main problem is keeping the front wheel on the ground.

  • 1
    Thank you for giving an comprehensive description about gears usage. But mostly know the information, you have provided. I want to see if there is a practical situation, in which something like 28/28 is used. For example images of the locations or descriptions like "uphill with 30% angle". – fixerlt Jul 25 '17 at 12:39
  • 1
    @fixerit Depends on your cadence, power, and incline. You should try a 10% gradient, you'll quickly be wishing for even easier gears than 28/28. – sjakubowski Jul 25 '17 at 14:01
  • @fixerlt You have a road bike with a 1:1? I am having trouble believing that unless it is touring. What you need will depend on your condition, load, desire, and slope. If you want different gearing then buy it. – paparazzo Jul 26 '17 at 0:34
  • @Paparazzi low low gear on my bike is not 1 : 1, its even lower at 1 : 0.93 criggie.org.nz/pictures/bikes/mongoose/… showng the 26 tooth granny, and criggie.org.nz/pictures/bikes/mongoose/… shows the original cassette which was 11-25. Current cassette is a 12-28. Calculator tells me that 26/28 is 0.929 hence 1:0.93 ratio – Criggie Jul 26 '17 at 6:07
  • 1
    @fixerlt Physical condition. You are ranting. There is not a one size fits all in gearing. Adjust to what works for you. – paparazzo Jul 26 '17 at 7:32
1

It really depends on your usage scenario. I just returned from a tour with moderate climbing and 1-1 (11-22) was not "low" enough for me on decent grades with 25 kilos strapped to the back of my bike.

However, back when I was commuting, I just ran a 1x9 on the 52x(11-32) with a decent uphill climb one way. In this setup I wish I could have gone "higher".

I agree in most situations the available standard ranges are unnecessary.

1

Separate answer - I use a 20" folding bike as a tractor to pull around a trailer.

When the trailer is loaded, the bike has a lot of weight to get up to speed and then to slow back down. Starting from stopped on the big ring even in 32 on the back is very hard work.

The bike in question has a triple on front with 48/38/28 teeth, and the rear is 11-34 8 speed cassette. Combined with 20" wheels, gives this bike an ultra low gearing of 15.4 gear-inches.

You can play around with combinations at http://www.sheldonbrown.com/gear-calc.html

Own work.

So this bike is 18 kilos, I'm 100, add a trailer at 8 kilos is not a lot more, but add 90 kilos of load on top and then you've essentially got a bike that outweighs the rider. A small incline up to a railway crossing was hard work, and even crossing through some traffic lights, the camber of the cross-road required a drop in gearing.

Braking with the heavy trailer was reversed - normally road braking is 90+% from the front wheel, but with a hefty trailer it just pushes the whole bike over the front contact patch. So 90% of the braking here is done with the rear wheel.

At one point I was standing astride the main bar with the brakes casually on, and teh trailer started pulling the unladen bike backwards down a slight slope. So I had to stay seated in the saddle even when stopped.

tl;dr Low gearing is very handy when towing, exactly the same as in trucks.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.