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I have been told many times but still cannot explain


womanofdulwich

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I haven't a clue either.


I asked the guy who serviced my bike to put my gears on the right setting for what he thought I'd need.......


And I never change them. Uphill, downhill, whatever. Don't dare in case I mess it up when it's working fine.


Just looked and it's L on the left, 7 on the right. (which means nothing to me!)

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The guy who serviced my bike adjusted something to stop the chain falling off (because something was too loose)

I don't know what it was, or what he did but it worked perfectly and the chain hasn't come off since.


I suggest you ask in one of the bike shops. Hopefully they will know what to do. It only took a few minutes.

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I explained this to my kids recently, so I'm happy to have a go.


Imagine a kids trike, where the pedals stick out from either side of the front wheel. As you turn the pedals it turns the wheel, so 1 turn of the pedals = 1 turn of the wheel. However much effort it takes to turn the pedals round it will always take you the same distance.


On a 'proper' bike the pedals are connected to the wheel by a chain and two cogs, one on the pedals and one on the wheel. If the two cogs are the same size, then just like the trike, one turn of pedals = one turn of wheel. But if the pedal cog is twice the size of the wheel cog, each turn of the pedals turns the wheel twice, making you travel twice as far. Carrying you and your bike twice as far needs more effort from you, so it feels harder to pedal - this is a higher gear. If the pedal cog is half the size of the wheel cog you only go half as far for each turn of the pedals, so it feels easier - it's a lower gear.


That's it really. The size of cogs is measured by the number of teeth they have, and how high or low gears are is determined by the ratio of teeth between front cog and back cog. The most efficient way to cycle (allegedly) is to try and maintain a steady rate of turning the pedals, so if you feel it getting harder (going up a hill, into the wind, feeling tired) you change to a lower gear, keep pedalling at the same speed, but actually travel a bit slower (each turn of the pedals takes you a shorter distance).


I'm sure there are many others who could explain it better, but it seemed to work with the kids. If you actually want someone to fix your gears I would recommend a chap who posts on here as 'mlteenie' and is both an excellent bike mechanic and an all round good guy.

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Hmm. I get the DaveR explanation, but I still don't know how to switch between the gear thing with three clicks and how that relates to the gear thing with 7 clicks. Do I need to go all way to top of one before changing the click on the three or can you switch when you're in the middle?

See? I can't even explain what it is I don't understand....!

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"Hmm. I get the DaveR explanation, but I still don't know how to switch between the gear thing with three clicks and how that relates to the gear thing with 7 clicks. Do I need to go all way to top of one before changing the click on the three or can you switch when you're in the middle? "


So, people seem to think I did an OK job with the last explanation (thanks guys, I'm touched) so I'll have another go.


I said before that how high or low a gear is is determined by the ratio between the number of teeth on the pedal cog and the number of teeth on the wheel cog. So, a 40/20 ratio means pedal cog is twice the size of wheel cog, one turn of pedals = two turns of the wheel, but 40/10 is four times the size, and so a higher gear. If you have a 40 pedal cog and wheel cogs of 10/20/30/40 you have a simple sequence of four gears from high to low.


But if you have two pedal cogs, 40 and 20, and the same four wheel cogs, you have eight different combinations, but they don't run in a nice sequence from high to low. For example 40/20 and 20/10 are different combinations of cogs but the same ratio, so for practical purposes they are the same gear - number of pedal turns vs wheel turns is the same.


So, the short answer to the specific question is no, you don't need to go all the way to the top, and in fact you're probably OK to ignore the 'three' almost all the time. The three clicks will be the three cogs at the front, that I've called pedal cogs, and the seven are the ones at the back, wheel cogs. If you don't change the front ones at all and just use the rear ones, each time you click to a higher number you will go into a higher gear, if you click to a lower number you will go into a lower gear. With 7 gears the gaps between each one won't be too big so it should be fairly smooth and easy moving up or down by one.


In practice, if you find your optimal everyday gear combination, where you can bowl along at a comfortable pace without feeling like you have to really push hard on the pedals, you probably only want to ever shift up or down one or two clicks. I spend 80% of the time riding on H5 (High gear, or big cog on the front, and number 5 out of 8 on the back), at least when commuting. I shift down to H4 if I can see I'm going to have to stop at a red light, for example (and yes, I do invariably stop) because it makes it easier to start again. I shift up to H6 or occasionally H7 when I'm on the Old Kent Road and some proper space opens up, and it's time to hit the gas. I pretty much only change to the Low front cog going up Dog Kennel Hill.


Obviously you can avoid all the fuss by riding a single speed bike, but you might have to grow a beard and get some tattoos.

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"Or get a car and do away with all this cycling nonsense."


I have a car, and very useful it is too. I'd particularly recommend using a car to go to IKEA, for example (I did it once on public transport, and it clearly wasn't optimal). But the car's no good for commuting from ED into the City - it's no quicker than the bike and parking is ?25/day.

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+ congestion charge. + endless frustration of being stuck. + torturing the engine in 1st/2nd. why anyone would drive into Central London as a commute, after, say 6AM, and before, say, 8PM is beyond me.
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I imagine Salsaboy was just making a little joke.


Cycling seems like pretty much the best way of getting around... but I'm just far too much of a chicken to cycle in London.


The only people I know of who drive into central London for work are either posers with fancy cars, or people needing to start very early / finish very late.

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