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Cycling

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Cycling

Finally got round to getting my (mountain) bike serviced (it's been locked in my mother's garage for the last 7 years) and all seems OK.
I barely used it when I bought it 11 years ago and never really understood the gears.
It has 18 (3 on left and 6 on the right). I understand that lower gears are required for hills and tougher terrain but sometimes changing from say, 8th to 5th seems to be worse going up a hill.
Are there overlaps: e.g. if, say, 7th gear (L1 on left side 1 on right) the same as 6th or something similar?
Maybe I'm trying to over-comlicate something which should be quite simple.
Perhaps one of the regular cyclists here could explain the logic a little bit better for me?

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Re: Cycling

There's usually significant overlaps between the three ranges.
If you want to get technical, count the teeth on all the sprockets (front and back), calculate the ratio for all the combinations and you get an idea.  For example, one gear may have 48 teeth on the front sprocket (chainwheel) and 24 on the back, this gives a rato of 2.0 meaning each time the pedals turn one complete revolution, the back wheel will turn two complete revolutions.  The front changer (3 choices) is a coarse selection and the rear (with 6) is a fine selection.  It is also worth noting that it's best to avoid using those that twist the chain sideways the most (smallest front to smallest rear or largest front to largest rear typically) as the sideways twisting of the chain causes excessive wear and can add to the pedalling effort.
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Re: Cycling

Thanks, walker23.
I knew about gear ratios from old school days but hadn't thought of actually counting the teeth.
What I hate on the left gear changer is it has a range from Lo to Hi with several markers in between. If you don't hit the right spot for the middle set then the chain seems to slip and I have to move the gear changer till I get the right spot. Would have been better if you could only move it to one of three positions.

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Re: Cycling

Unfortunately the only really effective way to deal with the grinding and slipping syndrome is to ease off on the pedaling (but keep them moving steadily with the bike) and gradually make the gearchange until it's positively engaged (and quiet).  Not so easy if you need to change down in a hurry due to a steepening hill though, that comes best with practice - a 'bit like riding a bike really'  Grin
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Re: Cycling

Going slightly off-topic I've always ben a real fan of Sturmey-Archer, you get none of these problems.
3 and 4 speed hubs were adequate for almost anything when I was young (including going over Welsh mountain passes off-road) but then they introduced 5-speed and these days you can get an 8-speed which surely is enough for anyone.  Roll eyes
The other thing I see regularly is cyclists with the seat way too low and/or in the wrong (low) gear, pedalling furiously up a gentle incline or even on the level sitting in a very contorted position.  Grin
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Re: Cycling

Thanks for the tips.
Was most upset when some geezer of around 70 or more passed me without breaking a sweat.
In my defence I was slowing for SWMBO to catch up  Crazy

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pierre_pierre
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Re: Cycling

when I was looking for a bike way back in 2008, I found a good chart, just googles and this fiirst from Cycle Touring Club http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3521
and this fill in chart http://www.sheldonbrown.com/gears/
and this Wiki  http://en.wikipedia.org/wiki/Bicycle_gearing
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Re: Cycling

From my competition cycling days:
The ball of your feet should be in contact with the pedal -not the instep as you see very often-  adjust the saddle height so that with the pedal at lowest point your legs should be almost (but not fully) straight. Thereby maximum effort is being exerted. Unless you really must have your creature comforts don't use a sprung saddle (or frame except front forks) huge amount of your effort will be absorbed by the springing.
As long as you're happy with them use quick release toe clips or the modern locking cycling shoes.
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Re: Cycling

Thanks for the interesting and informative links, pierre.
It seems that for general use I am better off using the gear in the middle range (what I would call 7 to 12 on my 18 speed bike) only using the lower end when climbing uphill.
There doesn't seem to be a real need to use the higher range of gears.
When I first got a multiple-speed bike I was assuming you used the gears somewhat in the same vain as with a car viz starting in low gear and gradually stepping up as speed builds up but tjhis was, obviously, not the way.
I think I am now better equipped to understand its use.

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Re: Cycling

Quote
I've always ben a real fan of Sturmey-Archer

I can see the reason, though if mal-adjusted, they could slip quite badly leaving your legs spinning 'in between gears'.  The main disadvantage of the Sturmey-Archer hub gear is the use of epicyclic gearing which is less efficient (so more peadling effort required to move the bike at the same speed) compared with chain & sprocket gearing.
It's perfectly possible to combine a Sturmey-Archer hub with Derailleur gears and get an even sillier amount of available ratios 3x3x6=54 gears from a 'standard 3 front / 6 rear mountain bike type setup x 3 ratios on the hub.  I prefer my curent setup of 2 front, 7 rear giving around 12 usable ratios with minimal overlap between ranges and 700c x 23 tyres, those mountain bike 'fat knobblies' absorb far more of your effort than any Sturmey-Archer hub and are completely unnecessary for road use (though you do then need to be a lot more careful about potholes).
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Re: Cycling

Many years ago I believe Sturmey Archer used to have a road racing team, their cycles were fitted with their gear hubs.
Didn't Campagnolo (if you can afford them) come up with a click-stop gear levers once upon a time? Their downfall being the very close adjustment necessary to make them work properly!!
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Re: Cycling

Quote from: walker23
It's perfectly possible to combine a Sturmey-Archer hub with Derailleur gears
those mountain bike 'fat knobblies' absorb far more of your effort than any Sturmey-Archer hub and are completely unnecessary for road use

Did you mean combine SA with dual chainwheel? That can have some uses and my dad tried that on one of his (many) bikes.
Totally agree re tyres. Even for off-road use (though not going down mountains at breakneck speed) good "touring" tyres are fine. But they do need to have the right pressure, I used to aim around 90psi but I think modern racing tyres can go about 50% over that.  Shocked
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Re: Cycling

Quote from: Mav
There doesn't seem to be a real need to use the higher range of gears.

The important thing is to find what leg speed (cadence) you're comfortable with and you then change gear to maintain that comfortably.
See: http://en.wikipedia.org/wiki/Cadence_(cycling) and http://en.wikipedia.org/wiki/Bicycle_gearing
And when you run out of gears - walk!  Grin
And another thing I don't like about mountain bikes - they're so heavy!
My first "proper" hand-built bike (when I was maybe 12?) was so light I could lift it off the ground with 1 finger.
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Re: Cycling

Quote from: Petlew
Didn't Campagnolo (if you can afford them) come up with a click-stop gear levers once upon a time? Their downfall being the very close adjustment necessary to make them work properly!!

I've recently taken my old mid-market Claud Butler hybrid out of storage (several years in a barn), and the grip-shift indexing is still spot on - Shimano SIS. It did take some setting up in the first place though!
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Re: Cycling

Quote
And when you run out of gears - walk!

Not if you're going down a steep hill and you run out of gears on your way up the ratios  Cool
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.