Gear ratios

Discussion in 'UK and Europe' started by Bob, Aug 19, 2003.

Thread Status:
Not open for further replies.
  1. Bob

    Bob Guest

    Hello, after a bit of a lay off, I decided to upgrade some of my kit and start cycling to work as
    well as going out for evening and weekend rides. When I first got my bike, many years ago, the
    biggest gear was way too big and it's still way too big after not cycling for a year and a half.

    I've probably only got enough money left over from new helmets and clothes etc to change either the
    rear sprocket, or the front chain rings. Which one has the greatest affect on the gear ratio...?

    I think at the moment I'm running on a 55:12 setup, which is way too hard to pedal for anymore than
    100 metres even with the help of a howling gale as a tail wind. What is a common ratio for general
    cycling about...?

    Cheers,

    --
    bob [at] bobarnott [dot] com http://www.bobarnott.com/
    ----------------------------------------------------------------------------
    "Crash programs fail because they are based on theory that, with nine women pregnant, you can get a
    baby in a month."
    -- Wernher von Braun
     
    Tags:


  2. Peter Clinch

    Peter Clinch Guest

    Bob wrote:
    > Hello, after a bit of a lay off, I decided to upgrade some of my kit and start cycling to work as
    > well as going out for evening and weekend rides. When I first got my bike, many years ago, the
    > biggest gear was way too big and it's still way too big after not cycling for a year and a half.
    >
    > I've probably only got enough money left over from new helmets and clothes etc to change either
    > the rear sprocket, or the front chain rings. Which one has the greatest affect on the gear
    > ratio...?
    >
    > I think at the moment I'm running on a 55:12 setup, which is way too hard to pedal for anymore
    > than 100 metres even with the help of a howling gale as a tail wind. What is a common ratio for
    > general cycling about...?
    >
    > Cheers,
    >

    --
    Peter Clinch University of Dundee Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net [email protected]
    http://www.dundee.ac.uk/~pjclinch/
     
  3. Peter Clinch

    Peter Clinch Guest

    Bob wrote:

    > I've probably only got enough money left over from new helmets and clothes etc to change either
    > the rear sprocket, or the front chain rings. Which one has the greatest affect on the gear
    > ratio...?

    Depends what you'd be changing *to*. There's a gear calculator at Kinetics website you can download
    that can do the numbers for you:

    http://www.kinetics-online.co.uk/html/k_gear.html

    > tail wind. What is a common ratio for general cycling about...?

    My middle gear is 42 at the front and the back cogs are 11-34, so I suppose 42:22 or thereabouts is
    what I usually do (to a 26" wheel).

    Pete.
    --
    Peter Clinch University of Dundee Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net [email protected]
    http://www.dundee.ac.uk/~pjclinch/
     
  4. MSeries

    MSeries New Member

    Joined:
    Jul 29, 2003
    Messages:
    121
    Likes Received:
    0
    My road bikes have 53/39 x12-26(in 9) and 52/42/30x14-24 (in 7) I usually find I'm using 39x19 or 39x17 or 39x15 or 52x19 or 52x17 mostly.

    See if you can change your 55 to a 52 or even smaller.
     
  5. Bob

    Bob Guest

    MSeries wrote:

    > My road bikes have 53/39 x12-26(in 9) and 52/42/30x14-24 (in 7) I usually find I'm using 39x19 or
    > 39x17 or 39x15 or 52x19 or 52x17 mostly.
    >
    > See if you can change your 55 to a 52 or even smaller.

    I was thinking about getting a Shimano 105 FC5502 double chainset -
    http://makeashorterlink.com/?I295322A5

    But the cost of one of those at £89, is far more than say £30 on a new rear cassette. That's why I
    was wondering which one would make the biggest difference. I'd be quite happy to buy either or, but
    I could get other things if I got the cheaper rear cassette.

    Cheers,

    --
    bob [at] bobarnott [dot] com http://www.bobarnott.com/
    ----------------------------------------------------------------------------
    "Crash programs fail because they are based on theory that, with nine women pregnant, you can get a
    baby in a month."
    -- Wernher von Braun
     
  6. Anonymous

    Anonymous Guest

    "Bob" <[email protected]> wrote in message news:[email protected]...
    > MSeries wrote:
    >
    > > My road bikes have 53/39 x12-26(in 9) and 52/42/30x14-24 (in 7) I usually find I'm using 39x19
    > > or 39x17 or 39x15 or 52x19 or 52x17 mostly.
    > >
    > > See if you can change your 55 to a 52 or even smaller.
    >
    > I was thinking about getting a Shimano 105 FC5502 double chainset -
    > http://makeashorterlink.com/?I295322A5
    >
    > But the cost of one of those at £89, is far more than say £30 on a new
    rear
    > cassette. That's why I was wondering which one would make the biggest difference. I'd be quite
    > happy to buy either or, but I could get other things if I got the cheaper rear cassette.

    Can you just replace the offending chainring? Much cheaper.

    (what setup do you have for the front derailleur (assuming you have one...)?)

    cheers, clive
     
  7. Bob

    Bob Guest

    Clive George wrote:

    [snipped...]

    > Can you just replace the offending chainring? Much cheaper.

    Possibly, I'd have to check. Knowing my luck the LBS wouldn't do a replacement that would fit...

    > (what setup do you have for the front derailleur (assuming you have one...)?)

    The bike's got Shimano 105 bits all over, except for the front chain rings, which I haven't a
    clue who made.

    Cheers,

    --
    bob [at] bobarnott [dot] com http://www.bobarnott.com/
    ----------------------------------------------------------------------------
    "Crash programs fail because they are based on theory that, with nine women pregnant, you can get a
    baby in a month."
    -- Wernher von Braun
     
  8. MSeries

    MSeries New Member

    Joined:
    Jul 29, 2003
    Messages:
    121
    Likes Received:
    0
    You might consider eBay, many folk sell slightly used and unused kit on there. I got some 105 Brake Calipers for £17 less than a LBS and £12 less than Parkers. They were unused, unboxed no instructions, maybe last years model, who cares ?

    If you have a Shimano chainset now chances are it will be 130mm PCD [1] and rings are easliy obtained for this sze.

    I may have a used Shimano 600 (~1992) double chainset with 53/39 rings for sale soon, depending on what I decide to do with my stable of bikes. It is currently not fitted to any bike and is technically spare. I thought I might put it back on now that I have finished the big Cols but I got to like the triple so I may keep it and hence the old double is 'spare'. It is well used hence will be cheap but perfectly servicable for a good few thousand miles yet. I have a very old (1989) 105 'blue' double with 52/42 biopace rings, I think. It is very messy, make me an offer if you want to try it.

    Leave a message here if you are interested.

    [1]The diameter of the retaining bolt circle.
     
  9. Graham

    Graham Guest

    "Bob" <[email protected]> wrote in message news:[email protected]...
    > Clive George wrote:
    >
    > [snipped...]
    >
    > > Can you just replace the offending chainring? Much cheaper.
    >
    > Possibly, I'd have to check. Knowing my luck the LBS wouldn't do a replacement that would fit...
    >
    > > (what setup do you have for the front derailleur (assuming you have one...)?)
    >
    > The bike's got Shimano 105 bits all over, except for the front chain
    rings,
    > which I haven't a clue who made.
    >
    > Cheers,
    >
    > --
    > bob [at] bobarnott [dot] com
    http://www.bobarnott.com/
    > --------------------------------------------------------------------------
    --
    > "Crash programs fail because they are based on theory that, with nine women pregnant, you can get
    > a baby in a month."
    > -- Wernher von
    Braun
    >

    I personally use a 50x38 set up at the front with a 9 speed 13-21 0r 13-23 at the back. If you
    are looking to just change the chainrings then TA do a huge selection and can be bought at most
    bike shops.

    Graham
     
  10. Anonymous

    Anonymous Guest

    "Bob" <[email protected]> wrote in message news:[email protected]...
    > Clive George wrote:
    >
    > [snipped...]
    >
    > > Can you just replace the offending chainring? Much cheaper.
    >
    > Possibly, I'd have to check. Knowing my luck the LBS wouldn't do a replacement that would fit...

    A decent one should. Check the recent posts on mail order shops. (Settle has plenty of the
    common sizes).

    Presumably it's got 5 arms. Your next step is to find out the bolt circle diameter. The hard way is
    to try and imagine the circle and measure it. The easy way is to measure the distance between two of
    the bolds and look it up in a table.

    http://www.sheldonbrown.com/gloss_bo-z.html#bcd

    Knowing the BCD (what is it?) you can then buy an appropriate ring.

    cheers, clive
     
  11. Chris French

    Chris French Guest

    In message <[email protected]>, Bob <[email protected]> writes
    >Clive George wrote:
    >
    >[snipped...]
    >
    >> Can you just replace the offending chainring? Much cheaper.
    >
    >Possibly, I'd have to check. Knowing my luck the LBS wouldn't do a replacement that would fit...
    >
    >> (what setup do you have for the front derailleur (assuming you have one...)?)
    >
    >The bike's got Shimano 105 bits all over, except for the front chain rings, which I haven't a clue
    >who made.

    If the rings are removable then it's almost certain that the rings can be replaced, even if your LBS
    doesn't stock that size - though most are one of a few sizes.

    --
    Chris French, Leeds
     
  12. In message <[email protected]>, Bob <[email protected]> writes
    >Hello, after a bit of a lay off, I decided to upgrade some of my kit and start cycling to work as
    >well as going out for evening and weekend rides. When I first got my bike, many years ago, the
    >biggest gear was way too big and it's still way too big after not cycling for a year and a half.
    >
    >I've probably only got enough money left over from new helmets and clothes etc to change either the
    >rear sprocket, or the front chain rings. Which one has the greatest affect on the gear ratio...?
    >
    >I think at the moment I'm running on a 55:12 setup, which is way too hard to pedal for anymore than
    >100 metres even with the help of a howling gale as a tail wind. What is a common ratio for general
    >cycling about...?
    >
    >Cheers,
    >

    What other gears do you have? Do you have a front double or triple? Most racers seem to come with
    53/39 on front and something like 12/25 cassettes. Your 55 is certainly a bit big. But does it
    really matter? How often does anyone really use the very top gear for general cycling?

    If you're looking for lower gears it sounds like changing the front set is the best bet and, if
    you're doing that, fitting a 52/42/30 triple would solve all problems in one go. (But I'm not a
    cycle mechanic so I wouldn't know what expense that would entail).
    --
    Michael MacClancy

    www.macclancy.demon.co.uk
     
  13. MSeries

    MSeries New Member

    Joined:
    Jul 29, 2003
    Messages:
    121
    Likes Received:
    0
    SJS do a Ofmega Vantage Triple for £40, its OK, not very flash but works. Has 50/40/30 rings as standard but is 130mm PCD so Shimano type rings fit. May need a longer BB, I didn't though. This unit worked well for me whilst cycling but go damaged in transit on my way to France.
     
  14. Frank X

    Frank X Guest

    "Bob" <[email protected]> wrote in message news:[email protected]...
    > MSeries wrote:
    >
    > > My road bikes have 53/39 x12-26(in 9) and 52/42/30x14-24 (in 7) I usually find I'm using 39x19
    > > or 39x17 or 39x15 or 52x19 or 52x17 mostly.
    > >
    > > See if you can change your 55 to a 52 or even smaller.
    >
    > I was thinking about getting a Shimano 105 FC5502 double chainset -
    > http://makeashorterlink.com/?I295322A5
    >
    > But the cost of one of those at £89, is far more than say £30 on a new
    rear
    > cassette. That's why I was wondering which one would make the biggest difference. I'd be quite
    > happy to buy either or, but I could get other things if I got the cheaper rear cassette.
    >

    Well 55 -> 50 is going to make 10% difference. So to get a similar change from your cassette you
    would need to go 12->13.2 (or 13 as we need whole numbers)

    at the other end of the cassette (you didn't specify) an example could be 25 -> 27.5 (eg 27 or 28)

    I would just change the cassette, unless you have some particular reason not to.
     
  15. Pete Whelan

    Pete Whelan Guest

    Frank X wrote:
    > "Bob" <[email protected]> wrote in message news:[email protected]...
    >
    >>MSeries wrote:
    >>
    >>
    >>>My road bikes have 53/39 x12-26(in 9) and 52/42/30x14-24 (in 7) I usually find I'm using 39x19 or
    >>>39x17 or 39x15 or 52x19 or 52x17 mostly.
    >>>
    >>>See if you can change your 55 to a 52 or even smaller.
    >>
    >>I was thinking about getting a Shimano 105 FC5502 double chainset -
    >>http://makeashorterlink.com/?I295322A5
    >>
    >>But the cost of one of those at £89, is far more than say £30 on a new
    >
    > rear
    >
    >>cassette. That's why I was wondering which one would make the biggest difference. I'd be quite
    >>happy to buy either or, but I could get other things if I got the cheaper rear cassette.
    >>
    >
    >
    > Well 55 -> 50 is going to make 10% difference. So to get a similar change from your cassette you
    > would need to go 12->13.2 (or 13 as we need whole numbers)
    >
    > at the other end of the cassette (you didn't specify) an example could be 25 -> 27.5 (eg 27 or 28)
    >
    > I would just change the cassette, unless you have some particular reason not to.

    the jump between gears is smaller if you reduce the chainring and keep the rear the same, otherwise
    you will end up with the same widely spaced gear ratios with the 55 and changing the rear cogs

    --
    Pete

    interchange 12 for 21 to reply
     
  16. Pete Biggs

    Pete Biggs Guest

    Bob wrote:
    > Hello, after a bit of a lay off, I decided to upgrade some of my kit and start cycling to work as
    > well as going out for evening and weekend rides. When I first got my bike, many years ago, the
    > biggest gear was way too big and it's still way too big after not cycling for a year and a half.
    >
    > I've probably only got enough money left over from new helmets and clothes etc to change either
    > the rear sprocket, or the front chain rings. Which one has the greatest affect on the gear
    > ratio...?

    Small differences in rear sprockets have more effect than small differences in chainrings, but......

    > I think at the moment I'm running on a 55:12 setup, which is way too hard to pedal for anymore
    > than 100 metres even with the help of a howling gale as a tail wind. What is a common ratio for
    > general cycling about...?

    55 is very unusual. It'll certainly be worth changing that for a smaller one. I suggest 52 or
    smaller for the outer ring.

    More informtation is needed to make more suggestions. Please check and tell us what all the ratios
    are: How many rings in the front and how many teeth do each have? What cassette/freewheel (rear
    sprockets)? What is the smallest and largest cog, and how many cogs? You can physicically count the
    teeth if you don't know.

    This gear calculator is handy for making comparisons (gear inch units are best for this):
    http://www.sheldonbrown.com/gears/

    ~PB
     
  17. Sky Fly

    Sky Fly Guest

    "Bob" <[email protected]> wrote in message news:[email protected]...

    <snip>

    I've often wondered about the different gears that are out there in the market. I know that
    different riders will want different gearing, but I can't help feeling there must be a demand for a
    9 speed cluster that has such a range that you only need one chainring up front. Something like
    11-13-16-19-23- 27-32-38-44 with a ring up front of 42 would would give you a range of gearing to be
    found on most average bikes, and the single ring would simplify the chain transmission system, yes?

    --
    Akin

    aknak at aksoto dot idps dot co dot uk
     
  18. Pete Biggs

    Pete Biggs Guest

    Sky Fly wrote:
    > I've often wondered about the different gears that are out there in the market. I know that
    > different riders will want different gearing, but I can't help feeling there must be a demand
    > for a 9 speed cluster that has such a range that you only need one chainring up front. Something
    > like 11-13-16-19-23- 27-32-38-44 with a ring up front of 42 would would give you a range of
    > gearing to be found on most average bikes, and the single ring would simplify the chain
    > transmission system, yes?

    Perhaps some people might be happy with that but I would find those large jumps between gears
    grossly inefficient and unpleasant. I'm not sure any rear derailleur could cope with such large
    sprockets in any case.

    Problem: chain is more likely to come off when no front derailleur is used with 9-speed systems. The
    chainline would also be less than ideal for the extreme gears.

    I agree that more derailleur bikes should come with single chainrings - they're at lest useful for
    flat areas, but double and triple chainsets exist for good reasons.

    There are "megarange" cassettes which comprise an ordinary collection of sprockets with one jumbo
    one at the end. ...Would be great at least if riding on mostly flat roads but lived at the top of a
    steep hill!

    ~PB
     
  19. Bob

    Bob Guest

    Pete Biggs muttered:

    [snipped...]

    > 55 is very unusual. It'll certainly be worth changing that for a smaller one. I suggest 52 or
    > smaller for the outer ring.

    I was quite surprised when I found out that it was 55 as I'd just watched a time trial on the tely
    and one of the pros was running 55:11. I think at that point I realsied I should have paid more
    attention in the shop...

    > More informtation is needed to make more suggestions. Please check and tell us what all the ratios
    > are: How many rings in the front and how many teeth do each have? What cassette/freewheel (rear
    > sprockets)? What is the smallest and largest cog, and how many cogs? You can physicically count
    > the teeth if you don't know.

    I got down on my hands and knees this morning and counted the teeth on the rear cassette, it's a
    12-22, 8 speed, dunno the make as it's caked in crap and really needs a good glean (which I shall be
    doing this evening). There are two front chainrings which I've managed to get off, with the help of
    copious quantities of WD40 and the biggest screw driver I own. The outside ring is a 55, while the
    inside ring is a 44.

    > This gear calculator is handy for making comparisons (gear inch units are best for this):
    > http://www.sheldonbrown.com/gears/

    He only goes down to 650c x 23mm, I'm currently running 650c x 20mm road wheels. I don't know how
    much of a difference that'll make, but since I switched back to 20mm Continental Grand Prix tyres
    from 23mm Michelin slick tyres, the bike handles so much better.

    Cheers,

    --
    bob [at] bobarnott [dot] com http://www.bobarnott.com/
    ----------------------------------------------------------------------------
    "Crash programs fail because they are based on theory that, with nine women pregnant, you can get a
    baby in a month."
    -- Wernher von Braun
     
  20. MSeries

    MSeries New Member

    Joined:
    Jul 29, 2003
    Messages:
    121
    Likes Received:
    0
    If you switch your chainrings to 52/42 or 52/39 or maybe 53 instead of the 52 you will have a much more 'standard' configuration and will almost certainly find pedalling easier. Your cassette/freewheel is in the standard range.

    Maybe cheaper to replace the chainset than buy new rings depending on what level of quality (weight) you desire. Watch for the fitting on the Bottom Bracket if you do this. You'd need a 'crank puller' for this job as well as a socket set/ big spanner. Modern high end Shimano have splined BBs whereas older kit has a square taper. They two are not compatible and a new BB would also be required. Changing a BB is not always an easy DIY job, especially on old frames, without the correct tools.
     
Loading...
Thread Status:
Not open for further replies.
Loading...