Advertise on Bikeforums.net



User Tag List

Results 1 to 24 of 24
  1. #1
    Senior Member
    Join Date
    Mar 2012
    Location
    Incheon, South Korea
    My Bikes
    Nothing amazing... cheap old 21 speed mtb
    Posts
    2,835
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    42t is so much slower than 48t on the front

    My new beater came with 42 teeth on the largest chain ring. Being used to 48 I have to say its downright slow. The first chance I get its getting switched out. Seriously, what use is 42 by 12 on a bike meant to be used on paths and roads?

  2. #2
    It's MY mountain DiabloScott's Avatar
    Join Date
    Sep 2006
    Location
    Mt.Diablo
    Posts
    5,667
    Mentioned
    10 Post(s)
    Tagged
    0 Thread(s)
    Clearly they under-estimated their target consumer.
    Are you sure this wasn't intended to be installed on some folder bike with 12" wheels?
    http://diabloscott.blogspot.com/

  3. #3
    7-speed doomsday prepper ThermionicScott's Avatar
    Join Date
    Aug 2011
    Location
    CID
    My Bikes
    1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX
    Posts
    8,923
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)
    What in the world is this bike? A 10-speed that's missing the outer ring?

    That said, I did all of Ragbrai last year with nothing higher than a 38/12, due to some technical issues. Learn to spin!
    Quote Originally Posted by chandltp View Post
    There's no such thing as too far.. just lack of time
    RUSA #7498

  4. #4
    Lover of Old Chrome Moly Myosmith's Avatar
    Join Date
    May 2011
    Location
    NW Minnesota
    Posts
    2,544
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    According to Sheldon Brown's gear calculator 42x12 should provide about 24.4 mph at a cadence of 90 rpm on a 26" bike and 25.1 on a 700c. Not lightning fast, but adequate for commuting, trails, fitness, pleasure etc. What kind of bike is this on?

    http://sheldonbrown.com/gears/
    Lead, follow or get out of the way

  5. #5
    Senior Member
    Join Date
    Feb 2005
    Location
    Oklahoma
    My Bikes
    Trek 5500, Colnago C-50
    Posts
    9,201
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    A 48 X 12 is a big enough gear for most road riding unless you're a pro.

  6. #6
    Guest
    Join Date
    Jul 2008
    Location
    Grid Reference, SK
    My Bikes
    I never learned to ride a bike. It is my deepest shame.
    Posts
    3,769
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Manufacturers have struggled forever to figure out what gearing consumers want. I remember those bikes with 42 tooth rings - Shimano Altus or Acera quality hybrids, usually.
    I also remember when you couldn't find a factory-stock mountain bike with a gear smaller than 24/28. And old ten-speeds have a small gear of 42/27 or so... who in the hell did they think was riding these things? I guess in the 70s people didn't ride up hills.

    While you are waiting to swap gears for something more realistic, Learn to spin at a higher RPM. It's not a good way to travel fast but it makes you a more efficient pedaler (peddler?) and is a great cardiovascular workout. Properly set up clip-in pedals and shoes or toe-clips (toke-lips?) will make it much easier (ma, cheezier?)

  7. #7
    Passista Reynolds's Avatar
    Join Date
    Jul 2005
    My Bikes
    1998 Pinarello Asolo, 1992 KHS Montaņa pro, 1980 Raleigh DL-1, IGH Hybrid, IGH Utility
    Posts
    4,640
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    42x12 is nearly equal to 53x15. Would you call it a slow gear?

  8. #8
    johnliu@earthlink.net jyl's Avatar
    Join Date
    Aug 2006
    Location
    Portland OR
    My Bikes
    61 Bianchi Specialissima 71 Peugeot G50 7? P'geot PX10 74 Raleigh GranSport 75 P'geot UO8 78? Raleigh Team Pro 82 P'geot PSV 86 P'geot PX 91 Bridgestone MB0 92 B'stone XO1 97 Rans VRex 92 Cannondale R1000 94 B'stone MB5 97 Vitus 997
    Posts
    4,317
    Mentioned
    58 Post(s)
    Tagged
    0 Thread(s)
    At 100 rpm, 42 x 13 on a 700C bike gives you a 26 mph "fast cruise". Crank it up to 120 rpm and you can sprint at 30 mph. That's adequate for most riding and most riders, outside of a race setting.
    Your signature contains too many lines and must be shortened. You may only have up to 2 line(s). Long text may have been implicitly wrapped, causing it to be

  9. #9
    Senior Member
    Join Date
    Mar 2012
    Location
    Incheon, South Korea
    My Bikes
    Nothing amazing... cheap old 21 speed mtb
    Posts
    2,835
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    IMG092.jpg

    Thats the bike.

    42x12 is nearly equal to 53x15. Would you call it a slow gear?
    Everyone is different. I don't have any problems pushing 48x12 on the flat out to 30-35km/h for as long as 3 hours. But peddling really fast just to acheive the same result? I don't see the point. With my 44x12 on my nice MTB I can get 36-40km/h for the same cadence it took to maintain 32-35km/h on this bike. With the 48x12 on the old beater I could maintain a much higher cruise for less perceived output. I don't like it. Besides, the top speed I could get out of her was 44km/h while I've managed 56km/h on the other bike (much nicer, lighter etc but still...)

    Found a dude with a triple set that includes a 48t ring he will install for me for $20, sadly I didn't carry much cash today so I'll go back ASAP and get him to install it for me. I really don't like the feeling that bike gives me at the moment. Despite the fact its commuter/beater it still has to FEEL good to ride.

  10. #10
    Senior Member
    Join Date
    Oct 2007
    Location
    West Yorkshire, United Kingdom
    Posts
    3,607
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    If you need that much seaptost extended, that bike is way too small for you, would be more concerned with this, and the possibility of the seatpost snapping (got to be pushing around or over the max insertion marker) than having a 42T front.

    Being as it is a MTB design, would not expect it to have anymore than a 42T at the front a well.

  11. #11
    Senior Member
    Join Date
    Mar 2012
    Location
    Incheon, South Korea
    My Bikes
    Nothing amazing... cheap old 21 speed mtb
    Posts
    2,835
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Thats one super long seat post. Theres plenty left in the tube. In the picture it was too high as I was playing with the basket at the back. It sits a little lower than that usually. Its bigger than the previous versio, though still a little small. Doesn't bother me much as it gets used for lower impact riding than my main ride.

  12. #12
    Senior Member
    Join Date
    May 2011
    Location
    NoVA
    My Bikes
    Specialized Allez Sport
    Posts
    1,193
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by krobinson103 View Post


    Everyone is different. I don't have any problems pushing 48x12 on the flat out to 30-35km/h for as long as 3 hours.
    On a MTB with knobby tires, that's impressive. You should get yourself a road bike, you'll be flying.

  13. #13
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,219
    Mentioned
    47 Post(s)
    Tagged
    0 Thread(s)
    the reason the compact crank became the normal spec on mountain bikes

    is higher ground/obstacle clearance, to ride over, like, fallen logs.

    Not everyone does the maneuver , but the manufacturers like the image..

  14. #14
    Kid A TurbineBlade's Avatar
    Join Date
    Aug 2009
    Location
    Alexandria, VA
    Posts
    1,778
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    42t is so much slower than 48t on the front
    This is one of the great mantras of cycling. This is another:

    "Bicycles have two pedals, one for each foot".
    Cyclist, angler and aquarist

  15. #15
    Half way there gmt13's Avatar
    Join Date
    May 2011
    Location
    Durham, NC
    My Bikes
    69 Hercules, 73 Raleigh Sports, 74 Raliegh Competition, 78 Nishiki Professional, 79 Nishiki International, 83 Colnago Super, 83 Viner Junior
    Posts
    1,107
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If all you have is 1 speed, you have to commit to changing gearing to what suits you. Not every gear setup is right for everybody, so I don't understand what sort of advice or opinion you are looking for.

    -G

  16. #16
    Passista Reynolds's Avatar
    Join Date
    Jul 2005
    My Bikes
    1998 Pinarello Asolo, 1992 KHS Montaņa pro, 1980 Raleigh DL-1, IGH Hybrid, IGH Utility
    Posts
    4,640
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by krobinson103 View Post
    Everyone is different. I don't have any problems pushing 48x12 on the flat out to 30-35km/h for as long as 3 hours. But peddling really fast just to acheive the same result? I don't see the point. With my 44x12 on my nice MTB I can get 36-40km/h for the same cadence it took to maintain 32-35km/h on this bike. With the 48x12 on the old beater I could maintain a much higher cruise for less perceived output. I don't like it. Besides, the top speed I could get out of her was 44km/h while I've managed 56km/h on the other bike (much nicer, lighter etc but still...)

    Found a dude with a triple set that includes a 48t ring he will install for me for $20, sadly I didn't carry much cash today so I'll go back ASAP and get him to install it for me. I really don't like the feeling that bike gives me at the moment. Despite the fact its commuter/beater it still has to FEEL good to ride.
    That 2 teeth difference doesn't mean 5-6 km/h at the same cadence. 44x12 @ 90 rpm is 40.7 km/h, 42x12 is 38.8.

  17. #17
    Senior Member
    Join Date
    Dec 2005
    Posts
    7,819
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    +1 on this one. This kid looks like love to grind and ride like in slow motion.

    In the track we used to get over 60 km/h in sprints using 50x15... and over 42 km/h regular pace making and not forcing it, definitely not a slow gear at all. SOme guys like to go in slow motion for some idiotic reason but well, they dont consider that the grinding gears get get them slower and slower with the time.... too much strength developed but no power to move it fast, uses.. like having the gearbox of a toyota corolla in V8 engine.

    Love to see them in the road rocking their hips from size to size too

    Quote Originally Posted by Reynolds View Post
    42x12 is nearly equal to 53x15. Would you call it a slow gear?
    Last edited by ultraman6970; 05-25-12 at 01:15 PM.

  18. #18
    Senior Member
    Join Date
    Mar 2012
    Location
    Incheon, South Korea
    My Bikes
    Nothing amazing... cheap old 21 speed mtb
    Posts
    2,835
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Comfort is comfort. If I was racing - which I have no interest in I'm sure spinning faster would be better. However, I don't race, have no interest in group rides of any sort so I figure its worth riding a bike in what define as comfort. I wasn't really looking for advice, just commenting on how $%$^ awful that 42 feels.

    Its tempting just to leave it on as the gear train while cheap is super smooth and altering it won't help that. It may also be good to have different gear setups to force myself to spin a little every now and then. If I have the option I'll choose a higher gear over a lower.

  19. #19
    Senior Member Bat56's Avatar
    Join Date
    May 2010
    Location
    St.Paul, MN
    Posts
    1,664
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    "But peddling really fast just to acheive the same result?"

    Classic!

  20. #20
    Senior Member DannoXYZ's Avatar
    Join Date
    Jul 2005
    Location
    Saratoga, CA
    Posts
    11,507
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I can get 38mph out of a 42x12t gear...

  21. #21
    Senior Member
    Join Date
    Dec 2009
    Posts
    4,505
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by krobinson103 View Post
    Comfort is comfort. If I was racing - which I have no interest in I'm sure spinning faster would be better. However, I don't race, have no interest in group rides of any sort so I figure its worth riding a bike in what define as comfort. I wasn't really looking for advice, just commenting on how $%$^ awful that 42 feels.

    Its tempting just to leave it on as the gear train while cheap is super smooth and altering it won't help that. It may also be good to have different gear setups to force myself to spin a little every now and then. If I have the option I'll choose a higher gear over a lower.
    If you're worried about how fast you're going, why is your first post about how a 42t chainring making your slower?

    And if you really think mashing away at a slow RPM is "comfortable", expect to hear, umm, quite a bit of skepticism.

  22. #22
    Senior Member Mithrandir's Avatar
    Join Date
    Jun 2011
    Location
    Buffalo, NY
    My Bikes
    2012 Surly LHT, 1995 GT Outpost Trail
    Posts
    2,287
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    My old GT mountain bike had a 42t large ring. It was great for almost all situations except for fast descents. I ended up just getting a road bike for that.

  23. #23
    Senior Member
    Join Date
    Mar 2012
    Location
    Incheon, South Korea
    My Bikes
    Nothing amazing... cheap old 21 speed mtb
    Posts
    2,835
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    And if you really think mashing away at a slow RPM is "comfortable", expect to hear, umm, quite a bit of skepticism.
    Call me odd then because it is. Also speed is important because I have two young children which limits how much time I can spend riding. I also have busy commuting days so I can't spend time crawling along or bike commuting becomes impractical.

    Thus I need to be able to maintain over 30 km/h without too much effort as I end up sweating less and this makes it easier to clean up when I get too work. A larger gear ratio does this. If I spin fast all the time - as I like to do in training rides I end up drenched.

    I switched the gear set over yesterday. Much nicer. The colors on the crank arms don't match anymore, but I don't care about that. Less incentive for someone to steal it.
    Last edited by krobinson103; 05-26-12 at 06:37 PM.

  24. #24
    Senior Member
    Join Date
    May 2012
    Location
    western Massachusetts (greater Springfield area)
    My Bikes
    Velosolex St. Tropez, LeMond Zurich (spine bike), Rotator swb recumbent, Cignal tandem
    Posts
    432
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It would be even worse with small wheels.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •