Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-24-12, 06:46 PM   #1
krobinson103
Senior Member
Thread Starter
 
Join Date: Mar 2012
Location: Incheon, South Korea
Bikes: Nothing amazing... cheap old 21 speed mtb
Posts: 2,837
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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?
krobinson103 is offline   Reply With Quote
Old 05-24-12, 06:49 PM   #2
DiabloScott
It's MY mountain
 
DiabloScott's Avatar
 
Join Date: Sep 2006
Location: Mt.Diablo
Bikes:
Posts: 6,856
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 172 Post(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?
DiabloScott is offline   Reply With Quote
Old 05-24-12, 06:53 PM   #3
ThermionicScott 
Gratuitous glib and snark
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers)
Posts: 13,645
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 226 Post(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
ThermionicScott is offline   Reply With Quote
Old 05-24-12, 07:07 PM   #4
Myosmith
Lover of Old Chrome Moly
 
Myosmith's Avatar
 
Join Date: May 2011
Location: NW Minnesota
Bikes:
Posts: 2,548
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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/
Myosmith is offline   Reply With Quote
Old 05-24-12, 07:22 PM   #5
Al1943
Senior Member
 
Join Date: Feb 2005
Location: Oklahoma
Bikes: Trek 5500, Colnago C-50
Posts: 9,433
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
A 48 X 12 is a big enough gear for most road riding unless you're a pro.
Al1943 is offline   Reply With Quote
Old 05-24-12, 07:36 PM   #6
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Bikes: I never learned to ride a bike. It is my deepest shame.
Posts: 3,769
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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?)
LarDasse74 is offline   Reply With Quote
Old 05-24-12, 09:11 PM   #7
Reynolds 
Passista
 
Reynolds's Avatar
 
Join Date: Jul 2005
Bikes: 1998 Pinarello Asolo, 1992 KHS Montaņa pro, 1980 Raleigh DL-1, IGH Hybrid, IGH Utility
Posts: 5,493
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
42x12 is nearly equal to 53x15. Would you call it a slow gear?
Reynolds is online now   Reply With Quote
Old 05-24-12, 10:52 PM   #8
jyl
Senior Member
 
jyl's Avatar
 
Join Date: Aug 2006
Location: Portland OR
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: 6,954
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 27 Post(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.
jyl is offline   Reply With Quote
Old 05-25-12, 01:19 AM   #9
krobinson103
Senior Member
Thread Starter
 
Join Date: Mar 2012
Location: Incheon, South Korea
Bikes: Nothing amazing... cheap old 21 speed mtb
Posts: 2,837
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)


Thats the bike.

Quote:
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.
Attached Images
File Type: jpg IMG092.jpg (98.0 KB, 84 views)
krobinson103 is offline   Reply With Quote
Old 05-25-12, 02:08 AM   #10
jimc101
Senior Member
 
Join Date: Oct 2007
Location: West Yorkshire, United Kingdom
Bikes:
Posts: 4,816
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(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.
jimc101 is offline   Reply With Quote
Old 05-25-12, 02:13 AM   #11
krobinson103
Senior Member
Thread Starter
 
Join Date: Mar 2012
Location: Incheon, South Korea
Bikes: Nothing amazing... cheap old 21 speed mtb
Posts: 2,837
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
krobinson103 is offline   Reply With Quote
Old 05-25-12, 06:18 AM   #12
hyhuu
Senior Member
 
Join Date: May 2011
Location: NoVA
Bikes: Specialized Allez Sport
Posts: 1,380
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
hyhuu is offline   Reply With Quote
Old 05-25-12, 09:21 AM   #13
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 20,482
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 668 Post(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..
fietsbob is offline   Reply With Quote
Old 05-25-12, 10:21 AM   #14
TurbineBlade
Kid A
 
TurbineBlade's Avatar
 
Join Date: Aug 2009
Location: Alexandria, VA
Bikes:
Posts: 1,778
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
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".
TurbineBlade is offline   Reply With Quote
Old 05-25-12, 10:29 AM   #15
gmt13
Half way there
 
gmt13's Avatar
 
Join Date: May 2011
Location: Durham, NC
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)
Quoted: 0 Post(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
gmt13 is offline   Reply With Quote
Old 05-25-12, 11:51 AM   #16
Reynolds 
Passista
 
Reynolds's Avatar
 
Join Date: Jul 2005
Bikes: 1998 Pinarello Asolo, 1992 KHS Montaņa pro, 1980 Raleigh DL-1, IGH Hybrid, IGH Utility
Posts: 5,493
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(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.
Reynolds is online now   Reply With Quote
Old 05-25-12, 12:10 PM   #17
ultraman6970
Senior Member
 
Join Date: Dec 2005
Bikes:
Posts: 7,860
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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 12:15 PM.
ultraman6970 is offline   Reply With Quote
Old 05-25-12, 03:24 PM   #18
krobinson103
Senior Member
Thread Starter
 
Join Date: Mar 2012
Location: Incheon, South Korea
Bikes: Nothing amazing... cheap old 21 speed mtb
Posts: 2,837
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
krobinson103 is offline   Reply With Quote
Old 05-26-12, 10:37 AM   #19
Bat56
Senior Member
 
Bat56's Avatar
 
Join Date: May 2010
Location: St.Paul, MN
Bikes:
Posts: 1,733
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
"But peddling really fast just to acheive the same result?"

Classic!
Bat56 is offline   Reply With Quote
Old 05-26-12, 01:39 PM   #20
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Bikes:
Posts: 11,606
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
I can get 38mph out of a 42x12t gear...
DannoXYZ is offline   Reply With Quote
Old 05-26-12, 04:19 PM   #21
achoo
Senior Member
 
Join Date: Dec 2009
Bikes:
Posts: 4,700
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
achoo is offline   Reply With Quote
Old 05-26-12, 04:50 PM   #22
Mithrandir
Senior Member
 
Mithrandir's Avatar
 
Join Date: Jun 2011
Location: Buffalo, NY
Bikes: 2012 Surly LHT, 1995 GT Outpost Trail
Posts: 2,400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
Mithrandir is offline   Reply With Quote
Old 05-26-12, 04:59 PM   #23
krobinson103
Senior Member
Thread Starter
 
Join Date: Mar 2012
Location: Incheon, South Korea
Bikes: Nothing amazing... cheap old 21 speed mtb
Posts: 2,837
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
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 05:37 PM.
krobinson103 is offline   Reply With Quote
Old 05-27-12, 06:09 PM   #24
MikeWMass
Senior Member
 
Join Date: May 2012
Location: western Massachusetts (greater Springfield area)
Bikes: Velosolex St. Tropez, LeMond Zurich (spine bike), Rotator swb recumbent, Cignal tandem
Posts: 508
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It would be even worse with small wheels.
MikeWMass is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:48 PM.