Notices
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.

granny

Old 09-07-06, 05:58 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Jul 2006
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
granny gear

I'm currently running a 48-38-28 up front and am considering trying to get more of a granny gear, possibly 24. Since I'm a noob, I'm wondering if I can simply swap them out, or will I have trouble with the front derailleur, etc.? It's a Marin and I think the crankset is a Suntour


thanks
Bob N is offline  
Old 09-07-06, 06:06 PM
  #2  
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,684
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 191 Post(s)
Liked 109 Times in 48 Posts
Your crank arms are mostly likely 110/74 BCD. You can mount a 26 ring but I'm not so sure about 24...
roadfix is offline  
Old 09-07-06, 06:33 PM
  #3  
Senior Member
 
mechBgon's Avatar
 
Join Date: Jul 2002
Posts: 6,957
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 6 Times in 5 Posts
74mm bolt circles will take a 24. 7075 aluminum is a good material to look for, here's some for example: https://www.cambriabike.com/shopexd.asp?id=11671

Oh, and make sure the chainrings really are removable. Also, you're going to need a crank extractor to do the swap.
mechBgon is offline  
Old 09-07-06, 08:05 PM
  #4  
Year-round cyclist
 
Join Date: Apr 2002
Location: Montréal (Québec)
Posts: 3,023
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
My daughter has a Marin and it's a 4-arm crankset. I can't remember the bolt circle diameter (BCD), but I know it definitely accepts a 24 because that's what I installed. And her Shimano derailleur with indexed Rapidfire shifters works fine with 48-38-24. I don't think a 22 would have worked properly with her derailleur, however.

BTW, if you don't know the BCD, carefully measure the distance between two bolts (centre-centre). Then visit this page from Sheldon Brown to know the BCD. If you look at the second table, you'll see that, for example, if you measure 45.3 mm between two bolts (3rd column), you need a chainring with 64 mm BCD and the smallest you may install is 22.

Last edited by Michel Gagnon; 09-07-06 at 08:11 PM.
Michel Gagnon is offline  
Old 09-07-06, 09:27 PM
  #5  
Junior Member
Thread Starter
 
Join Date: Jul 2006
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
thanks folks, I'll do some more investigating.
Bob N is offline  
Old 09-08-06, 10:04 AM
  #6  
Senior Member
 
Join Date: Oct 2005
Posts: 5,820
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 383 Post(s)
Liked 133 Times in 91 Posts
How much more of a granny gear do you need? With a 28 front, you should be able to use a 24 rear, which gives you almost 1:1 gearing, which is very low. Do you want to go below 1:1?
__________________
Il faut de l'audace, encore de l'audace, toujours de l'audace

1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1
San Rensho is offline  
Old 09-08-06, 12:04 PM
  #7  
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Posts: 27,274

Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones

Mentioned: 150 Post(s)
Tagged: 1 Thread(s)
Quoted: 6147 Post(s)
Liked 4,092 Times in 2,325 Posts
Originally Posted by The Fixer
Your crank arms are mostly likely 110/74 BCD. You can mount a 26 ring but I'm not so sure about 24...
Could also be a 130/74BCD. In either case, a 24 will fit. If it's a 110/74 BCD everything is hunky dory. If it's a 130/74, shifts to the lowest gear with a 24 may get trapped in between the middle ring and the inner ring. In either case, your derailer is just fine
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!



cyccommute is offline  
Old 09-08-06, 12:07 PM
  #8  
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Posts: 27,274

Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones

Mentioned: 150 Post(s)
Tagged: 1 Thread(s)
Quoted: 6147 Post(s)
Liked 4,092 Times in 2,325 Posts
Originally Posted by San Rensho
How much more of a granny gear do you need? With a 28 front, you should be able to use a 24 rear, which gives you almost 1:1 gearing, which is very low. Do you want to go below 1:1?
Go as low as your masculinity will allow Me, I'm a whimp. All my bikes have 22 or 20 with a 34 in the back but then I have these big rocks in my backyard that kinda force me to do that
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!



cyccommute is offline  
Old 09-08-06, 12:10 PM
  #9  
hello
 
roadfix's Avatar
 
Join Date: May 2003
Location: Los Angeles
Posts: 18,684
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 191 Post(s)
Liked 109 Times in 48 Posts
Originally Posted by San Rensho
How much more of a granny gear do you need? With a 28 front, you should be able to use a 24 rear, which gives you almost 1:1 gearing, which is very low. Do you want to go below 1:1?
I'm a whimp too.... I'm running 22/32/44 and a 11-32 cassette on my mountain bike.....
roadfix is offline  
Old 09-08-06, 12:35 PM
  #10  
GATC
 
Join Date: Jul 2006
Location: south Puget Sound
Posts: 8,728
Mentioned: 29 Post(s)
Tagged: 0 Thread(s)
Quoted: 464 Post(s)
Liked 49 Times in 27 Posts
Below 1:1 rules!
HardyWeinberg is offline  
Old 09-08-06, 03:27 PM
  #11  
Senior Member
 
well biked's Avatar
 
Join Date: Jul 2005
Posts: 7,487
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 140 Post(s)
Liked 162 Times in 89 Posts
Definitely sounds like a 110/74 BCD crankset. 24t will work with the 74 BCD, it's the smallest ring you can put on it. I think it will shift fine; it's usually a big jump between the middle and outer ring that can cause difficult front derailleur shifting on a triple, at least that's been my experience...........I run a 46/36/24 setup with my 110/74 BCD cranks on my old commuter/tourer/whatever-else bike, with an 11 x 32 cassette in the rear. A very nice range of gears IMHO-
well biked is offline  
Old 09-08-06, 05:55 PM
  #12  
Junior Member
Thread Starter
 
Join Date: Jul 2006
Posts: 6
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The casette is an 11-32 I believe. I have no idea what less than a 1:1 ratio signifies, light in the loafers?

I have to cross the Potomac on my commute (which I've done twice with panniers, 20 miles each way) and going uphill with a load can tax my noodly legs. I'm not one to pack lightly (for me at least) and I tend to go for distance and carrying capacity over speed.

A wider range of gears seems appealing as my manliness prohibits me from dismounting and pushing the bike up a hill. I have noticed that I 'm getting better on hills, but I've been in situations where I've thought...."man, if this hill were any steeper, I wouldn't make it". I want to be able to do ALL THE HILLS.

pondering it more, thanks for the input again, I really appreciate it
Bob N is offline  
Old 09-08-06, 09:26 PM
  #13  
Year-round cyclist
 
Join Date: Apr 2002
Location: Montréal (Québec)
Posts: 3,023
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
Originally Posted by Bob N
The casette is an 11-32 I believe. I have no idea what less than a 1:1 ratio signifies, light in the loafers?

Right now, you have 48-38-28 in front and 11-32 in the back. Your lowest ratio is 28/32, so it's less than 1:1. If your smallest chainring was a 32, you would have 32 front / 32 rear, or 1:1. The smaller the (front/rear) ratio, the easier it is to pedal.
Michel Gagnon is offline  
Old 09-09-06, 12:40 PM
  #14  
Senior Member
 
Join Date: Oct 2005
Posts: 5,820
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 383 Post(s)
Liked 133 Times in 91 Posts
Originally Posted by cyccommute
Go as low as your masculinity will allow Me, I'm a whimp. All my bikes have 22 or 20 with a 34 in the back but then I have these big rocks in my backyard that kinda force me to do that
Wow, that is low gearing I guess I ride the road most of the time and when I do occassionally ride off road, its flat as a board (Miami, Fl.) so I've never had the need, really. More power to yah
__________________
Il faut de l'audace, encore de l'audace, toujours de l'audace

1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1
San Rensho is offline  

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.