Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Swapping chainrings

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.

Swapping chainrings

Old 08-19-12, 03:22 PM
  #1  
Junior Member
Thread Starter
 
Join Date: Aug 2012
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Swapping chainrings

I'm looking to get a specific set of chainring sizes: 24-36-48. I can only find one crankset that comes that way for something like $160.

Looking around the internet it seems you can buy individual sprockets that have a standard BCD, more or less. So how do I assemble a crankset with the chainring sizes I want? Can I start with a triple that has a 48T and replace the other two to be 24 and 36? Is there a standard BCD for the middle and inner sprockets, on those cranks you can replace them on? I'm rather mechanically inclined, and it seems like it should be an easy job. I just don't know what the standards are.

I'm not even sure if it's more expensive this way - I just need 24-36-48 at 170mm on square taper as cheap as I can.
sectrix is offline  
Old 08-19-12, 03:41 PM
  #2  
Senior Member
 
Shimagnolo's Avatar
 
Join Date: May 2008
Location: Zang's Spur, CO
Posts: 9,088
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 3409 Post(s)
Liked 5,594 Times in 2,903 Posts
This is close: https://www.universalcycles.com/shopp...ls.php?id=9824

I put one of these on the ex-GF's bike (before the "ex" part).
I was very impressed with it.

BTW I don't know why they list these as compatible with 6/7/8 speed chains.
I put it on a 9s system where it worked like a charm.

Last edited by Shimagnolo; 08-19-12 at 03:45 PM.
Shimagnolo is offline  
Old 08-19-12, 03:53 PM
  #3  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 13,927

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1815 Post(s)
Liked 1,301 Times in 896 Posts
Typical triples in that range will have 110MM BCD for the 2 larger rings and a 74MM BCD for the granny.

You might try looking for a crank that only requires the large ring to be changed. It "MIGHT" save a few $??
Bill Kapaun is offline  
Old 08-19-12, 05:24 PM
  #4  
Junior Member
Thread Starter
 
Join Date: Aug 2012
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Shim that's funny you post that, because the expensive one I want is the Sugino XD500.

In any case, I found this Alivio M430:
https://www.universalcycles.com/shopp...62&category=62

Which should accept this 24T granny:
https://www.universalcycles.com/shopp...06&category=50

Right? If so, after shopping around that could be less than half the price of the Sugino.
sectrix is offline  
Old 08-20-12, 07:25 AM
  #5  
Thrifty Bill
 
wrk101's Avatar
 
Join Date: Jan 2008
Location: Mountains of Western NC
Posts: 23,542

Bikes: 86 Katakura Silk, 87 Prologue X2, 88 Cimarron LE, 1975 Sekai 4000 Professional, 73 Paramount, plus more

Mentioned: 96 Post(s)
Tagged: 0 Thread(s)
Quoted: 1244 Post(s)
Liked 990 Times in 637 Posts
Originally Posted by sectrix
I'm not even sure if it's more expensive this way - I just need 24-36-48 at 170mm on square taper as cheap as I can.
As cheap as you can = used. I often pick up cranksets like you describe in the form of a used MTB. Last one cost me $20 at a garage sale (for the entire bike of course). Nice Shimano STX components, all of the parts will go onto another MTB frame I am building up for my wife. A lot of used bikes get rarely ridden, so a used crank may be in quite good condition.

Older MTBs can make good donors, the better ones had some pretty decent components. Now the cheap ones with riveted and stamped cranks are junk.
__________________
Please don't confuse ebay "asking" prices with "selling" prices. Many sellers never get their ask price. some are far from it. Value is determined once an item actually SELLS. Its easy enough to check SOLD prices.

Last edited by wrk101; 08-20-12 at 07:29 AM.
wrk101 is offline  
Old 08-20-12, 08:11 AM
  #6  
Senior Member
 
Join Date: Jun 2012
Posts: 354
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
One other thing you need to consider is your front derailleur. Many have limitations with respect to the gap between the gears. For example, the derailleur on my MTB could not handle the gearing you want to use, as it is 2 teeth beyond what it was designed for (it could handle 26/38/48 but not 24/38/48).
TomCat_Ford is offline  
Old 08-20-12, 11:42 AM
  #7  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 13,927

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds. 2019 Giant Explore E+3

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1815 Post(s)
Liked 1,301 Times in 896 Posts
Originally Posted by TomCat_Ford
One other thing you need to consider is your front derailleur. Many have limitations with respect to the gap between the gears. For example, the derailleur on my MTB could not handle the gearing you want to use, as it is 2 teeth beyond what it was designed for (it could handle 26/38/48 but not 24/38/48).
I doubt the FD would notice 2T less on the granny ring.

On my 2 bikes I replaced the large ring on 22-32-44 cranks with a 36 & 38.
Shifting isn't "immaculate", but totally serviceable.
The gap between the large ring & FDER does look awful though.
Bill Kapaun is offline  
Old 08-20-12, 11:56 AM
  #8  
Junior Member
Thread Starter
 
Join Date: Aug 2012
Posts: 7
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by TomCat_Ford
One other thing you need to consider is your front derailleur. Many have limitations with respect to the gap between the gears. For example, the derailleur on my MTB could not handle the gearing you want to use, as it is 2 teeth beyond what it was designed for (it could handle 26/38/48 but not 24/38/48).
Yes, this is something I had to replace anyhow. The one I've got for my 22-32-42 looks like it would fit a 50 - somehow my LBS managed to adjust it to work. In any case I plan on replacing that as well - although I was under the impression that the capacity on the front mech wasn't absolute (I think I read this at Sheldon Brown or maybe Crazy Guy). As long as the chain doesn't rub on the mech, one designed for 22T capacity should work as a 24. Here's a mech I was looking at:
https://www.masherz.com/products/shimano/fdm773.htm

So do these things sound compatible? The Alivio M430 and a replacement 24T granny as noted above, plus some 48T derailleur that has a 22 or 24 tooth capacity?

I will be switching to friction by the way, if that makes any difference. I don't have to worry about indexing and shifter issues between companies. It also means I can put most any components on the bike.

Last edited by sectrix; 08-20-12 at 12:01 PM.
sectrix is offline  
Old 08-20-12, 12:10 PM
  #9  
Member
 
Join Date: Jun 2012
Posts: 27
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I would vouch for those Sugino cranks. I had a Sugino XD-350 (cheaper version), and it was great. If you are on a budget, I would suggest getting that over the XD-600. It is actually more durable with 2 steel chainrings instead of 1 or none. I got it for a pretty good price here: https://www.benscycle.net/index.php?m...oducts_id=8654

There is also a 170mm version for the same price. I loved the crankset before my bike got stolen a few weeks later
jdmz is offline  
Old 08-20-12, 01:36 PM
  #10  
Senior Member
 
Join Date: Jun 2012
Posts: 354
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by sectrix
So do these things sound compatible? The Alivio M430 and a replacement 24T granny as noted above, plus some 48T derailleur that has a 22 or 24 tooth capacity?
I would like to think that if a manufacturer rates a front derailleur as having a 22-tooth capacity, that you should probably stick within those limits. After all, why wouldn't the manufacturer list the derailleur as having a 24-tooth capacity if it could handle it? I'm not saying that what you want to do is not possible, because if very well may be. But there is a reason why the manufacturer has listed the 22-tooth capacity.

I would personally stay within the manufacturer's spec, but that's just me.
TomCat_Ford is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ev0lution
Classic & Vintage
24
04-20-20 01:54 PM
wheels78
Touring
10
09-06-18 10:53 AM
honcho
Bicycle Mechanics
9
08-20-18 09:17 PM
marcpro
Classic & Vintage
4
02-23-12 08:54 PM
iain.dalton
Bicycle Mechanics
5
07-21-10 05:14 PM

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.