FS SS Conversion vs Purpose Built- Mtbr.com
Results 1 to 10 of 10
  1. #1
    mtbr member
    Reputation:
    Join Date
    Oct 2015
    Posts
    450

    FS SS Conversion vs Purpose Built

    I've got a question that I couldn't find an answer to searching through old threads.

    Compared to a purpose build single speed full suspension frame like the Oxide Battleaxe, Kona A, or DMR Bolt, is there a drawback to converting a non-ss frame with a tensioner (other than the weight penalty of adding the tensioner)? In other words, all things being equal, is there anything that makes a dedicated FS-SS frame better for SS than conversion a non-SS frame?

    I'm aware that a tensioner that pulls down can cause less of the chain to wrap around the rear cog, but this can be avoided by using a tensioner that pushes up.

    What I'm really curious about is whether or not there is some negative performance issues while pedaling under suspension load on a non-SS frame using a tensioner. I can't figure this out.

    TIA
    2003 Kona A
    2005 Kona A
    2012 Cannondale Hooligan
    2016 Salsa Deadwood

  2. #2
    WillWorkForTrail
    Reputation: Cotharyus's Avatar
    Join Date
    Jun 2012
    Posts
    4,403
    Without getting (too) technical:

    My biggest concern would be dealing with anti-squat properties and the like. Most suspension designs are made to pedal well (not bob, etc) within a range of certain gears with regards to the angle of chain pull from the front ring to the rear - not referring to lateral deflection, as us SS'ers know the importance of chainline, but rather the vertical angle of the chain between the front ring and the rear cog. Do your homework to make sure you're in the ballpark for your given frame, and I wouldn't think you'd suffer too much ill effect, although I'd still want to be able to lock the rear out when I have to stand up and hammer.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Oct 2015
    Posts
    450
    Quote Originally Posted by Cotharyus View Post
    Without getting (too) technical:

    My biggest concern would be dealing with anti-squat properties and the like. Most suspension designs are made to pedal well (not bob, etc) within a range of certain gears with regards to the angle of chain pull from the front ring to the rear - not referring to lateral deflection, as us SS'ers know the importance of chainline, but rather the vertical angle of the chain between the front ring and the rear cog. Do your homework to make sure you're in the ballpark for your given frame, and I wouldn't think you'd suffer too much ill effect, although I'd still want to be able to lock the rear out when I have to stand up and hammer.
    Thanks for your response.

    Just to make sure I understand you correctly, you're saying that I should be looking for a frame designed to have minimal chain growth over the rear suspension's travel, right? How do I find this out??
    2003 Kona A
    2005 Kona A
    2012 Cannondale Hooligan
    2016 Salsa Deadwood

  4. #4
    WillWorkForTrail
    Reputation: Cotharyus's Avatar
    Join Date
    Jun 2012
    Posts
    4,403
    Quote Originally Posted by buell View Post
    Thanks for your response.

    Just to make sure I understand you correctly, you're saying that I should be looking for a frame designed to have minimal chain growth over the rear suspension's travel, right? How do I find this out??
    Nope, way off. On the contrary, if you're using a tensioner, and you set everything up right, who cares about chain growth. I'm talking about pedal bob in the suspension.

    Maybe read this:
    Linkage Kinematics Basics of Anti-Squat and Pedal Kickback

    It talks a little about gearing in relation to anti-squat.

  5. #5
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,801
    Chainring size affects pedal bob, because it has a direct effect on the tension of the top of the chain. If there is chain growth, a smaller chainring resists it more. For example if you were to compare 44/22 and 32/16, the gear ratio is the same but the latter combination will resist pedal bob more.

    Cog size can also affect how the rear suspension linkage works, because the side view angle is different. However, to achieve the same gear ratio a larger cog would require a larger chainring also, so the difference here is not that big.

    I think regular (geared) frames are more advanced so a SS conversion would result in an overall better bike.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Oct 2015
    Posts
    450
    Quote Originally Posted by Saul Lumikko View Post
    Chainring size affects pedal bob, because it has a direct effect on the tension of the top of the chain. If there is chain growth, a smaller chainring resists it more. For example if you were to compare 44/22 and 32/16, the gear ratio is the same but the latter combination will resist pedal bob more.

    Cog size can also affect how the rear suspension linkage works, because the side view angle is different. However, to achieve the same gear ratio a larger cog would require a larger chainring also, so the difference here is not that big.

    I think regular (geared) frames are more advanced so a SS conversion would result in an overall better bike.
    I just want to make sure that I understand you correctly. Are you saying that a smaller chainring increases pedal bob? Also, that a smaller cog increases pedal bob?

    Thanks.


    Edit: I just read the article that Cotharyus linked and it makes sense now. I got the answer I was looking for. Thank you!
    Last edited by buell; 03-16-2016 at 08:41 PM.
    2003 Kona A
    2005 Kona A
    2012 Cannondale Hooligan
    2016 Salsa Deadwood

  7. #7
    mtbr member
    Reputation: Saul Lumikko's Avatar
    Join Date
    Oct 2012
    Posts
    1,801
    A smaller chainring resists pedal bob better than a larger one.

    Cogs have little if anything to do with it. It's primarily about the chainring size.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    769
    What about the Spec. Epic as a SS?

  9. #9
    mtbr member
    Reputation:
    Join Date
    Oct 2015
    Posts
    450
    Quote Originally Posted by rushman3 View Post
    What about the Spec. Epic as a SS?
    I don't understand your question. Could you reword it?
    2003 Kona A
    2005 Kona A
    2012 Cannondale Hooligan
    2016 Salsa Deadwood

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    769
    Redo: What about the Specialized Epic FS 29er as a Single Speed conversion?

Similar Threads

  1. Is a 27.5+ conversion as good as a purpose built +sized bike?
    By Crankarm in forum 26+/27.5+/29+ Plus Bikes
    Replies: 4
    Last Post: 11-10-2015, 06:05 AM
  2. Would you buy a purpose built 1x10 wide range drivetrain?
    By circlesuponcircles in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 47
    Last Post: 08-10-2014, 06:49 PM
  3. Replies: 1
    Last Post: 07-17-2012, 12:56 AM
  4. Purpose Built Mule
    By Duntov1967 in forum General Discussion
    Replies: 2
    Last Post: 01-21-2012, 05:38 PM
  5. Purpose built shredders.
    By SuspectDevice in forum 27.5
    Replies: 14
    Last Post: 05-08-2011, 08:08 PM

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.