Page 1 of 4 1 2 3 4 LastLast
Results 1 to 25 of 81
  1. #1
    mtbr member
    Reputation:
    Join Date
    Nov 2004
    Posts
    507

    Carbon seatstays - why?

    This from "Ask RC" on the Mountain Bike Action magazine website:

    Q. Hi RC! I've noticed that a lot of mountain bikes are coming out with carbon seat stays. I would like to know what are their disadvantages over aluminum seat stays and if your bike has one, what can we do to protect them from damage. Thanks
    Erwin/mbaction.com - 6/14/2007 3:35:51 PM

    A. RC: I know I will incur some wrath here, but, of all the stupid places to use carbon fiber, the seatstay of a mountain bike is the dumbest yet. Does it save weight? No, not unless the previous aluminum stay was poorly designed. Composites are weakest in compression--exactly what the major stresses are on a seatstay. A paper-thin aluminum stay would do a better job and for less money. Basically, it's the easiest place for a bike maker to put carbon where its customers will see it and say "Wow, that is cool."

    Now I know that many people do not agree with a lot of Richard Cunninghame's ideas BUT I tend to agree with the statement above.
    Not sure why the new ML frame has to have carbon seatstays?
    Purely bling factor?
    Marketing hype following the "carbon is cool" trend?
    Just my 2c
    Goatman
    - It's not the destination that counts but how you get there -

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,381
    I'd tend to agree as well while having a few different opinions. Carbon on the stays is silly but I'd say carbon on the chain stays would be the dumbest yet with seat stays a distant second. I also don't think strength of composite is really that much of an issue on a seat stay but apparently the bonding AL to Carbon is an issue.

    I have a Racer X, not an ML but I would definitely welcome an all AL rear triangle option.
    Titus Racer X
    Lynskey Singlespeed

  3. #3
    on my 3rd wind...
    Reputation: SingleTrackHound's Avatar
    Join Date
    Jul 2003
    Posts
    1,753

    Agree..

    Everyone should inspect the nicks, scratches, & dings on their 1+ yr old aluminum seatstay and chainstay. Imagine if it was made out of a carbon. When I fall, I don't fall pretty, and frame take quite the beating as it rams into the rock and boulder. Carbon bits on frame, I just don't get.
    sth

  4. #4
    the 36 year old grom
    Reputation: demo_slug's Avatar
    Join Date
    Jan 2005
    Posts
    2,726
    I think the best place to use carbon on a bike is almost everywhere…..

    In regards to motive…
    My guess as to why the seat stay is a popular place to add carbon is the cost of the part. Its already a complex weldment and probably “expensive” to begin with. Probably a cost effective place to add a carbon part.

    and on the ML is saves 75g

  5. #5
    MTB aficionado
    Reputation:
    Join Date
    Jan 2004
    Posts
    950

    Replacement seat-stay

    My 2005 AL seat-stay cracked and Titus warranted the part with their new CF one. I was a bit surprised to say the least when I got it since I was expecting the polished AL variety.

    Well, it is rather sexy and I'm more than happy to give it a beating. Granted, I haven't crashed on it yet, but all is well so far. I do worry about that inevitable crash, however. But, I just ride with the assumption that if it fails within a two year period, I'll just get it replaced again at no charge. Or if I crash it hard I can opt for the crash replacement policy.

    I just hope this isn't one of those material uses that are relegated to MTB infamy and puts me in the hospital.... or worse.

    P.S. The CS regarding this matter was excellent and I was taken care of in a very timely manner.

    Regards,

    EndUser
    My advice and $3 will buy you nothing more than a tunafish sandwich.

  6. #6
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    55
    I have a pre-production ML 2. It has the hydro-formed chain stays and carbon rocker, but still has the aluminum seat stays. Out of curiosity I emailed titus to see what the weight difference on the aluminum vs carbon stays is. They said that most of the weight savings on the ML 2 is actually from the hydro-formed chain stays. The carbon seat stays only make up about 55 grams of the difference.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Oct 2006
    Posts
    124
    I have just orderes an ML2 . Should I have gone for the alu version instead???? I might have time to change my order.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Dec 2005
    Posts
    6,212
    Quote Originally Posted by dareverend
    I have just orderes an ML2 . Should I have gone for the alu version instead???? I might have time to change my order.
    no dood

    take your CF one's off

    all take my Alu ones off my bike

    we will swap them over and I will be happy

    i have broke 3 Alu seat or chainstays on 3 different bikes

    Alu rares and their supposed durability are not all their cracked up to be

  9. #9
    Veni Vidi Vici
    Reputation: barelylegal's Avatar
    Join Date
    May 2006
    Posts
    995
    Quote Originally Posted by dareverend
    I have just orderes an ML2 . Should I have gone for the alu version instead???? I might have time to change my order.
    I agree with AM, stick with the ML2 ... Put me next priority if you want to swap... next to AM of course

  10. #10
    mtbr member
    Reputation:
    Join Date
    Oct 2006
    Posts
    124
    thanks fellas.got a bit twitchy when i started reading this thread. can now sleep tonight.

  11. #11
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    Sleep easy, I wanted one when I was at Titus last week, none in stock....

    Sheesh, What about the Scott Ransom Ltd, that is all carbon, no readings on that shiating its pants.....
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  12. #12
    "El Whatever"
    Reputation: Warp's Avatar
    Join Date
    May 2004
    Posts
    18,690
    Quote Originally Posted by Whafe
    Sheesh, What about the Scott Ransom Ltd, that is all carbon, no readings on that shiating its pants.....
    You mean that bike that breaks at the downtube by the BB and uses a leverage ratio of like 4:1???

    No, thank you, sir...
    Check my Site

  13. #13
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    Quote Originally Posted by Warp
    You mean that bike that breaks at the downtube by the BB and uses a leverage ratio of like 4:1???

    No, thank you, sir...
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  14. #14
    thats right living legend
    Reputation: blackagness's Avatar
    Join Date
    Mar 2005
    Posts
    6,378
    Quote Originally Posted by Whafe
    Yeah Whafe you "somehow" picked the exact WRONG bike to hold up as an example of of carbon fiber depenabiliity.

  15. #15
    aus-10 night
    Reputation: germ's Avatar
    Join Date
    Aug 2006
    Posts
    73
    You forget that Titus (and other manufacturers) have been making bikes for quite a while, and they are experts at the process. The image that CF is a weak material is false in so many ways. I bet it would take a hard pounding for those things to break...

    Leave the design and structural integrity problems to Titus...just enjoy what you have!

  16. #16
    the 36 year old grom
    Reputation: demo_slug's Avatar
    Join Date
    Jan 2005
    Posts
    2,726
    ".....Composites are weakest in compression--exactly what the major stresses are on a seatstay...."

    so I wonder what RC says about carbon seat posts. the loading on a seat post is also mostly compression....

  17. #17
    "El Whatever"
    Reputation: Warp's Avatar
    Join Date
    May 2004
    Posts
    18,690
    Quote Originally Posted by demo_slug
    so I wonder what RC says about carbon seat posts. the loading on a seat post is also mostly compression....
    ... only on one side...


    Oddly enough, many hardtails and road bikes have carbon seatstays.
    Check my Site

  18. #18
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    Makes me laugh, when it seems that many think that no companies do any research. Sheesh, when I am on my road bike, which is all carbon at 80kmh downhill, I am not thinking about R Cunningham's comments re carbon being weak as piss etc.... Man alive, the world is full of balloon prickers...

    Go the carbon..................Each to there own though...
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

  19. #19
    what's that rattle?
    Reputation: Blofeld's Avatar
    Join Date
    Jun 2006
    Posts
    321
    Quote Originally Posted by Warp
    Oddly enough, many hardtails and road bikes have carbon seatstays.
    Isn't this done to improve ride quality? Carbon fiber can absorb high frequency vibration very effectively so making the fork and seatstays out of carbon fiber prevents some of this vibration from being transfered to the rider.

    Quote Originally Posted by RC
    Composites are weakest in compression--exactly what the major stresses are on a seatstay. A paper-thin aluminum stay would do a better job and for less money.
    True, single ply carbon fiber is weaker in compression due to microbuckling of the fibers. I would still have to see some cyclic testing results to believe a multi-ply carbon seatstay is weaker than an aluminum seatstay of equivalent weight.

  20. #20
    thats right living legend
    Reputation: blackagness's Avatar
    Join Date
    Mar 2005
    Posts
    6,378
    Quote Originally Posted by Blofeld


    True, single ply carbon fiber is weaker in compression due to microbuckling of the fibers. I would still have to see some cyclic testing results to believe a multi-ply carbon seat stay is weaker than an aluminum seatstay of equivalent weight.

    It is my belief that carbon is indeed stronger than al pound for pound, but isn't the concern more directed towards scratches and nics compromising the integrity of the entire stay in regards to CF.

  21. #21
    "El Whatever"
    Reputation: Warp's Avatar
    Join Date
    May 2004
    Posts
    18,690
    Quote Originally Posted by Blofeld
    Isn't this done to improve ride quality? Carbon fiber can absorb high frequency vibration very effectively so making the fork and seatstays out of carbon fiber prevents some of this vibration from being transfered to the rider.
    Yeah, bro... That was my point. In a HT, the seatstay has to suck up the hits, big or small. On a FS, it "only" pushes the shock.



    Quote Originally Posted by Blofeld
    True, single ply carbon fiber is weaker in compression due to microbuckling of the fibers. I would still have to see some cyclic testing results to believe a multi-ply carbon seatstay is weaker than an aluminum seatstay of equivalent weight.
    Yeah, carbon is much like wood in the sense that it depends how the fibers are laid to provide certain stress characteristics.

    RC may have a point in the sense that weight savings are not huge and that Al is cheaper... but I agree the most with Whafe, to each their own.

    As for me, I worry about impacts. I recently managed to bust a brake lever. Totally my fault. Certainly, there are materials that are not made for cavemen like me. It's something I don't want to worry about.
    Check my Site

  22. #22
    Off the back...
    Reputation: pinkrobe's Avatar
    Join Date
    Jan 2004
    Posts
    1,900
    Quote Originally Posted by Blofeld
    Isn't this done to improve ride quality? Carbon fiber can absorb high frequency vibration very effectively so making the fork and seatstays out of carbon fiber prevents some of this vibration from being transfered to the rider.
    I am of the strong opinion that it's done primarily for marketing purposes, not for ride tuning. Using a traditional 32-spoke wheel instead of a 24-spoke deep rim design will yield a smoother ride than slapping CF seat stays on an aluminum/steel/titanium road frame.

    As to the dis/advantages of using CF on the ML, time will tell.

  23. #23
    what's that rattle?
    Reputation: Blofeld's Avatar
    Join Date
    Jun 2006
    Posts
    321
    Quote Originally Posted by blackagness
    It is my belief that carbon is indeed stronger than al pound for pound, but isn't the concern more directed towards scratches and nics compromising the integrity of the entire stay in regards to CF.
    I think this is the legitimate concern with carbon fiber parts, even if in some circumstances having several distinct layers and fibers will prevent a crack from growing. I guess I didn't read that into RC's reply in the OP.

    Quote Originally Posted by Warp
    Yeah, bro... That was my point. In a HT, the seatstay has to suck up the hits, big or small. On a FS, it "only" pushes the shock.
    Quote Originally Posted by pinkrobe
    Using a traditional 32-spoke wheel instead of a 24-spoke deep rim design will yield a smoother ride than slapping CF seat stays on an aluminum/steel/titanium road frame.
    How much of the spectrum do you think overlaps between the shock, wheels/tires and seatstays in terms of frequencies absorbed?

  24. #24
    the 36 year old grom
    Reputation: demo_slug's Avatar
    Join Date
    Jan 2005
    Posts
    2,726
    Quote Originally Posted by pinkrobe
    I am of the strong opinion that it's done primarily for marketing purposes, not for ride tuning. Using a traditional 32-spoke wheel instead of a 24-spoke deep rim design will yield a smoother ride than slapping CF seat stays on an aluminum/steel/titanium road frame.

    As to the dis/advantages of using CF on the ML, time will tell.
    Time will tell. Nice thing about MTBR is that us consumers get to see/ hear about how all these things break.

    the weak link on the ML has been the aluminum chain stay. they break at the welds.... people been breaking titus seat stays for a long long time, its not just the MotoLite BTW.

    IMHO the whole material argument is silly because this stuff almost always break at a joint. at a weld or a bond. so let the most fatigue resistant joint win!!!

    and firmly disagree that the ML seat stay is "marketing". I have high hopes that they will make the ML stronger and longer lasting.

  25. #25
    "Its All Good"
    Reputation: Whafe's Avatar
    Join Date
    May 2004
    Posts
    10,715
    Quote Originally Posted by pinkrobe
    As to the dis/advantages of using CF on the ML, time will tell.
    Here here, pinkrobe has it totally correct here.....Time will tell!

    I am not having any issues with the carbon moulded into my Ti downtube though.
    The_Lecht_Rocks: whafe - cheeers - may i offer an official apology for the wagon wheeler "dis-belief"

Page 1 of 4 1 2 3 4 LastLast

Posting Permissions

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