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  1. #1
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    Mr Pivot: Why the relaxed seat tube angles?

    Seems like all the Pivot bikes have such relaxed seat tube angles compared to other brands. 73 degrees has always been the sweet spot for this 6' 2" 180lb long torso long armed rider. My XL 429C has a seat tube angle of 71.9 which in order for me to get the correct pedaling position I have to slam the saddle forward, which in turn loses me vital top tube length and forces me into a longer stem than I'd like 110. I still really like the bike, but just think it would be even better with a more neutral ST angle. Does CC cater to supermodels and Kenyans(long femur freaks)?

  2. #2
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    Mr Pivot: Why the relaxed seat tube angles?

    You are using a zero setback seat post correct? Just checking don't flame. Pivot recommends a zero setback.


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  3. #3
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    It's not that simple to design a frame to match every possible size. For example I'm 6' 3" and ride a L-size 429C with a 85mm stem which suits me perfectly. So obiviously there is big variation depending your arm, torso and leg length.

    Also some people like their riding position to be really low and long (XC- style) and some like a more upright position for easier trail riding. :-)

  4. #4
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    Quote Originally Posted by Xizor1 View Post
    It's not that simple to design a frame to match every possible size. For example I'm 6' 3" and ride a L-size 429C with a 85mm stem which suits me perfectly. So obiviously there is big variation depending your arm, torso and leg length.

    Also some people like their riding position to be really low and long (XC- style) and some like a more upright position for easier trail riding. :-)
    Agree. Like the OP, I'm 6'2", long arms and longish torso, and demoed a 429 back in 2012. The bike fit beautifully with the seat in the middle of the range. On most XL bikes I feel cramped and slam the seat back. Admittedly I'm not the norm.

  5. #5
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    Quote Originally Posted by ejreyes6 View Post
    You are using a zero setback seat post correct? Just checking don't flame. Pivot recommends a zero setback.


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    Yep. Thompson straight post.

    Don't get me wrong, I really like the 429Carbon. But I think better geometry would make it even better.

    Here's seat tube angles from other bike makers:

    Specialized 73.75
    Trek. 73.6
    Giant 73
    Niner 73.5
    Cannondale 73.5
    Turner 73
    Pivot 71.9

  6. #6
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    Re: Mr Pivot: Why the relaxed seat tube angles?

    Similar 100mm FS bikes (Anthem, Superfly, Epic,...) have indeed about 73 degree seat angle, but slap in a 120mm fork and you will get roughly the same 72 degrees as 429C.

  7. #7
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    The slack STA works great for me. Puts me in a good pedalling position with a decent TT length for the flats, but keeps the bike wheel base short making it agile when I am standing.
    Safe riding,

    Vik
    www.vikapproved.com

  8. #8
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    Mr Pivot: Why the relaxed seat tube angles?

    Rideon
    Curious what bike you came off
    of.


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  9. #9
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    Quote Originally Posted by Xizor1 View Post
    Similar 100mm FS bikes (Anthem, Superfly, Epic,...) have indeed about 73 degree seat angle, but slap in a 120mm fork and you will get roughly the same 72 degrees as 429C.
    Yep. Makes sense. Then why not design the whole bike with 120mm in mind, considering correct me if I'm wrong, 120mm is the most popular suspension/size?

    My guess is that the carbon mold was set, and they didnt want the expense of redoing it. They had already committed to 100mm. But then all us customers went 120 on the fork preference.

  10. #10
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    Quote Originally Posted by ejreyes6 View Post
    Rideon
    Curious what bike you came off
    of.


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    I've owned Turner Sultan, Turner Czar, Superfly 100, Specialized Epic 100, Superfly HT, Specialized Stumpjumper HT in the last 5 years. All 29ers. Keepers were the Sultan and Superfly HT. I like the 429C better than the Sultan almost in every way, except ST angle, bottle mount location, and I'd say I prefer zircs and bushings over bearings. The 429C is a great bike.

    Had a first gen Mach 5 several years ago. Same issue with the super relaxed ST angle IMHO. One of my favorite bikes of all time was the Titus made Hammerhead 100. This was the first 100mm travel RacerX(26). CC really nailed that one!

  11. #11
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    Slacker STAs are better for trail riding...

    To get proper leg extension the seat needs to be up and/or back. On a steep STA I feel like I'm on top of the bike, perched up high like a canary. Getting proper leg extension with pushing the seat back gives me proper leg extension, without raising the saddle too high, and keeps me "in" the bike, not on top of it.

    Another reason for slacker STAs.... bikes now have shorter stems, so you have a relatively shorter reach to the bars - sometimes too short. A slacker STA pushes you away from the bar to keep your reach more comfortable.

    Another reason... in general, larger wheels, like 29ers, often require longer stays. A slacker STA will help to keep your weight ideally centered between the two wheels.

    Steep STAs and longer stems are for xc and road bikes. I like my trail bike to ride like a trail bike.

    I run all my bikes with a set back post, including my M6. My inseam is over 34". I'm sitting way over the back wheel, and love it. Steep, techie climbs are my thing, and favorite part of riding.

  12. #12
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    It felt weird to me in the beginning as well. To "solve" it I slammed the seat all the way forward and it felt OK. Fast forward 6 months and while cleaning my bike I noticed that my seat had migrated back over time. So I have been riding with the seat all the way back on the rails for who knows how long. It really comes down to what you are used to. Since my seat migration was slow and over time I didn't notice. Feels fine to me now.

    You should set your stem length to your standing position and not seated. Much easier to adapt your pedalling style than you descending style.

  13. #13
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    Quote Originally Posted by Salespunk View Post
    You should set your stem length to your standing position and not seated. Much easier to adapt your pedalling style than you descending style.
    I think this very important. The balance of the bike in the standing or attack position is really important and even more on a bike with downhill emphasis. If you change the STA without keeping the same TT the bike will feel exactly the same but the TT will be shorter; if you keep the same TT the bike will feel different. I think Chris has nailed it in many, many bikes.

    About something else: Salespunk, how is your Nomad behaving so far? Have you tell your first impressions somewhere else?

  14. #14
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    Quote Originally Posted by Rideon View Post
    Yep. Makes sense. Then why not design the whole bike with 120mm in mind, considering correct me if I'm wrong, 120mm is the most popular suspension/size?

    My guess is that the carbon mold was set, and they didnt want the expense of redoing it. They had already committed to 100mm. But then all us customers went 120 on the fork preference.
    The main idea behind this bike might have been that with a 100mm fork and weight weenie parts you will get a really light, stiff and efficient XC- bike. Then on the other hand put in a 120mm fork, dropper post, wide rims etc. and you get a super capable trail- bike.

    In my opinion there is not another bike on the market in the category with the same possibilities...Anthem, Superfly, Epic etc. pale in comparison if you try to make them trail worthy. :-)

  15. #15
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    I'm 6'6" and ride XL 429c with 17deg 90mm stem and 50mm risers. I had an issue with relaxed seat tube angles of new frames, it hurts my knee to sit too far back. I started with the RIP9 RDO, but quickly sold it after knee pain. I then demoed the Santa Cruz LTc but that also was too relaxed. Finally, the 429c allowed me to be far enough forward because the effective seat tube angle is steeper.

    Overall, just looking at the seat tube angles published by manufactures isn't the whole story. Modern FS frames have at least two angles as shown in the pic below. Therefore, manufactures list an "effective" seat tube angle, but that calculation is based on a fixed point in space. The actual effective angle will vary with the height you set your seatpost and the angles shown in the first pic. The second pic proves my point, the RIP9 RDO is listed at a 72.5deg seat tube angle and the Santa Cruz LTc is at 72.6deg. But Angle 1 is much steeper on the RDO, so with 300mm of exposed seatpost, the RDO will be 26mm further back than the LTc. In short, you just have to demo to find out what works for you, or stalk bike shops with a protractor and yard stick.


    Mr Pivot: Why the relaxed seat tube angles?-rip9-rdo-angles.jpg

    Mr Pivot: Why the relaxed seat tube angles?-niner-ltc_comparison.jpg

  16. #16
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    Quote Originally Posted by maindog View Post
    I think this very important. The balance of the bike in the standing or attack position is really important and even more on a bike with downhill emphasis. If you change the STA without keeping the same TT the bike will feel exactly the same but the TT will be shorter; if you keep the same TT the bike will feel different. I think Chris has nailed it in many, many bikes.

    About something else: Salespunk, how is your Nomad behaving so far? Have you tell your first impressions somewhere else?
    Don't want to derail this thread, but I am settling into it now. Took a little while to get the pressures/stem length correct. I have been setting PR's on climbs and top 10's on the descents despite the fact that my fitness is off from too much work travel. Set my first KOM on it today and had the first ride where I didn't feel the need to change anything.

  17. #17
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    Slightly OT, but with the saddle position, most importantly is it not the relationship between your knee and the pedal axle?
    eg. I've always dropped a line from just under my knee cap which should pass straight down through the pedal axle?
    Personally I'd prefer my seat back more, but if I use the method above I've got to have it all the way forward on my Mach 5.7c..
    Am I wrong/right here?

  18. #18
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    I been wondering the same thing and now that somebody brought it up..

    Now in the days of dropper posts it is not only about finding one perfect position for you saddle. My previous bike had even slacker seat post angle that my beloved Firebird. That was one of the reasons I started looking for another frame. I didn't get the most of my dropper post. Slam it down, I really don't care where the saddle is as long as it's out of the way, but after you find the right spot for cruising/technical ride (where mine stays most of the time) and then lift it up for climbing your saddle is way back over the rear axle and that really doesn't make steep climbs any easier.

    If there was one thing I would change in my Firebird that would be a steeper STA. Was little disappointed when saw the new M6 that looks even slacker (never demoed one so this is only speculation). But yeah I know, when taking chain stay length, wheel size, travel and all other aspects in geometry into accaunt phycique has it's limitations.

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