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  1. #1
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    XL Pivot Mach 429c/sl racers-is seat tube angle too slack to pedal efficiently?

    After experiencing a second breakage on my Niner Jet 9 RDO frame, I'm looking at a new frame and the Mach 429sl is at the top of the list. I like to do multi day stage races (Breck, Transrockies, BC Bike Race), and my only concern is the slack seat tube angle on the Pivot. As a tall rider with a 36" inseam, I have a lot of seatpost out, which will move me further back on the bike, and potentially put me in a position where I'm pedalling from behind the crank instead of over top of it.

    Can anyone comment or provide feedback about this? Pivots are not very popular in my area, so the chances of finding an XL to actually demo or even throw a leg over are very slim.
    Thanks

  2. #2
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    I am in a similar position. 36 inch inseam. I ride an XL with a Zero setback thomson. No issues at all.


    Where do you live?

  3. #3
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    I'm near Banff in Canada. The Tallboy is the bike of choice around here, but after owning one, I was never thrilled about it's pedalling performance and general raceability.

  4. #4
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    Quote Originally Posted by slipstream View Post
    After experiencing a second breakage on my Niner Jet 9 RDO frame, I'm looking at a new frame and the Mach 429sl is at the top of the list. I like to do multi day stage races (Breck, Transrockies, BC Bike Race), and my only concern is the slack seat tube angle on the Pivot. As a tall rider with a 36" inseam, I have a lot of seatpost out, which will move me further back on the bike, and potentially put me in a position where I'm pedalling from behind the crank instead of over top of it.

    Can anyone comment or provide feedback about this? Pivots are not very popular in my area, so the chances of finding an XL to actually demo or even throw a leg over are very slim.
    Thanks
    Drop a plumb line off of the nose of your saddle on your current setup, and measure the distance rearward from the center of the bottom bracket to your plumb line. This is know as "saddle setback'. Email Pivot and ask if it's possible that they can replicate your measurements. I bet they'll be happy to try.

    Personally, I have the opposite issue. I have quite long femurs, so I look for slack seat angles. Both Knolly and Turner measured out the above scenario for me, so i don't see why pivot wouldn't.
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  5. #5
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    Thanks, I will measure that up tonight and email Pivot. I was really interested in the Czar but I pretty sure the seat tube would be too short for me on the XL, and the white elephant of the XXL doesn't look like it is ever going to appear.

  6. #6
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    Quote Originally Posted by slipstream View Post
    Thanks, I will measure that up tonight and email Pivot. I was really interested in the Czar but I pretty sure the seat tube would be too short for me on the XL, and the white elephant of the XXL doesn't look like it is ever going to appear.
    I waited a year and a half on the xxl czar before deciding to go ahead with the 429 sl. Great Looking bike, but my money was saved and didn't want to keep waiting. DT is the man though.

  7. #7
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    I ended up going with an XL Mach 429 sl and have ridden and raced it for a couple of months now. The frame is incredibly stiff, great for bigger riders, and mated the frame with a 120 mm Pike RCT3 on the front end, and IMO its a perfect match of stiffness, along with a set of carbon rims, it definitely descends outside of its class as a XC bike. I find with a lot of seatpost out, however, that the relaxed seat tube angle makes it a long reach to the bars even with the seat slammed forward on the rails. I'm hoping my back adapts to more crouched over position over time, but I definitely feel sore after longer rides and races. This is my first DW bike, and I am very impressed. I've ridden most types of suspension through the various bikes I have owned over the years, and I find that the DW link climbs through technical terrain very well. I do use the climb switch on 429 for extended fireroad sections. The Jet 9 RDO is also a very good pedaling bike, more similar to the DW than VPP, but definitely more active, and nowhere near as stiff, and I had had enough with the warranty and reliability issues of Niner. There has been a lot of attention paid to the details on the 429sl, like cable routing, pivots, rubberized downtube and chainstay etc. which seem to be part of the design process rather than an afterthought. Just thought I would share my 2 cents to aid prospective riders, I certainly appreciated honest reviews on the forums when bike shopping to help guide an expensive purchase decision.

  8. #8
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    What size stem do you have? I chose an FSA 70mm stem over the stock 90mm one that came with the bike. Love it.

  9. #9
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    I'm 6'1" with a 36" inseam and went with a large. Just wondering, how tall are you?

  10. #10
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    I started with 100mm stem that I had one my Niner, dropped to an 80mm, and now down to 70mm Raceface Turbine steam with a 740mm bar. My next option is to try a narrower bar, maybe a 720, but I'm diggin' the wider bars now that I've been riding them for a couple of months. I'm 6'4", with a 36" inseam. When buying bikes, I usually have to shop by seat tube length, I need a minimum of a 21.5" frame w/ a 400 mm seatpost to get enough insertion into the frame, and even with that, I don't have much seatpost left in the frame.

  11. #11
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    Bike fit 101.

    Assuming you like the fit on you current bike, measure your seat height and setback on it. When you get a new bike, set the seat up in exactly the same place in relation to the bottom bracket... that doesn't mean clamp it in the same spot on the rails, it means that if you closed your eyes and got on both bikes, the saddle position would feel identical between the two. Then, based on the stack and reach of your new frame versus your old frame, pick a stem size and orientation that puts the bars in the same place in relation to your ass.
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  12. #12
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    @slipstream : i am as tall as you, and I am also hesitating to buy the pivot 429 due to the seat post angle.
    After a few month with the Pivot,now up you recommend a tall guy like me to go on it ?

    Ps : sorry for my poor English... I am French

  13. #13
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    It's definitely taken some position adjustment, but it is a phenomenal bike in many regards. I've slammed the seat forward, which seems to negate most of the slacker seat angle. I've had to shorten the stem because the cockpit is longer, and I'm also trying a slightly wider bar as well. It's been in a quite a few races, and many long rides, and I have adapted to the slightly different body position from my previous bike. The only other bike I would really consider is the XXL Czar which is now available, but can't comment on the sizing. It looks like it has a more traditional seat angle (73ish degrees) and a slightly shorter top tube, and a slight taller headtube, so the cockpit will be slightly more compact. If you can test ride one, that is always the best option (it's never been an option for me...) Aesthetically, the XL Pivot's headtube/downtube/top tube junction should have been made to look like the smaller sizes which look very organic. The XL reminds me of an old Specialized aluminum Epic...

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