Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 26 to 50 of 68
  1. #26
    Plays with tools
    Reputation: customfab's Avatar
    Join Date
    Jun 2008
    Posts
    4,195
    Quote Originally Posted by pvd View Post
    I find that Ritchey, Salsa, and Profile make perfectly good stems**. They cost very little, they are light, and they are strong. Why would you pay more? I see lots of people with $200+ stems that don't fit them but they are stuck with as they've invested so much in. Also, these expensive stems aren't much lighter or stronger. Why do you think this is so important?

    **Provided the steerer clamp faces have been squared on a lathe.
    Try and sell the general cycling public on this and let me know how it pans out for you.

  2. #27
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,798
    Just because people are stupid doesn't mean that I should act that way.

  3. #28
    mtbr member
    Reputation:
    Join Date
    Jan 2008
    Posts
    102
    We spec stems on our AllRoad/Adventure bike with a rise stem. One reason is that if you find yourself getting leaner and more flexible and feel you want to increase your drop, it's a lot easier to do if you're not running a flat stem to start with.

  4. #29
    mtbr member
    Reputation: Eric Malcolm's Avatar
    Join Date
    Dec 2011
    Posts
    447

    Functionality vrs Style

    When I first saw the design and picture, I originally dismissed this bike as an ugly effort from a person who should know better. You know, steep sloping top-tube and riser bar stem as pointed out above. However, Peter is smaller than I am, and I have used various means of reducing the size of a bike visually to look not so big.

    I understand the rationale, and also can see the view of the 'conventional look' that is contemporary. Is Peter's bike marketable? It would probably be an orphan sitting in the back corner of a display in a bike shop. But, he clearly built it for himself, with a spec suitable for his application, and any builder would do this for his client as a one-off, given the brief received. I just wouldn't publish it........critical public and all.

    By the way, there are huge weight savings to be had reducing mass at the head tube by keeping it short. I have done the numbers on a frame that would have needed a 240mm HT to be used to comply with convention. I halved the length to 120mm, steerer stem also halved, which is heavier than the HT and constructed a triangular stem/bar 1 piece that looked much more elegant and saved 300grams in the process, sorry, no picture The seat tube and seat stays were also reduced in length giving an over-all weight of 1750g for a Columbus Zona tubed frame.

    Eric
    If I don't make an attempt, how will I know if it will work?

  5. #30
    mtbr member
    Reputation:
    Join Date
    Dec 2012
    Posts
    51
    Hey Peter, I'm with you on the riser stem. All my customs (one Paul Barkley and two TiCycles, all Softrides) were designed with a riser stem in mind for the very reasons you cited. I might lessen the rise a little bit, but my position is pretty settled after 35 years of saddle time. +10, or even +15, is no affront to my sense of style, but any means.

  6. #31
    Plays with tools
    Reputation: customfab's Avatar
    Join Date
    Jun 2008
    Posts
    4,195
    Quote Originally Posted by briderdt View Post
    Hey Peter, I'm with you on the riser stem. All my customs (one Paul Barkley and two TiCycles, all Softrides) were designed with a riser stem in mind for the very reasons you cited. I might lessen the rise a little bit, but my position is pretty settled after 35 years of saddle time. +10, or even +15, is no affront to my sense of style, but any means.
    10 to 15 is one thing, 25 is another deal.

  7. #32
    Moderator Moderator
    Reputation:
    Join Date
    Jan 2004
    Posts
    3,935

    Pete's not in business

    For what it's worth, I don't have a problem with riser stems, and it might be worth checking to see whether someone is, or isn't actually selling bikes before you criticize them based on marketability. It's fine not to like the look (I don't particularly either) but arguing the point on and on is lame, especially when you're doing so based on false premises.

    OT: PVD, as usual, nice work.

    -Walt

    Quote Originally Posted by customfab View Post
    Try and sell the general cycling public on this and let me know how it pans out for you.
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  8. #33
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,798
    @CustomFab, care to put your frames up for critique? How about the bike setups you are riding?

  9. #34
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    1,631
    I think it looks great.

    It's a road bike for mountain bikers.

    Reminds me a lot of Paul Brodie's personal bike. Paul Brodie

  10. #35
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    737
    For most people a road bike should have a sloping top tube. For a long time the sport clung to level top tubes but right now pretty much all the top of the line road bikes have sloping top tubes.

    Stems are similar. In time sloping stems will become as normal as sloping top tubes. Basically unless you need a super low position a level stem does not make much sense. I expect that eventually the top pros will be on sloping stems in the larger sizes for all the reasons that PVD mentioned plus it lowers the front end of the bike for better aerodynamic profile in the context of a thinner stem for the raised bit vs the big fat head tube. The bikes are also lighter using this approach.

    Great job on the bike BTW.
    Mark Farnsworth, Raleigh, NC
    http://farnsworthbikes.com

  11. #36
    Team Captain
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,190
    Any plans to make a custom stem with integrated headset bearing cap?

  12. #37
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,798
    @ScaryJerry.
    Went through that phase a few years ago. It looks cool, but it's a bad direction to go and is not correct route to go. I strongly recomend not doing it now. The reason is that it tends to trap the bike into one stem or stem/bar situation. Forget about passing the bike on to someone else, a rider will float around various setups as time goes by. During the season you may want low. In the winter you may want high. Best to stick to commercially available parts for ease of change.

    PVD WarBird SS - Pvdwiki
    PVD TIE Advanced X1 - Pvdwiki
    PVD Bird of Prey - Pvdwiki

  13. #38
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,095
    FWIW, I think the the stem looks fine. In fact, I like the look of the whole bike. Screw what all the lemmings think you should have for a stem, that's just stupid.
    15mm is a second-best solution to a problem that was already solved.

  14. #39
    mtbr member
    Reputation: NorseRider's Avatar
    Join Date
    Feb 2004
    Posts
    169
    I like it a lot. Nice work.

    Truls

  15. #40
    Most Delicious
    Reputation: dr.welby's Avatar
    Join Date
    Jan 2004
    Posts
    989
    Quote Originally Posted by pvd View Post
    Simple enough. In engineering we use a little trick we like to call 'a straight line'. An aquantance of mine came up with that a while ago. His name was Pythagoris.http://en.wikipedia.org/wiki/Pythago...gorean_theorem.
    If you're going to be pedantic you could at least spell it right. The Pythagorean theorem is about calculating the sides of right triangles. It doesn't justify your stem choice - you picked the stem rise first and drew a straight line to your steerer tube at that given angle. You're not using the wisdom of the ancients or doing any sort of mathematical optimization here.

    The smaller triangles in the frame make it stiffer geometrically, allowing for smaller diameter tubes to acheive the same desired stiffness.
    Moving the top tube closer to the down tube along the head tube increases the leverage the fork the fork has on the frame. And one could argue that you're adding flex back with the longer stem.

    I don't have a problem with it though, I think the bike is very PVD and fits his style and 'terroir'.
    Last edited by dr.welby; 01-17-2013 at 09:34 AM.

  16. #41
    Most Delicious
    Reputation: dr.welby's Avatar
    Join Date
    Jan 2004
    Posts
    989
    Do you have a print or straight-on photo of the chainstays?

  17. #42
    mtbr member
    Reputation: Jon Edwards's Avatar
    Join Date
    Aug 2004
    Posts
    439
    I'm going to pick up on something a little different from the stem...

    Compact road frames. As in properly compact, not "oh lets drop the TT 1/2" at the seatcluster and call it compact". Why so few of them?

    Other than aesthetics/tradition, I can't see any advantage to a gate of a frame, when you could make it with smaller, lighter, stiffer triangles and then use a nice long , flexy, comfortable seatpost. The only limiting factor I can see is the ability to fit the rear brake in the conventional position and get the fixing bolt in.

    Off the top of my head, I can only think of PVD and English Cycles, Santa Cruz (I have a 2002 Roadster - its lovely) and possibly Giant (original OCR?) who seem to do the job properly.

    I had a chat with a well respected South of England frame builder on the same subject, and his response was "it'll ride like crap". When asked why, "it just will".

    So what am I missing?

    Cheers!

  18. #43
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,798
    Two things:
    1. Being a respected framebuilder has little to do with knowing how to design a good bike.
    2. Most folk in the industry don't even know why top tubes have traditionally been level.

  19. #44
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,095
    Quote Originally Posted by pvd View Post
    2. Most folk in the industry don't even know why top tubes have traditionally been level.
    Why were they?
    15mm is a second-best solution to a problem that was already solved.

  20. #45
    mtbr member
    Reputation:
    Join Date
    Mar 2004
    Posts
    1,631
    Quote Originally Posted by pvd View Post
    @CustomFab, care to put your frames up for critique? How about the bike setups you are riding?
    What happened to CustomFab's response to this?

    deleted?

    Cuts up PVD's bike but won't show is own? Lame.

  21. #46
    Most Delicious
    Reputation: dr.welby's Avatar
    Join Date
    Jan 2004
    Posts
    989
    Quote Originally Posted by Jon Edwards View Post
    Why so few of them?
    Structurally you're generally better off with trusses than cantilevered members. Double the length of the seatpost and you double the weight of the shaft. But you've also doubled the stress so you have to make the seatpost even heavier. You save some weight from the smaller frame, but again the loads on the frame are higher so the shorter tubes might also have to be thicker.

    Given the narrow range of choices in tubing and components (especially at the OEM level) there might be some combinations that save weight - there might be some that don't.

  22. #47
    mtbr member
    Reputation: One Pivot's Avatar
    Join Date
    Nov 2009
    Posts
    4,123
    Quote Originally Posted by dr.welby View Post
    Structurally you're generally better off with trusses than cantilevered members. Double the length of the seatpost and you double the weight of the shaft. But you've also doubled the stress so you have to make the seatpost even heavier. You save some weight from the smaller frame, but again the loads on the frame are higher so the shorter tubes might also have to be thicker.

    Given the narrow range of choices in tubing and components (especially at the OEM level) there might be some combinations that save weight - there might be some that don't.
    Yes... but no. While thats true, theres no such thing as a "compact" seat post... ie, you dont buy a stronger seat post because you have a compact frame with a foot of post showing. The featherweight regular seat posts work just fine in compacts. Also compact frames are light weight.

    Theres lots of traditional full size frames that break at the tt/st point, and lots of compacts that dont. Some of those compacts are lighter too..

  23. #48
    Most Delicious
    Reputation: dr.welby's Avatar
    Join Date
    Jan 2004
    Posts
    989
    Quote Originally Posted by One Pivot View Post
    you dont buy a stronger seat post because you have a compact frame with a foot of post showing
    Actually, you unknowingly do. The manufacturer has adjusted for the longer seat post by making the wall thickness thicker to handle the larger load.

  24. #49
    Randomhead
    Reputation:
    Join Date
    Sep 2008
    Posts
    1,036
    when top tubes were horizontal it was a lot less common to see broken top tubes at the seat cluster

  25. #50
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,798
    When top tubes were horizontal, a road bike weighed 25 lbs.

Page 2 of 3 FirstFirst 1 2 3 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
  •