Page 1 of 3 1 2 3 LastLast
Results 1 to 25 of 68

Thread: XC Seat Height?

  1. #1
    There's always an angle
    Reputation: Photo Kid's Avatar
    Join Date
    Aug 2009
    Posts
    31

    XC Seat Height?

    I see in most of the photos posted in this forum, most XC seats seam to be at a height much higher than the handlebars. I'm wondering if I am missing something in perfoamnce and / or comfort?

    Is this to maximize your leg reach for more power? Better aerodynamics? It would seem that it would put a lot of weight on your hands? Likewise, how do you get your "sit" bones to hit your saddle properly when leaning over at such an angle?

  2. #2
    Can't feel my legs
    Reputation: JPark's Avatar
    Join Date
    Aug 2009
    Posts
    852
    You are talking about two seperate things. First, seat hight should be adjusted to leave a slight bend to the knees at the bottom of your pedal stroke. This is the standard for most riders. Then, different stem lengths and angles can be used to tune to confort/handling and riding styles. Details on the second part can be found in many threads on this site.

  3. #3
    Formerly of Kent
    Reputation: Le Duke's Avatar
    Join Date
    Mar 2009
    Posts
    2,800
    Quote Originally Posted by JPark
    You are talking about two seperate things. First, seat hight should be adjusted to leave a slight bend to the knees at the bottom of your pedal stroke. This is the standard for most riders. Then, different stem lengths and angles can be used to tune to confort/handling and riding styles. Details on the second part can be found in many threads on this site.
    Yep.

    Seat height, fore/aft positioning and angle have nothing to do with handlebar height/position.

    Get your seat position figured out, so that you can actually produce power on the bike, and go from there.

    I see a lot of "XC" guys who look like they've never pedaled a bike before. Knees pointing outwards, lots of knee bend at the lowest point of the pedal stroke, etc. This is a great reason to buy or borrow a track bike; your inefficient position will be revealed very quickly.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    1,297
    Quote Originally Posted by Le Duke
    Seat height, fore/aft positioning and angle have nothing to do with handlebar height/position.
    I disagree. The relation between the two dictates how bent you need to be at the hips. So if you have a steep seat angle you can tolerate lower handlebars, and vice versa.

    There's no single "correct" saddle or handlebar location, it's all about tradeoffs.

  5. #5
    ups and downs
    Reputation: rockyuphill's Avatar
    Join Date
    Nov 2004
    Posts
    14,050
    Your pelvis should remain mostly vertical so the weight remains on the sit bones, that's a factor of core strength in the ab's. I think this is where some people have issues with numbness in their private parts, if they lack core strength and their pelvis tilts forward so the pelvic bone rests on the front of the seat, there's weight on the nerve. That's also where a lot of lower back pain comes from with the classic XC riding position, if there's insufficient core strength then the lower back muscles try to take up the slack.

    I see some people with their seat so high that their pelvis rocks side to side as well, that's a good indication it's too high.
    I'm a member of NSMBA and IMBA Canada

  6. #6
    There's always an angle
    Reputation: Photo Kid's Avatar
    Join Date
    Aug 2009
    Posts
    31
    Quote Originally Posted by rockyuphill
    Your pelvis should remain mostly vertical so the weight remains on the sit bones, that's a factor of core strength in the ab's. I think this is where some people have issues with numbness in their private parts, if they lack core strength and their pelvis tilts forward so the pelvic bone rests on the front of the seat, there's weight on the nerve. That's also where a lot of lower back pain comes from with the classic XC riding position, if there's insufficient core strength then the lower back muscles try to take up the slack.

    I see some people with their seat so high that their pelvis rocks side to side as well, that's a good indication it's too high.
    That seems rather confusing. It makes sense that I should set my seat up high enough so I have good extension on my legs...but the height of my handle bars would seem to have a direct correlation to the angle I need to set my seat, correct. Otherwise rolling forward takes my sit bones off the seat and puts me on the nose of the saddle. I know the higher I get my seat the more impact it has on numbness in my hands and crotch.

    Any good reference sites on this topic?

  7. #7
    Formerly of Kent
    Reputation: Le Duke's Avatar
    Join Date
    Mar 2009
    Posts
    2,800
    Quote Originally Posted by flargle
    I disagree. The relation between the two dictates how bent you need to be at the hips. So if you have a steep seat angle you can tolerate lower handlebars, and vice versa.

    There's no single "correct" saddle or handlebar location, it's all about tradeoffs.
    Based on the amount of money that professional teams spend on looking into this with all of their riders at the beginning of the season, I have to say that I think you're wrong. There's a reason that Saxobank had a life-size, 3-D model of Dave Zabriskie's TT position made when he was with them, and a reason that they still have it.

    Hell, my team spent several hundred dollars a rider to get us all in powerful, comfortable and efficient positions last year, and that was an amateur team.

    Everything starts from the saddle; stem, bars, etc. can all be adjusted once that is determined. And seat tube angle, in my experience, has relatively little to do with how YOU fit on the bike. There's a reason saddles have long, flat rails, and also a reason for setback seatposts.

  8. #8
    Can't feel my legs
    Reputation: JPark's Avatar
    Join Date
    Aug 2009
    Posts
    852
    As I said in my first post, to me seat height is most important and should be set first. Most XC riders set their seats level to slight foward tilt. A good ergonomic saddle(cut out or similar) should solve most of your issues in the rear area. Ergonomic grips will help for the hands. Further confort can be gained in both areas with stem lenght/angle, but, remember all changes in this area will affect handling and climbing.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jun 2006
    Posts
    637
    Don't know if I can post links to other sites, but there was a good thread on slowtwitch about saddle height by Dr. Coggan: http://forum.slowtwitch.com/gforum.cgi?post=1163166
    96% of greater trochanteric height will allow you to make optimal power and still have enough bend in the knee to hover over the saddle on rough terrain.

  10. #10
    mtbr member
    Reputation: goneskiian's Avatar
    Join Date
    Sep 2004
    Posts
    1,390
    Anybody moderately into racing and training that hasn't had a professional bike fit is missing out big time in a huge part of performance on the bike.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    1,297
    Quote Originally Posted by goneskiian
    Anybody moderately into racing and training that hasn't had a professional bike fit is missing out big time in a huge part of performance on the bike.
    How huge?

  12. #12
    mtbr member
    Reputation: dirthead's Avatar
    Join Date
    Feb 2004
    Posts
    566
    I was professionally fit on my road bike, and setup both my mtb's with the exact same saddle position: height and setback. Road bars are 3" below the saddle, mtb bars about 2" at the bar ends. I think saddle position is the most important to establish first, then adjust stem length for reach, and bar height for comfort or performance.

    Before being fit, my saddle was too low, and my left leg was putting out more power per stroke than my right. After raising the saddle, and attaining a 150 knee angle, my power was equal from side to side, and slightly higher overall.

    Saddle position is extremely important and can affect power and comfort greatly.
    "Confidence is the feeling you have before you fully understand the situation".

  13. #13
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    1,297
    If saddle height were so crucial, it would follow that crank length would also be crucial, yet most "pro" bike fitters seem content with the 2 (maybe 3) sizes available.

  14. #14
    AZ
    AZ is offline
    banned
    Reputation: AZ's Avatar
    Join Date
    Apr 2009
    Posts
    19,996
    Saddle position is the most importent component of correct bike fit. Without correct position you give up huge power , and risk injury to knees and back . Bar height ,stem length etc. are all secondary to saddle position . If you are not able to determine the correct position on your own it is well worth the investment of seeking out proffesional help.

  15. #15
    ups and downs
    Reputation: rockyuphill's Avatar
    Join Date
    Nov 2004
    Posts
    14,050
    Crank length isn't as critical on a MTB compared to a road bike, you'd normally spend a good bit of a MTB race out of the saddle climbing, sprinting, descending etc. unlike a road bike where all those 2.5mm increments might make more of a difference.
    I'm a member of NSMBA and IMBA Canada

  16. #16
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    1,297
    Quote Originally Posted by rockyuphill
    Crank length isn't as critical on a MTB compared to a road bike, you'd normally spend a good bit of a MTB race out of the saddle climbing, sprinting, descending etc. unlike a road bike where all those 2.5mm increments might make more of a difference.
    Which is equivalent to saying that saddle height isn't as crucial.

    Which I kind of agree with, in the sense that on a road bike you spend more time in specific positions than on the mountain bike, and bike handling issues are less important.

  17. #17
    Formerly of Kent
    Reputation: Le Duke's Avatar
    Join Date
    Mar 2009
    Posts
    2,800
    Quote Originally Posted by rockyuphill
    Crank length isn't as critical on a MTB compared to a road bike, you'd normally spend a good bit of a MTB race out of the saddle climbing, sprinting, descending etc. unlike a road bike where all those 2.5mm increments might make more of a difference.
    Yes, but 90% or more of my time every week is spent training for races.

    As such, that means lots of long, seated efforts on the way out to my local trails, or seated efforts while riding up fire roads or trails that are most efficiently climbed while on the saddle, building aerobic power.

    And, let's be honest, there are plenty of people with positions that are off not by 2.5mm, but by 25mm or more, who would most definitely benefit from a professional bike fit. The vast majority of MTBs I see look like they were cobbled together with no thought given to the actual act of riding them; most are a combination of parts thought to suit a certain application (weight, strength, budget), that are slapped on a frame and tightened down without a second thought.

  18. #18
    Formerly of Kent
    Reputation: Le Duke's Avatar
    Join Date
    Mar 2009
    Posts
    2,800
    Quote Originally Posted by flargle
    If saddle height were so crucial, it would follow that crank length would also be crucial, yet most "pro" bike fitters seem content with the 2 (maybe 3) sizes available.
    Generally speaking, most bikes come stock with cranks that are appropriate for a person buying that size of frame, for that application.

    Example: On my road bike, I ride 170mm cranks. Why? I'm 5'6", with legs of very slightly more than normal length. If I switch from my road bike to my track bike, I raise my saddle by 5mm. This is great, because it helps/forces me to spin a higher cadence, smoothly, while clearing the banking on a steep track. And, as a result, I have the same leg extension, and no problems switching between them.

  19. #19
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    1,297
    How do you know that 170 is optimal? Have you tested 165 or 175?

  20. #20
    LMN
    LMN is offline
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    3,510
    Catharine just finished getting fit by the probably the best in the business (Andy Pruitt).

    No big change was made to her bike, the seat height was in the correct range, the bar height was good, the fore-aft was good. That part of the bike fit was good.

    His recommendation were for things that are much harder too change. The big three were
    1. Lower Q-factor.
    2. Wider seat so she sits on her sit-bones.
    3. A bar with more sweep (she already runs a 9 degree sweep bar)

    The interesting thing is he didn't have any fancy technology. He did it the old fasion way.

    If you are getting a fit and some body is charging you a couple of hundered dollars to use their laser fitting system, you are probably spending more than you need too.

  21. #21
    Formerly of Kent
    Reputation: Le Duke's Avatar
    Join Date
    Mar 2009
    Posts
    2,800
    Quote Originally Posted by LMN
    The big three were
    1. Lower Q-factor.
    2. Wider seat so she sits on her sit-bones.
    3. A bar with more sweep (she already runs a 9 degree sweep bar)
    What kind of pedals is she running?

    Who is her saddle sponsor?

  22. #22
    LMN
    LMN is offline
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    3,510
    Quote Originally Posted by Le Duke
    And, let's be honest, there are plenty of people with positions that are off not by 2.5mm, but by 25mm or more, who would most definitely benefit from a professional bike fit. The vast majority of MTBs I see look like they were cobbled together with no thought given to the actual act of riding them; most are a combination of parts thought to suit a certain application (weight, strength, budget), that are slapped on a frame and tightened down without a second thought.
    Are you looking at racers or recreational riders? If you are looking at racers are you looking at Cat 2s and 3s or Cat 1s?

    I think you are basing your opinion here on experience you don't have. You are relatively new to MTB racing. Are you telling me that after a single year of MTB racing you are qualified to critique the fit? MTBing and road racing are different sports.

    The experienced MTB racer has developed a fit for what they think is important to their riding (climbing, descending, cornering, ect...) MTB set-up is all about comprimise, what you comprimise depends on where you ride and your skill set.

    What I think it neat is how every region has a different fit style. The bike set-up that is optimal in Ontario, is not optimal in BC and vice versa.

    Honestly proffesional fitter scare me. I am constantly horrified by the MTB set-up that comes out of professional fitters. Most fitters are roadies who do not understand the demands of MTB racing and the compromises that have to be made.

  23. #23
    LMN
    LMN is offline
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    3,510
    Quote Originally Posted by Le Duke
    What kind of pedals is she running?

    Who is her saddle sponsor?

    Shimano and Selle Italia

  24. #24
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    639
    Quote Originally Posted by LMN
    Catharine just finished getting fit by the probably the best in the business (Andy Pruitt).

    No big change was made to her bike, the seat height was in the correct range, the bar height was good, the fore-aft was good. That part of the bike fit was good.

    His recommendation were for things that are much harder too change. The big three were
    1. Lower Q-factor.
    2. Wider seat so she sits on her sit-bones.
    3. A bar with more sweep (she already runs a 9 degree sweep bar)

    The interesting thing is he didn't have any fancy technology. He did it the old fasion way.

    If you are getting a fit and some body is charging you a couple of hundered dollars to use their laser fitting system, you are probably spending more than you need too.
    That's interesting... Pruitt is one of the pioneers of the "laser fitting systems" as you put it and charges well more than a couple hundred dollars to use such a system in his clinic in Boulder. Did Catharine get her fitting done by Pruitt off-site, or did he just choose not to use all those expensive tools at his disposal?

  25. #25
    LMN
    LMN is offline
    mtbr member
    Reputation:
    Join Date
    Sep 2007
    Posts
    3,510
    Quote Originally Posted by scooter2468
    That's interesting... Pruitt is one of the pioneers of the "laser fitting systems" as you put it and charges well more than a couple hundred dollars to use such a system in his clinic in Boulder. Did Catharine get her fitting done by Pruitt off-site, or did he just choose not to use all those expensive tools at his disposal?
    I wasn't there so can't give all the details.

    My guess is he recognizes that for MTBing a "laser fitting system" isn't practical.

Page 1 of 3 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
  •