Advertise on Bikeforums.net



User Tag List

Results 1 to 12 of 12
  1. #1
    barth-karl
    Guest

    touring with a MTB frame, how ought I size it.....

    Not that I am operating out a modern assumptions of knowable truths, or a belief in a platonic form of bike size.

    Just wondering what the popular theories are - do you use an MTB frame with measurements close to that of your road frame?

    Many MTBs seem to have sloping DTs- would this mean finding a much larger than normal road sized frame?

    Do you say 'screw it' and just use taller seat posts...?

    Interested in your thoughts

  2. #2
    Senior Member robow's Avatar
    Join Date
    Aug 2005
    Posts
    1,889
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Most people will ride a mountain bike which is sized smaller than their road bike. Such as in inches, my road bike is 22" and my mountain bike set up for touring is 19". The mountain bike is going to have you more upright. I have heard it suggested that if you are to use your mountain bike for touring consider going up one size in the mountain bike than you would normally be fit with, since the top tube is sloping there will still be plenty of room for stand over height but the larger size will give you a longer effective top tube and hence lay you out in a slightly more aerodynamic road position but probably still not as much as the road bike. The BEST thing to do is test ride and then test ride some more until you find what is most comfortable for you. No one here can tell you that

  3. #3
    Banned wagathon's Avatar
    Join Date
    Apr 2005
    Posts
    1,728
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It probably wouldn't be easy looking for a MTB with 27" tires; maybe go for a MTB with 29s.

  4. #4
    Senior Member
    Join Date
    Sep 2001
    Location
    Montreal
    My Bikes
    Peugeot Hybrid, Minelli Hybrid
    Posts
    6,521
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Get one with the distance from seat to bars close to that on your road bike. Distance seat to pedals can then be easily adjusted

  5. #5
    Senior Member staehpj1's Avatar
    Join Date
    Aug 2006
    Location
    Parkville, Md
    Posts
    7,604
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by barth-karl View Post
    Do you say 'screw it' and just use taller seat posts...?
    Yes, but I do that on my road bikes too.

  6. #6
    Senior Member wahoonc's Avatar
    Join Date
    Jan 2005
    Location
    On the road-USA
    My Bikes
    Giant Excursion, Raleigh Sports, Raleigh R.S.W. Compact, Motobecane? and about 20 more! OMG
    Posts
    16,247
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by robow View Post
    Most people will ride a mountain bike which is sized smaller than their road bike. Such as in inches, my road bike is 22" and my mountain bike set up for touring is 19". The mountain bike is going to have you more upright. I have heard it suggested that if you are to use your mountain bike for touring consider going up one size in the mountain bike than you would normally be fit with, since the top tube is sloping there will still be plenty of room for stand over height but the larger size will give you a longer effective top tube and hence lay you out in a slightly more aerodynamic road position but probably still not as much as the road bike. The BEST thing to do is test ride and then test ride some more until you find what is most comfortable for you. No one here can tell you that
    Good advice...my road frames run in the 25.5" range my most used MTB is 21" but for touring I would prefer a 23". From what I gather you want the MTB frame for MTB riding to be a few inches smaller so if you have to put a foot down....

    Aaron
    Webshots is bailing out, if you find any of my posts with corrupt picture files and want to see them corrected please let me know. :(

    ISO: A late 1980's Giant Iguana MTB frameset (or complete bike) 23" Red with yellow graphics.

    "Cycling should be a way of life, not a hobby.
    RIDE, YOU FOOL, RIDE!"
    _Nicodemus

    "Steel: nearly a thousand years of metallurgical development
    Aluminum: barely a hundred
    Which one would you rather have under your butt at 30mph?"
    _krazygluon

  7. #7
    Senior Member
    Join Date
    Jul 2003
    Location
    Boulder, CO
    Posts
    7,330
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Silly epistomologist. Try an empirical approach.

    Translation: Go to the bike shop and get a bike fit, and try some bikes. The main things I would look for between regular mountain bike fitting and fitting one to tour on are steering not too fast/twitchy and chainstays long enough so your heels don't hit the panniers, if you are using panniers. If you put all the weight on the back (no front panniers) the steering becomes very light and twitchy on about any bike, so it might be good to be front-rack-enabled. Disc brakes can interfere with rack mounting, also.
    ...

  8. #8
    Senior Member wahoonc's Avatar
    Join Date
    Jan 2005
    Location
    On the road-USA
    My Bikes
    Giant Excursion, Raleigh Sports, Raleigh R.S.W. Compact, Motobecane? and about 20 more! OMG
    Posts
    16,247
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by valygrl View Post
    Silly epistomologist. Try an empirical approach.

    Translation: Go to the bike shop and get a bike fit, and try some bikes. The main things I would look for between regular mountain bike fitting and fitting one to tour on are steering not too fast/twitchy and chainstays long enough so your heels don't hit the panniers, if you are using panniers. If you put all the weight on the back (no front panniers) the steering becomes very light and twitchy on about any bike, so it might be good to be front-rack-enabled. Disc brakes can interfere with rack mounting, also.
    Not too many of the current crop of MTB's would be suitable for touring IMHO. The most suitable seem to be the 80's to early 90's vintage, and not something you would typically find at your LBS. Also FWIW also IMHO the current fitting of bikes is a PITA compared to the older straight tube frames.

    Aaron
    Webshots is bailing out, if you find any of my posts with corrupt picture files and want to see them corrected please let me know. :(

    ISO: A late 1980's Giant Iguana MTB frameset (or complete bike) 23" Red with yellow graphics.

    "Cycling should be a way of life, not a hobby.
    RIDE, YOU FOOL, RIDE!"
    _Nicodemus

    "Steel: nearly a thousand years of metallurgical development
    Aluminum: barely a hundred
    Which one would you rather have under your butt at 30mph?"
    _krazygluon

  9. #9
    cyclopath vik's Avatar
    Join Date
    Apr 2006
    Location
    Victoria, BC
    My Bikes
    Surly Krampus, Surly Straggler, Pivot Mach 6, Bike Friday Tikit, Bike Friday Tandem, Santa Cruz Nomad
    Posts
    5,235
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by AndrewP View Post
    Get one with the distance from seat to bars close to that on your road bike. Distance seat to pedals can then be easily adjusted
    +1

    If you are looking at new bikes have a look at the manufacturer's specs. They should provide an effective top tube or horizontal top tube distance. Size it based on this value as you'll have bags of stand over on any MTB frame.

    When I got my Thorn Sherpa frame I used the top tube length on my LHT to size it that way. I've got both bikes setup very similarly. The only difference is my Sherpa has 7" of exposed seat post and my LHT has 3.5"

    If you are buying used just measure the horizontal top tube to compare bikes.
    safe riding - Vik
    VikApproved

  10. #10
    WATERFORD22
    Join Date
    Oct 2005
    Location
    Seattle
    My Bikes
    Bilenky, Co-Motion, 1969 Paramount, Waterford Adventure Cycle, Waterford rs 22, 1980 Davidson etc.
    Posts
    509
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Well,

    It's a interesting question - first comment retro mountain bikes have a different geometry than the current vintages, many have longer angeles less sloping top tube. That's why they can be good touring candidates. Did a mid 80's Miyata up build last year - it measured up identically to my road frame great fit, just got with a mid 80's Stowe which should of been huge at 20 inches it's to small - just got a early 90's Trek 750 which is a hybrid 700 and I am hoping at 21 inches it fits. I agree I am not sure the majority current mountain bikes will make good touring bikes

  11. #11
    Senior Member
    Join Date
    Jan 2004
    Posts
    619
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Effective top tube length is probably the best way to size a mountain bike, or hybrid bike. With the standover so low on those frames, you can go up a size without worrying too much, if that is what you want to do.

    If you get a bike with a sloping top tube, you will be showing a bit of seatpost even when the bike fits correctly. 8 inches or more is not uncommon. There is nothing wrong with doing that.

    In terms of whether or not they would make good touring bikes, I am not sure that the riding position would be so great. Also, the smaller frames might not be easy to mount a lot of racks or panniers to. And the smaller wheels are less efficient, which might be noticeable over long distances. I would get a road-style bike myself.

    EDIT: If you do get a mountain frame, get a rigid one without suspension of any kind, and also a rigid fork. Suspension will make it very hard to mount panniers, especially in the back.

  12. #12
    eternalvoyage
    Join Date
    Feb 2007
    Posts
    2,422
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by barth-karl View Post
    Not that I am operating out a modern assumptions of knowable truths, or a belief in a platonic form of bike size.

    Just wondering what the popular theories are - do you use an MTB frame with measurements close to that of your road frame?

    Many MTBs seem to have sloping DTs- would this mean finding a much larger than normal road sized frame?

    Do you say 'screw it' and just use taller seat posts...?

    Interested in your thoughts
    Older MTBs/ATBs have features that make them more suitable as touring bikes.

Posting Permissions

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