Advertise on Bikeforums.net



User Tag List

View Poll Results: 650 or 700

Voters
10. You may not vote on this poll
  • 650

    3 30.00%
  • 700

    7 70.00%
Results 1 to 12 of 12
  1. #1
    Newbie
    Join Date
    Apr 2014
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    help really appreciated 650c tires on Dawes sst 52cm from BD

    Hi everyone im new here and i purchased a BD Dawes sst i love the bike but noticed i have
    some toe overlap. Now i wanted to purchase new 650c wheelsets.
    Is this a bad idea i feel the smaller wheelsize will give me a better fit.
    some of my concerns are what is the diameter of this wheel size?
    Will the smaller wheel size make the stock brakes useless?
    Im sorry if thisbsounds silly but i appreciate all your feedback!

  2. #2
    Veteran Racer TejanoTrackie's Avatar
    Join Date
    Jul 2009
    Location
    Ciudad de Vacas, Tejas
    My Bikes
    28 frames + 73 wheels
    Posts
    7,945
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Not a good idea. A 650c wheel has a diameter approximately 2" smaller than a 700c wheel, such that the brakes will need to reach another 1" for the brake block to be centered on the rim braking surface. So, much longer reach brake calipers would be required. Also, the handling would be significantly affected due to the change in steering geometry caused by the smaller tire diameter. Finally, the bottom bracket height will be reduced by 1", which will greatly increase the risk of pedal strike when pedalling through corners. You just need to learn how to deal with toe overlap, or buy another bike with less track like geometry that doesn't have any overlap.
    What, Me Worry? - Alfred E. Neuman

    Quote Originally Posted by Dcv View Post
    I'd like to think i have as much money as brains.

  3. #3
    Blaster of Reality Scrodzilla's Avatar
    Join Date
    May 2009
    Location
    San Diego, CA
    Posts
    24,612
    Mentioned
    27 Post(s)
    Tagged
    2 Thread(s)
    Why is this a poll? There isn't one person here who will advise you to foolishly put 650c tires on a bike designed for 700c.

  4. #4
    Newbie
    Join Date
    Apr 2014
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TejanoTrackie View Post
    Not a good idea. A 650c wheel has a diameter approximately 2" smaller than a 700c wheel, such that the brakes will need to reach another 1" for the brake block to be centered on the rim braking surface. So, much longer reach brake calipers would be required. Also, the handling would be significantly affected due to the change in steering geometry caused by the smaller tire diameter. Finally, the bottom bracket height will be reduced by 1", which will greatly increase the risk of pedal strike when pedalling through corners. You just need to learn how to deal with toe overlap, or buy another bike with less track like geometry that doesn't have any overlap.
    Thanks for the help so if i were to put 650c wheels i would also have to change the cranks and install longer reach callipers? Why is steering affected? Also why is this wheel size so disliked?
    Thanks for the response trackie guess ill just deal with it

  5. #5
    Senior Member
    Join Date
    May 2013
    Posts
    224
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Actually i was going to encourage OP to buy a good 650c wheelset and provide my email address. Happy to take them off his hands on the cheap. Or maybe TT will beat me to it. We both have 650c fixed geared bikes

  6. #6
    Grumpy Old Bugga europa's Avatar
    Join Date
    Oct 2006
    Location
    Adelaide, AUSTRALIA
    My Bikes
    Europa, Hillbrick, Road Chief, Repco Superlite (Ol' Rusty)
    Posts
    3,222
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Scrodzilla View Post
    Why is this a poll? There isn't one person here who will advise you to foolishly put 650c tires on a bike designed for 700c.
    Ooooo, that makes it soooo tempting.

    Toe overlap isn't a huge issue DrFx. Sure, if you've got the choice, and it means something to you, choose not to have it but you have a good bike now, don't mess with things on the grounds of toe overlap.

    In normal riding, if you ever turn the wheel far enough for toe overlap to be an issue, you've already fallen off. In very slow speed riding and tight manoevering though, it is possible that the two will overlap at some point. However, it's only for a short period and you are traveling slow enough to anticipate and avoid any problem. Seriously.

    Still tempted to vote 'yes' Calvin_face_evil_smile.gif
    I had a good bike ... so I FIXED it

  7. #7
    Veteran Racer TejanoTrackie's Avatar
    Join Date
    Jul 2009
    Location
    Ciudad de Vacas, Tejas
    My Bikes
    28 frames + 73 wheels
    Posts
    7,945
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DrFx View Post
    Why is steering affected?
    What, Me Worry? - Alfred E. Neuman

    Quote Originally Posted by Dcv View Post
    I'd like to think i have as much money as brains.

  8. #8
    Member rekab's Avatar
    Join Date
    Feb 2014
    Location
    DFW TX
    Posts
    42
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DrFx View Post
    Thanks for the help so if i were to put 650c wheels i would also have to change the cranks and install longer reach callipers? Why is steering affected? Also why is this wheel size so disliked?
    Thanks for the response trackie guess ill just deal with it
    Changing cranks won't help. Putting small wheels in a frame meant for larger wheels will lower the bike to a point that even with short cranks it's more likely to pedal strike
    Yes you'd need different calipers
    650c isn't disliked when used on a frame built for that size wheel.

    You are not the first person to think of this or ask. Yes it'll work with enough modification, but it won't work like the intended part and isn't worth the headache. If you don't like toe overlap (perhaps if you shared your reasoning we could help with the specific issue it's causing) swap for a different frame.

  9. #9
    Blaster of Reality Scrodzilla's Avatar
    Join Date
    May 2009
    Location
    San Diego, CA
    Posts
    24,612
    Mentioned
    27 Post(s)
    Tagged
    2 Thread(s)
    To hell with logic, physics, science, advice, economics and all the related crap. DrFx should just go ahead and do it!

  10. #10
    Senior Member SquidPuppet's Avatar
    Join Date
    Dec 2013
    Location
    Coeur d'Alene
    Posts
    917
    Mentioned
    7 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TejanoTrackie View Post


    Trail will be reduced by over ten percent. If the bike handles "perfectly" now, it will become a twitchy mofo. If it's a twitchy mofo now, it'll become scary as hell.

  11. #11
    Senior Member
    Join Date
    May 2013
    Posts
    224
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Scrodzilla View Post
    To hell with logic, physics, science, advice, economics and all the related crap. DrFx should just go ahead and do it!
    I've come to really love this place. I bet my IQ has dropped 10 pts just from reading the forum Which may put me into the negative numbers.

  12. #12
    Grumpy Old Bugga europa's Avatar
    Join Date
    Oct 2006
    Location
    Adelaide, AUSTRALIA
    My Bikes
    Europa, Hillbrick, Road Chief, Repco Superlite (Ol' Rusty)
    Posts
    3,222
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by TejanoTrackie View Post
    Quote Originally Posted by SquidPuppet View Post


    Trail will be reduced by over ten percent. If the bike handles "perfectly" now, it will become a twitchy mofo. If it's a twitchy mofo now, it'll become scary as hell.
    Maybe we should all vote 'do it provided he provides a video of the results'
    I had a good bike ... so I FIXED it

Posting Permissions

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