Bicycle Sizing Notes

A quick note on bicycle sizing: Bicycle sizing sight-unseen is a black art. A bit of voodoo if you will.

The best way to be sure about bicycle fit is to ride it and find it comfortable – an uncomfortable bike will become nothing but a dust collector. There is some math, however, that can guide you to the right size.

Measuring Yourself:

The first thing you have to do is measure your proper medical inseam, otherwise known as your Pubic Bone Height (PBH). Your PBH is the height of your actual pubic bone, measured in centimeters, while standing barefoot on the flat ground. This is not your pants inseam – you must measure this accurately. For a complete guide to finding your PBH, please see the Rivendell Bicycle Works website.

Once you have this number, you can easily determine which bikes are too big, which are too small, and which fall into your approximate comfort range.

Measuring The Bike – city bikes, road bikes, comfort bikes, etc:

Enter your measured PBH in cm:

Standover Height – This is the height of the top tube (cross bar) of the bike above the ground. I post this number for most of our used bikes, and most manufacturers include this number in their published frame geometry charts. Don’t pick a bike with a standover greater than your PBH, as you’ll “nut yourself” when you dismount. Most of the time you’ll want a few centimeters of clearance there. For step-through (aka girls’ style) frames, the measured standover is not a good indicator. I’ll often quote an “effective” standover, giving a measurement of where the top tube would be if it existed – this is just to help compare ballpark sizes.

Saddle Height – Take your PBH in cm and subtract 10.5. This gives an ideal saddle height, give or take a half centimeter in either direction. (Thanks again to Rivendell for the method and numbers). For a sight-unseen purchase, you can use the seat tube length measurement from the manufacturer’s specs in order to determine if your saddle height can be comfortably accommodated on any given bike. Most manufacturers quote seat tube length as the distance from the centre of the bottom bracket (the point about which the pedals rotate) to the top edge of the top tube. (Note, however, that some measure to the very top of the seat tube where it sticks out of the frame, and some measure to the centerline of the top tube).  WHat you need to determine from the charts, or from a measurement on the bike, is the distance from the centre of the bottom bracket to the top of the actual top tube. You should pick a bike with a seat tube length that allows for a few centimeters of exposed seat post, plus the height of the saddle itself. Subtracting 15cm from your ideal saddle height should put you in the right ballpark. You can adjust this number if you want to use a super low profile racing seat, or a double sprung 20cm tall Brooks B190.

Top Tube Length, Seat Tube Angle, Bottom Bracket Height, and all those other numbers on the geometry charts – For most day to day utility cyclists, these numbers don’t matter much. They most certainly affect the type of ride the bike will provide, but unless top performance is your number one priority, don’t worry too much about them. I will mention, however, that a lower seat tube angle and a longer head tube length generally signal a more relaxed comfort-oriented geometry. So you can keep those in the back of your mind.

BMX bikes, Mountain Bikes, Tallbikes, Recumbents, etc – The above information is for standard road/city/hybrid/utility bikes. Downhill mountain bikes, full syuspension bikes, BMX and other outliers can not be sized this way. And remember, in the end it’s about the ride – if it’s not comfortable, you won’t ride it. So a nice long test ride is a vital part of the process.

Please share this page: These icons link to social bookmarking sites where readers can share and discover new web pages.
  • TwitThis
  • Facebook
  • email
Subscribe to blog posts via email or via RSS.
Posted in Articles
29 comments on “Bicycle Sizing Notes
  1. henery says:

    Freelance Graphic Designer
    Thanks for this awesome post!!

  2. corby says:

    Pevonia Spot Treatment
    So wonderful article!!

  3. ChrisJor says:

    Party Cruises : Thanks! Really wonderful piece of information.

  4. Kelly says:

    Best Hunting Rifle
    Amazing post!! Awaiting for the next one.

  5. Your site is so, interesting and brilliant one dear. I am first time visiting your website and feel that your website is so, interesting one so, i would like to visit again and again keep it up dear.

  6. Shanon says:

    My husband and i ended up being very cheerful when Ervin could finish off his investigation through the ideas he came across from your weblog. It is now and again perplexing to simply happen to be giving out key points which others could have been trying to sell. So we know we have you to be grateful to because of that. The explanations you made, the straightforward web site navigation, the friendships you help foster � it is many fabulous, and it�s helping our son and the family know that this idea is fun, and that�s incredibly vital. Thanks for all the pieces!

  7. Williams says:

    Cyprus Mobile Application Development
    Awesome it is. Keep updating us always.

  8. Amazing post!! Awaiting for the next one.

  9. William says:

    Home Insurance Quote Miami
    Good job. Keep it up !!

  10. Mary Currier says:

    This article is something that will help me with my class assignment. It helped me to better understand another aspect of this topic. Thanks!
    Online training and courses

  11. Informative post !! Thanks for sharing!!

  12. rickyy26 says:

    Drafting Services Perth

    Informative article, Keep sharing !!

  13. master says:

    incredible blog.. I really like it ..Discount Codes UK

  14. Joey says:

    Pure Natural Healing is the step-by-step instructions that teach you how to develop a daily routine and to restore your natural healing experience.
    Pure Natural Healing Review

  15. james says:

    •Pure Natural Healing teaches you self healing in a simplified and simple method, through art therapy. Lightly massage the disorder from the body and get liberty from drugs, operation and life threatening disabilities.

    pure natural healing review

  16. Samuel says:

    Thanks for this awesome post!!
    Web Design Cyprus

  17. Its a great one and also a beautifully crafted one. looking forward for more from this website.I read all of article of the site the article was very nice go and check it out!

  18. Makayla says:

    Sydney Kitchen Renovations

    Interesting blog…impressing…..

  19. It is not all bad luck but if you know the reason you can get over it.
    Survive In Bed Review

  20. Julius says:

    Electrical Appliances Perth

    Thank you for this nice post. Really incredible post.

  21. Makayla says:

    LED Lights For Kitchen Cabinets

    Thank you for this nice sharing.

  22. Doggy Dans says:

    With the permission of the admin I will pass these information to my students. doggy dans online dog trainer review thank you

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>