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While it's best to buy through fitting a bike in store, it's not always possible (discussed here).

On some websites, the stand-over height of a bike may not be listed as part of the specifications.

However, simple geometry would dictate that there must be a way to calculate the stand-over height from knowing the frameset's tube lengths and angles, as well as the wheel diameter alone.

Or is there more to consider?


For example, taking the Genesis Day One Disc in the 60 cm variant as an example:

Genesis Day One Disc - Stand-Over

  1. Seat tube (centre-top): 600mm
  2. Effective Top Tube: 575mm
  3. Head Tube: 185mm
  4. Head Angle: 71.5°
  5. Seat Angle: 74°
  6. Chain Stay: 415mm
  7. BB Drop: 64mm

    Stem Length: 110mm

    H/Bar Width: 44cm


That's more or less OK, but what size are the wheels?

  • Hubs: KT-SY1F / KT-MX7R 6-Bolt Disc
  • Rims: Alex XD-Lite Disc 32H
  • Tires: Continental Cyclocross Race 35c (wire)


I would like to know the standover in order to determine clearance between my crotch and the top tube.

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Seems like it would be impossible without having the angle of the top tube. If you think about just dropping the top tube to a lower height, you could do that without changing any of the other numbers that are given. –  Kibbee May 17 '13 at 19:54
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Are you looking for the actual standover height, or the conceptual standover height, were it a conventional frame? –  Daniel R Hicks May 17 '13 at 20:06
    
@Kibbee - I think the actual height of the middle of the top tube above can be calculated from the above if you're also given the dimension between top tube and the top of the seat tube, and between top tube and the top of the headset –  Daniel R Hicks May 17 '13 at 20:09
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@DanielRHicks Yes, It would most likely be possible, these numbers don't show that value. If you had a picture of the frame, you could probably estimate it based on some of the other measurements. Although now that I think about it, if you had a decent picture of the bike, you could probably get a good idea of the standover height from just one simple measurement and inferring the scale of the picture. –  Kibbee May 21 '13 at 0:02
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@Kibbee - Yep, with a large picture and the dimension of one tube you should be able to get the standover height pretty accurately, just by figuring proportions. A little iffy on the small pictures you're often given, though. –  Daniel R Hicks May 21 '13 at 0:53

1 Answer 1

A good approximation can be made using some basic trigonometry and common sense.

I will use WR as wheel radius (i.e. half the wheel diameter) and the numbers refer to the distance indicated in the picture you uploaded.

First of all, the height of the vertical tube (aka the vertical projection of the tube) is just sin(5)*1.

Then the distance between the ground and the bottom bracket is WR - 8.

So, the distance from the ground to the top tube would be H = sin(5)*1 + (WR - 8)

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Basic trigonometry? Isn't that a contradiction in terms? –  jimirings Jul 9 '13 at 14:48

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