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Old 08-10-16 | 05:58 PM
  #3  
jambon
Senior Member
 
Joined: Jul 2014
Posts: 397
Likes: 1
From: Ireland
Originally Posted by CliffordK
Not Quite.

A lot can be adjusted with seat and stem adjustments, but the frames are slightly different

From the chart:
60cm:
ST Angle: 72.5, HT Angle: 72, TT Length: 594.8, HT Length: 189, Reach: 403, Wheelbase: 1085.3

62cm:
ST Angle: 72, HT Angle: 72, TT Length, 603.9, HT Length: 210, Reach: 401, Wheelbase: 1095.3

So, the head tube of the 62cm bike is 21mm longer.

A bit of old math: SOH CAH TOA, so Cos(angle) = Adjacent/Hypotenuse.
COS(72) = A/21, A = 6.5mm

So, if you raise the stem on the 60cm bike by 21mm, you effectively shorten the reach by 6.5mm, so the reach is actually effectively about 4.5mm shorter on the 60cm frame when adjusted for HT height as would be expected.

Note the 60cm frame has a slightly steeper seat tube, which can be adjusted for by using more setback with the seatpost.

So, the 62cm frame has a slightly longer wheelbase (10mm), which I think is all in the TT length, and thus less toe overlap.

Hmm... do all the angles and lengths add up?
But the difference in the head tube sizes only becomes a factor if you plan to have your stem set lower on the steerer than the 21 mm difference would allow , the head tube angles are equal , the head tube size difference just means 21 mm less steerer will show on the larger size ?
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