For example, seen on the Reid Cycles website

  • 2
    Bike geometry terms are mostly standardized, but there can be variations in what they are called. On geometry charts for US road bikes, I don’t recall ever seeing the term rear center length. Most people would give the chain stay length. I agree with Michael’s answer that they are most likely synonyms. PS, i agree that the terms can be confusing, but I have actually seen geo charts that are positively cryptic, like older Colnago and even current Pinarello charts. Best practice is usually to give a diagram, which Reid Cycles failed to do.
    – Weiwen Ng
    Jul 10, 2020 at 12:07

1 Answer 1


Rear Center Length

It’s the distance from the rear hub to the bottom bracket. More or less the chainstay length.

Unfortunately Reid Cycles doesn’t have a diagram of what and where exactly they are measuring. For example top tube length could be the actual tube length or a “virtual” top tube length (like in the diagram below) if the top tube were completely horizontal.

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  • Thanks! I thought stack and reach were quite important measurements, but Reid cycles omit them
    – Don
    Jul 11, 2020 at 11:43
  • 1
    Yes, that’s their biggest mistake. All the other measurements are more or less meaningless (at least for non-frame builders) except maybe front wheel trail (for how stable it steers) and seat stay length (for how much space you have for panniers).
    – Michael
    Jul 11, 2020 at 14:06

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