Thursday, November 10, 2011

Finally using the Cateye Micro Wireless on my Brompton

I've had a Cateye Micro Wireless cycle computer for quite some time now (it used to be on my Trek Valencia) and I had always meant to attach in on my Brompton, but didn't. All along, I thought the computer and the sensor would get in the way of the bike's fold.

After much procrastination, I finally decided to use it. It was easy to mount the computer on the M-bar and attaching the analog sensor on the fork using zipties I bought at the hardware store.

And surprise, surprise, the computer and analog sensor did not get in the way of the fold. Not at all.

A problem came up, though, in inputing the wheel circumference [L (mm)] unto the computer. The Cateye Manual that came with it did not have a computation for the Brompton's tire size (16 x 1 3/8).

Fortunately, there's the internet. I found Sheldon Brown's Cyclecomputer Calibration Chart and there it was! 16 x 1 3/8 = 1282! So I entered that in the Cateye Micro Wireless and rode the bike to test if the code was correct. I biked to a place which I knew was 1 kilometer from my house, and when I got there the reading was 1 kilometer. Excellent!
I used the Cateye Micro Wireless Cycle Computer in my recent bike tour of Ilocos Norte. It was useful because I knew how fast I was going, my pace, and the time and distance I covered. It gave me a more informed perspective of the ride, which is always good. 


  1. Hi - how does it make sense that 16 x 1.375 wheel size gives 1282? If you look at the cateye tire circumference reference guide,,

    clearly the 16x 1.5 (which is larger than a brompton is only 1185, and 16x1.75 is 1195... but you think it should be 1282?

    Let me know thoughts. ... intuitively it just doesn't make sense.

    i am trying to figure out what the correct imput is for my strada and brompton

  2. Hi, mliu! My only reference for using 1282 was Sheldon Brown's chart. I haven't actually calculated the exact equivalent of 16 x 1 3/8. You may be correct that the Brompton's wheel circumference could be smaller than 1282. However, since using the 1282 code, the reading has been quite accurate. Do let me know the real wheel circumference when you know. Thanks!

    1. Hi Kris,

      I bought a cateye wireless strada recently for my bike as well, and I stumbled onto your website while looking for the answer to the same question that you asked since the manual did not have a computation for the Brompton's tyre configurations.

      I did a search again and I stumbled across a more comprehensive table for the CATEYE website:

      Officially, the wheel circumference for the Brompton tyre should be 1300. :) Guess the debate is resolved!

      Best regards,

  3. Hi there I've measured the circumference by wrapping inch-tape around the wheel and I got 1320 mm (measured 3 times, with the tape pretty tight)
    ... That's close to what you can find in here:;wap2 but they calculate from diameter, which is hard to get precisely, so my measurement is better I'd say.

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    2. I've forgotten to say that I have Schwalbe Marathon tires.

      ..and btw: happy owner of SIGMA BC 1609 STS

  4. 1320, 1300, 1282 I measured 1330 (tyres at correct pressure). So, am I doing 23mph, or only 22? I gots to know man.

    1. I'd go for the middle ground, passerby. 1300. :)

  5. Just measured a fairly new Schwalbe Marathon (35-349) at 1278 mm. Didn't take note of the tire pressure but tire give was minimal. Hope this helps.