OLD Cat Eye calibration

[Wound Up]

Hello Group

I've finally gotten my Trek 1400 tuned up and back on the road after 8 long
years. Man, am I sore. It feels great to get back on it and start training
again. I've forgotten how much I love it.

I have a 10-year-old Cat Eye Enduro - CC-ST250. I bought it in 1994 with
the bike. I've looked Cat Eye's site at their "older model" PDF's for
cyclometers, but none of them gives me the calibration number in centimeters
for a 700x26C tire. They list 700x25 and 700x28 as 211 and 214,
respectively. I guess it should be 212. Is this right? It's been so long
I can't remember. I have Googled as well. No dice.

Another tidbit - the sidewall says, plain as day, 700x26C. The receipt I
from the bike shop says "700x28-35 1 1/8-1/4". These are Kenda Kontenders.
Are these sizes at all equivalent? Should it be 214 or am I ok with
guessing 212? Forgive me if that sounds dumb.

Many thanks in advance

--
Wound Up

 

[Leo Lichtman]

"Wound Up" wrote: (clip) They list 700x25 and 700x28 as 211 and 214,
respectively. I guess it should be 212. Is this right? (clip)
^^^^^^^^^^^^^
Those numbers they give represent the circumference of the tire in
centimeters. You will be very close using the "guess" of 212. The total
difference between 211 and 214 is only 1.4%. You could measure the tire
diameter and calculate the circumference, or, if you want to get really
picky, you could roll out the circumference on a sidewalk.

 

[Wound Up]

"Leo Lichtman" <[email protected]> wrote in message
news:[email protected]...
>
> "Wound Up" wrote: (clip) They list 700x25 and 700x28 as 211 and 214,
> respectively. I guess it should be 212. Is this right? (clip)
> ^^^^^^^^^^^^^
> Those numbers they give represent the circumference of the tire in
> centimeters. You will be very close using the "guess" of 212. The total
> difference between 211 and 214 is only 1.4%. You could measure the tire
> diameter and calculate the circumference, or, if you want to get really
> picky, you could roll out the circumference on a sidewalk.

I see... good deal. I read about people riding through a dab of paint (to
compress the tires during measurement), and other really fussy methods to
get it precisely measured. I may try something like that, but if 212 is
about as close as I'd likely get... it's good enough for me.

Thanks a lot!

--
Wound Up

 

[Mike Yankee]

If you want to be deadly accurate, set it at any reasonably close value
(~214), and try this.

Find a straight section of highway with surveyed mile markers, and ride
a measured distance with your cyclometer in Trip Mode (shows hundredths
of miles). Do this several times in case there's any discrepancy.

Suppose you ride 3 miles according to these very accurate markers. If
your cyclometer shows 3.00 miles, your adjustment was perfect. If it
shows 2.97 miles, for example, whatever circumference number you put in
was 1% low and should be increased by 1% (e.g., from 214 to 216).

I have Cateyes on several bikes, and find that 211 is spot-on for 700 x
23 Axial Pro's. On my touring bike with 700 x 32 Panaracer Paselas
(actuallly 28 mm), the setting works out to 213.

 

[Jasper Janssen]

On Wed, 17 Aug 2005 03:50:28 GMT, "Wound Up" <[email protected]>
wrote:

>Another tidbit - the sidewall says, plain as day, 700x26C. The receipt I
>from the bike shop says "700x28-35 1 1/8-1/4". These are Kenda Kontenders.
>Are these sizes at all equivalent?

That looks like a tube measurement, actually -- suitable for 700C tires in
widths from 28 to 35. "28 x 1 1/8 x 1 1/4" is the original 700C, aka
700C-37 aka 622/37. Ideally, you'll want to use ETRTO numbers, which for
most wheels are 622/nn (sometimes written as nn-622 or a permutation), or
for MTB wheels 559/nn. See also Sheldon's tyre sizing article.

I wouldn't worry too much about the receipt having a weird number on it,
though, as long as the price is correct.


Jasper

 

[Wound Up]

"Mike Yankee" <[email protected]> wrote in message
news:[email protected]...
> If you want to be deadly accurate, set it at any reasonably close value
> (~214), and try this.
>
> Find a straight section of highway with surveyed mile markers, and ride
> a measured distance with your cyclometer in Trip Mode (shows hundredths
> of miles). Do this several times in case there's any discrepancy.
>
> Suppose you ride 3 miles according to these very accurate markers. If
> your cyclometer shows 3.00 miles, your adjustment was perfect. If it
> shows 2.97 miles, for example, whatever circumference number you put in
> was 1% low and should be increased by 1% (e.g., from 214 to 216).

There's a brand new, wide 55 mph two-lane right near the place I'm riding
where I can easily do this. I'm going to see if I can do that tonight,
using the 212 number suggested previously as very close to correct.

> I have Cateyes on several bikes, and find that 211 is spot-on for 700 x
> 23 Axial Pro's. On my touring bike with 700 x 32 Panaracer Paselas
> (actuallly 28 mm), the setting works out to 213.

I want to get it as close to dead on as I can. Thanks for the tip!!

--
Wound Up

 

[Wound Up]

"Jasper Janssen" <[email protected]> wrote in message
news:[email protected]...
> On Wed, 17 Aug 2005 03:50:28 GMT, "Wound Up" <[email protected]>
> wrote:
>
>>Another tidbit - the sidewall says, plain as day, 700x26C. The receipt I
>>from the bike shop says "700x28-35 1 1/8-1/4". These are Kenda
>>Kontenders.
>>Are these sizes at all equivalent?
>
> That looks like a tube measurement, actually -- suitable for 700C tires in
> widths from 28 to 35. "28 x 1 1/8 x 1 1/4" is the original 700C, aka
> 700C-37 aka 622/37.

That makes sense, especially now that I take a closer look and see "tube" =)

Ideally, you'll want to use ETRTO numbers, which for
> most wheels are 622/nn (sometimes written as nn-622 or a permutation), or
> for MTB wheels 559/nn. See also Sheldon's tyre sizing article.
>
> I wouldn't worry too much about the receipt having a weird number on it,
> though, as long as the price is correct.

Yeah, that's what they quoted me.

Thanks

--
Wound Up

 

[531Aussie]

"I want to get it as close to dead on as I can.

The only real way to get it right is to do an 'on the bike' roll out on ameasured track or path.

I've found on my Cateyes (Mity 2 and Tomo XC), using 20mm and 23mm tyres, is that the best figure is slightly less than recommended. I put in 208