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 Post subject: Cyclometers?
PostPosted: Thu Jul 29, 2010 12:06 am 
Retro Guru

Joined: Sun Dec 14, 2008 2:11 pm
Posts: 303
Does anybody know of anywhere that sells good old fashioned cyclometers?

I'd be needing one (well actually two) for 700c wheels, I hate cycle computers with a passion and just want a simple cyclometer for clocking up the miles.

Cheers,

Gareth


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 Post subject: Re: Cyclometers?
PostPosted: Thu Jul 29, 2010 6:08 am 
r.B.o.T.M. & P.o.T.M. Winner
r.B.o.T.M. & P.o.T.M. Winner
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Joined: Sun Jul 11, 2010 1:41 pm
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Location: Plymouth, UK
GarethPJ wrote:
Does anybody know of anywhere that sells good old fashioned cyclometers?

I'd be needing one (well actually two) for 700c wheels, I hate cycle computers with a passion and just want a simple cyclometer for clocking up the miles.

Cheers,

Gareth


Evil bay I fear!

I've had manu of these in my time and was always fascinated by them and how they work as a kid.


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 Post subject:
PostPosted: Thu Jul 29, 2010 10:17 am 
Dirt Disciple
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Joined: Wed Dec 09, 2009 5:40 pm
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Location: Leicestershire
I've had these on bikes many years ago but never seen one for 700c wheels. They were made in the day for 27" wheels so would not be accurate for 700c which is 29" I believe. Why not just go for a simple computer. I don't think you'll get much cheaper than this http://cgi.ebay.co.uk/LCD-Bike-Bicycle- ... 27b27b4c18


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 Post subject:
PostPosted: Thu Jul 29, 2010 12:36 pm 
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Joined: Sun Dec 14, 2008 2:11 pm
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guitarpete247 wrote:
I've had these on bikes many years ago but never seen one for 700c wheels. They were made in the day for 27" wheels so would not be accurate for 700c which is 29" I believe. Why not just go for a simple computer. I don't think you'll get much cheaper than this http://cgi.ebay.co.uk/LCD-Bike-Bicycle- ... 27b27b4c18


700c is 29"? Er no, not unless you're running 58mm tyres it's not and you don't find many road bikes with those fitted. For some reason the septics do have a habit of calling 700c wheels 28". but even to reach that size you'd need 45mm tyres. Miraculously a 700x32c (what I have on my tourer) has a rolling radius of 27 inches. The 28c's on my road bike will be a bit under 27" (to the tune of about 1%) which is close enough for jazz. I doubt any computer or cyclometer is any more accurate than that in the first place.

And no they weren't just for 27" wheels. Indeed BITD they were probably more common for 26" wheels in Britain. Cyclometers were available to suit almost every tyre size. Take a look on ebay and you'll see there's one there at the moment for 16" wheels.

My trouble is that nobody seems to manufacture them anymore so you're restricted to NOS. I spoke to one LBS recently who had thrown away a drawer full of cyclometers in all sorts of denominations. They were a bit upset when I told them they could have probably got at least fiver each for them on ebay.


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 Post subject:
PostPosted: Thu Jul 29, 2010 1:52 pm 
Dirt Disciple
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Location: Leicestershire
"1954 mm 76.9 inches 700 C, 28 x 1 5/8, 29 inch
(28 x 1 1/2 F.13 Canada) 622 mm Most newer adult bikes for road use use this size,
including most road bikes and hybrids"
Quote from Sheldon (http://www.sheldonbrown.com/rim-sizing.html)

"29 inch wheels / ISO 622
Main article: 29"er
“29-inch wheels”, which also conform to the popular 700C (622 mm diameter clincher wheel standard) are becoming more popular for not only cyclocross bikes but also cross-country mountain bikes for larger riders. Their rim diameter of 622 mm (~24.5 inch) is identical to most road, hybrid and touring bicycle wheels but are typically reinforced for greater durability in off-road riding. The average 29-inch mountain bike tire has an outside diameter of about 28.5" (724 mm). There are advantages and disadvantages associated with this change discussed in detail in the main article.

700C Road bicycle wheels / ISO 622
Touring, race, and cyclo-cross bicycles may have vastly different design goals for their wheels. The lightest possible weight and optimum aerodynamic performance are beneficial for road bicycles, while for cyclo-cross strength gains importance, and for touring bicycles strength becomes even more important. However this diameter of rim, identical in diameter to the "29er" rim, is by far the most common on these styles of bicycles. It rolls more easily than smaller diameter tires. Road wheels may be designed for tubular or clincher tires, commonly referred to as "700C" tires."
Wikipedia quote (http://en.wikipedia.org/wiki/Bicycle_wh ... 2F_ISO_622) Note with the Wiki quote the same ISO number.

I agree it is very similar in size but when setting up a cycle computer you need to use the figures either on the tyre or in the instructions for it to be accurate.
And if you have been on ebay you will have seen this http://cgi.ebay.co.uk/RARE-FIXIE-RACER- ... 2a08f29bb0 Made for 27" wheels.

They never were that accurate but each to their own I suppose.


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 Post subject:
PostPosted: Thu Jul 29, 2010 3:14 pm 
Retro Guru

Joined: Sun Dec 14, 2008 2:11 pm
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If you are setting up a cycle computer and you want accuracy don't bother with the markings on the sidewall, but measure your tyre. You'd be amazed how much two tyres with the same nominal sizing can differ.

However given that the last cycle computer I tried over read by up to 10% depending on speed, I wouldn't bother too much about accuracy. Basically the faster I went the less accurate it became.

It's for these reasons that I'm not too bothered about deadly accuracy.


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 Post subject:
PostPosted: Fri Jul 30, 2010 7:27 pm 
Retro Guru

Joined: Wed Dec 10, 2008 9:19 am
Posts: 2096
Location: Sheffield, top city
i used to have a belt driven Huret cyclometer that had option for 26 or 27 inches. Surprisingly, the 26 in option was quite accurate with 700C wheels. this model also had a reset button.

The old "striker hits the star" models we had as kids could never be reset, so we couldnt establish trip distances unless we remembered to make a note of the starting mileage.


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