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Main Area => General GS500 Discussion => Topic started by: tripleb on September 30, 2007, 12:51:22 PM

Title: new sigma bicycle computer
Post by: tripleb on September 30, 2007, 12:51:22 PM
I just bought a new Sigma Sport BC 1606L to compliment the OEM speedo.  I got it for only $30 shipped.  Anyone have one of these?

http://www.sigmasport.com/en/produkte/bikecomputer/topline_wired/bc1606l/?punkt=features (http://www.sigmasport.com/en/produkte/bikecomputer/topline_wired/bc1606l/?punkt=features)
Title: Re: new sigma bicycle computer
Post by: kml.krk on September 30, 2007, 02:14:08 PM
I don't have any but I'm thinking about getting one of those. Let me know how you installed it and how well it works.
Thanks
Title: Re: new sigma bicycle computer
Post by: 510 on September 30, 2007, 09:13:47 PM
I got the cheapest model, the 506, mainly for the time display and a more accurate speedo.

It's attached to the left handlebar, to the right of the headlight/turn signal box. The cable is routed through the speedo cable holders, and the sensor is zip-tied to the left fork near the wheel. The magnet is epoxied to the plastic cover. I can post some pics later if you guys would ilke.

Main gripe is that it doesn't have a backlight, so it's reaaally hard to read at night.
Title: Re: new sigma bicycle computer
Post by: bombadillo on September 30, 2007, 11:08:54 PM
How do you adjust for the wheel size difference between a bike and a bicycle???  I have a wireless shimano unit for my road bike here and never tried to hook it up, but figured I couldn't adjust the difference.
Title: Re: new sigma bicycle computer
Post by: Jay_wolf on October 01, 2007, 07:44:59 AM
Its done in MM or something, on my acewell ,its 1357 . for a 17 inch wheel
Title: Re: new sigma bicycle computer
Post by: kml.krk on October 01, 2007, 10:30:04 AM
Quote from: 510 on September 30, 2007, 09:13:47 PM
I got the cheapest model, the 506, mainly for the time display and a more accurate speedo.

It's attached to the left handlebar, to the right of the headlight/turn signal box. The cable is routed through the speedo cable holders, and the sensor is zip-tied to the left fork near the wheel. The magnet is epoxied to the plastic cover. I can post some pics later if you guys would ilke.

Main gripe is that it doesn't have a backlight, so it's reaaally hard to read at night.

please post some pictures. I'd like to see them
thanks
Title: Re: new sigma bicycle computer
Post by: Jay_wolf on October 01, 2007, 11:41:23 AM
(http://i167.photobucket.com/albums/u148/James_Jay_Wolf/30062007475.jpg)

Close Up


(http://i167.photobucket.com/albums/u148/James_Jay_Wolf/16072007560.jpg)

Mounted
Title: Re: new sigma bicycle computer
Post by: 510 on October 01, 2007, 12:18:41 PM
Sorry for crappy quality - cell phone cam.

Also, please ignore the fact that the gauges are strapped to the top triple using zip ties... it's temporary  ;)

(http://xtal.als.lbl.gov/sigma1.jpg)
(http://xtal.als.lbl.gov/sigma2.jpg)
Title: Re: new sigma bicycle computer
Post by: tripleb on October 03, 2007, 06:26:24 PM
I got the computer and the rare earth magnets.  I'm going to install them tomorrow after work and let you know how it works out.  Here's some pics.

(http://pktdo.com/GS500/sigma2.jpg)    (http://pktdo.com/GS500/magnets.jpg)
Title: Re: new sigma bicycle computer
Post by: Suzuk-E on October 04, 2007, 02:12:20 AM
Are any of those back lit?

Title: Re: new sigma bicycle computer
Post by: kml.krk on October 04, 2007, 10:07:02 AM
yep the new model 1606 has a back light
cheers
KaMeL
Title: Re: new sigma bicycle computer
Post by: Jay_wolf on October 04, 2007, 11:52:59 AM
The Acewell Backlight is Blue!
Title: Re: new sigma bicycle computer
Post by: Absolute Rescue on October 04, 2007, 12:29:27 PM
Quote from: 510 on October 01, 2007, 12:18:41 PM
Sorry for crappy quality - cell phone cam.

Also, please ignore the fact that the gauges are strapped to the top triple using zip ties... it's temporary  ;)


HAHA did the same exact thing with my gauges when I put clip ons on...ended up being permenant cause i'm lazy :oops:
Title: Re: new sigma bicycle computer
Post by: tripleb on October 04, 2007, 05:43:50 PM
I installed it today although I haven't finished it completely yet.  Here's some pics of the semi-finished product.  BTW, it seems to work really well so far and does have a really nice backilight.  I'm going to use the zip ties to run it along the brake cable and remove the electrical tape once the epoxy cures.

(http://pktdo.com/GS500/sig1.jpg)(http://pktdo.com/GS500/sig2.jpg)(http://pktdo.com/GS500/sig3.jpg)
Title: Re: new sigma bicycle computer
Post by: toyopete on October 04, 2007, 05:44:38 PM
Quote from: 510 on September 30, 2007, 09:13:47 PM
I got the cheapest model, the 506, mainly for the time display and a more accurate speedo.

It's attached to the left handlebar, to the right of the headlight/turn signal box. The cable is routed through the speedo cable holders, and the sensor is zip-tied to the left fork near the wheel. The magnet is epoxied to the plastic cover. I can post some pics later if you guys would ilke.

Main gripe is that it doesn't have a backlight, so it's reaaally hard to read at night.

I love it, fails backlight indeed
Title: Re: new sigma bicycle computer
Post by: tripleb on October 07, 2007, 05:16:17 PM
well I tested it out yesterday and I must've done something wrong.  The computer was reading 60 mph at 7k rpm in 6th.  The bike's speedo was reading about 90 and I think it was most likely closer to the actual speed.  Anyone know what is a ballpark speed for that many rpm's in 6th?
Title: Re: new sigma bicycle computer
Post by: 510 on October 07, 2007, 10:16:25 PM
Quote from: tripleb on October 07, 2007, 05:16:17 PM
well I tested it out yesterday and I must've done something wrong.  The computer was reading 60 mph at 7k rpm in 6th.  The bike's speedo was reading about 90 and I think it was most likely closer to the actual speed.  Anyone know what is a ballpark speed for that many rpm's in 6th?

Did you remember to input your tire size into the computer? I forgot the number that I put in, but it wasn't that accurate anyway. The best way is to mark a position on your wheel, roll it against the ground for a complete revolution, and use tape measure to measure the distance between the start and end. This is more accurate than just measuring the diameter and multiplying that out.

I think Sigma requires this distance to be converted to millimeters. The manual should have more info about this.
Title: Re: new sigma bicycle computer
Post by: tripleb on October 08, 2007, 03:05:17 PM
I did put the tire size at 1357 for tire 1 but didn't put anything in for wheel 2.  I wonder if it's reading wheel 2 for some reason.
Title: Re: new sigma bicycle computer
Post by: tripleb on October 08, 2007, 04:47:11 PM
I measured the diameter of the wheel and it was 70.75 inches which converts to 1797mm.  How is this so different than the figure you're using Jay?
Title: Re: new sigma bicycle computer
Post by: tripleb on October 09, 2007, 05:01:14 PM
I tried it using a wheel size of 1797 and seems much more accurate.
Title: Re: new sigma bicycle computer
Post by: Jay_wolf on October 09, 2007, 06:23:05 PM
My acewell came with a Set of Wheel guides , the Rim is a 17 inch ,so i looked it up  and because its a Magnet epoxyed on to the rim , and the sensor is on the fork leg  it says for a 17 inch wheel, input 1357  admitedly its having its mot soon , as its SORN at the moment i havent got to test it for more than 7 mph lol
Title: Re: new sigma bicycle computer
Post by: tripleb on October 10, 2007, 04:48:27 PM
That's weird.  I rolled the bike out and measured the wheel length that way.

With the 1357mm setting I couldn't get the bike past 60mph on the speedo so you might want to roll yours out for your acewell too.
Title: Re: new sigma bicycle computer
Post by: Kerry on October 10, 2007, 08:50:50 PM
Quote from: Jay_wolf on October 09, 2007, 06:23:05 PM
My acewell came with a Set of Wheel guides , the Rim is a 17 inch ,so i looked it up  and because its a Magnet epoxyed on to the rim , and the sensor is on the fork leg  it says for a 17 inch wheel, input 1357 [...]

What you're saying finally sunk into my brain....  :oops:

Maybe it will help to visualize what happens as the wheel spins.  No matter how far from the axle you mounted the sensor...
        * at the hub
        * halfway up one of the spokes
        * at the edge of the rim
        * at the outer diameter of the tire itself
... the sensor would detect the same number of rotations for a given distance of travel.  That's because all of those "virtual mounting points" rotate at the same rate - after all, they all go around together.  (Imagine if they didn't!  :o)

The important thing for your computer to "know" is the road distance represented by each one of those rotations.  If you had no tire on your rim, and the rim were REALLY 17" in diameter, then 1357mm would be the correct setting:

     circumference = pi x diameter
                   = 3.14159265 x (17 inches x 25.4mm/inch)
                   = 1356.5mm
    (Rounds up to 1357)

However, there are two problems with these numbers.  First, the rim is NOT actually 17 inches in diameter.  I just went out with a tape measure and eyeballed it, and it looks more like 17.5 inches.  But that's OK - I wouldn't recommend testing your computer with no tire mounted on the rim anyway.  :icon_rolleyes:

More importantly, there IS a tire mounted on the rim.  The "eyeballed" diameter for my 110/70-17 BT45 front tire is somewhere around 22 inches, giving the following (estimated) results:

     circumference = pi x diameter
                   = 3.14159265 x (22 inches x 25.4mm/inch)
                   = 1755.5mm


tripleb's circumference figure of 1797mm denotes an actual diameter (for his particular front tire) of 22.5 inches.  So, he's on the right track.  "Roll it out" and measure it!  (An actual circumference measurement will be more accurate than a calculation based on an "eyeballed" diameter. :thumb:)
Title: Re: new sigma bicycle computer
Post by: Cal Price on October 11, 2007, 03:36:02 AM
Cor........now I know why we missed Kerry so much.
Title: Re: new sigma bicycle computer
Post by: OPTheory on October 16, 2007, 08:46:31 PM
Questions for those of you with sigma bicycle computers:  What kind, and how long do the batteries last in these guys?  Do I need to keep pressing a button in order for it to light up or does it automatically light up in the dark?

My speedometer is broken and rather than paying $150 to get it replaced I figured I can get one of these instead.
Title: Re: new sigma bicycle computer
Post by: Jay_wolf on October 16, 2007, 08:58:31 PM
Mines Designed for a motorbike ,so it runs off the battery , and the Light is on all the time , like a stock gauge , u only see it in low light conditions
Title: Re: new sigma bicycle computer
Post by: OPTheory on October 16, 2007, 09:06:58 PM
Quote from: Jay_wolf on October 16, 2007, 08:58:31 PM
Mines Designed for a motorbike ,so it runs off the battery , and the Light is on all the time , like a stock gauge , u only see it in low light conditions

Very nice!  But then again, yours costs the equivalent of $150 vs. the $16 for a bike meter soooo...

It's also a tachometer, right?  How responsive is it to sudden changes?  Is it jumpy? Did you get one because one of your other gauges were broken?

I'm trying to find a place to buy one in the US unless anyone knows of a viable substitute.
Title: Re: new sigma bicycle computer
Post by: tripleb on October 17, 2007, 02:32:33 PM
the sigma isn't permanently backlit so if you ride it at night you'd have to keep pressing a button.  but for only $30 USD its a pretty good deal.  I've only had it for a few weeks, but it works great and I love it.
Title: Re: new sigma bicycle computer
Post by: 510 on October 18, 2007, 01:22:25 AM
Quote from: OPTheory on October 16, 2007, 08:46:31 PM
Questions for those of you with sigma bicycle computers:  What kind, and how long do the batteries last in these guys?  Do I need to keep pressing a button in order for it to light up or does it automatically light up in the dark?

My speedometer is broken and rather than paying $150 to get it replaced I figured I can get one of these instead.

I honestly wouldn't recommend a bike computer as a substitute for a speedometer. It updates pretty infrequently, I think every second or so, and even the backlit models require you to press a button to keep them lit.

If you want a gauge replacement then get a computer designed for a motorcycle, like an Acewell. Or if you have even more money to burn, a Veypor.
Title: Re: new sigma bicycle computer
Post by: Jay_wolf on October 18, 2007, 04:09:19 PM
No well i did it because i wanted a one off bike , but then came the Kat front end ,so it was even better ,

Its a speedo and tach ,no. the tach is spot on ,runs off the Coil ,

it has a bar on it , and a XXXXX rpm .so 7k would be X7000         and 11k  would be 11000

Im putting a Mini Tach on it anyways for when u need to Really Shift at 11.5 or what ever , im sure the acewell would do it , but i like the idea