Schwinn 12 Function Bike Computer/Speedometer

[Down_South]

I have a question about tire size. see manual link below...

Manual is Here

I have a beach cruiser with a 26" x 1.75" tire, "FAT BOY TIRE", "White wall tire". Does anybody know what ATB stands for? I'm using code 2045. is this the right code.


Special Thanks to K3PGP for the images of the manual

 

[marioaz]

I'm also confused by the wheel size input instructions. Don't know what ATB stands for. It shows 2073 for a 26" wheel. But 26" IS with tire. Then the bottom list is "w/tire". What the? And it only goes to 26"x2. Most 26"x 1.75 wheels use a 2.125 tire. And that's the width, right? What does the width have to do with the diameter? I've been using wheel factor "C", 2073, and it seems correct when I go thru a school zone w/traffic at 15mph.
I'm calling Pacific Cycle tomorrow because the chain guard front bracket cracked on my Point Beach. I'll try to get some tech advise on this portion of the bike computer and report back.

 

[wildemere]

ATB = All Terrain Bicycle.

All the figures on the right are millimeters of circumference.

The figures on the lower left are imperial measurements for common tyres.

The upper inch measurements are the diameter of your wheel and tyre combo

The best way is to rollout the tyre, measure it in mm then input that number.

2050

And what does the Cricket have to do with Guam?

 

[Ghost0]

Diameter of your tire in mm
26in = 660.4mm
Pi = 3.1416
660.4 x 3.1416 = 2074.7

 

[matt167]

2073 is what you need if you go by the chart.. but IIRC, the schwinn speedo's can take any number so use the 2074 like Ghost0 figured...

 

[Ghost0]

I was not suggesting he use that number. I was just providing the formula. My bike has a 26 x 1.75 but the actual diameter of the tire is 25.5 so that is the number I convert to mm and then multiply by Pi to get the correct number. On my Schwinn speedo you can manually enter any number, you don't have to use one of theirs.

 

[Norco John]

Make a mark on your tyre. Set that at the bottom, where it contacts the pavement. Roll the bike until the mark comes around again. Measure that distance in millimeters and enter it into the cyclometer.
Takes less time than trying to find your brand of tyre in some chart.

 

[Down_South]

I took another look at my front tire and its marked as 26 x 2.125. I originally posted 26 x 1.75 - oops. Its a cruiser with a balloon tire. I'm still confused why the width has an effect on diameter, unless there's the squash factor from the weight of the rider when the rubber meets the road. I've used a tape measure to find the radius, it was 13.5 inches under no weight. Under the weight of a rider I'm guessing radius to be 13 inches. So I'm going to use 2074 for now.

 

[TxBikeRider]

Make a mark on your tyre. Set that at the bottom, where it contacts the pavement. Roll the bike until the mark comes around again. Measure that distance in millimeters and enter it into the cyclometer.
Takes less time than trying to find your brand of tyre in some chart.

This is the most accurate way....even better would be to get on the bike and roll it. Believe it or not it changes under load.

 

[seannp22]

ATB stands for At. Tire. Base. It's standard Jargon for people who know about tires basically. I have a motorized bicycle and needed to find that out. I have 26"x1.75" tires and ATB is what you need to use in accordance with the matching size of your tires on the chart, or you can do it the long way like when you buy the computer, it has instructions on how to to it by exact measurements, or you can use the chart. It's pretty self explanatory, I used the chart and got great, accurate results.

 

[skrew37]

Does anyone know the max mph for these? I have one and it seems top out at 31.0mph. Firstly, I know I'm going faster than that and secondly, it's impossible to go exactly 31.0,mph and hold steady, right?

 

[seannp22]

I bought one of these, put the numbers in it, then it was fine. what you have to do if you didn't already know is when you're done installing the magnet and the sensor along with the computer mount itself, you have to find out what the size numbers are for your bike. there is a size numbers reference chart that comes in the package. press and hold both of the buttons and numbers will show up. you can diagnose the numbers for your wheel size yourself, or you can use the reference chart. after you turn it on 4 numbers will appear. (2124) put in the numbers that the size reference chart tells you matches your wheel size. (FAQ, ATB means at tire base.) the right button will change the number. if you miss the number you're trying to enter in the digit you're in, just keep pressing the button. it cycles back around. the digits go from right to left. so it'll be a little weird entering them in. the left button toggles which digit you're entering numbers into. when you're done at the last number, press the left button again. Long story short, you probably either left the numbers alone and/or entered the wrong ones if you think it's reading wrong.

 

[Cabinfever1977]

99mph is probally the max, i had it up around 34.5mph or more on the speedo.

 

[seannp22]

I've topped it out at 42.8 so yeah it goes above 31 most definately lol

 

[cannonball2]

I installed one on my BMW K100 to act as an odometer(the K bikes have odo problems) after calibrating it it reads dead on with the bikes speedo. It good for 88 mph for sure. The info with it says 99mph. Its milage capcity is 10K mi. Still it helps with maintence rather than guessing or logging miles.

 

[skrew37]

I did get it up to 37.8mph today. It stayed at 31.0 for a good distance then jumped to 34, topped out at 37.8 then dropped back down to 31 with no noticeable speed decrease. It could be my sensor so I ordered some rare earth magnets hoping this might help. If not, I'll try a new one or a different one.

 

[cannonball2]

I did get it up to 37.8mph today. It stayed at 31.0 for a good distance then jumped to 34, topped out at 37.8 then dropped back down to 31 with no noticeable speed decrease. It could be my sensor so I ordered some rare earth magnets hoping this might help. If not, I'll try a new one or a different one.

Yeah I am using a rare earth magnet on the BMW, with those distance between the magnet and the sensor is not so critical. One I have on a bike seems to hunt back and forth on speed. Check you max speed its in there.

 

[skrew37]

That's good to know that maybe the stronger magnets will fix the jumping around of the reading problem... I lost my manual so I didn't see that it went up to 99mph. How do I check my max speed? Since I lost the manual, I'm afraid to push any buttons as I don't want to accidentally reset the odometer...

 

[seannp22]

It'll jump around just a little bit just because it's a low voltage device, so don't worry about it unless it's jumping around REALLY bad. like when my battery went dead I'd be going at a speed of let's say 10. it would take some time to get up to 10, and then when I'd stop for some reason it'd keep going like the information had to catch up to the computer 'cause it was reading too fast. (low battery response.) and to look at all of your different modes, press the right button repeatedly until you've reached the mode you want to look at. you''ll only reset the odometer changing the battery or holding both the right and left buttons.

 

[cannonball2]

These things are a little slow to up date on something that acclerates pretty well. There are a couple of versions of these I bought a few off ebay that look identical for $9 shipped. They work well and look exactly like the Schwinn. You can reset the tire size on them by pressing both buttons and it leaves the rest of the info alone. The Schwinn I have will zero the clock and odo.