Talk me down!

[pooks]

Because I'm more frustrated and defeated than I would have ever dreamed, and I cut my ride short and "jumped." Well, got off the bike.

Okay, so I've measured my mileage by the odometer on my car, driving the routes and then sticking to them. I've kept careful logs of my mileage, and frankly it's the mileage that has kept me motivated. Knowing that on the next ride I'd cross over 50 miles, or that if I rode three laps I'd hit 70 (total since I bought the bike, I mean), etc.

I assumed that getting my bike computer would be even better, because I'd be thinking, "Oh, 2/10ths more of a mile, and I'll have ridden another mile, I won't stop now," instead of thinking in terms of "routes" I'd be thinking in terms of miles and tenths of miles.

Except.

My 2.2 mile route? According to my Catseye Astrale is 1.68!

I am beside myself. I'm hoping that somebody will say, "Oh you just need to calibrate your computer, that's no big deal," but am afraid somebody will say, "Bike computers are more accurate than your car, so you probably haven't ridden as far as you think you have."

In which case I need somebody to REALLY talk me down, because right now if that's the case, I'm feel so defeated.

Damn.

(Plus, if my car's odometer is that off, good grief, that's criminal!)

Help!

[mimitabby]

there's got to be someplace near you where there are mileage signs. Ride your bike that 1 mile and see how your cat's eye compares.
Or take it to your LBS and have them help you with it!
m

[hiker chick]

Did you calibrate your computer for wheel size? I had to do that recently when I installed a bike computer.

The wrong setting could make a big difference.

[pooks]

It was installed at REI, but I'll call them and ask. Thanks. This has got to be the problem. I mean, my car couldn't be THAT wrong!

[makbike]

Pooks:

I find that my car and bike computer never agree. I read someplace, I don't remember where, that a lot of different factors go into how accurate your car's odometer is (i.e. if tires are properly inflated). I drove a route the other day and according to my odometer it was 22.6 miles, I took my bike out yesterday rode the exact same route and it came out to be 23.66. Make sure your computer is properly calibrated and don't be discouraged. Stay focused on what you have accomplished thus far. Keep riding and enjoy yourself.

[Geonz]

Different numbers don't change what you've done at all. However, if your car were that far off, I think you'd have k nown it by now. It's a lot easier for a bike 'puter to be off.

Another option - but also not totally reliable - go to "google pedometer" and zoom in on your route. (Since all my speedometers are broken, it's what I ahve to do whenever I ride a dfferent route to get my mileage.)

[sydney_b]

I use http://www.gmaps-pedometer.com for my routes. Now, it may or may not agree with the bike computer, but it's at least consistent and since I use it for all the routes, then I have some sort of measurement system.

You can also save your routes so you can share or refer back to them. I keep a list on my del.icio.us
http://del.icio.us/sydspinnin/Routes

[pooks]

Oh good -- I love all these resources!

In the meantime I called REI and they said no way there should be that much difference between bike and car odometers, so I'm taking it in for them to either adjust or confirm. And if they confirm -- Honda and I need to have a little talk!

[Grog]

Oh good -- I love all these resources!

In the meantime I called REI and they said no way there should be that much difference between bike and car odometers, so I'm taking it in for them to either adjust or confirm. And if they confirm -- Honda and I need to have a little talk!

Don't you have the manual for your computer?

It's super easy to adjust it. You will have to reset it and start over. You just need to have the right wheel size number.

For example, the number for my 700 X 23C wheels (road bike) is 2098, which stands for 2098 millimeters, or 2,098 meters. In other words, each time my wheels make a complete turn (and each time the computer magnet on my spoke passes by the sensor, which sends a "click" to my bike computer), I gain 2,098 meters. (Approximately 7 feet.)

The number for your wheel size will be in the instruction manual of your computer, as well as the instructions to reset it.

[MomOnBike]

Well, if it's any consolation, DH & I went for a 50+ mile ride July 4, and when we got back, he'd ridden about a mile further than I had, and had ridden faster, to boot.

He said that he'd been riding circles around me, but, really, I'd remember that, right?

Sombody around here has some calibratin' to do, too.

[TsPoet]

Pooks,
I've had 2 bike computers installed by LBS - both were set up wrong.
So, what to do:
Line the bike up on a seam in your driveway (if you've got one), lay out a tape measure and start rolling the bike. Use the valve as your start point. roll one revolution and measure the distance. Do this 3 times to make sure it's accurate. Multiply the inches by 25.4 to convert to mm and program that in as your wheel size.
The roll out method is much more accurate than any of the calculations. Also, try to make sure your tires have the air you usually run in them, and if you sit on it while you roll it out that will help even more.
This is better than using tables etc because every wheel has a slightly different depth, regardless of the size (700, 26", whatever are not all equal within a class).

[SouthernBelle]

Another site to use to check your miles, www.routeslips.com

[Geonz]

Now that's a detail person! Can I hire you??

[pooks]

Pooks,
I've had 2 bike computers installed by LBS - both were set up wrong.
So, what to do:
Line the bike up on a seam in your driveway (if you've got one), lay out a tape measure and start rolling the bike. Use the valve as your start point. roll one revolution and measure the distance. Do this 3 times to make sure it's accurate. Multiply the inches by 25.4 to convert to mm and program that in as your wheel size.
The roll out method is much more accurate than any of the calculations. Also, try to make sure your tires have the air you usually run in them, and if you sit on it while you roll it out that will help even more.
This is better than using tables etc because every wheel has a slightly different depth, regardless of the size (700, 26", whatever are not all equal within a class).

Guess what! The guy at REI told me that's what he's going to do, and he's glad I'm bringing it back because he wants to demonstrate that method to the other guys in the shop!

Pooks

ETA: I don't have the manual. It has disappeared. My husband threw out a bunch of magazines over the weekend, and the instructions to install the Astrale must have gone with them -- which is why I gave up and took it to REI to install yesterday. They did say they'd photocopy the instructions for me so I'd have them. I forgot to do that while I was there yesterday. Must remember today!

[Bad JuJu]

Another idea, if you don't have a seam (or a driveway), is to mark your tire with something greasy that will show up well on pavement--a bright lipstick that you no longer use is a good choice. Then do the roll-out method as TsPoet described it (make sure you're ON your bike when you do this--that will make a difference), and just measure the distance between the two marks made by the lipstick on your tire. I measure center to center.

This method has always worked well for me. I check it against the mile markers on a local rail trail, and while it's not perfect, it's always pretty darn close--I'm talking a couple of hundredths of a mile off. I know you're getting it done at REI this time, but after this, you can easily do it yourself and save a trip to REI.