Bicycle Mechanics - Can I install a cyclocomputer myself?

I'm sure all 6,844 members (and counting) of bikeforums know by now that I'm not very mechanically inclined. However, I finally found my cyclocomputer- it's an Axiom Cyclocomputer 8.0C. I'm wondering how hard it really is, or do I need some special calibrating machines or some kind of protractor or something along those lines?

If not, it's off to Yojimbo's sometime next week! :D

Koffee

It shouldn't be too difficult. Make sure you position the sensor as per instructions. Also I would suggest doing a rollout calibration rather than relying on predetermined charts. Basically you will need to input the diameter of the wheel into the computer and the best way to do this is to mark the rollout on the ground and measure it. Do this 10 times and average out the numbers. Some bike computers only have a certain "resolution" so you will have to input the number that matches as closely as possible to your available choices. Some excellent suggestions for installing bike computers can be found on Sheldon Brown's website.

http://www.sheldonbrown.com/cyclecomputer_installation.html

Unless it is a weird computer you should be able to do it yourself, if you want a good clean look your lbs may be a better idea.

The Sheldon Brown site has good information. The job is about the simplest accessory you can install; OK, a handlebar bag might be a little easier ;).

Good luck,
Mel

Originally posted by djbowen1
Unless it is a weird computer you should be able to do it yourself, if you want a good clean look your lbs may be a better idea.

What difference does it make if there is a wire or not? You just going have to zip tie it or wrap it around the cables. Installation is the easy part out of the whole procedure! The hardest and most important thing is to set the rite wheel size, and figure out how all the functions work. Your comp's menu should guide you through the set up. One of the easiest mistakes to make is to set the magnet on the spoke and sensor on the fork to far apart. Good luck! :beer:

Originally posted by Chuvak
What difference does it make if there is a wire or not?

I think the poster said "weird" and not "wired". I can see some computer installs being a bit more complicated such as ones that have crank sensors or need to interface with the shifters (Shimano FlightDeck and Campy ErgoBrain).

One other note... if you have a suspension fork (assuming front fork mounting) then you will of course want to leave a little slack in the cable (assuming wired sensor) to account for the suspension travel.

Originally posted by Mel
The Sheldon Brown site has good information. The job is about the simplest accessory you can install; OK, a handlebar bag might be a little easier ;).

I disagree. Stickers are the easiest! :D

Me reading to fast, when will I learn?:rolleyes:

<sigh>

What is rollout clearance? Is it possible to get a tape measurer out and just straight up measure the diameter using the D= 2pi r squared formula or something?

Thanks to everyone so far!

Koffee

Girl, you can do anything you set your mind to. And if you need a little technical advice...you know you can have it.

Originally posted by Koffee Brown
What is rollout clearance? Is it possible to get a tape measurer out and just straight up measure the diameter using the D= 2pi r squared formula or something?

You'd think that'd be the right way to do it but real-world factours often produce errors this way. It is best to to measure not only the actual rollout linearly on the ground but also with you on the bike as the tyre diameter will be slightly less when loaded. I personally use the valve stem as a reference point. Line up the valve stem vertically and place a mark on the ground. Roll the tyre one to three full revolutions so that the valve stem is once again vertical. Measure the distance from the beginning and divide by the number of revolutions. Repeat this 10 more times and average.

BTW, even properly and carefully calibrated bike computers aren't extremely accurate. Expect a certain degree of error.

http://www.neebu.net/~khuon/albums/2003STP/PICT0002.jpg

Well... maybe the patch was off?

;)

:D

Thanks. I am going to work up the courage to do this on my own. I need to learn anyway....

Koffee

Koffee - it's straightforward, even I managed it :)

Just remember when setting the rollout to err on the right side of mileage (i.e round up the distance rather than down ;) )

Richard

Koffee,
"YOU CAN DO IT!" it may look ard but its not that bad, i would try. If you fail just bring it into a shop, but i dont think you will fail.

good luck
-ross

Yes. It's one of the easier and more satisfying DIY bike projects. For a professional finished look, coil the excess wire around the brake cable ousing.

You can, you will do it!

- Look at the instructions, especially for the minimum/maximum distance between the spoke magnet and the 'pick-up'.
- I would start the wiring operation at the fork/chain stay (whatever is applicable), rather than at the handlebar/computer mount. This makes it a little easier to save the excess wire for last, when you can wrap it around your brake cable.
- Keep the wires under the tubes as much as possible (visually better).
- Make sure that there is enough wire at the headtube/downtube intersection; your front wheel should make full turns (in both directions) without overly stressing the wire. While riding, you won't need this slack, but one days you/somebody lifts up your bike and starts swinging it--your 'puter wires will not survive then.
- Verify that the 'puter is picking up all the necessary signals before finally tightening the wires with tie-straps/tape. A bike stand and/or a friend assisting you comes in handy.
- Follow all the good calibration advice out there...

Good luck doing it!

As we say up here Koffee, it's a scoosh!

Just do it.

Originally posted by khuon
Some excellent suggestions for installing bike computers can be found on Sheldon Brown's website.

http://www.sheldonbrown.com/cyclecomputer_installation.html


THANK YOU FOR POINTING ME TO SHELDON'S Site!!!!!

he has wheel sizes for 16" wheels, found on some recumbents.
thanks!!!!

:D

Be very careful...
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you could break a nail. :D :D :D


Sorry Koffee....couldn't resist. :beer: You can do it....it's a piece of cake.

koffee, feel free to ignore khuon's very helpful advice about doing a rollout. if you want the best accuracy, khuon's right. but it's not absolutely necessary, you can just plug in the values the manual says to plug in. this will get you pretty close, and these computers aren't exactly perfect in the best of situations. i think mine claims 1/10th of a mile per 10 miles, something like that. i just plugged in the numbers for a 700x23 wheel and it's been reasonably similar to my car odometer (which isn't perfect either). perhaps one day i will do a rollout, but if i'm going to get on my bike for three revolutions of the wheel, i might as way stay on. :)

if you notice your speed changes radically back and forth, like from 14 to 17 mph and back, within the space of a few seconds, the sensor probably isn't close enough. my Cateye claimed the magnet had to be within 5mm of the sensor, but it really needs something like 2mm. which means occasional hard jolts will knock it out of alignment, creating the weird speedometer readings stated above, and causing me to get off my bike and tweak the magnet a little.

it's pretty easy. realistically speaking it's more involved than putting on a wedge bag or even a water bottle cage, but it's not rocket science.