Hmm. Can someone help me with my cyclocomputer?
 

I just picked up a Cateye enduro 8 last week and I thought I set it right but I was way off (did a 12 mile trail which read as a 9.5).

Ok here's what I'm having problems with. On the sidewall of my front tire it says "26 X 47/52" now the 26 is obvious but whats up with the 47/52?

The circumference guide that came with the comp has these incruments (these are the closest, theirs MANY more but its irrelivent to put them all here):

26 x 7/8
26 x 1(59)
26 x 1(65)
26 x 1.25

I reset it today and set it to the 26x7/8's one but I'm not sure if thats right. Anyone have any advice?

Thanks

The guide is really only good for nominal sizes and gives you a ballpark figure. The best method is to do an actual rollout calibration. Remember to do the rollout with you actually on the bike and the tyre pressure at what you would normally ride with. Check out the following thread for some good tips on how to do this:

http://www.bikeforums.net/showthread...threadid=34538

Hmm, did'nt even think of doing that. Thanks

47/52 is used by some mfg's (Wilderness Trail Bikes for example)instead of the more familair inch dimensions. It denotes the ratio of tread width to wall height I think. 47/52 is probably closest in size to a 26" x 2.1" tire.

getting the sensor mounted just right is tricky. i've got a cateye 3, and it took me awhile to figure out that their "5 mm" recommendation was a crock, and it needed to be closer to 2 mm or so. this makes bumps problematical, because a bump can knock the magnet just a little, thus screwing up the read.

if it's really quiet, you can hear the sensor 'click' as you pass the magnet by it. i do this before every ride, rotating the wheel so it goes back and forth, tick, tick etc. if it's missing ticks as the magnet goes by, i tweak it a little.

also, i can usually tell when it's wacked out when i'm riding. if i'm riding a steady pace, and the speed seems to be jumping back and forth between two different speeds pretty regularly (14 and 17 mph for instance), i know the sensor isn't picking up every rotation and needs adjusting.

ten years ago i had a computer on my mountain bike, and it was a pain in the butt too. the sensor technology is just pathetic, at least for the two different brands of computer i've tried. but the cateye works as long as i keep an eye on it.

oh, and the stated accuracy of these things is something like .1 mile per 10 miles, so it's never going to be dead on.

Hmm, good info guys, thanks.

I did the roll out test and the c ended up bieng 206.05.... which is way off what I thought it would be.. kinda funky. But I'm going to take it on trail that I know is exactly 1.8 miles tomorrow.

Another gotcha is if you swap to a different wheelset that uses different pressure and tire size. In practice, I don't think it makes a big difference but the purest in you suggests you want to calibrate it just right and that's ok.

I used to calibrate mine at normal pressure but without me on the bike. Once I tried the proper calibration of pressure any me on it, there was about an 8% variance. Mind you, once I switched from being a roadie to mtb I dropped the pooter and use my watch instead and time my outings if I need to.