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Computer Drops Readings While Out of Seat? Common?(7 posts)

Computer Drops Readings While Out of Seat? Common?SingleThreaded
May 24, 2002 7:30 AM
I'm trying to isolate and fix a persistent problem with my Cateye Astrale. Whenever I'm out of the seat cranking, I'll see both RPMS and speed dropping precipitously, ~30-50 RPM drop and 3-10 MPH and return back once back in the seat. I know I'm not doing any of these deceleration/accelerations, in some cases I know I am accelerating when the computer is dropping reading.

I'm trying to identify whether it's the rear wheel, the frame or computer and cabling. I'm curious, is this common with most computers? Or just those on twisting frames and wheels.

I'm trying to be a Lance-like when climbing, but the computer is making me look like his granny.
re: Computer Drops Readings While Out of Seat? Common?curlybike
May 24, 2002 7:40 AM
Make sure that the pickup and magnet are close to the hub, this will reduce errors caused by frame and wheel flex, which I feel is your situation. You may be able to fiddle and get the magnet closer to the sweet spot of the pickup. Some computers get touchy when the battery is going south (cr2032). Are you using a flexy wheel with minimum spokes?
re: Computer Drops Readings While Out of Seat? Common?SingleThreaded
May 24, 2002 7:52 AM
My pickups are as close as I can get them without hearing the contact on each revolution. I suspected the battery early on and replaced it, but the problem remained. I ride Bontrager Race Lites with 24 spoke count on the rear wheel. These wheels have paired offset spokes which results in the pickup being a bit twisted on the wheel.
re: Computer Drops Readings While Out of Seat? Common?curlybike
May 24, 2002 11:22 AM
Are the pickups close to the axle. That was part of the post that you did not respond to. The closer to the axle the more stable everything is and the more time that the magnet has to trip the sensor.
re: Computer Drops Readings While Out of Seat? Common?SingleThreaded
May 25, 2002 6:40 AM
Ah yes. I missed your reference to the hub. That's a good idea. I have it mounted quite oppositely to what you recommended. If flex is a problem that's probably one of the best solutions, not to mention the recommended way to mount. I'll try it and tell you what happens.
re: Computer Drops ReadingsChen2
May 24, 2002 7:32 PM
Have you tried cleaning the contacts between the computer and its mount? I've run Astrales for many years and have had a few problems like yours when the contacts were wet or dirty. I don't know why coming off the saddle would make any difference, but it sure won't hurt to try cleaning the contacts.
Moisture is another problem ...SingleThreaded
May 25, 2002 6:53 AM
Actually another good solution to resolve another problem. I ripped the computer off my Dad's 10 year old MTB which had been sitting a stone's throw from the ocean -- I'm sure it's got salt water scum all over. Wet days do have me constantly fiddling with the computer but generally when it drops out on wet days the readings go to zero.

My problem with drop reading out of the saddle results in knocking out 30-60% of the readings and it knocks out both speed and rpms. I suspect the mounting mod, as recommended by the previous post, should minimize the flex and provide increased time for the slower passing pickup.

I'd like to think the missed reading are a result of me spinning so fast, but I suspect it's more because of my weight (240 lbs).