Hey folk, finally got my 17:43 chain conversion on, and after a couple hundred miles with it in town and on the highway I couldn't be happier with it!  I went with the steep 17:43 instead of the lower 17:45 despite my 250+ weight; because I was pretty sure the thumper could handle it on takeoff, and I wanted it to putt along nice and lazy on the highway. All has worked out just fine so far, and I don't see any problem loading another 50 pounds of gear for traveling (which I usually go pretty light on what I haul when traveling).

I went ahead and splurged on a cheap eBay o-ring chain and ended up with a bit over $100 in the conversion. On top of the conversion I've just added new tires and maxed out the rear tire size.

Now I'm awaiting my National Cycle 4.5mm Dakota windshield and I'll be about halfway home to a long haul road version of the Savage!

One thing still has me vexed though: In an attempt to keep my speeds reasonably legal, I added a Schwinn digital speedometer, and it seems to be good up to about 40-mph or so; then the readings go all whacky.

It never ever shows anything over 60mph, like it is stuck in the high 50s even when I'm passing everything on the expressway... (probably running 80mph).  I don't know what to think, I've moved the magnet and pickup around a couple of times, and triple checked the math on my wheel diameter input, and nothing seems to help? Anyone have a clue as to what I might be doing wrong? Or maybe I go a bad speedometer unit?

TIA to anyone who can help with the speedo!

verslagen1 wrote on 08/22/08 at 21:51:30:



I don't know how accurate it is at lower speeds... just guessing I'd say it is reading slow at low speeds.

I can't get the magnet much closer, it's within about 1/8" now... Maybe I will try the stronger Rat Shack magnet thing, but I don't think proximity is the problem. Dunno though, I'm at a loss.  

This may sound obvious, but what is the range of that Schwinn speedo?
If it never goes past 60, maybe it's because it can't!!!
I know the Sigma's will (at least mine did), but that doesn't say all of them go that high.
After all.. when was the last time you saw a bicycle doing 40mph?

Besides that, the suggestions made by others are good ones.

youzguyz wrote on 08/23/08 at 02:09:53:


I have done at least twice, once in a group ride (100 mile round trip, the posted speed was 40, chippies pulled us over gave us a warning) and once solo for an hour (yep one L of a tail wind)  

How about flipping the magnet over?

Where on the wheel is the magnet mounted?

The closer to the axle, the slower the speed of the magnet, making it easier to register - if it's - say near the spoke nipple, it will fly by the sensor, perhaps not registering as often. The computer is going to sample for signal so many timer per second - each time, it will sample - (true or false) - if false, it probably assumes that the magnet hasn't made it around yet - in that split second that it's not sampling the magent can wiz by.

Putting it close to the axle may help at hwy speeds, but may disrupt readings in town.

Or, print this topic off and keep it with you - when the cops pull you over and ask you why your'e speeding - hand 'em this thread - I'm sure they'll understand