Author Topic: Speaking of Speedometers (Read 4690 times)

mbevo1 · **on:** July 14, 2009, 08:23:07 pm

Well, I broke down and spent $19.95 on a digital bicycle speedo - you enter the circumference of the tire down to the mm and in counts the revs with a magnetic trigger on a spoke. They claim accuracy of .1 mph. Has a trip odometer and clock, too !

Size is about an inch and a half square... shoudn't get in the way of anything.

Should be here and installed by the weekend. I'll let y'all know if it works...

Mike and Stumpy in Michigan

1Blackwolf1 · **Reply #1 on:** July 14, 2009, 08:42:28 pm

They work well, put one on the Whizzer wannabee I built. Worst part is you have to get the magnet very close to the pick-up unit. I think the Scwinn I bought is less than 3/8" from the pick-up unit. Good luck, Will.

mbevo1 · **Reply #2 on:** July 14, 2009, 08:50:06 pm

It's worth a shot... my speedo seems to read about 7 mph high at 55. Seems to be about 10% high across the board. Would like something a little more accurate to cut down on the math...

I think the model I'm getting has a maintenance interval timer in it, too. Would be nice to have a reminder to fill up so I don't forget before starting my 30 mile slog towards home with NO gas stations enroute...

Mike and Stumpy in Michigan

ace.cafe · **Reply #3 on:** July 14, 2009, 08:52:21 pm

My OEM Bullet speedo seems to vary with the weather.
Recently, in this hot weather, it reads almost perfectly. Within 1-2 mph at cruising speeds.
In the cold winter, it reads 10mph too fast.
In the spring and fall, it's in between those two extremes.

I just use my tach now.

bob bezin · **Reply #4 on:** July 14, 2009, 08:53:57 pm

wow maybe my bike really was doing 95 mph.!!?

soulforge · **Reply #5 on:** July 15, 2009, 12:48:19 am

Many km gauge speedos in Korea seem to fluctuate when speed goes above 80km/h(50miles/h). Since we use km instead of mile here, we tried changing them with new ones but after a few 1000 kms they all have the same symptoms again. We just assume it's because of the vibration of the RE (and the poor quality of the speedo

)
Keep us up with your digital speedo experience! We might love to change all the problematic speedos.

luoma · **Reply #6 on:** July 15, 2009, 02:34:54 am

Mine fluctuates at sixty. Up until then, it's pretty close to right on. At 60, it just wobbles back and forth. I can't enev judge by estimating the middle of the wobble. If it's dancing back and forth between 60 & 70, I can speed up significantly and there is no change. I'm sort of used to it now, but it is still aggrevating at times. Maybe I should get a bike speedo too.

Geirskogul · **Reply #7 on:** July 15, 2009, 05:10:15 am

Magnetism is effected by temperature, so this explains the differences in different weather.

Ice · **Reply #8 on:** July 15, 2009, 05:20:52 am

Also metal parts and the clearances between them expand and contract with changes in temperature. As the distance between the magnets and the "bell" they revolve arond changes and the "pull of the magnets is a wee bit lesser or greater.

1Blackwolf1 · **Reply #9 on:** July 15, 2009, 07:06:56 am

Quote from: mbevo1 on July 14, 2009, 08:50:06 pm

It's worth a shot... my speedo seems to read about 7 mph high at 55. Seems to be about 10% high across the board. Would like something a little more accurate to cut down on the math...

I think the model I'm getting has a maintenance interval timer in it, too. Would be nice to have a reminder to fill up so I don't forget before starting my 30 mile slog towards home with NO gas stations enroute...

Mike and Stumpy in Michigan

I bought the cheapo Schwinn model at Wally World for $10 and it has a trip meter, clock and some other features. Will.

mbevo1 · **Reply #10 on:** July 15, 2009, 02:07:56 pm

Didn't even think to check Wally World... Mine hasn't arrived, yet. As usual, I paid $19.95 last Friday, and found the same vendor has dropped the price to $15.58 today !

Mike and Stumpy in Michigan

1Blackwolf1 · **Reply #11 on:** July 15, 2009, 02:18:10 pm

That's what usually happens to me..buy something and next day it goes on sale in a different store for 50% off. Will.

rick505 · **Reply #12 on:** July 15, 2009, 11:22:42 pm

That mostly happened to me right after I bought my bike and purchased accessories from our host. Now unless it's important, I wait. I wonder what will be on sale this Christmas season. Let's speculate. Ok perhaps not.

Rick

mbevo1 · **Reply #13 on:** July 16, 2009, 01:17:34 pm

Quote from: rick505 on July 15, 2009, 11:22:42 pm

Now unless it's important, I wait.

Gotcha, Rick...

Problem is, once I start thinkin' 'bout it, it seems REAL important...

Mike and Stumpy in Michigan

REpozer · **Reply #14 on:** July 16, 2009, 04:39:21 pm

My speedo cable slipped out ( the innards)while I had the front wheel off.
I pulled the cable out and then reinstalled it ( pushed back in)while lubricating the cable with 30w oil.

luoma · **Reply #15 on:** July 25, 2009, 11:29:06 pm

I tried a bicycle computer today. A cheap Schwinn from Wally World like a few others on this thread have mentioned. I measured the radius of a 26 in mountain bike wheel and it appeared to be the same as my 19 in front on the RE, so I calibrated it as such (please correct me if I'm wrong). I attached the magnet fairly close to the hub so that it would be as close to the ppick-up as possible, but obviously not close enough, because I get no reading. Any suggestions?

1Blackwolf1 · **Reply #16 on:** July 26, 2009, 12:00:43 pm

I have the same cheapo on my Whizzer copy. It has to almost touch to pick-up the impulse. Maybe on a motorcycle it could be glued/bonded to the rim so it is close enough. Just went and did a rough measurement, looks to be about 1/16th of an inch space between the mag and readout unit. Will.

soulforge · **Reply #17 on:** July 27, 2009, 12:27:47 am

I'm also trying to install one too.
What I have found is that since it is for bicycle the usuall magnetic is very weak, thus requires the sensor to be as close as possible.
I am trying out some strong industrial magnetics instead of the original weak one.
Before installing, check if you get a reading and check the maximum distance between magnetic and sensor.
I am installing mine on the rear tire. The sensor is attached to the chain cover.
Still checking for the optimum radius though, because I was wondering whether different radius selection would differ the results,
Good luck. Bong

1Blackwolf1 · **Reply #18 on:** July 27, 2009, 12:47:29 am

Yes it will I mis entered the value the first time and had to re-enter when I was getting somewhere around 50 mph on my Whizzer. Re-entered the value and got 21 mph, more believable for a 2 1/2 hp engine. Will.

luoma · **Reply #19 on:** July 31, 2009, 07:30:58 pm

I got a bike speedo to work. I had to use a stringer magney and hot glue it to the edge of the rim. That got it close enough. As it turns out, my speedo was a bit optimistic at lower speeds, then shows accurate at 50-55, then becomes pesimistic at higher speeds. Obviously a faulty magnetic pick-up inside the speedo. At an indicated 60-62 mph, I am actually going 68-70. No wonder my friend on his Kaw complains that I like to ride too fast.

geoffbaker · **Reply #20 on:** July 31, 2009, 10:52:08 pm

Congrats, that's the first speedo I've heard of that wasn't ridiculously optimistic through the whole range!

Mine was consistently about ten percent on the plus side. I always imagined the factory set it that way to keep the speeders happy

luoma · **Reply #21 on:** August 01, 2009, 12:51:12 am

I wish mine was consistently optimistic geoff. At least I could compensate for that. Mine worked OK up to about 50-60, then went bananas. I think one of the intenal magnets came loose and slipped out of place.

1Blackwolf1 · **Reply #22 on:** August 01, 2009, 03:28:18 am

I'd go get a Smiths replica but wonder if they are any closer to correct, (also like the backwards dial). And with losing losing some illumination, don't want a double whammy, ..inaccurate and dim and night. What more could you ask for? WIll.

mbevo1 · **Reply #23 on:** August 18, 2009, 04:03:02 pm

Well...

I goofed around with the Sigma speedo I bought online - couldn't make it work. Called the vendor and they agreed with my speculation that the sensor wasn't working. Shipped it back and picked up a Schwinn model at Wally World.

Used one of the Radio Shack rare earth magnets (3/16" but STRONG) and superglued it to the rim. Glued the pickup to a small dowel to get the spacing right and zipped the pickup to a fender stay. Measured a circumference of 1994 mm for the front wheel.

I LIKE IT ! Speed is within 1 mph of GPS and the trip odometer is nicer than my mileage posit note on the handelbar clamp.

Turns out, my stock speedo indicates 5 mph high from 30-45 and about 7mph high up to 55. Seldom go faster than that, so haven't checked.

Best $10 project I've had in a while...

Mike and Stumpy in Michigan

Author Topic: Speaking of Speedometers (Read 4690 times)

geoffbaker