Speedometer discrepancy
 

I thought I'd start a post about the Speedometer discrepancy on our US CSC Cyclone RX-3

It seems to be off quite a bit...

As for methods to make it closer to correct....

A larger front wheel (Probably a 21" to make up about a 15% error)

Or some kind of digital converter to vary the signal from the sending unit on the front hub.

Anyone have other ideals?


(I hate to think it's adding miles to my odometer that I'm not doing...when it reads 1,000 miles, we will have only gone 870...)

If it uses a magnetic pickup there may be a way to program it to read correctly.

It does use a magnetic pickup.....

Thanks for starting the new thread on an important topic, Huck. :)

I am going to check my odometer against a measured mile to determine its accuracy. If both speedometer and odometer are 'optimistic,' we might be able to find a find a box which adjusts the digital input for both. If only the speedometer is 'optimistic,' we will need to find a way to calibrate the Siemens microprocessor. ;)

My Trail Tech Vapor computer can be programmed for the circumference of the wheel. This input allows you to very accurately calibrate the speedometer on that computer. :) If we can figure out how to access the microprocessor in the Siemens speedometer, we might be able to calibrate it, also. ;)

Spud, did you buy a connector for the Siemens ALDL port?

No, I didn't buy that connector. ;)

The company 12 O'clock Labs sells a unit called the SpeedoDRD.

http://shop.12oclocklabs.com/index.p...&product_id=59

https://www.youtube.com/watch?v=iScrjr7FxDM

Here is a link to a review of the SpeedoDRD.

http://www.wrrdualsport.com/reviews-...s/97-speedodrd

I rode from Lawas to Papar via Keningau (in Sabah, Malaysia), and a quick check on Google Maps showed the distance to be 220km.

I checked my odometer upon refilling at Papar, and it clocked at 240km.

However, this is by no means a detailed test, merely an afterthought, after stumbling upon this thread.

But I believe the odometer is accurate, at least roughly, because on another route, the distance is about the same on my Zong as it is on my Keeway TX200G.

YMMV.

Thanks for posting your input, Jezzrite. :)

Your information indicates the speedometer is about 9 percent 'optimistic.' That is consistent with the information we are getting in the United States. :)

new zong
 

great news that device will prob fix our speedo problem. I still could use some help figuring where the 6 pin electrical box that came with the uprade dash goes. The usb an cig lighter plug right in to the 2 plugs that are between the stock dash and windshield.Also am still hoping csc shows where you mount the upper end of the spring for the centerstand ,,it appears you have to drill the frame ,,,but i'd like confirmation ,before doing so. Btw the box does say ''DC12v-DC5v /1A
/

I suggest you start new threads on both those topics, Fish. Better yet, I'm confident you can get quick answers if you call Ryan at CSC. :)

zong rx3
 

will do spud,,, i emailed them the same question.Tire question for you .did you use the xact size tires when you replaced the stockers ,,,while looking at 17'' shinko s our exact size wasnt listed in the one i wanted.

Please ask that question in the megathread, and I'll answer it over there. :) I bet other people might have the same question, and more people will find the answer there, than here. ;) The megathread is a nice gathering place for quick questions and general information. The tire information will get lost here, in a thread about speedometer discrepancy. ;)

http://www.chinariders.net/showthrea...13440&page=219

That is a really slick little unit! A great idea as well since almost all motorcycles have overly optimistic speedometers... Lol, they should sell them in bulk packs! ;)

I agree, it's a great little unit, but it certainly is expensive. :wtf: I bet they can manufacture that item for $10. ;)

Yup, doesn't really look like there's much to it does there? They make big money on specialty items!

I've been looking for a better deal than $70, but I don't think I will find one. :ohno: At this price, I am inclined to keep my current practice. I multiply the speedometer reading by 0.10, and subtract the product. ;)

However, it is very nice you can reprogram the unit any time you like to reflect a difference in tire size, tread depth, et cetera. :)

I can't help but think that the answer lies in tapping into the Siemens CPU. I'm betting that a connector and some laptop software will do the trick.

I once used a programmer to correct the speedometer in a buddy's '98 Chev Astro van; the process took a long time, but it was very easy. He had new gears installed for towing, so the electronic speedometer needed to be adjusted to compensate.

Some electronic speedos can be recalibrated simply by putting them in set-up mode and punching in the correct wheel diameter. May take a 16 year old to figure out how to do it though. Could be as simple as holding down both buttons while turning the key on, but probably not.

Maybe one of the RX3 owners would care to email Siemens and ask. Perhaps they'll respond.

I will contact them by telephone on Monday, and see if they can refer me to someone who can help. ;)

speedo fix
 

well if someone gets one a speedo fixer units ,,does theirs an it works,,i would pay half ,, get it sent to me, then send it back,,,share it twice ,,an its free for the original purchaser.

The SpeedoDRD does not reprogram the Siemens microprocessor. This unit merely modifies the input sent from the magnetic pickup to the speedometer. Therefore, it must remain in place. ;)

I couldn't contact Siemens by telephone today. I guess they are in an eastern time zone, and they were closed when I called. I will try calling them again, tomorrow. In the meanwhile, I sent them an email. However, I am pessimistic they will be either willing, or able, to tell us how to reprogram the Siemens speedometer for better accuracy. :shrug:

The SpeedoDRD will certainly work if we install it between the magnetic pickup line and the speedometer. The SpeedoDRD will plug into the connector behind the headlight, and under the dashboard itself. :)

There's always hope. As well, I'm confident that the group here will figure it out eventually.

I was pleasantly surprised, but I actually received a quick response from Siemens regarding the RX3 digital speedometer. :) After exchanging several emails, I received this final reply.

Unfortunate [sic], we do not have any documentation on that speedometer, you will have to go to the OEM for info.

Interesting. Does that mean the speedometer unit is not connected to the Siemens CPU?

I have tried starting the bike while holding down each individual button, and both buttons. Unfortunately, none of these attempts put the speedometer into calibration mode. :ohno:

I'm sure the speedometer is connected to the Siemens microprocessor. However, the Siemens VDO Speedometers sold in the United States have one button, and are set up to enter configuration mode as described by Mudflap. The details of the configuration mode for the U.S. units are provided in the two documents I have linked below.

http://www.nsifleet.com/pdf/ProgrammableSpeedometer.pdf

http://www.springfieldstreetrod.com/...ionsSpeedo.htm

I remained convinced that it must be calibratable. I'm hopeful that the talented people here will sort it out.

I'm almost inclined to 'bite the bullet,' and get the SpeedoDRD. ;) If someone has a good idea how to calibrate the Siemens CPU, please let me know. :)

Try turing the key on but not starting the engine, then hold individual and combinations of buttons. I had a compass you had to hold the button down, then power up.

I have an ideal on a "fix" for this, when I finally get around to trying it out, I'll post back results....

should change from 14% high to about 5% low...so it would read about 53 mph when you were actually doing 55 mph, opposed to the current "reading 62 mph when you are actually doing 55 mph"

Thanks for the input, but I think I have tried every possible combination of pressing buttons, both while starting the speedometer, and after the speedometer is running. I have performed all these experiments while the engine was not running.

Thank you, but please don't tease us. :hehe: Would you mind telling me your idea? If not publicly, would you send me a personal message? :)

I'm pretty sure the RX3 employs a 3-wire, Hall Effect sensor. The SpeedoDRD receives this signal, then modifies the output rate to the speedometer, as shown below.

http://i442.photobucket.com/albums/q...psf2rgg0bd.png

If someone knows of a microchip which performs a stepdown function of about 10 percent, we can build our own speedometer calibration unit. :) The only benefit of the SpeedoDRD is its ability to program the unit for different size wheels and tires. ;)

For example, here is a speedometer calibrator design which employs a $20 microchip, which can be programmed on your computer.

http://members.rennlist.com/tom86951...r%20Page1.html

http://members.rennlist.com/tom86951...rator-beta.gif

http://rennlist.com/forums/attachmen...arduino-n3.jpg

http://rennlist.com/forums/944-turbo...alibrator.html

Sending PM......