Speedometer reading inaccuracy

Kruz99

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I noticed the inaccuracy of the speedometer vs the readings on GPS. It's actually reads 20km/hr faster than what it's suppose to be. Seconded confirmed by my mate riding side by side.
Any ways to improve it?
I've heard to switch to a 1150RT speedometer drive.
Any suggestions?
 
Mine was the same, I tried the speedo drive off a 17" wheel and it ran too slow by about 12%.
Best compromise is the speedo drive off an RT fitted with an 18" front wheel.
 
An alternative is to acquire a good quality bicycle computer (not wireless) with a clear display. A small rare earth magnet (eBay, or I have several spare ones) can be epoxied to the wheel arch in place of the supplied one if you don't have spokes. If you do have spokes the r/e magnet just attaches to the supplied one

The sensor can be fitted to a small piece of credit card which in turn is fixed to a leg

This setup allows greater clearance between sensor and magnet and the flexible mounting allows some give if you pick up any foreign objects such as mud or road tar

Before purchase check that the wire is long enough to reach up the suspension leg into the cockpit area
 
Can't you just use the reading off the GPS if it concerns you that much otherwise we might get into how to recalibrate it to account for tread wear.
 
I've calibrated my head rather than the speedo - I know I'm safe to +5mph from 30 upwards. If I'm super concerned about making maximum (legal) progress I use the satnav (assuming I have it fitted).
 
:rob:rob:rob:rob:rob:rob:rob

I did the same mod as Bob and totally agree with all his comments. :thumb

It will, however, make it appear as though your fuel consumption has increased.:eek:

Mike
 
To be legal the speedo shouldn't read more than 10% over. If you swap to a 2.6 ratio drive that is 13% lower which may make your speedo under read. Potentially expensive with speeding tickets and points. I fitted the 2.875 ratio which is about 4% lower.

Look here:- Motorworks

Part No. WHA06532 = 4% lower
Part No. WHA50348 = 13% lower

Wheel out, undo speedo cable, swap drive, attach cable to new drive, wheel back in, jobs a good-un in 15 minutes.

You will be travelling faster all the time so you will use more fuel. The odometer will record less miles for a given trip so will tell you that your fuel consumption is even worse:D
 
Can't resist!

Packer said:
To be legal the speedo shouldn't read more than 10% over. If you swap to a 2.6 ratio drive that is 13% lower which may make your speedo under read. Potentially expensive with speeding tickets and points. I fitted the 2.875 ratio which is about 4% lower.

Look here:- Motorworks

Part No. WHA06532 = 4% lower
Part No. WHA50348 = 13% lower

Wheel out, undo speedo cable, swap drive, attach cable to new drive, wheel back in, jobs a good-un in 15 minutes.

You will be travelling faster all the time so you will use more fuel. The odometer will record less miles for a given trip so will tell you that your fuel consumption is even worse:D
Click to expand...

Actually it's not more than 10% PLUS 4 kph! There are huge penalties for any manufacturer making a vehicle with an under reading speedo and a 10% plus 4 kph over reading allowance. They make them so they over read, that way they have no risk of incurring the penalties. The later electronic speedos are more accurate than the cable driven type but still of course err on the side of safety (for the manufacturers that is).

Your pedant in exile.

John
 
Bob Southgate said:
The speedo drive from the R1150R is the answer to the inaccurate speedo on the 1150. When I fitted one to my old 1150GS it brought the accuracy down from +10% to +3%. It has a 2.6 to 1 ratio (standard GS is 3.0 to 1).

http://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=speedo+drive
Click to expand...

Trying to rely on my memory from 8 years ago can be dangerous. :D It was the 2.875 ratio one I used, not the 2.6. At an indicated 118mph on the speedo the GPS was showing 115. The odometer was also much more accurate.
 
Bob Southgate said:
Trying to rely on my memory from 8 years ago can be dangerous. :D It was the 2.875 ratio one I used, not the 2.6. At an indicated 118mph on the speedo the GPS was showing 115. The odometer was also much more accurate.
Click to expand...

Just checked my records.

The speedo drive I fitted to my 1150GS was from an 1100R.

When checking it with the sat nav it was very accurate, but never under-read.

Mike
 
Another vote ...

... for the 2.6 :thumb I've had the same one fitted on both my 1100 and 1150; brings the speedo down to about 3mph above the GPS at 70mph and so remains legal :D
 
sockpuppet said:
Can't you just use the reading off the GPS if it concerns you that much otherwise we might get into how to recalibrate it to account for tread wear.
Click to expand...

Well, I don't have my GPS permanently fitted on my GS unless am on a road trip, Singapore is too small of an island city to be in need of GPS.
 
Packer said:
To be legal the speedo shouldn't read more than 10% over. If you swap to a 2.6 ratio drive that is 13% lower which may make your speedo under read. Potentially expensive with speeding tickets and points. I fitted the 2.875 ratio which is about 4% lower.

Look here:- Motorworks

Part No. WHA06532 = 4% lower
Part No. WHA50348 = 13% lower

Wheel out, undo speedo cable, swap drive, attach cable to new drive, wheel back in, jobs a good-un in 15 minutes.

You will be travelling faster all the time so you will use more fuel. The odometer will record less miles for a given trip so will tell you that your fuel consumption is even worse:D
Click to expand...

My speedo reads more than 20%! That's more than the standard 1150GS readings.

Great info peeps!
 
Interestingly I changed my 1150 last year for a new 1200 (bloody mistake) but after 2 foreign trips including two runs down to Austria using the same route as I did on the 1150 it is interesting to see that whereas the 1200 /gps says it is 820 miles the 1150 always registered it on the odometer as 910 to 920 miles,

So does that mean that my 1150 didn't have 35,000 miles on the clock but really had only 30,000 ???
 
Neil W said:
Interestingly I changed my 1150 last year for a new 1200 (bloody mistake) but after 2 foreign trips including two runs down to Austria using the same route as I did on the 1150 it is interesting to see that whereas the 1200 /gps says it is 820 miles the 1150 always registered it on the odometer as 910 to 920 miles,

So does that mean that my 1150 didn't have 35,000 miles on the clock but really had only 30,000 ???
Click to expand...
Yes

Pekka
:rolleyes::rolleyes::rolleyes:
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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