Firestorm Speedo vs GPS "TRUE" Speed - THE RESULTS

Tempest · Post by **Tempest** » Thu Aug 10, 2006 8:26 pm

I've seen a few post items on this subject, so I thought some may find the following interesting.

I just went out of my Firestorm with my TomTom Go SatNav fitted (my own custom mount).

I did all "INDICATED" speeds from 10mph to 90mph (the latter on a private road!) ahem.

Here are the actual figures.

The 1st figure is the Speedo Indicated Figure.
The 2nd figure is the SatNav Figure.

I double tested these on 2 different roads, just in case differetn directions made any GPS variations.

Anyway..............

Indicated 10mph = Actual 8mph

Indicated 20mph = Actual 18mph

Indicated 30mph = Actual 26mph

Indicated 40mph = Actual 36mph

Indicated 50mph = Actual 45mph

Indicated 60mph = Actual 54mph

Indicated 70mph = Actual 64mph

Indicated 80mph = Actual 72mph

Indicated 90mph = Actual 82mph

As you can see, by the time you get to 100, I guess you could be around 10mph out.
I'm quite supprised. I would have guessed say 3 or 4 mph out at 80 but not 8 !!!!

I'm thinking I'm going to make a stick on curved thin dial, custom printed and put on the speedo, to make it 100% accurate.

Thoughts on my findings anyone?

Oh yes, in case you are wondering. I did the speed run for a while to let the figures settle down, so I'm quite confident in their accuracy.

Fireman on a Storm · Post by **Fireman on a Storm** » Thu Aug 10, 2006 8:50 pm

Am I right that you have bought Tony's storm?

If I am didn't Tony fit a 15t front sprocket?

tony.wilde1 · Post by **tony.wilde1** » Thu Aug 10, 2006 9:00 pm

i fitted a standard sprocket last time i changed them

Fireman on a Storm · Post by **Fireman on a Storm** » Thu Aug 10, 2006 9:01 pm

Tempest · Post by **Tempest** » Thu Aug 10, 2006 9:03 pm

Fireman on a Storm wrote:Am I right that you have bought Tony's storm?

If I am didn't Tony fit a 15t front sprocket?

Yes, I have Tony's Storm.

He had a new chain and sprocket set fitted fairly recently, but I've no idea about tooth numbers.

It does accelerate well though

Will have to ask him.

How many teeth do both sprockets normally have?

Tempest · Post by **Tempest** » Thu Aug 10, 2006 9:04 pm

tony.wilde1 wrote:i fitted a standard sprocket last time i changed them

Beat me to it

Must say I'm impressed by the pulling power (as you said it's a standard tooth sprocket)

If you'd have said that it had a smaller front and larger rear for extra acceleration (but lower top end) I'd have quite believed it.

cupasoop · Post by **cupasoop** » Thu Aug 10, 2006 9:10 pm

These numbers dont sound too far off, speedos always read low. About 10% sounds right.

Tempest · Post by **Tempest** » Thu Aug 10, 2006 9:22 pm

cupasoop wrote:These numbers dont sound too far off, speedos always read low. About 10% sounds right.

Indeed, if you do the Maths, it is pretty much exactly 10% down on REAL speeds.

I still fancy being clever and making a custom paper ring (laminating it) and putting on the speedo.

If I do I'll put a photo up on here.

Post by **kevg** » Fri Aug 11, 2006 9:58 am

i'd agree with the findings, i think mine may be farther out though, or my mates are, when i'm out with them they say they are at 95, and i'm at 110, so if thier speedos are 10% out, where does that leave mine, lol.

Tempest · Post by **Tempest** » Sat Aug 12, 2006 1:44 pm

Where does the speedo actually take it's drive from?

I assume it is a mechanical linkage (or are we electric?)

Wonder if there's anything you could do (to the speedo or the linkage) to make it read say 8 or 9% higher and give a more accurate speed?

Fireman on a Storm · Post by **Fireman on a Storm** » Sat Aug 12, 2006 2:04 pm

electric! There is an electical sensor on the output of the gear box

There is an plug in electric gaget you can buy. I am sure somone on here knows what it's called.

chaz · Post by **chaz** » Sat Aug 12, 2006 2:15 pm

if memory serves me, the law allows you to be 10% over, to allow for such errors. If you wanted to be really pedantic fitting a low profile tyre or even a smaller (or bigger) wheel will upset readings and would mean a recalibration.
I suppose, by the time you have worn the front tyre down you could be 1 or 2 mph down anyway. anyone care to do the maths, radius 3mm smaller (average tread wear)..
no wheres that 16" blade wheel

Tempest · Post by **Tempest** » Sat Aug 12, 2006 2:55 pm

I've found this:

http://www.cartestsoftware.com/fz1/spee ... ation.html

And this:

http://www.speedohealer.com/eng/intro.htm

And this:

http://www.cartestsoftware.com/fz1/yell ... ation.html

I'd like one, but I'm not paying those prices when I can make an overlay for the speedo for prety much nothing.

Shame they are not cheaper, otherwise I'd get one for every car and bike I have

Tempest · Post by **Tempest** » Sat Aug 12, 2006 3:03 pm

SpeedoHealer sounds the best and their calculator says I need to adjust by 8.9% and tells you the buttons to get that correction (Very impressive)

And one for our bikes also:

Honda-I plug-n-go kit: Fits ALL Honda motorcycles with electronic speedometer, such as:
CBR600F3, CBR600F4, CBR600F4i, CBR600FS, CBR600RR (2004 and earlier), CBR900RR Fireblade, CBR929RR, CBR954RR, CBR1100XX Blackbird, X11, CB600, CB900 Hornet, CB1300, CBF250, CBF500, CBF600, GoldWing GL1800, VFR750, VFR800, VTR1000F FireStorm, VTR1000 SP-1, SP-2, RC51, ST1300, XL1000 Varadero (2004 and earlier), VT, VTX1800 (2003 and earlier), etc..

If my maths are correct. I think this is Â£56 UK Pounds Delivered.

Tempest · Post by **Tempest** » Sun Aug 13, 2006 12:20 pm

Ok then..........

Having read all about SpeedoHealer it sounds great, and you can correct your speedo for about Â£60.

Or, how about the method I came up with.

Cost you NOTHING apart from some time

Worked out all the angles of the original marks (Into Degrees) then used photoshop to re-draw the original marks, then offset them by the speedo error and re-draw them.

Printed, cut out and laminated the curve.
few bits of double sided tape and job done.

I've only done 0 - 100 at the moment as I may change sprockets (which will need a modification) and I may put 5mph markers in also.

So, saved Â£60

Could do a different colour paper, or change the shape, or do anything really.

Easier to read in white than the original black.

Any comments?