speedo accuracy

[Keen]

whats the accuracy like in terms of percentage error?

my bike's getting fixed and derestricted at the moment and the mechanic told me that on a test ride he got 100 out of it. He's also about 6'4" and 16 and a half stone! I'm wondering how accurate that is, cos with me on it (12 and a half stone) it must get speeds of over 100 on the clock?

[minesweeper]

fully derestricted it should reach 100mph with most people on the back, the nsr's speedo is quite accurate from what ive seen, plus remember he is a bike technician he will know exactly how to get the most out of the bike.

matt

[TiN]

But doesn't Keen have a Cagiva Planet?
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TiN
dotgems.net

[minesweeper]

i assumed he had an nsr! nah hes fuckign with yer

[Keen]

lol- I did hear that they only do 85 when derestricted unless you change the rear sprocket (the standard one is massive) but they haven't so the rumours must be wrong. The 0-60 should be pretty good as well with 43 teeth

[andrew]

[Kickstart]

Hi

Legally a speedo cannot read low and is allowed to read up to 10% high. Some seem to be more highly "tuned" than that

All thebest

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[WildGoose]

keith, are bikes tested before they are allowed into showrooms, by an independant organisation or something?

[moonym20]

i might be tredding a little out of my depth here but also remember (this mainy goes to electric speedo's) that as the tread on the tire wears down it will effect the accuracy of the speedo although this is probably so minor it isn't worth looking at. when i was doing my test and lessons on the CG125 my instructor always told me that the speedos were around 5mph out of the actual speed (thats -5mph)
another thing that pisses me off is that if you are more than 2mph over the limit you get shafted by the police... how the hell are you meant to know your speedo is bang accurate and doesn't have an error of a few mph?????........geeez

[McJamweasel]

You cant use the inaccurate speedo as an excuse. if the speedo is reading high and you get done for speeding then you would of thought that you were travelling faster than you were - therefore making things worse for yourslef. If the speedo was reading low then its illegal - therefore making things worse for yourself.
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BCF: Be yourself, just don't be an arse.

[chunkielad]

Plus the police have a general rule of allowing 10% of the speed limit plus 2mph before they book you as there's just too much paperwork other wise - saying that I only got a warning for 40 in a 30 zone - so it's really down to the cop at the time of the incident.

[Kickstart]

[batman]

speedos are usually well inaccurate
the thing is they are required to be accurate to an extent, so up to about 100 they tend to be pretty much correct
after this however they tend to be very inaccurate
a gsxr 600 will indicate 180+ but only does a true 169
a hayabusa will show 200+ but its true top is 189

[Doddmaster]

You're only saying that because you have an RS125 with one of the most highly-tuned speedos around!

[TiN]

[batman]

new fireblade does about 176
gsxr 600 does 169, 750 is as fast as a blade , 1000 does 181

[batman]

in case your wonderin where i got this, august performance bikes test on ultimate track bike
heres the tested speeds:
2002 honda fireblade 172.2 mph(indicated 187) but shagged tyres blamed for it not being as fast as it may have
2002 gsxr600 169.8 mph(indicated 186)
rsv mille 173.8mph(indicated 173) so accurate there
also yes the rs125 lies it arse off, says its doin 115 when its only doin 100 or so, my mates fzr 250 showed 110 tho and i was goin beside him and my speedo read 95!! they all lie :P

[TiN]

OK, fair enough mate

It's funny how the Aprilia speedo (ok, it's not an RS125) was the only that actually read true?
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TiN
dotgems.net

[batman]

yeah they said the same thing, usually italian bikes tend to lie a lot on speedos!