Triumphrat

Deskman

A bit trivial, but... my bonnie came with a kph speedo and I had it recently changed to the mph one so I could avoid doing the mental math each time I went through a 20, 30, 40, 50, 60, 70 mph zone.

Checking the indicated speed on the kph speedo to that on my SatNav, the results were pretty close to identical.

But when the mph one was installed, you guessed it, similar to some earlier threads the discrepency was 7~8 mph, ie: my speedo has to show 78mph to achieve 70 and ditto at lower levels give or take.

And of course the shop says that it can't or won't recalibrate the speedo as it falls within acceptable tolerances (acceptable to who?).

Just funny that the kph ones (based on a sample of one...) are accurate and the mph ones are way off!

But there you go.

Brian

PAAS

Probably can't in this case. It is very hard to dismantle these speedos without damaging the casing. As far as acceptability is concerned, UK law requires that speedos do not under read, but they are allowed to over read by up to 10%. So in the eyes of the law 7 to 8 mph over at 70 mph is just about acceptable bearing in mind satnavs are not 100% accurate and can be significantly off unless you're travelling in a straight line on a flat road. It's more strange that your kph speedo was accurate!

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Paul.

Herts. UK
Aubergine & White 05 T100 (865cc) with numerous mods.
(Previously Ducati Monster S4 and several UJMs)

357Bob

I don't know about the KPH speedos but look at the MPH. You will see the first 5 MPH is not there. The needle is setting at 5 MPH setting still. Just run 85 all the time. That is my sweet spot. About 4K.

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357Bob

FrankW

I've checked my KPH speedo against a gps and found it to about 5% fast.

i.e. Speedo reads 105KPH GPS shows 100KPH.

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I used to be paranoid, now I think they are out to get me
Grow old disgracefully and be an embarassment to your kids..

Staintune Exhaust, AI Removed, Main Jet (No Idea)

bonza

the KPH speedo on my bike is out by about 7-10%

when it reads 100KPH am actually doing about 90-93 KPH

both KPH and MPH speedos would have the same mechanical internals, it just the increments on the dial that are different, ie 60 MPH would be 100 KPH

speedos reading faster than what the bike is actually doing is some sort of safety factor and to cover the manufacturers arse if riders receive speeding fines due to a speedo error indicating a slower speed than the actual speed

however the odometer mechanicals would be different, as the pinion on the odo spindle would be smaller to accomodate a kilometer being shorter than a mile

BTW, the odometer appears very accurate

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2008 Black and White T100.
AI removed, Bafflectomy, 40/115/1 shim 2.75 turns, Pingel fuel valve, Monza petrol cap, Avon Roadriders, Triumph fabric saddle bags sometimes