Triumphrat

SevenMonkeys

I got a 2005 Bonnie two years ago and the speedo has read about 10% high since I got it.

Is there a simple way to adjust the speedo?

Casey

SCbonneville

Since there are no "easy adjustments, the two ways to easily deal with it is to either get a front tire that has a larger overall diameter (they're not all the same, even if they have the same size designation) such as a Metzler ME880 (great tire btw). Or you can source a Thruxton speedometer drive from a MC salvage yard such as Pinwall. They are set up for an 18" wheel and that will correct things by turning less rpms per mile...


I run ME880 fronts, stock size and they give me just about dead on readings when I go past those "you speed is" radar stations...

bheezy27403

I bet it's flashing red when it tells you your speed ;}

ozbon

Yeah!!, Ride 10% slower!!!.......

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Daz, the cane toad.

SevenMonkeys

I put a Metzler on the rear, but the BattleAx in front hasn't needed replacing. I'll probably put a Metzler up front when the time comes.

Thanks.

zelatore

Not having a Bonnie myself, is the speedo mechanical or electronic? If it's electronic, a speedo healer should do the trick.

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Don
'06 Speed Triple
'96 Adventurer Cafe Racer
and a bunch of other stuff
If everything seems under control, you're just not going fast enough - Mario Andretti

Baltobonneville

Mechanical up to 2009 or thereabouts.

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Marty
2005 Bonneville Blue 790cc, AI removed, Staintunes RC, Uni filter, no snorkel, 118/40/NBZT "Thruxton" needles/1 shim/3 turns, tachometer, Ikon 7610s, Ricor Intiminators, Dunlop GT501s, D9 gauge panel.

threewheelsuk

Hello

UK law (and probably elsewhere) allows for a 10% speedo error (reading high) to allow for different tyre sizes and wear and bragging rights or use a sat nav.

Regards

Barry

Bron-Yr-Aur

You can't even really trust the nav systems either. My Garmin reads up to 4 mph off sometimes. It also varies depending on if you're on flat land or in the hills. Long story short, are you sure the readings are off?

I thought that my '06 was off 4-5 mph, but after doing my own calculations, I realized with my stock tire, at 60 mph it was only 1-2 mph wrong.

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(The artist formerly known as kreemsicleT100)

"Ya can't have 'no' in your heart. Life's a garden. Dig it." - Joe Dirt
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Bron-Yr-Aur Garage

SevenMonkeys

I knew it was not correct just based on what traffic around me was doing. I'd be doing 15 over in a 45 zone and still getting passed :-)

So I used a simple speedo app for Android on a long straight stretch and held a steady speed.

The speed given by GPS is pretty accurate if held steady for say ten seconds. It has to smooth your velocity a bit as it calculates it. It could be off by couple percent, but not ten.

I'm used to the speed being off, but I hate that the odometer has the same error. And all my mpg calculations have a fudge factor.