I know that changes in the sprockets can affect speedo readings and such, but mine has stock gearing.

It hit me today when I was riding home from work at an ok pace and all of the traffic around me is going about the same speed. My speedo said 90, but I am sure that we were all not doing 90 on the freeway. I have had a feeling it was off for a long time, but it is starting to bug me now.

How much is it off typicly? And about what speed does it start to be non acurrate? Indicated 70mph and traffic blows by me. Indicated 85-90 is brisk but not blowing traffic away. Indicated 120+ feels fast, but I just dont know how fast I am really going.

 

I followed my wife home the other day, and had her set the cruise on 60. This was a long straight flat area, so it would be constant. I showed 65 on my speedo.

I know hers is accurate, as I have recently timed it to make sure.

My cousin is an SRO, so I might run by his school, and ask him to clock me and see for sure.

 

it doesn't seem to be a constant percent. but mine with stock gearing at 70 in 5th gear was off by 6%. I changed gearing. then I bought a speedohealer - now its accurate - or at least very close - in the 50-90mph range.

 

Mine with stock gearing is about 5 mph fast at 60 as well. Years ago they used to have speedometer checks along side some open sections of non urban freeways here in California. I haven't seen one in I don't know how long.

 

I noticed before I was running a lower profile than stock. It was also worn. I checked against a car once at it read more than 10% high.

I think now with the new 55 series tire it's pretty accurate. I checked against a radar sign and it was very close.

 

I don't understand the speedometer. You'd think if the speedo is off say 3% at 60 mph., it would be off the same percentage at every other speed. Don't know why that isn't the case.

When I had stock sprockets and checked the speedo against roadside radar readouts, it always seemed spot on as far as I could tell considering that the VTR speedo is a bit of a rough, less than finely delineated instrument.

With the 43 tooth rear sprocket I know the speedo is about 4.5% optimistic compared to stock. At highway speeds I just figure I'm going a few mph slower than the readout.

 

RK1, pretty sure you're backwards.

Going from 41 to 43 teeth effectively lowers the gear ratio (numerically higher), thus your speedometer should be reading slower than you are actually going.

 

No, he's right. Shorter gear ratio means the engine and speedo sensor have to spin faster to maintain the same road speed.

 

Oops, I'm backwards.

 

Against my GPS, at 80mph, bike speedo is 6-7mph high in 6th gear. seams consistant down to about 60mph or so... Stock gearing...

LB

 

right on. Thats the answer I was looking for. By the way by cowtown do you mean Vacaville. If so hit me up for a ride. Just went yesterday up pleasants valley rd out to berryessa. It was great.

 

Stock many Hondas are 9-10% off. With a 15/43 sprocket change its 19% off. I enjoy cause it gives me constant math problems to solve while I'm riding. And I don't worry about the additional mileage cause I'm never selling my Superhawk.

 

(think- Ric Flare) WHOO!

Can I get an "AMEN" brother?