Is there a way to calibrate a speedo?

[NATEO]

I was riding around, and it seemed like traffic was going considerably faster than when I am in my car...I started wondering if my speedo was wrong, becasue it said we were going 55 to 60 in a 40 zone, where the cops are really tight...I know we dont go that fast there... so I finally pass one of those police things that tell you how fast you are going, and it say about 35. I look down and my speedo says 45.... is there a way to fix that? I have never known highway traffic (even on 95) to be going 80+ in the slow lane:-D

[t3rmin]

I'd like to know this also. The PO put on a larger rear sprocket so I know the speedo will be off. My plan at this point was to take my GPS (which shows MPH) with me, see what the discrepancy was, and mentally account for it in the future.

[lord1234]

suzuki speedos are NOTORIOUS for being off.

[Billyboy]

The size of the rear sprocket has NOTHING to do with the speedo and everything to do with engine RPM.

The speedo runs off a hub in the FRONT wheel. Tire size will affect it.

[DimitriT]

I bungied a small handheld GPS over the tach and went for a ride to see how accurate the speedo on the 550 was. It wasn't too far off.

I think there's an article on this forum which talked about adjusting the tension on the spring which controls the needle. I think he used a handheld drill (max RPM), read out the reading on a known working speedo and then used the same drill to adjust the wrong one.

[8trackmind]

The size of the rear sprocket has NOTHING to do with the speedo and everything to do with engine RPM.
The speedo runs off a hub in the FRONT wheel. Tire size will affect it.

What Billy said, and...Count on the speedo being at least 5 to 10 MPH faster than what you're going.

[t3rmin]

The size of the rear sprocket has NOTHING to do with the speedo and everything to do with engine RPM.

The speedo runs off a hub in the FRONT wheel. Tire size will affect it.

Duh. You're absolutely right of course. Thanks.

[Billyboy]

Count on the speedo being at least 5 to 10 MPH faster than what you're going.

I've got a 100/90 tire on the front. It seems that it evens out the speedo nicely.

[GSstiny]

You can figure at least a 10% error all the time. If you want to get technical, write down your sprocket ratio, trans ratios, and rear tire circumference, and you can calculate how fast youll be going at any RPM.

[NATEO]

You can figure at least a 10% error all the time. If you want to get technical, write down your sprocket ratio, trans ratios, and rear tire circumference, and you can calculate how fast youll be going at any RPM.

ummm....yeah. not worth THAT much to me...I will just make a mental note... or have someone drive a cage at a set speed, and I will match it and see what my speedo says... that wouldnt be too bad...

or is there an aftermarket gauge I can slap on there?

[Einar J Skog]

Hi

I mounted a bicycle speedo on the handlebar.Just put in the numbers for front wheel circumference .Magnet on the side of wheel rim ,and sender on front fork.
It is accurate up to 300 km .Or you can set it to miles.
(Sigma sport 800)It has peed-topspeed-averagespeed-triplength-
triptime(moving)totallength- clock.

My speedo shows 80 km when I drive in 73 km...