180/55/17 on the ST1300

[Turtle]

I have a question on having a 180/55/17 PR3 fitted to the 1300

Anyone had one on?

Speedo Difference ?

I have one in the shed from my experiment days on the 1100 so was thinking about putting on the 1300
as I only took it off for the run to Middleton 2013 with fresh rubber go that trip

Turtle

[Brock]

Is that the ST1300 rear, if a different size on the rear, then the speedo will be different

[Turtle]

St1300 rim width 5.0

180/55/17 recommended for 5.5

Not much in it

[saaz]

Tipsy had a 180/55 on the ST1100 and the ST13 seems to have more space, and it takes a 170 to start with.

[JC]

Is that the ST1300 rear, if a different size on the rear, then the speedo will be different

The slightly smaller OD will make the speedo more inaccurate, as my speedo reads about 10% high, when compared to each of my Garmin ZUMO GPS units.

Use a GPS to get a real life comparison and then just remember what it indicates versus what is real.

[Brock]

While thats true, the odometer will then be out.. Nasty little conundrum that.

[West Aussie Glen]

Is that the ST1300 rear, if a different size on the rear, then the speedo will be different

The slightly smaller OD will make the speedo more accurate, as my speedo reads about 10% high, when compared to each of my Garmin ZUMO GPS units.

I thought the speed sensor is on the front wheel, if so nothing you do to the back wheel will effect the speedo.

If it is on the back wheel then a smaller OD tyre will make the speedo read higher still than the actual speed. Bike travels a shorter distance for every revolution of the wheel.

[West Aussie Glen]

Smaller OD back tyre will mean higher engine revs for the same road speed.

[Brock]

1300 Speed sensor is off the engine out put some where, not the front wheel. The front wheel is the 1100.

[West Aussie Glen]

1300 Speed sensor is off the engine out put some where, not the front wheel. The front wheel is the 1100.

Good, so it is a function of rear wheel speed. Must be at or after the gearbox output. Therefore smaller rear wheel means speedo will read even higher than it does now.

[Williamson]

..... means speedo will read even higher than it does now.

That would be a problem.  My ST1300's speedo reads around 10% higher than the GPS.  Is this a common problem with the ST13?

[StinkyPete]

..... means speedo will read even higher than it does now.

That would be a problem.  My ST1300's speedo reads around 10% higher than the GPS.  Is this a common problem with the ST13?

I have a standard 170/60 x17 on the rear.   At 110 km/h on the GPS, my speedo reads 118 km/h

[Abe]

..... means speedo will read even higher than it does now.

That would be a problem.  My ST1300's speedo reads around 10% higher than the GPS.  Is this a common problem with the ST13?

I have a standard 170/60 x17 on the rear.   At 110 km/h on the GPS, my speedo reads 118 km/h

X2 for what it's worth.

[Brock]

Its not an ST problem, it applies to all vehicles. If you change the size/diameter of the tyres then the speed indication will be altered.

The fix is a White ST, the speedo is calibrated... Unless of course the tyre is replaced with a non standard one.

 

[Nigel]

Its not an ST problem, it applies to all vehicles. If you change the size/diameter of the tyres then the speed indication will be altered.

The fix is a White ST, the speedo is calibrated... Unless of course the tyre is replaced with a non standard one.

 

Perfectly put..............................

[Abe]

Its not an ST problem, it applies to all vehicles. If you change the size/diameter of the tyres then the speed indication will be altered.

The fix is a White ST, the speedo is calibrated... Unless of course the tyre is replaced with a non standard one.

 

Perfectly put..............................

Absolutely correct, and over here (east coast) they have a calibration sticker (ex Police cycles) on the underside of the pie warmer (offside) stating the last time the speedo was calibrated.  A member in Bathurst NSW would be able to confirm this for us (Downunder where are you  )

[winston66]

Hi everyone,
Winston66, here.
I have a Kumho 205/50-ZR17 fitted to my 2003 1300, the rolling circumference is so close to the  the circumference of the origional OEM fitted specification tire that there is no appreciable  difference to the speedometer operation.
I can only suggest that if possible check the rolling circumferences of your original  tire and then compare that to the one that you intend to replace it with.
With some simple math you will then be able to see what difference if any there is between them.
As far as I am concerned my speedo is pretty accurate because at 5000 rpm in 5th.gear the bike is going quite fast enough for me at somewhere around 150 Klm. per hour.
Cheers, Winston66, northampton

              

[Williamson]

..... With some simple math you will then be able to see what difference if any there is between them.....

Or you could use this tyre size calculator:  http://tire-size-conversion.com/tire-size-comparison/

I ran a comparison on the 170/70 17 and the 205/50 17 and came up with this:


How does this compare with the maths?

[winston66]

Hi Williamson,

That is a very good calculator and a quick result from you, Thanks for that

With that extra 5% difference I guess that there is even less of a chance that I will ever have to make a donation to the police retirement fund .(If I drive by the speedo)
That suits me fine.
and I guess that the STeed will not need servicing as often because I have a small amount of spare mileage or allowance that I can make up.
cheers Winston66

[Williamson]

..... make a donation to the police retirement fund .(If I drive by the speedo)
That suits me fine......

The error in Mrs W's 2006 Mazda6 is just under 10%, my 2012 Ford Ranger is around 10% and the previous bike, a 2003 CB1300 was also 10%.  The only vehicle I've had recently, since I've been checking speedo against GPS, that had a reasonably accurate speedo was a 2006 Falcon ute.  This was consistently reading around 1km/h less than the GPS.  Because of these errors I generally don't drive or ride by the vehicle's speedo, but by the GPS. 

I've not had a speeding fine since I've been using the GPS over the past eight years (touch wood).  Not that I that had many in the previous 30 plus years (only three), but we won't discuss the five or six years before that.

That suits me fine too!

[West Aussie Glen]

..... means speedo will read even higher than it does now.

That would be a problem.  My ST1300's speedo reads around 10% higher than the GPS.  Is this a common problem with the ST13?

By a "common problem with the ST1300" I assume you mean that all ST1300 Speedo's read high. IF so, yes it is a common problem, your 118 speedo reading for a GPS reading of 110 seems about standard.
You can buy one of these  http://www.healtech-electronics.com/products/sh/ to fix that problem.
Unfortunately I am not sure if it just adjusts the speed reading or also changes the speedometer and I don't know if the ST1300 speedometer reads high like the speedo does, I would think so, does anybody know?
Most cars and apparently the ST1300 derive their speed from the speed of the drive wheels so change the diameter of the drive wheels and you chance the speed of the vehicle compared to it's speedo reading.
Apparently the ST110 and certainly my GL 500 take the speed from the front wheel so changing the diameter of the rear wheel only changes your speed in relation to your engine revs. 

[Brock]

The digital speedos, are set to over read so that you cant blame the manufacturer for exceeding the speed limit, however the odometer (distance meter) is accurate. By putting in a Speedo healer, you are altering the speed signal from the speed sensor to have the speedo read correctly. It stays fitted to the vehicle. The healer also has the effect of changing the distance covered as well. on computerised vehicles, this will also affect fuel ecconomy and fuel range readings as well.

This means, that if you bring your speed reading down to match the GPS, the distance covered will go down and produce an apparent loss of economy..

For the far riders, it will bugger up distances covered on the 1600 etc, meaning you would go for longer to try make the distance. Wish there was an easy way to re program the vehicle computer..

[saaz]

My car is accurate, but you can get into the ECU and alter all sorts of things, including any changes to the drive train (wheels, tyres, diff ratios etc etc)  Bike ECUs seem to be relatively crude and locked.

[JC]

Hi everyone,
Winston66, here.
I have a Kumho 205/50-ZR17 fitted to my 2003 1300, the rolling circumference is so close to the  the circumference of the origional OEM fitted specification tire that there is no appreciable  difference to the speedometer operation.

Cheers, Winston66, northampton

              

Does this mean that a 205/50 will also fit into the 2010 models, or did something change for 2004?

It seems that ADR 18/00 sets the rules for speedos and odometers. The latest version I can find is 2006. http://www.comlaw.gov.au/Details/F2007C00025/Download

Indicated speed can be +/- 10%
Indicated distance can be +/- 4%

[West Aussie Glen]

JC do you realise that Winstons Kumho is a car tyre?

That -10% on the speed is amazing , how can that be allowed when you can be booked for +5% on the speed limit?
Would be interesting in court if your car speedo does read -10% but as mentioned above I think most manufacturers paly it safe by having their speedos read high.