Speedo vs Tire Size Change

[Yogisan]

2010 CSC Cobra. Current tire size 205 60R 15. I want to change tire size to 205 70R 15 to increase gas mileage and top end speed. Will the larger tire fit the fender area and is there a way to adjust the speedo/odometer to correct for the change?

[FuzzyWuzHe]

Do a google search, there are charts on the net that give speedo changes for tire changes

[Yogisan]

Thanks. I already know that. What I am after is a way, programming or otherwise, of adjusting the speedo to a corrected readout. I don't want to get distracted by figuring out what the actual speed is every time I do a speed check which, around here, is pretty frequent. I did that for 5 years when I was in Europe with a mph speedo driving kph roads. It is a pain and a distraction.

[Gorilla]

I can not tell what make model is the base bike? Then you need to find out how that bike got its speed reading from. If it is electronic like a sensor then there are a couple of companies that sell a module that can be installed to modify that signal to get a accurate reading. If it mechanical then you are stuck with what you have as far as I know.

[chester]

Thanks. I already know that. What I am after is a way, programming or otherwise, of adjusting the speedo to a corrected readout. I don't want to get distracted by figuring out what the actual speed is every time I do a speed check which, around here, is pretty frequent. I did that for 5 years when I was in Europe with a mph speedo driving kph roads. It is a pain and a distraction.

If you have a late model GPS,that will give you the most accurate speed reading.

[Yogisan]

I can not tell what make model is the base bike? Then you need to find out how that bike got its speed reading from. If it is electronic like a sensor then there are a couple of companies that sell a module that can be installed to modify that signal to get a accurate reading. If it mechanical then you are stuck with what you have as far as I know.

Thanks. It's a 2010 Goldwing GL1800. I know about the modules you're talking about. I have a speedohealer on my Suzuki trike for just that reason. I'd rather make a correction using existing bike options, if any. I know the Cobra came with 3 wheel size options so I would think CSC woukd know how to make the change.

[Yogisan]

If you have a late model GPS,that will give you the most accurate speed reading.

I have a Garmin Zumo 660LM mounted on the trike. It does have a mph readout but the letters are real tiny and sun fade on the screen makes reading them difficult. I used a Zumo 550 on my Suzuki trike but those mph readout numbers were much larger.

[mhgoldwing]

Thanks. It's a 2010 Goldwing GL1800. I know about the modules you're talking about. I have a speedohealer on my Suzuki trike for just that reason. I'd rather make a correction using existing bike options, if any. I know the Cobra came with 3 wheel size options so I would think CSC woukd know how to make the change.

Check the diameter of two tires. If they are close then the change will be minimal. I know of no other way to correct since you don't want to use a speedhealer. Personally, I know my trike reads three miles per hour fast so it pretty easy to figure out.

[Yogisan]

Ok. I'm going to need a speedo correction device of some sort. That's answered.

Second part of the question. The tire I'm looking at has a 0.81" diameter increase. Does anyone know if there is going to be a clearance issue with the 2010 Cobra fenders?

[peteg59]

Speed differential between the sizes you call out Yogi, are minimal. Personally I wouldn't sweat it unless you speed a lot...

Check it out here:

https://tiresize.com/calculator/

To your second question, the 70 series tire is 1.6" taller than the 60 so unless you currently have at least a couple inches clearance around your tires to the underside of your fenders all the way around, you might have issues?

[chester]

I have a Garmin Zumo 660LM mounted on the trike. It does have a mph readout but the letters are real tiny and sun fade on the screen makes reading them difficult. I used a Zumo 550 on my Suzuki trike but those mph readout numbers were much larger.

procure the garmin 2797/7 inch screen,you'll be fine

[Yogisan]

I just finished replacing the 205/60R15 tires with 205/70R15's. It took a bit of effort to get the new tires mounted, especially the right side, but once the trike was off the jack the fender clearances are ok. At 60 speedo indication I'm actually doing 65 according to the gps, which was my main objective (higher speed at usual rpm's). I can definately feel the difference with the trike's performance and the ride is definately smoother. Next I will be installing a Speedo correction adapter so the speedo will be accurate.

[FuzzyWuzHe]

I just finished replacing the 205/60R15 tires with 205/70R15's. It took a bit of effort to get the new tires mounted, especially the right side, but once the trike was off the jack the fender clearances are ok. At 60 speedo indication I'm actually doing 65 according to the gps, which was my main objective (higher speed at usual rpm's). I can definately feel the difference with the trike's performance and the ride is definately smoother. Next I will be installing a Speedo correction adapter so the speedo will be accurate.

Dakota Digital makes a until for the GL1800

[Yogisan]

Thanks, but I already bought a 12oclockLabs unit. I just need to install it. That could be a bigger job than doing the tires. Lol.

[Lee H. Mann]

Thanks, but I already bought a 12oclockLabs unit. I just need to install it. That could be a bigger job than doing the tires. Lol.

Do you still have (in your avatar) the C-90 ???

[Yogisan]

Do you still have (in your avatar) the C-90 ???

No. I sold it about 2 months ago to a friend in northern MD. I gave him your contact info in case he needs it.

[pwhoever]

I have the Healtech speedohealer on my GL1800. It looks like it was a bit more expensive than the 12oclocklabs unit but it was plug and play. It plugged in behind the lower right side of shelter. And then there is an app that you can download to figure out what correction is needed. Not sure how the 12oclocklabs unit is installed but if it calls for splicing into wires, you might want to consider selling it and getting the speedohealer instead. I did end up cutting a small hole in bottom of the right side pocket for wiring harness but having speedohealer in left pocket is real convenient.

[Yogisan]

I have the Healtech speedohealer on my GL1800. It looks like it was a bit more expensive than the 12oclocklabs unit but it was plug and play. It plugged in behind the lower right side of shelter. And then there is an app that you can download to figure out what correction is needed. Not sure how the 12oclocklabs unit is installed but if it calls for splicing into wires, you might want to consider selling it and getting the speedohealer instead. I did end up cutting a small hole in bottom of the right side pocket for wiring harness but having speedohealer in left pocket is real convenient.

I installed a Speedohealer on my old trike so I'm familiar with it. The 12oclocklabs unit is also plug and play. The setup instructions appear to be pretty straight forward. It looks like the hardest part will be getting to the speed sensor connector to install it.