Community Forums

poodles · 08-26-2012, 08:38 PM

Hi there,
I just put new tires on our mh, I went one size up and now I have about a 10% difference in speed and milage on the speedo. Speedo says 55, gps says 60. Also the mile markers are about 1/10th of a mile out.
Can I reprogram the speedo or do I have to have a tech change something on the sending unit?
Thanks in advance.

stik · 08-26-2012, 09:04 PM

Sorry I can't answer your question, but I am curious as to why you didn't just stay with the tire that was originally specified by the manufacturer?

Dutch Star Don · 08-26-2012, 10:12 PM

poodles.....I think???? they can reprogram your coach for different size tires.

Scarab0088 · 08-27-2012, 01:08 AM

Quote:

Originally Posted by poodles

Hi there,
I just put new tires on our mh, I went one size up and now I have about a 10% difference in speed and milage on the speedo. Speedo says 55, gps says 60. Also the mile markers are about 1/10th of a mile out.
Can I reprogram the speedo or do I have to have a tech change something on the sending unit?
Thanks in advance.

This is a common thing with the 4X4 crowd...
For modern rigs, the mod is in the ECU (not the sending unit). You can "flash" the ECU for tire size and some other things depending on the programmer you buy...or save the $$ to buy a programmer and have a shop do it for you.

On older rigs, the sending unit was replaced to modify the signal or, for really older rigs the tranny gear is changed to change the speed of the speedo cable.

Brigadoon · 08-27-2012, 05:18 PM

I did the same thing with my tires. When in the shop for routine maintenance, I asked the rv tech to reset the tire rpm's (rev per mile) to correct the speedo. He hooked up a laptop and went in and reset the rpm's to 517 for my tires. Speedo is accurate again. Look up your tires rpm prior to having it reset and you will be good to go.

poodles · 08-27-2012, 08:02 PM

Thank you all for the help. I will call the tech and see what he says.

Stik, I bought the larger tire because I believe the more side wall the more cushion you get out of the tire. I also went with Michelins and the ride is no comparison to the old Goodyears. Michelin have a softer sidewall and absorb more of the road bumps.

Expensive but I think it was a good investment.