For street 'n strip purposes, I changed the factory tires on my 2011
Ram ST RCSB from the stock 265/70R17's to new 275/55R17's on the front staggared with new 305/45R18's on the rear. Both of the new tire sizes are within 1/10" in diameter at slightly under 29" (stock diameter was 31.6"). Obviously, I needed to correct my ECU for the new tire height.
A call to my dealer revealed that they could flash the ECU for about $95. I thought damnnn, that ain't cheap for 5 minutes work. I remembered that the Hypertech Speedo Calibrator
was mentioned in a thread on this forum and one of the posters said it worked on 2011 models...! A quick visit to Hypertech's web site confirmed that information and I ordered one. It cost twice what the dealer wanted to flash the ECU but at least I would own it. It can read and erase codes, change gear ratios, calibrate the speedometer, and return to factory settings anytime. Possible tire sizes range from 22.5" to 44" in .25" increments. It's not a real tuner
but it's as close as I can get for now.
The package arrived by UPS and included a USB cable, an OBD port cable, a CD that contains both instructions and an installable computer application for updating the Hypertech firmware online. I installed the app, ran it, and was promptly informed that I had the latest firmware. Cool! I then read the CD instructions which specified that no electrical device should be allowed to operate (draw current from the battery) while the Hypertech unit was connected to the OBD II port (apparently it is VERY voltage sensitive). I pulled the fuse for the sat radio, closed the door, fastened the seat belt, turned the key to "On" and connected the Hypertech to the OBD port under the dash. The unit's display came alive with checks and easy instructions. It said there was one DTC (data trouble code) which I looked up at an online OBD II website. It was..."Failure to communicate with radio"
. Well, of course, I just disconnected the radio fuse! More coolness--it works!
Happy that it all seemed to be connecting properly, I followed the simple screen prompts and entered my new tire size which was flash-written to the ECU without any issues. I am impressed that the unit does what Hypertech claims it does.
I rate it A+.