People running bigger tires, are you just not recalibrating your speedo?

Awesome. Thanks for the info man!

 

Newbie question.. So I understand that having larger tires will offset the speedometer but is this the reason why my truck shifts early as well? Will buying the hypertech inline calibrator adjust not only the speedometer but the tranny shift points as well?

 

On both my Jeep and Tacoma I went up in size - up to 31's on my jeep, 33's on the Taco, neither one seemed to *need* recalibration, I never regeared (and still haven't on the Taco). I've sort of self-calibrated with multiple speed checks around the area, it's spot on at 25mph, and I've gotten them up to 50, which it's still spot on. The case was the same on my Jeep, so I don't think there's as huge of a difference as we think it is.

 

Same here......the faster you go, the more it is off. At low speed around town(30mph or less), it's only off a few mph. Most smart phones have speed/gps calculator apps. I use one from time to time.

 

Hey, no worries about newbie questions. We are all here to help! And in answer to your question, yes, that is why your transmission shifts differently. It still assumes that your tires are a factory size. The shift pattern is designed around this.

Your second question is VERY important. The hypertech calibrator only corrects the information going to your cluster. The automatic transmissions and ABS system will STILL go by the wheel speed sensors, which technically will be incorrect (albeit how FAR incorrect is based on how different the tire size is) So shift points and ABS operation will be affected still.

I still don't see why Toyota does not do like GM does. A technician at the dealership working on trucks can use the Tech2 scan tool to program the ABS computer to the new tire size, and this corrects the ABS system, transmission shifting points, as well as the speedometer and odometer. GM's reprogramming will also allow for up to a 35 inch tire size. Toyota should adapt that concept as well.