speedometer

[trdbryan]

has anybody checked the accuracy of their speedometer, i have a 05 matrix TRD it has the factory 17" rims and tires.

According to my GPS when my speedometer is reading 120 i am actually doing 128, at 130 actuall speed is 140 km/hr

I was unsure how accurate the GPS was so i got my bro to pace me on the hwy with his car and 2 other cars at different times and it confermed that the GPS is accuate and that my matrix speedometer is way off.

Can or has anybody else checked the accuracy of their car with factory 17's.

Thanks

[bc toy]

that does seem like it is quite a bit off

[TRXR4KDS]

mine is off about 3-4% ie. when the speedo says 120 acyaully going 125 according to GPS and ScangaugeII.

[trdbryan]

thanks, going to try and figure out why mine is soo far off, and if the dealer can do anything about it

[trdbryan]

Been talking to dealer and Toyota Canada to try and get this issue resolved. I went out on the hwy with the service rep in their Sienna and there was a 10km/h diff between matrix and sienna. Matrix was at 100km/h and sienna at 110km/h and we would stay side by side. Dealer Looked at another TRD Matrix and found the same problem. They think it may be all the TRD's or all Matrix with 17's. I got the specs from Toyota for accuracy of speedo at 100 the max is 104.5km/h. I'm wondering if this is a reason why so many matrix owners claim that they cannot reach the rated fuel economy, all those times i though i was driving 120 i was actually doing 130.
Anybody else notice the same thing with their Matrix? I found that a GPS is pretty accurate.
Still trying to fight with Toyota Canada to look further into this issue.
Thanks

[edbso]

Got the snows on the XRS now but as I recall I would have been 1% or 2% under. Close enough to not think about it.

[cdencore]

I read somewhere that the Matrix speedometer is calibrated to the XR rim/tire combination which is 205/55/16 and no adjustments were made by Toyota for the XRS (or TRD) which has the 215/50/17 rim/tire combination.

If this is true, it may help to explain why your speedometer reading is out of whack. Would be really interested to hear other views on this.

[TRXR4KDS]

It vairies 4% between my 15's (exact with GPS) to 4% off with the stock 17's and my summer 18's. When I had 16" winters, it was off about 1%. Others have gotten different results than me though.