JKOwners Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
So I have new tire on my hew 2017 wrangler sport and I got the dealer to recalibrate the speedometer and everything for me using flashcal. My question is the flashcal lets you calibrate tire size 32.5 - 32.75 and my tires are 32.6. Should the computer not be programmed for 32.75? At 40mph and above the speedometer is off.


Sent from my iPhone using Tapatalk
 

·
Gunnery Sergeant USMC (ret)
Joined
·
22,098 Posts
Exactly 32.6? Did you measure them while on the jeep?

The difference between a 32.6 tire and a 32.5 program is .2 miles per hour off. Do you think your speedometer is actually spot on at say 65 mph?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #4
If speedometer reads 65 I am actually under that, maybe 63. At 70 I was actually going 67 according to traffic speed signs.


Sent from my iPhone using Tapatalk
 

·
Super Moderator
Joined
·
6,239 Posts
just use your flashcal and set it to 32.50psi or 32.25psi settings and test. Don't use stupid street-alert detectors for speed measurement , use google maps or some other phone accelerometer app like TorquePro to determine your true speed. Ya have to play with the settings a bit on your superchips tuner to get it right ...air pressure in tire can make a difference , environment can , tarmac temp can...you'll find sweet spot but I wouldn't let dealer play with my tuner , heh. :jeep2:
 

·
Gunnery Sergeant USMC (ret)
Joined
·
22,098 Posts
I know it's off at 65 for sure. I think by 2 or 3 mph.


Sent from my iPhone using Tapatalk
If speedometer reads 65 I am actually under that, maybe 63. At 70 I was actually going 67 according to traffic speed signs.


Sent from my iPhone using Tapatalk
2 replies and you didn't even answer the question I asked.

How accurate do you think the traffic speed signs are?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
I know it's off at 65 for sure. I think by 2 or 3 mph.


Sent from my iPhone using Tapatalk


No I didn't measure them I went off manufacturers specs for the tires.
As far as speed I also used a speedometer app on my phone that registered the same difference as the highway signs. The only reason I mentioned them is I drove 1500 miles and passed 8 of them that all read the same numbers. They were all at least 100 miles or more apart.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
45 Posts
Take a measurement of you tires.

You have to measure the tires. Then put that measurement in the procal. When I had my 33's, i put 33 in the procal and my speedo was off ( I didn't know any better at the time). Once i properly measured my tires, and put that number in the procal, the speedo was correct.
 

·
Gunnery Sergeant USMC (ret)
Joined
·
22,098 Posts
You really need to measure them while on the jeep aired to normal pressure to get the exact measurement.
 

·
Registered
Joined
·
1,173 Posts
I measured center hub to ground, times two, entered that figure into my AEV ProCal. Speedo is spot on at 70mph when compared to GPS.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #11
Just measured 31.25. Now to reprogram and see how it goes. Thank you all!! New to this tire and computer thing. Didn't have it on my 91 wrangler (which I still didn't know to much about).


Sent from my iPhone using Tapatalk
 
1 - 13 of 13 Posts
Top