Tire Size & Speedo Error
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Joined: Dec 2000
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Tire Size & Speedo Error
I am running 215/70R14 tires on the aerostar. The decal inside the door says I should be running 215/75R14. When I am going below highway speeds my speedometer and gps are fairly close but as I go faster they start to differ. When the aerostar speedo reads 75mph, my gps only reads 70mph. That kinda shows you the error you will get with smaller tires. Curious as to what size tires you folks are running.
Robert
95 Aerostar Cargo Van 3.0L
94 Impala SS
74 Datsun 260Z 2+2
Robert
95 Aerostar Cargo Van 3.0L
94 Impala SS
74 Datsun 260Z 2+2
Senior User
Joined: Feb 2000
Posts: 145
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Tire Size & Speedo Error
My 88 Aerostar purchase new is equipped with the standard 215-70x14 tires and the speedometer has always read low. For example, a true 75mph is 78mph on the speedo. A true 65mph is about 68-1/2 on the speedo. This is measured by the 1/4 mile making on the interstates used by the Iowa State Patrol when using their aircraft to measure vehicle ground speed.
-Mark
-Mark
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Joined: Aug 2000
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Tire Size & Speedo Error
My '93 Aerostar is equipped with the 215/75-14 tires (as shown on decal). Most towns in my area have a radar on their main street that will show your speed on a large display. According to the radar, my speedo reading is nearly 100% correct.
Tom Ucen
Munich, Germany
1993 Aerostar XL Ext. 3.0L
Tom Ucen
Munich, Germany
1993 Aerostar XL Ext. 3.0L
Posting Guru
Joined: Sep 1999
Posts: 2,297
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From: Indiana
Tire Size & Speedo Error
My Aerostar also came with the 215x70x14's which is what the door jam decal calls for. I have seen that it appears the 215x75x14's are on the long wheelbase vans. Is this right? All the short ones I've owned came with the 215x70x14's. My speedo is off also. I have done as the others and checked it against the mile markers on the highway. It registers about 2 mph faster than what it is actually going.
Superdave
94 Ford Aerostar XL 3.0L
82 Ford F250 4x4 XLT,400 CID,C-6 A/T,8700lb GVWR. Black & Silver
Superdave
94 Ford Aerostar XL 3.0L
82 Ford F250 4x4 XLT,400 CID,C-6 A/T,8700lb GVWR. Black & Silver
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