In selecting replacement tires Web tire calculators get you in the =
ballpark. However for the best match you need to user the tire =
manufacturers stated "revolutions per mile"(rpm).
I have found that the same advertised size tire revolutions per mile can =
vary over ten percent depending on the manufacturer and tire design. =
On the Dunlop Web site
<http://www.dunloptire.com/>
various Dunlop Light Truck tires ratings follow:
215 75R15 list 774, 786, and 806 rpm's. (4%)
235 75R15 list 718, 741. 745, 753, 756, 773, and 804 rpm's. (11.9%)
This varies significantly from the data calculated at
<http://pw1.netcom.com/~sgalaba/tiresize.htm#ustires>
215 75R15 =3D 728 rpm's.
235 75R15 =3D 698 rpm's.
I am assuming that the calculator is using an "ideal" tire or uses a solid =
model that does not take into account the flexing of the tire contact =
patch.
I guess it boils down to doing your homework...
Craig Baltzer wrote:
>Sorry Mike, forgot to mention its a '97, 5.2l, 3.55, 5sp.
>
>There was some discussion before on this, but no one seemed to know if
>the DRB would acutely allow variable recalibration, or could just
>compensate for the 2 tire sizes available from the factory and the 3
>different rear-ends. Maybe its time to wander into the dealer and find
>their DRB expert...
>
>Craig
>
>-----Original Message-----
>From: Mike Crumbly [malt:mcrumley@airmail.net]
>Sent: August 31, 1998 1:10 PM
>To: dakota-truck@buffet.net
>Subject: Re: DML: Speedo recalibration
>
>
>At 12:54 AM 8/31/98 , you wrote:
>
>>I'm about to switch over to some different wheels and tires on my Dak
>>which will throw off the speedo (going from the "stock" tires which
>have
>>an outer diam of 31.5 to a new set which are going to be about 30). Any
>>suggestions on the best approach to get the speedo recalibrated to read
>>accurately after the change? From my rough calcs it will be reading
>>about 5-6mph fast after the changeover...
>
>Might wanna check the archives to be sure (this has been discussed
>before)
>but if I remember correctly, it's a computer reprogram that has to be
>done.
>BTW, might help to know what year Dak you have.
>
>
>--
>Mike Crumley mcrumley@airmail.net
>97 RC 3.9L V6 3.55 Auto Rhino Liner
>Bug Shield Mud Flaps DDBC
>
I hope this helps.
Mark Bate
KD6RMI@K6.net
+1.510.429-9100
Think different... Beware of geeks bearing gifts.
W 116.33 Euro/M 117.??
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