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View Full Version : RPMs 65, 70, 75 with larger tires


RLS
01-11-2003, 09:02 PM
I know that several of you have put larger tires on. I would like to do that but don't want to lower RPMs too much.<br><br>If you have larger tires and the 6 speed please tell me what RPMs you are running at;<br><br>75, 70, 65. I ordered 3.73 rear end.<br><br>Please included tire size.<br><br>I guess I need a base line so if someone with stock tires would also please give their input that would be great.

UTAH
01-12-2003, 02:03 PM
I have not checked out all the speeds you listed, but I know I run 1900 RPMs at 70 MPH with 315/70/17 tires, 6 speed, and the 3.73 rearend (speed is corrected to account for new tire size).<br><br>Just a thought - the actual sizes of tires on big tires often differs from 1&quot; to 2&quot; by the size listed by the mfr. The major tire companies list the actual sizes of their tires either on the web or at the dealer. My tires are closer to a 34&quot; rather than a 35.&quot;<br><br>Best to y'all<br>Bill :)

RLS
01-12-2003, 09:23 PM
Utah,<br><br>Thanks, I pull my boat between 65-70 and don't want to shift down for small hills. I've read where 1700 rpms is the start of the sweet spot but I don't know. <br><br>At what rpm do you feel like you need to shift down? <br><br>

UTAH
01-13-2003, 05:08 AM
RLS - Shift down? Hmmmm.... don't do that much with the new truck. ;D But, if loaded and hitting a good incline, I'll go from 6th to 5th at about 1500-1600 RPMs. That puts me right back in the sweet spot.<br><br>Best to y'all<br>Bill :)

RLS
01-13-2003, 09:35 AM
That what I needed to know. Unloaded I'm not sure downshifting would be an issue but loaded I am not sure.<br><br>If you are at 1900 rpm at 70 mph and you may be at 1750-1800 at 65 how much hill will be needed for a down shift? <br><br>With stock tires I think I read 2000 rpms equal 68 mph. That would make towing about perfect but when I crusie unloaded at 75 the rpms will be 2100-2200 and may hurt fuel milage. <br><br>Thanks for your input .

BADBOWTIE
01-25-2003, 09:29 PM
:) Newbie here, how are you guys correcting your speedo for the larger tires you are putting on? I would love to put on bigger tires but an unacurate speedo is the hold back. Thanks.<br> Jason

Commatoze
01-25-2003, 09:48 PM
<br> :) Newbie here, how are you guys correcting your speedo for the larger tires you are putting on? I would love to put on bigger tires but an unacurate speedo is the hold back. Thanks.<br> Jason<br><br><br>Hold back no longer:<br>http://www.autotransinc.com/Recal.htm<br>http://www.abbott-tach.com/era.htm<br><br>Another alternative is to use a GPS unit, and use the speed readout on it. Mine GPS V is very accurate.<br><br>Tom Hybiske<br>

davec
01-28-2003, 10:56 AM
Going from the 265 to the 315 was an 8.02% speedo/odo error reading...<br><br>At 65 on the speedo, I'm doing 59ish