265s on '99

[Big A]

Fellas,
I have a '99 auto that came with 245 tires. I would like to change to 265s,but I'm afraid it will lower my ratio too much. I have the 3:54s. Has anyone done this swap? What rpms will the truck run at 65, with the OD off.
Thanx
Big A

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'99 3/4 24 valver Quad,auto,KN stock, westin powder black pushbar.

 

[HEMI®Dart]

Big A,

I doubt you would even notice a difference. You are not going much taller.

My buddy had the stock 245's on his 99 auto and we switched my 36" tall tires on his for a test. He felt there was no loss in low end power. He said the transmission seems like it shifted cleaner.

You won't even notice a difference from 245's to 265's.


More Info here: https://www.turbodieselregister.com/ubb//Forum3/HTML/002421.html

 

[JKloppe]

I have added 265's snd there is no difference at all. They look better though. I got them at a great price (free), after these are dead i will put 315's on, with levaling springs. With that big of difference I bet I will notice the gear ratio change then

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99 2500 4x4 QC, auto
cowl hood,strait pipe,Armorthane bedliner, ultalight gauges/ A-pillar

 

[BLACKRAM]

I would have the 285's and love them. That is about the largest tire that will fit properly on a stock rim and still go through a car wash. As for effective gearing a change from 245 to 285 on a 3. 54 rear is the same as 3. 21 rear. At 70 mph my speedo reads 63 mph. Check the number of tire revolutions per mile for the 245 and your tire of choice. You can get the info from the tire dealer. Divide the difference. The answer will be the percentage your speedo will be off. Going from the 245 to 285 is roughly 10%. Divide 3. 54 by 110% (to automatically subtract 10%)and you get 3. 21. The side benefit is your odometer will show the same 10% decrease in actual miles driven. If you put 285's on day one of ownership, you get to travel 39,600 actual miles before your warranty expires. #ad


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1999 2500 4x4, auto, 3. 54, HD241, Quad cab SLT, Blk Sport Pkg, 285 Bridgestone AT, Amsoil.
1992 SC400
1978 Mooney 201 IFR

 

[csutton7]

I'll second that-----chris--but I do like my new 4:10 gears better w/ 35" tires

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chris sutton
1999 2500 qcab longbed 4x4 red sport w/ all the options 'cept plow pkg, 4:10 detroit locker in rear & front ARB,
5" skyjacker lift w/ 35" BFG mud terrains on 16. 5x9. 75 Weld rims, black nerf bars, black bug persuader, black lumber rack,
camel leather int. w/ mb quartz spkrs and 8" sub, power edge EZ, DTT vb & tc, mag hy-tec transmission pan, red magview diff covers &
coming soon: 275 injectors, L&L ladder bars, tubo temp monitor & guages on "A" pillar

 

[CJ]

I have 245's and 4:10 gears. I borrowed some 285's to see if I could still fit in the garage and to see if I noticed a difference when driving, I did not.

Here are some links to a gear ratio calculator.
http://www.corral.net/tech/gearcalc.html
http://www.rbelectronics.com/cherokee/gears_calc.htm

 

[RKohn]

265's were stock on mine and I want to go taller to get the rpm's down. Like the look of the 305-70's, but know 255-85's will cut the snow better. another dang decision. There is no doubt that the Cummins will turn'em.

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Y2K Red Stealth Sport 2500 4X4 QC SLT+, 5-spd, 3. 54 anti-spin, 265-75-16 LTX’s (There ain’t no such thing as options, cause ya gotta have it all, including: DC’s dead cow/vinyl interior and don’t stop anti-lock brakes. ) Stock, but not for long. Oops, too late. What silencer ring? (More fun than my 98 SST)

 

[Big A]

Thanx for the help guys. I'm going to tow a much heavier trailer,so I'll most likely tow with the OD off. Thats why I was curious about the RPMs at 65 with the OD off.
Thanks again
Big A

 

[SOLER]

My Y2K and my '01 both came w/ 265s and 3. 54s.

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Shane Oler
'01 2500 4X4, ETH/6 speed, Pyro (pre-turbo)and Boost Pillar mount, Dark Garnet/Camel, 20K Reese 5er hitch

Other: '70 Olds Vista Cruiser 455 (future resto project)
30' Sandpiper 5er Super Slide bunkhouse(about 10k lbs. )

 

[Cooker]

I just get in here and agree with everyone else, you won't know a difference other than the speedo being a bit off.