ring gear vs. tire size
#1
ring gear vs. tire size
I have a 2001 F-150 2wd with a Fabtech 7.5" lift kit and 2" lift hangers. I am currently running 20's with about a 31" tire. The truck kicks in and out of o/d as or is. I am installing a set of black 26" wheels and plan to change my ring an pinion. I think I have a 3.55 and was wondering if a 3.73 would be enough to offset the lift and wheels or should I go with a 3.90?
#3
Its a 35" tire. The has made a big difference because of the wind drag. I want to install a gear where the truck isn't struggling to keep up. But I figured because wheel weight will be heavier than tire weight I would to compensate for like 38's. BTW I had 38's for a while and I couldn't drive with the o/d on.
#5
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#7
Its a 35" tire. The has made a big difference because of the wind drag. I want to install a gear where the truck isn't struggling to keep up. But I figured because wheel weight will be heavier than tire weight I would to compensate for like 38's. BTW I had 38's for a while and I couldn't drive with the o/d on.
There is much more in play than just static wheel and tire weights.
There is also rotational inertia ( mass being concentrated farther from the wheel center ), and increased rolling resistance - which includes factors such as: tire tread design, inflation pressures, rubber compound and tread width.
Spring rates will be off, as will shock damping calibrations.
Lastly - there is the increase in leverage due to the larger radius of the wheel/tire assembly - which will drastically reduce your braking effectiveness, hence increase stopping distances. Most folks do not factor in a brake upgrade when going larger - but they should.
BTW - I agree that yer already-poor aeros (it's a truck) get even worse with a lift at speed.
You are a candidate for 4.56's, at least. Perhaps even 4.88's +.
A custom-tuned programmer would beneficial to recoup some torque and correct for tire size and gear ratio so your speed is accurate and your shift points are correct.
Last edited by MGDfan; 11-13-2013 at 07:40 PM. Reason: can't spell braking, lol. Nor wheel - lmao
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#9
That's why I came to ya'll. I knew you guys would be the ones to ask. I don't plan on setting any land speed records. I just want to be able to set cruise at 70 or 75 and not feel like I'm killing the truck. Oh btw my truck has the 5.4. If you click on my name you can see the way the truck looks now. I hope to start prepping for paint soon. Also, I do plan on installing a big brake kit from SSB.
#11