If your going to upsize the tires get the 4.30:1.

the stock tires are 34".


I wonder how much it will effect it on 35's. My diesel couldn't tell at all

With the 7.3 gas & F250 your ratio options are 3:55 or 4:30 - with a F350 ratio options change to 3:73 or 4:30.

---> 2020 Ford
If you go to the build your own part of Ford's site, you'll see the various ratios being limited/removed depending.

I'm also interested in the 7.3.

I'd have no hesitation replacing my 6.2 / 4:30 with another just like it, really have no need for more, tow / haul with mine frequently.

I'd go with the 4.30s. In fact, I passed on a used truck that was everything I was looking for except it had the 3.55s. If you have an opportunity, drive them both so you can really see the difference. Mileage wise, you're really not missing out by going with a little taller gear. Drive wise, it's night and day.

A tad off topic but here is an interesting perspective on a guy welding pipe out of a gasser rig. You have to get about seven minutes in before he gets around to saying why he's actually back to the gas truck. One of my clients for a couple of years was a popular preowned 4x4 diesel truck dealership that will remain unnamed. I did all of the analytics and digital marketing so I have unique insight on what was actually selling. While I won't get into specifics I can say that while the gasser rigs were rare, they sold in a fraction of the time as the diesels.

This is somewhat like the Tesla chainsaw thread, if you need a diesel get one. If you don't, it's OK to consider a gasser.

Blue Moon

The 7.3 will come with either 3.55 or 4.30. I have the stock 18s on my 4.30 geared truck (crewcab/longbed) and get about 13 hwy/10 city. But I'm done worrying about mileage. Life is simply too short and an extra couple hundred bucks per year isn't worth worrying about. It's an 8,000 lb heavy duty pickup and it will get heavy duty mileage.

In a gas powered HD pickup that is used for towing, hauling, or wears larger tires, you should get the lowest gears offered. I'm sold on the 4.30 gears and wouldn't trade this truck for the Cummins it replaced.