Greg she looks awesome man

 

Ok a few more newbie questions...
I've seen a little info on swapping gears when increasing tire size. I definitely see the point when towing significant weight. What size tire makes this necessary if at all and is it if I'm not towing anything substantial? How does tuning the v-10 with an SCT factor in this scenario since the speedo correction can be made through that?
Also wonder if anyone has any experience with Cooper SST Pro on their Ex?

Sorry I'm dumping a lot of stuff that doesn't apply in this thread but I've read the whole thing and there's a bunch of experienced guys in this one

 

Taller tires will lower the effective gear ratio, a (numerically) lower gear ratio will be less efficient at transferring the available power to the ground. Yes this will be more noticeable if towing, especially towing heavy but it will also rob you of everyday driving performance with slower acceleration and increased stress on the transmission. So while those new big tires may make the rig look cooler/tougher/meaner/faster without a gear change they are actually making the rig slower/less responsive/weaker.
The V-10 makes it's most usable power above 2k RPMs, the more common 3.73 gears run just below that range at highway speeds, so any increase in tire height will move you farther away from that power. The factory optional 4.30 gears run just over 2k RPMs at highway speed and as a result deliver better acceleration, easier towing and hill climbing and improved all round performance. To make a comparison, 4.30 gears with the stock 31.5" tires provide "good" performance, 3.73 gears with the 31.5"s are a "adequate" but less than impressive. Now if you swap on a set of 35" tires with those 4.30s the effective ratio drops to 3.87, or just about the same "adequate" level of performance as the 3.73 truck. If you have the more common 3.73 gears and mount up those same 35"s the effective ratio drops to 3.36 which would result in "poor" performance. And a set of big old 37"s being spun by those 3.73 would have an effective ratio of 3.18 which would feel like "Yugo" performance (or lack there of...)
Depending on what gear ratio you are starting with, the size tire you want to run and the level of performance you want all need to be mashed together to decide if you need a gear change and if so, how much of one. It's a personal choice, there is no hard and fast rule that says this tire size has to have this gear ratio. we have had guys with stock tires change to deeper gears and guys with 3.73s running big tires. I like to use this easy online tire size gear ratio calculator to figure it all out. 4Lo.com :: Tire Size Change, New Gear Ratio Calculator
I have run and towed heavy with the following gear/tire combos: 3.73/31.5" (effective 3.73), 4.88/32" (effective 4.80) and 4.88/35.28" (effective 4.39). They all had very different performance characteristics.
The SCT handheld tuners can not change a V-10 rig's speedo based on different tire sizes. Read this current thread about this. https://www.ford-trucks.com/forums/1...orrection.html Most of the diesel rigs can make the change with the tuner but for whatever reason the V-10s seem to need a deeper reaching tool to make that change, like the Auto Enginuity or the Ford dealer can change the revs per mile for bigger tires.
Otherwise the SCT is a great tool when paired up with some custom tunes from a shop like 5Star Tuning, a site sponsor.

 

Thank you Tom, that's exactly what I was looking for

 

 

looks great big T, what on the windshield

 

I think that's just the flood light on my house behind it maybe?

 

Looks like frost to me

 

Ahh, no that's dew!
South Louisiana!
I took that pic the other morning and if your car isn't under a carport or in a garage it gets wet over night down here. Gotta love that humidity

 

Gotcha. We're already getting frost here and some snow.

 

cant say I'm jealous of that

 

Big T,

Love those wheels and tires! What size combo do you have there?

 

I went from 3.55 to 4.56 on my Explorer. I have 33" tires (stock was 29). The effective gear ratio is now about 4.10 (which was an optional ratio from the factory). It makes it so much more fun to drive on the street. And of course off road (it's primary purpose) it is phenomenal.

Don't fear the gear!

I'm thinking of regearing my Expedition. Stock tires are between 30-31 and I'd like to go to 33s. Has 3.55 on it now. I'd probably go with 4.10s to not overdo it- this one does spend a bit of time on the highway/interstate.

 

 

Give us some info on your X. Great looking rig.