EB towing with 33's or 35's?
10-26-2011, 01:53 PM
#1
Sand Addict
Thread Starter
EB towing with 33's or 35's?
Anyone towing heavier (6500-9000lbs) with their EB with 33-35's on it? Any regrets? I ordered an fx4 with 3.73s and am already itching to level it (and im still about 6 weeks out on delivery 
). Wondering everyones opinions power and mileage wise compared to stock.
). Wondering everyones opinions power and mileage wise compared to stock.
10-26-2011, 01:55 PM
#2
Senior Member
i'm towing with 285/55R20's, that's a 32.4'' tall tire. I've be willing to say a 33" won't make much of a noticeable difference, the 35" will for sure - Get the 4:10 gears if that's your plan.
10-26-2011, 04:20 PM
#3
Calculate the %'s for each tire and rear end ratio.
For example: If you start with a 3.15 rear and put 35's that will end horribly, and soon as you will end up with an effective rear end ratio of ~2.5ish. Starting with a 3.73 and putting 35's should still keep your ratios in a safe zone.
A stock tire is 30" so going to 33" is 1.10% which should effectively reduce your 3.73 by ~90% = 3.5ish... do the same for 35's and you ill probably be down to 3.2ish (I'm guessing). From there you can use the factory towing specs for the rear end range you will be experiencing.
Good luck.
For example: If you start with a 3.15 rear and put 35's that will end horribly, and soon as you will end up with an effective rear end ratio of ~2.5ish. Starting with a 3.73 and putting 35's should still keep your ratios in a safe zone.
A stock tire is 30" so going to 33" is 1.10% which should effectively reduce your 3.73 by ~90% = 3.5ish... do the same for 35's and you ill probably be down to 3.2ish (I'm guessing). From there you can use the factory towing specs for the rear end range you will be experiencing.
Good luck.
10-26-2011, 07:35 PM
#4
Senior Member
Originally Posted by superccs
Calculate the %'s for each tire and rear end ratio.
A stock tire is 30" so going to 33" is 1.10% which should effectively reduce your 3.73 by ~90% = 3.5ish... do the same for 35's and you ill probably be down to 3.2ish (I'm guessing). From there you can use the factory towing specs for the rear end range you will be experiencing.
Good luck.
A stock tire is 30" so going to 33" is 1.10% which should effectively reduce your 3.73 by ~90% = 3.5ish... do the same for 35's and you ill probably be down to 3.2ish (I'm guessing). From there you can use the factory towing specs for the rear end range you will be experiencing.
Good luck.
10-26-2011, 08:01 PM
#5
Senior Member
Yes 32.1" I went up to a 33.1 DuraTrac have a 2" level with the 3:73 ELD get 9-10MPG pulling 6k.
FYI the Duratracs will effect your milage pretty significantly. At least that is my situation. They look bad***** though.
Pic for perspective
FYI the Duratracs will effect your milage pretty significantly. At least that is my situation. They look bad***** though.
Pic for perspective
10-27-2011, 12:20 AM
#6
I'm towing a 24' (26'+ with swim platform & about 30' with the trailer) Regal Cuddy with my FX4 Eco SCrew that has 35s with 4:10 gears (the 4:10's come out to be 3.7's with the 35's if you do the math) and a Rancho 4" lift. The boat loaded with fuel and the trailer comes in at just over 7000lbs.
The truck you see in the pic (1997 F250LD - like and F150) with the boat also had 35s with a 6" lift (my old Ford) and it sat about 2" taller than my new FX4 which is just under 7' tall. Anyway, my old Ford with the 5.4 and 3.73 gears could hardly pull the boat up hills and last summer I smoked my trans (complete slipping) coming up the hill in my neighborhood (7-8% grade for about 150yards) which cost me $3K for a full trans rebuild last year. Early this summer, the old truck started to shudder again pulling my boat up our neighborhood hill (even in 4wheel-low) so I sold it before the trans totally went out again and bought the FX4 Eco Screw you see in the other pic. Wowwww, there is absolutely no comparison in pulling my boat with my old F250LD versus the Eco Screw. In fact, most of times I pulled the boat this summer I almost forgot I had it behind the truck at times. And as for my neighborhood hill the FX4 Eco could probably hit 60 (haha), if i didn't take my foot off the gas (but I've followed the speed limit with lots of power in reserve and the truck upshifting), where my old truck would crawl from the corner at 20mph down to about 5mph all the way down to 1st gear - gutless........But the Ecoboost, I've always had power to spare. What's funny is that the Ecoboost is a 3.5L, where my boat has an 8.1L engine. So, for all those that have complained about the Ecoboost mileage while towing.....well the Eco it fantastic for gas mileage versus what my boat burns at WOT at 60+mph (yep - 15+ gallons per hour).
To give a better idea of how big the boat is, if you look at the license plate on the left side of the boat trailer it's a mini plate (what you'd put on a motor cycle, not your full size license plate that's on a truck/car).
Hope this helps and I would not hesitate to pull an extra few thousand pounds based on how the truck is set up right now. It also goes up/down the local Northwest Freeways at 70mph never slowing down from any of the grades.
The truck you see in the pic (1997 F250LD - like and F150) with the boat also had 35s with a 6" lift (my old Ford) and it sat about 2" taller than my new FX4 which is just under 7' tall. Anyway, my old Ford with the 5.4 and 3.73 gears could hardly pull the boat up hills and last summer I smoked my trans (complete slipping) coming up the hill in my neighborhood (7-8% grade for about 150yards) which cost me $3K for a full trans rebuild last year. Early this summer, the old truck started to shudder again pulling my boat up our neighborhood hill (even in 4wheel-low) so I sold it before the trans totally went out again and bought the FX4 Eco Screw you see in the other pic. Wowwww, there is absolutely no comparison in pulling my boat with my old F250LD versus the Eco Screw. In fact, most of times I pulled the boat this summer I almost forgot I had it behind the truck at times. And as for my neighborhood hill the FX4 Eco could probably hit 60 (haha), if i didn't take my foot off the gas (but I've followed the speed limit with lots of power in reserve and the truck upshifting), where my old truck would crawl from the corner at 20mph down to about 5mph all the way down to 1st gear - gutless........But the Ecoboost, I've always had power to spare. What's funny is that the Ecoboost is a 3.5L, where my boat has an 8.1L engine. So, for all those that have complained about the Ecoboost mileage while towing.....well the Eco it fantastic for gas mileage versus what my boat burns at WOT at 60+mph (yep - 15+ gallons per hour).
To give a better idea of how big the boat is, if you look at the license plate on the left side of the boat trailer it's a mini plate (what you'd put on a motor cycle, not your full size license plate that's on a truck/car).
Hope this helps and I would not hesitate to pull an extra few thousand pounds based on how the truck is set up right now. It also goes up/down the local Northwest Freeways at 70mph never slowing down from any of the grades.
Last edited by Hofmanns4rj; 10-27-2011 at 12:28 AM.
10-27-2011, 11:21 AM
#7
Senior Member
@ 15gph!I'm in the process of repowering my boat w/ a pair of Yamaha 300hp V6 outboards. I'm hoping to get a little better economy than I did with the old motors. If I get 2mpg and burn less than 20gph @ cruise (probably 40-45gph WOT), I'll be ecstatic!
Thanks for the tow report, though. I'm hoping to move into an EcoBoost in the spring, which I may use to occasionally tow my boat, which will be close to 11k lbs. if all the tanks are full.
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10-27-2011, 12:34 PM
#8
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Thank you for the post Hofmanns4rj. I too have a "smaller boat" 
. An 05' Sea Ray 215 Weekender. 22' Deep V Cuddy with a 5.0 and Bravo 3. It's about 5K dry, then add the tandem trailer.....
Anyway, the boat was the main reason I purchased the ECO. I haven't towed it yet (winters on the way), but I feel very confident that I shouldn't have any issues. I too have 3.73 rear with 20" stock rims.
. An 05' Sea Ray 215 Weekender. 22' Deep V Cuddy with a 5.0 and Bravo 3. It's about 5K dry, then add the tandem trailer..... Anyway, the boat was the main reason I purchased the ECO. I haven't towed it yet (winters on the way), but I feel very confident that I shouldn't have any issues. I too have 3.73 rear with 20" stock rims.
10-28-2011, 12:12 AM
#9
LMychajluk - if your really thinking about pulling 11K with you Eco, please read all the post on the topic within the forum and really consider what you are going to get for gearing. As noted, I have 4:10s (3.7x's with the 35's) and I'm glad the gears are not any higher. Looks like there are also a number of members that went below 3.73s and while noted OK at 3.73's it seems like a few others wished they had gotten lower gearing. So, do your homework if you plan to pull that much especially if you live in an area with lots of hill like I do in the Seattle Wa area....
10-28-2011, 10:35 AM
#10
Senior Member
Yep, but thanks for the tip, Hof. I'd be looking at an FX4, so I'd get the 3.73's at a minimum, and may still opt for the 4.10s. The 11k lbs would be a worse-case scenario (more like 9k-9500 with the tanks close to empty), and towing would be infrequent (2-4 times year, max) and relatively short range (~100 miles).
From what I've been reading, the 4.10s shouldn't make that much of a difference anyway, MPG-wise during everyday driving. And 4.10s w/ 35" tires is almost identical gearing-wise to 3.73s and 31.5" tires. I just moved up to a (almost) a 33" tire on my current truck w/ 4.10s (Chevy w/ the 5.3L and 4-spd tranny). It's only been a week, and I still need to re-calibrate the speedo, but I think I may actually be getting a little better MGPs, just because my RPMs are a bit lower at cruising speeds.
From what I've been reading, the 4.10s shouldn't make that much of a difference anyway, MPG-wise during everyday driving. And 4.10s w/ 35" tires is almost identical gearing-wise to 3.73s and 31.5" tires. I just moved up to a (almost) a 33" tire on my current truck w/ 4.10s (Chevy w/ the 5.3L and 4-spd tranny). It's only been a week, and I still need to re-calibrate the speedo, but I think I may actually be getting a little better MGPs, just because my RPMs are a bit lower at cruising speeds.