Yet another Tire/Wheel/Lift question!

[DuvallDawg]

I have a 77', cut, going to a 3.5 in suspension lift. Question I have is, I have a line on a set of 15x10 wheels with 35x12.5/15 tires. Will the 3.5" be enough or will I need to add a BL as well? No overly serious rock crawling happening any time soon. More of an occasional fire trail, light off road use...

Thanks for the help as always!

 

[stock1970]

you will be fine.

 

[Apogee]

It depends on how "cut" you are and how hard you flex it. If you don't mind trimming to fit, you shouldn't have many issues. Most would add a 1" to 2" body lift to comfortably clear 35's.

 

[DirtDonk]

Better make sure of the backspacing on those wheels too, before you fork over money. Or else be ready to spend a little more on wheel spacers just in case.
Not really a huge issue, but if you're on a budget and don't want to spend for a nice set of billet spacers, make sure the wheels have less than 3 5/8" backspacing (I think that's the limit?) or the rim edges may very well hit the steering arms and tie-rod ends on your '77.

A 3.5" bs rating is usually best I think. Others will remember the exact spec, so wait for confirmation. But check with the owner anyway, to see if they know what the spec is on those wheels.
Unfortunately, that little backspacing on 10" wide wheels and 35" tires also puts some serious "english" (leverage) into the steering linkage. Are you changing our your stock Inverted-Y steering setup for the less flexy Inverted-T of the earlier EB's.

The "Y" linkage was great, but add a lift and bigger tires on wide wheels and it's usually not a happy driver after that.

Paul

 

[DirtDonk]

Oh, and while they might fit under normal circumstances, like the others said, when you add the wide wheels sticking out quite a bit, the front tires travel in a pretty big arc when steering. Making clearance in the front a very scarce commodity.
I think that might be what Apogee was referring to with the trimming comment.

A lot is going to depend on the offset/backspacing of the wheels.

Paul

 

[DuvallDawg]

Thanks for the info guys, learning lots on my first build through here!
The offset/BS on these wheels are -48/3.61. I would like to hear or read up more on any potential steering issues. Getting a pretty good deal on these but I don't want to start up a whole new set of problems by putting these on? Also, is this going to mess up my gearing assuming that I have the 4.11?

 

[bronconut73]

Thanks for the info guys, learning lots on my first build through here!
The offset/BS on these wheels are -48/3.61. I would like to hear or read up more on any potential steering issues. Getting a pretty good deal on these but I don't want to start up a whole new set of problems by putting these on? Also, is this going to mess up my gearing assuming that I have the 4.11?

With a strong engine 4.11 gears with 35's would be "ok".
Some would say 4.56's would be better.
Stock 4.11 and 4.56 gearing was usually only available with the 6 banger.
The V8's more commonly have 3.50 gearing.
Are 3.50 gears good with 35's?......Well I guess.....but maybe good isn't the best way to describe it. 3.50 gears "will" work but it will be hard on an auto tranny or clutch and proper gearing really makes a big difference in mileage and especially performance.

 

[DuvallDawg]

Ok,went back to my spec sheet and verified some stuff.

77' with 351W NP 205 and 435

front differential - stock 77 bronco Dana 44 3.54 ratio

Rearend - ford tapered housing 9” stock 77 bronco 3.50 ratio limited slip.

Guess I am still concerned about steering issues. If I am having to swap out the Inverted-Y for T, then all of the sudden my "deal" on the wheels and tires isnt much of a deal anymore.

 

[DirtDonk]

Well, I wouldn't necessarily lose out on a great wheel & tire deal just for the steering at this point. But I'd sure look at the deal more closely than normal just to make sure that it all is going near enough to be what you want.
Sounds like you're already committed to a lift and larger tires & wheels no matter what, so you're very likely going to have to address the steering eventually anyway.
One way or another.

I'd say that many, if not most owners of '76/'77's try to make the Y setup work for them at first. But eventually most end up changing out to a T after all. Even those that aren't running 35's on 10's. It's just too flexy-flier feeling and prone to more severe changes in toe-in as the suspension is cycled.
Not only that, but if you intend to wheel it at all on anything resembling a tough trail, the long-side rod is super prone to going all taco on you. At the worst possible moment of course.

My personal preference runs to the 35's with 8" wheels with 3.625" to 4" backspacing, but lots of Bronco owners swear by their 10's. The 8's don't stick out as far, are easier on the steering, protect the rim edge better and, to my eye at least, just look better.
Yes, you lose the deeper dish look of the wider wheels, but to me that only looks good on the right vehicle. And EB's were rarely that right vehicle for that look to me.

That said, you can make just about anything work. But once you've lifted, you're likely going to end up wanting one of the updated steering linkage setups.
Bottom line, if the deal is too good to pass up, don't. But if the tires are used or in unknown condition, pass on it because you can always find a wheel tire combo you like better. Sometimes a good deal isn't, when the tires aren't so great.

Paul

 

[DirtDonk]

Oh, and regarding what you and bronconut were just discussing, he's right no the money with the gear-vs-tire size thing.

Your 3.50's will work, but you won't be happy very long with 35's. Even 33's are pushing the limits of sanity if you want to play. Sure, it'll ride along fine, but you'll definitely notice a loss of power compared to smaller tires.
For 35's, I'd agree that 4.11's are just the minimum. But will also work very well depending on the engine and transmission and tire size.
Oh boy. Here we go again with all that "it's a system" kind of stuff! %)

Paul

 

[DuvallDawg]

So what is an optimal Gearing ratio for larger wheels and tires just out of curiousity?

 

[DirtDonk]

Hate to put it this way, but for the sake of discussion... The word "optimal" doesn't exist here. ;D

More like an optimal range if anything. All depends on what the individual likes/wants, with how the engine is tuned (where the power comes in and goes away), the type of transmission, and the EXACT tire size. I emphasize the word "exact" because even one size difference can make a very noticeable difference in some vehicles. While the jump from 32 to 33 inch, or from 33 to 35 inch tires might not make much difference to some, for others it makes a huge difference in feel and performance.
So just like a lot of things with Broncos, "it depends" on many things.

But to narrow it down, for our purposes of general Bronco use, most people like the 4.11 to 4.88 range. With 4.11 being biased to street use with a good torquey engine, 4.56 being good for a large group that likes to do it all, but spends more time on the road than on the trail, and 4.88's for those that prefer to bias their performance to off-road and/or have an overdrive transmission they can use on the highway.
With an overdrive, either auto or manual, 3.50 gears would make overdrive pretty much useless (even going down hill sometimes!) and even 4.11's would be borderline with 35's. Better with 33's.
So with 35's and an overdrive, 4.88's might give you the best of all worlds, with 4.56 leaning more towards the street and a torquey motor.

Then again, you have to factor in the front axle, which, unlike the rear Ford 9", gets weaker as you go down in ratios (higher numerically). Which means that if you're a hard charging off-road foot-stomping fun-loving driver, your front 4.88 might snap it's pinion the first time out.
But that's another subject...

Paul