Differentials and axles differences strengths

[Alanp970]

It does represent the ring gear in millimeters and to map it backwards:

M190 = Dana 35 (while it could be semantics, the D35 is typically a M186)
M220 = Dana 44
M235 = Dana 50 (this seems to be a new offering specifically for the Raptor as the axle that is above a D44 would be a D60).

Dana Advantek ring and pinion gears are the same strength no matter what gear ratio they represent--in the same axle size. Historically, you will hear people say that lower the gear ratios (higher numerically) that the R&P is weaker versus a higher gear ratio. Dana does not specify a different torque rating per ratio, so they are all the same strength and Dana explains it here.

Where the "weakness" comes into play is case/axle deflection whereas installing larger tires provides additional traction which is then transferred to the axle housing. This in turn can case the pinion gear to move away from the ring gear limiting tooth engagement and thereby breaking the teeth.

In addition, the extra torque that is applied can either cause the front axle CVs fail or the front or rear axle shaft twists permanently. We saw the housing deflection or axle twists happen in the Wrangler which has the same axles (though a solid axle in the front), but an engine with far less HP/TQ than the 2.7L in the Bronco, ergo it is more likely to happen in the Bronco when larger tires are installed.

The Dana 50 has been around a long time….at least as a front diff. If I remember correctly the Twin Traction Beam F250’s in the 90’s (and possibly 80’s) were a Dana 50. I don’t recall a Dana 50 rear but it wouldn’t totally surprise me if there was a light duty 3/4 ton rear like that. And by the way I completely agree with your assessment of a 37 vs smaller tire breaking things.

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[Fordified1]

I do believe that weight of the tire also matters. But the difference in weight probably doesn’t matter as much as the diameter due to the leverage.

Now fill those tires with concrete and yea you’re gonna break stuff trying to accelerate all that weight and stop it.

 

[CarbonSteel]

The Dana 50 has been around a long time….at least as a front diff. If I remember correctly the Twin Traction Beam F250’s in the 90’s (and possibly 80’s) were a Dana 50. I don’t recall a Dana 50 rear but it wouldn’t totally surprise me if there was a light duty 3/4 ton rear like that. And by the way I completely agree with your assessment of a 37 vs smaller tire breaking things.

Pretty sure the Dana 50 that is in the Braptor is an Advantek and is a new design.

 

[Alanp970]

Pretty sure the Dana 50 that is in the Braptor is an Advantek and is a new design.

I’m sure it is. I just thought you meant Dana always went D44 right to D60. We all just wanna argue with you tonight

 

[CarbonSteel]

Hmmm, yup, you guys are both right, I got that point backwards. I owe @CarbonSteel a steak dinner...

However I'm not sure how we arrived at this point. Where we started was with @CarbonSteel saying the OD was the only factor that matters, and me saying, no, other things matter as much or more, and I still stand by that.

The OD is not the only factor that matters with regards to breaking axle shafts and ring and pinion gears, but it has more impact than the weight of the tire due to the mechanical leverage (disadvantage).

Weight comes into play for wear on ball joints, shocks and other suspension components due to the fact that you are increasing the unsprung weight over (potentially) the design limits.

In any event, none of the non-Raptor Broncos were designed for 37" tires due to D44 or smaller axles. In addition, one would be wise to watch the weight of 35's given they come from the factory with Load Range C tires which could make one question the design limits IF the weight was factored into wear versus simply MPG and CAFE credits.

 

[zuke]

The OD is not the only factor that matters with regards to breaking axle shafts and ring and pinion gears, but it has more impact than the weight of the tire due to the mechanical leverage (disadvantage).

Weight comes into play for wear on ball joints, shocks and other suspension components due to the fact that you are increasing the unsprung weight over (potentially) the design limits.

In any event, none of the non-Raptor Broncos were designed for 37" tires due to D44 or smaller axles. In addition, one would be wise to watch the weight of 35's given they come from the factory with Load Range C tires which could make one question the design limits IF the weight was factored into wear versus simply MPG and CAFE credits.

OK, sounds like we are now as close to agreement as we are gonna get, I agree with what you are saying above, the mechanical advantage of the OD in a bind situation is the biggest factor in breaking an axle. I still think the weight is the biggest factor in shock loads like impacts (Bumping) and bouncing situations, although the mechanical advantage of the OD definitely plays a part in that as well (when the tire comes down from the bounce and suddenly has traction)

And I definitely agree that the weight is the bigger factor in wear over time.

Oh, and yes, only the Braptor was designed with 37"s in mind, but any one who modifies at all is going beyond the original design, and careful consideration should be given to the choices made.

 

[Snacktime]

37s are easier on the Bronco than 35s. Takes less effort to crawl over obstacles with the bigger tire. If your going to break something your tire is not the reason, it's that right pedal under the steering wheel.

Now wear and tear, directly related to tire size and weight.

 

[CarbonSteel]

37s are easier on the Bronco than 35s. Takes less effort to crawl over obstacles with the bigger tire. If your going to break something your tire is not the reason, it's that right pedal under the steering wheel.

Now wear and tear, directly related to tire size and weight.

Only from a clearance standpoint (extra 3/4") and only if the gearing matches the tire diameter, otherwise, it is not less effort, it is more effort due to the loss of torque from the larger tire.

 

[Snacktime]

Only from a clearance standpoint (extra 3/4") and only if the gearing matches the tire diameter, otherwise, it is not less effort, it is more effort due to the loss of torque from the larger tire.

Math says it takes more effort, right pedal says less effort. Mechanics of have more mass in rotation and not attacking at such a steep angle(bigger tire makes the obstacle smaller per say).

Lot of what works is based off a combination of forces. Static vs in motion plays a key role in wheeling. The secret to wheeling is stay in motion at the correct speed. This is why you bump into an obstacle when you can't make it from a dead stop. 37s are much better suited to the bronco in real world application.

 

[Fordified1]

Prefacing this with a reminder that I have a ‘24 BD non-SAS on order.
So I finally had a chance to see exactly what diffs the 2022 Gladiator I bought about a month ago has under it. It’s a Texas Trail edition which is a mid level trim I would expect to be comparable to a Black Diamond non SAS Bronco. My Gladiator has D44’s front AND rear, 3.73 gears, a rear traction lock, and open front diff.
Why would Ford who openly said they were wanting to one-up the Jeep in every aspect go cheap with the size of the front diff on mid level Broncos? True the Bronco is geared better, but honestly the Jeep wheels just fine anywhere I would want to take it even with 34” tires that it had on it when I bought it, and now I have more confidence in the strength of the front diff.
I have no clue what a Rubicon has under it btw. I’m not a Jeep guy.

As far as street drivability, the Jeep is surprisingly good around town and on 60mph state roads, much better than previous Wranglers I’ve ridden in, BUT a long trip on the interstate flat wears me out with it’s overly assisted twitchy power steering and hard poorly positioned arm rests.

Competition is good but once again, mechanically, Ford kind of brought a knife to a knife fight. I wish they would have brought a gun.

 

[HolidayDog]

Exactly the info I hadn’t been able to find. So what exactly does the 2024 2.3 automatic Black Diamond come with (drivetrain wise) vs adding the SAS package? I already understand the ratio differences and one locker vs 2)

I learned this:
The 24 BD, 2.3 auto has Part Time 4x4 (meaning you need to push a button to switch into 4wd)

The 24 BD 2.3 auto SAS allows the 4A / Automatic 4x4 (the vehicle will automatically switch to 4wd when slippage is detected).....this is ideal for highway/road driving in icy/ snowy climates.

I believe some of the earlier non-SAS BD models have 4A.

 

[swooshdave]

Prefacing this with a reminder that I have a ‘24 BD non-SAS on order.
So I finally had a chance to see exactly what diffs the 2022 Gladiator I bought about a month ago has under it. It’s a Texas Trail edition which is a mid level trim I would expect to be comparable to a Black Diamond non SAS Bronco. My Gladiator has D44’s front AND rear, 3.73 gears, a rear traction lock, and open front diff.
Why would Ford who openly said they were wanting to one-up the Jeep in every aspect go cheap with the size of the front diff on mid level Broncos? True the Bronco is geared better, but honestly the Jeep wheels just fine anywhere I would want to take it even with 34” tires that it had on it when I bought it, and now I have more confidence in the strength of the front diff.
I have no clue what a Rubicon has under it btw. I’m not a Jeep guy.

As far as street drivability, the Jeep is surprisingly good around town and on 60mph state roads, much better than previous Wranglers I’ve ridden in, BUT a long trip on the interstate flat wears me out with it’s overly assisted twitchy power steering and hard poorly positioned arm rests.

Competition is good but once again, mechanically, Ford kind of brought a knife to a knife fight. I wish they would have brought a gun.

Because you don’t benchmark at the mid-level. Price wise how does the BD and Gladiator compare?

 

[Fordified1]

Because you don’t benchmark at the mid-level. Price wise how does the BD and Gladiator compare?

The window sticker from the ‘22 Gladiator says 50k and change. The BD I ordered is close to 53k.

 

[da_jokker]

I learned this:
The 24 BD, 2.3 auto has Part Time 4x4 (meaning you need to push a button to switch into 4wd)

The 24 BD 2.3 auto SAS allows the 4A / Automatic 4x4 (the vehicle will automatically switch to 4wd when slippage is detected).....this is ideal for highway/road driving in icy/ snowy climates.

I believe some of the earlier non-SAS BD models have 4A.

Just to clarify, 4A does not switch TO 4wd. 4A IS 4wd but allows for auto disengagement when binding.

In other words, if you turn on 4A and accelerate, power is sent to both front and rear axles pretty much at all times (as can be viewed by the dash). ..it does not wait until your tires slip.

 

[swooshdave]

The window sticker from the ‘22 Gladiator says 50k and change. The BD I ordered is close to 53k.

All the info I can find says the JL Sport (which is what the Texas Trail is based on) says that they came with the Dana 30 in the front. Only the Rubicon came with the 44 up front.

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