Why Did They Choose Independent Suspension For 2021 Bronco? - Engineering Explained

[Rick Astley]

Tire width is important for drag, but there is more to it than that. Larger diameter effectively reduces gear ratio, so the engine has to work harder to get the truck moving and keep it rolling. Heavier tire and wheel combos are increased rotational mass that must be moved to accelerate, brake, and steer. Rotational mass has a multiplier of 2:1 for tires and 1.6:1 for wheels compared to regular vehicle weight, so adding 40# on all 4 tire and wheel assemblies (160#) is like adding close to 300# on the truck for acceleration and braking purposes. On other forums (Tacoma) guys are reporting a significant difference in feel, power, and mileage when changing the wheel combo by as little as 10 pounds.

I’m guessing there will be some skinny tire threads on here soon if there aren’t already. 255/85R16 will find their was onto a lot of base Broncos, and 255/80R17 on many others. The only problem with the skinny tires is they are all E rated. The E rating means they are heavy, so they weigh about the same 53# as a 285/70R17 BFG AT.

You...... Get out of here with that wisdom, knowledge and desire to help other people out!!!! How do we report this sort of post to the moderators so nobody has to be offended?

It always shocks me how many guys are so excited to slap on an extra 40 lbs at each corner with no thought to braking requirements or how they are actually hurting all aspects of performance/drivability except off-road performance (while driving on-road 99% of the time)

Where can I get that Powder Blue in the video @12:58? That was gorgeous

You can get Lightning Blue on almost any 2018-2020 Ford product. We love it on our 2019 Ranger Lariat FX4! Once you have the Lightning Blue, then Velocity just can't match the depth or color. My Bronco will be Race Red.

17x8.5” Raptor beadlocks for the Gen 2 are 36.8# each with the fake rings, lock rings added a few more pounds. The 17x8.5 non beadlock are 31.5# last I checked. Some guys were chasing aftermarket wheels that were 24-26#. If I kept mine that was the direction I would’ve gone.

45# seems light for the Goodyear’s in a LT285/70R17, but that is what they show on Tire Rack. The stock BFG’s should be 52#, the Falken AT3W are 63#, and some P rated tires are 41-43#. I could certainly see getting the Cooper 4S at 43# in the future, but if the 45# number on the Goodyear is accurate I might consider changing my order to get them.

I'll be going with steelies when it's time to get a dedicated set of 35" off road tires for many reasons, one is weight, another is the ability to correct a bead with a hammer on the trail. You can get nearly any size steelie custom made to your backspacing, offset, etc for quite a bit less than these cast wheels.

Sponsored

 

[jjack50]

Tire width is important for drag, but there is more to it than that. Larger diameter effectively reduces gear ratio, so the engine has to work harder to get the truck moving and keep it rolling. Heavier tire and wheel combos are increased rotational mass that must be moved to accelerate, brake, and steer. Rotational mass has a multiplier of 2:1 for tires and 1.6:1 for wheels compared to regular vehicle weight, so adding 40# on all 4 tire and wheel assemblies (160#) is like adding close to 300# on the truck for acceleration and braking purposes. On other forums (Tacoma) guys are reporting a significant difference in feel, power, and mileage when changing the wheel combo by as little as 10 pounds.

I’m guessing there will be some skinny tire threads on here soon if there aren’t already. 255/85R16 will find their was onto a lot of base Broncos, and 255/80R17 on many others. The only problem with the skinny tires is they are all E rated. The E rating means they are heavy, so they weigh about the same 53# as a 285/70R17 BFG AT.

Tire width is important for drag, but there is more to it than that. Larger diameter effectively reduces gear ratio, so the engine has to work harder to get the truck moving and keep it rolling. Heavier tire and wheel combos are increased rotational mass that must be moved to accelerate, brake, and steer. Rotational mass has a multiplier of 2:1 for tires and 1.6:1 for wheels compared to regular vehicle weight, so adding 40# on all 4 tire and wheel assemblies (160#) is like adding close to 300# on the truck for acceleration and braking purposes. On other forums (Tacoma) guys are reporting a significant difference in feel, power, and mileage when changing the wheel combo by as little as 10 pounds.

I’m guessing there will be some skinny tire threads on here soon if there aren’t already. 255/85R16 will find their was onto a lot of base Broncos, and 255/80R17 on many others. The only problem with the skinny tires is they are all E rated. The E rating means they are heavy, so they weigh about the same 53# as a 285/70R17 BFG AT.

Of course we also have to remember that comparing an 18 vs a 17 doesn’t necessarily mean that are different in overall diameter.

 

[Mr. Nice]

17x8.5” Raptor beadlocks for the Gen 2 are 36.8# each with the fake rings, lock rings added a few more pounds. The 17x8.5 non beadlock are 31.5# last I checked. Some guys were chasing aftermarket wheels that were 24-26#. If I kept mine that was the direction I would’ve gone.

45# seems light for the Goodyear’s in a LT285/70R17, but that is what they show on Tire Rack. The stock BFG’s should be 52#, the Falken AT3W are 63#, and some P rated tires are 41-43#. I could certainly see getting the Cooper 4S at 43# in the future, but if the 45# number on the Goodyear is accurate I might consider changing my order to get them.

I totally agree. A lot of folks never consider the tires weight. Thats a big mistake because of the all around performance benefits. That is one reason why I ordered the MT's. I also really prefer the look and their larger diameter over the K02's.

I would like to possibly change over to a good 285/75/17 someday and that might be the perfect blend if these MT's are not. The 315's or wider don't accommodate the roads as well.

 

[TXNavy]

You can get Lightning Blue on almost any 2018-2020 Ford product. We love it on our 2019 Ranger Lariat FX4! Once you have the Lightning Blue, then Velocity just can't match the depth or color. My Bronco will be Race Red.

I agree that Lightning Blue is a beautiful color and that having to settle for VB will always be a small grit in my teeth.

However did you watch the video at the timestamp I quoted (12:58)? That is a powder blue almost like Brittany Blue and also looked awesome. I'm wondering if anybody knows where that part of the video was shot and if it was part of a concept build that I didn't know about.

 

[Dimitar]

Great review

 

[Dr.Detroit]

This is great YouTube channel if you haven't seen any of his videos!

I agree this guy did a great job!

 

[MaverickMan]

Why Did They Choose Independent Suspension?
No Death Wobble

Because the 1979 Bronco was too rough. The real question is why didnt Ford use I beams?

 

[fschael]

As an Austin resident who knows the roads and route he's taking from downtown out west very well, I can completely understand the garbage mpg's he's getting. It's constant traffic and 45-60 mph speed limit roads with tons of stoplights, breaking on down hills, and accelerating through steep uphills. Even feather footing our stock 4dr wrangler JK around here in west Austin, we can't climb above an average of 16 mpg (and its rated for 16-20 cty/hwy). Our stock wrangler would average about 14 mpg or worse on the route he's taken with his slightly spirited driving, so not much better than the 12.7 mpg he's reporting. Sure, I've gotten 19 mpg on single trips to HEB and back with light traffic and not hitting many lights, but that's hard to achieve and requires a lot of coasting.

TLDR: take his current fuel economy rating with a HEAVY grain of salt.

For those out of state folks that for some reason is asking to them self "what on earth is HEB", well is just a piece of heaven that we have over here and visit it at least once a day, after work mostly.

P.S. Sorry Dallas, you can feel out of state on this one.

 

[Efthreeoh]

Because the 1979 Bronco was too rough. The real question is why didnt Ford use I beams?

Un-sprung mass and forged aluminum lower control arms are cheaper to make in 2021 vs. pressed steel in 1985 is my guess.

What my real question is, why didn't Ford use an independent rear suspension on the Bronco with the fancy auto swaybar?

 

[88to21bronco]

2.7 4dr. Driving with the soft top in the first position so more drag. Driving 59 mph and 74 mph with cruise, with a mix of city driving thrown in. Even had to pass a few slowpokes on the highway.

 

[dgorsett]

Un-sprung mass and forged aluminum lower control arms are cheaper to make in 2021 vs. pressed steel in 1985 is my guess.

What my real question is, why didn't Ford use an independent rear suspension on the Bronco with the fancy auto swaybar?

Because then instead of one wheel off the ground frequently there would be two. Driving a four wheel IS vehicle off road can make you a bit dizzy.

 

[dgorsett]

Because the 1979 Bronco was too rough. The real question is why didnt Ford use I beams?

I've owned five TTB vehicles and found them to be superior off road and fine on road. They have a bad rep though, mainly from alignment issues with overloaded 3/4 tons IMHO.

 

[MaverickMan]

I have only had 3 TTB 4x4s and have been pleased with their performance in stock or near stock form. Also they have a great turning radius. I have had 8 2wd I beam vehicle and loved how they handled especially when abused( jumping!) always felt confident turning 7000lb vans alot faster than Ford intended. I really think the concept should be revisited. I recently saw an TTB Jeep XJ that could really rip. I'd love to build my AMC Eagle with TTB. I wonder how TTB would work in IRS aswell. That would be really interesting in a speedy offroader.

Sponsored