IFS feedback wanted

richfroh said comments from the peanut gallery ... but bring it on!  

Peanut gallery checking in...

I probably know less than every other person in this group, but:

are you sure you want/need a front locker? I think you can do a lot with just a rear locker (assuming proper gearing, 37" tires, etc etc).

buckallred said I probably know less than every other person in this group, but: are you sure you want/need a front locker? I think you can do a lot with just a rear locker (assuming proper gearing, 37" tires, etc etc).  

I currently have a rear limited slip that works well. I would add a selectable front locker and eventually a rear locker.

Reasons for staying at 35s or going to full SAS are as follows:

Your front axle is a 31 spline reverse cut 8.8" with an aluminum housing.  The 31 spline axles are 1.32" in diameter and are approximately the same as the 1.31" diameter 30 spline dana shafts in a Dana 44.  (compare this to 1.5" 35 spline on 1ton axles) The shaft alone limit Jeeps and smaller rigs to 37s but you truck is 5,400lbs empty vs 3,400lbs empty for a TJ.  If you are going to 37s then carry a spare shaft and know how to replace it on the trail.

Being a CV shafts mean that the more angle the shaft is under, the more stress the joints will be under.  RCVs would live fine but the IWE actuators would need to be replaced with sleeves (if your truck is equipped with the IWE system) and the RCV cost alone is more expensive than a junkyard Dana 60, gears, and a locker.

The gears themselves, being reverse cut high-pinion 8.8" are plenty for 37s but the aluminum housing will have more flex than a cast steel unit.  Ford put a torsen limited slip in the raptor front because there is still some give in the unit without sacrificing much traction in dirt over a full locker.  Following this logic, a Detroit true-trac would be a better choice increasing traction without fulling loading the differential (if they are available).  Adding a locker is about the same stress as ~2" bigger tires.

On top of all of that, you have ball joints, a-arms, steering knuckles, and steering which will see increased loading.

Another option to increase the survivability of the front IFS would be to lighten the rig.  Bob the bed, half doors, etc.

Thanks for the input Kris.

As a little background, I went to On The Road Trucks and talked to them about my options. They said the best option is a SAS, but said it would be difficult because of the way the frame kicks in at the front. They looked at options and gave me a rough ballpark of $10,000 to $15,000 to have them do it, because of the amount of custom fab that would be required.

You are right about the 8.8 aluminum housing being a weak point, but it is not a high pinion. Also, the only selectable locker for it right now is the ARB. The RCV CV shafts are over $2,700. They are guaranteed for life for tires up to 47" which is great, but does not help the aluminum housing. There are stronger upper and lower control arms available as well as outer tie rod ends. I would be concerned about the strength of the rack & pinion.

Why would the IWE actuators need to be replaced with sleeves? Yes , my truck is equipped with them.

I don't have much of a budget for these mods yet but I do want to increase the capabilities of my truck. I also don't want to spend a bunch of money on upgrades and throw it away later if I do an SAS.

One of my thoughts was to fab up a Dana 60 as a bolt in replacement for the stock 8.8, use RCV CV shafts and upgrade all the control arms. It would probably need a custom power steering box system to replace the rack and pinion at that point. I'm probably at the same point price-wise as a SAS, but the upgrades could be done piece by piece over time. Remember, this is my daily driver so I can't have it disabled for too long.

I'm not opposed to doing a SAS at home (with some skilled help) but what would be involved, assuming I am willing to source parts from salvage yards to keep costs down? Would I need to use leaf springs or could I use coilovers? With the frame kicking in at the front, I don't know how leaf springs would mount or how the 4-links would mount.

Finally, my reasoning for wanting to go with bigger tires is for much needed ground clearance due to the long wheelbase, and to help clear the IFS cross members and rear diff.

I'm all for SAS.  You could make leaf springs work.  You would just need a front cross member.  Coilovers is a great option but much more expensive.  I would poke around and see if you can find any SAS f150s in your year already and see what they have done.

You would need a new steering box and make sure that a straight axle will fit below the motor without going too tall on the lift.

$10-15k seems low honestly, even for doing it all yourself.  There is a ton of labor involved even in the most simple leaf based SAS swap.  You have a big truck and want to run big tires, you will need a big budget.  Here is an example of how a quality fabrication shop does it right. (page 2 shows the estimates and costs... $$,$$$)

https://www.ford-trucks.com/forums/1061812-out-with-ifs-in-with-sas-on-2008-ford-f-150-a.html

To do a custom IFS kit capable of handling 37"+ on the trails we run with a rig as big and heavy as yours, you are easily double the cost. (think race truck budget)

37"+ aren't a great choice for a daily driver and doing a custom suspension isn't going to help reliability as a daily driver.  Since you a concerned about $, have you considered selling the f150 and getting something that is better suited for the task at hand?

To address your paragraphs in order:

ORT is correct that the SAS is the best option to achieve what you want. Their estimate seems low to me.

Im 95% certain that f150s never had a low pinion front end over any of the generations, but only 95%.

IWE actuators are basically vacuum lockout hubs, they fail.  RCV and others sell solid sleeves, essentially drive slugs.  Eliminates the weak moving part but adds wear to your CV shafts but not ideal for a daily driver. (pros and cons everywhere)

There are other modifications you could do now to improve the capability that wouldn't be out the window in the event of an SAS swap. Bumpers, sway bar disconnects, and skid plates are the big ones and bobbing the bed is another option.

Custom ISF is easily double $ of SAS when said and done and also less capable when rock crawling which is all difficult trails in the sierras.

SAS, though straightforward, it still a ton of work.  Trucks like toyotas and older TTB fords have aftermarket support and kits that make them weekend projects.  You will be looking at more downtime than would be acceptable with a daily driven rig and a lot of custom parts because there isnt any aftermarket support yet.  Junkyard axles maybe but most of the other parts would be new or custom.  Leaf sprung SAS is always simpler but coilovers will be smoother.  The frame kicking in is honestly the easiest thing to deal with compared to oil pan clearance, driveline angles, steering and track bar interference, etc.

That is a good reason for going to bigger tires.  But you actually wheel your rig so unless you plan to stick to the mall parking lot you will need to beef up the axles to support them.

Gregulator said I'm all for SAS.  You could make leaf springs work.  You would just need a front cross member.  Coilovers is a great option but much more expensive.  I would poke around and see if you can find any SAS f150s in your year already and see what they have done. You would need a new steering box and make sure that a straight axle will fit below the motor without going too tall on the lift.  

I have looked and have not heard of any 2010 F150's with a SAS. OTR has not seen any either.

Just looking by eye, a straight axle should fit under the engine with no problems.

kris_olof said

37"+ aren't a great choice for a daily driver and doing a custom suspension isn't going to help reliability as a daily driver.  Since you a concerned about $, have you considered selling the f150 and getting something that is better suited for the task at hand?  

Not considering selling the F150! I love the truck, and I need the capabilities of a pickup and tow rig.

kris_olof said There are other modifications you could do now to improve the capability that wouldn't be out the window in the event of an SAS swap. Bumpers, sway bar disconnects, and skid plates are the big ones and bobbing the bed is another option

That is a good reason for going to bigger tires.  But you actually wheel your rig so unless you plan to stick to the mall parking lot you will need to beef up the axles to support them.  

Bumpers, sway bar disconnects, and skid plates are all on the list regardless of which suspension I run. Bobbing the bed or swapping to a custom flatbed are possibilities, but not until I sustain more damage to the existing bed.

I know I need to beef things up, that's why I asked for input so I could formulate a game plan.

Another thing that puts a damper on my plans is a wife who thinks I go wheeling to try to break my truck. She just doesn't get it. Therefore, fixing things that are broken or worn out might be ok with her, but spending money on parts that are not broken does not make sense to her.

Peanut gallery... wait a year and get a JLT!

k-jeep said Peanut gallery... wait a year and get a JLT!  

I'm all about you keeping your Ford Rich, I think it's great.  I want to poke around some more at other options before I give you more opinions.  But I would encourage you to contact WFO and see what they think of the swap to straight axle.  They have done numerous newer style trucks.  I think mainly GMC and Chevy, but they may have some insight.  Anything is possible with enough money and grit.

kris_olof said $10-15k seems low honestly, even for doing it all yourself.  There is a ton of labor involved even in the most simple leaf based SAS swap.  You have a big truck and want to run big tires, you will need a big budget.  Here is an example of how a quality fabrication shop does it right. (page 2 shows the estimates and costs... $$,$$$) https://www.ford-trucks.com/forums/1061812-out-with-ifs-in-with-sas-on-2008-ford-f-150-a.html   To do a custom IFS kit capable of handling 37"+ on the trails we run with a rig as big and heavy as yours, you are easily double the cost. (think race truck budget)   37"+ aren't a great choice for a daily driver and doing a custom suspension isn't going to help reliability as a daily driver.  Since you a concerned about $, have you considered selling the f150 and getting something that is better suited for the task at hand?  

The shop that did that swap is top of the line fab work in the JK world.  I'm not surprised how much it cost.  That's not far off from having them build you a JK either.  Top of line axles, suspension and steering.

Kris, if it were all about great choices, I think most of us wouldn't be four wheeling...Spend lots of money to alter factory engineered vehicles to have worse handling and terrible gas mileage. LOL!  It is silly what we do when you take a step back and look at it.  But I will say I don't regret going to 40s on my daily driver.  😎

Gregulator said I'm all about you keeping your Ford Rich, I think it's great.  I want to poke around some more at other options before I give you more opinions.  But I would encourage you to contact WFO and see what they think of the swap to straight axle.  They have done numerous newer style trucks.  I think mainly GMC and Chevy, but they may have some insight.  Anything is possible with enough money and grit.  

Thanks Greg, let me know if you discover more options. I'll contact WFO when I get a chance. I have more grit than money, and the list of things I need to upgrade or modify grows faster than I can work on it.

kris_olof said 37"+ aren't a great choice for a daily driver  

The Raptors come with 35" (actually 34.5"😉 tires from the factory, so going up to 37" is not much of a step. The front diff is the same as the F150 but adds the Torson limited slip. The F150 control arms should see less load than the Raptor because they are shorter than the Raptor's. I agree that bigger tires will add stress to parts, but stepping up 2" over factory offerings is not excessive. Am I overlooking something?

richfroh said

Thanks Greg, let me know if you discover more options. I'll contact WFO when I get a chance. I have more grit than money, and the list of things I need to upgrade or modify grows faster than I can work on it.  

Rich, I admire your grit more than I admire money. I'm always impressed with what you do out on the trail with your rig. Some people might think you're crazy, including me at times, but what you do with your truck is a testament to your passion to off-road. Love it!