Lifting Blocks and Diff Locks

[baipin]

Hey everyone, new here! Well... new to skoolies and big rigs, but not new to living out of vehicles. :wink1:



I'm wanting to build a rig that can be had for full-time living accommodations for two - so a 40 foot rig at the max, 30 at the minimum. I'd like some mild off-road capability. Nothing remotely crazy like mud or hill climbs or rock crawling, just some dirt trails and unimproved, rutted roads. Maybe a few slightly rocky or rutted sections to get through, but nothing a 2WD truck or AWD car would struggle with... The goal isn't building a rig with constant offroading in mind, it's just getting a bit further out into the wilderness, doing alright in the snow we have up here, and bringing the house along for the ride.



So far, through plenty of talking and reading; it seems like a rear diff locker and more aggressive drive tires are the best two things I could do, to perform well on trails and such.



I've also toyed with the idea of lift blocks to get a bit more clearance - a must on a full length bus, IMO. On one hand I've heard they're flat out illegal and unsafe, yet I know that some Thomas buses came with them stock. (See EastCoastCB's post here: https://www.skoolie.net/forums/f13/bus-suspension-lift-4940.html) There is also an upfitting company in Quebec - Simard Suspensions - that uses them. (https://www.facebook.com/191850504190888/videos/548511109164417)
Finally, this Thomas C2 sold with them today:

So my first question is; it seems that lift blocks are safe and effective if engineered correctly. Is there anything I am missing beyond making sure the pin from the leafs enters into the block, and the block has a pin that enters into the axle? A block milled out of a single block of steel, with holes for the U-bolts, should be just fine I imagine? Am I missing something, and would it be better to find the blocks Thomas used? Could anyone tell me what the serial number is? Would they even bother selling thme to me if I asked?


Second question; are there any buses that come with axles which readily have selectable lockers available for them? Will some buses have axles which cannot be locked, and the axle needs to be switched out for something from a dump truck or whatever? If this is the case, would it be wise to find an Axletech 4000 or Rockwell top-loader for the rear, so it'd be easier to add a front drive axle in the future if I wanted to do a full 4x4 conversion down the road?


Thanks!

 

[Ronnie-SKO]

I generally do not like lift blocks because they twist the springs more, "axle wrap" as it is called. Ladder bars control this. A mild lift of let's say 2" should not be a problem. ECCB has about 4 ". I just do not remember if he has anything to control axle wrap. Been under his bus enough to know but not coming to mind right now.

Locking rears. I do have one in my bus, made by Detroit gear. What is now called a detroit locker.. It is nice to have on mild mud, slick grass, boat launch ramps. Many rears will except one best to check for whatever rear you end up with. Good time to regear if needed as well.

 

[baipin]

I generally do not like lift blocks because they twist the springs more, "axle wrap" as it is called. Ladder bars control this. A mild lift of let's say 2" should not be a problem. ECCB has about 4 ". I just do not remember if he has anything to control axle wrap. Been under his bus enough to know but not coming to mind right now.

Locking rears. I do have one in my bus, made by Detroit gear. What is now called a detroit locker.. It is nice to have on mild mud, slick grass, boat launch ramps. Many rears will except one best to check for whatever rear you end up with. Good time to regear if needed as well.

Thanks for the input! Good point about the axle wrap; I'll look into the ladder bars. I assume those are basically just like traction bars from a pickup? I suppose that'd be pretty simple to fabricate then. All I would be looking for is a lift of about 3", maybe 4" anyways. A little bit of extra ground clearance that's cheap but safe and effective.


As for the lockers; what's the roughest terrain you'd feel comfortable taking yours on?

 

[Jolly Roger bus 223]

why not look at adding airbags and an extra tank if only looking at a mild lift?
but either one a trac bar or ladder is recommended.

 

[Ronnie-SKO]

My biggest concern would be soft mud. So as long as it feels firm I am ok. I have not had any trouble on boat launch ramps even with a 10,000 boat. Logging roads ok again as long as it is not soft mud.

I did get stuck by a creek last summer. It was a nice flat spot but had to back up a hill to get out, and I had a trailer. Rained heavy overnight, and,was raining when I tried to leave. Had to have a tractor pull me out. I was close to another rig and sliding to close to him. If I had more room I would have gotten a bit of a running start and not worried about slip sliding around. Did not help the trailer has surge brakes, so in reverse they set

 

[baipin]

why not look at adding airbags and an extra tank if only looking at a mild lift?
but either one a trac bar or ladder is recommended.

I've explored that too. Do you mean something like helper bags - like these? https://www.sdtrucksprings.com/index.php?main_page=product_info&products_id=7048

I see there are kits for the Durastar and M2. For something older like a GMC B-series or FS65 or International from the 90's - or really any bus - would it just be better to find one with air ride already installed?

My biggest concern would be soft mud. So as long as it feels firm I am ok. I have not had any trouble on boat launch ramps even with a 10,000 boat. Logging roads ok again as long as it is not soft mud.

That all sounds good; that's exactly the terrain I'd want to go on. There are 40,000 km's of documented logging roads in Quebec that I'd love to explore. Many of which should still be accessible by the larger class 8 trucks they were initially designed for. You think traction boards would of helped you? I'm not sure if Maxtrax would be up to the job, but I know the aluminum ones have been used with those MAN expedition trucks... I bet those could be fabricated easily, they're just stamped aluminum after all.

 

[EastCoastCB]

I generally do not like lift blocks because they twist the springs more, "axle wrap" as it is called. Ladder bars control this. A mild lift of let's say 2" should not be a problem. ECCB has about 4 ". I just do not remember if he has anything to control axle wrap. Been under his bus enough to know but not coming to mind right now.

Locking rears. I do have one in my bus, made by Detroit gear. What is now called a detroit locker.. It is nice to have on mild mud, slick grass, boat launch ramps. Many rears will except one best to check for whatever rear you end up with. Good time to regear if needed as well.

the blocks on mine are factory and sort of fit a bit better than just normal blocks. Also mine has full gvwr springs and air ride in the rear. the whole air ride sytem had to be ordered for the 4.5" of lift.

 

[baipin]

My biggest concern would be soft mud. So as long as it feels firm I am ok. I have not had any trouble on boat launch ramps even with a 10,000 boat. Logging roads ok again as long as it is not soft mud.

Well that all sounds good, because that's the exact terrain I'm looking for; Quebec has 40,000 kms of logging roads, many of which are still in good enough condition for the size of rigs we have, seeing as they were built for class 8's initially anyways. Do you think traction boards would've helped you out? Something like Maxtrax, but more like what the big expedition trucks use? Aluminum sand ladders maybe?


https://expeditionportal.com/media/2017/01/Screen-Shot-2017-01-03-at-3.39.01-PM.png

the blocks on mine are factory and sort of fit a bit better than just normal blocks. Also mine has full gvwr springs and air ride in the rear. the whole air ride system had to be ordered for the 4.5" of lift.

Do you have part numbers for those, I think in the other thread you said they were Thomas OEM?

 

[Ronnie-SKO]

Air ride is already set up to control axle wrap. That is what I was forgetting on yours was the air ride.

 

[RamRod4]

There are a few ways to control axle wrap but the design that works best for leaf sprung suspensions is this anti-wrap bar. I ran this on a rock crawler and the benefit is that it doesn't limit your suspension travel/articulation. You can buy kits and weld it yourself.

As for lift blocks, if kept to a non-ridiculous height and pinned like factory blocks, they wont be a problem when coupled with an anti-wrap setup.

Personally, I would look into an air ride setup. A factory setup can easily be modified to allow for height adjustability. Before you look into air ride, you're going to need to make sure there's a locker available for your rear axle. If not, I would look into 5 Ton Rockwell axles as mentioned above. They have good aftermarket support due to being used in rock crawlers and offroad trucks

 

[baipin]

There are a few ways to control axle wrap but the design that works best for leaf sprung suspensions is this anti-wrap bar. I ran this on a rock crawler and the benefit is that it doesn't limit your suspension travel/articulation. You can buy kits and weld it yourself.

As for lift blocks, if kept to a non-ridiculous height and pinned like factory blocks, they wont be a problem when coupled with an anti-wrap setup.

Personally, I would look into an air ride setup. A factory setup can easily be modified to allow for height adjustability. Before you look into air ride, you're going to need to make sure there's a locker available for your rear axle. If not, I would look into 5 Ton Rockwell axles as mentioned above. They have good aftermarket support due to being used in rock crawlers and offroad trucks

Thanks RamRod. What would you consider a non-ridiculous height? Something in the 3" to 4" range?


Should the Rockwells just bolt right up, for the most part? Is spring-to-spring distance fairly standard on trucks of this size?

 

[EastCoastCB]

4" is pretty mild. My bus rides great with its slightly lifted stance.

 

[RamRod4]

Thanks RamRod. What would you consider a non-ridiculous height? Something in the 3" to 4" range?


Should the Rockwells just bolt right up, for the most part? Is spring-to-spring distance fairly standard on trucks of this size?

3-4" shouldn't be an issue. Lots of pickup trucks running around with 4"+ blocks and a 15k gooseneck behind them without issue. Granted, were not talking 40" tall MDT/HDT tires on 22.5" wheels but you get the point. Controlling the axle wrap is what's more important.

Basically, the more lift block you add, the more vertical height separation you're creating between the pinion/yoke and the pivot point (contact surface between block and leaf pack). In other words, your creating leverage that makes axle wrap more pronounced. The anti-wrap bar eliminates that. Also remember that the anti-wrap bar is more effective on one side of the axle vs the other depending on which way your driveshaft rotates. Do a little homework on that before you mount one up.

 

[Ronnie-SKO]

One other point to consider is pinion angle. At 4" lift it is not likely to be an issue unless the last section of driveshaft is short. The more lift the more likely the lift blocks will need to have some taper to them to correct driveshaft geometry.

 

[RamRod4]

One other point to consider is pinion angle. At 4" lift it is not likely to be an issue unless the last section of driveshaft is short. The more lift the more likely the lift blocks will need to have some taper to them to correct driveshaft geometry.

Great point. If it’s a front engine conventional bus of most any length it shouldn’t be too much of an issue since the driveshaft will be pretty long even if it’s a split style with carrier bearing. My rear engine bus has a small driveshaft maybe 3’ long that would need to be addressed if lifted.

 

[baipin]

Yeah, I'd only be looking at a conventional - better ground clearance, better approach angle, and the oil pan isn't the first thing to contact the ground like it would be in a front-engined flatnose bus. SO I imagine pinion angle is less of a worry with that? I've also heard that rear-engines are not good on even very mild offroad - something about weight distribution? A slightly lifted flatnose would look cool though...

 

[coolcraftnet18]

See how well these guys are doing offroad https://youtu.be/-NP3HZ9pwg0

 

[WRS_Mark]

Interesting thread. One item I'd consider if you're going to do any amount of off road adventure, no matter that your plans don't involve anything extreme, is to invest in a set of tire chains. Pair for the back and a steering chain. You may be able to get a set of used units with reasonable life left in them for a steal. Amazing the kind of mess a set of chains can get you out of when you find yourself in the middle of nowhere. Cheers!

 

[Ronnie-SKO]

Interesting thread. One item I'd consider if you're going to do any amount of off road adventure, no matter that your plans don't involve anything extreme, is to invest in a set of tire chains. Pair for the back and a steering chain. You may be able to get a set of used units with reasonable life left in them for a steal. Amazing the kind of mess a set of chains can get you out of when you find yourself in the middle of nowhere. Cheers!

Yes I second that, I have seen logging trucks do it

 

[baipin]

Good idea about the chains, I'll do that!

See how well these guys are doing offroad https://youtu.be/-NP3HZ9pwg0

Awesome, thanks! This is the most helpful video I've seen yet. A locked axle on a bus would do just as well as these guys I imagine. Only difference would be in weight and tires, but everything else looks the same; lots of 6x4 and 4x2 International Durastars and Ford L-series.