Leaf Spring Bushings: Want Rubber, Can't Find Them. Talk Me Into Poly?

Picked up some Iron Rock Offroad 3.5" leafs second hand. Need bushings for them. I really like the idea of sticking with OEM style rubber, but all I can find is polyurethane. IRO said they only have poly and do not have any they can recommend.

Has anybody else dealt with this?

Is this even worth the effort?

Do the IROs not have standard size eyes? Is that why you can't find rubber? Or is it a supply chain issue you are up against?

If it is a matter of the size of the eyes I would call someone like National Spring or Deaver and ask them if they have information about which factory style rubber bushings would fit the IRO spring eyes (of course have specs in hand for the IRO spring eyes before you call).

If it is a matter of supply chain I would keep looking. Parts will come back in stock, once they finally get off the ships and onto trucks.

I do think it is worth the effort. Unless you don't mind listening to squeaking bushings.

Anak said:

Do the IROs not have standard size eyes? Is that why you can't find rubber? Or is it a supply chain issue you are up against?

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The IRO springs have 2" diameter eyes. Different than OEM.

Anak said:

If it is a matter of the size of the eyes I would call someone like National Spring or Deaver and ask them if they have information about which factory style rubber bushings would fit the IRO spring eyes (of course have specs in hand for the IRO spring eyes before you call).

Click to expand...

That's a decent idea. I tried looking through the Dayton catalog but at 1,000+ pages of unsearchable pdf I didn't get far. I suppose I haven't put in the leg work to determine the size I need.

AFAIK, the OEM sizes are:

Front:
OD: 2.500"
ID: 0.563"
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 3.188"

Rear:
OD: 1.750"
ID: 0.563"
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 2.750"

Hopefully can find some that match those dimensions with a 2" OD. I was searching on TruckSpring.com, which has a decent search filter by size, but didn't find any that work.

Anak said:

I do think it is worth the effort. Unless you don't mind listening to squeaking bushings.

Click to expand...

Thanks for supporting this. I thought everyone would say just go poly because its easy. The squeak isn't even the number one driving factor of me wanting rubber, although its up there. I can't wrap my head around the idea of a poly bushing being good for decoupling the springs from the body, and also handling the torsional deflection as well as rubber can. I would think rubber should ride better and flex better, maybe at the expense of shorter longevity.

The only downside I can see to rubber is how the inner sleeve is bonded to the rubber, so when a leaf droops it twists the rubber axially. I can't imagine they would hold up very well to that. I'd love to see a robust rubber bushing with good flex characteristics come to market, but I'm not holding my breath for any new leaf spring products.

I'd be very curious to try Orbit Eyes or another style joint in a leaf spring bushing, but I don't like how those style joints don't self-center. I feel there would be a big loss in lateral stability without that. I'm looking to get new shackles with these leafs and have been eyeballing Boostwerks' Comp Shackles with the Ballistic Joints at the frame side, but I'm not sold. My rig sees too many road miles to compromise pavement characteristics. I'm gonna send him a message to ask about his experience. I don't want to do a panhard or anything of that nature.

Try Husky Spring.

XJlimitedx99 said:

AFAIK, the OEM sizes are:

Front:
OD: 2.500"
ID: 0.563"
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 3.188"

Rear:
OD: 1.750"
ID: 0.563:
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 2.750"

...

The only downside I can see to rubber is how the inner sleeve is bonded to the rubber, so when a leaf droops it twists the rubber axially. I can't imagine they would hold up very well to that. I'd love to see a robust rubber bushing with good flex characteristics come to market, but I'm not holding my breath for any new leaf spring products.

Click to expand...

Those specs are good information to work from. The inner sleeve width would be the one dimension where I think you may have some flexibility. If the inner sleeve width is smaller you could probably add spacers on each side and make up for the reduction. Just keep the spaces of a relatively small diameter so they don't interfere with flexing.

With regard to the bond between the rubber and the sleeve, I doubt you will find that to be much of a problem. I don't think there is a great amount of movement (in degrees of rotation) at the spring eye. Certainly not any worse than happens with front A-arms, and I believe the bushings in A-arms are similarly bonded (I am thinking of my Chevy trucks).

Best of luck with the search. My suggestion of spring companies was for the sake of trying to spare you a search through a painful list of parts.

Do the IRO leaf packs have 2" diameter bushing holes on both ends?

I have RC leaf packs, and they also use a non-standard bushing hole at the rear end of the leaf pack. I ended up making a pair of urethane bushings work. No obvious increase in noise or squeaks since installing about six months ago. I used a lot of the silicone grease.

Thank you for the recommendations everyone. I just sent off a few emails. We'll see if I get anything good back over the next few days. I'll let you know.

maxbraketorque said:

Do the IRO leaf packs have 2" diameter bushing holes on both ends?

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Yes, same on both ends.

XJlimitedx99 said:

Talk Me Into Poly?

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I like poly. It's more durable, makes for better handling,
and is easier to install. If you use silicon grease when
installing, there'll be no squeaks.

I've replaced several rubber bushings with poly in the wife's
Explorer, with good results. I consider it an upgrade....

Does anybody know if the Alcan springs use the same size bushings as stock or other known brand. I want to order some and change them out when I swap in my custom width D44.

Don't know if this will help:
https://www.stengelbros.net/Leaf-Spring-Bushings_c_408.html

XJlimitedx99 said:

Picked up some Iron Rock Offroad 3.5" leafs second hand. Need bushings for them. I really like the idea of sticking with OEM style rubber, but all I can find is polyurethane. IRO said they only have poly and do not have any they can recommend.

Has anybody else dealt with this?

Is this even worth the effort?

Click to expand...

I have IRO leafs with poly bushings and they occasionally squeak a little, but not enough to annoy me.

Just wanted to follow up on this with my findings and current experience. I have removed my leafs and measured the original bushings to confirm these are the OEM bushing specs:

XJlimitedx99 said:

Front:
OD: 2.500"
ID: 0.555" (M14 clearance)
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 3.188"

Rear:
OD: 1.750"
ID: 0.555" (M14 clearance)
Outer Sleeve Width: 2.500"
Inner Sleeve Width: 2.750"

Click to expand...

I ordered Dayton RB-121 bushings for the front, and RB-130 for the rear.

The rear bushings look like they'll work great. They match the OEM specs with the 2" OD that I need and the only difference being they are .563" ID for a 9/16" clearance hole. Should work out just fine.

The front bushings are only 3.125" wide vs the OEM 3.188", so I'll either need to use a washer or get some different bushings.

Thanks for posting the factory bushing dimensions. Always good to have that kind of info.

Nobody uses rubbers anymore wtf are you thinking?

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Evan03 said:

Nobody uses rubbers anymore wtf are you thinking?

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Click to expand...

How about every OEM vehicle that rolls off the lot?

What do they know? They own the runber factory. im joking but it is probly the easiest cheapest method thats been in place for a thousand years.

Rubber is Definitely not as resistent to oils as poly but there shouldn't be a large oil volumn in the spring eyes.

I run poly in my leaf springs and shackle only lube them with water and dirt the run quite.

On the front I do have lots of noise from dual rate springs poly bushings mixed with heim joints. She talks alot.

The poly bushings I fabbed on lower control arms have grease zerks they been running grease since new and tslking the hole time. I almost wonder if the grease makes them make noise. Ive gotten used to it. Grease every ride depending on whos riding with me

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