Suspension bolts

[TedS]

I think I would opt for an independent suspension if I were to need or want to change suspensions. We had good experience with the torsion bar system on our power unit trailers. Of course they were lighter and single axle. Still, they seemed to be very robust.

[ajg617]

I think I would opt for an independent suspension if I were to need or want to change suspensions. We had good experience with the torsion bar system on our power unit trailers. Of course they were lighter and single axle. Still, they seemed to be very robust.

Yes, I'd love to schedule IS install while we are in Elkhart. Just don't know how long GD is going to have the coach. They are doing front flex measurements, a complete suspension inspection and R&R, and a number of other items and it really depends on what they find.

[Cate&Rob]

nprario Hi Nels,

Could you post some more detailed pictures of your trac bar installation? Particularly how it attaches to the axle tube and the frame rail.

When Pat Gyrogearloose and I were working on this idea, we were concerned about clamping to the thin wall axle tube and twisting the frame rail with our bolt on idea there. Your thicker wall axle tube has solved one of these concerns and the bar welded across the hangers has solved the other.

More details on your installation would be great. BTW . . . I think this is a great idea for controlling cross axle loads and movement.

Rob

[Tophermiller]

Could you post some more detailed pictures of your trac bar installation? Particularly how it attaches to the axle tube and the frame

I think this is a great idea for controlling cross axle loads and movement.

Rob

Can someone argue the virtues of a trac bar versus the Morryde X-factor bars? Do they address the same or different needs? And which works better?

[nprario]

[Yoda]

Question for folks. Having read oll of this I went searching for GRADE 8 wet bolts 3.4" long. I have yet to find them. So I am asking if anyone knows of a source. I want a few for the oop's parts kit. Or for my lighter trailer is the grade 5 all I need? I have several sources for those including Dexter. Lippert and MorRyde. I need the 3.4" due to the X=Factor cross bracing.

Thoughts?

Happy Thanksgiving - the one day a year you can tell someone to get stuffed and smile

Keith

[Cate&Rob]

Yoda

Copied from the internet (so . . . it must be true, right? )
"Grade 8 fasteners are made of high-strength alloy steel and are heat-treated to increase their strength. However, this heat-treatment process can also make them more brittle, which can increase the risk of fastener failure"

However, this has always been my understanding. In a trailer suspension application, I do not think a Grade 8 bolt offers an advantage over a Grade 5. (Just my opinion)

Rob

[Cate&Rob]

Can someone argue the virtues of a trac bar versus the Morryde X-factor bars? Do they address the same or different needs? And which works better?

A track bar cross braces the axle to the frame. Without this, the side loads and sideways motion of the axle (most easily observed when backing the trailer) are resisted only by the springs and links. which are designed primarily to handle vertical loads.

Cross bracing the hangers (such as with the MORryde X Factor) resists sideways bending of the hangers but does nothing to assist the suspension in maintaining crosswise axle position.

Rob

[Cate&Rob]

nprario Hi Nels,

Thanks for the detailed pictures! Do you know which parts were fabricated and which were sourced?
The attachment clamp to the axle tube is identified as "TT" . . . but I can't find anything like this on the internet.

Rob

[Jlawles2]

Cate&Rob Rob I found these by searching Trailer axle clamp: https://www.summitracing.com/parts/a...kaAmCsEALw_wcB I like the double bolt one.

I wonder if it would be acceptable to use the U-bolts on the leaf spring instead? This also lowers the angle on the bar meaning less side shift per vertical movement.

Found the MFG site: https://allstarperformance.com/clamp...wide-all60147/

[TedS]

Yoda

Copied from the internet (so . . . it must be true, right? )
"Grade 8 fasteners are made of high-strength alloy steel and are heat-treated to increase their strength. However, this heat-treatment process can also make them more brittle, which can increase the risk of fastener failure"

However, this has always been my understanding. In a trailer suspension application, I do not think a Grade 8 bolt offers an advantage over a Grade 5. (Just my opinion)

Rob

Kind of a myth, the brittle idea. Higher strength means stronger. The breaking strength of gr8 is higher than the stress where gr5 bends. True that gr8 breaking strength is closer to its ultimate strength than is gr5's. Where gr5's yield, gr8's hold together. Gr5 yield is 72000psi, gr8 yield is 90000psi.

[nprario]

nprario Hi Nels,

Thanks for the detailed pictures! Do you know which parts were fabricated and which were sourced?
The attachment clamp to the axle tube is identified as "TT" . . . but I can't find anything like this on the internet.

Rob

They manufacture all the pieces at their shop. TT stands for Tru Trac which is what they call their system.

[Yoda]

A track bar cross braces the axle to the frame. Without this, the side loads and sideways motion of the axle (most easily observed when backing the trailer) are resisted only by the springs and links. which are designed primarily to handle vertical loads.

Cross bracing the hangers (such as with the MORryde X Factor) resists sideways bending of the hangers but does nothing to assist the suspension in maintaining crosswise axle position.

Rob

So I understand. The X-Factor is only resisting movement of the hangers by tying them together, but will not prevent the twisting of the springs and sideways axle movement. The Track bar will prevent the spring twisting and axle movement, but will it prevent the hanger movement.?

In the photos the backing brace is attached to the inside hanger face at each location and not the frame. The reason I say this in the 4th picture of the rear section of the brace you can see the coroplast visible. nprario is this correct that the backing brace is attached to the hangers?

I have two thoughts - yes I know that is dangerous for me.

First with thin wall 3" tub (most GD units have 3" tubing) like I had, I believe the clamp would bend the tube given the angled force and locking method of the clamp. I think Joseph Jlawles2 idea of attaching to the spring U-Bolts is probably better than the axle tube. I assume he is thinking of some sort of plate attached to the U bolts with the pin mount.

Second with the backing 2x2 square brace attached to the hangers, is not additional side stress being applied. I do see the hanger have been installed, but this will put a lot of twisting load on the flange and possibly end up fatiguing the frame web in these locations similar to my frame cracking.

nprario did they do any frame stiffening not shown in the photos? Please don't get me wrong I am sure the Tru Trac folks have this all figured out. But I had major fram cracks after driving to Alaska caused by the flange twisting the web. Lippert had inadequate and improper stiffining at the hangers by attaching gussets to the center of the web from the lower flange at the hangers.

Now I am sure I am missing something here as I am not the best at structural design and do not have a clue when it comes to car suspensions with track bars.other than they corner better and can go faster.

Thanks for letting me chime in - or do I need to go back to my corner and add the dunce cap this time

Keith

[nprario]

So I understand. The X-Factor is only resisting movement of the hangers by tying them together, but will not prevent the twisting of the springs and sideways axle movement. The Track bar will prevent the spring twisting and axle movement, but will it prevent the hanger movement.?

In the photos the backing brace is attached to the inside hanger face at each location and not the frame. The reason I say this in the 4th picture of the rear section of the brace you can see the coroplast visible. nprario is this correct that the backing brace is attached to the hangers?

I have two thoughts - yes I know that is dangerous for me.

First with thin wall 3" tub (most GD units have 3" tubing) like I had, I believe the clamp would bend the tube given the angled force and locking method of the clamp. I think Joseph Jlawles2 idea of attaching to the spring U-Bolts is probably better than the axle tube. I assume he is thinking of some sort of plate attached to the U bolts with the pin mount.

Second with the backing 2x2 square brace attached to the hangers, is not additional side stress being applied. I do see the hanger have been installed, but this will put a lot of twisting load on the flange and possibly end up fatiguing the frame web in these locations similar to my frame cracking.

nprario did they do any frame stiffening not shown in the photos? Please don't get me wrong I am sure the Tru Trac folks have this all figured out. But I had major fram cracks after driving to Alaska caused by the flange twisting the web. Lippert had inadequate and improper stiffining at the hangers by attaching gussets to the center of the web from the lower flange at the hangers.

Now I am sure I am missing something here as I am not the best at structural design and do not have a clue when it comes to car suspensions with track bars.other than they corner better and can go faster.

Thanks for letting me chime in - or do I need to go back to my corner and add the dunce cap this time

Keith

Yes they tie in all the spring hangers with the square tube. No extra frame gusseting. Mine being newer does have extra gussets above the equalizer hangers and the V plates already welded on the frame.

[Yoda]

Yes they tie in all the spring hangers with the square tube. No extra frame gusseting. Mine being newer does have extra gussets above the equalizer hangers and the V plates already welded on the frame.

Nels
Thanks for filling in the extra information. Starting to make sense to the old fogy now.

Keith