Ron Sutton Offset 3-Link install

[XTRMEASURES]

Great thread and great looking 3-link design. I'm glad i stumbled on it, ive being trying to deside on a rear suspension for my truck for about a year and a half. And i think this would give me both street/autocross performance without cutting or welding on the truck. Very inspirational and thanks for posting.

Oh and PS Mr. Ron Sutton for President!!!!!

[XTRMEASURES]

Not sure if it's been mentioned but what size heim joints are used on the 3-link?

[Ron Sutton]

Originally Posted by XTRMEASURES

Not sure if it's been mentioned but what size heim joints are used on the 3-link?

The 3-link rod end sizes are 3/4" x 3/4" and 3/4" x 5/8". Mild steel economy 2-piece rod ends would probably be OK but I can't bring myself to use them. There are 3 versions of chromoly rod ends. I use them all for different applications:
#1. Black lower cost versions that are the same size & shape as economy mild steel rod ends. Great value & extra piece of mind for a small price. These run no liner & need to be cleaned & lubed often. Zero stiction.

#2. Wide body 3-piece precision rod ends are the most expensive. The 3rd piece is a precision race that is pressed into the body. These run no liner & need to be cleaned & lubed often. Zero stiction.

#3. Wide body 3-piece precision rod ends with a Nylafiber race liner. The Nylafiber race liner is injected into the body. These are self-lubricated & self wiping, so they keep a high degree of grit off the wear surface of the ball. They don't require cleaning & lubrication often. About 1 pound of stiction.

Here are the radial load ratings & costs for comparison:
3/4" x 3/4" Economy Mild Steel: 18,810# (Cost $12)
3/4" x 3/4" Economy Chromoly: 25,000# (Cost $17)
3/4" x 3/4" Wide Precision Chromoly: 28,081# (Cost $33)
3/4" x 3/4" Wide Nylafiber Liner Chromoly: 28,081# (Cost $26)

3/4" x 5/8" Economy Mild Steel: 19,350# (Cost $12)
3/4" x 5/8" Economy Chromoly: 27,000# (Cost $17)
3/4" x 5/8" Wide Precision Chromoly: 40,572# (Cost $33)
3/4" x 5/8" Wide Nylafiber Liner Chromoly: 40,572# (Cost $26)

For low budget applications, I use & recommend the black economy Chromoly rod ends. The price is so close to mild steel & the strength is a big increase.

Both wide body Chromoly rod ends have the same shape, dimensions, materials & load ratings as each other. The body is almost twice as wide as the economy rod ends. I use these in all my race cars, Track-Star & AutoX-Star suspension kits. If it is going to be for an all out professional race car team that has the manpower to fully clean & service the car after each event, I use the Wide Precision Chromoly rod ends with no liner for zero stiction. For regular racers ... and ProTouring cars ... I use the Wide Nylafiber Liner Chromoly rod ends. They self clean & lubricate, last the longest and only add about 1# of stiction.

Special Note:
The Watt's link Bellcrank & links in the previous photos were just for mock up. This Track-Star Watt's link uses the right rear lower shock mount for the lower right Watt's link mount to reduce weight out at the end of the housing (which affects grip). The lower right Watt's link will have a S-bend step in it. The Watt's link Bellcrank will be 7.5" instead of the 5" version in the mock up photos & use 1/2" rod ends, not 3/4". It will be black anodized, as will the sway bar arms.

The Watt's link rod ends used are:
1/2" x 1/2" Wide Nylafiber Liner Chromoly: 16,238# (Cost $16)

[carbuff]

Originally Posted by Ron Sutton

Here are the radial load ratings & costs for comparison:
3/4" x 3/4" Economy Mild Steel: 18,810# (Cost $12)
3/4" x 3/4" Economy Chromoly: 25,000# (Cost $17)
3/4" x 3/4" Wide Precision Chromoly: 28,081# (Cost $33)
3/4" x 3/4" Wide Nylafiber Liner Chromoly: 28,081# (Cost $26)

3/4" x 5/8" Economy Mild Steel: 19,350# (Cost $12)
3/4" x 5/8" Economy Chromoly: 27,000# (Cost $17)
3/4" x 5/8" Wide Precision Chromoly: 40,572# (Cost $33)
3/4" x 5/8" Wide Nylafiber Liner Chromoly: 40,572# (Cost $26)

Ron,

Can you explain why the larger ends have a smaller load rating? And are the costs between the 2 sizes actually the same? Interesting...

I replaced all of the ones in the rear of my car last summer with a set of QA1 ends. I cannot remember the exact 'family' of parts I used at the moment, but I did get the ones with the liners. XM series perhaps?

[Ron Sutton]

Originally Posted by carbuff

Ron,

Can you explain why the larger ends have a smaller load rating? And are the costs between the 2 sizes actually the same? Interesting...

I replaced all of the ones in the rear of my car last summer with a set of QA1 ends. I cannot remember the exact 'family' of parts I used at the moment, but I did get the ones with the liners. XM series perhaps?

The 3/4" × 5/8" rod ends have the same shank & body size as the 3/4" × 3/4" rod ends. Just the bolt hole & ball are smaller. So the 3/4" × 5/8" body has more material ... making it stronger.

[Solid LT1]

Hello, I'm wondering are the bottom coil over shock mount also being used for Watts Linkage mount on passenger side? Is all this loading on the bolt being mounted in single shear?

[Ron Sutton]

Originally Posted by XTRMEASURES

Great thread and great looking 3-link design. I'm glad i stumbled on it, ive being trying to deside on a rear suspension for my truck for about a year and a half. And i think this would give me both street/autocross performance without cutting or welding on the truck. Very inspirational and thanks for posting.

Oh and PS Mr. Ron Sutton for President!!!!!

Just an FYI ...
My Track-Star line of suspensions are far from "bolt-in". They require professional level fabrication & welding. Just saying this so there is no confusion.

For my clients that want to bolt in a higher level of technology & performance, I typically go one of two routes:
1. We work out their existing geometry, then I work up a harmonious suspension package of individual components from companies I like their stuff like Ridetech, Speedtech, Maier, JRi, etc. Together, we improve their suspension & steering geometry ... and put a more modern suspension package under the car. Almost always I've mapped out the correct sway bar & spring rates for a neutral, balanced handling vehicle. Plus we make the car run flatter (less roll angle) & run some level of higher grip shock valving.

2. Now with the Speedtech line of chassis & front subframes coming out, with optimized geometry from me, I simply work up the correct sway bar & spring rates for a neutral, balanced handling vehicle, make the car run flatter (less roll angle) & run some level of higher grip shock valving.

Those two routes above are how I work with my clients doing bolt-in projects. But I have quite a few projects in the works (most without build threads) with DIY clients or shops installing my custom Track-Star front subframes with long-arm, zero-scrub, high travel suspensions ... and/or four different versions of my Track-Star offset 3-links ... like Ron Myer's in this thread.

[Ron Sutton]

Originally Posted by Solid LT1

Hello, I'm wondering are the bottom coil over shock mount also being used for Watts Linkage mount on passenger side? Is all this loading on the bolt being mounted in single shear?

I copied this from a previous post on this thread to answer your question.

11. Weight is our enemy, so I design all of my stuff to be as light as it can be & still as strong as it needs to be. Plus I work to multi-purpose things as much as possible … to reduce duplication of items & unnecessary weight.

12. For example the upper Watt’s link crossmember serves as the shock crossmember also. Why run two crossmembers only a few inches apart? That is unnecessary weight. Of course it took me some work to make the packaging all fit well. But there are no wasted tubes, no duplication of mounts or crossmembers & no unnecessary weight.

13. Another example is the Watt’s link housing mounts. I see a lot of heavy, bulky mounts that clamp on. Just adding weight to the rear end. Most have to add two mounts to the housing. My design here dual purposes the right rear shock mount. This not only saves the weight of the bracket & bracing, but bolt hardware too. All of this weight is “unsprung weight”. The lighter we can make the rear end housing … especially out at the ends … the quicker the suspension can respond to irregularities on the track. Lighter unsprung weight in the suspension = more grip.

14. A common question is about the additional load that shock bolt sees with the lower right Watt’s link attached to it. Anyone that knows me very well, knows how safety conscious I am, so you know I did the math. I have a bolt load stress calculation spread sheet I use.

For those that care … calc’s ran as:
* 4000 # Car
* 50% rear weight (2000#)
* 1.5 G load
* 3000# force

No, Ron’s car won’t be that heavy … LOL. I like to do my calcs with more load on stuff than it will actually see. Like a safety factor inside the safety factor.

The bellcrank bolt sees half of the total force going through the Watt’s link.
* 1500# force on ¾” Grade 8 bellcrank bolt @ 1.156” = .0017” deflection (17/10,000)

The four bolts & rod ends each all split the other half of the load four ways, for 375# of force.
For weight savings, I utilize lightweight, tubular chromoly bolts on most mounts that are in double shear. For single shear suspension items, I use special 170,000 PSI 12-point bolts.

The combo shock & Watt’s link bolt sees loads from both the coil over shock & the Watt’s link.
* 1600# force on ½” 160k PSI link bolt @ 0.3125” = .0002” deflection (2/10,000)
* 375# force on ½” 160k PSI link bolt @ 1.1875” = .0022” deflection (22/10,000)
* The forces are from different vectors so the deflection doesn’t really total .0024” … but it doesn’t matter anyway, as anything this small is negligible.

P.S. Shear strength ratings of the hardware is:
* ¾” Grade 8 bellcrank bolt = 39,762#
* ½” 170,000 PSI 12-point bolts = 20,023#
* Chromoly Rod Ends 5/8” shank & ½” hole = 31,390#

----------------------------------

Remember, the coil-over shock applies a max load of 1600# & the Watt's link applies a max load of 375#.

[Track Junky]

[XTRMEASURES]

Yes more pics would be nice.... Thank you