Suspension Notice for S/SS by NHRA

[Frank Bialas]

Originally Posted by acme383

Frank, What did they bush your idler with? Aluminum bushing? What kind of difference did it make? (not to get too far off subject)>

Dan you have a pm

[69Cobra]

You forgot one NHRA. I already make the corrections all you have to do is copy and paste it.

SECTION 10: STOCK, BRAKES AND SUSPENSION: 3, SUSPENSION, Front (Page 5) (2/4/2013)

Must retain complete stock front-suspension system as produced by manufacturer for body used. Lift kits/travel limiters permitted. Sway bar optional. Aftermarket tie rods strut rods with heim joints spherical bearings permitted. Electric shocks prohibited. See General Regulations 3:4.

[Tom Nolan]

Almost 30,000 views, poll, major safety issues and NHRA tech dept still ignores the stake holders! WTF?

[Billy Nees]

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[Mark Yacavone]

Originally Posted by Tom Nolan

Almost 30,000 views, poll, major safety issues and NHRA tech dept still ignores the stake holders! WTF?

Tom, Have you submitted that picture to NHRA?

Seems to me,that's the way to approach this:

You have to tighten the bushing too much to keep the rod from moving in and out when braking, staging...Thereby stressing the OEM rod until it breaks, as shown.

[Bobby DiDomenico]

Originally Posted by Tom Nolan

Broken strut rod photo!

Do you think this happened because the stiffer bushing didn't compress like the factory rubber one and caused the shaft to flex there? We had a car where the rubber one had cracked and moved which then was allowing the retaining washer to hit upon braking but never had a rod go like that.

[69Cobra]

Originally Posted by Mark Yacavone

Tom, Have you submitted that picture to NHRA?

Seems to me,that's the way to approach this:

You have to tighten the bushing too much to keep the rod from moving in and out when braking, staging...Thereby stressing the OEM rod until it breaks, as shown.

I agree!!!! Please send that if you haven't already.

[69Cobra]

Originally Posted by Bobby DiDomenico

Do you think this happened because the stiffer bushing didn't compress like the factory rubber one and caused the shaft to flex there? We had a car where the rubber one had cracked and moved which then was allowing the retaining washer to hit upon braking but never had a rod go like that.

Yes! Exactly the polyurethane bushings do not flex at all and are probably the worse thing to use.

Originally Posted by Tom Nolan

Almost 30,000 views, poll, major safety issues and NHRA tech dept still ignores the stake holders! WTF?

Its appears they don't care how the stake holders feel.

[Bill Harris]

Polyurethane does flex a little, surely not as much as the OEM rubber, especially a 40 year old rubber bushing, but they have a little give. However, a spherical bearing like the Calvert for the FoMoCo cars absolutely positively does not flex at all. So please explain why it is inadvisable to use a poly bushing while arguing to use a solid bushing instead?

The OEM strut rods were not designed to take the beatings they see when a 3500 lb car comes down from a 3+ foot wheelstand. Nor were they designed to maintain perfect alignment when someone stands on the brakes at 120+ MPH.

As you can see in that picture, the Ford strut rods are necked down and threaded and the break is at the threads which are almost certainly cut and not rolled, making them weak (stress risers galore). Coming down from a wheelstand puts those rods in tension and if there is no compliance from the bushing the rods are going to be prone to breaking at the threads. The break in the picture has nothing to do with over-tightening the bushing as the portion of the rod that is being subjected to tightening tension is between the two nuts.

I have the Calvert spherical bearing on a SS/GT 69 Mustang and I am seriously considering taking them off and replacing them with new OEM rubber. I don't think a solid bushing should be used with an OEM strut rod, especially 40+ year old units. Rather, aftermarket or custom made strut rods should be used that has enough safety factor designed in to make sure it can stand up to this sort of abuse.

If this is about safety, then the last thing you want is a solid bushing.

[Mark Yacavone]

Originally Posted by Bill Harris

Polyurethane does flex a little, surely not as much as the OEM rubber, especially a 40 year old rubber bushing, but they have a little give. However, a spherical bearing like the Calvert for the FoMoCo cars absolutely positively does not flex at all. So please explain why it is inadvisable to use a poly bushing while arguing to use a solid bushing instead?

The OEM strut rods were not designed to take the beatings they see when a 3500 lb car comes down from a 3+ foot wheelstand. Nor were they designed to maintain perfect alignment when someone stands on the brakes at 120+ MPH.

As you can see in that picture, the Ford strut rods are necked down and threaded and the break is at the threads which are almost certainly cut and not rolled, making them weak (stress risers galore). Coming down from a wheelstand puts those rods in tension and if there is no compliance from the bushing the rods are going to be prone to breaking at the threads. The break in the picture has nothing to do with over-tightening the bushing as the portion of the rod that is being subjected to tightening tension is between the two nuts.

I have the Calvert spherical bearing on a SS/GT 69 Mustang and I am seriously considering taking them off and replacing them with new OEM rubber. I don't think a solid bushing should be used with an OEM strut rod, especially 40+ year old units. Rather, aftermarket or custom made strut rods should be used that has enough safety factor designed in to make sure it can stand up to this sort of abuse.

If this is about safety, then the last thing you want is a solid bushing.

Bill, I don't know where you're coming from on this. I don't have an engineering background and it sounds like maybe you do..
So, are you saying the break in the picture was caused by stretching, rather than flexing?

Thanks