Potential Issue With New Springs and Front Shocks on a Stock 2011 4Runner

[DougR]

Arrow in this image points to contact between the cut end of the lowest coil and the coil above it. I think this is a highly concentrated point of stress and there is a risk of it becoming a fatigue crack initiation site. What are your thoughts about it?

 

[HoosierJeeper]

Where's the lower spring isolator? I think that would prevent contact, since it would move that first full coil up and away from the end.

 

[DougR]

Where's the lower spring isolator? I think that would prevent contact, since it would move that first full coil up and away from the end.

These springs do not include an isolator, nor is one recommended by the manufacturer.

 

[AutoMechanic]

Seen them crack a lot. Are you thinking of replacing them? Or just putting something there to relieve the stress?

 

[Bottom_Feeder]

I would trust that Bilstein did their homework and wouldn't worry about it a bit.

 

[DougR]

Seen them crack a lot. Are you thinking of replacing them? Or just putting something there to relieve the stress?

At this moment, I want opinions from those with extensive suspension repair experience. I also want to hear from anyone with spring and/or suspension design experience. A Google search turned up one published technical paper analyzing fatigue failure due to contact between coils. See https://www.sciencedirect.com/science/article/pii/S2213290214000182

 

[DougR]

I would trust that Bilstein did their homework and wouldn't worry about it a bit.

I found a forum post where Bilstein denied a warranty claim because their 5100 shock was paired with a non-OEM spring. The lower coils of 4Runner OEM springs have wider pitch so as to not make contact.

 

[Greasymechtech]

What shocks springs liftkit or components?

 

[Bottom_Feeder]

I found a forum post where Bilstein denied a warranty claim because their 5100 shock was paired with a non-OEM spring. The lower coils of 4Runner OEM springs have wider pitch so as to not make contact.

That's not a Bilstein shock/spring combo?

Springs are cheap. I wouldn't give it another thought unless I had a reason to.

 

[DougR]

What shocks springs liftkit or components?

Dobinson C59-238 spring and Bilstein 5100 shock

 

[DougR]

That's not a Bilstein shock/spring combo?

Dobinson C59-238 spring and Bilstein 5100 shock. Bilstein product description simply states, "... designed to work with OEM springs ..." My OEM springs had sagged 0.75 inches, so I elected to buy new springs.

 

[Greasymechtech]

https://www.dobinsonsprings.com/index.php/suspension/springs/coil-springs

I wouldn't worry about it

 

[AutoMechanic]

At this moment, I want opinions from those with extensive suspension repair experience. I also want to hear from anyone with spring and/or suspension design experience. A Google search turned up one published technical paper analyzing a Mercedes spring fatigue failure due to contact between coils. See https://www.sciencedirect.com/science/article/pii/S2213290214000182

I have done loads of suspension work. I have rebuilt many Toyota suspensions before. I’m sure probably not as much as some others here though. They do crack a lot especially from the ones that were from up north I’ve pulled them off before and they have just been brittle. That is a cool study done by Mercedes and I’m glad they acknowledged it.