Hi All,

I've been absorbing all the information this forum has to offer for a few years now and finally decided to register today as I have a question I was not able to find an answer for in searching here.

I have a 2005 GX470 with about 140K miles. I just replaced the rear shocks, which were completely shot, and figured that the fronts were probably ready to be replaced as well. The question I have is whether I should swap out the springs along with the shocks or if the original springs should still be good.

I do not use this for any 4x4 adventures as it is a daily driver and used mostly on paved roads.

Thanks for any info you can provide.

Bart

 

It's getting to the age/mileage that the springs are probably not performing the same as when new, but if you're putting stock spec shocks on, then you might as well just keep what you've got.

Stock spec shocks won't be calibrated to deal with aftermarket spring rates, and it will ride poorly. This limits your options to new stock springs. New stock springs isn't something I'd pay for unless I had a broken spring I needed to replace. Used 120 series 4Runner or FJC springs is another option, I'm not sure the GX470 front spring specs, but here's a chart showing some options for 120 series trucks, maybe one of those would be a nice 1/2" or 1" bump over stock?

https://s31.photobucket.com/user/bea...2lsyh.jpg.html

 

I put Bilstein 5100’s on the rear and will likely use the same on the front. Not sure if that changes anything regarding the springs....

 

I changed to Bilstein 5100’ s at 90,000 miles using the original springs. Had to lift the front about 1.25” due to spring length ... so adjusted the rear height switch (raised rear) to maintain stance. Huge improvement over the stock shocks.

 

Did you lift the front end on purpose, or did it get lifted due to the spring attachment points on the shock itself?

 

I believe 5100's have an adjustable lower spring perch that affects ride height for the front struts. I've heard you only want to use the lowest or middle settings, the highest setting causes a harsh ride.

 

The 5100's are longer than stock shocks. To have ANY level of OEM spring compression when assembled you CANNOT use the lowest (no lift) spring perch position with these shocks. Restated ... the stock spring is not long enough for the lowest spring perch (no lift) position ... so you must have some lift using the OEM springs with these shocks. I used the lowest possible spring perch position that JUST compressed the spring during assembly ... resulting in 1.25" front-end lift ... as installed by a Lexus dealership. With rear air bags, it's easy to adjust the neutral sensor position to lift the rear to maintain stance. I did go with taller tires when making this change ... the stock tire size look lost in the wheel well with any level of lift.

 

From what I've seen about spring rates either a 600 or 650 lbs/in spring would be what you're looking for in the front if you want to replace them. I think 600 is factory and 650 will help with the nose dive under braking but be slightly harsher

 

Spring Rate is all good and fine, but spring length is equally important. The 5100's are longer than stock shocks, so if one wants to maintain stock ride height, longer springs are necessary.

 

Thank you for all the replies. So if I want to keep the front at stock height (the 5100's in the rear didn't seem to lift the back), and I don't need to replace the stock springs, what would you suggest as good alternative to the 5100's?

 

The rears did not lift because ride height is determined by the (stock) spring (or air bags) that are not integral to the shocks ... so no lift happened. The fronts are an integral shock-spring assembly. You probably should have used Bilstein 4600's ...

 

So are the 4600's the same length as stock on the front and are they a good alternative? I haven't actually purchased the front shocks yet. Still trying to get an idea of the most appropriate aftermarket option for the front at this point.

 

The GX has a factory rake so if you raise the front 1-1.5" with 5100s you can get it to sit level. If you are just going for a factory replacement the 4600s would be a better choice as they are designed to replace the factory parts. That said you can make 5100s work in the front but it will lift the truck like ASE said. If you still have the air suspension in the rear you can adjust the height sensors and make the truck sit level front to back.

 

Thanks again gentlemen. It sounds like unless I want to mess around with the rear height sensor to level the ride with the newly heightened front, the 4600's are the best option. If anyone has other thoughts, I would love to hear them.

Thanks

 

I wouldn't be afraid to mess with the height sensors if you can replace the suspension yourself. Its pretty trivial and just involves undoing and adjusting a few nuts