Technical Question for the Suspension Gurus - Toyota Yaris Forums

KwonSau · 06-19-2007, 05:26 PM

Hi guys. I know it's generally accepted that installing aftermarket springs decreases the life of the factory shocks and struts...

My question is what, mechanically, causes the extra wear and stress? And is the decrease in strut/shock life proportional to the drop?

Thanks in advance for your advice. I used the search feature for this topic for about an hour (to no avail)

joey1320 · 06-19-2007, 05:46 PM

yes the decrease in strut life is proportional to the height which the springs lowers. the most it lowers the quicker it damages your struts.

read this info http://auto.howstuffworks.com/car-suspension2.htm and then imagine how a shorter springs makes the piston sit lower in the chamber and forces more oil out of the reserve cylinder over time.

thats why springs that drop the car a small amount feel normal/stock because the piston has enough space/height to move up/down. but if you drop the car 3" the car rides like shit and you will blow out your struts because the piston is pushed all the way down and can't absorb the bumps.

woof · 06-19-2007, 09:50 PM

True or not?

I asked a dealer about this and he claims the TRD springs (which drop the least) would have an effect but not a significant shortening of strut life.

Now, he didn't care to explain anything in terms of time frames. I guess the point is, if you get a 2" drop or more you might as well replace the associated gear as well.

I think, in the TRD case, one might trade his vehicle before those struts start spewing black gold all over creation.

brickhardmeat · 06-19-2007, 09:57 PM

did he suggest that you purchase the sport struts with the trd sport springs?

Shroomster · 06-20-2007, 12:29 AM

the only ways life of components is shortened/decreased is by either improper handling/usage or by swapping parts that have different tolerances/specs.

it was alreay said that changing spring height will decrease life span...it isn't a given number of miles or months as nobody drives the same way or the same roads.

if you swap early in the life of a part (i.e. change the springs out early on the stock suspension) you'll get eh maximum amount of life attainable with that setup(aftermarket springs with stock shocks) as opposed to changing springs out @ 50,000 miles on stock shocks...

follow me?

dallas · 06-21-2007, 11:31 PM

There are only two ways: lowering reduces travel, if the springs are not firm enough and bottom out it will accelerate wear, and also when a firmer spring compresses it kicks back harder and the strut must control this rebound leading to accelerated wear. It's such a small increase in wear I would not worry about it. Id be more concerned with making sure the spring rate is not to firm for the strut to control the rebound, you don't want the pogo stick effect.

06-19-2007, 05:26 PM	#1
KwonSau View User's Garage Drives: 2007 LB Meteorite Metallic Join Date: Jun 2007 Location: Bay City/Saginaw, MI Posts: 26	Technical Question for the Suspension Gurus Hi guys. I know it's generally accepted that installing aftermarket springs decreases the life of the factory shocks and struts... My question is what, mechanically, causes the extra wear and stress? And is the decrease in strut/shock life proportional to the drop? Thanks in advance for your advice. I used the search feature for this topic for about an hour (to no avail)

06-19-2007, 09:57 PM	#4
brickhardmeat Lonesome Cowboy View User's Garage Drives: 2007 WHITE HATCHBACK Join Date: Feb 2007 Location: Inner City, Dallas Posts: 2,995	did he suggest that you purchase the sport struts with the trd sport springs? __________________ SPONSORED BY

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06-19-2007, 05:46 PM	#2
joey1320 View User's Garage Drives: Yaris LB Join Date: Mar 2007 Location: Lakewood, Ohio Posts: 538	yes the decrease in strut life is proportional to the height which the springs lowers. the most it lowers the quicker it damages your struts. read this info http://auto.howstuffworks.com/car-suspension2.htm and then imagine how a shorter springs makes the piston sit lower in the chamber and forces more oil out of the reserve cylinder over time. thats why springs that drop the car a small amount feel normal/stock because the piston has enough space/height to move up/down. but if you drop the car 3" the car rides like shit and you will blow out your struts because the piston is pushed all the way down and can't absorb the bumps.

06-19-2007, 09:50 PM	#3
woof Drives: Yaris 3dr Hatch/Black Join Date: Feb 2006 Location: Deep South Posts: 114	True or not? I asked a dealer about this and he claims the TRD springs (which drop the least) would have an effect but not a significant shortening of strut life. Now, he didn't care to explain anything in terms of time frames. I guess the point is, if you get a 2" drop or more you might as well replace the associated gear as well. I think, in the TRD case, one might trade his vehicle before those struts start spewing black gold all over creation.

06-20-2007, 12:29 AM	#5
Shroomster '07 to '12:2 wipers to 1? View User's Garage Drives: '12 5-door LE & '14 5-door LE Join Date: Apr 2007 Location: Orlando Posts: 1,999	the only ways life of components is shortened/decreased is by either improper handling/usage or by swapping parts that have different tolerances/specs. it was alreay said that changing spring height will decrease life span...it isn't a given number of miles or months as nobody drives the same way or the same roads. if you swap early in the life of a part (i.e. change the springs out early on the stock suspension) you'll get eh maximum amount of life attainable with that setup(aftermarket springs with stock shocks) as opposed to changing springs out @ 50,000 miles on stock shocks... follow me?

06-21-2007, 11:31 PM	#6
dallas Drives: Yaris Hatch /Landrover D2 Join Date: Jun 2007 Location: Canada Posts: 242	There are only two ways: lowering reduces travel, if the springs are not firm enough and bottom out it will accelerate wear, and also when a firmer spring compresses it kicks back harder and the strut must control this rebound leading to accelerated wear. It's such a small increase in wear I would not worry about it. Id be more concerned with making sure the spring rate is not to firm for the strut to control the rebound, you don't want the pogo stick effect.