shock help plz?!?!

[rckid91]

i just took the shocks off my revo 2.5r the fluid was nasty grey why???

next question what wieght is good in a revo???

third question i started filling the shocks with some 40 wt i had and after filling it i noticed if i compressed the shock the fluid did not push the piston down is this right?? my tmaxx shocks push thepiston down and extend the shock even without springs

thanks in advance guys
bob

 

[itsalifeworthliving]

hey bob. its just excess rub from the plastic piston and the metal case,(not anodized) also picking up some fine dust from the shock shaft.. do they leak? your right, it should push down the shaft after its filled, evan with no spring.. its not a huge deal, but you sound anol, like myself.. thats good!! make sure that there is no air in the shock.. the rubber diaphram(?) in the shock cap should be bubbled out, not pushed in to the cap. fill it all the way to the top, when you put the cap on you should see a little oil coming out of the pin hole on top of the shock cap.. and thats it, it should be full..as far as shock wieghts, it depends on your drive style and conditions.. 40 wt is a good place to start, but you might want to try a couple others to see whats best for you..

 

[rckid91]

thanx man exactly the info i was looking for so maybe some shock rebuild kits added to the errand list tommorrow

they dont leak there just isnt any back push on the piston maybe i have a bad piston?

 

[CHRIZDIZLE]

If I remember correctly the shocks should not push them selfs back out. That is what the spring is for.

 

[itsalifeworthliving]

ya your right chriz..i forgot that part being the spring and all.. what doeas the rubber stuff around the rim do?uke:.... bob, i would'nt worry too much bout the back pressure.. the pistons should last forever unless they crack, the back presure is coused by a slight amount of foaming in the silocone.

 

[rckid91]

hmmm ok i guess ill just put them back on once i fill them but what wieght do you guys suggest for tracklike conditions

 

[beason]

the shock should rebound a little, but not all the way back out. the reason is when you push the shaft in your adding volume to the cylinder, ( the shaft) which compresses the fluid a little. as far as fluid weights it depends on your setup, springs, rockers, track, and driving style. do a search for revo setups on here and you should be able to find a good starting point.

 

[SublimeRevo]

the shock should rebound a little, but not all the way back out. the reason is when you push the shaft in your adding volume to the cylinder, ( the shaft) which compresses the fluid a little. as far as fluid weights it depends on your setup, springs, rockers, track, and driving style. do a search for revo setups on here and you should be able to find a good starting point.

Actually fluid or liquids are not compressible. You are increasing the pressure inside of the shock which causes the shock to rebound.

 

[beason]

ok so i stand corrected, you compress what little air is left in the cyclinder.. lol...

either way they should rebound just a little, maybe half way.

 

[rckid91]

mine dont rebound at all with brand new 40 wieght oil in them filled all the way up

also is 40 wt a good starting point for a revo with stock everything long travel rockers and a hard pack small jumped track

 

[SublimeRevo]

The pistons in the shock have holes in them that allow the fluid to transfer from one side of the piston to the other in a controlled manner giving you damping. The spring is what extends or rebounds the shock. A shock without a piggyback resivor that is charged with a gas of some sort (air/nitrogen) will not extend on its own. The pressure of the fluid is equal on both sides of the piston causing no movement without an outside force acting on it.(spring or a gas under pressure)

 

[rckid91]

true makes sense

 

[SublimeRevo]

I know we are talking about rc's here but I have taken an advanced suspension course with one of the manufactures of motorcycle racing suspensions. Helps to understand alot better.

 

[HILLFINGER]

mine dont rebound at all with brand new 40 wieght oil in them filled all the way up

also is 40 wt a good starting point for a revo with stock everything long travel rockers and a hard pack small jumped track

40wt is fine most people run between 40wt & 50wt.

 

[rckid91]

well the guy at the local track said 35 or 40 so i went ahead and did 35 but i think its a wee bit soft

 

[itsalifeworthliving]

it depends on the 35 wt.. yo have three diffrent adjusting point, your shock piston, silocone wt, and spring rate/tension.. you might just wana pick up springs and juice and have a day at the track.. I'm running stock piston,40wt rear, 45wt front, with white and silver springs..

 

[rckid91]

I'm running traxxas #3 pistons in the front with the #1 in the rear 35 wt. oil all around and i have blue and silver springs