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-   -   shock pre-loading (https://www.rctech.net/forum/nitro-off-road/244693-shock-pre-loading.html)

jrwoodchuck 09-28-2008 12:36 PM

shock rebound!!! oops,,
 
I mean rebound!!
After reading some threads, I saw people talking about when they do it and when not to, and I understand. But my question is. How do you build the shocks to get the amount of rebound that you want.

jamminnay 09-28-2008 12:47 PM

you can adjust it by how much oil u push out when bleeding... i typically run very little rebound..

maximuspowell 09-28-2008 12:47 PM

? huh

jrwoodchuck 09-28-2008 01:23 PM

So you push more oil out to get less rebound?

jamminnay 09-28-2008 01:35 PM

correct.. and leave more oil in for more rebound.. you need to be very precise making sure they are all the same.

boostfiend 09-28-2008 01:51 PM

If you download this....

http://www.teamxray.com/teamxray/sho...p?file_id=4455

and look at page 32, there is a step by step for alternate rebounds.

jbrow1 09-28-2008 02:01 PM


Originally Posted by jrwoodchuck (Post 4885051)
After reading some threads, I saw people talking about when they do it and when not to, and I understand. But my question is. How do you build the shocks to get the amount of preload that you want.

Preload would be adjusting your spring collars or clips to lower or raise the cars ride height. What you are talking about is the rebound of the shock.

jrwoodchuck 09-28-2008 07:21 PM


Originally Posted by jbrow1 (Post 4885206)
Preload would be adjusting your spring collars or clips to lower or raise the cars ride height. What you are talking about is the rebound of the shock.


Man you're right. Glad you knew what I ment and not what I wrote. I know how to adjust pre-load, it's rebound that I was courious about.

maximuspowell 09-28-2008 07:26 PM

so what's better 50% rebound or 100% rebound. Also what do you do if the rebound is noticeably different?

jrwoodchuck 09-28-2008 07:50 PM


Originally Posted by boostfiend (Post 4885188)
If you download this....

http://www.teamxray.com/teamxray/sho...p?file_id=4455

and look at page 32, there is a step by step for alternate rebounds.

thanks, that works!

PTP Racing 09-28-2008 07:55 PM

Its all about the amount of compression behind the bladder in a shock. As the shaft enters into the bore of the shock it displaces oil. Because of this building the shocks with the shaft in different amounts will yeild different amounts of rebound. I usually build mine with 100% rebound per the Xray manual (shaft all the way out) but have done some experimenting with less. In very rough conditions it may be better to have less rebound so the buggy can react to the bumps quicker without letting the rebound act as a stiffer spring. I feel a shock with more rebound has a more progressive feel and is less likely to bottom out over big jumps. My thinking is building with 100% rebound is easier for me to duplicate even rebound from one shock to the other and if I need better bump handling I will adjust my shock oil accordingly.

topcat-lll 09-29-2008 10:09 PM

Compression and rebound can only be adjusted in r/c shocks by changing
shock fluid. The rebound rate will always be the same as the compression
rate. In automotive type shocks there is a compression stroke check valve
that increases the compression stoke rate going up and relieves the rebound
stoke going down. Therefore increasing traction by keeping the wheels on the
ground. Maybe one day R/C cars will get this type of shock.

lowey79 09-30-2008 02:31 AM


Originally Posted by topcat-lll (Post 4890352)
Compression and rebound can only be adjusted in r/c shocks by changing
shock fluid. The rebound rate will always be the same as the compression
rate. In automotive type shocks there is a compression stroke check valve
that increases the compression stoke rate going up and relieves the rebound
stoke going down. Therefore increasing traction by keeping the wheels on the
ground. Maybe one day R/C cars will get this type of shock.

What you're saying is correct, but "rebound" when refering to rc shocks is how far the shock shaft extends after compressing it. This is due to the oil that the shaft displaces when compressed.

bjr48 09-30-2008 04:25 AM


Originally Posted by jrwoodchuck (Post 4886240)
thanks, that works!

+2 :nod:
I am always playing with taking a drop or two of fluid out of the shocks to play with rebound. Not that I knew how much rebound I might want but always knew all shocks should be equal. This method allows you to set how much you want by where you place the piston during filling. VERY nice.
Also saved me from buying new driveshafts. I didn't know the pins could be pressed out and replaced! And didn't know that the next step after your pins get flat was for the drive cups to start getting trashed. I already "recycled" the pins from a bent front axle to rebuild my center diff to front driveshaft good as new and will order some Hudy pins over the winter to fix the rest! Easy stuff.
I saved the manual as there are quite a few tips in there that Kyosho never gave me :weird:
Now if I just knew how much rebound I want. I'm guessing 100% from the later comments. Our track is relatively smooth and I bottom out bad so it should help some along with some other changes I plan to make for next year.


Does setting up for 100% rebound put tons of extra pressure inside the shock body and cause any side effects?:confused:

Akhor 09-30-2008 06:52 AM


Originally Posted by bjr48 (Post 4890854)
+2 :nod:
II didn't know the pins could be pressed out and replaced! And didn't know that the next step after your pins get flat was for the drive cups to start getting trashed.


Can you do this with any drive shaft or only the 808?


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