ColeB

I have an Arrma Talion truggy and I am trying to tune the rear suspension and could use a little help. When I got the Talion and started running it, I noticed the rear suspension was not doing very well at absorbing bumps. When I tried dropping it on the floor, the front end would do a great job at absorbing the drop but the back does not compress. The rear a arms do not go past level (the ride height). I got thinner shock oil from 550 sct to 460 and it has made zero difference. I don't think it is the spring that is the issue and I already tried changing the oil, so maybe change the thing inside with the holes bees to be less restrictive? This is the first suspension I have tried to tune and I am not sure what to do next.

collector1231

My Feedback: (1)

Maybe one of the E clips on the shaft holding on the piston is gone and its just spring? Take apart the rear shocks and put them back together would be the best option because it sounds like somethings wrong.

RustyUs

Take apart the shocks completely, and roll the shaft on a flat surface...any little bend on the shaft...it's time for a new shaft. I don't think the nut coming off the shaft, inside the shock, would do much of anything other than give you no dampening whatsoever. If you find the shock shaft isn't bent, just clean everything real good and put some new oil in and seals (if the oil looked like mud).

When assembling the shafts, just make sure the threads/locking nut(s) for the pistion(s) are clean and dry.

EXT2Rob

My Feedback: (1)

Cole, do you read your post before you post it? You got what kind of shock oil?? I don't think 550 or 460 is a shock oil weight. (Or your using some gravity notation I'm not familiar with) And you've got one sentence that doesn't even make sense. Hard to help if we don't understand the question.

If you can't get the rear suspension to compress and get the rear arms beyond level, then something is binding. Preventing the arms from moving. Or you have a seriously screwed up shock. Take the shocks off the car. Can the suspension arms move freely through their full range of travel? If not, look for what's causing the bind. If they're fine, then look at the shocks. Compress each one. Do they feel the same? Do they compress smoothly? Take off the springs, compress them again. Do they even have any fluid in them? Are they leaking? Rebuild if necessary.

ColeB

Rob, I am using cst for the shock weights. It's a different term (like pounds and kilograms are different) which I assumed you heard of because you seem like you are pretty into the hobby. The shafts are not bent, they compress smoothly. When I drop the Truggy they compress about halfway and then don't really move much further because they are too stiff. When I push on the rear end they compress all the way, but rebound very slowly too. I changed the oil, which was clear, to something thinner. The suspension arms move smoothly so nothing is binding. When compressing the shocks with no spring they feel like they have extremely thick oil but they don't. The oil change didn't make a difference in performance. This is not an issue of mechanical failure but tuning! What should I try doing now? Im pretty inexperienced with RCs so my RC lingo is not very good. Hope all this makes sense.

ColeB

Collector, what are E clips? I don't really understand what the first sentence means.

RustyUs

Some companies use e-clips on both sides of the shock piston to keep them in place. If you never heard of e-clips before, be thankful. They have a tendency to fly in every direction.


I believe the Talion uses a locking nut to secure the shock piston on the shaft. Which is why I said about when rebuilding the shocks... to try to keep the nut's nylon locking piece and the shaft's threads clean and dry. This way the locking nut will stay put (not loosen).

zukiguy

If your shocks have too much oil inside they will be difficult to compress all the way. I am new as well and I noticed this issue on my old 1/18th buggy and my new 1/10 buggy. I removed a tiny bit at a time by dabbing a paper towel in the shock oil until they compressed all the way smoothly with the caps on.

Edit: Did a little Googling and I found out that there's a technique called bleeding that gets excess oil out much more easily
http://www.rcuniverse.com/forum/rc-1...led-shock.html

ColeB

Thanks for the advice. However, my shocks come with holes in the side of the cap that are used for bleeding. I twist the cap on one rotation, compress the piston and all the excess oil comes out, then screw the cap tight. I did that when I changed the oil so I can eliminate that from the possibilities of what is going wrong.

EXT2Rob

My Feedback: (1)

zukiguy said what I was gonna say. Hmmm.... Do your shocks have bladder caps? That's a dome-shaped rubber thing that fits inside the top shock cap. It is there for "volume compensation". I have a similar shock to yours. Usually, they can compensate for not being filled perfectly. And, if you do over fill, the bladder tends to push out the excess all over the shock before you even get the cap threaded on! But it is possible to over fill it if it wasn't bled carefully. That might be what your getting a little of. But in your followup post, it sounds like the car is more or less behaving normally. You just may want to get a softer set of springs for the rear if you feel the ass end is too bouncy. You might also try moving the top shock mount position to the outer-most mounting hole.

ColeB

Do you mean the most inside mounting position? Moving to the outside would make it less progressive, or firmer sooner. Mine doesn't have mounting holes for the bottom of the shock but moving to the outside would make it less firm if I did that. And it does have bladder caps. I guess I will try even thinner oil and see if it makes a difference. I don't think the spring is the problem because the ones on the front are just as firm but behave perfectly.

EXT2Rob

My Feedback: (1)

Yeah, but that doesn't mean that the rear springs could still be too stiff for your running ground if you think the rear end is too bouncy.
And you're right, I was wrong about that upper shock position. You'd want to move the lower mount to the innermost position, that will increase leverage on the arm, making the spring and damping rate seem softer.

You might want to have a look at this thread, and maybe message HoldDaMayo about his Talion. He races it at the local track and may have better insight into your issue. http://www.rcuniverse.com/forum/rc-e...ah-review.html

You can send him a Private Message (PM) . Click on his screen name and select Private Message. The reply comes in the Notifications link in the forum banner. You are notified when he replies.

ColeB

Thanks Rob. Also, thanks for your help over the past month along with the other regulars. It's been really useful in getting my first larger scale Rc up and going.

EXT2Rob

My Feedback: (1)

Thanks, man. Yeah, there are some pretty knowledgeable folks here. More experienced than me. I've learned a lot from them too. I really appreciate this place.

Oh, about PM'ing HolDaMayo, I'm not sure he responds to PMs (been a while, can't remember) so you might want to just post in that thread of his, he'll see that and may be able to help ya.