If the tires are bouncing then it sounds like the rear is dampened too much or has too much pack. You could either try larger/more holes in the pistons or going down in shock oil in the rear. Keep in mind you will probably have a tradeoff somewhere else on the track so use whichever one is fastest time wise.

T4.1 FT

I still say it bounces around, said that from the beginning. You're stuck on springs, it's not the springs. I'm running green rears. When I spring balanced the car I found balance with different spring combinations. To move to a softer rear spring which would be the Black, it would force me to change the front to Silver. I was slapping on every jump landing with this combo and the truck felt sloppy around the track. My current spring set up is correct for my track, just trust me on this one.

My problem is somewhere inside the shock, be it piston, oil, or a combination of the two.

edit: didn't see this post
Thank you Fred!! That's exactly what I was thinking and where my train of thought was. Good to know I'm picking up what you're putting down!!

Appreciate all you've done in this thread good sir.

That's true. It's a volume/velocity issue. If we had 2 shock with the same total piston hole area with the same stroke but one was a big bore and the other wasn't, the big bore would have more pack since it's trying to move more fluid through the same sized holes in the same amount of time.

Actually there's an interesting idea. With a 2WD buggy with more than 2/3 of it's weight on the rear, why not run a big bore in the back only and not the front? I may have to ponder that one for a while.

Hinecken,
The compromise I found that works with my T4.1 is dual stage pistons. They don't make me any faster, but allow me to maintain my speed when the track gets rougher.

Fred or any losi scte guy. I'm trying to get a softer spring balance on my sons scte. I had blue front top in bottom in and green rear all out( hardest spring offered) . But this is the softest balanced set up with springs I had available..
well I noticed in the front that I can get the blue springs softer by going top laid in and bottom moved out which gives more angle . With the extreme difference in between front and rear shock angles would I not have to run a lot thicker oil. ?
I was able to find a setup wit
Front blue bottom out/ top in
Rear orange bottom out / top out
Now my truck is 8-9oz lighter and found it hard to get it soft enough also
Front green mid top/bottom in
Rear silver out top/bottom in
O also by laying shocks in limits travel how does this effect truck tks

Eventually I'd like to try a set of those out. I replaced the #2 pistons with #1's that have larger holes and stuck with the 27.5wt oil. Truck felt better around the track but was still misbehaving a bit down the straight and coming off of jumps. I couldn't figure it out. Then I took a good tumble after a rythem section and broke a solder joint. While inspecting the motor, I discovered the bent axle that was there the whole time!

New CVA bones on the way and problem should be cured.

Ok so I've got the springs balanced, I've got my oils relatively dialed in, and I've used the camber links to get the rear traction closer to where I want it. All that is going well and good. RB5 is handling better than it ever has and I'm thankful I learned all of this so I know what I'm doing with "tuning" now. Before I started all this, I truly had no real idea what I was doing. Now I feel like I have a pretty good idea.

I'm still having a couple issues though. First I'm getting a lot of bouncing. I'm having a hard time figuring out if it's bouncing on the springs or if the wheels are bouncing. It's not so easy to tell just by looking at the buggy as it goes around the track. I also noticed that it seems to have a lot of rear end slap. Granted this is usually when I land rear biased, but just an observation I had.

I'm also having a bit of a rough time with rear traction in certain areas of the track. One of the areas is after a rhythm section. I'm landing off a smaller double, good speed, and into a 90 turn. I keep spinning out coming into this turn for some reason. I've changed my roll center in the rear by raising the inner link, and by running the camber link fairly long. I'm thinking this has something to do with the suspension issues as well.

I'm thinking it's either that I need to go with a softer spring rate overall (or just in the rear), or experiment more with shock oil. Right now I'm running 35f, 30r.

Here's my plan, hopefully it will help. I'm going to go up to 35, 40, 45 weight in the rear. I just want to find that point where I KNOW it's too much damping, and then work my way down from there.

If I still can't get it to handle the way I want, I'll try to change the rear springs. I saw earlier in the thread that a person ended up liking a bit stiffer front that the rear. I might need to do this as well to get the rear traction I want.

Have someone video tape your car specifically relatively close up through the sections you are struggling with. Then watch the video slowed down significantly to see what the chassis/suspension are actually doing. This is usually beneficial for me. I'm a visual learner.

I can't think of any reason why this would be a bad idea.

Hi fred,

question for you...
CONTEXT:
On a bumpy track with a 4wd, with anti-roll bars fixed, that the left had side is fighting the right hand side due to the different sides riding different bumps.

QUESTIONS:
What should i be looking for, to know that i shouldn't be using anti-roll bars?
What should i be looking for, to know that i should be running more droop?

Also:
Im running a 8ight EU, with all the servos up the front (GEN III radio try).
Im not getting the amount of off trottle steering i would like, middle corner is a little inconstant, and on power the car goes loss on me and i have to be very gental.

Is this a weight issue...im thinking that adding a few grams in the back i would get more weight transfered to the front during braking , and would counteract the weight of the two servos up-front. this should also make the mid corner more constant...what do you think?

cheers,
David

Hi All,
Have really enjoyed reading all the great info in this thread. There seems to be quite a few very smart people following this thread, so I was hoping someone can answer this question for me. I am using a 5 x 1.3 piston with 37.5wt oil and am happy with the performance but would like to try a 4 hole piston with a lighter weight oil. Is there some formula that can be used to figure out what size hole and wieght oil can be used to achieve a good starting point to have approximately the same performance (i.e. pack)?

I would try going up 5-10w in oil. Try 5, then 7.5, then 10 and see what you like the most. I don't think there is any formula for this, just trial and error. But I think 5 or 10 would be a good bet.

I don't think you can get the same pack even if you find a lighter oil that feels the same with 4 holes. The whole point of having less holes and lighter oil is to increase pack.
You can find a combo that will have the same feel on the bench though. If you keep the same hole size, 1.3mm and go from 5 to 4 holes, that equals 4/5 or 0.8. You can get about the same feel with 37.5w x .8 = 30w, but that setup will have more pack.

Hmmm. Kinda simplified, but it might get you in the ballpark. If the method works, then that's the important part.

Can this thread be made a sticky please, some of the best RC reading ever in here.