sc10 rs shock shim removal help

[Thargor]

Hey ive searched the site so im sorry if this is a frequently asked and ive missed it.. and if it is please send the link...
i have a sc10 rs and im about to rebuild the shocks for the first time
a kid who is crazy fast at the track told me to remove the shock shims as it gives you more travel and a better performing shock..... has anyone done this? know if its a good tuning tip? or is he talking blls???
Thanks

[RC_Tomato]

Hey thargor.

Yeah this is a great topic you bring up. Ive also pondered this some time ago, read the forums everywhere but then decided to just mess around with downtravel limiters and see what happened to my sc10....so heres what i found....DISCLAIMER - these are just my findings...im sure others have found different!!

The answer to ur question is that it depends 100% on the track....as usual right! Ha! On a higher grip surface or on a track with less jumps, the car does better with shock downtravel limiters, which i think are the shims youre talking about.

On a high grip surface you are always fighting traction rolling, which occurs when the chassis leans and/or too much weight is shifted to the outside wheel. So downtravel limiters help here massively.

When the car turns it wants to lean to the outside, so the inside shocks extend themselves. If this is limited wth shims, it will prevent the rolling of the chassis to the outside. I tend to think of the shock limiters as being somewhat related to camber gain or what people call "roll center", though i find that term confusing. So if the roll of the chassis is limited with shims, then something else has gotta give....and heres where it depends completely on the track surface, tires, and many other components....

I race on a loose dirt track and i found shock limiters made the rear looser, but actually kinda helped me in the front shocks. Its definitely a per-track-basis, no hard and fast rules on it. It makes sense though that the rear limiters were so bad in my sc10. During the turn, the rear of the truck has to either lean or its gonna slide. If the inside wheel cant extend and maintain contact with the track, then extra pressure goes to the outside tire...and since the surface is low-grip, there simply isnt enough contact area/grip to handle it, so the car slides...boy is that ugly!

And further, if the inside wheel cant extend and keep track contact, then it might lift off the track surface, which would lead to the diff transferring power to the inside wheel since its now at lower resistance. And this is exactly what i saw on my sc10 with extra rear shock limiters: it was waaay loose exiting the turns and occasionally i could see the inside wheel spinning and then all hell would break loose.

I might be wrong but im now convinced this is partly why rc's typically have such long rear shocks relative to the front...that is, the rolling in the rear helps on loose surfaces.

On the front the rolling isnt nearly as important, i think beacause you can imagine that during the exit of the turn (as weight shifts backwards) its really just the outside front tire doing the steering and the inside is just kinda along for the ride.

[J_Bone]

As Tomato said, it track related. Less limiters will give you better shocks, but will increase weight transfer. This affects both side to side and front to back weight transfer.

[Thargor]

awesome this is good info .... the track i run on is big dusty and rough as hell..so im going to try removing all the shock shims and seeing what happens..
i changed the oil in the front shocks before racing tonight and removed the shims but didnt get time to do the rearsso i was probably running with the wrong shims out if u were going to take any out ... mad a few other little changes too... got my fastest lap ever qualified 3rd in the main and blew it with nerves and shoddy driving.... bah..
another race on sunday.. play around with settings and let u guys know how it goes.. im gonna practice a bit on saturday too... hopefully...

[RC_Tomato]

Taking out all the shims is a good experiment...give it a shot.

When i did that, i found the car was awesome on all the little bumps-and-ruts. It could soak up any like bumps with all the up and down shock travel. However, the car would lean all over the place (excessive weight transfer especially during accel/decel as mentioned by JBone above). All that weight transfer made the car literally catastrophic when enterring the turns....all the weight would shift forward and it was nearly impossible to keep the car's rear end from spinning around.

I agree with you though to give it a try and then start adding limiters until you find what you like. Props to you Thargor for wanting to try all this stuff out....i am the same way....most people just wanna know what to do and theyre not willing to experiment. I figure that the whole reason somebody buys a car like the SC10 is for all the adjustability! Otherwise could just buy an e-revo and go really fast!! Haha...

[RC_Tomato]

Hey thargor, i was just combing through my old bookmarks and found this awesome site that discusses suspension theory stuff. Check out the section on downtravel settings....it is really well written and in my experience it is bang-on...

R/C car handling: suspension components