Axial SCX10 - Tuning Pt3: CMS Bump Steer Fixed.

[@Codesempire]

Great bit of info to help out anyone dealing with this. You are really getting that rig set up sweet. Great video too my friend. Thumbs up bro!

[@CarminesRCTipsandTricks]

*BAM!!!* 👏👏👏👏👏👏👍 EXACTLY what I had mentioned in an earlier Video! THAT'S set up properly!! Carmine 💥 ⛽

[@troyt3552]

Hey 4WheelRCUK, Thank you....Thank you...Thank you!!!! I have been trying to figure out my bump steer issue for a few months and I was about to bounce my head off the wall until your awesome Video Update! I had my buddies/ RC enthusiasts and even my local hobby shop and they couldn't even figure it out. I have the same pan hard L3 setup and watched a few how to vids along with both of yours and after 15 minutes problem solve!!! Again Thank you!!!!!

[@rcsworldofrcs]

Great vid bud! I like the idea of a Panhard kit and chassis mounted servo kit I need to learn more about them both,I think that might be the way I would like to set up me next build,it's a Tough Truck.. I'm getting a dingo kit and going from there!

[@chillichallenge449]

Thanks for your info, nice truck by the way.

[@JD-if9qw]

I am sooo late to this but damn did it help! Thanks for the vid.

[@4WheelRCUK]

Glad it helped. Old video but physics doesn't change :-)

[@TheTsunamilongboards]

I installed a similar servo mount with pan hard but I have lost some steering angle... what should I do to help get some of that lost steering angle back?!

[@ronaldayers9449]

Also, if you are running a panhard bar it is keen that you do not have a 3 or 4 link suspension on that axle due to the fact that the upper links in a 3 or 4 link suspension will "fight" the panhard bar on the side that it meets the axle when that sides suspension is fully compressed. The panhard bar is only meant and/or needed for a leaf spring setup to prevent any side to side travel of the axle, whereas if you have a 3 or 4 link setup the upper links already do that for you. As for the bump steer.. if you flip the servo over on that same mount to where the horn is located facing the rear of the chassis and have a drag link long enough you will overcome every bit of that "bump steer" we all see. What I mean is if your looking down at the chassis the less parallel the drag link is to the axle the better, weather its forward or backwards, doesn't matter.

[@4WheelRCUK]

Hello Ronald. Thanks for your comments but I have to say from experience that 1) 4-link upper links do not interfere with the panhard; my set-up is working great now and 2) You do need panhard with 3 or 4 link (if you have a chassis mounted servo). Without the panhard bar on my Rubicon the CMS waggles the chassis from side to side when it should be turning the wheels. YMMV of course - All SCX10 are different :-)

[@ronaldayers9449]

That's a fact! =) Thanks for all the time you put in and work you do. I did forget to mention that I have aluminum upper links so there is no need for me to have a panhard cause the metal uppers fix the axle side stress problem for me. I along with many others here in North Carolina enjoy and appreciate everything you do! Cheers!

[@ed0c]

i am still having bump steer issues, i have scx10.3 with panhard/steering arm parallel.

[@chillichallenge449]

Hello, i have the same panhard as you, and the same truck, i am just wondering what is the length of your new steer link from eye to eye?

[@4WheelRCUK]

+Brutus Demealius Hi Brutus. I'm guessing when you say "steer link" you mean the 'drag link' that goes from the servo horn down to the steering knuckles? I could give you some measurements, but what is a good length is very specific to your set-up (a couple of mm can make a huge difference) and affected by the length of your servo horn (and what hole on it you are fixing to), the type of rod ends you are using (they vary in length between say Axial and Traxxas), type of steering knuckles (stock plastic, alloy or alloy high clearance) and even how you are fixing the drag link to the knuckles (spacers to raise it up, if you put the steering link on the underside of the knuckles or above etc.). Best to get a bunch of spacers (1, 2, 4, 6mm etc.) and Axial threaded rods, so you can experiment. Or (might be cheaper!) just a long length of threaded rod and cut it to length. Then maybe cut another slightly longer or shorter as you dial it in to a good length. Essentially you want your servo horn dead center, wheels straight ahead and rig loaded/suspension compressed ready to run... Then make your drag link whatever length connects the servo horn to the knuckles, while keeping wheels straigh ahead. I changed my servo horn for a slightly longer one to get more steering turn and had to shorten my drag link a bit. Then I changed to the Level3RC steering link (level3rc-store.com/axial-racing-scx10-ax90044-4wd-rc-dead-bolt-c-34/scx10-steering-link-p-57), which gives you options where the drag link connects part way along the steering link instead at the knuckle and had to make an even shorter drag link! Good luck experimenting - It is a pain, but worth the time to get it right. Remember that a couple of mm makes all the difference :-) Word of warning: Don't do what you can see in this video as the screw that the drag link connects to is pointing up and I found that sometimes the tire would fold over onto the end of the screw and it was scraping rubber of the tire sidewall! Run your steering link screws pointing down, so you get the smooth hex head near the tire.

[@chillichallenge449]

Hello again thank you for your reply, yes i did mean the drag link. Ha. My truck is still stock when it comes to my servo horn and shocks, i have a 50mm (without rod ends) drag link to use and i will be using an angled rod end to connect to servo, i think it will give me about 80mm eye to eye linkage, would this be sufficient? Thanks again for you reply.

[@4WheelRCUK]

+Brutus Demealius "80mm eye to eye linkage" sounds in the right ball park, but as just a few mm makes a heap of difference, I cannot say for sure. Sorry Brutus.

[@emilykun7835]

well, how much longer link do we need to fix this? Thank you very much!

[@4WheelRCUK]

Hi Emily. Sorry but I cannot give you an exact length for the drag link, as this will be specific to your model (affected by the CMS kit you use, length of your servo horn, type of steering knuckles you have etc.). The key thing is to make sure that the drag link runs parallel with the pan hard bar. Then (with no drag link connected) center your servo and wheels and then you should be able to measure how far it is from the servo horn to the knuckle and go from there. Axial etc. make a bunch of spacers so you should be able to tweak the length of your drag link - a few mm really makes a difference.