Rc4wd cms?

[Corey123]

Hey, just noticed rc4wd is offering a cms kit for scx10's! I like this idea because I can run a 4link on the front instead of HB's 3link... Just curious if anyone else has considered this option??

[TSK]

Hte main problem with runing a chassis mounted servo combined with a 4 link is the severe bump steer.

The axle will move straight up and down, whereas the steering link will travel on an arc.

In my experience, expect about 15* of steering deflection (bump steer) as the suspension compresses.

[Corey123]

hmmm.. would i still get the encounter that same problem with the factory "3 link" ?

[rngrchad]

Originally Posted by Corey123

hmmm.. would i still get the encounter that same problem with the factory "3 link" ?

very little if any with the factory 3 link....however expect the three link to pop out of the axle bracket when under heavy binds....

[TSK]

Originally Posted by Corey123

hmmm.. would i still get the encounter that same problem with the factory "3 link" ?

Yes.

Originally Posted by rngrchad

very little if any with the factory 3 link....however expect the three link to pop out of the axle bracket when under heavy binds....

This is both worng and correct.

Bump steer will still occur with the factory 3 link as the axle still move's straight up and down when the suspension is compressed while the steering link moves on an arc.

But you are right about the 3 link popping out.

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The factory 3 link is more like a 4 link with a unified mount location on the axle. The Hand Bros CMS 3 link differs in that it is a true 3 link setup with a panhard bar (which ironically means it has 4 links) The pan hard bar swings on an arc just like the steering link does. And since the panhard bar controls the lateral (side to side) movement of the axle, there is no bump steer as the axle movesto the passenger side as the suspension is compressed. by having the axle move to the passenger side, the bump steer is elimintaed.

Factory 3 link & 4 link:
- Axle moves straight up and down when fornt end is compressed.
- Chassis mounted servo's steering link swings on and arc. As front end is compressed, the front wheels/tires witll be forced to point to the passenger side (assuming servo is on diver's side of frame and steering link attachs to passenger side knuckle.

Hand Bros CMS 3 linnk:
- Axle sldies over to the passenger side when the front end is compressed. This is due to the panhard bar (which swings on the same arc as the chassis moounted ervo's steering link.)
- Tires stay point straight ahead when the front end is compressed because the chassis mounted servo's steering link swings on the same arc as the panhard bar.

[salmonfacesalad]

It's nice that rc4wd offers this to run their axles on the scx10 frame but it needs a track/pan hard bar to get full steering throw in each direction. otherwise the suspension cycles through the drag link and forces the knuckles to achieve half throw in one direction and full throw in the other during travel or articulation.

[TSK]

Originally Posted by salmonfacesalad

It's nice that rc4wd offers this to run their axles on the scx10 frame but it needs a track/pan hard bar to get full steering throw in each direction. otherwise the suspension cycles through the drag link and forces the knuckles to achieve half throw in one direction and full throw in the other during travel or articulation.

BUMP STEER!!!!... can make things fun in a 10lbs 2 speed brushless scaler at full throttle though.

[rckjeep]

Originally Posted by TheSCorpionKing

Yes.



This is both worng and correct.

Bump steer will still occur with the factory 3 link as the axle still move's straight up and down when the suspension is compressed while the steering link moves on an arc.

But you are right about the 3 link popping out.

I totally agree. Any configuration that locks the axle from left to right will have bumpsteer with a CMS kit. I've made a few homemade CMS kits which always include an axle truss with a panhard mount. Not only does it eliminate or reduce the bumpsteer, it looks way more scale in my opinion.

As far as the RC$WD kit, it's typical for them to not do R&D. Stick with the Hand Bros. kit they did their homework and the kit works awesome or just make it yourself.

[Corey123]

Thanks for the input guys! I've been reading and doing research on cms because I absolutely hate having a servo on the axle on a scaler, hahaha! I like the looks of the hb kit, just tryin to check out my options. So, I guess the hb kit is the way to go?

[salmonfacesalad]

Originally Posted by TheSCorpionKing

BUMP STEER!!!!... can make things fun in a 10lbs 2 speed brushless scaler at full throttle though.

oh yes i agree.

[TSK]

Originally Posted by Corey123

Thanks for the input guys! I've been reading and doing research on cms because I absolutely hate having a servo on the axle on a scaler, hahaha! I like the looks of the hb kit, just tryin to check out my options. So, I guess the hb kit is the way to go?

Well, GCM also makes a panhard mount. I figure it could be used with the rc4wd CMS as well as the GCM CMS (duh).

Here's the link to the GCM panhard mount Not the prettiest IMO, but it looks hella beefy.

But that said, you can buy the Hand Bros panhard mount (for the axle) seperately, but youd have to fab a mount forthe chassis side.