Caster Adjustment?

[Jerold]

I'm setting up the suspension on the Limitless for straight line speed runs and noticed some shims on the back of the upper control arms. It looks like I can swap those to the front to get more caster?

Is that the case?

If so I probably need to loosen the upper control arm which is like giving birth. Is it worth the hassle?

 

[SrC]

Yes, moving the shims forward will increase Caster angle. However, with Speed Running exclusively,, do you really need more caster to begin with??
Steering may become squirrely at speed.. . IMHO. Increasing Castor angle has no distinct advantage except for repetitive steering, more technical driving. (Off-road) Where understeer may be more of an an issue.
I keep mine in the stock position. Never felt I needed any more castor with my Lim or Infr.
With a few of my other Off-road rigs I have altered Castor.
Just me.

 

[Yonic]

You don’t need to loosen anything, you just pop them in and out.

The on-road cars are setup with minimum caster angle, as the chassis roll is minimal and the tires carcasses are flat. If you add caster you’ll notice you will have much less steering as when you turn just the tip of the tires will touch the road.

But for straight speed running.. I’m not sure what setup is preferable if any.

 

[Jerold]

Yes, moving the shims forward will increase Caster angle. However, with Speed Running exclusively,, do you really need more caster to begin with??
Steering may become squirrely at speed.. . IMHO. Increasing Castor angle has no distinct advantage except for repetitive steering, more technical driving. (Off-road) Where understeer may be more of an an issue.
I keep mine in the stock position. Never felt I needed any more castor with my Lim or Infr.
With a few of my other Off-road rigs I have altered Castor.
Just me.

More caster is better and helps it track straight. I'm not sure if it's worth the trouble though?

Tire Rack says:

Increasing the amount of positive caster will increase steering effort and straight line tracking, as well as improve high speed stability and cornering effectiveness. Positive caster also increases tire lean when cornering (almost like having more negative camber) as the steering angle is increased.


What's the downside to positive caster? If the vehicle doesn't have power steering, a noticeable increase in steering effort will be felt as positive caster is increased. Other than that, the effects of positive caster are pretty much "positive," especially increasing the lean of the tire when the vehicle is cornering while returning it to a more upright position when driving straight ahead.

With an off road or basher it probably doesn't matter that much because the suspension is in a constant state of change.

 

[parcou]

I'm setting up the suspension on the Limitless for straight line speed runs and noticed some shims on the back of the upper control arms. It looks like I can swap those to the front to get more caster?

Is that the case?

If so I probably need to loosen the upper control arm which is like giving birth. Is it worth the hassle?
View attachment 204757

Razor did a good video on this as a general overview how to adjust

 

[Jerold]

Razor did a good video on this as a general overview how to adjust

If I look on YouTube for Razor, it's not RC cars. Is it this one?

 

[TL01magic]

More caster is better and helps it track straight. I'm not sure if it's worth the trouble though?

Tire Rack says:


With an off road or basher it probably doesn't matter that much because the suspension is in a constant state of change.

My lim came stock with caster adjusted to almost the least amount possible; one thin shim of + caster.

Noticed that even at mild steering angles the contact patch was dramatically angled; I think much more than common with 1/10 TC from my experience.

Was showing through on tire wear as well.

I changed caster to be lowest possible and greatly reduced steering end points so no "extreme" tire angles when steering.

It likely does not take much positive caster to have the "natural" position of wheels be straight when under power.

I don't think the "extreme" caster on the Arrma "on road" cars is ideal. Not sure why they have it so extreme, and have it designed that there is little to no variability (from a ton of + caster to still too much + camber). maybe is because of pillow ball type connection for carriers means zero camber would not work.

I appreciate for straight line (which the lim seems primarily designed for) lots of caster is fine; but even for general parking lot bashing is too much caster imo and no ability to reduce to "normal" on road amounts kind of sucks. I think 0-4 degrees is typical for on-road (with turning lol)

simply put, straight is straight; more caster doesn't make more straight. VERY unlikely the car wobbles going forward....unlike my sloppy suspension mojave when driving in reverse....that's because tons of + caster and driving in reverse means is negative caster, and wheels basically go where ever slop allows. but going forward the wheels moreless "auto center" because of + caster.

thinking it through more, this is likely why there is so much caster on the on-road cars as well...to keep em driving straight as the suspension bits wear out and wow do they ever....even my lim with only about 6 packs of parking lot bashing is getting increasing slop.

 

[Jerold]

Not sure why they have it so extreme, and have it designed that there is little to no variability (from a ton of + caster to still too much + camber). maybe is because of pillow ball type connection for carriers means zero camber would not work.

The first pic above shows my caster at the least setting. My alignment was all messed up and nothing was even similar between the right and left sides. Nothing was right. I don't know that they have any consistency (specs) in their manufacturing process.

I spent a few hours tuning the suspension and alignment. If Arrma spent even an hour making it right, they would add $100 to each car.

With that said my, Traxxas Slash was pretty straight out of the box but you can only fiddle with the shock preload and front toe adjustments.

 

[Surchaufeur]

I noticed also the insane caster. You could shave the arms a bit to get less caster on the onroad cars. But thats will give more traxtion in the front because more tire contact and that is not what im looking for i have to much front traction

 

[TL01magic]

I noticed also the insane caster. You could shave the arms a bit to get less caster on the onroad cars. But thats will give more traxtion in the front because more tire contact and that is not what im looking for i have to much front traction

Which tires are you using?

Im using stock and find front end has WAY less traction than rear.

How do you have the rear suspension set up?

 

[SrC]

My lim came stock with caster adjusted to almost the least amount possible; one thin shim of + caster.

Noticed that even at mild steering angles the contact patch was dramatically angled; I think much more than common with 1/10 TC from my experience.

Was showing through on tire wear as well.

I changed caster to be lowest possible and greatly reduced steering end points so no "extreme" tire angles when steering.

It likely does not take much positive caster to have the "natural" position of wheels be straight when under power.

I don't think the "extreme" caster on the Arrma "on road" cars is ideal. Not sure why they have it so extreme, and have it designed that there is little to no variability (from a ton of + caster to still too much + camber). maybe is because of pillow ball type connection for carriers means zero camber would not work.

I appreciate for straight line (which the lim seems primarily designed for) lots of caster is fine; but even for general parking lot bashing is too much caster imo and no ability to reduce to "normal" on road amounts kind of sucks. I think 0-4 degrees is typical for on-road (with turning lol)

simply put, straight is straight; more caster doesn't make more straight. VERY unlikely the car wobbles going forward....unlike my sloppy suspension mojave when driving in reverse....that's because tons of + caster and driving in reverse means is negative caster, and wheels basically go where ever slop allows. but going forward the wheels moreless "auto center" because of + caster.

thinking it through more, this is likely why there is so much caster on the on-road cars as well...to keep em driving straight as the suspension bits wear out and wow do they ever....even my lim with only about 6 packs of parking lot bashing is getting increasing slop.

Yeah, too much castor will work against you. Stock castor IMHO seems a bit too much as it is. Why add more ?
My TC3 has minimal for example. A flatter tire patch, less tire scrub. Better tire wear.
Especially for speed running and even drifting.
With Off Road rigs, you want the tires' edges to "bite". Hence more castor angle and more Ackerman as well for the turns.

 

[Surchaufeur]

Which tires are you using?

Im using stock and find front end has WAY less traction than rear.

How do you have the rear suspension set up?

Silver hoons but with talion rear axles
My car is super stable even in cold temperatures. I doubts its because i made the rear sider to fit better the wheel arcs on the c8 body

 

[TL01magic]

Yeah, too much castor will work against you. Stock castor IMHO seems a bit too much as it is. Why add more ?
My TC3 has minimal for example. A flatter tire patch, less tire scrub. Better tire wear.
Especially for speed running and even drifting.
With Off Road rigs, you want the tires' edges to "bite". Hence more castor angle and more Ackerman as well for the turns.

Trying to remove caster, I have it a minimum possible without mods; and it still WAY more than I would want or think is needed.

For my mojave, I couldn't careless, just as long as it goes straight when going forward. tire wear / traction hardly a concern compared to on-road Lim.

Wish I had considered "basher build / design" of Arrma before getting the Lim. That said I should be able to "work" with it.

Silver hoons but with talion rear axles
My car is super stable even in cold temperatures. I doubts its because i made the rear sider to fit better the wheel arcs on the c8 body

huh; I can't make sense of that from my experience. Am pretty sure silver are hardest compound. Is your running surface really good? Am running on what I would call "medium aggregate pavement". so not too good imo and maybe partly explains my concerns with handling characteristics .

My lim is "super stable" as well, I think the wheelbase really adds to that stability...really is too stable I want mine to turn! lol Unless REALLY trying, I cannot kick out rear end due to steering angle. my lim pushes front much more than rear breaking traction

 

[Yonic]

Noticed that even at mild steering angles the contact patch was dramatically angled

Even with body roll (which happens while actually turning) or when standing still and turning the wheels?

I found the least caster to be just right on my Infraction, but as suggested above you can shave (or dremel) the top arms to reach even less caster

 

[SrC]

Trying to remove caster, I have it a minimum possible without mods; and it still WAY more than I would want or think is needed.

For my mojave, I couldn't careless, just as long as it goes straight when going forward. tire wear / traction hardly a concern compared to on-road Lim.

Wish I had considered "basher build / design" of Arrma before getting the Lim. That said I should be able to "work" with it.


huh; I can't make sense of that from my experience. Am pretty sure silver are hardest compound. Is your running surface really good? Am running on what I would call "medium aggregate pavement". so not too good imo and maybe partly explains my concerns with handling characteristics .

My lim is "super stable" as well, I think the wheelbase really adds to that stability...really is too stable I want mine to turn! lol Unless REALLY trying, I cannot kick out rear end due to steering angle. my lim pushes front much more than rear breaking traction

The Lim has an incredible amount of "Push". I say too much Caster is partly responsible, in addition to the long Wheelbase and narrow track width.
For very fast straight line running this is a distinct advantage/benefit however. .
Just that when drifting, the wheels have a hard time overcoming that inherent Push.
Shock preload and different spring rates can dial out a small amount of the push.

 

[Chrisfreshlife]

So i can remove/add these little guys to fix my tire issues?! Still new and learning and would like to fix this issue so the tire wear is even.

 

[PrerunninF150]

So i can remove/add these little guys to fix my tire issues?! Still new and learning and would like to fix this issue so the tire wear is even.

View attachment 216504

View attachment 216505

You may just need to adjust your camber with the pillow balls on the driver side.

 

[TL01magic]

So i can remove/add these little guys to fix my tire issues?! Still new and learning and would like to fix this issue so the tire wear is even.

View attachment 216504

View attachment 216505

I doubt that is from too much camber, and more likely from the caster.

Yes, you can move around those little spacers to change the caster, I believe caster is measured as angle of the wheel hub. Looks like you have all 3 spacers in the rear / to move the arm more forward (and in turn hub more upright).

not sure that'll fix the uneven tire wear but may reduce.

Myself, I greatly reduce the steering angle, as much as is possible for where I run. because of lack of grip in front i find myself throwing steering to max, so at least when I do front wheels are actually turning to max angle and chattering on edge across ground lol

Even with body roll (which happens while actually turning) or when standing still and turning the wheels?

I found the least caster to be just right on my Infraction, but as suggested above you can shave (or dremel) the top arms to reach even less caster

Good point, I will see if I can check what impact the suspension travel has on the caster.

I'll be checking out possible mods soon'ish, initial look doesn't seem like I'll be able to get the front hub even close to 100% vertical.