Yokomo YZ-2

[Allan1875]

Originally Posted by timoxx4

Yeah the RB6 has a ackerman plate that everyone was reversing to place the ball studs back more to calm the steering down as its a rather twitchy car to begin with. I pushed mine one step further and made a alloy one on the milling machine that placed the ball studs even further back and it made the steering even more settled down.

I also race 1/8th nitro buggy Mugen MBX7R and its the same. Ackerman links back = calmer steering. Its just how those particular cars work I guess. And I have just always thought that's how all cars react to ackerman changes in the same way but I guess it can be opposite.

So after speaking to a couple of people, and looking into a couple of different cars, it's apparently due to the pivot point of the bell crank.

For example, I looked at the B5M manual and it suggests that you remove shims and move the ballstud further back to calm the steering, however on this car, the pivot point for the bell crank is on the opposite side (closer to the rear of the car).

Still doesn't clear up the confusion with the RB6 as when I looked at the manual (for the 2015), it shows the pivot point in the same position as the YZ2 (closer to the front of the car). This could still be to do with angles of the link though.

One thing I can tell you for definite, is that when I went from 3mm to 4mm under the ballstud on astro, it really calmed the car down on low speed steering.

Love to know if anyone knows more on this subject though as I find it interesting.

The mugen as per the BMAX4 have the pivot point behind the ackermann plate, therefore back = calm, forward = aggressive.

[Adam F]

Pushing the balljoint towards the pivot will reduce Ackerman.

So spacing it forward is reducing on the yz2.

[Allan1875]

Originally Posted by Adam F

Pushing the balljoint towards the pivot will reduce Ackerman.

So spacing it forward is reducing on the yz2.

Reducing ackermann means making it more aggressive. Do you mean increase? Or do you agree that 4mm spacers should be more aggressive than 2mm.

Lets not confuse this further.

[timoxx4]

Don't worry. I was already confused It must increase ackerman moving closer to the pivot point as that's the only thing that seems right ?

[Adam F]

Chassis dynamics is not my bag, but... Are you sure?

Always thought that less Ackerman meant that the inner wheel carved a larger arc and that this was what reduced the "snatchy" feeling when turning.

So increased Ackerman meant the inside wheel traces a smaller arc?

[Allan1875]

Double post

[Allan1875]

Originally Posted by Adam F

Chassis dynamics is not my bag, but... Are you sure?

Always thought that less Ackerman meant that the inner wheel carved a larger arc and that this was what reduced the "snatchy" feeling when turning.

So increased Ackerman meant the inside wheel traces a smaller arc?

Yes and no, think it's getting confused. More ackermann means the inside wheel traces a tighter arc and the 2 wheels have a more severe angle difference when turning. This stops the outside tyre scrubbing as this wheel needs to trace a long arc.

By reducing ackermann, the wheels turn at an angle that is much closer together, making the car edgy and snatchy. This is the reason that increasing ackermann, calms the response of the steering.

Thats why:

Originally Posted by Adam F

Pushing the balljoint towards the pivot will reduce Ackerman.

So spacing it forward is reducing on the yz2.

When we go to 4mm to calm the steering, we are pushing the ball joint towards the pivot to increase Ackermann, not reduce it.

I still want to look at this on my desk but from my experience of driving the car, 4mm definitely calmed my steering response over kit setting.

[ralphee]

TBH lads, i was told the 4mm would make it more aggresive, rule of thumb thinking? So i do run 4mm after trying it, and it does seem less aggresive on initial response!

Lee

[danDanEFC]

I am an idiot with thumbs made of concrete.

When I put the 4mm on the metaly steery thingy car initial steering feels smoother.

The reason being we have appeased the 'initial steering God with the offering of more washers'

[Allan1875]

Originally Posted by danDanEFC

I am an idiot with thumbs made of concrete.

When I put the 4mm on the metaly steery thingy car initial steering feels smoother.

The reason being we have appeased the 'initial steering God with the offering of more washers'

Best post so far.

[Ross]

Originally Posted by danDanEFC

I am an idiot with thumbs made of concrete.

When I put the 4mm on the metaly steery thingy car initial steering feels smoother.

The reason being we have appeased the 'initial steering God with the offering of more washers'

😂😂😂😂😂

[Adam F]

http://www.rctek.com/technical/handl...principle.html

Ok... now I'm lost..

[RDG 40]

Ive only had one experience of this at a regional i was bit tame on steering, with 4mm. I looked at mates car who ran kit 3mm.

Once i went 3 the car was transformed i had steering.

So yz wise i would agree 4 calms and less makes more agressive.

Russ

[charlesk]

Not a YZ2 owner so haven't had a chance to study/play with a YZ2, but ackerman geometry principles apply the same nomatter what the car design is.To try and make things easier for understanding, there is 1 thing to remember:

on rcs we can alter the ackerman characteristics of the steering system by altering the angle of the steering links relative to the imaginary line between the steering arm link points.

The closer to parallel the links are to the imaginary line between the steeling arm pivots, the less ackerman angle is induced during steering so a more aggressive feel is given to the steering (outer wheel closer to steering angle to the inner)

On the aforementioned RB6 pointing the rack backwards increases the angle of the steering links hence the steering calms down.

On the YZ2, because of the different rack style what I suspect happens is that by removing washers the angle of the links becomes shallower hence the steering more aggressive.

Ultimately it come down to the fact that the YZ2 has a different rack/steering system geometry to the Bmax/Rb6 hence why the same adjustment does have the same effect but its reversed...

[Allan1875]

Originally Posted by charlesk

Not a YZ2 owner so haven't had a chance to study/play with a YZ2, but ackerman geometry principles apply the same nomatter what the car design is.To try and make things easier for understanding, there is 1 thing to remember:

on rcs we can alter the ackerman characteristics of the steering system by altering the angle of the steering links relative to the imaginary line between the steering arm link points.

The closer to parallel the links are to the imaginary line between the steeling arm pivots, the less ackerman angle is induced during steering so a more aggressive feel is given to the steering (outer wheel closer to steering angle to the inner)

On the aforementioned RB6 pointing the rack backwards increases the angle of the steering links hence the steering calms down.

On the YZ2, because of the different rack style what I suspect happens is that by removing washers the angle of the links becomes shallower hence the steering more aggressive.

Ultimately it come down to the fact that the YZ2 has a different rack/steering system geometry to the Bmax/Rb6 hence why the same adjustment does have the same effect but its reversed...

This kinda goes along the lines of what most of the things I read yesterday said. If in doubt just make the change on your bench and you can tell by eye!

[timoxx4]

Originally Posted by charlesk

On the aforementioned RB6 pointing the rack backwards increases the angle of the steering links hence the steering calms down.

Actually pointing the rack backwards makes the links more straight on the RB6. I have a RB6 and moving the links back straightens them out. Pushing them forward makes them more angled.

And for some strange reason having the links back made the steering less aggressive on that car ???? It should have made it worse going by what I have read about having less ackerman.

Hence why I am a little bit confused with all this.

And on the Bmax4 dosent moving the links back also straighten them out ? Thus should be more aggressive ?

[Allan1875]

Right lads, wanted to measure the ackermann so we could put this to rest for the YZ2 at least.

Here are the measurements for the wheel angles:

0mm washers - In 40 degrees, Out 29 degrees.
4mm washers - In 40 degrees, Out 24 degrees.

As you can see, 4mm has a bigger difference between the wheels, which is why it is less aggressive, as it has more ackermann.

Obviously the inside wheel doesn't change as this was on full lock.

[neallewis]

Originally Posted by Allan1875

Right lads, wanted to measure the ackermann so we could put this to rest for the YZ2 at least.

Here are the measurements for the wheel angles:

0mm washers - In 40 degrees, Out 29 degrees.
4mm washers - In 40 degrees, Out 24 degrees.

As you can see, 4mm has a bigger difference between the wheels, which is why it is less aggressive, as it has more ackermann.

Obviously the inside wheel doesn't change as this was on full lock.

[discostu]

It's pretty simple moving the inside link closer to the rear of the car calms the steering feel Down

[discostu]

Just saying