Kraton Pro-Line Street Fighter HP 3.8 Belted Tires on Kraton 4S

[VerticalChallenge]

After wearing through the stock tires I decided to upgrade to bigger belted models. I did upgrade my steering servo, and installed a Hot Racing Fixed Link Servo Saver (ATF48SH02) to handle the additional load, and am running the suggested FlySky FS-GT5 radio which greatly approved responsiveness particularly at longer distances. But even with these upgrades, the steering assembly just feels like it has a lot more slop and the vehicle is slow to respond. All the links have a bit of play and the cumulative effect is probably 10-15 degrees of wheel wiggle. Maybe this just didn't matter as much with lighter stock tires. Some other articles here suggest aluminum pivot balls may help. I am curious if anybody has solved steering problems running with bigger tires like this, or if I'm simply trying to run too big of tires on this vehicle. Any advice welcomed!

My Kraton 4S has become my favorite "pet" to accompany me on a walk around the neighborhood with my children. It's a surprisingly useful shepherd dog to keep little ones on bikes or scooters from getting to far ahead, crossing a driveway without looking for traffic, or blindly scooting through an intersection.

 

[SrC]

There will be some slop in the steering. Large wheels or smaller, will reveal slop regardless. You say steering is your issue. Is your servo strong enough for full travel at the bell crank? Check your servo endpoint adjustments if not. You may need more travel than the radio is dialed for. Larger wheels should give you more turn in control as long as the servo can handle it. Those 3.8 wheels are bigger and heavier than you had before? But a 25Kg (minimum) servo running at at 6v. should control those tires no issue. What servo is it? How strong is it?

 

[VonJarga]

I've been working on getting the slop out of my Outcast 4s' steering for awhile now, and the biggest improvements I've found came from upgrading:

1. Hot Racing Bellcrank
https://hot-racing.com/?partnumber=ATF4801;c=1385

2. Kimbrough 124 Servo Saver
https://www.amazon.com/Servo-Saver-Heavy-Duty-Gas/dp/B0006O1QQC

3. Possibly shimming your wheel hexes (for wheel wobble)
https://www.amazon.com/gp/product/B0036R4RQW/ref=ppx_yo_dt_b_asin_title_o08_s01?ie=UTF8&psc=1

4. Definitely get a stronger servo (mine is 36kg)

 

[Notorious J]

@VonJarga, a big part of the slop issue is the plastic balls they use in the steering links. I used AR330202 steel balls https://www.arrma-rc.com/part/AR330202 that are part of the rear camber links. I had to shave a bit off the top with a dremel. Used them on the inner and outer links of the steering. The plastic ones deform too quickly, and that's what increases the slop. That, along with the Hot Racing bell crank, has eliminated a ton of the play in the steering. The balls will only work in one of the four mounting holes of the HR bell crank, so you may lose a bit of the steering angle when done. I noticed no negligible difference.

 

[VonJarga]

@Notorious J that's good advice. I think I upgraded to the HR pivot balls (ATF160B02) and haven't had any issues with them. Have you played around with the camber positions on the HR bellcrank any? I'm curious how they would affect the steering vs adjusting the steering links themselves.

 

[Notorious J]

@Notorious J that's good advice. I think I upgraded to the HR pivot balls (ATF160B02) and haven't had any issues with them. Have you played around with the camber positions on the HR bellcrank any? I'm curious how they would affect the steering vs adjusting the steering links themselves.

Like I said, using the Arrma steel balls allowed me to only use one mounting point on the bell crank

 

[VonJarga]

Like I said, using the Arrma steel balls allowed me to only use one mounting point on the bell crankView attachment 128675

With the Hot Racing pivot balls and a TON of coercion I have mine in the inside middle hole. I was more asking how it would change the steering by moving those around?

 

[Notorious J]

With the Hot Racing pivot balls and a TON of coercion I have mine in the inside middle hole. I was more asking how it would change the steering by moving those around?

Great question, but I honestly don't know. The whole 3s steering system, including the c hubs and other links, is very sloppy to begin with. Not sure how much camber adjustments would effect the overall ride. If it was a real racing buggy, maybe the tolerances might play a bigger part. The reason I'm taking some small steps to improve my steering is to help keep it straight in speed runs. As a basher, I never worried to much about it.