Steering Mods for SRB’s Advice Please.

[Grumpy pants]

I want to upgrade the steering on my Rere Sand Scorcher and there are 1 of 2 ways to go-

1. Move the servo into the front of the battery box, upgrade the servo saver £11 and boom- the link below was the prompt! 

 

[Grumpy pants]

Or option 2,

Stand the servo upright and use the Super Champ parts I have already bought ( I just need a RR body post £10)

This link is the inspiration-

https://www.tamiyaclub.com/showroom_model.asp?cid=131948&id=5045

I need to be resourceful and I’d like to keep the radio box.

Whats everyone’s thoughts, which is the better way to go or is there an alternative route I should be considering 👍

[Grumpy pants]

Option 1- I really like as there are a lot less moving parts and the steering is directly connected to the servo.

Option 2- I like because I’ve spent about £50 picking up the SC parts and they are NOS and they look and feel well made. 

[Grumpy pants]

Suggested Servo Saver upgrade-

 

[Mad Ax]

A good question and I'll be interested to see what suggestions come up.

Now, not to want to throw a fallen tree onto the rails in front of your train of thought, but there is another option, one I've been considering, either for my SRB Lightweight project that I've been playing with on-and-off for the last 3-4 years, or for an SRB Unlimited idea that I've been brainstorming but not actually started work on yet.  My plan was to utilise the ubiquitous linked bell crank system found on most modern buggies.  I've got enough spare front ends lying around to make something like this work.

Drilling holes to mount the crank posts would be easy, as would making a custom link to join them together.  Adding a top deck to support the tops of the posts would be harder and might mean doing away with the radio box (either my Lightweight nor my possible Unlimited will have radio boxes so that doesn't matter to me).  Without a top deck I'd worry the posts would rip out of the chassis.

The downside of this is I'm not actually sure if there is a point to it with the SRB's trailing arm front suspension, because the wheel doesn't describe an outward arc like it does with more conventional double-wishbone suspension.  In fact having shorter steering arms might increase bump steer on an SRB front-end.  Which is partly why I'm considering it more for my Unlimited project, which will likely have a double wishbone front end.

 

Off the top of my head, I'm thinking the best bet is to mock up both options on the workbench and see what gives the best results in terms of bump steer and ackerman.  Bump steer is probably more important and the Super Champ setup looks perfect for that.  I think you could utilise that with the radio box if you're prepared to jiggle around your electrics a bit and maybe run shorties, saddles or soft packs.  I'm not sure (without at least getting out some pens and paper) if the SC setup improves ackerman.  I'd be inclined to mock up some other options such as a lay-down servo, stand-up servo and even a stand-up servo inline with the axle so the servo horn turns with the steering arms and not against them (a la SC bellcrank).

But then again I'm no expert in chassis geometry so maybe someone else will come along soon with some other neat suggestions

[KEV THE REV]

Just throwing this into the mix , no radio box , but maybe something in there that you like - direct steering  . The small deck at the rear housed the RX and ESC , stick pack laid longways down the chassis with retainer fitted in the centre made from ball links.

https://www.tamiyaclub.com/showroom_model.asp?cid=79145&id=5280

[TurnipJF]

How about a combination approach?

A small but strong metal geared mini servo mounted upright in a cutout in the front portion of the radio box, driving either the SC or stock SS servo saver via a short pushrod, thus eliminating the slop inherent in the long skinny bent SS pushrod while keeping the radio box and your NOS parts in play.

I'd also consider eliminating more slop by doing away with the rubber bungs between chassis and radio box, and hard-mounting the radio box to the chassis with bolts for a wobble-free connection.

[TWINSET]

58 minutes ago, KEV THE REV said:

Just throwing this into the mix , no radio box , but maybe something in there that you like - direct steering  . The small deck at the rear housed the RX and ESC , stick pack laid longways down the chassis with retainer fitted in the centre made from ball links.

 

Direct worked fine

There was also a servo mounting wedge/ramp made by one of the hop-up companies, which fitted between the servo and the chassis so the servo horn could face down, but I can't find a pic of that at the mo...

[TWINSET]

Here's the wedge/ramp thingy;

 

From http://www.toybaron.com/MIPreference.htm

 

[TurnipJF]

As I understand it, the point of the wedge/ramp thingy is to get the servo saver and  inner tierod attachment points as low to the chassis as possible in order to keep the tierods horizontal and avoid bump steer.

Can the same thing not be achieved by making the outer tierod attachment points higher, mounting the ball connectors on the top of the uprights instead of underneath, possibly with a spacer if required?

[ruebiracer]

Here´is my new Setup, 

using a better servo, Hi torque servo saver inside Rc-box and the super champ servo saver setup with a modified SS body post. Servo saver is locked by full compression of spring. Liked to use the High torque saver inside the radio box because of dirt, sand etc., that were Always locking over time the original SS saver. To get full steering angle like on the SS, I screwed on an adapting plate to original SS Lever arm geometry. No real bump steer here. Chassis is original FRP+ extra aluminum reinforcing chassis homemade. So very little flex here, that affects the steering effect. Due to sickness, final testing on the beach ahd to be skipped in Octobre, sadly. But it´s a similar setup as Raman recommended in a similar thread here, have to dig it out...

Br,

Matthias

[Grumpy pants]

Amazing feed back and input gang in just 12 hours, it’s has been really helpful.

I’ve put my request in now with my TC engineer 😉 (AKA Turnip)  who has done a phenomenal job of putting this altogether for me. 

[Shodog]

Some good steering set up ideas. My thoughts are that you have to keep the steering rods as low and close to the chassis to minimize bump steer. On my runner rough rider I use the Super Champ servo saver with Tecnacraft titanium rods with Dubro ball links.  

 

 

[yogi-bear]

1 hour ago, Shodog said:

Some good steering set up ideas. My thoughts are that you have to keep the steering rods as low and close to the chassis to minimize bump steer. On my runner rough rider I use the Super Champ servo saver with Tecnacraft titanium rods with Dubro ball links.  

 

 

any chance of a better pic of the rims you are using?

[ruebiracer]

On ‎12‎/‎14‎/‎2018 at 2:49 AM, yogi-bear said:

any chance of a better pic of the rims you are using?

And also some Background about the coil over springs and retainers on the original shocks?

[Raman36]

On 12/13/2018 at 8:04 AM, ruebiracer said:

Here´is my new Setup, 

using a better servo, Hi torque servo saver inside Rc-box and the super champ servo saver setup with a modified SS body post. Servo saver is locked by full compression of spring. Liked to use the High torque saver inside the radio box because of dirt, sand etc., that were Always locking over time the original SS saver. To get full steering angle like on the SS, I screwed on an adapting plate to original SS Lever arm geometry. No real bump steer here. Chassis is original FRP+ extra aluminum reinforcing chassis homemade. So very little flex here, that affects the steering effect. Due to sickness, final testing on the beach ahd to be skipped in Octobre, sadly. But it´s a similar setup as Raman recommended in a similar thread here, have to dig it out...

Br,

Matthias

Very nice Mattias!! 

Best mod for staying as close to original as possible. The extensions greatly improve steering radius / geometry 

[ruebiracer]

10 hours ago, Raman36 said:

Very nice Mattias!! 

Best mod for staying as close to original as possible. The extensions greatly improve steering radius / geometry 

Thank you Raman, as you promised it works very nice! For my purpose I like to keep everything in the Radio box. So cleaning the Scorcher after a beach run is safe and easy with water. In case, pop off the steering linkage, the 3 motor plugs and the 2 screws underneath and take away the complete box for cleaning. I don´t know any other RC car which makes this possible besides an SRB...

But of course there are many ways to get to a decent steering, as the thread shows!

[Shodog]

On 12/15/2018 at 7:37 AM, ruebiracer said:

And also some Background about the coil over springs and retainers on the original shocks?

Those are made by CRP.  Rims are vintage RCH wheel covers