I’m trying to make an Aluminum Boost Chassis any help would be nice

[jamesx65]

My Boost chassis snapped in two as well as my center steering link. I’m looking to replace the chassis by making an Aluminum replacement for around $20. Any help would be great (links, pics, Etc.) to help me reference.

As far as the center steering link goes I’m probably going to get the RPM Servo Saver Delete Kit. Anyone with experience with this : please let me know any pros and cons with it.

Thanks,
Ryan

 

[i_r_beej]

I can't offer any guidance on the chassis project other than to measure the existing one and get as close to that as you can. I think another poster in the Boost sub-forum is working on making a carbon-composite chassis.

As for the RPM "servo saver eliminator" steering bellcrank-- there are no cons. I've installed that kit on two ECX cars and love it. You can purchase bearings to press into the bellcrank (dims are given in the RPM instructions) but I don't think they make a huge difference in performance over the supplied Delrin bushings.

However, I WOULD highly recommend you get a metal-geared servo. I continue to use a plastic servo arm as a "sacrificial" part in the event of a major hit to the front end, but I also use RPM heavy duty rod ends (ball cups) and Associated titanium turnbuckles and the ballcups also pop off in the event of frontal impacts. But definitely get the metal-geared servo.

 

[jamesx65]

I can't offer any guidance on the chassis project other than to measure the existing one and get as close to that as you can. I think another poster in the Boost sub-forum is working on making a carbon-composite chassis.

As for the RPM "servo saver eliminator" steering bellcrank-- there are no cons. I've installed that kit on two ECX cars and love it. You can purchase bearings to press into the bellcrank (dims are given in the RPM instructions) but I don't think they make a huge difference in performance over the supplied Delrin bushings.

However, I WOULD highly recommend you get a metal-geared servo. I continue to use a plastic servo arm as a "sacrificial" part in the event of a major hit to the front end, but I also use RPM heavy duty rod ends (ball cups) and Associated titanium turnbuckles and the ballcups also pop off in the event of frontal impacts. But definitely get the metal-geared servo.

Thank you for the info. Any “cheap” well made metal geared servos you can suggest? and What exactly does the servo delete do in terms of performance?

 

[i_r_beej]

The stock bellcrank incorporates a "c-clip" type spring that allows for the wheels to move independently (to a degree) of the servo arm-- this is to absorb the energy of impacts to the wheels. However, the spring is relatively weak and easily overcome by the friction of tires on the driving surface! Loose dirt is okay, but asphalt or indoor carpet is the worst. The front wheels turn side-to-side very little, giving the appearance of a broken servo or dual-rate turned down.

The RPM steering bellcrank system is like that found on race cars (like my TLR 22 buggy and truck): there is no mechanism to absorb shock. The result is that you get much more positive steering with little "slop" or play.

I've been racing indoors for almost two years now on "astroturf" and carpet on tracks that feature sharp turns, multiple jumps, etc. with both the RPM system on my Boost and Circuit cars as well as my TLR cars and have not yet suffered a broken or damaged servo despite may crashes into walls, barriers, etc. Like I mentioned earlier, I stick with a plastic servo arm with the idea being that the plastic splines in the arm will give before the servo's gear train. So far this has happened once, demonstrating that the idea is a sound strategy. Steering ball cups also pop free on occasion.

As for cheap metal geared servos? I know that there are several folks here that have purchased really cheap MG servos for about US$10 on Amazon or Ebay but have reported lackluster performance and other glitches (including the servo just burning out/failing completely).

I personally use HobbyKing's Turnigy 1258TG servos in a couple of my cars (Circuit and TLR 22T stadium truck) and a Savox 1251MG in my TLR 22 buggy. The Turnigy servos were a great value, matching the performance of the Savox 1258TG servos at about half the price but it seems that they are no longer offered by HobbyKing. I think their "Trackstar" house brand has replaced the Turnigy brand-- the specs seem similar, as do the prices. Other than that I can't offer any other recommendation other than to invest in decent electronics. If you changes cars, move the electronics. "Buy right or buy twice!"

 

[jamesx65]

The stock bellcrank incorporates a "c-clip" type spring that allows for the wheels to move independently (to a degree) of the servo arm-- this is to absorb the energy of impacts to the wheels. However, the spring is relatively weak and easily overcome by the friction of tires on the driving surface! Loose dirt is okay, but asphalt or indoor carpet is the worst. The front wheels turn side-to-side very little, giving the appearance of a broken servo or dual-rate turned down.

The RPM steering bellcrank system is like that found on race cars (like my TLR 22 buggy and truck): there is no mechanism to absorb shock. The result is that you get much more positive steering with little "slop" or play.

I've been racing indoors for almost two years now on "astroturf" and carpet on tracks that feature sharp turns, multiple jumps, etc. with both the RPM system on my Boost and Circuit cars as well as my TLR cars and have not yet suffered a broken or damaged servo despite may crashes into walls, barriers, etc. Like I mentioned earlier, I stick with a plastic servo arm with the idea being that the plastic splines in the arm will give before the servo's gear train. So far this has happened once, demonstrating that the idea is a sound strategy. Steering ball cups also pop free on occasion.

As for cheap metal geared servos? I know that there are several folks here that have purchased really cheap MG servos for about US$10 on Amazon or Ebay but have reported lackluster performance and other glitches (including the servo just burning out/failing completely).

I personally use HobbyKing's Turnigy 1258TG servos in a couple of my cars (Circuit and TLR 22T stadium truck) and a Savox 1251MG in my TLR 22 buggy. The Turnigy servos were a great value, matching the performance of the Savox 1258TG servos at about half the price but it seems that they are no longer offered by HobbyKing. I think their "Trackstar" house brand has replaced the Turnigy brand-- the specs seem similar, as do the prices. Other than that I can't offer any other recommendation other than to invest in decent electronics. If you changes cars, move the electronics. "Buy right or buy twice!"

Thank you for the explanation and recommendations. Very much appreciated.

 

[KyleRC]

Thank you for the info. Any “cheap” well made metal geared servos you can suggest? and What exactly does the servo delete do in terms of performance?

Jx Pdi-6113 is a great servo I run two of these in my racing cars I race a torment with one and it has abundance of torque AND speed it is just well perfect for anything. It is NOT WATERPROOF but mine survived a jump into a small pool but my car has a cover over the receiver and servo but there’s plenty of space for the water to get in. Not to mention it is good looking. It is core less so it lasts long quick response and torque. I even run one in my Associated B6D and I can get constant lower 17 second runs around the track.

Not to mention most servos with these specifications are around $50.

 

[jazztaz]

I snapped 2 Boost and 1 Circut chassis' all by the two rear ears. I then created a reinforcing plate out of 1/16 sheet aluminum. That was 4 years ago and ever since I screwed the aluminum plate to the bottom, it has not broken. I used a piece of paper to sketch out the plate from the bottom screw holes, then counter sunk the holes then used the existing screws as shown in the picture.