Chassis Brace Material Question
 

Greetings all,

I searched around and could not find the info I was looking for, but I was wondering about the general ideas behind chassis braces and the material. Cost aside, I have seen that many race vehicles are running polymer braces while bashers are upgrading to aluminum. For obvious impact reasons this makes sense, but there was a discussion I cannot find about needing a certain amount of chassis flex to improve traction on rough terrain, and that very rigid braces can actually make the car perform worse.

On my Lasernut I have both front and rear plastic braces, as well as this top brace. I really dislike the top brace and was thinking that maybe two "upgraded" lower braces for the front and rear bulkheads, and then omit the top strap and get a much smaller diff top plate and steering top plate. Maybe aluminum front and rear braces would be enough for rock racing?

s

When you use the term "Rock Racing", are you truly "racing" against other people or just bashing around by yourself?

I currently club race the SCT410 which shares similar geometry with your truck. I remove both the center and rear chassis braces in order to maximize chassis flex to improve traction/handling. The trade off is that if I take a hard nose dive then I am more likely to bend the center drive shaft. To me, it's definitely worth the risk in order to have an advantage against my competition, but if I was bashing around all by myself, then I wouldn't take the risk and I would re-install the chassis braces... only time I would upgrade the braces to aluminum is if I was damaging the braces often enough.

Just because there are upgrades out there, doesn't necessarily mean they are necessary. It all depends on your specific needs.

Thanks Bill,

There are a few cars on the track, and we are slowly adding to the group, but during the week I'm often just practicing by myself. It's on a new track we built in the desert, and it's pretty awesome, but very challenging. It's chunky, rough, with tight turns and choppy elevation changes. A lap timer is next to get better information about the impact of changes being made. We have some plans to head out to So Cal for some racing, and they will in turn come to our track in hopes that we can grow a larger group in the southwest region.

Currently I'm running the Lasernut as my main platform, but I keep making small adjustments to my Tekno to see if I can get it better suited for our track. The Lasernut has a massive top brace connecting each bulkhead and tying in the center diff. Along with that are two additional braces from each bulkhead and tying into the frame. It seems ideally suited for bashing, which is something I do not do, so I'm wondering if I can remove it, but we have some pretty nasty rocks embedded in the track, and they can cause substantial damage at times. I'm guessing I may have to leave that top brace on for now.

s

Bill,

Here is a link to the track we are running. Still more work to do in adding a few sections, but it's been rather interesting so far. I think I'll stay with the top brace as you suggested.

Desert Racetrack - Mojave Valley RC Adventures


https://cimg9.ibsrv.net/gimg/www.rct...bb6e25044a.jpg
Modified Losi Lasernut with Ottsix USD Sticky's on Vanquish beadlocks and 850's SLW hubs.

With that type of racing, you don't really need to worry about chassis flex. Chassis flex is a bigger concern when your on high tractions tracks. In your racing, you would never get enough traction to cause your chassis to flex unless it was made of balsa wood. The dirt is too lose and your car is bouncing too much. For a top plate, it will have to be anodized aluminum for strength. For bashing, weight isn't an issue, so they will beef it up with aluminum. If you are racing, weight will be an issue. You can get a piece of carbon fiber and make your own brace. Therefore, you can make it to any design you want. You can find small carbon fiber sheets on Amazon and Ebay. They don't cost that much and you can get it in a variety of thicknesses.

As much as I would like to say that carbon graphite sheets is easy to cut and shape I will be absolutely wrong. With a proper hepa filter vacuum setup like a ProTeam super coach HEPA 10 amp 10 quart I’d feel safe with the thing sucking air through a base of a cutting solution like a dremel mini drill press mounted securely to a bench using carbide grout removal bits will make cutting forms very easy and the carbide grout bits can be plunged as well for pilot holes. These bits make a nice finished edge however are rather expensive for the size of said carbide content.

This kind of set up can be used to cut 3mm thick sheets, or plan on replacing the bit often on thicker stock.

Done enough to know that yeah they were right about the 1/16 grout removal bits they actually last longer than the 1/8 and make finer cuts.

I also was under the impression that the TLR SCTe uses the same steering post top brace. Correct me if I am wrong.
TLR331008

that U4 top brace looks to be one piece, however looks modifiable to mount on top of similar plate using that center hole.

I need to dig around a bit more on the TLR line and see what they have, but the TLR 3.0 SCTE doesn't appear to have a top brace. This sort of my start of the thought process, that if this SCTE truck does not have one, maybe can I skip it.

I understand what you guys mean about the traction level, and that's the concept that stands out to me the most at the moment; we have very poor traction on this track. It's part of the fun of the track, but I can see how it would negate any advantages of running without a brace. As Bill mentioned, if my original braces fail, then I'll look into the upgrade.

Anyhow, thanks for the comments and ideas. Helps point me in the right direction.

s

I wish we had tracks out her like that. The way tracks are being built now might as well be considered on-road racing with jumps. We call that Motard racing (Google it). Low traction with a choppy track was REAL off-roading. I also miss the rhythm sections.

I hear ya. It's not as big or fancy as most tracks, but it is so much fun to drive and really is challenging at speed. It's almost impossible to hold the lead for more than one lap, so it's very competitive and makes for some spectacular crashes.

I'm looking hard at building a 1/10 Losi Baja Rey to see if I can tune to to handle the track.

s

Here is a look under the hood.


https://cimg0.ibsrv.net/gimg/www.rct...209ec0ba48.jpg
Losi Lasernut with some mods.

So that center brace.. You don’t think it can be re-fabricated or modified to lay on top of the scte brace and bolt into the center hole. The Pro DB uses that same center as well. All it is acting like is a bar that can go from rear bulkhead to front top brace with center support it appears

The SCTe plastic one looks just like it minus the center conglomeration.

I agree with running without if it is a positive change.

I actually thought about making a bar that attaches the rear to the front on my SCTe



https://cimg5.ibsrv.net/gimg/www.rct...45ab8d7f4.jpeg

The scte could actually use that center mounting style just for simple protection and have considered getting U4 gearbox set so I can see if that center works.