What Are the Advantages a Good Chassis has over a Bad One

[Super Clodbuster Junkie]

Hello,

Please tell me why good chassis are better than bad ones in detail.

[Nicadraus]

Because Good Chassis are "good" and bad chassis are "bad"... 

Seriously, good chassis are stiffer than the bad ones. They are better made than just plastic. Materials like FRP (fiber reinforced plastic), CF (carbon fiber) and CRP (carbon reinforced plastic). Bad chassis tend to flex a lot, some are made of brittle plastic while the others have very weak points. Although some plastic chassis can be reinforced with either carbon fiber parts or aluminum as seen in most touring cars (TT, TA, FF, TB series) and some buggies.

[87lc2]

Exactly what Nicadraus said, a good chassis is stiff and let's the suspension to it's job whereas a poor chassis flexes too much and takes at least some of the suspension action out of the equation.  

Assuming you're not just talking about the chassis itself, the suspension contributes a lot to a good or bad complete chassis.  You could have the most rigid, low center of gravity chassis in the world, but without proper suspension damping, compression, and geometry it will handle terribly.  A good overall chassis does not always mean a complex system either, there are some very good cars out there with very simple suspension that work extremely well due to proper geometry and tuning options.  Of course a good chassis/suspension system is different depending on what you're doing with it as well.  What works for a touring car will not work for a short course truck and vice versa.

[Yalson]

Other things to consider in whether a chassis is "good" or "bad":

1. Ease of access. How easy is it to build, repair and access important parts?

2. How easy is it to "dial in"? A good chassis will have numerous areas where you can make changes to make it handle better in different conditions, and will have a wider "window" where it is usable and handles sufficiently well to be effective.

3. Spares availability. No chassis is any good if it is forever stuck on the shelf because you've broken something and you can't get spares to replace it.

4. Development potential. As you get more used to it and better at using it, your chassis should hopefully have enough upgrades available to be able to evolve with you for at least a few years.

5. Retro-compatibility. Your chassis may handle like a dream, but if you have boxes full of usable wheels and tyres, for example, and they don't fit your new machine, you've effectively thrown a whole load of investment down the drain

[Fuijo]

A good chassis is one you like. A bad chassis is one you don't.

 

As far as track cars go though, it isn't so much what you've got, as how you drive it. Every couple of weeks I get to watch @GooneyBird seriously embarrass 95% of the owners of high-end TC's including Xray's and TRF's etc. With

his ancient TT-01 running a Carson Cup Machine. Almost every session he's the fastest person lapping the track by quite some margin.

[Bromley]

Good or Bad isn't really the whole story. Some are just more fun, consider CW-01, not the last word in dynamics I think you'll agree!

Some make better bashers...DT02/3. Some better racers TRF****. Some look just right Avante/Top Force. Others are just better for modding CC01.

[Theibault]

The good ones have halos and the bad ones have horns. I think it comes down to personal preference unless you are competing, then some of what has been said above applies.

[Super Clodbuster Junkie]

Thank you for the info!

[SuperChamp82]

The racing purists are right re chassis rigidity requiring finely balanced suspension geometry, wheel size / alignment and tyre styles / compounds.

@Bromley is spot on for everyone else - and I personally think there’s no such thing as a bad Tamiya chassis ... just varied degrees of fun seeing how one differs from others, especially when you finally run what you’ve built !

[wolfdogstinkus]

More space for more lipo's. and room to move them around in chassis. 

Whats better than 7volts?, 14. 

[Saito2]

I'll toss this out from something I read years ago in RC Car Action. I'm not sure if there is any truth to it so feel free to correct me. Its just more fodder for the discussion. After the first RC10 boom settled a bit, there was a big rush toward flat carbon graphite chassis. Losi's JR-X2 was a big deal because it came with one in the kit. Associated added the RC10 Graphite along side the aluminum tub version. Then, after awhile, team drivers started going back to the aluminum tub (albeit often trimmed down to save weight). I recall the reasoning was that the graphite was too stiff and unforgiving, making the cars "edgy" and ultra responsive. The aluminum tub was stiff enough but still a little more "forgiving" to driver inputs. Any truth to any of that?

 

[Juggular]

Assuming "chassis" to mean broadly,  

[Arms] To use buggies as an example, short-armed DF01 has limited suspension travel.  My Hummer barely makes a mediocre rally car.  Which is why my impression of DF01 was bad (not anymore).  On the other hand, DF01 with longer arms like Manta Ray, Blazing Star, Top Force make good buggies.  I just got a used chassis, and that improved my opinion of DF01 a lot.  Contrary to the common belief, a car flying in the air isn't accelerating.  Tires need to be on the ground to transmit power and longer arms could do that better.  XV-01 below is a rally car chassis.  For its size, it's got long arms.  

[Toe in]  At the rear, toe-in would help with stability.  Old cars don't have the rear toe angles (besides, you can't have a toe-in for a rigid axle like the Hornet).  New buggies like DT02, DT03 have rear toe-in.  But adjustable rear toe angles tend to be available only for the expensive chassis (often by replacing the hub carriers).  I have a vague suspicion that the rear toe-in helps with the Ackerman thing, because the outer wheel is more aligned with the turning circle.  And that outer wheel gets more weight.  The inner wheel would be likely to lose some grip because of the greater slip angle, but the inside gets less weight anyway. (of course, I could be wrong about the whole toe-in and the Ackerman)  Anyway, rear toe-in seems to help in general, and "better" chassis often have it.   

[Camber]  Camber helps at corners.  Again, this is often not available for inexpensive kits.  

And below is too much camber.  

[Caster]  This isn't really adjustable.  An easy way think about this is how much the front shocks lean back.  The caster angle helps with stability and shock absorption.  Old or new, many cars have some caster angle.  (Oddly, the Fox, Falcon and Hotshot have a noticeable caster angle.  But recent Konghead doesn't have any.  Not that G6 is a "good chassis.")  Generally, good ones have some caster, while simpler basher chassis don't have it.    

[Differential]  Better chassis tend to come with ball differentials.  Limited-Slip-Differentials like ball diffs are almost always better than regular mechanical differential that "unloads."  Unloading is when one wheel bounces off the ground, and that causes both wheels to lose power.  LSD keeps one wheel on the ground working.  For on-road cars and light-weight buggies, Anti-Wear grease on mechanical differentials works well.  

[Suspensions]  Most cars these days have double wishbone suspension.  But Tamiya's older chassis used all kinds of different suspensions.  Single wishbone like the Grasshopper would have that terrible "bump steer."  It also had a rigid axle in the back that didn't pivot sideways.  The Grasshopper and the 1984 Pajero have the worst suspension.  Be that as it may, a bit of "wildness" in the Grasshopper made it fun.  The Frog had rear swing arms, FAV had front and rear swing arms, Sand Scorcher had front double swing arms and single wishbone suspension at the rear.  All could be viewed as "inferior" to the double wishbone, but, I found the variety interesting.  

[Oil shocks]  Smooth shocks are obviously better than too tight or too loose shocks.  Expensive ones tend to be made precisely with aluminum body, fluorine coated shafts and better o-rings, etc.  And shock towers have multiple mounting points for adjustability.  But all that is useless because Tamiya instructs you to set it like a rock. (I'm only half kidding) 

 

[Steering mechanism]  TRF201 is a race-worthy 2WD.  DN01 is a cheaper version of it.  But the steering linkages pivot on 6 bearings (only 2 bearings are included).  It's very well balanced so that you shake the car lightly without the servo in it, it will smoothly swing.  The Frog would have one side linkage longer than the other, so it could turn sharper to one direction.  To be fair, we are talking about an RC car from 34 years ago.  Despite that, I like ORV (the Frog chassis) very much though. I somehow ended up with 4.  The "space-frame" chassis was well ahead of its time, and I think its still a very good vintage basher chassis.  In fact, I wouldn't mind if Tamiya made an all-new chassis based on that ORV frame. 

[Stiff chassis and parts]  If parts are too soft like octopus legs, that won't work well.  If you are trying to turn left, but the arms bend instead of wheels.  Nothing is that extreme, but you get the point.  Mechanical designs work better when things are not bending where they are not supposed to. 

But I get what Saito2 is saying.  You don't want your steering wheel to be too precise.  What if your commuter car is so precise, you have to hold onto your steering wheel as if you are doing a brain surgery?  That would be nerve-wracking.  RC car could be the same.  Mere mortals like me can't react in 6 millisecond. (Good transmitters transmit every 0.006 second)  But if your car is so rigid and precise, you would also have to be so precise too, which is hard.  How stiff is good?  That's somewhat like tire-pressure.  You want your tires to be firm enough to be precise.  But you don't want to replace your tires with pizza cutters either (though that would be very-very-very precise).  My guess is that's why some RC10 folks like the aluminum tub.  If I'm racing, I might care to have the stiffest material.  Since I'm bashing, nylon arms are fine.  They break less.  

[Pillow balls]  This is not a big deal, but better ones have arm pivot pins rest on a set of spherical tubes.  In turn, those balls are held in place by the chassis.  It's like ball bearings for the pins, but even without these, good Teflon grease would work just fine.  You have no idea how many times those things rolled off my table.  

[Slipper Clutch]  The common wisdom says, "to protect the drive train."  But I think it's to soften the blow to the ground just a bit.  Too much RPM makes tires grip as much a dirt bike in watery mud.  It's like a gasoline engine in 2nd gear working better in snow than max RPM of a Tesla.    

"Better chassis" would allow you to adjust a lot of things.  But for novices (including a basher guy like myself), more adjustability could mean more trouble also.  A very cheap $30 RC car may be made out of very flexible material. Because they don't want children breaking things. Nothing is adjustable, etc.  But for the most part, Tamiya's entry-level cars are quite well made to last decades.  In my opinion, almost nothing in Tamiya is a "bad chassis."  Just simpler to minimize the headaches.  Of course, if you want to race, $800 TRF stuff could give you a "good chassis" also. 

While good and bad could be subjective, hopefully above could shed some light. 

 

[Jonathon Gillham]

I think there is an obvious advantage to a "bad" chassis which is they are a great excuse as to why you didn't win.

Its horses for courses though. My HB D817 is a great chassis at my club as it excels at low grip tracks, but Mugen make a better chassis for higher grip. My TA07 was awful indoors on carpet as its too flexible (and others run Awesomatix, TRF, Xray etc) but its much better on asphalt when the club runs outdoors.

The adjustability is great if you know what you're doing, but the TT02 class at my club is very popular as there is nothing to adjust so it appeals to a lot of people.

[Pablo68]

TRF shocks fix everything. EVERYTHING!

[Honza]

What's "good" and "bad" is something really subjective. It depends what you want, good racing chassis can be too fragile, which means bad for bashing, bashing chassis might be too heavy and slow for serious racing.

So really bad chassis is the one which just won't work for you from whatever reason. Really bad chassis is fragile, heavy, non reliable, non adjustable and without spare parts available.

[TwistedxSlayer]

Ifs it's Tamiya. It's good. If it's not... 😊😂😊🤣🤣