10th buggies needing weight. Poor design?

[s22jgs]

Bit of a random one here.
Having come from a nitro off road background the concept of adding weight was a new one to me at first.

I had a 22 and that needed so much weight and Ali parts to make it work.

I now run the Durango 210 and it's great without weight. I have tried a front weight and what I gained from the weight was no different from what I gained from pure setup.

Got me thinking, is the need for adding weight to some cars poor design on the manufacturers behalf, or a lazy way of achieving what can be done with some testing and setup time?

The 22 I could not make work purely with setup. The Durango I can make work by adding a small bit of weight or by simply changing the front end setup to get the steering I like.

No right or wrong answer, just interested in other peoples takes on the whole weight thing

[SlowOne]

It's a legacy from the NiCad/NiMh days. Cars were designed to work with a lot more weight than they have today, so the easy way to get things to work is to add weight back to the old levels so the designs we have work.

It's about getting enough weight on the tyres so they function effectively. Other classes have effectively dropped their weight limits to make the most use of the LiPo technology, but they have softer tyres to work with. It would be interesting to see how well the cars worked with tyre compounds that were a lot softer. However, I suspect that the cars wouldn't fly well or give any reasonable traction despite the softer tyres.

It isn't poor or lazy design by the manufacturers, it is that none of them have managed to find a design that works when you take a chunk of weight out of the car. Seems like we got it right all those years ago...

[s22jgs]

I find it odd that with today's technology in terms of design software, and simulation software capabilities that no one has yet produced a car that doesn't need additional weight.

I know that's a bit of a general statement, not everyone runs weight, and I myself prefer my 210 without weight.

It just seems as though adding weight wherever possible is a hot topic so to speak.

Totally understand the thing of tyres not having changed for 10th off road though.

Could it be that the newer cars just need to move to a softer compound. Maybe to something like ballistic pinks instead of schuey yellows?

[JohnM]

Originally Posted by SlowOne

It's a legacy from the NiCad/NiMh days. Cars were designed to work with a lot more weight than they have today, so the easy way to get things to work is to add weight back to the old levels so the designs we have work.

It's about getting enough weight on the tyres so they function effectively. Other classes have effectively dropped their weight limits to make the most use of the LiPo technology, but they have softer tyres to work with. It would be interesting to see how well the cars worked with tyre compounds that were a lot softer. However, I suspect that the cars wouldn't fly well or give any reasonable traction despite the softer tyres.

It isn't poor or lazy design by the manufacturers, it is that none of them have managed to find a design that works when you take a chunk of weight out of the car. Seems like we got it right all those years ago...

I don't think it's just because of the change from NiMh to LiPo cells, more to do with the power that LiPo/ brushless motors are putting out these days, you say we're adding weight back to the old levels, I used to run my XX4 at 1593grams, by adding weight, not taking it away.

We need the extra weight to hold the cars on the ground now

[DCM]

A few years ago it was a hangover from the old batteries but now it allows you to tweak the balance and hence the handling of the car.

[cornishboy176]

Thing is these days the esc's,receivers,servos (low profile) batteries are getting lighter and the cars aren't becoming heavier,it's easier to add weight than try and put your car on a diet,I am having the same problem with my 210,I have put weight at the front and rear

[James]

Its really hard to 'shift' weight so the realistic option is to add it to change bias which of course is a tuning aid and can improve handling. There's a fine line though as adding too much weight numbs handling, it can make a car arguably easier to drive masking real handling problems which may be better solved with changing geometry or damping.

[Hpi_guy]

The reason for adding weight as I see it is the manufacture can't make a car that suits everyone, for instance I like more steering and a bit or rear end slip in the corners but other people might not so it is difficult to make a car that suits everyone's driving style without adding weight, they also can't make a cr that is perfect on high grip surfaces such as carpet but also perfect on something like loose dirt, that's my view on it

[Hpi_guy]

I also see it as a quick way to change the handling of a car if the track conditions change due to something like rain without changing camber and oils

[Rick-J]

I find the whole weight thing a bit puzzling. I have just got a second hand B4 and am about to start racing off road again after a break of about 15 years. Things were different back then as you say but adding weight was a big no no. Now days we have more battery power than we know what to do with so adding weight is not such an issue but surely adding weight is a disadvantage it would effect speed and direction change. So why does every on e add weight to the B4 and other buggies?

[AdamBurgess]

Originally Posted by Rick-J

I find the whole weight thing a bit puzzling. I have just got a second hand B4 and am about to start racing off road again after a break of about 15 years. Things were different back then as you say but adding weight was a big no no. Now days we have more battery power than we know what to do with so adding weight is not such an issue but surely adding weight is a disadvantage it would effect speed and direction change. So why does every on e add weight to the B4 and other buggies?

As mentioned, its all about balance really. Alot of cars these days have gone mid-motor to optimise weight distribution to suit the high grip tracks we run on in this country so when it comes to running some thing a bit old school like the B4 you find adding weight to front helps the balance and gives you half a chance of keeping up with the mid-motor cars. The B4 was designed when we were using heavier electronics/batteries so now with the lighter Lipo's and slimline servo's the weight bias has moved rearward. Thats why people either add brass front bulk heads and weights under the servo and/or Lipo to their B4's, to bring the weight balance forward again allowing the car to work as it was designed. Or they just do the C4.1 conversion bringing the motor forward.

[Si Coe]

You've also got to consider that not all electrics are equal. For example, my 210 runs without an underservo weight, because I'm using a fairly heavy DS1015 servo anyway. Other people using light low profile servos need that weight just to get the same balance as me.
Weight differences between Lipo's especially is quite significant, so you are always going to need some adjustment.

Incidentally many real life racing cars are made underweight and then ballast is added. It lets you tune the weight balance (as mentioned) and you can add and remove ballast until you are exactly on the limit.

In 2wd RC's though its more down to the fact that the balance of a good fast, jumpy dirt track car is very different from that of a tight grippy astro car, so all designs, even convertible ones like the 22 and 210 are naturally a compromise.

[flipside]

Originally Posted by s22jgs

I find it odd that with today's technology in terms of design software, and simulation software capabilities that no one has yet produced a car that doesn't need additional weight.

That would be an X6... No weight on astro, and a bit of weight in the rear for dirt.