Little Change, Big Difference

[Kowalski86]

I've been thinking about talks of "slop", tweaking, tuning, hop-ups, and what not. How much difference do some of these things really make out in the real world?

On one of my last truck projects I worked on swapping suspension arm mounts and a bulkhead brace. Up close, I liked the brace and improved mounts, but out in the real world in the dirt it didn't really make a difference.

On the other hand, I've found that suspension oil and springs make a noticeable difference even when you're just playing around. It doesn't matter if it's an on-roader or a monster truck, I've been surprised by how much springs effect an RC Car.

Then there's wheel weights, which I initially began experimenting with on M-chassis but they can make a big difference with crawlers and bashers too.

[Gebbly]

6 hours ago, Kowalski86 said:

wheel weights, which I initially began experimenting with on M-chassis but they can make a big difference with crawlers

I have read of people using wheel weights in crawlers before which made sense to me. It didnt occur to me to put them in anything else like an M car though. Wouldnt there be a trade off? Less likely to roll but reduced acceleration, top speed and worse breaking and cornering due to, well, the added weight?

Its an interesting topic you raise @Kowalski86, it would be good to see everyones experiences of the biggest "bang for buck" modifications so we can learn from each others experience.

[Mad Ax]

I've never heard of putting weights in m-chassis wheels before.  Crawlers yes, as keeping the wheel down against the terrain is important, but in a race car the bumps are going to throw the wheels upwards, and the suspension is going to have to work hard to bring them down again.  It could make it more likely to roll if you hit a kerb.  Unsprung weight is generally a bad thing in race cars, as far as I'm aware.  In fact I remember temporarily changing the wheels on my FTO to a much heavier wheel and the difference in braking, cornering and ride comfort was immediately noticeable, even just driving it carefully to the local tyre shop - I couldn't wait to get my proper ones back on again.

However I'm keen to learn and if there's something I've missed, please correct me  

[chris.alex]

Nice topic! What I learned among other things:

1. More care when adjusting the suspension, especially the dampers, makes a huge difference.

2. Save money when buying motors and spend more money when buying servos.

[Gebbly]

15 minutes ago, chris.alex said:

spend more money when buying servos

What makes a better servo? When I bought mine I went for metal gear and waterproof, are there other factors to look for?

[Twinfan]

18 minutes ago, Gebbly said:

What makes a better servo? When I bought mine I went for metal gear and waterproof, are there other factors to look for?

Kg rating and speed...

[Kowalski86]

3 hours ago, Gebbly said:

I have read of people using wheel weights in crawlers before which made sense to me. It didnt occur to me to put them in anything else like an M car though. Wouldnt there be a trade off?

There would be some noticeable trade offs if you went overboard, I mostly added weight to the side of my M05s to cover the pinion holes and compensate for its imperfect left/right balance.

On cralwers I might add one or two to the front, but I've found that heavy crawlers don't always perform better.

 

2 hours ago, chris.alex said:

Nice topic!

2. Save money when buying motors and spend more money when buying servos.

Thank you.

My suggestion will always be to save money by buying a good servo, instead of buying aluminum steering, upgraded servo saver, servo mount, then buying an off brand servo off of Amazon.

[Kowalski86]

2 hours ago, Mad Ax said:

I've never heard of putting weights in m-chassis wheels before.

When there's a minimum weight rule, some people tuck them into the front bumpers. I had an ex-asphalt raced M05 arrive like that.

I would usually just add one near the pinion holes to offset the weight of the motor sticking out on the M05 V1 chassis, nothing significant. I try to keep everything light myself.

[BuggyDad]

1 hour ago, Twinfan said:

Kg rating and speed...

And the believability thereof.

But yeah, I'm no racer but I was surprised by the driving improvement of a better servo and then again switching back and forth between my basic and better transmitter makes a real difference too (but I can't explain why and it's not exactly cheap!). 

My "small change, big difference" though is X-rings, grease and good pistons in CVAs. In my view, good fitting pistons and minimum friction seals makes a good shock and so this fairly inexpensive tinkering can make a big improvement to CVAs. They're no Big Bores but the CVAs on my Super Falcon are as good as the aluminium shocks on my DT-03. 

P.S. Great idea for a thread! 

[Mad Ax]

24 minutes ago, Kowalski86 said:

When there's a minimum weight rule, some people tuck them into the front bumpers. I had an ex-asphalt raced M05 arrive like that.

Aah, sorry, I misunderstood!  I read "wheel weights" as "weights in the wheels" - which I think would be a bad move on any fast-moving vehicle.  Although weights in the wheels of your crawler makes a massive difference, I usually add around 60g around my 1.9 rigs (4x 10g and 4x 5g around the middle), and they usually have aluminium wheels to which are a good deal heavier already than plastic wheels.

But yes - I have ballast in my M03 race car.  A little bit at the front and a couple of additional weights in the rear to help keep it planted.  It seems to be a matter of choice, some racers have quite a lot of weight and some have none.  I may experiment with removing some weight this weekend, now that I've changed the location of my ESC.

[markbt73]

It has been my experience that 90% of the tuning of these things is down to picking the right tires. And if you're at a race track, the easiest way to find them is to see what the fast drivers are using and do the same. It's a night-and-day difference, even with an otherwise stock entry-level car. And it makes sense: if you don't have traction, the suspension and steering and drivetrain can't do their job, so any improvements there are pointless without good tires. So I would say if you're going to spend money anywhere, spend it on tires first.

[Mad Ax]

1 hour ago, markbt73 said:

It has been my experience that 90% of the tuning of these things is down to picking the right tires. And if you're at a race track, the easiest way to find them is to see what the fast drivers are using and do the same. It's a night-and-day difference

I would absolutely second this - if you have the wrong tyres, you're fighting a losing battle.  I've had several very bad days on track when I haven't had the right tyres.

That said, another M-chassis racer compiled a basic setup spreadsheet for the last round of the Iconic Cup, where entrants could specify the chassis, tyres, ESC, radio and servo they were using, and it was surprising just how much variation there was in tyres - especially for M-chassis, which are so sensitive to grip roll when there's too much front grip and oversteer when there's too little rear grip.  The favoured tyre was Volante 30F/24R, but some ran Sweep EXPs 32F/24R, someone was running Sweep D-spec tyres, I think there was a 36F somewhere, and someone even managed to do the A-final with 24F/24R, which seemed crazy to me - perhaps there was a lot of superglue involved..?

[Kowalski86]

3 hours ago, Mad Ax said:

Aah, sorry, I misunderstood!  I read "wheel weights" as "weights in the wheels" - which I think would be a bad move on any fast-moving vehicle. 

No problem, even on crawlers I'm not quite sold on weighted wheels, but I've never really dumped money into one or tried competitive crawling.

[Pylon80]

6 hours ago, Gebbly said:

What makes a better servo? When I bought mine I went for metal gear and waterproof, are there other factors to look for?

The cars 'we' typically run do not need particularly high torque nor high speed; in fact back in the eighties and early nineties everybody was running standard, nylon gear, 3kg/cm torque and a slow .20sec/60 deg so called "standard" servos. It was working and people were driving fast and developing skills and enjoying themselves.

Today we are benefitting from the digital servo revolution when servos can hold their position better and more importantly recenter properly. So when you exit a corner the car did not 'memorize' the last steering input but rather leaps nice and straight. This is the most important factor in my opinion, and you guessed it... one that does not show in the specs! I have had success with branded servos (except one entry level Savox) and not much success with cheaper servos (SPT and Trackstar to name these few). Then there are popular higher end servos that I did not like (Savox...) since the gears were notchy and noisy and it was jittery regardless of the BEC I used and even with an external capacitor.

These days I use the servos from the Hitec D series which now uses 25t splines like everyone else. It's too bad they don't have a low profile! For cars that must use a low profile I still have some older (discontinued) Futaba ones.

6 hours ago, chris.alex said:

2. Save money when buying motors and spend more money when buying servos.

@chris.alex is right on.

[No Slack]

I discovered that the way you build your shocks also makes a difference. Old news for many but for me new. I always followed Tamiya with their instructions of filling the shocks with oil but... YouTube showed several movies that there are other ways. The piston low when filling or halfway or high. Magic.

[Juls1]

With touring cars and off road buggys that have adjustable camber, a setup station that allows you to get left to right precisely identical suspension settings. This is a game changer in getting a neutral handling vehicle that feels the same and predictable regardless of direction you turn. Don’t assume having equal measured links means your car has equal left to right camber. 

[Kpowell911]

On 6/26/2024 at 10:13 AM, Gebbly said:

What makes a better servo? When I bought mine I went for metal gear and waterproof, are there other factors to look for?

Speed is the main one. I honestly cant believe the real world difference between a great servo and] a cheap one. Its night and day. I cringe everytime someone posts something positive about the Amazon 25-35kg servos! They’re awful I dont care how cheap 

[Andreas W]

6 hours ago, Juls1 said:

With touring cars and off road buggys that have adjustable camber, a setup station that allows you to get left to right precisely identical suspension settings. This is a game changer in getting a neutral handling vehicle that feels the same and predictable regardless of direction you turn. Don’t assume having equal measured links means your car has equal left to right camber. 

This. Getting a second hand setup station was a gamechanger for me. Both the Carten M210R but first and foremost the M-08 improved drastical after both sides were equal.

[rich_f]

On 6/26/2024 at 3:25 PM, Mad Ax said:

I would absolutely second this - if you have the wrong tyres, you're fighting a losing battle.  I've had several very bad days on track when I haven't had the right tyres.

I agree and it's the reason I lost interest in racing. I can't afford to have umpteen different sets of tyres for the particular track and the conditions at the time.

I started racing on polished wood floor, then indoor on carpet (both of which only required a single tyre type to be competitive) then outdoor on tarmac tracks with a single control tyre. I had a few years off then started racing in the iconic cup but since tyres are open, you really need a selection of compounds, otherwise you've only really got the best-suited tyres for one part of the day, if that.

(having said that, I haven't looked at the iconic rules for a few years so I'm not sure if the tyres are all still open)

[Mad Ax]

2 hours ago, rich_f said:

I agree and it's the reason I lost interest in racing. I can't afford to have umpteen different sets of tyres for the particular track and the conditions at the time.

It's a valid point - and also getting through them so quickly.  I got through 2.5 sets of front tyres at the Iconic Cup this weekend.

[Kowalski86]

On 7/1/2024 at 10:40 AM, rich_f said:

I agree and it's the reason I lost interest in racing. I can't afford to have umpteen different sets of tyres for the particular track and the conditions at the time.

For me, the simple fact is that it wouldn't cost much more to race "real cars" in a budget class (chump cars, lemons). Its a bit easier finding parts for some 1:1 cars than dated race buggies.