Infraction 1/7 scale road racing thread. (T/C,G/T, F1, and Indy)

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My ultra light 4S 1/8 Serpent GT-E on it's original tires will beat any 1/7 on a (medium sized) road circuit.

Weight is the biggest enemy. Drifting and powerslides looks cool but they are slow. It's all about perfect racing lines, being in control all the time. Not saying aero isn't important, but that's finetuning... Use a centerdiff and don't go to heavy on diff oil weight.

These 'medium' compound Serpent tires are much softer and grippier than GRP S1's and won't like 100+mph speeds, but they will corner like crazy. https://www.serpent.com/xcart/cart.php?target=product&product_id=10546

Great to know.
Have you by chance ever tried the V1 Hobao VTE original tires? I had seen them in a hobby shop years ago and they seemed very soft/grippy. I expect they wont go above 70mph safely.

1649859049910.png
 
Great to know.
Have you by chance ever tried the V1 Hobao VTE original tires? I had seen them in a hobby shop years ago and they seemed very soft/grippy. I expect they wont go above 70mph safely.

View attachment 211702
The VTE1 tires are not belted and have two horizontal threads where it will pizzacut in between. ~40mph is enough to ruin the body.

As for softness they are simular to those serpent mediums(which are belted)
 
The VTE1 tires are not belted and have two horizontal threads where it will pizzacut in between. ~40mph is enough to ruin the body.

As for softness they are simular to those serpent mediums(which are belted)
Sounds like the Serpent wheels/tires are the way to go.
I wish the Serpent GT e was not so expensive that is a very nice car.
 
I bought the GT-E as a raceroller, that's not too expensive (cheaper than a limitless roller)

Because it was so fine out of the box, i kept it original, not allowing myself to mod it (other than adding the electronics) Keeping the restriction of a 4068 motor is challenging for someone who likes speedrunning ;)

Not much later i bought the hobao VTE v1 roller(allowing a bigger motor) so i did have something to mod and that one really needed it. Out of the box experience there wasn't that great, like the tires mentioned above, but also the body and battery placement where horrible. They have done a much better job with the VTE2...


<edit> for reference, the GT-E is 3.5kg w/o batteries whiles my 'low weight' VTE2 is 4.6kg w/o batteries.
The longer wheelbase of a 1/7 is only really usefull for speed, not for cornering.

<edit2> the real soft tires are actually sweep 45e slicks, i forgot i had swapped out the serpent original tires after i blew one. They are still soft, but pretty close to the grp S1 (still grippier)
 
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I bought the GT-E as a raceroller, that's not too expensive (cheaper than a limitless roller)

Because it was so fine out of the box, i kept it original, not allowing myself to mod it (other than adding the electronics) Keeping the restriction of a 4068 motor is challenging for someone who likes speedrunning ;)

Not much later i bought the hobao VTE v1 roller(allowing a bigger motor) so i did have something to mod and that one really needed it. Out of the box experience there wasn't that great, like the tires mentioned above, but also the body and battery placement where horrible. They have done a much better job with the VTE2...


<edit> for reference, the GT-E is 3.5kg w/o batteries whiles my 'low weight' VTE2 is 4.6kg w/o batteries.
The longer wheelbase of a 1/7 is only really usefull for speed, not for cornering.

Yeah the VTE 2 is honestly the best RC car I have owned so far. I really like it.
I fully expect a Serpent or X-Ray would be considerably better, but the VTE 2 works well for me.

I am on the fence about a parking lot car as I doubt I would actually use it unless there was a group of Locals that I could run with. I am already thinking about selling my Kraton 6s because only the 10 month old baby likes to play with it at this point. I cannot keep him away from it in the garage. He likes to push it around or sit on it :LOL:

For me an RC car that does not get used is just wasted space and money.
 
For me I like driving around some kind of track. I don't mind that I'm the car park by myself. Even with my Kraton, i enjoy puttung in laps around a BMX track more than just driving around.

That's just me. I like a path to follow 🥸

The infraction seems like a good fun car park racer, and powerful drift machine, and high speed demon, all in one.

Chuck on GRPs for some carving action, then a quick swap to silver hoons for a pack of powerskiding fun, all with the same car.

The infraction will not be a competitive track racer, but that's what i expect or want it to be.

I am planning on removing the second un-used battery tray, and cutting off the un-used receiver box plastic (my receiver is on the other side), as its all material not needed.

That'll be enough weight saving, along with running a single 4S battery. I'll weigh it when I'm done.
 
It is funny how many times I recommend GRPs and people often come back saying.... No I am ok with Hoons :LOL:
GRPs are really good and the new series are so much better than last years model. So glad they fixed the tire and wheel balance issues.

Am looking to get some GRp tires for my lim; I see on they are offered on "flex wheels" or "rigid wheels"; I'd be running on lots that would have occasional stone and running speeds of 55mph or less typically. I imagine I should go for the flexible wheels, any idea if there are different rigidity between the wheel colors black, grey, yellow ect?

for compound I'd probably go with medium hard.
 
Am looking to get some GRp tires for my lim; I see on they are offered on "flex wheels" or "rigid wheels"; I'd be running on lots that would have occasional stone and running speeds of 55mph or less typically. I imagine I should go for the flexible wheels, any idea if there are different rigidity between the wheel colors black, grey, yellow ect?

for compound I'd probably go with medium hard.
I don't think the rigid wheel is necessary unless you want to go over 100mph or doing some competition level racing.
From what I understand all are flex wheels except the white rigid wheel.
 
I had my first run with the GRP slicks S7 (medium hard compound) and the first thing I'll say, is if you want grip, get GRP's and don't worry about Hoons anymore.

These hard compound GRPs have way more grip than the white HOONS. Not just a little more...way more!

I can't imagine how well the soft GRP's would grip like.

So I'm going to stick with GRP's from now on for my car park racing.

I am still intending to get a set of the solid rubber slip on's that WestOz RC has been testing, for when I just feel like drifting around and having fun that way...without breaking the bank on HOONS.
which ones specifically? am checking out now and only hard-medium compound I see is for slicks is GTK04-XM7.

Am not sure the difference between XB and XM compound; any ideas? I find their descriptions confusing.

GTX04-XM7 - medium-hard - "Very high grip for clean track / medium asphalt / very high temps"

GTX04-XM3 - Soft - "Medium Grip for clean track / medium asphalt / medium temps"

GTX04-XB3 - Soft - "Medium grip for "fine" dirt / asphalt / low temps"
 
I've finished with the reconfiguration to better suit using a single battery.

The running weight of the car is now approx 1kg lighter. 600 grams of that is one less battery, and the rest is unnecessary stuff I removed.

Took the car for a proper run today and it's fast in 4S, but I did the Hobbywing Max 6 swap at the same time so I can't say how much is the weight reduction.

Either way, Less weight is better, so these changes seem like a good step for circuit style driving.

6CFF76F6-B984-42CF-8F00-70D5C0E7F9B3.jpeg

The fan mount is temporary. I'll do something better in the next few weeks.

I'm intending on replacing those 35mm fans with 40 mm or 50mm fans.

BTW i weighed all the parts and arranged them that way to balance weight on the left and right sides.

Don't know about forward/a weight balance. It seemed to handle good still.
 
I've finished with the reconfiguration to better suit using a single battery.

The running weight of the car is now approx 1kg lighter. 600 grams of that is one less battery, and the rest is unnecessary stuff I removed.

Took the car for a proper run today and it's fast in 4S, but I did the Hobbywing Max 6 swap at the same time so I can't say how much is the weight reduction.

Either way, Less weight is better, so these changes seem like a good step for circuit style driving.

View attachment 212624
The fan mount is temporary. I'll do something better in the next few weeks.

I'm intending on replacing those 35mm fans with 40 mm or 50mm fans.

BTW i weighed all the parts and arranged them that way to balance weight on the left and right sides.

Don't know about forward/a weight balance. It seemed to handle good still.
Are you sure about the left/right balance? ESC+ bulky 4S battery seems heavier than a motor(close to center) and a servo.

Between 50/50 and 60F/40R should be what you are looking for F/R weight balance
 
Are you sure about the left/right balance? ESC+ bulky 4S battery seems heavier than a motor(close to center) and a servo.

Between 50/50 and 60F/40R should be what you are looking for F/R weight balance
No, I'm definitely not sure its balanced😛

I'd really need one of those 4 pad weight gizmos to put under the wheels to do it properly. I am thinking of getting one, or maybe 4 cheap small kitchen scales?

That motor is fairly heavy. Its the Hobbywing 4985 (587g - 20.71oz) and there's also the esc/servo mounting plate too.

The overall weights per side were about 50grams different, but yes the distribution on each side won't be perfect.

But it still handles fine so isn't having a negative impact that I can see yet.

Thanks 👍
 
No, I'm definitely not sure its balanced😛

I'd really need one of those 4 pad weight gizmos to put under the wheels to do it properly. I am thinking of getting one, or maybe 4 cheap small kitchen scales?

That motor is fairly heavy. Its the Hobbywing 4985 (587g - 20.71oz) and there's also the esc/servo mounting plate too.

The overall weights per side were about 50grams different, but yes the distribution on each side won't be perfect.

But it still handles fine so isn't having a negative impact that I can see yet.

Thanks 👍
2 scales is sufficient.

It's not just weight, but weight x distance to center. 250g esc and 600g battery are further away from the center.
L/R balance is easy to see, by picking it up with 2 fingers, one front center , one rear center. if it doesn't tilt, it's fine.
 
Kitchen scales are very cheap, so I'll get some and post back the results. 👍

I'm interested to see the results for my other RCs as well, especialky my race Tekno truggy.

Cheers
 
Had my first real race track run today. It was a blast, even though the track was a little slippery due to light rain, but I tried out the GRP rain tyres and they worked ok.

AEAB0278-B4BB-4593-A7DF-A54270F74A77.jpeg


Had one minor crash after cutting across a curb too much and it flipped the car, luckily at low speed.
CA3B971C-36FD-4440-B9FA-E0C9E3CDC2F4.jpeg

Now I'm hooked big time!

I got some advice from someone there who raced 1/8 GT cars.

He suggested that to improve my infractions handling, I need to:

1- stiffen up the springs, and increase the oil weight. The front should be stiffer/heavier oil weight than the rear.

2 - lower the ride height to about 6mm.

FYI the stock springs are...

Front

ARA330600 | 35mm 4.7N/mm (27lb/in)​

Rear

ARA330599 | 40mm 6.6N/mm (38lb/in)​


Arrma does two stiffer front 35mm springs...

F46BB2EC-E15C-489D-8FAE-CCBEA832BC27.png


I'll probably get both to try out.

For the rear, I can't see any stiffer springs from Arrma. Do I just search for 40mm springs, maybe from Tekno or similar race brands?

What about oil weight suggestions? The manual shows the stock weight is 2000 on both ends, which seems high to me...
F423301A-0261-4AB2-8891-AA81C87CA7DA.png


So I thinking of trying 2500-3000 or thereabouts on the front, and 2000-2500 on the rear. Any suggestions, thoughts?

I've also got a good selection of different GRP compounds now, so starting to try them out in different situations to see what works.

Still have to do my weight balance measuring. I have the scales now.

Cheers!
 
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I'm struggling to find any shock fluid higher than 1000cst, let alone 2000 or higher.

rc-silicone-shock-oil-comparison-chart_orig.jpg


Is silicone shock and differential 'oil' the same thing? They look the same, but I know they could have some differences chemically.

What am I missing?
 
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Time to go to bed! Its late, but I think I've answered my question, that silicone diff and shock fluid, are essentially the same thing, and can be used in either, as long as its the viscosity you want.

So I can get 3000cst diff fluid, and use that to replace the stock 2000cst shock oil.

I'm still none the wiser about the rear springs though. But I'll change the front end first and see what that drives like, before I play with the back end.
 
Silicone oil is all the same, with exception of the weight, and can be used in either application, regardless of labeled intent.
 
One downside with these seemingly very high weight for the shocks, is that there's not many options. 2000, 2500, 3000, 5k7.5k 10k. There's not a lot of fine tuning like there is with' normal' weights under 1k.

A see how 3k goes, and I'll get a 2k s well of the same brand so i can mix them to get something in between.
 
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