Infraction anyone changed the gear ratio to run felony wides on rear?

[MidKnight]

im wanting to run the wide dboots on the rear of the infraction, and to do so, from arrma site below.

anyone done this and knows if the handling is still good or not?

Requires:​

To use 107mm diameter tires on the rear axle of your vehicle and 100mm diameter tires on the front axle you must change the ratio of the gearboxes to account for the different rollout values. To do this use GP5 gears in the front gearbox and GP6 gears in the rear gearbox:


FRONT:


ARA311016 - MAIN INPUT GEAR 15T GP5


ARA311017 - MAIN DIFF GEAR 42T GP5


REAR:


ARA311018 - MAIN INPUT GEAR 14T GP6


ARA311019 - MAIN DIFF GEAR 45T GP6

 

[Boggs3010]

Lmao just changed my felony to gp5 in the rear. Minutes ago no less. I don't like the handling in the felony never have, tried lots of changes to try and counter it. Gave up and changed the gearing.

 

[MidKnight]

oh fair enough. looks heaps better with the fats on the rear though

 

[Boggs3010]

Try it don't like it change it back. You may like the drifting.

 

[MidKnight]

do you have the infraction, or only the felony?

 

[SrC]

Lmao just changed my felony to gp5 in the rear. Minutes ago no less. I don't like the handling in the felony never have, tried lots of changes to try and counter it. Gave up and changed the gearing.

I agree that most go with the stock Infr setup on the Fel. 42/100's. Not the other way around.
The looks of fatter rear wheels will entice you , just that I feel the larger 53/107 Hoons aren't all that in general. Won't hook up. the Felony is a showboater. Body and fatter rear end. Nice looking on the shelf., just harder to drive.
And I am sure I will be flamed for this.
I have run 4 of the 53/107s on a custom LWB build. Traction isn't all that. And that is using 4 of them.
You are left with little to no choices in other brand tires and compounds. Pretty much stuck using these on the rear of an Infr. Like the Fel.
Arrma should have increased the tire width only, and not the hight/rollout. And made a 53/100 tire instead. While keeping the Rear diff ratio the same as the front. My spin.

 

[Boggs3010]

do you have the infraction, or only the felony?

3 infractions 2 Felony's

 

[SrC]

oh fair enough. looks heaps better with the fats on the rear though

Yeah looks better, while on the shelf.
Driving it, will it really look better, from a distance while you struggle to drive it?
I have a Lim and Infr., I passed on the Fel. specifically because of this.
Many have sold their Fel, out of frustration. Rather run their Infr and Lims by comparison.
Stay with the stocker F/R ratio setup with your Infr.

 

[parcou]

^^^^^ yep!

 

[Diem Turner]

Can someone explain this to me, because mathematically those diff ratios in the Felony do not make sense to me. To illustrate this, I calculated a 4S lipo with 28/34 gearing and 1320KV (which is a 1650 under load). The front diff has a 2.8 ratio and the rear 3.21. The front wheels have a diameter of 100mm (3.93") and the rears 107mm (4.21"). The top picture is Vmax front wheels, the bottom Vmax rear wheels. What am I missing? I'm getting a speed differential of nearly 7km/h. Is it that the rear tires balloon a little bit more than the fronts because they're wider? If that were the case, that sure would go a long way to explaining the above mentioned catastrophic handling of the Felony because the wheel speed delta F/R would be all over the shop across the rev spectrum (i.e. at slower speed the front would be dragging the rears across the tarmac and then, when you gun it, the speed of the rears suddenly matching or overtaking the fronts). Am I understanding all this correctly?

 

[LibertyMKiii]

Just as an FYI the power hobby gripper tires offer 100mm diameter front and rear but give you the wide rear tire. This saves you the cost of swapping diffs and if you dislike the handling it would be easy to swap back to regular tires.

 

[Diem Turner]

Just as an FYI the power hobby gripper tires offer 100mm diameter front and rear but give you the wide rear tire. This saves you the cost of swapping diffs and if you dislike the handling it would be easy to swap back to regular tires.

View attachment 218522

I actually have a set of those on the way

 

[Diem Turner]

The reason I was asking is because the 917K body looks better when you have larger diameter wheels in the back so I was thinking about running GRPs or Contacts up front and Pro-line Avengers in back. I have a 45T gear on the way that I'm going to try out on the rear diff. Mathematically that gives me speed delta of only 0.02km/h front to rear, so we'll see how that goes.

 

[SrC]

May look nice on the shelf, just that Speed Runners will never use the 53/107 Hoons or their aftermarket equivalents.
I have a set of them for tooling around. TLRT etc. I find that traction is horrible with this size tire. Not a good match for the smaller front 42/100's. Traction bias will take a hit for the worse IMHO. Many have traction issues with their Fel's because of this.
Drivetrain and handling performance appears to be best running identical 42/100 Hoons or equivalents (GRP's) all around. (Infraction setup)
Just me.

 

[Diem Turner]

May look nice on the shelf, just that Speed Runners will never use the 53/107 Hoons or their aftermarket equivalents.
I have a set of them for tooling around. TLRT etc. I find that traction is horrible with this size tire. Not a good match for the smaller front 42/100's. Traction bias will take a hit for the worse IMHO. Many have traction issues with their Fel's because of this.
Drivetrain and handling performance appears to be best running identical 42/100 Hoons or equivalents (GRP's) all around. (Infraction setup)
Just me.

I don't think it's just you ;-)
What you're saying, and correct me if I'm getting something wrong, seems to echo what I was describing above though, so far, no one has actually addressed the questions and hypothesis I submitted attempting to address what might actually be the root cause of the poor handling characteristics of the Felony. I can't help but wonder if you had diff ratios in the Felony that produced equal wheel speeds front and rear, whether that would possibly sort out the traction problems people report.

Just to be clear, I'm neither advocating for nor trying to make the case for using 107mm wheels for speed running. I'm just trying to figure out how I can get a car with the 917 body on it to look and handle as good as possible.

 

[joshjosh]

Calculating the speeds using the factory gearing there's over a 7 MPH variance between the front and rear tires. The gearing can easily be corrected to allow the Felony to run a center spool and potentially a rear locker for bashing. This cheap and easy mod will make the car handle better, while helping tire and differential wear. Please check out my video for more!
To fix the gearing, just swap the front input gear out with this - GP6
Thank you!

Felony Gearing Fix

 

[Diem Turner]

Calculating the speeds using the factory gearing there's over a 7 MPH variance between the front and rear tires. The gearing can easily be corrected to allow the Felony to run a center spool and potentially a rear locker for bashing. This cheap and easy mod will make the car handle better, while helping tire and differential wear. Please check out my video for more!
To fix the gearing, just swap the front input gear out with this - GP6
Thank you!

Felony Gearing Fix

I'm not discounting that a spool helps mitigate the inherent handling issues of the Felony that comes with the 7mph wheel speed delta. What I would add, however, is that the problem is even worse than this. Because the front and rear tires are of a different width, the front and rear tires are bound to balloon at different rates. As if the wheel speed difference front/rear wasn't bad enough, the delta is undergoing constant fluctuation as the wheels transition from slow to fast and back again. The only other variant I would offer up is that, alternately, you could put GP5 ring and pinion gears in the rear which would give you the same gearing as an Infraction V2.

 

[joshjosh]

Thanks for commenting!

I'm not discounting that a spool helps mitigate the inherent handling issues of the Felony that comes with the 7mph wheel speed delta.

A spool would not help the speed issues between the front and the rear. In fact, it would make it worse! Without fixing the gearing first, the different sized tires spin at different speeds. The center spool would not allow the tires to spin at different speeds, so the difference in speeds will be seen as drivetrain and tire wear. Potentially even erratic driving behavior.

What I would add, however, is that the problem is even worse than this. Because the front and rear tires are of a different width, the front and rear tires are bound to balloon at different rates. As if the wheel speed difference front/rear wasn't bad enough, the delta is undergoing constant fluctuation as the wheels transition from slow to fast and back again.

After you perform the fix shown in the video, then really it shouldn’t be a big deal, even at high speed. I do touch on your point about tire ballooning in video as well, but honestly, these belted Hoons tires don’t balloon much.

The only other variant I would offer up is that, alternately, you could put GP5 ring and pinion gears in the rear which would give you the same gearing as an Infraction V2.

If you do this, then you must run the same sized tires. If your goal is to run the same sized tires, then you can just swap the front GP5 with the rear GP6 input gear. Similar goal without buying anything.