Alfa OBD or Jscan. Which is better?

[jmrhodes212]

As Jimmy07 said before, the process for making changes is the same between alfaObd and j-scan as they both interface with the BCM is the same way, and you have to change each setting individually

I don’t believe the steps or process in the software are the same. Just like he mentioned with checking codes, JScan does it differently and easier that AlfaOBD. I'm asking if JScan requires any extra steps in it's software beyond changing the tire size.

When you used JScan to change yours, what steps did you follow?

 

[Jimmy07]

I don’t believe the steps or process in the software are the same. Just like he mentioned with checking codes, JScan does it differently and easier that AlfaOBD. I'm asking if JScan requires any extra steps in it's software beyond changing the tire size.

When you used JScan to change yours, what steps did you follow?

Change the tire size like normal. If there are error messages or faults afterwards, run the abs initialization routine just like you would with AlfaOBD.

 

[mike_ct]

Do you have to do any of the "multiple steps" with Jscan that are required for alfaOBD to change the tire size? With Alfa there seems to be some steps beyond to reset the ABS, etc. Wondering if Jscan is just put in the number and save.

Thanks,

on j-scan, you just go into the tire size adaption, and select the size from drop down, and its done.

 

[jmrhodes212]

on j-scan, you just go into the tire size adaption, and select the size from drop down, and its done.

I have heard it's that easy. Hoping so.

 

[1BADRAMLIMITED]

They look like apples and oranges so it's hard to compare. It looks like JScan is more for sensor monitoring (like my Torque Pro app does) and AlfaOBD is settings modifications.

I'm not familiar with JScan and the website does not reveal a lot of information:

- How much is a license?
- What is "vehicle adaptations"?

It does not say you need a Security Gateway bypass so don't know if you can change any settings.

I know RAM is part of the Chrylser/FCA/Stellantis family but the webite only shows Jeep and van (Caravan and T&C) compatibility.

If I wanted to read live data I'd give it a shot for free but I don't know if it will do what AlfaOBD will.

AlfaOBD is going to cost you (~$50) in addition to the SGW bypass and OBDII connection (which you need for JScan anyway).

Again, I have no experience with JScan (or if it works on our RAMs).

whats the difference between alfaOBD and Tazer?

 

[HSKR R/T]

whats the difference between alfaOBD and Tazer?

Two completely different things. TazerDT isa plug in module that you control umthrough the EVIC screen using steering wheel controls. Has a predefined menu that allows you to change certain things and also offers "live" features only the TazerDT can do.

alfaObd is an app you install on your phone/tablet/laptop that interfaces through an OBD2 adapter. It allows you to enable or disable certain features, most of which are just factory options.

 

[THFD334]

I just updated the tires size using jscan. Wow! Quick and easy. Didn’t have to figure the circumference or anything. Just pick from the drop down size. (35’s for me). I did have to do the abs initialization but that was easy as well. Tested it with Waze gps and cruise control set, spot on. My own opinion, depending on what you’re wanting to do, jscan was way easier than AlfaOBD.

 

[mike_ct]

I just updated the tires size using jscan. Wow! Quick and easy. Didn’t have to figure the circumference or anything. Just pick from the drop down size. (35’s for me). I did have to do the abs initialization but that was easy as well. Tested it with Waze gps and cruise control set, spot on. My own opinion, depending on what you’re wanting to do, jscan was way easier than AlfaOBD.

did it mess up your park sensors? if I go over 33, my sensors stop working

 

[Rampat]

did it mess up your park sensors? if I go over 33, my sensors stop working

Yes. It’s a Ram thing. Nothing you can do, all devices will trigger that when you go above a certain size. I have mine set at 34.5 and they’re gone, but I always disabled them with the switches anyway because I hate beeps.

 

[HSKR R/T]

Yes. It’s a Ram thing. Nothing you can do, all devices will trigger that when you go above a certain size. I have mine set at 34.5 and they’re gone, but I always disabled them with the switches anyway because I hate beeps.

My 2020 is over 34.5 and park sensors work just fine

 

[Jimmy07]

My 2020 is over 34.5 and park sensors work just fine

I’m finding out that, depending on which device is used, and even AlfaOBD, the tire diameters in inches they assign to circumferences in mm vary widely, and don’t work out mathematically.
The only true number that matters is what the BCM sees as the circumference in mm in VehConfig 4:

So, a rough example would be- even though that 2511 circumference translates to 31.5” tire, they might have it labeled as a 33” tire in the quick pick list for tire sizes.
It seems that somewhere after 2700mm in that VehConfig 4 setting is when the park assist trips up, so even though whatever device you used to change the tire size called out 34.5”, that setting may actually be lower than 27xx mm in VehConfig 4 when you read the BCM system ID.
I’ve been meaning to start a data collection thread on this where people report what that VehConfig 4 setting is actually set to, and if park assist errors out for them or not.

 

[HSKR R/T]

I’m finding out that, depending on which device is used, and even AlfaOBD, the tire diameters in inches they assign to circumferences in mm vary widely, and don’t work out mathematically.
The only true number that matters is what the BCM sees as the circumference in mm in VehConfig 4:
View attachment 158392
So, a rough example would be- even though that 2511 circumference translates to 31.5” tire, they might have it labeled as a 33” tire in the quick pick list for tire sizes.
It seems that somewhere after 2700mm in that VehConfig 4 setting is when the park assist trips up, so even though whatever device you used to change the tire size called out 34.5”, that setting may actually be lower than 27xx mm in VehConfig 4 when you read the BCM system ID.
I’ve been meaning to start a data collection thread on this where people report what that VehConfig 4 setting is actually set to, and if park assist errors out for them or not.

I can send you mine when I get home if I remember. I used my TazerDT to change the size

 

[HSKR R/T]

I’m finding out that, depending on which device is used, and even AlfaOBD, the tire diameters in inches they assign to circumferences in mm vary widely, and don’t work out mathematically.
The only true number that matters is what the BCM sees as the circumference in mm in VehConfig 4:
View attachment 158392
So, a rough example would be- even though that 2511 circumference translates to 31.5” tire, they might have it labeled as a 33” tire in the quick pick list for tire sizes.
It seems that somewhere after 2700mm in that VehConfig 4 setting is when the park assist trips up, so even though whatever device you used to change the tire size called out 34.5”, that setting may actually be lower than 27xx mm in VehConfig 4 when you read the BCM system ID.
I’ve been meaning to start a data collection thread on this where people report what that VehConfig 4 setting is actually set to, and if park assist errors out for them or not.

So not sure what the TazerDT actually changes in the vehicle config files. You can see where it's set, and allows speedometer to be accurate. And I highlighted my current config file from alfaObd to show tire circumference. Which obviously isn't effecting the speedo being wrong.

 

[Jimmy07]

So not sure what the TazerDT actually changes in the vehicle config files. You can see where it's set, and allows speedometer to be accurate. And I highlighted my current config file from alfaObd to show tire circumference. Which obviously isn't effecting the speedo being wrong. View attachment 158442View attachment 158443

Yup, just as I suspected. That’s definitely the number tazer changed in the configuration (and what ALL tire size programming devices change). I’ll have to rifle through some saved configs, but if I remember right, a BTS edition is usually set to 2532 from factory (for reference, a TRX is set to 2680).

 

[HSKR R/T]

Yup, just as I suspected. That’s definitely the number tazer changed in the configuration (and what ALL tire size programming devices change). I’ll have to rifle through some saved configs, but if I remember right, a BTS edition is usually set to 2532 from factory (for reference, a TRX is set to 2680).

Just wondering how the listed circumference translates to a 34.69" diameter. Cause the math sure as hell doesn't work. And I'm running 35x12.50x20 tires. Speedometer is correct. Yet many people claim they had to enter larger number, in alfaOBD, to get speedo correct, for the same size tires, or some even smaller

 

[Jimmy07]

Just wondering how the listed circumference translates to a 34.69" diameter. Cause the math sure as hell doesn't work. And I'm running 35x12.50x20 tires. Speedometer is correct. Yet many people claim they had to enter larger number, in alfaOBD, to get speedo correct, for the same size tires, or some even smaller

There’s way too many variables when it comes to tire size and speed. That’s why you get different numbers from people that can be running the exact same tires.

While the circumference that the BCM reports is static, tire circumference is dynamic. It changes based on tire pressure, tire tread wear, and centrifugal forces applied at different speeds.

Then you have the fact that the actual diameter of a tire is usually a little smaller than the manufacturer claims, compounded by the fact that the exact same model numbers of tires vary in size among themselves. THEN, throw in GPS speed variances and different GPS apps that people use, and you can literally be +/-100mm in what people report which circumference number works for them while using the exact same tire as others. And that’s why whenever someone asks what size to set their tires to in order to correct the speedometer, only that person can determine that, and all responses are pretty much irrelevant, or at most just a general baseline.

 

[HSKR R/T]

There’s way too many variables when it comes to tire size and speed. That’s why you get different numbers from people that can be running the exact same tires.

While the circumference that the BCM reports is static, tire circumference is dynamic. It changes based on tire pressure, tire tread wear, and centrifugal forces applied at different speeds.

Then you have the fact that the actual diameter of a tire is usually a little smaller than the manufacturer claims, compounded by the fact that the exact same model numbers of tires vary in size among themselves. THEN, throw in GPS speed variances and different GPS apps that people use, and you can literally be +/-100mm in what people report which circumference number works for them while using the exact same tire as others. And that’s why whenever someone asks what size to set their tires to in order to correct the speedometer, only that person can determine that, and all responses are pretty much irrelevant, or at most just a general baseline.

I get all that, but if you do the math for the circumference shown in config file, it works out to somewhere in 33" range. While I know a 35x12.50 tire isn't actually 35", I also know it's not 33". And I have checked speedo with multiple GPS apps, and the radar road signs.

 

[Jimmy07]

I get all that, but if you do the math for the circumference shown in config file, it works out to somewhere in 33" range. While I know a 35x12.50 tire isn't actually 35", I also know it's not 33". And I have checked speedo with multiple GPS apps, and the radar road signs.

For the actual rolling circumference, you don’t use the total height of the tire as it sits, and definitely not its diameter when it’s not mounted. You take the height from the ground to the center of the wheel hub x 2 x 3.14 x 25.4.

So, you got a 35” tire. MAYBE it’s actually 34.5” when not mounted. Then you mount it, air it up, and put the truck weight on it.
You’re set at 2654mm, which is 33.28”, and that means the height off the ground to the center of hub for rolling circumference is 16 5/8”. Half the diameter of your 35” tire (realistically about 34.5”) is ~17.25”-17.5”.
That’s a 5/8”-7/8” difference that could easily be determined by weight of the vehicle compressing the tire, and lower than max inflation pressure.

 

[theblet]

I’m thinking about getting Jscan since i have an iPhone. Which OBD2 dongle do you guys use? I hate to spend $100 for an mx+ if it’s not needed.

 

[Jimmy07]

I’m thinking about getting Jscan since i have an iPhone. Which OBD2 dongle do you guys use? I hate to spend $100 for an mx+ if it’s not needed.

VLinker MC+. It’s exactly like the MX+ and allows connection to all modules on the truck.