Larger tire speedo issues?

[ajm33605]

Looking at upgrading wheels and tires on my Outer Banks. Assuming this throws off the speedometer? If this is the case is there a fix available?

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[Erock]

https://superchips.com/shop/v/ford/bronco/2022/2-3l/

Or Forscan… to the best of my knowledge

 

[Tricky Dick]

How much bigger? I noticed my speedo was more accurate after going 2" larger. Went from 2 mph slow at 60 to 1 mph fast.

 

[Odd Ball]

Looking at upgrading wheels and tires on my Outer Banks. Assuming this throws off the speedometer? If this is the case is there a fix available?

Sounds like you’ll be selling a “low mileage“ Bronco in the future…

 

[2020FordRaptor]

How much bigger? I noticed my speedo was more accurate after going 2" larger. Went from 2 mph slow at 60 to 1 mph fast.

It is required by law for speedometer to read higher. I don't know how much higher but none the less, higher.

 

[2020FordRaptor]

https://superchips.com/shop/v/ford/bronco/2022/2-3l/

Or Forscan… to the best of my knowledge

But it voids warranty. Right?

 

[Erock]

@2020FordRaptor
I don’t know. Op asked for possible fixes, so I just threw a couple out there. If they’d have said “fix that doesn’t void the warranty “, I wouldn’t have given any answer because I haven’t looked that far into them.

 

[2020FordRaptor]

@2020FordRaptor
I don’t know. Op asked for possible fixes, so I just threw a couple out there. If they’d have said “fix that doesn’t void the warranty “, I wouldn’t have given any answer because I haven’t looked that far into them.

I know that I was just putting that out there so he knew.

 

[DaveInSA]

It is required by law for speedometer to read higher. I don't know how much higher but none the less, higher.

What?

https://www.law.cornell.edu/cfr/text/49/393.82
49 CFR 393.82

§ 393.82 Speedometer.

Each bus, truck, and truck-tractor must be equipped with a speedometer indicating vehicle speed in miles per hour and/or kilometers per hour. The speedometer must be accurate to within plus or minus 8 km/hr (5 mph) at a speed of 80 km/hr (50 mph).

Correction, that's for commercial vehicles.

For passenger vehicles I do not believe there is a law in the united states that governs this. Though according to this site:
https://www.thrillist.com/cars/your...accuracy-in-german-american-and-japanese-cars
Manufacturers have self-emposed SAE J1226 which calls for a range of plus or minus 4%
http://standards.sae.org/j1226_201108/

 

[‘21OBX]

I don’t see how it would void any warranty in forscan at least. All you are doing is telling the vehicle a different circumference of the tire. That has no effect on in any systems as far as failure. My dealer had no fix for the Speedo even tho they sold us my wife’s with 35” tires. They have not given any problems honoring the warranty.

 

[DaveInSA]

Looking at upgrading wheels and tires on my Outer Banks. Assuming this throws off the speedometer? If this is the case is there a fix available?

I fixed mine with Forscan. Was like a $40 OBDII to usb adapter from amazon and just had to change one number via Forscan. Was able to get it more accurate than factory. Though it'll require some adjustment as tread wears down.

 

[Gorgar84]

What circumference did you use? I have 35x12.50r18 and used 2768 but didn't really help. Tried a few numbers but can not seem to dial it in. at 74mph speedo i was running about 79 before i adjusted it.

edit 2600 is real close

 

[ChrisB351]

But it voids warranty. Right?

Technically the oversize tires can void your warranty. If its not calibrated then they can say you have more miles on the vehicle than the odometer is reading. Granted its irrelevant untill you get close to 36k but Ive see warranty claims denied for less.

 

[dgorsett]

Do an actual on the ground test, before and after before changing anything. 33" tire would only be a 3% change which will probably be within a margin of error, 35 would be 9ish%

 

[Deleted User 5719102]

I fixed mine with Forscan. Was like a $40 OBDII to usb adapter from amazon and just had to change one number via Forscan. Was able to get it more accurate than factory. Though it'll require some adjustment as tread wears down.

Do you have a link to this item you can share? Thanks

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