Frontier Speedo/Tire Size

[oldnissanguy]

The more I read about this the less I know. My 2019 Frontier S has factory 235/75R15 tires and wheels. I plan to put on 265/70R16 tires and wheels which are factory size for the SV. Simple question (I think): Since it already reads slow, will this actually correct my speedometer or make it crazy? I've been reading that the speedometer is actually calibrated for the 16" tires????

[VStar650CL]

There should be a selection in the BCM for the various OE tire sizes and corresponding tire pressures for the TPMS. The dealer should be able to do that for you. I'm a little puzzled that it's reading slow, though. Nissan speedos are usually as predictable as dirt, they all over-indicate by 1 mph. Very strange if yours is under-indicating.

[oldnissanguy]

Sorry, said it backwards. Yes, over indicate. Thanks for the info. Wasn't aware that the dealer would do this. What about all the statements that they are actually calibrated for the 16" tires from the factory?

[VStar650CL]

It's possible the BCM was misconfigured at the factory, but I think I've seen that twice ever. Yours should be configured for whatever factory wheels came with the truck. There are certain instances where the rolling diameters of the rim and tire assemblies are identical even though the rim sizes are different, and in those cases there may not be a configuration option because it wouldn't do anything.

[mdmellott]

It's possible the BCM was misconfigured at the factory, but I think I've seen that twice ever. Yours should be configured for whatever factory wheels came with the truck. There are certain instances where the rolling diameters of the rim and tire assemblies are identical even though the rim sizes are different, and in those cases there may not be a configuration option because it wouldn't do anything.

Very curious. My stock 255/65R15 tire and wheel assembly is almost identical in diameter as the 235/75R15 set up. (29.05" vs 28.88") When I do the math, the 265/70R16 would make my '02 actually indicate a more accurate speed at 3.2mph faster than my current actual speed when my speedometer reads 60mph. According to the GPS on my phone, and confirmed by speed traps I occasionally see set up along the side of the roads I travel on, my speedometer currently over indicates by 3mph. This used to drive me crazy because I couldn't find a solution for this. Those bigger 265/70R16 tires would have corrected this gross error for me 3yrs ago when I bought new treads. However, I stayed with the stock size because of fuel economy concerns at slower, around town, and stop and go driving.

I don't think I have a BCM on my '02 and I know I don't have a TPMS. Is there a way to correct my speedometer to more accurately indicate my actual speed?

[VStar650CL]

You can easily intercept the Blue/White wire at the back of the cluster, which is a digitally-corrected VSS signal from the TCM...

...and install one of these at the back of the cluster, which will correct the needle to 0.1% accuracy (if you want to get down to a level that ridiculous!) without affecting the signal to the ECM.

https://www.ebay.com/itm/143631478304

[mdmellott]

You can easily intercept the Blue/White wire at the back of the cluster, which is a digitally-corrected VSS signal from the TCM and install one of these at the back of the cluster, which will correct the needle to 0.1% accuracy (if you want to get down to a level that ridiculous!) without affecting the signal to the ECM.

https://www.ebay.com/itm/143631478304

Excellent! Thank you!

[VStar650CL]

You're most welcome!

[VStar650CL]

You can easily intercept the Blue/White wire at the back of the cluster, which is a digitally-corrected VSS signal from the TCM and install one of these at the back of the cluster, which will correct the needle to 0.1% accuracy (if you want to get down to a level that ridiculous!) without affecting the signal to the ECM.

https://www.ebay.com/itm/143631478304

Excellent! Thank you!

PS - For anybody considering this, be aware that on most later models you can only compensate a few mph +/- by fooling the VSS. That's because later ECM's use the ABS wheel speeds to cross-check the VSS signal from the cluster, and if it's substantially off you'll get a P0720, P0500 or similar code. Non-ABS vehicles can generally be fooled by any amount because the ECM has no cross-check. Similarly, early vehicles like Mdmellott's can be fooled because you can alter the cluster signal without telling the ECM, and the ECM won't know what the needle is reading like it would with an all-CAN cluster.

[mdmellott]

My stock 255/65R15 tire and wheel assembly is almost identical in diameter as the 235/75R15 set up. (29.05" vs 28.88") When I do the math, ...

Typo correction: My stock tires are 255/65R16. I knew that when I wrote this. I did the math right based on the 16" wheels and a 255/65 tire profile but I just fat fingered the keyboard when I wrote 255/65R15, which was never a stock size on Pathfinders.

[oldnissanguy]

In my case the current 235/75R15s make 699 revolutions per mile and the 265/70R16s would make 659. A fairly significant difference.

[jethbon]

Any update, oldnissanguy? I'm just curious if 265/70R16 will rub. That's the tire size I'm planning to get for my 16" Ultra wheels with a 15mm offset.

[oldnissanguy]

That’s the size that comes on the SV model so I’m not expecting any issues. However the factory offset is 30 something so the 15 might cause a problem??? I’m going to use some repurposed Nissan wheels and they clear the calipers fine.

[D21hardking]

Go to "tiresize.com/calculator". You can play around with sizes and it'll show you how much your speedo will be out with the new size. Used this site to figure out what 17's to use.

[oldnissanguy]

Already done that. See above. 699 vs 659.

[D21hardking]

Oops. Missed that sorry

[oldnissanguy]

Tires and wheels are on as of last night. I got the wheels from a friend. They're 09 - 14 X-Terra and the offset is 30mm; same as the 19 Frontier alloy wheels. They came with the centers but I had to buy lug nuts. Tires are 265/70R16 Cooper Discoverer AT3. I decided against the OWL look. Everything fit including the TPMS sensors. It looks better IMHO and sits a little bit higher. May paint the wheels black in the future but I'm okay with them for now. Preliminary results are that the larger tires corrected my speedo error and it's reading dead on. Further research required.

BEFORE:



AFTER:

[oldnissanguy]

Update: Checking at higher speeds against my GPS, it looks like it is doing 67 when the speedo is registering 65 and 72 when registering 70. I can live with that.