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Discussion Starter · #1 ·
I am thinking of buying wheel/tire setup for TireRack. Does anyone know what we need to do to be able to keep TPMS working on winter tires? Obviously I do not want to move my TPMS sensors from 1 wheel set to the other.
 

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I am thinking of buying wheel/tire setup for TireRack. Does anyone know what we need to do to be able to keep TPMS working on winter tires? Obviously I do not want to move my TPMS sensors from 1 wheel set to the other.
Install a new OEM set and go to a dealership to program the car to them. You'll have reprogram when you switch again as well.

As of a month ago, there wasn't yet a programming profile for the aftermarket reprogramming gizmos, but you may wish to check again, since some time has went by since I tried. It's not the same profile/setup as earlier Subies, according to the Subie performance shop I went to.
 

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See if you can get ones cloned or programmed.

At least that way you wouldn’t have to update the computer with the codes. Otherwise yeah you’ll have to have them re register the sensor id every time you change the rims.
 

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Is it necessary to update the computer when rotating wheels or does it figure it out? I've heard mixed information.
Pretty sure it figures it out.
 

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Discussion Starter · #6 · (Edited)
Is the Ascent system the same as the 18 outbacks? I am wondering because a reputable tire shop says they can just clone the existing vehicle sensors one time and use that ID in the new sensors, so we would never have to reprogram again. I just don't know if they don't realize it's different.
 

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Unless Subaru updated the system for the ascent you need to go to a tire store/dealership with the TPMS reset tool to manually register the TPMS sensors to the car. All other Subaru's I've owned 2011+ have required this and they do not automatically learn the sensors installed.

Locally I can go to Discount tire and/or CostCo to have them register my TPMS sensors for free after winter/summer wheels swaps. Kind of a PITA but at least its no additional cost through them. I think most dealers will charge you bc dealerships. You could purchase the tool and do it yourself but that tool is pretty pricey.

I wish Subaru would go to non-sensors for TPMS like other manufacturers. Mazda doesnt have any sensors in the wheels on newer models and bases the TPMS off wheel speed vs. pressure. Makes it super easy for wheel swaps and no additional costs for separate sets of sensors.
 

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Discussion Starter · #8 ·
The tire shop is saying they will clone the sensors 1x and you won't have to do it again each time you swap wheels every 6 months.
 

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I wish Subaru would go to non-sensors for TPMS like other manufacturers. Mazda doesnt have any sensors in the wheels on newer models and bases the TPMS off wheel speed vs. pressure. Makes it super easy for wheel swaps and no additional costs for separate sets of sensors.
Our '06 Vibe uses ABS to measure wheel rotation differences like you mentioned as well.
It works decently but you don't get the convenience of pressure readings and it takes a bit longer to learn/reset and read a problem.
 

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do we have to do TPMS Sensor Relearn after every tire rotation ?( to make sure it corresponds to display) or our car smart enough to Relearn itself it or let as do it?
 

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Of tire pressure and such...

I wish Subaru would go to non-sensors for TPMS like other manufacturers. Mazda doesnt have any sensors in the wheels on newer models and bases the TPMS off wheel speed vs. pressure. Makes it super easy for wheel swaps and no additional costs for separate sets of sensors.
I have a feeling that system wouldn't work quite as well on a Subaru, since it's real all-four wheel drive. The indirect sensors are not very accurate in comparison, and we already know that true AWD systems have very tiny tolerances for wheel size differences.

The pros of real AWD is that it's always on, always active, and in the case of our VDC, ABS, X-Mode SubieSystems, always responsive.

The cons are you must always rotate tires regularly to maintain tread depths to within 2/32" of an inch of each other. It's also why proper inflation is so very important on a Subaru and there will likely never be the current indirect system on a Subie (except maybe the BRZ?), even though they're cheaper.

Mazda cars and SUVs, Toyota cars and SUVs, many Hondas, and most VW cars and SUVs use a front wheel drive with rear wheel assist system, so, there's no 24/7 all the time impact to the driveline and differentials, because usually, only the front wheels are driven, or the front wheels are driven with 90% power. Nissan uses a 100% FWD system with very limited AWD at under 25mph with a button press to activate it.

We don't have the luxury of the cheaper, easier to work with, less accurate indirect sensors that others' use. :plain:

Neither do Porsches with real AWD.

https://tires.tirerack.com/tires/Tread Depth Subaru

https://www.edmunds.com/car-safety/tire-pressure-monitors-can-you-rely-on-them.html

The lower-cost, indirect TPMS doesn't actually monitor air pressure. Rather, the indirect TPMS uses the antilock braking system's wheel-speed sensor to detect that one tire is rotating faster than its mates. (An underinflated tire has a smaller circumference so it has to roll faster to keep up.) Thus, there's a large margin of error in indirect systems.

Meanwhile, a direct TPMS measures a tire's actual pressure. Such systems are usually accurate to within 1 psi. Current direct systems use a gauge mounted to the wheel or tire valve. This gauge sends a signal to the car's computer. How the data is interpreted and displayed in the car with a direct TPMS depends on whether it is a low-line or high-line unit.

A high-line system has sensors mounted in each of the wheelwells and displays the individual pressure of each tire on the instrument cluster. Low-line systems are found on less expensive cars and will only prompt the low-pressure warning light. It is then up to the driver to figure out which tire is low. Much more useful to drivers, clearly, are systems that actually display the pressure of each tire.
 

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i don't know how Mazda can get away with it ... if some one over or under inflate all 4 tires you can still have blow out
wheel speed vs. pressure was used back in ~2000 in GM, yet they all put sensors in the cars after 2008+


but they for sure can make it self programmable or user programmable like many other manufactures do...
 

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I have a feeling that system wouldn't work quite as well on a Subaru, since it's real all-four wheel drive. The indirect sensors are not very accurate in comparison, and we already know that true AWD systems have very tiny tolerances for wheel size differences.

Would TPMS be an issue if I use 20" winter tires? I am not finding an easy solution to install 18" winter tires and in Ottawa the winters are brutal. Even worse is the reservation queue to swap tires in Costco. So I want to buy the 20' Blizzaks for now and keep a few year and change to 18" after that. This ( winter 20 ") will not require a TPMS calibration right?

This is what I basically planning. Load index is 102T - 1874 lbs.

https://www.bridgestonetire.ca/tire/blizzak-dm-v2/p245-50r20

https://tires.costco.ca/Product?lang=en-ca&ItemNo=451506&SearchID=245|||50|||20|||3|||en-ca
 

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Would TPMS be an issue if I use 20" winter tires? I am not finding an easy solution to install 18" winter tires and in Ottawa the winters are brutal. Even worse is the reservation queue to swap tires in Costco. So I want to buy the 20' Blizzaks for now and keep a few year and change to 18" after that. This ( winter 20 ") will not require a TPMS calibration right?

This is what I basically planning. Load index is 102T - 1874 lbs.

https://www.bridgestonetire.ca/tire/blizzak-dm-v2/p245-50r20

https://tires.costco.ca/Product?lang=en-ca&ItemNo=451506&SearchID=245|||50|||20|||3|||en-ca
It's not the tire that's related to the TPMS calibration. It's the TPMS sensors themselves.

If you are changing your rims, you need to install TPMS that will work with the Ascent. Best thing to do is to have them cloned to match the ones in the existing rims, that way you can change from one tire set to another whenever you want.

If you are just swapping the tires on the existing rims, then you've already got TPM sensors installed on those rims, and are good to go.
 

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It's not the tire that's related to the TPMS calibration. It's the TPMS sensors themselves.

If you are changing your rims, you need to install TPMS that will work with the Ascent. Best thing to do is to have them cloned to match the ones in the existing rims, that way you can change from one tire set to another whenever you want.

If you are just swapping the tires on the existing rims, then you've already got TPM sensors installed on those rims, and are good to go.
Thanks Robert. Got it now. I am simply going to swap the tires for now for simplicity. For next round of tire purchase, may be I will get 18" rims and the TPM sensors for that rims.
 

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do we have to do TPMS Sensor Relearn after every tire rotation ?( to make sure it corresponds to display) or our car smart enough to Relearn itself it or let as do it?
I’m hoping to find the answer to this someday also! It doesn’t seem like anyone has made it to a tire rotation yet
 

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I’m hoping to find the answer to this someday also! It doesn’t seem like anyone has made it to a tire rotation yet
I have. It registers all four wheels still. I am presuming that since the readers are in/near the wheel wells, it's aware of position as well.
 

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I’m hoping to find the answer to this someday also! It doesn’t seem like anyone has made it to a tire rotation yet
I have. It registers all four wheels still. I am presuming that since the readers are in/near the wheel wells, it's aware of position as well.
Did you happen to try raising or lowering pressure in any single tire to see if the correct position is still displayed on the dash?
 

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I have. It registers all four wheels still. I am presuming that since the readers are in/near the wheel wells, it's aware of position as well.
I don't know.
I remember reading about another car having to register the sensors in a particular order so that the car would know which was which.
 
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