# Tire and brake wear particulate matter



## bwilson4web (Mar 4, 2019)

About 5 years ago, there was a suspicious press release that claimed EVs and hybrids were generating higher amounts of tire, brake pad, and road wear material than lighter, gas and diesel cars. An obvious hit piece against fuel efficient cars, their methodology used a tunnel and laser air particulate detectors. No one paid them any attention except as a the butt of jokes. Well they are back.

Source_1: https://www.emissionsanalytics.com/news/pollution-tyre-wear-worse-exhaust-emissions
​_. . . Using a popular family hatchback running on brand new, correctly inflated tyres, we found that the car emitted 5.8 grams per kilometer of particles._​​_Compared with regulated exhaust emission limits of 4.5 milligrams per kilometer, the completely unregulated tyre wear emission is higher by a factor of over 1,000. Emissions Analytics notes that this could be even higher if the vehicle had tyres which were underinflated, or the road surfaces used for the test were rougher, or the tyres used were from a budget range - all very recognisable scenarios in 'real world' motoring._​_. . ._​
Source_2: https://uk-air.defra.gov.uk/assets/...90709_Non_Exhaust_Emissions_typeset_Final.pdf










If we take the 'press release', the particulate matter per car for a year would be:

12,000 mi/yr * 1.6 mi/km = 19,200 km/yr
19,200 km/yr * 5.8 g/km = 111,360 g/yr
(111,360 g/yr / 1000) / 4 = 27.8 kg/yr if JUST one of 4 tires
27.8 kg/yr * 2.2 lbs/kg = 61.2 lbs :: exceeds the weight of a tire
The trick is to realize the include road surface material. You want 5.8 g/mi, drive down a dirt or gravel covered road. You'll get pounds of dirt thrown up. But misleading from the press release is the distribution by:

brakes
tires
recycled road debris/powder 
This is where table 8 helps by adding the distribution. Yet we should care because the press release claims it is weight and of course our BEV and PHEVs are heavier than a gas or diesel. They are leading to claim 5 years ago that our rides are causing this particulate problem.

At least today they recognized SUVs even if they don't share our USA inventory of heavy pickup trucks. So I've weighted my Std Rng Plus Model 3 with driver and passenger, 4,000 lbs, and empty, 3,500 lbs. In effect we are in the weight of similar class cars.

Is that a problem with the current USA administration, not as long as they advocate keeping today's emissions standards. But there are anti-BEV and anti-HEV groups who would exploit bad math and science for their goals.

Bob Wilson


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## Klaus-rf (Mar 6, 2019)

Are they suggesting that non-BEV vehicles DO NOT have any tyre/brake particulate emissions??


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## bwilson4web (Mar 4, 2019)

Klaus-rf said:


> Are they suggesting that non-BEV vehicles DO NOT have any tyre/brake particulate emissions??


They are trying to blame vehicle weight. About 5 years ago, they tried to blame the weight on battery packs ... any non-lead acid 12V battery.

Bob Wilson


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## Klaus-rf (Mar 6, 2019)

Are they separating high-wear tires from high mileage ones? A 150 UTOG rating "Summer performance" produces MUCH more tire wear than a UTOG 800 All-Season , for example. 

While I agree that weight is a factor, tires are not just tires.


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## bwilson4web (Mar 4, 2019)

Personally, "Emissions Analytics" is selectively choosing their data instead of doing a real engineering analysis. They have issued a misleading press release and that is almost as indefensible as Autoline.TV publishing it.

Bob Wilson


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## John (Apr 16, 2016)

By far the highest amount was from brake wear.
But Teslas to a first approximation don't HAVE brake wear.
Old analysis, new technology. The motor is (mostly) the brake.


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## NickJonesS71 (May 11, 2020)

Klaus-rf said:


> A 150 UTOG rating "Summer performance" produces MUCH more tire wear than a UTOG 800 All-Season


How many cars on the road are running a 150 tread wear?


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## Klaus-rf (Mar 6, 2019)

NickJonesS71 said:


> How many cars on the road are running a 150 tread wear?


 Insufficient data to answer your query. When I attend the local auto-x events, at least 75% of cars have that rating or lower on the cars. Except "stock" classes which, iirc, still require 200 or higher. While MOST of those "200" ratings are closer to an actual 100.

As far as percentages on public highways, I have no idea and I'm not aware of any group or organization that tracks that data - maybe TireRack??
. I'm sure it depends highly on the local climate (and if people change summer/winter tires).


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## NickJonesS71 (May 11, 2020)

Klaus-rf said:


> As far as percentages on public highways, I have no idea and I'm not aware of any group or organization that tracks that data


I'm sure we can agree that's less than a few %. Which begs the real question is how significant is tire particulate emissions really vs every other emission


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## Klaus-rf (Mar 6, 2019)

NickJonesS71 said:


> I'm sure we can agree that's less than a few %. Which begs the real question is how significant is tire particulate emissions really vs every other emission


 IMHO probably significantly less that "every other". Some of those "other" categories are airborne [gaseous] and do not eventually settle out like most particulates do.

The only folks that should, imho, be really worried about tire/brake dust particulates are joggers and [bi]cyclists exercising on the same roadway. Or on-ramp hitchhikers (do we still have those?? I must be showing my age.)

Get a hundred feet or so away from the roads and it's no longer an issue afaik. Like dirt roads - it all falls down soon enough.


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## NickJonesS71 (May 11, 2020)

Klaus-rf said:


> Or on-ramp hitchhikers (do we still have those?? I must be showing my age.)


Oddly enough I saw a man walking ON the highway just the other day. I'll never understand people's disregard for safety


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