# What is this ring around both my tires? **URL:** \ **Category:** General Discussion\ **Tags:** m, bmw\ **Created:** [April 10, 2020, 7:35am UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686 "2020-04-10T07:35:45Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Ruby4](https://avatars.discourse-cdn.com/v4/letter/r/db5fbb/32.png) [@Ruby4](https://community.cartalk.com/u/Ruby4)\ **Post date:** [April 10, 2020, 7:35am UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/1 "2020-04-10T07:35:45Z")
I have just recently purchased two new front tyres for my car, Michelin Pilot Sport 4S (Build date late 2019). (I think) ever since new or very soon after, I’ve noticed a worn black identical ring around the sidewall on both of them. When freshly washed it looks black, and when unwashed it develops a powdery like substance that can be wiped away. Does anyone have any clue? Thank you ! ![IMG_20200410_173517](https://global.discourse-cdn.com/cartalk/original/3X/8/8/88fc1ad7e8dbe9460ccd96e704bf08971ede7e48.jpeg) ---
**Author:** ![common-sense-answer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/common-sense-answer/32/716_2.png) [@common-sense-answer](https://community.cartalk.com/u/common-sense-answer)\ **Post date:** [April 10, 2020, 9:53am UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/2 "2020-04-10T09:53:04Z")
Nice tires! Good photos! Great description! That’s interesting and I could only hazard a guess, but perhaps @CapriRacer, a tire expert who frequents this site could offer a helpful explanation. He maintains a website, [http://barrystiretech.com/index.html](http://barrystiretech.com/index.html) and I believe he can be contacted there, but it wouldn’t surprise me if pulls up here soon ![image](https://global.discourse-cdn.com/cartalk/original/3X/f/f/ffc51c2c2bc0e4247495fc2548d1767212520c7b.png) _ **CSA** _ 🌴 🕶 🌴 ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [April 10, 2020, 12:10pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/3 "2020-04-10T12:10:12Z")
Are they stock size? ---
**Author:** ![CapriRacer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/capriracer/32/22_2.png) [@CapriRacer](https://community.cartalk.com/u/CapriRacer)\ **Post date:** [April 10, 2020, 12:11pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/4 "2020-04-10T12:11:02Z")
That looks like where the tires were touching something when they were stacked - probably the neighboring tire. The black is the oil in the rubber matrix and the white is the antioxidant also embedded in the rubber matrix. Nothing to worry about. Eventually both will go away. ---
**Author:** ![Ruby4](https://avatars.discourse-cdn.com/v4/letter/r/db5fbb/32.png) [@Ruby4](https://community.cartalk.com/u/Ruby4)\ **Post date:** [April 10, 2020, 12:46pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/5 "2020-04-10T12:46:40Z")
Thanks for your reply, this is good to hear. Even if I try clean off the black, it won’t come off. Will it still go away by itself eventually? ---
**Author:** ![Ruby4](https://avatars.discourse-cdn.com/v4/letter/r/db5fbb/32.png) [@Ruby4](https://community.cartalk.com/u/Ruby4)\ **Post date:** [April 10, 2020, 12:47pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/6 "2020-04-10T12:47:24Z")
Yes stock size ---
**Author:** ![CapriRacer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/capriracer/32/22_2.png) [@CapriRacer](https://community.cartalk.com/u/CapriRacer)\ **Post date:** [April 10, 2020, 12:48pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/7 "2020-04-10T12:48:18Z")
> [@Ruby4](#): > > Thanks for your reply, this is good to hear. Even if I try clean off the black, it won’t come off. Will it still go away by itself eventually? Yes. Right now there is an excess, and that will dissipate over time. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 10, 2020, 12:57pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/8 "2020-04-10T12:57:06Z")
@CapriRacer Capri . in the persons first post they say 2 new front tyres . They must not be in the US but I thought it was recommended every where to put 2 only new tires on the rear of a vehicle. Should they be told to have them put on the rear . ---
**Author:** ![CapriRacer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/capriracer/32/22_2.png) [@CapriRacer](https://community.cartalk.com/u/CapriRacer)\ **Post date:** [April 10, 2020, 1:01pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/9 "2020-04-10T13:01:20Z")
> [@VOLVO\_V70](#): > > Capri . in the persons first post they say 2 new front tyres . They must not be in the US but I thought it was recommended every where to put 2 only new tires on the rear of a vehicle. Should they be told to have them put on the rear . Yup, The recommendation doesn’t know international borders. Good catch! ---
**Author:** ![Ruby4](https://avatars.discourse-cdn.com/v4/letter/r/db5fbb/32.png) [@Ruby4](https://community.cartalk.com/u/Ruby4)\ **Post date:** [April 10, 2020, 1:05pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/10 "2020-04-10T13:05:04Z")
My car has a staggered set up. 275/35/19 rear, 255/35/19 front. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 10, 2020, 1:26pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/11 "2020-04-10T13:26:11Z")
I am surprised that the tire shop did not almost insist 4 new tires be mounted . It might be a safe move to plan on new tires for the rear soon. You should find a video on the Michelin web site showing what can happen with new tire on the front. ---
**Author:** ![Ruby4](https://avatars.discourse-cdn.com/v4/letter/r/db5fbb/32.png) [@Ruby4](https://community.cartalk.com/u/Ruby4)\ **Post date:** [April 10, 2020, 1:53pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/12 "2020-04-10T13:53:16Z")
I have brand new rear tires as well. I did not mention that because my concern with this post is only with the front tires ---
**Author:** ![FRANKM](https://avatars.discourse-cdn.com/v4/letter/f/2bfe46/32.png) [@FRANKM](https://community.cartalk.com/u/FRANKM)\ **Post date:** [April 15, 2020, 3:12pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/13 "2020-04-15T15:12:59Z")
My first thought would be underinflated. Check the pressure with a known accurate gauge. ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [April 15, 2020, 3:17pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/14 "2020-04-15T15:17:10Z")
Did you not read CapriRacer posts . He is an actual tire expert . ---
**Author:** ![williamBhopkins](https://avatars.discourse-cdn.com/v4/letter/w/85e7bf/32.png) [@williamBhopkins](https://community.cartalk.com/u/williamBhopkins)\ **Post date:** [April 17, 2020, 4:16pm UTC](https://community.cartalk.com/t/what-is-this-ring-around-both-my-tires/162686/15 "2020-04-17T16:16:34Z")
Looks like the lubricant some tire shops use when mounting tires…