hokusbenz

its really funny you say that jack230 because i just got the same sponge from the auto store after i complained that the black magic gel was slinging all over the sides of my car... i got it wondering how the hell is this supposed to be better than the square sponge in the box but as long as you use it and run it acroos the tire a bunch of times to get rid of excess it shouldnt sling off. and the shine of black magic is way way bettr than meguiars, unless you like the satiny finish. i like the smell too yummy lol :p i found that a lot of meguiars chemicals have a good smell to them, check out the gold class interior wipes, another outstanding product...

BlackC230Coupe

i have the sponge to its that yellow and black thing if thats what u all are talking about. and i only use black magic it shins great they look wet. and i guess i will admit the cherry smell to it is not bad eaither. I remember the Meguirs car wash shampoo smelt good to. i think meguirs needs to make a spray tire shine similar to black magic.

chronopassion

I appreciate that this is going to be a simple question for people who know the answer. Nevertheless, when one replaces the 17 inch tires on their C7 C230K, does one actually have to get the exact "225/45 ZR17" tires or can one get 245/45 ZR17 or other variations for example as long as they are still 17 inch tires?

CP

P.S. Is there some "wiggle room", like 235 or 245 are fine on a 225, but 255 would not work?

VoyagerDude

This was discussed before, but here are my calculations:

Current tire size is 225/45/R17, so

225 * 0.45 = 101.25 mm is the sidewall height,

so the closest sidewall to 101.25mm with the wider tire would be:

255 * 0.40 = 102.00 mm,

ie, 255/40/R17

However a 255mm wide tire is apparently too wide for the 7.5" (190.5mm) 17" rim. Please correct me if I'm wrong.

Mike T.

Theoretical calculations of tire diameter/circumference are just that - theoretical. The manufacturers themselves actually publish the REAL diameter/circumference figures (check with a tire store) and you would be shocked how inaccurate some of the theoretical calculations can be!

The worst example I can think of right now was when a friend of mine got 175/45 13 Pirelli P7s 20 years ago for a Renault 5 - the nominal width was 175 mm, but measured with a ruler, it was more like 195 mm. So even if the 45 aspect ratio was correct, the actual sidewall height would have been wrong, if the calculation had been based on the nominal 175 width.

This trend is still true today, so be advised to get the tire manufacturers' own official figures for width/diameter etc. before committing to anything other than stock "pneumatiques".

Duffer

You might try tirerack.com, or discounttire.com for sizing, or edgeracing.com,

If you want more grip, you might try a better tire - I have found that by switching tires with the same size - 245/17, I get a lot more grip - I went from Pirelli PZero Rossos to Bridgestone S-03 Pole Positions and the difference in grip was tremendous and it was also a bit quieter.

VoyagerDude

The point of my calculations was to determine the required tire width keeping the same tire diameter.
Otherwise the computer has to be updated, so the speedo and odometer work properly.

Maybe you're right and pure math does not apply here in that case the car computer would always have to be updated with the correct tire size.

VoyagerDude

I asked a local tire shop to check the North Americal tire regulations and according to them you can go to a 245.40.17 tire on a 7.5" wide rim. (But not 235.45.17)

chronopassion

I snapped a picture of my tire damage. Apparently, I hit a pot-hole and scraped the rim as well as lost a little chunk of the tire. I took it into a tire store which said basically since it is not bulging nor is any sign of steel showing, that the tire should be fine.

Does that sound reasonable to you guys? I do not want to risk my life by not spending a couple hundred bucks if necessary. Then again, I do not want to throw away money if it is not necessary.

Any help is appreciated.

CP

P.S. If the image does not load, click the link below.

http://home.indy.rr.com/chrono/tire.jpg

BlackC230Coupe

i am pretty sure that that is fine its not that bad and those side walls are extremly thick. i had the exact same thing happen on my jaguar and i just left it and it was fine. when it came time to get new tires i looked inside and there was no damage at all so i am pretty sure it is fine. but keep asking around to be 100% sure.

SoCal240/6

That's not something I'd worry about.

telcontar

depending on the profile of your tires (what size tires / rims do you have) you might get a bubble over time. Happened to me, big pain in the ***. You should go to the dealer and see if they will check your alignment for free, if it's out of align, get it fixed and if the alignment goes out in short order again you probably have a bent rim.

The best way to find out is to get your dealer/garage/tire shop to take the wheel off the car and spin balance it and determine if it's bent.

With all that said, the damage doesn't look that bad so don't stress too much ;-)

If you need to get your rims fixed, check these guys out they do really good work:

http://www.wheelcollision.com/index.html

chronopassion

Thnaks for the info so far. As far as the rim size, it is the 17 inch from the C7 package. The tires are the Pilot Sports from Michelin.

My gut feeling is that there is no real damage. I do not notice any pull whatsoever. Of course, I never noticed any from the beginning.

The scratch on the rim is extremely superficial and the lost chunk of tire looks like it is on the superficial potion of the sidewall where they put a raised region.

So, all in all, I think I am OK. Anybody else want to sooth my fears away?

CP

MsMercedes

I wouldn't worry about that. I too would check the alignment though.

I used to work in a tire plant for about 6 years, and when there was an abnormality in the tire we would "dig" the sidewall....basically gouge a chunk out.....and then stuff it with green rubber and spot cure that area. You would be suprised how deep you can dig before you hit steel. The area you have damaged your tire is close to the bead area, which is considerably thicker and harder than the rest of the sidewall.

Watch those potholes!!!

Michelle

chronopassion

Well, on my drive into work, I guess I decided the alignment must be reasonable. In the right lane I drifted to the right. In the left lane, I drifted to the left. Both at the approximately same rate. So, I will simply have Mercedes check the alignment sometime in the next ten months during the one year alignment warranty period.

Thanks for all you help,

CP

Geo

picking my car (w/ C7) next week. my dealer said all cars in their dealership comes w/ all-season tires since we are in the northeast. I told him what I have read about and he still promises me that it is all-season. He said he even asked the manager as well. He would not do any change of tires for me.


is it true? what should I do cause I really don't want to go thru the hazzle of changing tires every now and then.

thanx.
Geo

Lynn

Nowhere in any MB literature have I found a statement than the C7 tires are all season tires. All mention of the tires state that they are high performance tires. My Michelins do not have the M+S designation molded into the sidewalls.

jack230

The Michelins are great tires, but my salesman did tell me that the Continentals should last somewhat longer than the Michelins, if that's important to you

I'll probably be replacing the Michelins with Kumhos when the time comes to save some $$.

viper

Lynn it is possible that they are now supplying all-season tires in the C7 package because some customers were plenty upset at having to purchase winter tires when the snow fell. Or they just used up all the Conti's and Michelins and are starting to use the 2003 tires that are starting to fill the production pipeline.

dmichael

I got Contis with my C7 package - I asked the dealer to swap and they said they had no donor cars available. The Contis I have are W-rated not Z.

Mark08859

Lynn is 100% correct. You can only compare tires within the same brand.

C 320-Sport

Well on wedneday night I was on my way to dinner and I was driving on Sunset Blvd going 55 mph blasting my radio then all of a sudden Mr. Pothole shows up, All I heard was thump thump thump and I pulled over to see my shiny 19s had been scratched and my tire was blown. Then my day got worse, the AAA guy comes after 45 mins and says he wont change my tire because they are aftermarket rims and says he doesnt want to mess them up, ummmmm I was like what the hell are you seriuos? I ended up changing my tire myself and 3.5 hours later I am finally home. I was now wondering does anybody know a good place where I can find Pirelli tires for 19s for a cheap price? Let me know, I am rolling on 3 19s and 1 16, heheh I would appreciate your help. Thanks

E_Corleone

DAMN! Thats awful. I just got 19" with low profile 235x35x19 P7000. Tire rack has them on sale for $198 i think. I hope you have better luck next time, I hate to hear stories like this it makes me drive even more careful than I already do. Do you have staggered tires?

session

at least AAA didn't take 4 hours to show up like they did once for me while stuck on I-64. it was 85 degrees, at night too! they did change the tire though. that's an idiotic policy of not changing tires on aftermarket rims... was it an AAA guy or just some local towing company that AAA contracts out?

Mark08859

If you have a C320, TeleAid should have been standard for you. Why didn't you call MB and have them do it?