branmin

SL550(09) had it for 10 months and the chk tire warning light came on..recalibrated and light went away. Was at work all day and this evening tire as flat as a pancake. Changed to the spare and noticed that I have a nail(and strangely the nail head has turned itselff around with the sharp end pointing upwards) right in the center of the tire.............have a great guy at mercedes dealership who lives around the corner from me and always helps me out by picking the car up and delivering it back to me(dealership 50 miles away) and told me to leave the tire at my store and he would pick it up on Tuesday as he is away until then and see if he can patch it up and if not get me a matching tire(which knowing Mercedes, they would try to do regardless)

My questions are.....

1. He told me to leave the car in the garage until next week and use another car until he sorted it out as mentioned above, but can one drive on the spare, albeit carefully and presumably under 50mph for say until next week, I would be doing about 40 miles a day?

2. Whats stopping me from going to say Goodyear or another local guy who services Mercedes and see what they say and if I have to get a new tire, get it myself as opposed to paying MB's price?

3. Would you be happy in patching the tire up or getting a new one regardless? Any ideas on cost.

4. And lastly, I used to get insurance coverage in the past on tires and decided against it this time....is it worth it, any exclusion clauses or do most of you have this coverage?

Thx very much.............

p.s. oh and just remembered, if I do this by myself, does the computer have to be reset in any way for tire pressure monitoring as obviously it's not operable in my present state and I have a warning light on....

m4xm1l10n

Pach it!!!!!! especially in the middle is just fine , just take it to a tire chop and have them pach it up no big deal , why buy new tire , that means every time you get a nail you will be buying new tire ? and why keeping the car parked for 1 week because of a simple flat tire .

jmf003

My $0.02...

1. Keep driving on the space saver spare? I wouldn't. It has very weak cornering and braking performance along with a limited tread life. Much better to either patch or replace the tire.

2. Check out another tire shop? Definitely. I always buy from a tire shop instead of the MB dealer.

3. Patch versus new tire? Tough call. Personally I wouldn't patch the tires on my SL because I sometimes drive it near the limit but have patched tires on the other cars in the family that don't get driven as hard.

4. Insurance on tires? Tough call. It's the only thing I buy extended coverage on and it's paid off for me. Would it pay off for someone else? Hard to say.

5. Does the TPMS computer reset when a new tired is mounted on the wheel? Yes, automatically.

Good luck!

Rook3300

1. At 40 miles per day, you could possibly go for a few days on it, but I wouldn't if it included highway speeds for any extended period. If you were only doing 10-15 miles per day, I'd say go for it, but any farther and especially at faster speeds, don't take the chance. The 50mph/50miles rule is about as old as the one about changing oil every 3000 miles and doesn't necessarily apply to modern spare tires. It's a liability thing, though I wouldn't push my luck.

2. Absolutely nothing at all. Depending on how much tread you have left on the other three, I'd actually look over some used tire options in that size and make/model. It wouldn't hurt to look and at worst you'd end up buying a new tire anyway. Try to buy the same make/model as the other three and just pay the least you can.

3. And that brings us to the question of patching. If there is a single hole in the middle, then yea, patch it up. But keep in mind that if there is more than one hole or any other damage to the tire (like from the rim or anything), they will not patch it. You will also want to get a quality patch from a place that knows what they are doing. I vaguely remember a tire guy telling me that there are several ways to patch a tire and that a certain way was the best -- I cannot remember it, but I'm sure you can ask around and find out.

4. That depends on whether you want to bet if you'll get another puncture within the warranty period or not. After about 6 years of buying the tire warranty, I found that I only ever punctured a tire once and it was difficult to get them to pay for it as it happened while the car was moving and there was extensive additional damage from the rim and the road as the tire spontaneously deflated and I was driving with the rim hitting raw rubber. Suffice it to say, I no longer buy the warranty and instead just buy used or at worst a whole new tire. It's a gamble.

5. As others have stated, the tire pressure monitoring system will go back to normal as soon as the standard rim/tire is mounted properly.

Rook

branmin

Excellent answers, info and advice..thx so much...

Alex1

hey i don't really post much but read often, but this one got to me a bit. This is a perfect example of why you shouldn't just turn off warning lights just because you know how. The tire had a nail thats why the light came on not because it felt lonely and wanted you to press the reset button. You have no idea how many of our customers come in with 18 psi in one tire, 40 in another and when we tell them they are shocked that the tpms didn't warn them, well its because they read how to reset the light and thats what they do instead of checking for a cause.

sorry for the rant some of you might hate me for it, but next time the light comes on its probably for a reason check the tire pressure, with a gauge just in case, to see if theres an issue.

ljj33

I would just take it to another tire store and have them patch it. If the nail is in the center of the tread and it is relatively new, it should be fine. I've patched low profile tires myself and have driven on it quite hard and have not had any issues. No point spending $300 on a new tire when $10 patch will do the trick.

Rook3300

I'm so glad I'm not in customer service as I would buy cheap, large cylindrical tire pressure gauges just so I can cram them up their *** when they come in with tire pressure problems. Saying "I don't know how" isn't an excuse for that sort of thing -- especially if you were smart enough to reset the TPM system in the first place. It's like saying you don't know how to pump your own gas. Even an el'cheapo gauge will let you know you are 10+ psi down on a tire and filling a tire isn't much more difficult than checking it.

Lookit that.... now you've got me ranting. Anyway, it's still a good tip -- don't reset warning lights/codes/errors just because you can. Take care of the problem first.

Rook

branmin

I think some of you have got the wrong end of the stick. For clarification, I didn't just push the reset button for the sake of it. I was knowhere near my car at the time, otherwise I would have checked it constantly. As soon as I was able, took a reading and as it had virtually no pressure, knew immediately that I had a nail lodged somewhere.

Anyway and it's not a rant, but a fact, even though the engineering and mechanics are superb on the SL, it does not have sensors on each wheel which gives out instant individual tire pressure readings as in my Vette and I would have known fairly quickly, but the light only came on within 5 minutes of my meeting yesterday.

Regardless, taken the tire in today and we will see tomorrow...

Alex1

actually it does have a sensor in each wheel, and when you calibrate you actually reset the system. So you basically calibrated it for a flat tire

mlandis

From reading my owner' manual, it sounds like what you are describing on your Vette, branmin, is similar to the advanced TPMS in the Canadian models, but Alex1 is right, even the U.S. version has something similar. The main difference I see is that the Canadian one actually says which tire has the problem, and gives you a readout of the tire pressure. The U.S. version just says whether or not there is a problem, and doesn't specify where. Lame.

branmin

I understand that it has a sensor in each wheel, but it doesn't give pressure read outs does it? Regardless, take me through the system, if you would and exactly how you do this, so that I totally understand for the next time. Thx.

mlandis

Actually I think you got it right -- it's just that, because the system didn't show you how fast the pressure was leaving, you didn't have any way of knowing that it would deflate so quickly. Yeah, it's not as fancy as your Vette's. It sounds like it was just poor luck that you weren't able to get back to it before it became obvious.

branmin

Actually I think you got it right -- it's just that, because the system didn't show you how fast the pressure was leaving, you didn't have any way of knowing that it would deflate so quickly.

Perhaps, but on the other hand, perhaps I didn't calibrate in the correct manner. Could you lead me through the exact procedure? Just want to see if I did what I am supposed to do correctly. Thx.

mlandis

I have a 2007, so it might not be the same, but according to the user manual, with cold tires, get to the "Standard" menu (which normally shows the temperature/odometer on the left and the trip odometer on the right). From there, use the arrows on the steering wheel to get to the "Tire pressure monitor active/Menu: r-button" display on the right. Press the reset button in the center of the instrument cluster. It will ask if you want to reset the monitor. Press the "+" button to reset, the "-" button to cancel. After a few minutes, it will take the pressure as "normal" and warn you if it goes outside its ranges, whatever they are.

If you reset it on warm tires, it will register a higher pressure than your tires will be at when they are cold, which I'd think would make it more likely to register a false alarm.

It sounds like the U.S. TPMS looks for the change in tire pressures since it was reset, rather than looking for a specific tire pressure. This makes sense, since different tires, driving conditions, and vehicle loads suggest different recommended pressures.

So when we are talking about resetting the system, we're talking about resetting what the system should consider normal, not resetting the system to any particular number. In your case, when you reset it, the system was told to think that an underinflated tire is normal. Oh well...

funnyguy1

Interesting situation. I had problems with my tire pressure monitor as well. You are supposed to check the pressure cold but the system tells you the pressure for each tire will show after driving around for a while. Well then the tire warms up so you have an inacurate reading. If mine comes on now I just check it correct it before driving, add air if needed and reset.

branmin

Thx guys...............anyway, they found a 2" nail, luckily right in the center, patched it up and trust I am good to go. Found the service I received from them excellent. I dropped the tire off the night before and the next day, they had me out of there in 5 minutes. $20.00 and I tipped the guy who changed the tire.

Just wish that there was a way to see the pressure in each wheel. For example, last year in my Vette, received a warning beep when the pressure dropped to 24 on rear drivers side..sure enough a nail..and this was on the highway. Overall can't complain as love the SL.

Rook3300

Good to hear bro. Have fun driving!

Rook

funnyguy1

My 05 does show the pressure in each wheel. It should tell you in the Owner's Manual how to pull it up.

mlandis

The Canadian model shows it. Are you from U.S.? I'd imagine the European models do, too. Either that or they economized on the 07, who knows...