amazer98

Hi, I'm a newbie here, since I just bought my first MB two days ago. My shiny black c300 Sport 4matic has worn out snow tires on its factory wheels. Even tho the rear wheels are wider than the front ones, all 4 snows are the same size-- 225/45R17.

I plan to get new tires tomorrow... Probably Michelin Primacy MXM4s, and was thinking I would get them all the same size... just like the snow tires. That way, I could rotate them and extend the mileage.

Plus, since the original wheels have some nasty curb rash, I was thinking of picking up some nice aftermarket wheels from Powerwheels Pro and moving my street tires over to them at some future point, then pick up some new snow tires and put them on my old rims. I probably couldn't do that if two of my summer tires were extra wide.

Since the tires that normally go on the front end will also fit the rear rims ( my 4 identical snows prove this point), is there any reason not to go with 4 identical summer tires?

Any advice you MB geeks Can offer is appreciated!

Sportstick

First of all...why only a Grand Touring tire? Do you really not want better performance? I would consider the (Ultra High Performance) Michelin Pilot Sport A/S Plus instead...they are much better suited to the car. Or, at the very least, the Pilot Exalto A/S, as a High Performance All Season

You can certainly revert to non-staggered wheels and tires, as some of us do with snow tires. I kept my recently purchased tires which matched the original staggered size, and bought non-staggered wheels only because of a short term inventory shortage of powerwheels pro when I made my purchase. But, the differences are small enough, it works fine. Here is my thread on those wheels.


https://mbworld.org/forums/c-class-w...g-17-reps.html

amazer98

Thanks, sportstick, that was great advice about the Pilot Sport A/S Plus. I checked them out on tire rack and all the MB owners gave them a 10! I'll change my order to those, for sure.

On my other issue, would it be a bad idea to mount 4 standard 225/45R17 tires on my rims, even though the rear rims are wider? Would that stretch out the rear tires so that, were I to re-mount them onto narrower 7.5" wheels, they might be stretched out or distorted? Would they handle weirdly on the 8.5" rear wheels, as opposed to the 245/40R17 tires that would normally go on those wheels?

My motivation is to 1)extend the life of the tires by being able to rotate them, and 2)have the flexibility to get affordable new standard-size rims and put my summer tires on them.

Any thoughts?

Sportstick

I don't know about the long term effect of switching tires onto different size wheels, but to satisfy yourself with what does fit where, use this link:

http://www.1010tires.com/TireSizeCal...?action=submit

You can enter different tire sizes and see what size rim widths are within the range which will fit.

amazer98

Interesting... Your resource says that those narrower front tires will fit on rims 7-8.5" wide, so they will fit. I wonder if, as the tires expand to fit the wider rims, they will end up having a significantly different circumference from the front one?

Maybe I should play it safe and get wider tires in the back? Then again, all the snows are they same size, right? But maybe that was a mistake the tire shop made?

Sportstick

Although I have the same size wheels right now at all four corners, I will again match the OE staggered tire size when it is time for new tires. My assumption is that MB specified this for the Sport model based on some improvement in performance, although I have no first hand data to support that. So, the tire rotation concern may not be worth the trade-off.

On snow tires, yes, all four should be the same and as small and narrow a tire as still fits, as the smaller the contact patch in the snow, the higher the psi of downward force and resulting improved traction.

amazer98

Thanks, sportstick. All this is interesting in an obscure way, and unfathomable as a surreal video game!

The manual gives sizes for snow tires for models with same-sized wheels, but only gives sizes (f&r) for all-season tires on mixed wheel models like the c300Sport. This implies that, if you have a Sport model, you have to use same sized wheels if you want tp run snows... And that means buying another set of rims. If I do that, my winter wheels will outshine my summer ones!

Oh, well, there are worse things in life than that! Thanks for your insights... Especially for the Pilot Sport recommendation!

Rogwp

I also have a C300 with staggered wheel sizes. I have dedicated winter tires and wheels that are all the same size, and I intend to rotate them. My summer tires and wheels are staggered sizes and I do not rotate them. I would not rotate staggered wheels even if the tires were the same size, because I do not feel comfortable putting larger wheels on the front. Any thoughts?

kevink2

Unless the prior owner said he rotated the snows, you might want to put a rear snow up front, to be sure it clears on the inside. The combination of 10mm more offset at the rear wheel and 25mm more wheel width, results in the wider wheel rim being 22.5mm more inward, and only 2.5mm more outward. The narrower tire mitigates the tire positioning, but not the wheel rim position.

.

amazer98

Rogwp and Kevink2, you misunderstand me. I also would never put the wider wheels up front. I would roate the summer tires only if I had them remounted onto standard sized wheels. Of course, if I then put snows on the old staggered wheels, I wouldn't be able to rotate those tires.

So, I might as well bite the bullets and put the correctly sized street tires on them.. And see how quick I run through the treads. My early perception is that staggered wheels may well be a profligate move by MB that's not worth the benefit of slightly better grip when cornering.

Sportstick

First and foremost, congratulations on elevating the forum vocabulary; I believe that is the first use of "profligate". However, I am somewhat less cynical in attributing such behavior to the MB engineers, a group I have found typically not given to such extravagance. In creating the two Sport and Luxury models for C Class, I think they tried to implement as many relevant cues as the business case allowed. However, to what degree they were successful depends on the preferences of every individual buyer.

After almost 20,000 miles on my Michelin Sport A/S Plus, tread depth is 8/32 up front and 7/32 on one rear, 6 on the other. I'm guessing 30,000+ miles for the rears before replacement.

amazer98

Well, it's very reassuring to hear you're getting such good mileage without rotating the tires. I hope my experience parallels yours!

I usually put 4 mounted snows on my car for the upcoming New England winter, but maybe I'll wait and see how these handle the early snows before I invest in that. Probably by the winter of 2012, I'll need to use real snows, but I might be able to squeek through this first winters, since the tires will be new...

Sportstick

They were not capable enough when new for a Michigan winter. The problem is not tread depth. The compound freezes and makes the tires hard and slippery.
Blizzaks WS70!!

amazer98

Wow.. interesting.. so "All Season" compounds aren't capable of handling clod weather, even when no snow is present. I know the term All Season is somewhat marketing hyperbole, but I didn't realize that it precluded driving in the cold!

By the way, I've heard that Blizzaks drive great for the first 5K miles, then the soft grippy layer wears off and they drive a lot more mediocre in the snow. Is this true or just an urban myth? (Rural myth?)

Sportstick

"All Season" tires are better than Summer-only tires, but far inferior to winter tires. From my understanding of your area, I would definitely get winter tires ready. Look specifically for "studless" winter tires, unless your area calls for studs. But, so-called "performance" winter tires, such as the LM series from Blizzak seem to strike a "worst of both worlds" compromise just at the time of year when pure cold weather and snow/ice traction overrides high performance driving thrills. The "cold" threshold for making the transition is about 40 degrees F. The only partial exception to all of this are Continental DWS, which are much better than all other all season tires at handling snow, but are criticized for their reduction in steering crispness and control, which is the obvious trade-off of the tread/compound difference. They are still not as good as dedicated winter tires, and don't perform in the dry like Pilot Sport A/S Plus, but recommended when someone absolutely refuses to have a separate set of winter tires.

Snow tires definitely do wear out more quickly than normal. I try to use them only from November to March and do not drive at all aggressively during that time. My experience is that I will get 4 years of winter driving.

kevink2

Sorry I misunderstood you.

To optimize wear, minimize noise, and avoid excessive mounting and dismounting and possible bead damage, I suggest getting non-directional tire sets. This allows cross or side to side rotation for same size tires (depending on front vs rear wear). For staggered wheels, side to side rotation. OEM C300 tires were non-directional, at least in '08.

Tire rotation, at a minimum, should be done at every oil change, and better at every 5-6K miles. We have practiced this, and it's amazing to feel the "feathering" on the outside edge of the front tires (like running your fingers lightly back and forth along a hack saw blade). It gets worse with miles, and starts making road noise. Cross rotated, the feathering wear process reverses, and in a few 1000 miles, the feathering is nutralized and starts reappearing again in the opposite direction.

In your case, I'd look for a pair of oem "front wheels" for your car on ebay, and get the staggered out of your sport. I got a pair of lux take-offs as spairs from a dealer in texas for $60.

I think the extra width wheel/tires in the rear helps hard core handling for rear wheel drive W204's, inspite of the slightly less rear track, but is more of a carry over for the sport 4MATIC models.

kevink2

Well, based on my experience, we disagree, but that's ok. IMHO, the good winter tire has a much better tread compound for interfacing snow and ice and not loading up with snow, and a better tread pattern loaded with sipes to grip ice. Of course some cold & dry condition stopping distance tests would change my mind, but again that is an extreme case ... 10/10th's.

We still have OEM Michelins on the C300 4MATIC, and never had any problem with dry traction in 10-20 degF weather. That tire has kept it's soft feel over the years much better than HX MXM4'S on another '04 car, but even that car has no trouble on dry roads in cold conditions. I suspect Michelin improved the compounding on this tire between 04 and 08.

That said, for New England winters (raised in Mass near Norwood "Naawood") , you can't beat a set of proven winter tires to take control over the winter. The Sport does have about a 1/2" lower stance, and stiffer suspension vs the Lux, both not great for hard core winter driving.

.

Sportstick

Actually, I cannot find any issue where we disagree! I was merely stating that good tread depth alone (such as on a new tire) does not make an all season tire capable on snow/ice, once the compound freezes. Cold and dry is manageable, as you experienced. The benefits of a winter tire are superior tread and compound, also as you said.

amazer98

Hey, I just got a set of Bridgestone Potenzas mounted on my c300 and can't figure out why they're so noisy and squeal on corners when I exceed 20 mph...

Just kidding, Sportstick! I took your advice and put on four Pilot Sport A/S Plus tires and just drove home from the dealer with a brief detour on the highway. The ride is unbelievable! Whisper quiet, supple feedback from the road, and the car feels like it's riding on rails!

I am very happy with these tires, as I was hoping to be considering each of them cost in excess of $200. Plus, the 4 tires were a total of about $55 less than the MXM4's I was initially considering-- not a fortune, but it's nice to save a few bucks anyway.

Thanks for the tip!

Sportstick

Glad it worked out and you're quite welcome! Enjoy!