Upsizing tires on a diesel - Page 2 - PeachParts Mercedes-Benz Forum

Brian Carlton · #16 01-06-2005, 10:43 PM

Quote:

Originally Posted by boneheaddoctor

exactly how fast do you think one of these will go.........

Z rated tires are without a doubt serious overkill.

BHD, there are a multitude of speed ratings other than "Z".

In the case of the SDL, the minimum recommended rating is "H" for 130 mph.

Since I do not believe that I will be approaching that speed any time soon, I much preferred to purchase the Michelin Hydroedge tires with a "T" rating. Cannot exceed 118 mph with these tires. Like I would anyway.

BTW, who is that guy beating the crap out of?

Must be a liberal

SHARK1007 · #17 01-06-2005, 10:54 PM

Brian, that's one of my issues, I don't want to be held back to 118mph, lotsa times I'm in a real hurry.

Brian Carlton · #18 01-06-2005, 10:57 PM

..........would be the preferred choice.

SHARK1007 · #19 01-06-2005, 11:11 PM

Does a 617.950 have enough torque to spin that blade?

Brian Carlton · #20 01-06-2005, 11:18 PM

You just need a big Holset turbo, a giant intercooler, and a heavily modified IP and you're all set.

phidauex · #21 01-07-2005, 01:40 AM

Like with many things, you need to understand why the speed rating exists.. They don't mean, "If you drive 1 MPH over this limit your tires will immediately explode." they mean, "This tire has been constructed using techniques and materials that make it appropriate for higher speeds than these other tires, and lower speeds than these other tires." Those materials and construction also affect the rest of the tire, and things like sidewall flex. A heavier car needs a higher speed rating, because speed rating is really just another way to say 'durability rating'. I probably wouldn't put a T rated tire on a heavy 123. Not because I'll be exceeding its speed limitations, but because T rated tires aren't as strong as H rated, and a heavy car exerts a lot of sideways forces on the tire, and I want them to hold up.

Anyway, just tired of the misconception that if you aren't exceeding a given speed that you don't need that highly rated of a tire. If you want a more complete answer, talk to Luke about it.

Back to the topic... I've got wheels off a CLK on my 300TD, they are the 5 spoke, and are wearing the CLK's stock rubber, 205/55/16H's. They are good tires, even in their worn and 'ready to be replaced' state. They are a little wider, but seem to handle very well. The diameter is the same though, they are something like 99.5% the circumference of the stock tires. However, the tierods are almost touching the wheel. I mean reeaally close. So close that you have to use the stick-on wheel weights for balancing instead of the clip-on, because the clip on ones would hit the tie rod! But, it works, handles well, and looks really sharp.

peace,
sam

TonyD · #22 01-07-2005, 06:37 AM

On Tirerack, I couldn't find any H-rated or better tires in 205/70-14. There are a bunch available in H and V in 195/70-14.

I've been at 120 (according to a handheld GPS) in my car before I bought it, with the previous owner driving.

boneheaddoctor · #23 01-07-2005, 07:41 AM

Quote:

Originally Posted by Brian Carlton

BHD, there are a multitude of speed ratings other than "Z".

In the case of the SDL, the minimum recommended rating is "H" for 130 mph.

Since I do not believe that I will be approaching that speed any time soon, I much preferred to purchase the Michelin Hydroedge tires with a "T" rating. Cannot exceed 118 mph with these tires. Like I would anyway.

BTW, who is that guy beating the crap out of?

Must be a liberal

Well on the tire issues I have known people who absolutely had to get the biggest and best.....and paid for it even if their car was incapible of it and was unlikely to even see triple digit speeds.....

I buy from wet and dry traction ratings along with hydroplaning resistance.....and read the reviews of said tires to see what people who used them actually thought.

My car has seen triple digit speeds once.....and may never again....can't afford to get busted at those speeds......

The avatar?.....of course its a conservative knocking sense into a thick headed liberal.........

Brian Carlton · #24 01-07-2005, 09:32 AM

Quote:

Originally Posted by phidauex

A heavier car needs a higher speed rating, because speed rating is really just another way to say 'durability rating'. I probably wouldn't put a T rated tire on a heavy 123. Not because I'll be exceeding its speed limitations, but because T rated tires aren't as strong as H rated, and a heavy car exerts a lot of sideways forces on the tire, and I want them to hold up.

This may be the case for specific vehicles driven a certain way. However, Michelin makes this T rated Hydro-Edge tire in a 215-65-15 size for a reason. They do not intend to put it on vehicles that weigh 2800 lbs. Clearly it is manufactured for large and heavy sedans. I have put it on the heavier SDL with no ill effects. However, I drive the SDL with minimal sidewall flex.

The tires are guaranteed for 80,000 miles. If that is not durability, I'm not sure what is.

boneheaddoctor · #25 01-07-2005, 10:01 AM

Quote:

Originally Posted by phidauex

Like with many things, you need to understand why the speed rating exists.. They don't mean, "If you drive 1 MPH over this limit your tires will immediately explode." they mean, "This tire has been constructed using techniques and materials that make it appropriate for higher speeds than these other tires, and lower speeds than these other tires." Those materials and construction also affect the rest of the tire, and things like sidewall flex. A heavier car needs a higher speed rating, because speed rating is really just another way to say 'durability rating'. I probably wouldn't put a T rated tire on a heavy 123. Not because I'll be exceeding its speed limitations, but because T rated tires aren't as strong as H rated, and a heavy car exerts a lot of sideways forces on the tire, and I want them to hold up.

Anyway, just tired of the misconception that if you aren't exceeding a given speed that you don't need that highly rated of a tire. If you want a more complete answer, talk to Luke about it.

Back to the topic... I've got wheels off a CLK on my 300TD, they are the 5 spoke, and are wearing the CLK's stock rubber, 205/55/16H's. They are good tires, even in their worn and 'ready to be replaced' state. They are a little wider, but seem to handle very well. The diameter is the same though, they are something like 99.5% the circumference of the stock tires. However, the tierods are almost touching the wheel. I mean reeaally close. So close that you have to use the stick-on wheel weights for balancing instead of the clip-on, because the clip on ones would hit the tie rod! But, it works, handles well, and looks really sharp.

peace,
sam

Tires carry a load rating for the purpose of knowing they can handle the weight......

Speed rationg has everything to do with how many rpms the design and materials of the tire can wistand. before overheating and failure occurs.......It has nothing to do with cornering capacity at all.

phidauex · #26 01-07-2005, 11:51 AM

Some of these issues (relating to speed ratings) are discussed in more detail in this other thread:

Mercedes Approved Tires

peace,
sam

Brian Carlton · #27 01-07-2005, 12:09 PM

I read the other thread and I had to get a good laugh out of this statement:

"While I understand/appreciate the minimum "H" rating, how come my owners manual (1986 560 SEL) recommends that I use "T" rated winter tires?"

Now, here is a V8 powered large sedan that will get along fine on "T" rated winter tires. The vehicle is easily capable of the 118 mph maximum speed rating of the "T" rated tire.

But, I cannot put the "T" rated tire on my 300 SDL??

Get a grip on reality. Larry Bible has it right on the money.

boneheaddoctor · #28 01-07-2005, 12:21 PM

I would worry about somebody who would drive 118+ mph on winter tires........

Hatterasguy · #29 01-07-2005, 05:21 PM

When I was pricing out tires for my SDL last spring no shop would put less than H rated tires on it. Costco, Firestone, Town Fair, Sears, and an Indy told me they wouldn't do it; they flat out told me no. I ended up with Z rated summer tires, they didn't offer H in the size I needed.

W126's love wider tires, I am running 225's on 7.5in wide wheels, these are as wide as you can go without spacers. They have tons of grip and I cannot break them lose. Also the shed water like crazy, I love the wet traction. Larger better tires beat the stock ones in every catagory in my book.

Brian Carlton · #30 01-07-2005, 05:51 PM

Quote:

Originally Posted by Hatterasguy

When I was pricing out tires for my SDL last spring no shop would put less than H rated tires on it. Costco, Firestone, Town Fair, Sears, and an Indy told me they wouldn't do it; they flat out told me no. I ended up with Z rated summer tires, they didn't offer H in the size I needed.

I had absolutely no issues. I took advantage of the $50.00 Michelin rebate and had my indy get four Hydroedge tires for a grand total of $410. out the door (after rebate).

I'll bet these T rated tires (directional) will easily outperform any H rated tire in rain. In addition, the ride is probably smoother that the H or Z rated tires.