tire rating

[n/a]

I have read about as much as I can about the different tire sizes and I have decided on 205/70/14 on some alloys I have acquired.  The tire stores have indicated that the correct rating for the 280 SL is H which restricts the options to only two brands that I have found on tire rack, one if you only consider all season.  I am looking more for comfort than performance; are there any opinions on S & T rated tires?

[gugel]

I've put T-speed rated Bridgestone Turanza 205/70-14 LS-T blackwalls on my 230SL and am quite happy with them, for both ride and handling.  Gernold once mentioned to me that he thinks today's S and T rated tires are probably better and safer than H rated tires were in the 60's and 70's.  FWIW, the last I heard he was equipping his 113's with Michelin X 195/75-14 S-rated tires.  

However, there are some members of this list who drive 125 mph for extended periods regularly, who have said they won't use anything less than H-rated tires.  You might want to look at these two earlier threads on tires:

http://sl113.org/forums/index.php?topic=2880
http://sl113.org/forums/index.php?topic=2085

Chris Earnest

[mdsalemi]

Just out of curiosity, are there really any members who drive "extended periods" at 125 MPH?  Unless they are in Montana, I'd be curious as to where this occurs--

1)  In most of the USA, this will land you into jail, and the $1,000 AAA bail bond probably won't cover your release! You might, however, end up on COPS or at least, FOX news.  I know, how cool would that be with that chic Pagoda?

2)  Is there really any place short of a few stretches of desolate interstate out west (hence the Montana reference)where you could do this?

3)  If I'm not mistaken, isn't 125 mph or something like this a bit of a thing of the past on the autobahns?  I hear congestion is rampant and all but a few stretches have some kind of limits now--if not posted limits, then practical limits by traffic.

Last time I was in Germany a few years ago, doing 30 mph in a jam near Frankfurt and Stuttgart (and Munich and Bonn and Koln and Dusseldorf...et al) was pretty standard--the wide open speeds the I remember in the 1970's seem to have disappeared.  Doing 140kph was possible only at certain times between cities.

Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[n/a]

Thanks for the input.  In my discussions with "tire experts", their focus was more on the stiffness and structure of the sidewall not just for the absolute speed.  One store said they would not sell me less than an H rating because that's what the car required and anything else would be too weak?

[Mike Hughes]

That tire store policy is commonly encountered and is designed to limit the store's iliability after a customer wrecks a car with the "wrong" tires fitted that were sold and installed by that store.  The main issue with lower versus higher speed tire ratings is that the higher speed-rated tires generally have a stronger (and therefore slightly stiffer) sidewall to help counteract higher speed centrifugal forces that can alter tire profile and rolling diameter. A lower speed-rated tire with a more flexible side-wall may cause the car to handle a little more "squirrely" in turns or in "stress maneuvers," which may be a little disconcerting, if not flat out dangerous! I once replaced the now $300+ "H" rated Pirellis on my XJ-6 with unrated Goodyears at less than half the price, reasoning that a car rarely driven above 70 mph does not need high-speed tires. This immediately transformed a superb tracking and handling car into a "wandering pig!"



- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havanna Brown (408)
  Light Beige (181)
  Cream M-B Tex (121)

[gugel]

quote:Originally posted by mdsalemi

Just out of curiosity, are there really any members who drive "extended periods" at 125 MPH?  Unless they are in Montana, I'd be curious as to where this occurs--
...
3)  If I'm not mistaken, isn't 125 mph or something like this a bit of a thing of the past on the autobahns?  I hear congestion is rampant and all but a few stretches have some kind of limits now--if not posted limits, then practical limits by traffic.

Michael, I share your skepticism about whether any members really drive that fast for extended periods, but in earlier threads, at least a couple of members claimed they did, and for that reason wouldn't use anything but H-rated tires.  As for Autobahn speeds -- when I was in Germany a year ago, there were are number of cars going well over 125 mph when they could -- for example, on the stretch between Munich and Passau and even between Munich and the Bodensee.  Traffic is indeed much worse than it used to be, but drivers still go very fast when they can -- in fact, faster than they used to, IMO, probably because cars, tires, and brakes are better.

quote:Originally posted by Mike Hughes

The main issue with lower versus higher speed tire ratings is that the higher speed-rated tires generally have a stronger (and therefore slightly stiffer) sidewall to help counteract higher speed centrifugal forces that can alter tire profile and rolling diameter.

Mike, isn't the chief factor in assigning speed ratings the ability to safely handle the higher temperatures built up by higher speeds?  It's certainly true that with a stiffer sidewall there would be less flex, hence less heat buildup, and presumably better handling, but one could postulate a stiffer tire which still couldn't safely handle the temperatures generated by high speeds, so wouldn't be given a high speed rating.

Chris

[Bob G ✝︎]

Not critisize your selection of tire size for your SL. but you are adding more weight to the suspension which in turn does not give the full capabilityof the suspension to handle like Rudy designed it too. I think for boulevard cruising there is nothing like a wide track tire. but for shere motoring experience the way this car was designed for a 185 HR 14 80 radious tire will give you all the right feeling and response with a flick of the wheel should you ever need to use the capabilities of the suspension on your SL , not forgetting how nimble they are to parell park. So sweet you think some one picked the car up put it in the space for you.


Bob Geco

[71 pagoda]

I too put the bridgestone turanza  205's on my 71.  The difference in handling and ride is much better than the 185.  Do not use a 205 for a spare as the trunk will not close correctly.

[Vince Canepa]

For Michael - Hwy. 1 between Santa Cruz and Half Moon Bay (in California) is still a great place to run extended periods at speeds up to the maximum our cars can attain.  There are plenty of other parts of the country that are wide open and and relatively free of law enforcement.  Having said that, I now live in Virgina, one of the worst states.  I do have my spots, but they are quite a drive before I can have my fun.

For Bob - Modern materials actually make the 205 about the same weight or lighter than the old 185.

For all - The higher the rating, the higher the performance intent of the tire designers.  That corresponds to more precise handling, more responsive steering, maybe a slighly harsher ride.  Some of us actually consider our cars "sports cars" and treated them as such, including the tires we select.  Some folks consider the cars stylish cruisers and make their decisions based on that.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[Mike Hughes]

quote:Originally posted by gugelMike, isn't the chief factor in assigning speed ratings the ability to safely handle the higher temperatures built up by higher speeds?  It's certainly true that with a stiffer sidewall there would be less flex, hence less heat buildup, and presumably better handling, but one could postulate a stiffer tire which still couldn't safely handle the temperatures generated by high speeds, so wouldn't be given a high speed rating.

Chris

The heat stress generated at higher speeds is partially due to the stretching and squirming of the tire carcass due to the centrifugal forces  encountered at higher rotational speeds.  A stiffer carcass lessens the heat stress imposed by these forces, but you are absolutely right that rubber compounds formulated to deal with the stressed imposed by higher rotational speeds are also part of the whole package.

- Mike Hughes  -ô¿ô-
  1966 230SL Auto P/S
  Havanna Brown (408)
  Light Beige (181)
  Cream M-B Tex (121)