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Tires

This component is part of Wheels and Tires.


The manufacturer code

A word on tire safety to start

Many of us will buy our cars with older tires on them. Few will think to check the age of the tire or even know how to check tire age. The good news is that the information you require to be able to tell when your tire was manufactured is printed on the tire wall.

The format is 4 digits, which breakdown as follows:

  • the first two digits are the week of the year,
  • the second two digits are the last two digits of the year

For example: 4101 written on the tyre wall means that the tyre was manufactured in the 41st week of 2001.

There is no shelf life for tires so you'll have to make your own decision about what's safe and what should probably be replaced. However, it is recommended that you watch this short clip, which provides the sort of information one might like to be armed with in order to make a more informed decision:

http://abcnews.go.com/Video/playerIndex?id=4826897


Here is a different look of the tire information and how to determine the date it was manufactured.


Definition

The tire (German: Reife) is the important rubber component that keeps your car driving.

The Pagoda's were originally only shipped with 185x14 tires of:

  • Continental Radial
  • Firestone Phoenix P110 cord-belted radial

This is a picture of a never-used, original spare tire with the original colour stripes on the tread.

These tires have a rubber strip or rim on the outside, which is meant to protect the hub-caps from damage when hitting the curb.

When these tires were originally made there were no variations on the Aspect Ratio (see below). In those days all tires had the same sidewall height to tread width ratio, 80 for European tires and 78 for US sourced tires. Someone measured an original Continental 185SR14 and measured its rolling circumference as 2040mm or an aspect ratio of 79 3/4". Choosing a correct tire size will ensure that the speedometer and odometer on the car are accurate. Also see Tire Sizes for acceptable tire sizes for our cars.

Because many Pagoda's were delivered in the US, where whitewall tires were in fashion at the time, many people have an image of a Pagoda with a whitewall tire. In Europe whitewall tires were never popular and currently it is considered a matter of taste whether whitewall tires suit the car or not. Certainly a European specced car (headlights, no side-markers) looks cleaner with just a black tire.

Function

Tires keep the car on the road and have a very large effect on the handling of the car. This can be summed up in one quote from Laurence Meredith in his book, "Essential Mercedes SL":

The role played by the newly invented Halbgurtel (half-belted) Continental RA60 radial tires cannot be over-emphasized. These tires had specially constructed sidewalls to ensure that they remained 'stiff' and as near to the vertical plane as possible under hard cornering. Early Michelin X radials had proved to be far too flexible when fitted to high performance sports cars like the 300SL, and tended to distort circumferentially during hard acceleration and deceleration, in much the same way as the enormous tires fitted to the back of drag racing machines. Because the cords used in the construction of the Continental RA60s were wound at an angle below the outer tread, they were not true radials in the modern sense but they certainly made for an acceptable compromise in considerations such as ride comfort and roadhandling. (N.B. The Conti RA60 and Firestone Phoenix were very similar tires and OEM on the 113's).

Also see: http://www.sl113.org/forums/index.php?topic=2168

Tire Markings

Tires are marked with tire code or rating. Typically the code is something like P205/75 V R14. This code means the following:

P
Tire Type. The letter P indicates that the tire is designed for a passenger vehicle, such as a car. Other possible tire designations are T for temporary, for for example a space saver tire, or C for commercial vehicles such as large trucks.
205
Section width. This indicates the width of the tire in millimeters, measured at its widest point.Typically ranges from 145 to 315. The higher the number, the larger (wider) the tire.
75
Aspect ratio. It is the relationship between the cross sectional height and the section width. 75 means that this tire's height is 75% of its width. Other common aspect ratios are 50, 60, 65, 70, 75, and 80. The higher the aspect ratio, the taller the tire. Low aspect ratios provide more traction, whilst high aspect ratios give better mileage.
V
Speed rating. This letter, ranging from B (31 mph or 50 km/h) to Z (over 149mph or 240 km/h) indicates the maximum speed at which the tire can be operated. See table below. For a Pagoda a H rating should be sufficient.
R
Radial ply construction. Almost all tires used today are Radials. The old designation B is for Bias ply tires, or D for Diagonal tires.
14
Rim diameter. The Rim diameter in inches. Modern rims range from 12 to 17 inches. Pagoda's typically have 14" rims, although some people have tested with 15" rims.

Sometimes other numbers and markings are added (e.g. M+S for mud and snow or winter tires) but these are typically manufacturer specific.

Also see Tire Sizes for acceptable tire sizes for our cars.

Tire Speed Ratings

Codekm/hmph
N14087
P15093
Q16099
R170106
S180112
T190118
H210130
V240149
W270168
Y300186
ZR>240>190

Tire load ratings

LoadIndexWeight permitted per tire, kg
91615
92630
93650
94670
95690
96710
97730
98750
99775
100800
101825
102850
103875

Popular tires available for Pagoda's


Phoenix tire on a car

Note: Michelin and other manufacturers offer different types of tire in different parts of the world. In Europe the Michelin MXV-P and Vredestein Sprint Classic are both available and are specialised tires for classic cars at the original size of 185R14 (equivalent to 185/80R14), with the correct rubbing strip. In the US these tires may be harder to get hold of, but Coker offers the Phoenix as a classic tire. Look for these tires first, before trying out alternatives.


ManufacturerDesignationManufacturer linkRubbing stripComments from usersPricing (2007)
MichelinMXV-P 185 HR 14http://www.michelin-passion.com/yesVery positive feedback received. Good handling on fast and twisty roads. Accurate reading of the speedometer. Mercedes-Benz Partnumber: Q 440 5185>255 each
VredesteinSprint Classic 185HR14http://www.vredestein.com/yesMany users report very good performance and excellent looks with this tire.120
Phoenix185R14 3/4" whitewall tirehttp://store.coker.com/yesClassic whitewall look, the most original appearing tire, ride reputedly not the best.$206
MichelinXDX 205/70R14http://www.michelin.com/ or http://store.coker.com/noAlloys (6.5" width, 126 part # wheels), a wider look with positive feedback$225
Michelin185 TR/14 Rainforce MX4http://www.michelin.com/ or http://store.coker.com/noCheaper alternative, dependable blackwall tire$75
MichelinXD-T 195/75R14http://www.michelin.com/ or http://store.coker.com/noperfect on 5.5 or 6" rims$ ??
Pirelli205/70 SP4E noPostive feedback on ride and handling reported.$100 per tire
Pirelli205/70 P4000 noMixed feedback on ride (lack of stickiness) and handling reported. 

The common feeling is that cheaper tires (say under $70) do not do these cars justice because of the high rigidity in the side-wall required. High performance tires are needed.

Some have experimented with van tires with a high load index, on the premise that in order to endure more weight, a high load index tire has stiffer sidewalls. The tire used was a Semperit Van Life 185R14, a van tire for a small German vans on the wheelbase of a subcompact car. Advantage: Easy to get, cheap ($64 apiece), and with a load index of 102 (850 kg). Semperit is owned by Continental. The happy owner says: "The car handles like it has power steering (which it has not), and I have the feeling there is no rolling resistance whatsoever".

Note: tiresizes of 205/70 for the spare tire in the trunk may be too wide. The trunk hinge can press on it, and require a hard push on the trunk lid to get it latched. This can cause permanent creases on the spare tire cover.

Maintenance

Tire Pressure

Here is the label in the trunk of a 1966 230SL (US version):

There are different versions of this tag depending on car model, original tire brands, and perhaps for USA and European models.

Some decals in the trunk list 26 psi front (1.8 atm), 32 psi rear (2.2 atm).

The trunk label says 26 front, 32 rear, but the owners manual refers to the label on the trunk lid and states "should other tires evenually be installed, for example radial tires, the tire pressure will be other than that specified on the chart. Please consult your MB dealer". It then shows a cross section of a properly inflated tire in which the treads are contacting the road evenly. An overinflated tire has a convex profile and an underinflated tire has a concave profile where it meets the road (cross section).

Many people run at higher pressures nowadays, with more modern tires. Ranges of 30-32 psi for both front and rear are regularly mentioned.

Wear and tear

Tires, even when they have lots of tread-depth left, worsen with age. Especially since our Pagoda's do not cover many miles per year anymore, tires will deteriorate with age before they wear out.

Symptoms that might indicate your tires need replacing:

  • lack of stickiness or adhesiveness to the road even though there is sufficient treaddepth
  • vibration due to beginning tread separation
  • vibration in steering or drivetrain (the internal structure may be affected)
  • cracks in the sidewall

If a tire destructs at highway speed, the best possible outcome would be body damage around the wheel well. The cost of repair will far surpass the cost of a set of tires. The additional benefit will be the improved ride with the new tires.


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