okay this might be stupid. but then again it might not so. can anybody explain teh numbers seen on tires, (#/#/#), also what does the oil numbers mean (10W30) (i know its the weight of the oil but be more clear)

i never really tried to find out. so i need to know now

__________________
198? 300D ???K - Future DD
1989 300TE 285K - traded in '12
1984 300SD 186K - Sold in 08
1978 300SD 330K - Died in 05

Tire Numbers:

The numbers in the tire size refer to its width, aspect ratio, and wheel diameter. "205/55R16" means the tire is 205 mm wide, has an aspect ratio (that is, the height divided by the width) of 55%, and fits on a 16" rim.

"R" means radial tire. They're all radials nowadays. Speed ratings are usually inserted before the "R." The most common speed ratings are HR (good for 130mph), VR (149 mph), and ZR (more than 149 mph).

Oil numbers:

Oil weight, or viscosity, refers to how thick or thin the oil is. The temperature requirements set for oil by the Society of Automotive Engineers (SAE) is 0 degrees F (low) and 210 degrees F (high).

Oils meeting the SAE's low temperature requirements have a "W" after the viscosity rating (example: 10W), and oils that meet the high ratings have no letter (example SAE 30). An oil is rated for viscosity by heating it to a specified temperature, and then allowing it to flow out of a specifically sized hole. Its viscosity rating is determined by the length of time it takes to flow out of the hole. If it flows quickly, it gets a low rating. If it flows slowly, it gets a high rating.

Also, in regards to speed rating; while you may never drive 130MPH you may very well still need an H rated tire, or greater. Why if you don't drive fast? Due to the weight of the car.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

so 5w30 oil will operate at a lower temperature than a 10w30 oil? and does that mean that a lower number before the "W" means that it is thinner?

also what does the number after the "W" mean?

also for certain brands, like Rotella T, i only see it in 10W30. do they make other weights for that brand?

thanks for taking the time to educate me.

my dad once taught me but i forgot. in Alaska we did an experiment when the temp was about -40 outside. we put several oils in a jar and see how they turned out. some turned i'd like to say solid until you poke it. fully synthetic had some goo in its texture too.

__________________
198? 300D ???K - Future DD
1989 300TE 285K - traded in '12
1984 300SD 186K - Sold in 08
1978 300SD 330K - Died in 05

10W30 ist not suitable to use under normal driving conditions. The high temperature range is to low.

I would recommend a 10 W 40 or 15 W 40 for normal climatic conditions. A 5 W 50 for Alaska.

A table with the correct engine oil specs you will find in the manual.

Also take into consideration: If your engine has been run on non synthetic oil and has had neglected oil change intervals, you might find some sludge in the engine. A synthetic oil with lots of detergents might cause problems when the whole sludge is diluted and carried into the filter. Better stay close to the oil quality which had been used before and shorten the changing intervalls. Also stay away from any engine cleaning stuff.

There are far more engines which had been killed by high detergent oil or engine flush than had been killed when used with normal quality oil and the recommended changing intervall.

Kind regards
Eberhard