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Tyre Topic Index

Posted: Wed Apr 29, 2009 7:16 pm
by -Scott-

Posted: Fri Jun 05, 2009 9:15 am
by chimpboy
Various info culled from around the internet that might be helpful to some, of course it's common knowledge to many who've been around a while. Please move this if I shouldn't have put it here.

Tyre dimensions terminology:

Image

Load ratings (on commercial tyres):

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LI 	kg 	 LI 	 kg 	LI 	kg 	 LI 	 kg 	 LI 	 kg
50 	190 	65 	290 	80 	450 	95 	 690 	110 	1060
51 	195 	66 	300 	81 	462 	96 	 710 	111 	1090
52 	200 	67 	307 	82 	475 	97 	 730 	112 	1120
53 	206 	68 	315 	83 	487 	98 	 750 	113 	1150
54 	212 	69 	325 	84 	500 	99 	 775 	114 	1180
55 	218 	70 	335 	85 	515 	100 	800 	115 	1215
56 	224 	71 	345 	86 	530 	101 	825 	116 	1250
57 	230 	72 	355 	87 	545 	102 	850 	117 	1285
58 	236 	73 	365 	88 	560 	103 	875 	118 	1320
59 	243 	74 	375 	89 	580 	104 	900 	119 	1360
60 	250 	75 	387 	90 	600 	105 	925 	120 	1400
61 	257 	76 	400 	91 	615 	106 	950 	121 	1450
62 	265 	77 	412 	92 	630 	107 	975 	122 	1500
63 	272 	78 	425 	93 	650 	108 	1000 	123 	1550
64 	280 	79 	437 	94 	670 	109 	1030 	124 	1600
Speed symbols:

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SSY  	Maximum Speed for Passenger Tyres
M 	81mph 	 130km/h
P 	93mph 	 150km/h
Q 	99mph 	 160km/h
R 	106mph 	170km/h
S 	112mph 	180km/h
T 	118mph 	190km/h
H 	130mph 	210km/h
V 	150mph 	240km/h
W 	169mph 	270km/h
Y 	187mph 	300km/h
ZR 	>150mph 	>240km/h
Sidewall markings:

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eg. 205/55 R15 87V

205 - Nominal Section-width in mm.
55 - Aspect ratio (Tyre height is 55% of tyre width).
R - Means it's a radial tyre.
15 - Rim diameter Code (in inches).
87 - Load Index. Maximum load of this tyre
V - Speed Symbol. Indicating maximum speed.

TWI
TWI = Tread Wear Indicator. Cross ribs evenly spaced around the circumference of the tyre in the longitudinal tread grooves and becoming exposed when the remaining tread depth is down to 1.6mm.

DOT
DOT = Department of Transportation, USA.

026504
Approval number acc. to ECE regulation 30.

TUBELESS
Tubeless. TUBE TYPE tyres must be mounted with tubes.

(E)4
All passenger car tyres from current production comply with ECE Standard 30. All tyres are marked with a circle containing an E and the number of country of homologation. A multi digit homologation number follows this marking.

E.g. (4=Netherlands)

1607 (after the DOT number)
Date Code - this code comprises 4 digits, i.e. the first 2 digits for the week and the second 2 digits for the year (so "1607" means the 16th week of 2007.) For tyres produced in the 1990s, the date code is three digits plus a triangle ie "207<" (where the "<" is a triangle) means the tyre was manufactured in the 20th week of 1997. 
There are many tyre size calculators out there to help with the mm/inch and aspect ratio issues. Heck metric tyres still incorporate an inch measurement for the nominal rim size.

Some good calculators are:

http://www.1010tires.com/tiresizecalculator.asp (this one has all the odd sizes like 10R15 built in as well).

http://www.exploroz.com/Vehicle/Tyres/SizeCalc.aspx

http://www.etyres.co.uk/tyre-size-calculator.htm (compare two metric sizes)

Posted: Sun Jun 07, 2009 11:26 am
by 80's_delirious
Why not make this a sticky at the top of Gen Tech so it is more visible?

Posted: Sun Jun 07, 2009 1:50 pm
by -Scott-
Stickies don't get read.

If somebody actually reads the stickies, they'll read the Bible, and should find this thread anyway.

Posted: Fri Jun 12, 2009 9:08 pm
by bogged
-Scott- wrote:Stickies don't get read.

If somebody actually reads the stickies, they'll read the Bible, and should find this thread anyway.
I'd rename the bible to FAQ page or something that gives them the idea what its about...

Posted: Sat Jun 13, 2009 9:26 am
by grimbo
I still reckon the only way to get people to red these is to call them Free P0rn or the like

Posted: Sun Jul 19, 2009 7:40 pm
by mike_nofx

Posted: Sun Jul 19, 2009 7:45 pm
by -Scott-