."\ tyre.1 .TH TYRE P "Manual V1.0 for Program V1.0 1998.10.21" "Julian Stacey" "Julian Stacey, Vector Systems Ltd" .\" A4 the cludgy way. .pl 29.6c .UC 4 .SH NAME tyre \- Determine outer size of a car tyre in millimetres. .SH SYNTAX .B tyre .SH SUMMARY .I tyre Tiny program to determine outer size (width + 2 x diameter of a car tyre in millimetres. .SH DESCRIPTION When you buy new snow chains for your car tyres, you have to find ones that will fit. Chains if bought new, should have a label quoting several sets of tyre geometries it will fit. If your wheels are of an unusual size, you may not find them in the chain manufacturer's list of common sizes, but maybe chains might fit anyway ? Maybe you have unlabelled chains from another car, know they used to fit a particular wheel size, & want to know if there's a chance they might fit your new wheel size ? But you don't want to get cold oily rusty filthy trying chains on, if no chance they will fit ? So use this tiny programme to do the geommetry first. Tyre Manufacturer number triplets do Not give outside diameter, but use a brain dead combination of Metric millimetres And Imperial Inches. This program calculates geometry to help you. What may interest you most is trading a bit off the tread width for a bit on the outside diameter, or vice versa.) WARNINGS / DISCLAIMERS .in +2 The code or description may not match reality. Code may not match the description. (Read the code, tell me if I got something wrong). If you don't understand, do Not use this programme. I disclaimer all & every liability, go elsewhere to get certification, Use your common sense ! Many jurisdictions doubtless only allow you to use chains that match "officially" Do Not assume chains will fit properly just because numbers are similar (After all, some set of summer tyre numbers would produce a match for some winter tyres, but if you put the chains on a low profile summer tyre with aluminium hubs, it would abrade the aluminium, & maybe catch & snap). Loose chains might not grip tyre well enough, causing loss of traction downhill & up, & damage to rubber if going up a steep hill, tyres slipping in chains. Loose chains can flap, catch on the car, dmage, snap, wrap round axle or brake pipes, use your imagination & common sense. .in -2 Consider a theoretical single piece of chain stretched from axle, out round the tyre & back to axle: Each extra 1cm of radius takes 2cm of chain otherwise available for tread width: so 2 * radius + width might be a meaningful equivalent for matching triplets. For each extra 1cm of radius on each side (ie 2cm), you will also need 2 * 3.14 * 1cm of extra circumferential chain. Further consider that the average chain around the circumference is some approximation between a set of squares on the centre of a tyre, & a diamond lattice around the curved edge of tyre. So as the circumference of the tyre grows, if we assume a 45 degrees diamond each extra 1 cm of circumference pull on the diamond around the circumference deprives each of 2 side walls of 1cm of chain. However, its a cross between a diamond & a square, so halve the effect, assume 1 cm of increased circumference takes not 2 but just 1 extra cm of sidewall chain. What you need are chains with (A) about the same circumference = 3.14 * Diameter, & (B) An addition of width + 2 * radius that match yours. (because every extra 1 cm. of radius use 2 cm. of chain across the tread). So this program emits 2 numbers: Circumference & Diameter+Width. .ft B Some tyre examples: .ft R .in +4 .nf \" { A B C D E F .\"---------------------------------------------------------------------------- 175 70 R 13 82 H : Summer Tyre, Old Car. Same geometry for both. .\"---------------------------------------------------------------------------- 175 70 R 13 82 T : Winter Tyre, Old Car. Same geometry for both. .\"============================================================================ .\" New Car: Subaru Trend Fahrzeugschein: 29.07.1998 .\" 195/60R15 87V .\" 205/50R16 87V .\"---------------------------------------------------------------------------- 205 50 R 16 87 V : Summer Tyre, New Car. .\" Bridgestone Potenza RE030, EP 3V, DCB517, .\" Made In Japan, T9701 E030 Z, .\" Tubeless, Steel belt radial, E4, 020647, (Tread) 008 .\" Sold on new Japanese large limousines .\" Bridgestone: A Manufacturer .\" Potenza: A brand name of manufacturer. .\" RE 030: Tread type. .\"---------------------------------------------------------------------------- 205 50 ZR 16 87 W UniRoyal Rain Sport2 : New Summer Tyre, New Car. \" Tyres bought 09.07.2008 .\"---------------------------------------------------------------------------- 195 60 R 15 88 H M+S : Winter Tyre, New Car \" Looked at 2009_01_08 (V profile) .\" Continental Winter Contact, 195/60R15RAD, 88H, M+S Tubeless, .\" E4 026940, Max Load 560Kg 1235 lbs, .\" Max Pressure 300KPI 44PSI (40 with seat beeds ) .\" Tread Ply: 1 Poly + 2 steel + 2 Nylon, Side Ply: 1 poly. .\" ---------- .\" V means 240, H means 210, but Fahrzeugschein box 6 says max 200 Km/hr. .\" So I convinced Dekra I didnt need a 210 sticker on dash board. .\" Fahrzeugschein says: .\" 195/60R15 87V .\" 205/50R16 87V .\"---------------------------------------------------------------------------- .\" Munich vendors: .\" http://www.reifen.com/tire/search.do?directSearch=true&nextStep=5&tirePageno=0&KBASearch=false&sortingId=1&tireTypes=PW%2COW&tireWidth=195&ratio=60&diameter=R16&speedIndexGroupId=&priceCategoryId=&tireMF=&runOnFlatAndReinforcedOptionValid=1&x=0&y=0 .\" http://www.atu.de/pages/shop/reifen/reifen_suche.html .\" http://www.reifen.com/tire/search.do?directSearch=true&nextStep=5&tirePageno=0&KBASearch=false&sortingId=1&tireTypes=PW%2COW&tireWidth=195&ratio=60&diameter=R15&speedIndexGroupId=H&priceCategoryId=&tireMF=&runOnFlatAndReinforcedOptionValid=1&x=0&y=0 .\" Some UK tyre vendors: .\" pit stop .\" http://www.freewayfastfit.co.uk .\" http://www.national.co.uk largest independent fast-fit tyre specialist. .\" http://www.kwik-fit.com .\" http://www.setyres.com .\" http://www.ststyrandexhaust.co.uk .\" http://www.watlingtyres.co.uk .\"---------------------------------------------------------------------------- .\" Manufacturers: .\" http://en.wikipedia.org/wiki/Dunlop_Tyres .\" http://en.wikipedia.org/wiki/Hankook_Tire .\"---------------------------------------------------------------------------- .fi \" } .in -4 Explanation .nf \" { .in +4 A Width of tyre in millimetres B Ratio of Height of rubber tyre, to width of tyre. C Radial: All modern high speed tyres are, (however old & slow tyres may be cross-ply) D Inner diameter in Inches. E Load Index: Maximum Kilograms Per Tyre, .fi \" } .in +2 65:290, \" Source: http://www.kwik-fit.com 66:300, \" Source: http://www.kwik-fit.com 67:307, \" Source: http://www.kwik-fit.com 68:215, \" Source: http://www.kwik-fit.com 69:325, \" Source: http://www.kwik-fit.com 70:335, \" Source: http://www.kwik-fit.com 71:345, \" Source: http://www.kwik-fit.com 72:355, \" Source: http://www.kwik-fit.com 73:365, \" Source: http://www.kwik-fit.com 74:375, \" Source: http://www.kwik-fit.com 75:387, \" Source: http://www.kwik-fit.com 76:400, \" Source: http://www.kwik-fit.com 77:412, \" Source: http://www.kwik-fit.com 78:425, \" Source: http://www.kwik-fit.com 79:437, \" Source: http://www.kwik-fit.com 80:450, \" Source: http://www.kwik-fit.com 81:462, \" Source: http://www.kwik-fit.com 82:475, \" Source: http://www.kwik-fit.com 83:487, \" Source: http://www.kwik-fit.com 84:500, \" Source: http://www.kwik-fit.com 85:515, \" Source: http://www.kwik-fit.com 86:530, \" Source: http://www.kwik-fit.com 87:545, \" Source: http://www.kwik-fit.com 88:560, \" Source: http://www.kwik-fit.com My winter tyres confirm 560Kg 89:580, \" Source: http://www.kwik-fit.com 90:600, \" Source: http://www.kwik-fit.com 91:615, \" Source: http://www.kwik-fit.com 92:630, \" Source: http://www.kwik-fit.com 93:650, \" Source: http://www.kwik-fit.com 94:670, \" Source: http://www.kwik-fit.com Confirmed elsewhere 95:690, \" Source: http://www.kwik-fit.com 96:710, \" Source: http://www.kwik-fit.com 97:730, \" Source: http://www.kwik-fit.com 98:750, \" Source: http://www.kwik-fit.com 99:775, \" Source: http://www.kwik-fit.com 99/98 1709 pounds = 770 Kg () 100:800, \" Source: http://www.kwik-fit.com 101:825, \" Source: http://www.kwik-fit.com 102:850, \" Source: http://www.kwik-fit.com 103:875, \" Source: http://www.kwik-fit.com 104:900, \" Source: http://www.kwik-fit.com 105:925, \" Source: http://www.kwik-fit.com 106:950, \" Source: http://www.kwik-fit.com 107:975, \" Source: http://www.kwik-fit.com 108:1000 \" Source: http://www.kwik-fit.com .in -2 .nf \" { F Maximum sustainable speed. (from reifen.com) GI km/h MPH G 90(&) H 210 My winter tyres L 120(&) M 130 N 140 P 150 Q 160 Low speed (vans etc). R 170 S 180 T 190 U 200 V 240 150(*) My summer tyres VR >210 W 270 Y 300 Z ? (*) ZR >240 (*) = Information from manufacturer "Continental" (&) = Information entry from vendor reifen-fix.de. .fi \" } .in -4 .\"------- .\" Ron caravan. .\" Ron From Web or jhs .\" made in korea .\" HANKOOK .\" RAO 8 Radial PlyRating=8 .\" 175 14 C Size=175R14 .\" 99/98 Q Index=99/98Q .\" Max load 1709 pounds ( = 770 Kg .\" 65 PSI .\" OWL Outlined white letter sidewall .\" RWL Raised white letter sidewall .\" T/T Tube Type .\" T/L Tubeless Type .\" XL Extra load .\" Web Refs .\" http://www.hankooktyre.com.au/products/product_search.asp?search=175 .\" http://www.hanta.co.kr/hantax/english/tire_product/tire/index_02.html .\"------- Do not mix different tread types on same axle. (My Subaru dealer says for Legacy 4WD, keep all 4 tyre manufacturers etc the same to avoid eg different height of tyres causing stress on the 4 wheel drive.) My snow chains for old car, quoted as: .\" Manufacturer Rud. Item Code 97 917 Other number 45 117 .\" 2 packs of 2 in plastic box @ DM 320/pair < ADAC Sendlinger Tor 12.1985 .in +4 .nf \" { 175/70-13\0\0\0165\0\0\0-13 145\0\0\0-14\0\0\0155\0\0\0-14 165/70-14\0\0\0135\0\0\0-15 145\0\0\0-15 .in -4 .fi \" } .\"------- My snow chains for new car, quoted as: .\" Purchased 12.2001 DM 134 inc mwst @ ATU, Model ARK6 05 or 15 .in +4 .nf \" { Yet to type in. .fi \" } .in -4 .\"------- .nf \" { .I Tyre examples of program Input : Output .in +4 .ti -2 Old car .br 175 70 13 : outer_diam_mm=575, o_diam+width_mm=750 .ti -2 Old chains alternate 165 70 14 : outer_diam_mm=586, o_diam+width_mm=751 .ti -2 New car winter tyres .ft B 195 60 R 15 87V : outer_diam_mm=615, o_diam+width_mm=810 .ft R New car summer tyres .ft B 205 50 R 16 87V : outer_diam_mm=615, o_diam+width_mm=810 .ft R .fi \" } .sp PS .br Aluminium Versus Steel Wheel Rims: .in +4 Obviously a lighter wheel spinning fast is easier to turn; but rubber tyre weight probably makes difference between different metal weights not so significant, especially as metal rim in middle, where less significant for rotational inertia (for calculations: square of radius), whereas rubber weight further out.. .sp Germans use steel wheels/ rims on winter tyres, aluminium (or steel) on summer tyres. I've never heard of aluminium rims used on winter tyres, aluminium would damage from snow chains. .sp As aluminium is weaker than steel (but doesn't rust (well not as such though some corrosion occurs)) aluminium rims are thicker, so reducing any weight advantage of less dense metal; Just as aluminium cycle frames aree thicker than steel bikes, so I'm not really sure hom much benefit aluminium has over steel, especially as more expensive. .sp Personally I reckon my old car, driving in summer with winter tyres, felt about twice as sloppy, & more wind drift if sudden side wind at speed. .sp Some Winter (& some Summer) tyres have a V profile, so don't mix left & right tyres: else instead of throwing slush out sideways, you'll slither on top of it ! .in -4 .SH BUGS Theory may be half baked. See all disclaimers. .SH Nomenclature English & American & German: "Car" = "Auto" = "PKW/Privat Kraft Wagen", "tyre" = "tire" = "reife", "exhaust" = "muffler" = "auspuff", "bonnet" = "hood" = "?", "boot" = "trunk" = "?", "engine" = "motor", "petrol" = "gas" = "benzin" American law requires their "tire" manufacturers to produce more information on the side of their tires, than British tyre manufacturers need to. .SH OPTIONS None .SH EXIT CODE 0 for success if 3 numerics are read, else 1. .SH COPYRIGHT Program & Document Copyright Julian H. Stacey, Munich, 1998.10.21. .br Free Use, but I disclaim all liability ! .\" .so author.jhs .SH FILES None. .\" End of file