FlyingCheetah Posted July 15, 2008 Posted July 15, 2008 I see different tires are available, some folding some not. My questions are: <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /> If you look at tire specs, you get tires with 120tpi, 60tpi and even 84tpi. What is this tpi? Is it an indication of the toughness of the tire? Is it the resistance against punctures? How can I evaluate what tires are the best yet affordable if I look at the specs?
KevinV Posted July 15, 2008 Posted July 15, 2008 tpi is threads per inch, basically a measure of the thickness of the weave of the fibres making up the tyre. The higher the thread count the tougher the tyre (and heavier).
Canaris Posted July 15, 2008 Posted July 15, 2008 scorpione is passionate about tpi.but the basics is TPI is thread per inch. THE higher the tpi the more tightly woven the cotton/ext is that makes the carcus of the tyre. This in turn should make it more resistant to small nicks and cuts (note small) It also makes it "tougher", "harder", "More subtle" ext and thereby increeases performance. That is why a 120tpi costs more than a 84 tpi.
controlc Posted July 15, 2008 Posted July 15, 2008 Taken off Michelin: TPI: Threads Per Inch (English measurement): the number of fabric threads per inch in the carcass of the tyre, also known as cord density. Higher-quality tyres have higher densities. Unit conversion: 127 TPI = 420 threads/dm2, 66 TPI = 240 threads/dm2, 33 TPI = 110 threads/dm2.
FlyingCheetah Posted July 15, 2008 Author Posted July 15, 2008 What tyres are you considering FC? Hi, I'm looking at the Conti Ultra Sport or perhaps something else, but I could not decide what to buy as I am on a very tight budget. I need new tires for my new (secondhand) WH-R550's I bought last week. I want to use them for racing, but I'm not yet in the league of Spinnekop, Zaskar etc. FlyingCheetah2008-07-15 03:06:48
KevinV Posted July 15, 2008 Posted July 15, 2008 Ok, not a Conti fan at all myself. Found that they ALWAYS puncture, but that's just me perhaps. I do know many riders who love them. I like Vredestein tyres, they have a decent range so try some out.I am heavy so I don't like tyres that can't be ridden at really high pressures, otherwise Hutchinsons are ok I think too. I'm sure that others can also give you plenty of input.
shaunh Posted July 15, 2008 Posted July 15, 2008 FC, save some more money and purchase the Schwalbe Ultremo's!!!The best racing tyres available (IMHO)!!!
Troi Sport Posted July 15, 2008 Posted July 15, 2008 Taken off Michelin: TPI: Threads Per Inch (English measurement): the number of fabric threads per inch in the carcass of the tyre' date=' also known as cord density. Higher-quality tyres have higher densities. Unit conversion: 127 TPI = 420 threads/dm2, 66 TPI = 240 threads/dm2, 33 TPI = 110 threads/dm2.[/quote'] from Schwalbe.com EPIhttp://www.schwalbe.com/ger/de_media/allgemein/trans.gifDescription:http://www.schwalbe.com/ger/de_media/allgemein/trans.gifEnds Per Inch (Threads per Inch): Unit for the density of the carcass fabric. the higher the EPI, the denser ther carcass and so the higher the quality of the tire.
ShortLegs Posted July 15, 2008 Posted July 15, 2008 Don't waste your money on Ultremos, unless you have money to burn Before making any decisions, check out this comprehensive test: http://www.conti-tyres.co.uk/conticycle/road_tyres/attack%20force/Resistance%20Fighters.pdf
Johan Bornman Posted July 15, 2008 Posted July 15, 2008 scorpione is passionate about tpi. but the basics is TPI is thread per inch. THE higher the tpi the more tightly woven the cotton/ext is that makes the carcus of the tyre. This in turn should make it more resistant to small nicks and cuts (note small) It also makes it "tougher"' date=' "harder", "More subtle" ext and thereby increeases performance. That is why a 120tpi costs more than a 84 tpi.[/quote'] Almost, but not quite. TPI, as everyone pointed out refers to threads per inch. However, more threads ironically makes for less resistance to cuts since the threads are much thinner. A thicker thread takes up more space and hence as many cannot be fitted into an particular space. But they're thicker and hence more resistant to cuts. That is, if you believe that thicker cords are harder to cut than thin cords. I'm of the opinion that at the thickness we're talking about, it is all irrelevant but that's another point. TPI is thus the inverse of thread diameter and a higher TPI makes for a thinner casing, which has less rolling resistance than a thick casing. In other words you can have strong or light-rolling, but not both, no matter what the little box the tyre came in says. You can't have your cake and eat it. Further throwing a spanner in the sprocket, the thinner the casing, the less presure the tyre can take. Therefore, larger tyre sizes generally have lower TPI (thicker cords) to cope with the increased stress a larger tyre at X pressure experiences has over a smaller tire with the same pressure of X. I have no idea what your term "subtle" means. It isn't in my physics dictionary. Hardness, well that's derived from the rubber used, not from the casing and has thus nothing to do with TPI. Johan Bornman2008-07-15 03:30:03
KevinV Posted July 15, 2008 Posted July 15, 2008 Hmmmm...you learn something new every day! Can't say I have ever paid too much attention to tpi, but looking at max. pressure of a tyre is similar then. Thanks JB.
Canaris Posted July 15, 2008 Posted July 15, 2008 THank you Johan for overturning all avaliable conventional wisdom. It just shows how niaive the bunch of us are.
FlyingCheetah Posted July 15, 2008 Author Posted July 15, 2008 Thanks for all your inputs. I'm 70KGs and would like to have good tires for racing without the punctures. I know that some tires are more prone to punctures than others. Puncture resistance might be a higher priority than lighter tires. What are your experience on the tires you use and your approximate weight?
Johan Bornman Posted July 15, 2008 Posted July 15, 2008 Thanks for all your inputs. I'm 70KGs and would like to have good tires for racing without the punctures. I know that some tires are more prone to punctures than others. Puncture resistance might be a higher priority than lighter tires. What are your experience on the tires you use and your approximate weight? When you're talking about high-quality racing tyres, puncture resistance doesn't come into the equation. They're all thin, have similar numbers of cords and are therefore equally puncture un-resistant. If we could measure puncture resistance, the differences wilsl be in the order of microns. Not worth hunting for. Punctures are a matter of luck or, the lack thereof. I've seen companies like Continental talk about the mythical puncture resistant qualities of their tyres by giving them hard-core names such as T-Rex Skin or tortoise shell (what's that Texan dessert rat thing with the armour plating?). It's all nonsense. Even if you made the cords of thin steel strands, they'll still get punctures. If you don't believe me, take a flattened piece of your mother's steel wool, put it on your thigh (whilst you're sitting) and stab at it with an awl. Report the results here.
turtlek Posted July 15, 2008 Posted July 15, 2008 Vitorria rubino or rubino pro's they can go up to 10 bars and i havent had a puncture and been using them all year lon (touch wood)
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