love2fly Posted March 25, 2019 Posted March 25, 2019 I'm intrigued/staggered by the amount of flats I see whenever I watch a pro MTB race like Epic or the UCI world cup events as per what we saw in Stellenbosch etc. I know these guys are riding faster than the weekend warriors BUT they weigh comparatively nothing......I have heard stories of tread being skimmed to save weight, and little sealant being used also to save weight.Then in this year's Epic, Forster getting a flat and commentators saying he used a thin sidewall tyre. Is there anyone on the Hub that knows for sure ie can comment factually?As far as I can recall Forster even flatted in a sandy section....
Robbie Stewart Posted March 25, 2019 Posted March 25, 2019 They use tires not much thicker than a condom...to save weight.One has to wonder about the penalty in weight vs the penalty in time, which has in days past cost a team the win, for a stage, and eventually the overall.
love2fly Posted March 25, 2019 Author Posted March 25, 2019 You only have to look at Nino & Lars, cost them 9 minutes and in a more matched environment that could have been the race...They use tires not much thicker than a condom...to save weight.One has to wonder about the penalty in weight vs the penalty in time, which has in days past cost a team the win, for a stage, and eventually the overall.
DieselnDust Posted March 25, 2019 Posted March 25, 2019 I'm intrigued/staggered by the amount of flats I see whenever I watch a pro MTB race like Epic or the UCI world cup events as per what we saw in Stellenbosch etc. I know these guys are riding faster than the weekend warriors BUT they weigh comparatively nothing......I have heard stories of tread being skimmed to save weight, and little sealant being used also to save weight.Then in this year's Epic, Forster getting a flat and commentators saying he used a thin sidewall tyre. Is there anyone on the Hub that knows for sure ie can comment factually?As far as I can recall Forster even flatted in a sandy section.... Factually the commentators said Forster and Nino were running a 170tpi tyre. Less rubber in the high TPI casings but also overlaid plies so that presents a more convoluted pathway for a thorn or nail to penetrate.Most of the tyre issues stem from cuts and more rubber isn't going to stop the tyre from getting cut on sharp rocks. A stiffer thicker casing is going to be less compliant so its going to get cut more easily. You really want an infinity elastic tyre that is infinity tough.the reality is that a compromise needs to be made between those requirements
philip.maree Posted March 25, 2019 Posted March 25, 2019 I saw Andri Frischknecht comment on Instagram that they are running Pepi's Tire Noodle inserts. Think that is why they struggled to unseat the bead when Forster had that puncture where they lost 9 minutes.
V18 Posted March 25, 2019 Posted March 25, 2019 That's going to be a hard disagree from me. More burly casings (more rubber) usually results in more sidewall cut durability. More resistance to folding under low pressure. More resistance to burping and pinching.The compliance theory is just that. Theory. A cut isn't formed by something being unable to comply to a surface. It's formed by an edge (rock shard) sliding past a surface about to get lem'd. Being more compliant whilst sliding past a sharp thing will do nothing to prevent the cut. The surfaces are already sliding past each other. More rubber. More to cut.
Thermophage Posted March 25, 2019 Posted March 25, 2019 Someone should have told my GRID, Double Down and Super Gravity sidewall tyres that they puncture more easily because they're stiffer. Dammit
Captain Fastbastard Mayhem Posted March 25, 2019 Posted March 25, 2019 Generally speaking, the more layers of casings (plies), the lower the TPI rating and the more sidewall reinforcement a tyre has, the better the puncture protection / durability of the tyre. Foam inserts sometimes help with this, but I'd take stiffer sidewalls over an insert any day of the week. XCM / XCO pros generally (not always) favour weight savings over puncture protection, which results in these sorts of issues cropping up. Those Maxxis Aspen tyres they were running are like toilet paper, especially at the 170tpi end. Compliant, sure, but one sneeze and they tear. They're single ply casings (not multi-ply, that's generally only on "gravity" casings) and though they have a higher TPI count for the material casing (the amount of threads in an inch of casing material - normally cotton / silk / poly / kevlar etc) they don't have as much puncture protection as the thickness and strength of the individual casings is lower than a 60tpi tyre, for instance (lower threadcount = thicker threads = stiffer casing = more durability) You then also get additional sidewall & casing protection technologies, such as Snakeskin, Silkshield, GRID, Exo, Exo Plus, Doubledown and so on. These generally refer to either a layer of engineered fabric, sandwiched between layers of rubber from bead to bead, only under the tread or only on the sidewalls; or a Butyl (or similar material) insert which, again, is only on the sidewalls, over the whole tyre, or only under the tread. You can get only one or a mixture of those extra protective measures in your tyres, depending on what your priorities are. The number of threads that cross through one square inch of a single ply of the tire’s casing. Lower TPI gives better puncture, cut and abrasion resistance but is heavier. Higher TPI conforms better to the terrain, offering a smoother, more comfortable ride while reducing the weight of the tire.Maxxis TPI ratings are the threads-per-inch of a single casing ply, as compared to some competitor TPI ratings. Using Maxxis's site / explanations as they're pretty clear. Silkworm is an exclusive material incorporated into the casing of select models, increasing puncture and tear resistance. Silkworm is featured under the tread as a breaker. SilkShield offers protection from bead to bead whereas Silkworm is found under the tread only.SilkShield provides an additional level of protection for sidewalls as well as under the tread. An extremely cut-resistant and abrasion-resistant material added to the sidewalls of select mountain tires. This densely woven fabric is also lightweight and highly flexible, ensuring that the performance of the tire remains unaffected. Choose EXO Protection for exceptionally rocky, treacherous trails where the chance of sidewall cuts and abrasions is high. Our EXO+ construction combines two of our best puncture protection materials: SilkShield and EXO. The SilkShield layer runs from bead-to-bead with a layer of EXO along the sidewalls. Combined, these two materials create EXO+ which improves tread puncture protection by 27%; sidewall durability by 51%; and resistance to pinch flats by 28%. DoubleDown (DD) is the next step in the evolution of the dual-ply tire casing for enduro racing. Two 120 TPI casing layers reinforced with a butyl insert provide the enduro racer with the support and protection of a downhill tire, but in a lighter package.
love2fly Posted March 25, 2019 Author Posted March 25, 2019 Factually the commentators said Forster and Nino were running a 170tpi tyre. Less rubber in the high TPI casings but also overlaid plies so that presents a more convoluted pathway for a thorn or nail to penetrate.Most of the tyre issues stem from cuts and more rubber isn't going to stop the tyre from getting cut on sharp rocks. A stiffer thicker casing is going to be less compliant so its going to get cut more easily. You really want an infinity elastic tyre that is infinity tough.the reality is that a compromise needs to be made between those requirementsI also heard the 170 TPI quote but disregarded as the Aspen Nino is reportedly riding has a TPI of about 120 and the Ardent I ride around 60 so Im not sure where the 170 comes in unless its some prototype....but wouldnt a higher TPI weigh more....
love2fly Posted March 25, 2019 Author Posted March 25, 2019 That's going to be a hard disagree from me. More burly casings (more rubber) usually results in more sidewall cut durability. More resistance to folding under low pressure. More resistance to burping and pinching.The compliance theory is just that. Theory. A cut isn't formed by something being unable to comply to a surface. It's formed by an edge (rock shard) sliding past a surface about to get lem'd. Being more compliant whilst sliding past a sharp thing will do nothing to prevent the cut. The surfaces are already sliding past each other. More rubber. More to cut.I tend to agree with this seeing my Ardent and Crossmark sidewalls squeezing through rocky gaps....little deflection.
Captain Fastbastard Mayhem Posted March 25, 2019 Posted March 25, 2019 Factually the commentators said Forster and Nino were running a 170tpi tyre. Less rubber in the high TPI casings but also overlaid plies so that presents a more convoluted pathway for a thorn or nail to penetrate.Most of the tyre issues stem from cuts and more rubber isn't going to stop the tyre from getting cut on sharp rocks. A stiffer thicker casing is going to be less compliant so its going to get cut more easily. You really want an infinity elastic tyre that is infinity tough.the reality is that a compromise needs to be made between those requirements Yes, thicker casing is less compliant. That's the only correct thing in that highlighted area. Your previous argument (showing Enduro / DH pros "also puncturing") to prove your point is a foolish one. They ride faster & harder, on more demanding terrain and with more exacting demands of their tyres than the XC pro's do. If your story were true, they'd also be running Exo casings as "more rubber / stiffer casings don't improve puncture / cut protection". But no, they're all running at least DD / Super Gravity / Black Diamond / WCS Tough etc casings, and mostly DH casings. For extra puncture protection. Funny, that. As are the XCO pros on their trail bikes. Hmm. I also heard the 170 TPI quote but disregarded as the Aspen Nino is reportedly riding has a TPI of about 120 and the Ardent I ride around 60 so Im not sure where the 170 comes in unless its some prototype....but wouldnt a higher TPI weigh more....170 TPI casings are available on some of the more "racy" tyres as an option. Increases conformity to the trail, reduces durability, weight & puncture protection.
love2fly Posted March 25, 2019 Author Posted March 25, 2019 Interesting....It would be interesting to calculate how many more wstts you would need for a slightly heavier but more puncture resistant tyre.....and/or you could compute the extra time in a stage given the higher weight at same wattagen- vs a couple of minutes once or twice with a ouncture...Im also not buying that Avancini and Fumic's much spoken about hydration packs are so revolutionary and beneficial....somebody smart out there can calculate the trade off carrying 750ml extra over two stages vs a 30 second or less stop...?
DieselnDust Posted March 25, 2019 Posted March 25, 2019 That's going to be a hard disagree from me. More burly casings (more rubber) usually results in more sidewall cut durability. More resistance to folding under low pressure. More resistance to burping and pinching.The compliance theory is just that. Theory. A cut isn't formed by something being unable to comply to a surface. It's formed by an edge (rock shard) sliding past a surface about to get lem'd. Being more compliant whilst sliding past a sharp thing will do nothing to prevent the cut. The surfaces are already sliding past each other. More rubber. More to cut. Correct more to cut but it will cut. It may not cut all the way to a rupture. But then what does this tyre weigh? >800gr?
Thermophage Posted March 25, 2019 Posted March 25, 2019 Correct more to cut but it will cut. It may not cut all the way to a rupture. But then what does this tyre weigh? >800gr?There are tyres that weigh less than 800g?! Whhhhhat? I mean 1 mistake or a sneeze in the wrong direction and bye bye bye...Esp with such little travel on a bike.
Milkman Posted March 25, 2019 Posted March 25, 2019 The other reason ( the major reason I think ?? ) with the pros puncturing a bit more than your normal weekend warrior is tyre pressure .In order for them to ride around corners and in single track at the speed they do ( and they really do go faaaast ! ) the guys have to ride their tyres at low pressure for more grip . And as with the thickness of the rubber - there is also a trade-off when it comes to low tyre pressure . Your sidewalls are a lot more exposed when your tyre is soft ( as anybody who has ever ridden 4x4 offroad in sand knows ) .
Thermophage Posted March 25, 2019 Posted March 25, 2019 Interesting....It would be interesting to calculate how many more wstts you would need for a slightly heavier but more puncture resistant tyre.....and/or you could compute the extra time in a stage given the higher weight at same wattagen- vs a couple of minutes once or twice with a ouncture...Im also not buying that Avancini and Fumic's much spoken about hydration packs are so revolutionary and beneficial....somebody smart out there can calculate the trade off carrying 750ml extra over two stages vs a 30 second or less stop...?Twould be. I suspect over multi days racing you would probably save from Watts with the lighter tyre than heavier one....even with the highly increased probability of punctures. But i mean to plug and bomb a tyre takes what, 2 minutes maybe? The camelback...I dunno that is also quite a lot of extra mass too.
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