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Discuss your experiences road riding, share knowledge or other general road cycling topics. A doping discussion free forum.

Moderators: Irondan, Eshnar, Red Rick, Valv.Piti, Pricey_sky, Tonton, King Boonen

24 Jul 2017 20:53

In my experience, the danger of tubular spares rolling off the rim is largely overblown. I rode sew-ups exclusively until my favourite manufacturers (Clément and Vittoria) moved production to Asia. And I never felt the need to ride home on tenterhooks after mounting a spare.

First of all, don't forget that for many, many years, tubulars were all there was.

Image

Why are these men wearing spare tyres (plural) like bandoliers? Because in the early years of the TdF, Tour director Henri Desgrange did not allow riders to receive any external assistance. Couldn't even toss them a sammie.

There was one famous incident when a rider broke his fork, pushed the bike to the next town with a blacksmith shoppe, borrowed the smithy's hearth and anvil to mend his fork, and rejoined the race (but the mend shortly also broke). Because the rules then required that no one apart the rider make any repairs to the bike.

Few of the roads were tarmac and they not uncommonly would have several punctures in a single stage, so winning the race literally often depended on continuing to ride on the rivet despite riding on a hastily-mounted spare.

As an unsupported enthusiast rider, there are mechanical measures you could take to reduce the risk, namely glue and air pressure. Some tyre glues by their nature offer better security after a roadside tyre change. The ones that dry soft and remain tacky are better in this regard that the ones that dry hard. The ones that dry hard also usually dry faster and have a higher ultimate bond strength, so are preferred by likes of track racers and criterium riders (because of the cut-and-thrust nature of their events). But they're a PITA to dismount and the glue has little to no leftover bonding strength.

And there's also tyre pressure. The more pressure you add to a tubular, the fatter and shorter it gets, meaning it literally contracts circumferentially on the rim, rather like a Chinese finger trap.

Image

Some of the old knowledge has been watered down or lost and IMHO where modern riders tend to go wrong is thinking they can inflate the spare to the same pressure they were running in the punctured tyre and have the same security. When the truth is if you were running six bar before the puncture, you should inflate the spare to seven or eight, or maybe nine or ten if you intend pressing your luck (another reason I carry a CO2 inflator ;) ).

Spares also should be pre-glued (not everyone follows this practice, but then not everyone has roll-offs either), and a higher tyre pressure serves better to compress the glue on the tyre against the residual glue on the rim, resulting in a less marginal temporary bond.

I only ever used glues that remained tacky, and I always over-inflated any spare I mounted. And I only bothered moderating my speed after changing a puncture if the lean angle was so severe that I otherwise would have had to stop pedalling, because the lean angle was direct evidence of a high side-load on the tyre. AFAIK I never even came close to a roll-off.

Which isn't to say roll-offs don't happen, despite best, even professional, efforts.

https://www.youtube.com/watch?v=Gr89ku-K2WU

The most famous roll-off incident I can recall, Joseba Beloki, Stage 9, 2003 TdF. Not riding on a spare, naturally, but came down to a combination of unusual conditions. But there were upwards of 200 riders on the course that day and Beloki was the only one rolled a tyre.


[offtopic]
Merckx index, you might be interested to know that none other than Graeme Obree carried rollerblades when he competed in the 2013 international human-powered vehicle competition at Battle Mountain, Nevada. Well, not the whole set actually, just the wheels:

Image

To me this looks uncannily like his preying mantis position carried to its logical extreme. This was on a shake-down run, he used a fully-enclosed plastic fairing in the race.

To make his vehicle as compact (and streamlined) as possible, The Flying Scotsman sought to reduce the leg articulation which ordinarily is needed to drive pedals in a circle. So he used a straight-push pedal system that converted linear motion into circular my means of bell cranks attached to crank arms on chainwheels. He used urethane wheels scavenged from a pair of rollerblades captured inside a parallel tracks (boxed in green) as the guides for his linear-push pedals.

The stark staring maddest bit of all, madder even than the 290-inch (!!!) large gear resulting from having the first chainwheel drive a second, was the breathing apparatus. Fresh air intake came through about a 5cm hole at the bow of the fairing (effectively ram air, once at speed), connected to the engine's air intake (Obree's mouth) by means of a flexible hose scuba snorkel. Nope, not kidding.
[/offtopic]
User avatar StyrbjornSterki
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Re:

25 Jul 2017 03:30

StyrbjornSterki wrote:

Spares also should be pre-glued (not everyone follows this practice, but then not everyone has roll-offs either), and a higher tyre pressure serves better to compress the glue on the tyre against the residual glue on the rim, resulting in a less marginal temporary bond.


It's been a long time since I've used tubulars, but this statement jogs my memory. I now remember that my spares had glue on them, they were tacky to the touch. Plus, as you say, there was some glue on the rim. In any case, I do remember I never had a tire come off. I also remember opening up the old one to patch the leak, then sewing it back. Not a lot of fun.
Merckx index
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28 Jul 2017 20:30

You shouldn't be riding someplace that's too far to walk home without knowing how to fix a flat, you should not be dependant upon others for your problems that are easily remedied on your own, grow up! Sorry to be rough with you but that is the essence of the problem, maturity, unless you have some sort of physical malformity that prevents you from fixing stuff.

There are plenty of You Tube videos showing how to fix flats, watch several of them and then practice, practice, practice till you can do a flat on the rear (rear because that's the most complicated, once you can do the rear the front is a snap, and besides most flats occur on the rear so you better know how to deal with that), you should be able to do a rear flat in under 20 minutes, as you get better that time will shorten.

So you will need certain tools. A pump is crucial, but getting a crappy pump is useless and frustrating so spend some money and get a good pump like the Lezyne Road Drive large (they come in 3 sizes, get only the large one) if you have presta valves which are skinny valves, but if you have Schrader valves (large diameter just like your car valves) then you need a different pump like the Lezyne Pressure Drive; OR if you don't really care about the pumps weight, size, and looks, the Topeak Road Morph G pump can do either Presta or Schrader and is a lot easier to pump air into tires then the Lezyne; the Topeak is not a true mini, it's more of a half of a full size frame pump. DO NOT believe all the marketing hype about this or that pump can reach 160 psi, most mini pumps on the market cannot even exceed 75 psi not alone 100 to 120 road bike riding levels. The ones I listed can and do, I've gotten my Lezyne Road Drive up to 125 psi just to see how far it could get but even that one as good as it I doubt seriously it can get to 160 like they claim it can, I don't even think the Topeak Road Morph G can get that high either but I've never tried, I may do that later just for to see, but I know it can go higher than the Lezyne; fortunately no one needs to go that high, usually between 80 to 115 is all most people need based on weight and tire width. There are only maybe 2 or 3, maybe 4 at the most mini pumps on the market that reach riding PSI levels.

Watch You Tube videos on how to fix a flat.

Next you need a set of unbreakable tire irons since beginners tend to be rough on tire irons, but also these will last a lifetime, so get the Soma Steel Core levers. You need only two. Use a small rubber band to bundle the irons together so they don't rattle as you ride.

Watch You Tube videos on how to fix a flat.

Next you need a spare tube, which will be kept in your seat bag, if you don't have a seat bag get one, Topeak makes a really nice one called the Aero Wedge Pack, they come in 3 sizes, for just commuting you should be fine with the middle size. Keep your tube in its box to prevent it from getting punctured while in the seat bag. When you have a flat simply roll up the old tube tightly and forcing the air out of the valve which you may have to open as you roll and stuff it back into the box.

Watch You Tube videos on how to fix a flat.

You need a patch kit, I like glueless patches but since you're new to all of this you should start with glue on type because glue can mask errors you might make in the tube preparation process. I like Rema patches the best, they should come with a glue tube, and a piece of sanding cardboard. Carry this with you in the seat bag, just in case you flat your spare you can at least patch a tube and continue riding.

Next you watch You Tube videos on how to fix a flat.

Any other tools are not necessary at this time, only after you get more experience at biking will other tools become necessary.

Then watch You Tube videos on how to fix a flat on the road (ahh tricked you didn't I?) If I could I would come over and show you how to fix a flat but since that's impossible due to geographical locations You Tube is the next best thing, and if you watch enough of them you'll get the idea on how it's done, then simply practice practice practice at home till you can do it in under 20 minutes. If you have a tube with a hole in it, inflate the tube outside the tire till it's about 4 times it's flatted size, and listen for the air leaking as you move around the tube starting at the stem and working back to the stem. If you find the hole, or if you have a tube with no hole, well put one in it! I know, weird, but it will help you to learn how to patch, and then make sure after you followed the directions by watching You Tube videos on how to fix a flat, that once installed in the tire and the tire is pumped up to riding psi make sure that the patch holds.

Word about pumps, you might be living someplace in Europe, there are some pumps that are sold there that are not sold in America where I'm located, it may well be that there may be more pumps there that can reach higher levels of PSI then what we have here that I'm unaware of, but I know a lot pumps we have here are sold in the EU and most of those cannot reach higher levels.

If you have some sort of physical issue with fixing stuff then consider purchasing a flat resistant tire and or installing a flat liner which goes between the tube and tire. The plastic flat liners don't work as well as the cloth ones like the Panaracer Flat Away but the plastic ones are cheaper and reuseable. Tires like the Conti Gatorskin have decent flat protection, but any tire can get a flat, so be prepared.
froze
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