cycling
24. Juli, 18:22 Uhr
This is my first blog, and I know it's a bit long, but I'm prepared to adapt and aim to add imagery and video later.
This guide is compiled from things I’ve read and learnt from other guides over 40 odd years, personal experience of fixing 100’s of punctures - I once did 12 in a single day on a group ride with newbies - and stupid mistakes I’ve made along the way.
Included is all the tips to fix a puncture on a non-tubeless tyre, but if you have tubeless there shouldn’t really be a need for fixing punctures, so they say.
There’s generally 3 causes of puncture; and knowing which type can affect ease/repeat occurrence on the same ride, and outcome.
​
* Pierced outer casing through to inner tube by a sharp object (thorn, nail, wire, flint). This type of puncture can go down super fast or super slow, sometimes the offending object is obvious by still being in the outer casing, sometimes they are left where the puncture occurred.
* Snake bite puncture, so called because it normally has two holes close together like a snake bite. These are impact punctures where a low pressure tyre has impacted the inner tube between the rim and the road surface. They can also be caused by running exactly centrally over a stone that compresses the casing onto the inner tube again. These punctures normally go down straight & very fast.
* Movement of the inner tube within the casing or against the rim, tearing the valve or ripping the tube because of pulling it too far in one direction. This largely occurs when long time perishing of the inner tube makes the rubber sticky and it gets attached to the out casing - which in a lower inflated tyre can walk around the rim particularly during braking forces thereby tearing the inner tube - normally at the valve - these are preventable by using talc to overcome the stickiness between tyre/rim & casing. And by maintaining good pressure to keep the casing in one place in the rim (but such high pressure might not always be so desirable).
Where to start?
​
* If it’s a very very slow puncture and not fully flat and you just want to get home, give it a pump up, sometimes this is enough to cover the final mile (or 10)
* If it’s down properly and went down within 1 minute, don’t even think about wasting effort re-pumping it up, get to fixing it.
* Before removing the back wheel, put the chain of the bike onto the highest gear on the rear cassette (smallest cog) and smallest cog at the front. This helps in 3 ways; firstly it makes removal of the wheel quicker and simpler because the chain comes of the sprocket easier, secondly it keeps the tension of the chain down so enabling easier ‘slipping’ over the cog, and thirdly when it comes to re-inserting the wheel, you know exactly what sprocket to put the chain back onto to align the wheel and disk properly, this is often overlooked and makes the job a lot harder without this simple step. If you have disks nothing else required, if you have callipers remember to release the quick release on them to aid removal and re-insertion (particularly the latter as the wheel will likely be inflated and the tyre wider at this point).
* It’s fine to rest a bike back down gently onto the back end without the wheel in, ideally propped against a wall and rear gear mechanism onto grass, or on it’s side entirely - gear side mechanism up. Front forks require the older style quick release to be wound out about 3 mm further than it looks they need to be. This is because under the fork is a small profusion designed to keep the wheel in if the QR became loose by accident, these are affectionately known as “lawyers lips” as there were a number of claims against bike manufacturers for accidents involving the loss of a front wheel.
* With the wheel removed - have a quick visual check, a thorn is often still attached to a twig and visible from outside, knowing where the puncture is and the confidence of having removed the offending object gives peace of mind later.
* The next job is to get that casing off. Remove any valve caps, if a presto valve (the thin ones) release all the air you can so it’s totally flat, you can do this with a Schroeder valve with a finger nail pushed against the central pin, but a fully flat tyre is far easier to work with.
* With the right technique utilised there should be no need to use tyre levers - I’ve managed every tyre and rim combination with thumbs alone (and correct following of the correct technique). Worst case using levers to remove a tube you don’t intend to fix on location is just about OK, but even this can be a problem if you intend to patch on location. Tyre levers in use often pinch inner tubes giving two holes, instead of just the original one. I’d say definitely never using them to put a tyre back on.
* With the wheel resting on the ground, and sprocket leaning away from you with you bent over it, push the side of the casing facing you away from the rim with your thumbs, it should stay away, turn the wheel all the way round - so all of the casing is inside the edge of the rim. In this position the casing is then looser by a good margin. Spin the wheel so the sprocket is facing you and repeat on the other side. The casing wires/cables should now be in the middle of the rim (the valley of the rim) and therefore considerably looser. Starting away from the valve - pull a small segment of the casing over the outside of the rim edge, this is hard bit, but count to five and apply a seconds strong force it. This should pull a small amount of casing to the outside of the rim. Follow this around the wheel pulling more and more over the edge. This should leave one side of the casing inside the rim and one outside. This is all you need to remove to get to the tube.
* Put the valve hole to the top of the wheel, and pull the casing up sufficiently to lift the inner tube and the valve from the rim. Then pull the tube out. Before letting go of it, remember where it went inside the casing ie. If the valve hole is at 12 o’clock then make sure you remember which way the inner tube was. The reason for doing this will become very apparent soon.
* Using ideally a pump (or tickle of gas - see later), pump up the removed tube. It should go up a bit and then a hiss will determine where the puncture is. Remembering where that part of the tube was in the casing, pick the wheel up and run your fingers carefully (it could be glass) over the inside of the casing at that point (in most cases if the offending item is still there, your finger tips (very sensitive) will pick it up very quickly. When you find it, normally it’s possible to push it back out (from the inside) of the casing to the outside. You might need a pointed implement like a screwdriver (Allen key) to do this. Some won’t come out and have to be dug out carefully not to damage the casing, or I’ve used my teeth on occasion to pull a small one from the outside.
* Once offending item is removed - DO not assume it was only one, using the finger tip method (and there’s now no real need to remember the tube position - but it could be handy) run around the entire casing including the walls to make sure nothing else is protruding internally. Normally there isn’t
* Not finding a sharp thing, means it could have been left on the road (more likely in the rain) or be a snake bite type impact - a quick look at the identified hole will tell you this, normally it’s not then necessarily essential to do the finger tip routine, but always best not to assume.
* On the roadside (unless you’ve used all your spare tubes - I carry two as a minimum, as a thorn patch could go into front and rear at same time) it’s wise NOT to do a repair, because a) the glue can get contaminated, b) it just takes time and dosen’t always work perfectly. So replace the old tube with a new one.
* Before inserting the new (or previously repaired) tube give it a puff of gas or 10/20 little pumps - the goal is to get the inner tube circular both as a wheel shape and in its tube form. This massively helps the next stage and also stops it getting caught in the casing against the rim.
* With the wheel against your knees again and leaning into you, put the valve in first- threading the tyre under the loose casing, then push the semi-inflated tube into the casing all the way round, it will sit in it because it’s inflated slightly and circular. At a point nearby to the valve hole, begin to return the free side of the casing onto the inner part of the rim, do this to the left and right of the starting point as evenly as possible, you should then finish with a bit that won’t go over the rim too easily - opposite the valve. Sometimes they slip on this last bit with some pressure. But to ensure it’s going to be the easiest, look around the wheel and into the valley of the rim, the still loose and fully on side of the casing should be in the centre of the valley (remember it’s looser here because the wheel is smallest at this point). Once this is done - remove a tickle of air from the valve - it should help the final push. Go to the un-fitted inch or two and push against this with your thumbs (pushing away from you is easiest), it should snap on. Nearly there. Visually check the whole wheel and make sure that the casing is on all the way round, failure to do this results in a second puncture as the escaped tube pops.
* Begin to inflate the inner tube, keeping an eye on the casing staying on the rim. Once half inflated, go for the finish, to the pressure you want (another blog available/coming shortly). Some of the newer tighter ‘designed for tubeless’ rims and tyres require a massive over inflation to get the casing to snap onto the rim. You’ll know if it needs this, because as you ride off the bike will ride like a clowns bike going up and down each revolution. If you do have to over inflate to bed the rim in, then don’t forget to let it back down to a comfortable level. You’ll know the casing is bedded into the rim when it makes a loud popping sound. I have two rim/casing sets that will only bed properly using a gas canister (and often two cartridges - see below).
* Remember to replace valve nuts/tighten the valve and replace dust caps.
* Re-insert the wheel - using the same lowest sprocket for the chain, and the disk can also be a good guide for re-insertion. Always fasten front and rear quick releases with the levers facing backward for safety - it stops them getting caught by branches or anything else.
* Roll up the punctured tube and put it somewhere that you can clearly identify it as the ‘punctured one’. If you don’t you’ll end up fitting it back to a casing on the road only to be left incredibly disapointed with 5-10 minutes of your life you’ll never get back.
Inflation tools
​
* You could blow up a tube a little bit by mouth, but unless you can burst a water bottle this way, you’ll need an alternative.
* I used pumps of all sorts for years, and I still carry a very small emergency one in my bar bag. But for the last 15 years I’ve been using gas. These devices are purchasable on line or in bike shops (I can recommend a favourite as I’ve tried a few, some are rubbish) and they usually come with 2 C02 cartridges.
* When you first buy it, practice with it at home, it’s pointless wasting the gas out on the roadside.
* C02 cartridges are ludicrously expensive to anyone but the very rich. So to avoid paying ridiculous prices, google C02 suppliers or catering suppliers and buy the same size cartridge you require on-line. They’re used in various catering jobs (whipped cream makes mostly), and they’re around 25p a unit versus £2 for bike ones. If you use Nitrogen ones (they work just as well), you’ll find you need to re-inflate them after a week, as the smaller molecules of nitrogen bleed through most inner tubes. But it takes a week to go even slightly softer, so it’ll get you home economically.
* But an emergency pump is a godsend - and helps with the ‘where’s the hole test inflation’ and the small inflation before installing new tube back into casing etc.
Best advice?
​
* If you’ve not fixed a puncture before - then make sure you practice on a false one in your garden. Do this in the comfort of home versus in the rain, late home for a BBQ or shopping trip you’ve promised you’d be back for, or when you are late for an interview.
CyclingTips 
Radfahren in Stuttgart 
DC Rainmaker 
It started with a fight 
Pressedienst Fahrrad 
Fahrrad Magazin mit Testberichten & Ratgebern 
CapoVelo.com 
Radsport-News.com 
RennRad | Radsport Rennräder 
Pedelecs und E-Bikes 
MartinTriker 
Velomotion 
Carolyn Friesl Twitter 
Spoony's Bike Blog 
Tausendkilometer 
Zukunft Mobilität 
Home - HFS - Helmuts-Fahrrad-Seiten - hfs.bike 
Icebike 
FAHRRAD, DESIGN & KULTUR 
Warum ich Rad fahre 
VeloCityRuhr 
BicyclingMag 
Cyclingmagazine 
MTB-News.de 
Bikerumor 
Zwift Insider 
Velonews