Cycling
Introduction
Todella mukava, nopea ja ketterä ajopeli poluille, hiekkateille ja kestopäällysteelle. Mikseipä pyörä sopisi myös arkipyöräksi. Tällä pyörällä taittuu hiekkateillä ilottelun lisäksi myös työmatkat kestopäällysteellä. Pyörä on runkokooltaan XL ja on aika pitkä, joten ajajallakin saa pituutta olla ~180cm (+- suuntaan tai toiseen riippuen ajajan välityksistä). 189cm kuskille toiminut ja kuvissa 189cm kuskin säädöissä. Pyörä myydään pääasiassa ajanpuutteen vuoksi.
Pyörä on alunperin Kona Explosif maastopyörä vuodelta 2004, joka myöhemmin muutettu kippurasarviseksi monstercrossiksi.
Polkupyörän runko on materiaaliltaan alumiinia ja väritykseltään metallin värinen, alkuperäinen keula vaihdettu edellisen omistajan toimesta mustaan teräksiseen. Pyörässä on levyjarrut, mutta rungosta löytyy takaa paikka myös cantilever jarrulle. Tällä hetkellä pyörässä on alla 26" kiekot, mutta tarvittaessa tilaa riittää myös 27,5" road plus kiekoille. Runkoon mahtuu todistetusti 26" kiekoille ainakin 2.35 kumit, eikä rengastilan kanssa oltu vielä äärirajoilla.
Pyörään asennettu 2021 keväällä 10-vaihteinen MicroShift Advent X Road -osasarja (kahvat, takavaihtaja + rataspakka). Pyörässä on kiinni 36 hampainen narrow wide -eturatas. Advent X -takapakka on hampaistukseltaan 11-48, joka mahdollistaa hyvinkin kevyet ryömintävaihteet hankalaan maastoon, mutta tarjoaa samalla riittävästi nopeutta yli 25km/h keskinopeuteen kestopäällysteellä.
Satulana pyörässä on monesta uudemmasta Konasta tuttu Kona Road. Kammet ovat FSA Alpha Drive ja jarrusatulat shimanolaatua (br-m545).
Keväällä 2021 uutta osaa laitettu:
- FSA Vero Compact Road Bar (420mm) droppitanko + tankonauhat
- tektro 160mm jarrulevyt
- shimano hg-x ketju
- flättipolkimet
- Advent X road -osasarja + vaihdevaijerit
- 26" kiekkosetti
- Panaracer Gravelking SK 26" 2.1
- 36t NW eturatas
- etuhaarukka (talvella 2021)
- keskiölaakeri (talvella 2021)
Kevään päivityksen jälkeen pyörällä on ajettu vain ~350km, joten kaikki on hyvässä kunnossa eikä hetkeen pitäisi olla tarvetta päivittää.
~20km ajetut 26" 2.35 schwalbe fat frank renkaat + XLC TA-15 satulan.
Inner tube gets punctured next to the valve
Pumping:
- The problem was that my bike pump attaches rather strongly to the valve, and when removing it the rubber was being over-stretched, which resulted in the holes.
- When you pump up the tyres, just put a little air in at first and then rotate them if you need to, so the valve lines up well before pumping.
- tried to pull the valve down with the tire partially inflated. It pulled back-the start of the hernia was pushing it back up! I deflated the tire further, pushed the valve up (to get the tube from under the bead), then pulled it down and it settled easily way further out than it had been. Pumped it up,no space for a hernia, no hernia, no blow out.
Valve seat problem:
- Used to happen to me a lot with old skin wall tyres when I switched to disk brakes. https://singletrackworld.com/forum/topic/my-inner-tubes-keep-splitting-near-the-valve/ Some suggest a bit of talc on the tube so the tyre can roll without taking the tube with it. I ended up with a few drops of superglue on the tyre bead which cured it completely.
- Possible causes:
- Burrs or sharp edges on valve or spoke holes, rim tape not covering spoke holes.
- Old tyres with wire beads where strands are exposed.
- Running too low tyre pressure.
- When you change a tube, are you seating the valve tight in the rim before fitting the tyre to the rim? You need to get the tyre bead in place on the rim, go round a squeeze the tyre together, look down into the rim to see if you have trapped the tube anywhere. Check the valve stem is free to move, add a little air to lock the tyre beads in place, again check tyre is seated properly all the way round rim on both sides. Fully inflate, then screw down valve lock ring.
- only time I’ve had problems with inner tubes splitting at the valve was due to a horrid plastic rim tape
- Don't overtighten the valve lock nut, pulling the valve base hard in to the rim. It's only there for convenience to stop tube disapearing up the hole when pumping up the tire.
- A piece of 120-220 grit sandpaper (Al or C rim) should be sufficient to round off the edges of the valve hole. (https://www.bikeforums.net/bicycle-mechanics/1166876-how-keep-tire-tube-valve-seat-failing.html)
- A piece of rim tape over the hole (or completely replace the old rim tape): cut an "X" across the tape covering the hole and push the four sectors down into the hole, so that the tape covers the edges.
- Ensure that your valve stem is in straight and not at an angle when the tire is inflated. If not completely perpendicular to the rim, deflate and shuffle the tire around the rim until the valve is straight.
- Ensure that you're not torquing on the valve stem when inflating - not an issue with a floor pump, but can be a problem if using a frame pump.
- Overtightening the jam nut can pull the tube up through the valve hole causing it to fail.
- Cut a small piece of inner tube, punch a small hole in it and slip it over the presta valve before insertion into valve hole.
https://bicycles.stackexchange.com/questions/9319/how-to-prevent-holes-around-the-inner-tube-valve
Valve (inner tube) types
- Presta valve. D = 6 mm
- Schrader valve is slightly larger, D = 8 mm
- Dunlop valve. D = 8 mm
- Michelin. No lock nut at all
If a Presta valve is fitted into the Schrader rim hole, grommets or reducers are sometimes used to take up the extra space. The foremost concern with using a Presta valve in a rim for a Shrader valve isn't 'movement' of the valve stem but rather a 'hernia' of the tube through the excess space at high pressure, leading to a blowout.
- The tension nut that comes with Presta tubes does that job pretty well: basically use the Presta nut on the inner side to avoid the tube getting "pinched" in the extra space
- the Mavic adapters: the lip is supposed to go on the outside.
Rim Tape
- there are no rough edges on the rim around the valve hole
