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Posted

Mods - feel free to move....couldn't find a dedicated bicycle sub forum.....

I have a Trek 7300 hybrid bicycle......The tires are a b*tch to put air into.....You have to remove the cap - unscrew the valve stem extending it outward - put an adapter sleeve on the threads that goes around the extended valve stem - then attach the pump (I use a portable air compressor that I have for off roading) - THEN put air in the tire - fortunately the compressor has a gauge so you can fill then reverse the procedures losing a little air (so you overfill to compensate).....

The tires take 80-100 psi so using a bicycle pump would not be as easy as the compressor......small capacity exaggerates losing air...

The front tire is OK - the rear sometimes (like today) takes 4 tries to get all parts working as they should even though the process is the same each try.....

Then I air up the wife's bike - like most bikes = attach compressor and fill - under two minutes...if that.....

The question is - has anyone put tubes with regular valve stems on their Treks to make it easier to maintain/fill.....the exisiting valve stem diameter is thinner......

I asked at the local Trek store - they said no......but that could mean they've never addressed it - or - think outside the "box".....

Posted

There is indeed a cycling forum if you look a little harder. In my limited experience the kind of valve you use is determined by the rims you are running. If you are not willing to change your rims to accommodate the larger valve stems you are out of luck.

(http://www.thaivisa.com/forum/forum/156-cycling-in-thailand/)

Would it be possible to drill out the holes in the old rims to use the new valve stems?

Just a thought.

Posted

There is indeed a cycling forum if you look a little harder. In my limited experience the kind of valve you use is determined by the rims you are running. If you are not willing to change your rims to accommodate the larger valve stems you are out of luck.

(http://www.thaivisa.com/forum/forum/156-cycling-in-thailand/)

Would it be possible to drill out the holes in the old rims to use the new valve stems?

Just a thought.

That is what I asked and they said no.....looks like aluminum - or titanium? That's my line of thinking also....just don't know downside risk......The wheels and tires are Bontrager & the wheels also say Camino on them....whether wheel, rim, tube are specialty matched I don't know....I'm a good sized guy and wanted a nice, good quality, strong, versatile bike and brought it from the states with me.....I'm not really "into" bikes or a bike guy.....

Posted

When I bought my bike they put tubes with the narrow racing valves on it. The first one failed, and I went back; they said "Sorry, we don't have a tube the same, but we'll just ream out the hole to fit the larger valve stem (car-type)... Hang about, it's got the bigger hole already" and sure enough, the second tube failed within a few weeks because the hole was too big for the skinny valve stem. The rubber around the valve stem was chafing on the hole through the rim and failed fairly quickly.

So anyway, according to the blokes at KSH there should be no problem reaming out the hole, but on the other hand you'll have a problem fitting the smaller valve stem tubes in the future. Mind, they also put the wrong tubes in, in the first place, so maybe I should be a bit sceptical.

Does anyone know if you can get a grommet to go in the hole to accept a thinner valve stem in the hole for the larger valves?

SC

Posted

When I bought my bike they put tubes with the narrow racing valves on it. The first one failed, and I went back; they said "Sorry, we don't have a tube the same, but we'll just ream out the hole to fit the larger valve stem (car-type)... Hang about, it's got the bigger hole already" and sure enough, the second tube failed within a few weeks because the hole was too big for the skinny valve stem. The rubber around the valve stem was chafing on the hole through the rim and failed fairly quickly.

So anyway, according to the blokes at KSH there should be no problem reaming out the hole, but on the other hand you'll have a problem fitting the smaller valve stem tubes in the future. Mind, they also put the wrong tubes in, in the first place, so maybe I should be a bit sceptical.

Does anyone know if you can get a grommet to go in the hole to accept a thinner valve stem in the hole for the larger valves?

SC

How about a tire patch with the right sized hole in the middle as a cushion....buffer....? Put over the valve stem + making sure the hole in the rim has no sharp edging.....

Posted

 

When I bought my bike they put tubes with the narrow racing valves on it. The first one failed, and I went back; they said "Sorry, we don't have a tube the same, but we'll just ream out the hole to fit the larger valve stem (car-type)... Hang about, it's got the bigger hole already" and sure enough, the second tube failed within a few weeks because the hole was too big for the skinny valve stem. The rubber around the valve stem was chafing on the hole through the rim and failed fairly quickly.

So anyway, according to the blokes at KSH there should be no problem reaming out the hole, but on the other hand you'll have a problem fitting the smaller valve stem tubes in the future. Mind, they also put the wrong tubes in, in the first place, so maybe I should be a bit sceptical.

Does anyone know if you can get a grommet to go in the hole to accept a thinner valve stem in the hole for the larger valves?

SC

How about a tire patch with the right sized hole in the middle as a cushion....buffer....? Put over the valve stem + making sure the hole in the rim has no sharp edging.....
 

I'm wishing now I'd not thrown out the old inner tube that was not worth repairing...

It wouldn't even need to the right-size hole in the rubber, as it would stretch to fit.

It might be better to use two layers of rubber; I should get that sorted out fairly soon, as my spare tube has a thin valve

SC

Posted

I'm guessing the rims [from Trek website] are 700c 32 hole alloys. The stock rubber appears to be 35mm wide.

There's no way you need to be ramming upwards of 100psi into them. Generally the lighter you are and wider the tyre you can lower the pressure. The happy recreational medium is a balance between ride comfort, control and anti pinch flatting. For example, I weigh 82kg and use 80-90psi on my 23mm wide road tyres, and 25-28psi on my 2.35in mtb tyres.

The skinny valve you're using [presta] is fine and easier to find in that tube size. I'd check the inside of rim for burrs around the hole, and providing your rim tape is in good nick, run a lap of electrical tape over the top. Start a few inches before the valve and finish the overlap after it. Use the valve to pierce the hole. That should give adequate protection. Don't over inflate !! smile.png

You can get a compressor inflator head for presta valves online to save time with adapters.

Posted

Wouldn't the easiest solution be to buy a high quality floor pump? My wife can easily put 110 psi in her tires with any of our pumps. Lezyne makes good ones. Topeak makes a small frame pump (Road Morph) that I've used to get 120+psi easily.

I would avoid drilling out the valve hole so your rim can accept Schrader tubes. The nut that screws on the Presta valve holds the tube in place. If you drill out the rim, there is the possibility that there will be a rough edge. A Schraeder valve can move against that rough edge and cause a failure.

If you think you have a rough edge on your rim now with your Presta valve, just cut a one square inch piece from an old tube. Put a small hole in the center and push the Presta valve on your new tube through the hole. Then insert the tube as you normally would. The small extra piece of tube should protect the new tube from a rough edge on the rim. Use your new pump to inflate to the appropriate pressure.

  • Like 2
Posted

I had the same problem on a race bike it was because I was a bit hasty and bent the valve, get a decent pump I have a ¨joe blow max¨ pumps my flyer e-bike up to six bar in a jiffy.

Posted

Sounds like you need a decent pump that fits to Presta valves without an adapter. I think your compressor/adapter combination is pushing the little spring-loaded Presta needle down too far, effectively closing off the valve. Once you get the connection right, you will be surprised and pleased at how easy it is.

  • Like 2
Posted

I suppose i should buy a pressure gauge as well...

Good pumps come with a pressure gauge built in. They're not cheap but they solve the problem.

  • 3 weeks later...
Posted

This was an extraordinary post!

There are two types of cycle valves:

1. Presta

2. Schraeder

If you look at the thousands of cyclists (amateur/pro) who ride road bikes everyday then you'll see that they all have Presta valves.

These allow higher pressures in the tyres which is what you need on skinny wheels.

The other type of valve is found on MTBs, many hybrids and utility cycles. You cannot inflate above 65psi (circa) with this type.

Both are easy to inflate without any problems whatsoever.

And you can also buy a converter for the Presta type that change it into a schraeder-type and allows you to use a pump/car inflator (and so on).

But it really is so simple: rather than a four step process described by the op, all you have to do is:

Unscrew the end of the Presta a couple of times, fit the pump, inflate and then screw up again. What could be easier? Why all the fuss? Beats me .......

  • Like 1

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