Pushbike HELP!

[Motu]

OK,I give up,help me out you pushy types.

I'm a pushbike commuter these days,and I'm having puncture problems,like every day.I'm not new to tyres and tubes,used to do heaps of car tyre punctures with tubes in the day,and still use motorcycles with tubed tyres....I thought I was pretty savvy with them.I have been over the tyre with a microscope (truly,one of those ones on a headband) and can see nothing to puncture a tube.I have wire brushed,sanded,rustproofed and painted the rim,and the rimtape is perfect.There is a lump where the rim (steel) is welded,but it's always been there,and I have sanded it smooth.So that's my prep.

The old tube was really nasty,when I pumped it up it distorted really bad,like one of those sausage dogs they make out of balloons at the school fair.I thought it might be twisting inside the tyre and getting stressed,so tried talcum powder....and still got a flat.So I got a new tube,a good Kenda one (yeah right) But 2 days later it's flat again.Tonight I go to repair the puncture,blow up the tube - and it turns inside out!!!!! WTF??? These tubes are going to be wanting to twist all out of shape inside the tyre,that can't be good surely? But even my new tube is distorted.

So - is this normal? Do all pushbike tubes distort into weird shapes outside the tyre?

And why do I keep having flaties? Never happened before....this is new.I don't like that welded seam,and that's all I can find to doubt in the whole rim and tyre.

[sAsLEX]

I get lots of glass punctures, well got whilst running cheap tires.

Got some better tires with a Kevlar belt in them which seem to cope except when its wet and the glass makes it way in easier. Oh it would be nice if the council occasionally earn its rates and cleaned the roads, but I realise this is asking too much.

You have enough pressure in them and not getting pinch flats?

[Ixion]

Front wheel? Too many wheel stands
Rear wheel? Too many stoppies

Dunno, sorry. Pushbike engineering is strange and weird. It's probably some side effect of that incomprehensible derailleur gearchange gizmo.

[Ixion]

Actually, I think this is a none too subtle message form the biker gods, reminding you that you're supposed to be a biker not a treadling poof, and instead of fixing flats , you should be getting that Ducati back on the road. That would be a far superior commuter

OMG. Oh I just had the most horrific obscene thought. You don't wear lycra do you ?

[madandy]

Go to a good bike shop and spend a bit more on some quality tyres and tubes. Carry a spare tube with you so repairs can be made in the comfort of home or the lunch room.
I had a bad run of punctures once and put it down to poor manufacturing standards with the cheap tubes.
Or you can find those old school 'no more flats'! With decent suspension or a well padded modern seat you hardly feel the bone shaking harshness they create.
What sorta bike you riding?

[Motu]

Got some better tires with a Kevlar belt in them which seem to cope except when its wet and the glass makes it way in easier. Oh it would be nice if the council occasionally earn its rates and cleaned the roads, but I realise this is asking too much.

You have enough pressure in them and not getting pinch flats?

I used to look after the postie bikes here in Huntly - they use a kevlar outer liner to help stop punctures.Try riding a pushbike here,there is more glass than seal,the only thing helping the grass look green is all the broken Steinies.So no,not glass,I've looked really hard....a girly look y'know....

It's the rear getting flats,and it was pretty hard when I left work,harder than the front.But I ride around the lake,it's gravel,lots of little steps like over a couple of bridges,curbs etc.....and it always goes flat around the lake.I unweight the front,but it's hard to unweight the rear over bumps - any tips for that (no clips) This is an old Avanti mountain bike....but it's just a road bike with mountain bike bars.I have smooth road type tyres too.But this puncture thing is new - I go around the lake heaps,hit all sorts of crap.

[sAsLEX]

I used to look after the postie bikes here in Huntly - they use a kevlar outer liner to help stop punctures.Try riding a pushbike here,there is more glass than seal,the only thing helping the grass look green is all the broken Steinies.So no,not glass,I've looked really hard....a girly look y'know....

It's the rear getting flats,and it was pretty hard when I left work,harder than the front.But I ride around the lake,it's gravel,lots of little steps like over a couple of bridges,curbs etc.....and it always goes flat around the lake.I unweight the front,but it's hard to unweight the rear over bumps - any tips for that (no clips) This is an old Avanti mountain bike....but it's just a road bike with mountain bike bars.I have smooth road type tyres too.But this puncture thing is new - I go around the lake heaps,hit all sorts of crap.

If its landing too hard on the rear it will normally put two little holes or "snake bites" in the tube.

Oh and you dont look for the glass run your hand around inside the tire, you soon feel if there is anything there as it doesn't take much,

[McJim]

Have you got decent rim tape?
Could be there is a gap and the tube is expanding into the spoke eyelet. Could you post a photo of lumpy tube and wheel rim please?

Cheers.

[Motu]

the rimtape is perfect.

Read the first post,it always helps.

This is the tube,it doesn't look too bad here,maybe the patch straightened it out a bit.But you can see the valve stem pointing to the outside! That means it will be trying to untwist in the tyre.I've never seen a car or motorcycle tube do this....or a pushbike tube for that matter.But I have two tubes that look like this....hence the question - is this common?

You can also see my magnifying glasses,I don't miss much with these.Also I've turned the tyre inside out,dismembered all it's atoms and reassembled them into a tyre again....nothing in the tyre.However the construction has me doubtful - the cords are right there,easy to chafe the tube.Because the tube twists,I have no idea if the punctures are against the rim,or the tyre.

I may have to just see if I can find some sort of quality tube.

[xwhatsit]

Pushbike engineering is strange and weird. It's probably some side effect of that incomprehensible derailleur gearchange gizmo.

There's a funny word -- cupping? -- used to describe how the spokes are shorter on one side, to create an asymmetrical wheel to allow room for the dérailleur gear cluster. Rim's not distorting?

[slopster]

You would know if you were pinch flatting it you really have to hit a sharp edge hard and you'd hear the metallic ring as the rim whacks into it. Higher tyre pressures will reduce your flats significantly whatever the cause if you can handle the rougher ride.

If you are doing long descents and braking for extended periods with rim brakes the rims can get hot enough to soften the glue on the patches and let air out.

Remember when changing the tube to inflate it just enough to give it its shape before putting it in the tyre. Otherwise it can get kinks in it and rub against itself. And dont ever use a tire lever to put a tyre back on. Thats all I can think of for now

[Motu]

Yeah - that's something I didn't let you in on in the original post.....the rim is the same shape as the tube.Trying to save on tyres I fitted the tyre to the inside....hence the special tube required for this modification.

[Disco Dan]

May be a stupid question - have you checked the tire for a foreign object? Rim may be fine, but you could have a bit of glass/staple etc embedded in the tire that you cannot see, but when under pressure/load reveals itself enough to puncture the inner-tube.

[YellowDog]

i had a similar problem many years ago. i was not as thorough as you have been however this was my solution:

squirt some 3-in-1 oil into the valve and then push it in and out several times.

it's the dry valve that is leaking and not the tube!

(in my case this was the cure)

good luck to you with this really annoying problem,

[BiK3RChiK]

I Carefully run my fingers around the inside of the tyre to see if there is any glass or metal stuck in the tyre. Sometimes I need to go around 3 or 4 times before I find the tiniest sliver. Also, I wonder if you are pinching the tube when you are re-inflating the tyre. Are you using tyre levers to put the tyre back on the rim? Often, they will pinch the tube.

M