Repeated punctures in Schwalbe 700x28

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QUIST
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Repeated punctures in Schwalbe 700x28

Postby QUIST » 9 May 2019, 10:36am

I have had repeated punctures (6) in the above rear tyre- basically every time I fit a fresh (incl. 2 new inner tubes) tube after having ridden about 200 yds.

The puncture holes are not on the outside of the tube but the same side as the the valve.

To put it mildly I'm getting to be a bit fed up

I've checked the rim tape , seems ok, the tyre has no obvious thorn, glass etc ( and any way see the position of hole)

The wheel has recently been trued by a LBS - no ptobs there

Anybody got any ideas- I've tried replacing the tube- no joy- when ridden the bike doesn't ride true- there is a pronounced bump once per rotation - this makes me feel it it is something to do with the tyre- but when examined it seems fine- no indications of a split,

Thanks in advance
Last edited by Graham on 9 May 2019, 1:08pm, edited 1 time in total.
Reason: Title - capitals

reohn2
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby reohn2 » 9 May 2019, 10:42am

I think you'll find the cause of the punctures are either spoke heads or edge of spokeholes or eyelets poking through the rim tape.Or the edge of the rim tape cutting the tube.That is of course if you have rim tape fitted.
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QUIST
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby QUIST » 9 May 2019, 10:49am

Soft cloth rim tape is snugly fitted,I'll check as regardss spoke heads but thanks for your reply

Brucey
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby Brucey » 9 May 2019, 10:52am

if there is a bump once every wheel revolution but the tyre is OK then this usually means that the tyre isn't seated properly. Given that you have punctures of the sort you describe too, I think it is odds-on favourite that you have trapped part of the tube ( eg commonly it is the valve base) between the tyre and the rim.


FWIW rim tapes can look OK and still cause punctures much as R2 describes.

cheers
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QUIST
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby QUIST » 9 May 2019, 11:02am

yUP I'm AWARE POORLY SEATED TYRE- have seated it v.carefully and the same problems occurs -I was hopeful as tyre stayed inflated for 24 hrs but when ridden behaved as previously. I thought it might be a leaking valve- replaces tube, stayed inflated fine then when ridden went down

Thanks anyway

thirdcrank
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby thirdcrank » 9 May 2019, 11:05am

If you are getting a bump you can feel when riding, then presumably you can feel - or probably see - a bulge with the wheel out. Going by the location of the punctures you have described, it must be at or near the valve. If there's a bulge from the moment when you have completed the inflation but the apparently inevitable puncture only happens after a short ride, then it must be that the valve is somehow interfering with the seating of the tyre. I've been excoriated for posting this before but this is why I start at the valve when fitting a tyre: it ensures that the tyre is properly seated there before going on to what many find to be the hard bit.

QUIST
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby QUIST » 9 May 2019, 11:13am

No theres no obvious bulge after inflation, it looks fine, regular, when I stop to see if I can see the bump no joy.

I've not taken the latest punctured tube out yet but none of the others have been particularly near the valve I really am stumped - my guess for what its worth is that there is some sort of split which when the bike is ridden means it picks up something that punctures but theres no bang no sudden deflation...

mercalia
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby mercalia » 9 May 2019, 11:21am

I take it you have run your fingers along on the inside of the tyre to see if any thing sharp there? any loose rust from inside the wheel? is it double walled and debris inside it?

Brucey
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby Brucey » 9 May 2019, 11:26am

what exact kind of rim and rim tape are you using? A photo would help, with/without the rim tape fitted.

When the LBS trued the wheel did they increase the tension in the wheel much? If so the spoke ends may be poking out further than normal, or the rim tape might be moving around now where it was stuck down before.

Also (esp if they are ridden whilst soft), some recent Schwalbe tyres have the ( wholly unacceptable) feature that the bead wires can come poking out of the tyre and give you repeated punctures.

cheers
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QUIST
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby QUIST » 9 May 2019, 11:35am

I'll check about the rim tape, the spoke ends, but when I started to ride it the tyres were hard, not soft. I don't have the facility for a photo, but what you said about Schwalbe tyres and wire does rather scare me. I sure aas hell won't be buying as many more on the other hand I'm too hard up to buy another tyre currently

iandriver
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby iandriver » 9 May 2019, 12:27pm

This may involve another puncture, but make sure you align the valve of the inner tube with a known point on the tyre, such as the S in Schwalbe. It's good practice to always do this, as it helps you pinpoint the exact part of the rim/ tyre that is causing the problem. If the hole is 90 degrees away from the valve, then be looking at the tyre or rim 90 degrees from the valve hole and the S on the tyre.
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kylecycler
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Re: rEPEASTED PUNCTURES in Schwalbe 700x28

Postby kylecycler » 9 May 2019, 1:35pm

As Brucey said, if the wheel was recently trued by your LBS, one of the spoke heads might be protruding just above the nipple after being tightened - even if it's only slightly, that might be enough - you'd have to take the rim tape off to see - I'm not sure if the rim tape would necessarily protect against that. If so, the end of the spoke needs to be filed down till it's flush with the nipple. Best way is take the wheel back to the LBS and get them to sort it.

It's also possible that the rim tape is moving when you're fitting the tyre, exposing at least one of the valve holes. That in itself could be enough to cause the punctures. As insurance against that, you could wrap two layers of insulation tape around the rim before refitting the rim tape, then just poke a hole through it with a screwdriver for the valve - insulation tape might not be enough on its own but it's like a second line of defence. I find it works, anyway. That's partly because the rim tape that came with my bikes - like fibreglass packing tape - is rubbish - you need to make sure that yours is good quality, and wide enough (others can advise what's the best).

One time this happened to me, the bike was new and there turned out to be jagged 'burrs' around at least one of the spoke holes which hadn't been finished after the holes were drilled. All I needed to do was smooth them off with a small file and refit the rim tape (I also think the rim tape (same rubbish as above) was moving when I fitted the tube/tyre, exposing the spoke hole).

I suppose it's possible that the wheel was trued laterally - side to side - but not radially - for roundness - which might explain the 'bump' you mention, but I doubt that a rim would be that out of round.

Quite possibly, though, the tube might be being trapped between the tyre bead and the rim. For some reason that happened with me a lot when I was just learning how to refit a tyre, although there was more of a delayed reaction and the tyre went down through the night with a loud bang! For one thing I wasn't inflating the tube enough before fitting - you need to put just enough air in it for it to be 'round'; if that then makes it too tight to get the last part of the bead over the rim you can always let a little air out, but having enough air in the tube tends to prevent it getting trapped between the bead and the rim. Don't have too much air in it either, though, as that could disturb the rim tape.

Even though you say the punctures aren't around the valve, the tube could be trapped anywhere else, so go right around the tyre, both sides, pushing the bead in slightly till you can see the rim tape, making sure the tube isn't trapped anywhere.

Lastly, after fitting but before fully inflating, check the mould line on the tyre around the rim. Best way is to put just a little pressure in the tyre then adjust the bead with your thumbs till the mould line is equidistant from the rim. Then pump the tyre up to the maximum pressure stated on the sidewall - in other words, over-inflate - to properly seat the bead, then reduce pressure back down to what it should be. Sometimes you hear a 'pop' as you get near maximum pressure - that's the bead 'sorting itself out' on the rim. That ensures that the tyre is properly 'round' after fitting, otherwise you could get that 'bump' per revolution you mention.

One trick for tyres that are stubborn that way (usually if the tyre is relatively wide for the rim width) is to spray clear Windolene or similar around the bead before fitting - it lubricates the bead just enough to help it to settle, then it evaporates, so you won't then get the bead slipping around the rim, which might happen if you used an actual lubricant.

Sorry that's so long-winded - it's only likely to be just one of the above. Circumstantially I'm guessing it's what you'll find when you take off the rim tape, or the rim tape is moving out of position, but you'll just have to see. Either that or the tyre bead has been damaged when refitting, or faulty as Brucey suggested, so you'll have to check for that. If the holes are in the inner centre of the tube, though, it shouldn't be the tyre that's causing it.

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Vantage
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Re: Repeated punctures in Schwalbe 700x28

Postby Vantage » 9 May 2019, 1:54pm

QUIST wrote:when ridden the bike doesn't ride true- there is a pronounced bump once per rotation - this makes me feel it it is something to do with the tyre-


I had similar on a Schwalbe Landcruiser. Tyre seated properly, no cuts etc. I boiled it down to the tyre just being crap. As though the moulding process went a bit wonky.
Bill


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QUIST
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Re: Repeated punctures in Schwalbe 700x28

Postby QUIST » 9 May 2019, 1:59pm

I'll follow up what you suggested. I don't think the wheel will be out of true-I've known the LBS for yrs , hes rebuilt several bikes and built 6? others and I'm certain he would have mentioned it (hes also a wheelbuilder).

I do check the tube/tyre but will do it again in the manner suggested otherwise its going to be a q. of getting a new tyre

Anyway,thanks for your reply we'll see what happens when I next fit a new inner tube

roubaixtuesday
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Re: Repeated punctures in Schwalbe 700x28

Postby roubaixtuesday » 9 May 2019, 2:12pm

I always remove the tube with the tyre still seated on one side, but leaving the valve still in the rim, then pump up to find the hole. That gives a precise fix on where the hole is relative to both tyre and rim.