Author Topic: Rear tyre bulge?  (Read 5436 times)

Matt2matt2002

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Rear tyre bulge?
« on: October 11, 2015, 04:35:23 pm »
Take a look at my rear tyre.

Marathon Plus 1.75.
Little wear to them.
I put them onto my Raven a month or so ago replacing the 2 inch ones that saw me through my Pamir trip.

The white beading on one side is not in line with the rim.

What have I done? Should I refit the tyre?

Thanks for your comments.

Matt



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Danneaux

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Re: Rear tyre bulge?
« Reply #1 on: October 11, 2015, 04:40:41 pm »
Yes, Matt, a refit is certainly in order; the tire's bead has become entrapped below the bead seat.

You may be able to get away with simply deflating the tube, then grabbing the casing with your hands and rocking it to either side before lightly reinflating and then rolling the tires to release the beads. Park Tools used to market a pair of "tire pliers" to aid bead-seating, but I have not seen them in their catalog for many years. They were once a standard in the Schwinn-brand mechanic's shop service kit.

A little soapy water (Fairy Soap? and water) will help ease the bead into place, along with a short period of inflation near the top of the Thorn-recommended maximum.

When remounting the tire, be sure to also check the tube is not trapped beneath the bead.

All the best,

Dan.
« Last Edit: October 11, 2015, 04:59:12 pm by Danneaux »

Danneaux

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Re: Rear tyre bulge?
« Reply #2 on: October 11, 2015, 04:57:09 pm »
Adding a bit...

I mount my tires a little differently than others, but find it avoids such problems almost completely and has proven itself over the last 35 years or so.

Starting with a loose tire, I inflate the tube until it barely has "structure" -- just becomes round, but is still largely flaccid.

I then place it entirely in the tire, indexing the valve stem with the center of the tire label on the right side of the wheel/tire. This makes it easy to locate and repair future punctures -- and makes sure I find and remove the culprit that caused the puncture.

Next, I place the valve stem in the rim hole, followed by the bead nearest me, seating it fully next to the valve.

Then, starting at the valve, I work my way 'round till the bead nearest me is fully seated in the rim.

I then reverse the wheel so the loose-bead side faces me, and I start seating the bead at the valve, working both sides away from the valve at once. By the time I'm done, only one small section of tire bead is left unseated, and it is opposite the valve.

I then gather the tire upward, starting from the valve, which is pointed down. Progressively pinching the tire casing from the valve upward ensures both beads drop into the center of the rim, freeing space for the final bead-seating, which usually pops easily into place using only my hands. If the tire casing is hard to mount, I can usually resolve the problem by letting a bit of air out of the tube.

I've found this method works well for narrow or wide tires, folding or rigid beads, and I never have need to use tire levers. Reversing the method to demount, I rarely need tire levers at all, and only then sometimes to start the removal process. Of course, if tolerances aggregate against you, this is no longer true. A small-diameter tire on a large-diameter rim will fight you to the end. I do use Rema talc inside my tires and on my tubes, and I have found it serves as a lubricant to ease the tire bead over the rim sidewall and edge. It also helps avoid trapping the tube beneath the bead as the tire casing seats on the rim.

After the tire is mounted, I then pinch the casing all-round to ensure the tube is not trapped beneath the bead at any point, particularly at the valve. Since there is little air in the tube (remember it is aired up just enough so it is no longer flaccid), I press down on the wheel and roll it for one complete turn -- again, to relieve any tube trapped beneath the bead.

At this point, I usually insert the wheel and secure it with the quick release. This avoids any interference between a wide tire and narrow brake openings. It is not usually a problem with v-brakes, but can sometimes be a problem with older road/randonneur bikes that have narrow fork brake boss spacing if one runs relatively wide tires on relatively narrow rims (i.e. 32mm tires on Mavic MA-2 20mm rims) with cantilever brakes whose pads cannot open fully due to interference with the fork blades. I then fully inflate the tire with the wheel in the bike.

Works well for me and seems to avoid the problems I had before adopting this method -- including entrapped beads, as shown in your photo above.

All the best,

Dan.

jags

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Re: Rear tyre bulge?
« Reply #3 on: October 11, 2015, 05:03:22 pm »
Dan your gonna have to start a video channell  8)
the soapy water trick is a good one ;)

Matt2matt2002

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Re: Rear tyre bulge?
« Reply #4 on: October 11, 2015, 05:30:42 pm »
Thanks Dan
Sun well over the yard-arm here in UK - so will refit Monday morning.

I am pretty good at making sure the tube is not trapped against the rim ( having had a couple of pinch flats following refits )     - but must have over-looked quality control this time.
It is a little puzzling for me since I usually check this kind of thing.

I am half inclined to believe it happened after I had fitted the tyre.
And that would be strange indeed.

Matt
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Danneaux

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Re: Rear tyre bulge?
« Reply #5 on: October 11, 2015, 06:06:02 pm »
Quote
I am half inclined to believe it happened after I had fitted the tyre.
It can sometimes happen, Matt, if the tires is plunked down hard on the pavement (in the bike or alone) before it is fully inflated. The shock can be enough to unseat the bead and drop it into the central rim well.

Can -- and does! -- happen to us all from time to time.

Also, the occasional tire can have the reflective side stripe misapplied so it is "off", but the real tipoff in your excellent and clearly focused photos is where the molded line above the bead dives beneath the rim's sidewall. That's what I use as a check to make sure the tire is seated even and true.

All the best,

Dan.

Danneaux

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Re: Rear tyre bulge?
« Reply #6 on: October 11, 2015, 06:22:23 pm »
I was mistaken; Park's tire seating pliers are still available, but the price is dear:
http://www.cambriabike.com/Park-Tool-Tire-Seating-Pliers.asp

Best,

Dan.

mickeg

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Re: Rear tyre bulge?
« Reply #7 on: October 11, 2015, 11:18:18 pm »
Photos did not load for me, so not sure what happened.  But if you described what I think you described, you might want to make sure your rim tape is still in place.  If a tire bead could have pushed the tape to one side your tubes could get cut on a hole in the rim from the spoke nipple.

Matt2matt2002

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Re: Rear tyre bulge?
« Reply #8 on: October 12, 2015, 03:01:33 pm »
Photos did not load for me, so not sure what happened.  But if you described what I think you described, you might want to make sure your rim tape is still in place.  If a tire bead could have pushed the tape to one side your tubes could get cut on a hole in the rim from the spoke nipple.

good point. I'll remove tyre completely and start again
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Danneaux

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Re: Rear tyre bulge?
« Reply #9 on: October 12, 2015, 03:49:59 pm »
Quote
you might want to make sure your rim tape is still in place.
Good suggestion, mickeg.

Speaking of rim strips, I always keep a spare tucked in my underseat bag. I have found some of them tend to part at the join in the very high temperatures I sometimes encounter in my desert touring. It is much nicer to simply install a replacement already on hand rather than making a repair or substitute with duct tape, as the heat causes the tape adhesive to run and make a mess. Though I always bring a small tube of beta-cyanoacrylate adhesive with me on tour, it doesn't always stick well to some of the plastics used for rim strips. The replacement really comes in handy then.

All the best,

Dan.

mickeg

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Re: Rear tyre bulge?
« Reply #10 on: October 13, 2015, 06:35:49 pm »
I have always used the cotton adhesive type rim tape.  I have had the tape shift in position, but fortunately never had a flat from that yet.

I never carried a spare tape that would work for rim tape, instead I only carry a small roll of vinyl electrical tape.  Perhaps I should reconsider.  The electrical tape would not hold against much inner tube pressure.

Danneaux

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Re: Rear tyre bulge?
« Reply #11 on: October 13, 2015, 06:57:33 pm »
Hi Mickeg!

I finally had to give up on adhesive tapes because the extreme heat of summer desert touring caused the adhesive to flow, making a terrible mess in the rim and gluing itself to the tube. Worse, it seemed to eventually cause the rubber to deteriorate and split where the adhesive made contact, so it was a switch to plastic for me.

The difficulty over the years (for me) has been finding plastic tape that was structurally stiff enough to span the spoke wells on double-wall rims. The old yellow Michelin rim strips have been the best I've found for 700C wheels. In the days when I toured in gravel on 1in tires at an eye-watering 125psi (to make up for the lack in volume), the tube would eventually herniate into the rim wells and split where it was stretched thin. In those days (~35 years ago), it was hard to find quality touring tires in wider widths in my upper-left corner of the YewEssay, so I made do with what I could find -- tires intended instead as trainers for racing cyclists. It was much less than ideal, but surely improved my bike-handling skills. In gravel, with a touring load, it felt like I was riding ice skates or steel-banded wagon wheels. At the lower pressures I run in my 700C and 26in tires these days, nearly any of the current strips have worked well. I like Ritchey's woven strips, but the Schwalbe blues are not bad. SJSC's house brand that work well too. the main thing I have to watch with the non-adhesives is to make certain the strip is matched to the width of the rim well and that it stays in place when mounting the tire, so it doesn't shift. Without adhesive, there is a greater possibility it will be dislodged, but if it is sized properly, that risk is minimized, though I still check every.single.time I remount a tire.

Among the adhesive tapes, I preferred Velox Fond de Jante ("Bottom of the rim"), as it came in a couple of widths, didn't stretch much, and the adhesive was more stable than many others.

All the best,

Dan.

mickeg

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Re: Rear tyre bulge?
« Reply #12 on: October 13, 2015, 10:08:30 pm »
Dan,

I was sure you were going to say when you ride your bike as fast as you generally do, that the adhesive fails from the road friction heat.  The desert heat sounds more realistic than self generated heat from rolling friction.

I really do not have heat issues.  On my trainer, the tire has run about 20 degrees hotter than ambient air, nothing to worry about.

Braking while going down Going to the Sun Road from Logan Pass on my Sherpa with a full camping gear load, I stopped twice.  First time the rims did not feel too warm, second time I stopped the rims felt like you would expect black metal to feel in the hot sun so I squirted some water from the bottle on the rims and waited about five minutes before rolling again.  That is the only time I have had hot rim concerns.  There were a lot of steep downhills on Pacific Coast but the total elevation lost per hill was small enough that heat was never an issue for me.

Danneaux

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Re: Rear tyre bulge?
« Reply #13 on: October 14, 2015, 12:30:28 am »
Quote
I was sure you were going to say when you ride your bike as fast as you generally do, that the adhesive fails from the road friction heat.
  ;D

Oh, I wish that were the case, mickeg! If only! When I'm riding regularly, I hum along in a cruising window of about 17-21mph/27-34kph, but not much faster unless it is bombing downhill on the tandem with a willing stoker and the conditions are right. Never had rim/tube/tire/rimstrip overheating there, 'cos I use my Arai drum drag brake to aid the self-energizing cantilevers. On night runs, I've sometimes seen the drum brake glow a very dull red after long, steep downhills -- I wouldn't have wanted to touch it.

Cruising fully loaded, I seem to average a realistic 15.6mph/25kph in most good conditions, but of course that goes way, way down with poor road conditions, headwinds, etc. I recall one day on the steep gravel roads of the Bohemia Mining District of Oregon's Calapooya Mountains where I struggled to make it 16 miles all day, and again last summer churning along on the deep sand roads of Hungary's dike-tops, where I toiled all day to make a measly 48km/30 miles. In the humidity, *I* sometimes got hot enough to melt, but the tires, tubes, patches and rim strips held up fine.  ;)

Pulling things back to Matt's original question a bit...

While nothing like the issue on Matt's tire, I have had a problem with my rigid Duremes wobbling a bit even with the beads seated correctly. The reflective striped asre a little "off", but not so much as the casing itself. It doesn't seem to bother in practice, but it sure looked weird while I could still see my front tire (I don't now, thanks to the extended front mudguard). The Marathon Deluxe on AndyBG's Raven Tour last summer had no such issues.

All the best,

Dan.

Matt2matt2002

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Re: Rear tyre bulge?
« Reply #14 on: October 14, 2015, 01:57:43 pm »
It was the white reflective strip

I deflated the tyre enough for me to check things out. The strip is not equal distance from the tyre edge and so it 'dips' in at one point.
This gives the impression of a 'pinch'.

But many thanks to you all for taking the time to comment. And I have printed out Dan's tips on fitting a tyre.

Guess its good to check the tyre out for this kind of thing before fitting.

Matt

« Last Edit: October 14, 2015, 06:56:21 pm by Matt2matt2002 »
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