Truing wonky tyres (now more concern with why one's come off the rim!)

[Pale Rider]

I am a bit confused, are you trying to mix up 26” and 700c wheels and tyres and the same bike?

No, he had had cheapo solid tyres on 26" rims and wanted to fit 26" clinchers.

I suggested he compare the rim profile with another rim to see if the 26" rim was properly designed for clinchers.

He said he could do that with a 700c rim from another bike which he has awaiting a tyre.

 

[wafter]

Isn't there meant to be a hook on the rim for the bead to grip?

If so, that should be the same on any size of rim.

Yes; there are hooks present on both rims and they look approximately the same in this respect, but given the difference in intended tyre size I think a direct comparison is of limited value.

I've just remembered there's a knackered cheapo MTB down the road that's been pulled out of the river; the tyres are falling off that; maybe I should go and take a squiz at that as a reference!

I am a bit confused, are you trying to mix up 26” and 700c wheels and tyres and the same bike?

No, as per my previous posts the issue is with a 26" tyre on a 26" rim. I'm not that thick!


After a bit of a trawl I found this thread on the subject amongst others; interesting that Schwalbe are mentioned several times as that's the brand I'm having the issue with too. I've also found a damaged bead mentioned a few times; which would would be a feasible proposition given their condition. Thinking about it, this tyre also took quite a bit less effort to fit than the one on the front, which I also think is potentially telling. I guess it'd be worth measuring the rim (if I can) and comparing it to the front to rule out the possibility of it being undersize.

The more I think about the ride the more I think this problem started within the first few miles of use, while the front tyre appears to have remained absolutely fine; suggesting in my mind a greater chance of an issue specific to the rear tyre / wheel rather than a fundamental compatability problem between rim and tyre.. but again the rear tyre is seeing the bulk of the load so this could well be a factor too.

I'm going to have another go at re-seating the tyre today, now I'm not attempting it on the side of the road by torchlight with freezing hands, but I don't expect a favourable outcome tbh. This has really opened my eyes as I've never encountered such an issue in the past and had always assumed that by design this wasn't really possible!

Thanks for all the thoughts; I'd be interested to hear any more. Obviously I'll be speaking to the tyre supplier and hope that they'll play ball...

 

[Joffey]

It might just be me but if I'm riding along at any speed I don't fancy an old wonky tyre blowing out or unseating and causing me to crash. I know we all like a bargain but tyres are something (in my opinion) you shouldn't bodge.

Ask for a refund and buy yourself some fresh new rubber.

 

[jay clock]

Put some talcum powder or soapy water on the tyre wall and inflate them as high as you dare.

There is amazingly special stuff for this Schwalbe Easy Fit Special Assembly Liquid for Bicycle Tyre withs with Sponge Applicator - 50 ml

View: https://www.amazon.co.uk/dp/B000RW5FVA/ref=cm_sw_r_cp_api_i_MS2yEb6KB0MKG


It works well although I only had it because a friend offered it. It won't obviously help make your tyres fit the wrong rims!

 

[wafter]

It might just be me but if I'm riding along at any speed I don't fancy an old wonky tyre blowing out or unseating and causing me to crash. I know we all like a bargain but tyres are something (in my opinion) you shouldn't bodge.

Ask for a refund and buy yourself some fresh new rubber.

Thanks - in principal I totally agree and generally steer clear of cheap and nasty / budget offerings. However as you say everyone likes a bargain, money's tight and (rightly or wrongly) I'm not averse to buying quality branded items when reduced because they're old stock or shop soiled.. this tyre is a well-respected brand and came from a reputable shop so other than a bit more time spent fitting I didn't anticipate any problems..

I've been in touch with the suppliers so now can only wait and see how they handle it. Looking at it in the cold light of day it seems pretty obvious that it's a tyre defect as it now looks decidedly sloppy on the rim and I could probably remove it just with my hands; while the front one took quite a lot of persuasion with tyre levers to get it on.

There is amazingly special stuff for this Schwalbe Easy Fit Special Assembly Liquid for Bicycle Tyre withs with Sponge Applicator - 50 ml

View: https://www.amazon.co.uk/dp/B000RW5FVA/ref=cm_sw_r_cp_api_i_MS2yEb6KB0MKG


It works well although I only had it because a friend offered it. It won't obviously help make your tyres fit the wrong rims!

Ta - although it seems that getting the tyre on an off is the least of my worries!

 

[Smokin Joe]

Thanks - on paper yes they're correct - the rim is unmarked but the solid tyre that came off is marked 26" / 559mm, as are those that went on in replacement..

Another thought - what about compatable rim width? The rims are a little under 19mm wide internally (at their narrowest point, measured across the inner edges of the lip) and the tyres are 35mm. Doesn't seem excessive to me but then I'm used to usually just fitting the same size as whatever comes off..

Now that is what I would suggest is your problem.

 

[wafter]

Now that is what I would suggest is your problem.

Thanks - on that suggestion I've done a bit of googling and the following Mavic chart robbed from Bike Rumour seems to suggest (if I'm interpreting the numbers correctly) that 19mm / 19c rims should be good for anything from 28mm to 62mm(!) tyres, and that 35c rubber should be good an rims between 17mm and 22mm.

There's also a Schwalbe chart on the same page, which is a bit more conservative but lists 19mm as the middle ground of three recommended rim widths for 35mm tyres:

In other news I looked at the shafted tyre a bit more today; managing to remove it from the rim fairly easily using just my hands so something clearly wasn't right. Further investigation revealed the bead reinforcement (two 1mm diameter steel bands) to be broken at one point and hanging out of the tyre; that'll be the problem then!

The remaining question is whether the tyre was originally knackered and would have failed regardless, or whether its failure was caused by a fitment / incompatability issue with the rim.


I've replaced a tyre on one of my road bikes today so (while I know the rims are different!) I took some measurements of each just for comparison; for what it's worth.

Rim​	Width between Lips, mm​	Lip Overhang, mm​	Lip Depth, mm​
700c​	12.9​	1.9​	1.6​
26" (Suspect)​	18.9​	2.0​	2.6​

These were arrived at through wholly inappropriate use of a vernier, so please allow a bit of waggle room. Width between lips is the internal width at the OD of the rim. Lip overhang is the distance between the internal face of the lip and that of the groove beneath it (measured on one side). Lip depth is the distance between the OD of the rim and the bottom of the lip where it meets the groove.

The only thing that potentially concerns me is the deeper lip depth (which excessive might not give room beneath to allow the bead to seat in the groove), although obviously the 26" rim has its roots in MTBs so it's possible that it's built a bit heavier.

I took some measurements from the 26" tyres; with the textured section at the bead being 7mm deep (on an uninflated tyre) and when mounted on the front rim there's around 1mm of this showing above the OD of the rim; meaning there's around 6mm of bead inside the rim. Taking into account the rim depth this gives around 3.4mm depth of bead below the bottom of the lip; to engage the groove and and hold the tyre on the rim.

The tyre has two 1mm diameter steel bands in each side that apparently run next to each other across the tyre and are located just outboard of the inside edge of the tyre, so probably occupy the inner-most 2mm of the tyre's ID, and the last 2mm of the 3.4mm-ish of the bead located beneath the lip.

So the reinforcement in the bead appears to line up well with the groove in the rim, which is promising.

I also measured the effective depth of the 26" rim; i.e. the distance from the rim's OD to the bottom of the channel that houses the tyre at the bead, which came in at 6.9mm; giving 1mm clearence between the bottom of the rim channel and ID of the tyre and again supporting the idea that the rim is intended to take a tyre of the type fitted.


I think on the balance of probability (given the tyre's supplied condition, apparent compatability with the rim and the fact the front's been fine) it's likely that the tyre was supplied damaged (either with the bead reinforcement weakened / bent or broken); the tyre subsequently failing under the additional loads encountered during use.


Anyway, we'll see what the suppliers say..

 

[Yellow Saddle]

It sounds like you have a non-clincher rim. Show us a good photo of the naked rim's inside, from a few angles. Let's check this out.

 

[wafter]

It sounds like you have a non-clincher rim. Show us a good photo of the naked rim's inside, from a few angles. Let's check this out.

Given the apparatus at hand and black rims I'm struggling to capture anything meaningful; hopefully this "artist's" impression of the rim's section might be of some use - all dims in mm for the sake of completeness...

 

[Yellow Saddle]

Given the apparatus at hand and black rims I'm struggling to capture anything meaningful; hopefully this "artist's" impression of the rim's section might be of some use - all dims in mm for the sake of completeness...

View attachment 507625

Thanks for taking the trouble to do the measurements and sketch.

I have no meaningful explanations, so I won't speculate.

 

[wafter]

Thanks for taking the trouble to do the measurements and sketch.

I have no meaningful explanations, so I won't speculate.

No worries, I appreciate you asking at least. On paper at least I think it's promising; the rim has a hook and the dims appear appropriate to suit the tyre fitted, but I'm little experience in this area so anything further would be total supposition. Would be good to get some comparative dims from another 26" rim but I only have this size fitted to this one bike..

 

[Ajax Bay]

1. [I bought] some discounted old stock tyres; reduced (with full disclosure) because they're a bit old and wonky.
[fitted and rode bike]
2. one side of the rear tyre had completely unseated from the rim and the tube was visible between the two; the rubbing being the tyre on the mudguard stay
maybe 15% the entire bead being visible because it's lying outboard of the rim.
3. what do we reckon is the cause? So far I'm thinking one or maybe more:
- Defective tyre (reinforcement compromised, allowing it to stretch circumferentially)
[offers 4 other suggestions]
4. the rim tape as the size I was recommended is (IMO) a bit on the wide side - the channel in the centre of the rim is a shade under 15mm wide while the tape is 20mm; meaning that it rides up the sides of the channel;
5. the rim is unmarked [so no idea what dimensions]
6. what about compatable rim width? The rims are a little under 19mm wide internally (at their narrowest point, measured across the inner edges of the lip) and the tyres are 35mm.
7. Not had much luck with tyres in the last week; had a blowout on my road bike last weekend
8. everyone likes a bargain, [even if] old stock or shop soiled.. this tyre is a well-respected brand and came from a reputable shop
I looked at the shafted tyre a bit more today; managing to remove it from the rim fairly easily using just my hands so something clearly wasn't right. Further investigation revealed the bead reinforcement (two 1mm diameter steel bands) to be broken at one point and hanging out of the tyre; that'll be the problem then!

OP pinged the cause as the first 'option': tyre defective, allowing it to stretch circumferentially.
4 - comment. 20mm rim tape is fine for 19mm internal width rims.
6 - comment. I'd say 19mm internal width rims would be ideal for a 35mm width tyre.
7 - question. Do tell us what caused your tyre to blowout on your road bike.
8 - comment. Wasn't a bargain was it?
9 - comment. Bit more time examining your tyres and less time chatting on here (though I completely acknowledge this is CycleChat) might have allowed you to discover this quicker. Consider yourself lucky that, purely by chance (50%), you fitted the defective tyre to the rear. Otherwise, such a defect could easily have resulted in a front tyre blowout on your first ride, which likely would have not been pretty, if at speed.
And finally, I bought 2 tyres which seemed little used and of the width I wanted, and fitted them. Only a 100km later the front tyre started bulging one side. Fortunately, like the OP I wasn't far from home, nursed it back and replaced it, but left the other one on the rear (ERROR) - for my end-to-end. After 680km, at 6pm on Day4, near Garstang there was a wheel rotation frequency noise. The rear tyre's sidewall had degenerated in identical manner (Giant 2SL or summat). Bicycle shop was closed but fortunately, and on the suggestion of a kind Lancastrian, at 6:15 I found a garage up on the A6 which sold children's bikes and a selection of tyres. A Marathon Plus was soon mine: getting it one the rim was a whole other game, mind. Rode on to my overnight N of Lancaster and to the end a few days later.
My advice to the OP would be to replace their front tyre immediately.

 

[wafter]

OP pinged the cause as the first 'option': tyre defective, allowing it to stretch circumferentially.
4 - comment. 20mm rim tape is fine for 19mm internal width rims.
6 - comment. I'd say 19mm internal width rims would be ideal for a 35mm width tyre.
7 - question. Do tell us what caused your tyre to blowout on your road bike.
8 - comment. Wasn't a bargain was it?
9 - comment. Bit more time examining your tyres and less time chatting on here (though I completely acknowledge this is CycleChat) might have allowed you to discover this quicker. Consider yourself lucky that, purely by chance (50%), you fitted the defective tyre to the rear. Otherwise, such a defect could easily have resulted in a front tyre blowout on your first ride, which likely would have not been pretty, if at speed.
And finally, I bought 2 tyres which seemed little used and of the width I wanted, and fitted them. Only a 100km later the front tyre started bulging one side. Fortunately, like the OP I wasn't far from home, nursed it back and replaced it, but left the other one on the rear (ERROR) - for my end-to-end. After 680km, at 6pm on Day4, near Garstang there was a wheel rotation frequency noise. The rear tyre's sidewall had degenerated in identical manner (Giant 2SL or summat). Bicycle shop was closed but fortunately, and on the suggestion of a kind Lancastrian, at 6:15 I found a garage up on the A6 which sold children's bikes and a selection of tyres. A Marathon Plus was soon mine: getting it one the rim was a whole other game, mind. Rode on to my overnight N of Lancaster and to the end a few days later.
My advice to the OP would be to replace their front tyre immediately.

Thanks for your thoughts; in response to your points and questions raised:

4. Looking at the tape now its been held in place by the tube it looks perfectly positioned; however initially I had a bit of an issue seating it centrally in the rim's channel so had concerns about its edge protruding above the bead seat abrading the tube.

6. Indeed, it seems that a 19mm rim / 35mm tyre is ideal from the source material I can find on the net.

7. I'm unsure of the root cause but the failure mode was that the fibre reinforcement in the side wall failed, causing it to rupture under pressure from the innertube and subsequently allow the unsupported tube to expand unconstrained and burst. The bead and associated area of the tyre remained intact. The tyre had covered around 1.5-2k miles and was only part worn. I'd guess that the fibres failed because of one of the following:

- Fatigue loading due to being run under-pressure
- Fatigue loading due to being incorrectly seated
- Degradation due to water ingress
- Inherent weakness due to a manufacturing defect
- Inherent weakness due to incorrect storage or handling

To the best of my knowledge the tyre had always been run at an apporpriate pressure so I don't think that's the cause. I did have issues with the replacement tyre sitting a little high at the valve due to the thickness and width of the rim tape; I've since binned the tyre but still have the failed tube and the rupture is not at the valve so I don't think this is the cause either; although I did find similar if less extreme issues with the rim tape at other locations.

Degradation due to water ingress could be an issue as the bike it was fitted to has been used in all weathers, however I don't know what (presumably synthetic) fibre material is used in the tyres or whether it's susceptable to moisture absorption. I have found one other case on the net of the same tyre failing in the same way from around the same approximate time as I purchased my example, so it's possible it could have been one of a defective batch.. regardless it's years old now so I've got zero recourse with the suppliers.

8. I see no need for such a comment - the tyre is a well respected brand sold by a reputable shop that was sold as being serviceable if cosmetically non-ideal. Do you want an apology for the offense my need to maintain this bike on a budget has evidently caused to you?

9. Again, why the need to put the boot in again and imply that this failure was somehow my fault? The tyre was supplied as fully serviceable and was inspected to the best of my ability and knowledge with no obvious defects found. Once fitted it remained well-aligned on the rim and inflated to its working pressure with no signs of deformation, poor seating or impending failure. Other than the fact that it went on the rim somewhat easier than normal (something that I only really noticed in retrospect and of course varies between different tyres) how do you suggest I'd have detected a broken bead hidden inside the tyre carcass? I joined this forum to improve my understanding from those more knowledgeable; not to court the totally un-necessary condescention and bile of others for my daring to use the board for its intended purpose.

I've taken the issue up with the supplier and will await their response before deciding my next course of action. Thankfully the bike in question is only a town hack so unlikely to see high speeds, but I appreciate the need for caution.

 

[Ajax Bay]

It wasn't a bargain because whatever price you paid, it was not fit for purpose.
I'm not suggesting one shouldn't take advantage of a bargain ( I'm all for it, like @Joffey) but caveat emptor and a careful pre-purchase check. I'm taking no offence: just commenting/chatting. Please apologise to yourself: certainly not me.

I suggested "Bit more time examining your tyres . . . might have allowed you to discover this quicker."
"How do you suggest I'd have detected a broken bead hidden inside the tyre carcass?"
Inspect the tyre before use, or immediately after you'd spotted that it wasn't right, and see that "the bead reinforcement (two 1mm diameter steel bands) [were] broken at one point and hanging out of the tyre".

I joined this forum to improve my understanding from those more knowledgeable; not to court the totally un-necessary condescention and bile of others

My turn to apologise: sorry "Bile"?? I don't see any contributors' comments which contain 'bile'.
And how have the comments on this thread increased your understanding, exactly? It already seems very good: you have identified without any help from anyone, what was wrong with the tyre. "un-necessary condescention" ?sp?
"The remaining question is whether the tyre was originally knackered and would have failed regardless, or whether its failure was caused by a fitment / incompatability issue with the rim. "
@Yellow Saddle was reluctant to speculate but I will: The tyre was originally knackered and would have failed regardless - your activity fitting the tyre and riding out, only to discover it was 'wonky', would not cause the beads to fail (actually part).

 

[wafter]

It wasn't a bargain because whatever price you paid, it was not fit for purpose.
I'm not suggesting one shouldn't take advantage of a bargain ( I'm all for it, like @Joffey) but caveat emptor and a careful pre-purchase check. I'm taking no offence: just commenting/chatting. Please apologise to yourself: certainly not me.

I suggested "Bit more time examining your tyres . . . might have allowed you to discover this quicker."
"How do you suggest I'd have detected a broken bead hidden inside the tyre carcass?"
Inspect the tyre before use, or immediately after you'd spotted that it wasn't right, and see that "the bead reinforcement (two 1mm diameter steel bands) [were] broken at one point and hanging out of the tyre".

My turn to apologise: sorry "Bile"?? I don't see any contributors' comments which contain 'bile'.
And how have the comments on this thread increased your understanding, exactly? It already seems very good: you have identified without any help from anyone, what was wrong with the tyre. "un-necessary condescention" ?sp?
"The remaining question is whether the tyre was originally knackered and would have failed regardless, or whether its failure was caused by a fitment / incompatability issue with the rim. "
@Yellow Saddle was reluctant to speculate but I will: The tyre was originally knackered and would have failed regardless - your activity fitting the tyre and riding out, only to discover it was 'wonky', would not cause the beads to fail (actually part).

Anyway, trolling aside thanks for your input..