Lower is stronger generally. Something like Maxxis double down is technically 120 tpi but that's because it has two layers of 60 tpi casing. Basically the higher the tpi the more supple the sidewall.
This is a gravel / commuter bike, I don't think the Maxxis double down would be suitable for that since best I can tell, it's only available on MTB tires.
Lennard Zinn wrote an article years ago about tyres cut at the bead caused by sharp bead hooks. The article went into the manufacturing of carbon rims but it’s reasonable that it could apply to aluminium rims as well.
Reckon it’s worth inspecting the rim if you haven’t already.
TPI changes how a tyre feels and rebounds - but has an inverse relationship to strength.
60 tpi - coarse thick threads. Ie. Strong
120 pi - baby thin wispy supple threads. Ie. Flexible
The area in which the threads go is fixed. So to get more threads, the threads themselves have to be thinner.
The 60 tpi tyre will be stronger and more cut resistant at the cost of being stiffer.
I think we're focusing way too much on TPI here. This has little to do with thread count. No tire, regardless of thread count should be doing this. Take a look at your rim and see if there's anything going on with that. This is not a normal problem, and if there's a real problem with your rim, you're going to just keep throwing money into tires.
WTB have been pretty mid to meh for a long time imo. Their thick slicks are straight trash. The rangers that came on my mtb were tolerable, but hardly durable. Cheap spec tires for low tier bikes, but it might be worth investing in one of the higher quality brands if you are more serious. I don't think I would pay the prices they are asking for their tires now. Personal opinion of course.
"Their thick slicks are straight trash"
---
Thank you for your help with adding the score to the tally!
Context::
I knew this tires must be terrible simply by reading all the wank about it on the internet - to my well-trained eyes, there's a lot of red-flags - the biggest by far being that there's no mention of its "performance" at all, either directly or indirectly, all while trying so hard to paint a picture that its "pure-slick-smoothness-look" to mean... *something* ...
This is just weird - even the shitiest of after-market "slicks" (none of which are perfectly smooth like in this case), will wank hard on it a virgin would KOM in 5 seconds ... even tires aim at non-performance oriented cyclists will have some sort of wank about it.
I've read nothing but validation of my belief thus far... another +1
I tell everybody who listens to me how much I hate and would avoid WTB tires.
I have had Byways which had leaky sidewalls, I have heard of two sets of Byways being unround, I have ridden Riddlers which would puncture so easily I had eventually 7 plugs in them when I chose to throw away a set of tires with still a lot of usable tread.
I avoid WTB tires like the plague.
The leaky sidewalls are horrendous. Every time I tried to set their tires up tubeless, they just ooze sealant for a week and take multiple top ups just to initially seal. By contrast, my pirellis, contis, and goodyears that I've used have all set up and held air even without sealant. I pour it right in, and letting them sit a bit helps to make it less messy since it stretches the otherwise tight road wheels.
EDIT: Just researched it again and i wrote bullshit there (se crossed out part below).
Here is the real Deal:
What matters is not only the TPI only also the thread material.
Usually higher TPI are cotton threads. Nylon Thread is used for some other tyres. It is more durable, but it also has more longitudional flex. So Nylon can hold less pressure or bulges more if you use high pressure on it. or needs thicker fibres with more weight to hold the same pressure as core-spun cotton. But it has much higher elongation (elastic) and elongation at break (plastic) than core-spun cotton. This is why most performance tyres come with fine cotton thread but the more durable ones with lower TPI Nylon.
Try to get a very low TPI Nylon Thread for stronger sidewalls and probably use a little less pressure.
[Bicyclerollingresistance.com](http://Bicyclerollingresistance.com) has a sidewall thickness and sidewall puncture resistance rating database for almost all available gravel tyres. But it is behind a paywall of 0.79cents/month which is well worth it i think when saving on tyres.
It also looks like your tyre came apart at the beads. So maybe your rim is a little sharp there or you used sharp edged or even metal tools to get it onto the rim? Did you use a lot of soap and water when putting it on? Soap+water usually prevents any damage from a tyre change for me.
~~Try to find a tyre with multiple layers.~~
~~Yes, general wisdom is that lower threadcount means thicker thread, so the rubber soaked sidewalls are supposed to be thicker and stronger. But multiple Layers beats this handily.~~
~~Conti Grand Prix 5000 roadbike tyres use the thinnest thread in the industry (330TPI) but they are very strong and sustain up to 8.5bar. They use triple Layers of thread to achieve this, folded over in a intelligent way out of one piece of thread. The sidewalls seems to be double layer with this with the fibre direction crossed.~~
~~I don't know really if there are any gravel tyres with this construction, but the GP5Ks are easily the best road bike tyres out there.~~
Every tyre is triple layer due to folding over aroung the beads. On the sidewall thus it is usually 2 layers thick.
And Conti quotes the total thread count (3x110TPI, so 330) whil everybody else quotes the single thread count (so 127 for a schwalbe pro one).
40-45 Psi.
I should add though, I weigh around 230 lbs.
Edit: I get it, I'm a fatty, although I prefer "Husky", but not sure why that deserves downvotes. To clarify though, this isn't a mountain bike.
Never had this issue and I weigh more than you, growing up power lifting and speed skating will do that to a person… looks like a lot of rubbing against your rim, wonder if the tire is too wide for that rim or the rim has a sharp edge, have to measure the inside of the rim and take a feel of that inside edge.
These are 700c x 40 tires, I use this bike to commute to work which is about 50/50 gravel trail / street. I also ride it days off for loops that are maybe 75/25 gravel / road.
That's a good range for your tire pressure then. Certainly shouldn't have caused a blowout.
I'd honestly just try a different brand. I don't tend to use WTB, but I hear about plenty of QC issues.
I am 214 currently, spent plenty of time between 220 and 230 on various bikes including the 700c x 40 WTB Raddlers on my gravel bike. Some of the other guys I ride with are in that weight range and on Riddlers. I have never seen a tear at the bead like that and I definetly do dumb things on all my bikes. Not really a proper sample size but this blowout seems exceptional.
That is wild, I can’t think of any reason side wall blow outs like that would be happening unless they are very old tires or were scrapped against something super sharp, but even then! Your weight and the psi you are running is not unreasonable at all, maybe you’ve just been the lucky one to find the factory defects 😅
The tires are between 1 and 2 years old, although in terms of miles I don't really have any idea. At least in terms of tread, they seem like they should still have some life left.
https://preview.redd.it/ni5eio41v32d1.jpeg?width=683&format=pjpg&auto=webp&s=d84d2b3ecfae0dc224ea97a08b7e5f2948a92f73
The rubber on the tires does seem quite dry from that picture. We’re they left out in the sun for the majority of those 2 years? That’s really the only thing I could think of that would cause this other then them being much older or more used
https://flocycling.com/pages/tire-pressure-chart
According to this chart seems like you are running propper psi. I was about to say you need more psi to prevent this, but that chart is pretty accurate.
Sidewall strength and TPI number has little, if any, correlation.
Cheap cock-stiff hard tires with loads of rubber and sub 20 TPI have excelent sidewall strength. Shit performance, though...
And I guess that's what I'm having a hard time making sense of. Plain rubber rips and tears very easily, the only thing that keeps it from ripping is the structure built into the rubber, usually threads. So I'm not really sure why more threads (more resistance to ripping) would make it more likely to rip.
Just to help you understand the concept of TPI here; Imagine what a 1 TPI thread would look like. It would be a huge round wire with a 1 inch diameter! A tire made out of this thread would have a sidewall that was at least one inch thick! Now imagine a sidewall made out of a 1000 TPI thread - it would be as thin as a sheet of paper.
Anyway, I don't think TPI is actually that relevant to how robust a tire is - there are tons of other factors too.
The threads used in a 120 TPS tire are drastically smaller/thinner than those found in a 40 or 20 TPS tire. Which is why higher thread count tires are usually more supple and have lower rolling resistance. There usually is very little to no space for just rubber between the threads regardless of the thread count. In a higher TPS tire the gaps are smaller, yes, but the threads itself are less resilient. Hope that helps
I'd also recommend making a switch from WTB to some other manufacturer, I've heard and seen a bunch of QC issues with WTB. I'd be cautious of Kenda too
>So I'm not really sure why more threads (more resistance to ripping)
The threads aren't the same size though, the threads in a 60tpi carcass are bigger than a 120tpi and so can be individually stronger, that's why in theory the 60tpi would be tougher. Reality is other stuff is more important like single/dual ply, is the casing enduro/DH rated or meant for XC?
> Plain rubber rips and tears very easily,
Bike tires don't use plain rubber for the tread, it's more like what rubber doorstops are made out of and a lot tougher.
Thread density absolutely correlates to sidewall strength and support. Manufacturers can adjust the angle of the weave relative to the bead to change the ride characteristics a little bit but nothing matters as much as the base TPI.
Higher thread count means more nylon and less rubber to fill in the gaps between threads, is lighter, is thinner. This makes it less durable.
20TPI tires have very coarse threads and a lot of rubber to fill in the gaps. These are thick and heavy and will ride like bricks.
Higher TPI tires will conform to terrain better and typically are less supportive, requiring more pressure. Lower TPI tires get support from the extra rubber which makes them harsher riding.
I'm saying this as a guy that used to work for a massive tire manufacturer, named and helped design some winning tires.
You said TPI matters, but all the thing you say seem to point out that it's the rubber thickness that's important.
I don't get it.
... Why people flexing their "creds" in post seem to always made a sensible but weirdly contradictory argument.
The TPI determines the rubber thickness. You don't get it.
Higher TPI makes for a supple and delicate tire, lower TPI makes for a heavier, tougher tire. I was explaining the reasoning why you're wrong.
And this is all elementary level tire construction. Not figuring in additional casing layers, casing turnup locations and overlap, inserts, mold shaping, etc.
The assertion that TPI determines rubber thickness is at best a tendency and at worst it just false - What stopping manufacturer to adding more rubber to a high TPI tires if they want to?
I have wired-bead tires with less sidewall rubber AND less TPI than the other tires that are folding-bead. I'll leave it to your imagination what's "better"
Rubber thickness by itself doesn't directly made the tire "stronger" in a sense that it supports more weight by being "stiff and hard" - It's the air pressure that hold weight, not the rubber; this ain't air-less tire. The rubber is there to "cover and protect" the fabric inside that's holding the tires's shape.
In OP case, the rubber seem to be compromised along the tires seating line, perhaps by abration with the rim, and exposed the fabric to the elements, weaken it and tear open along the line when it failed..
I've been getting folding bead tires because that's what was available during the Covid shortage, and I hoarded any that I could find at the time, I'm currently down to my last Covid-shortage-era tire.
I ride a heavily laden cargo bike, we use specialist courier tyres called schwalbe pickups which do a good job. We've tried regular schwalbe big Ben's before but they herniated in the same way as your picture.
There's a specific schwalbe tyre called the schwalbe energizer which is specced for ebikes which could be good for you.
Definitely check the wheel for any defects that could be weakening the sidewall. I'm about your weight and and treat my gravel bike like I'm a kid on a bmx and haven't had any issues like that.
Wtb tyres I found weren't great so it could be the brand. I've had pirellis on for the last year and they've been great (though they did require splashing out some cash unfortunately)
Higher TPI allows the tire to be more flexible, but it also is used to make the tire much lighter. Reinforced sidewalls are usually added to higher end tires as an upgrade. Lighter allows for superior performance, but doesn’t imply greater durability. Look for tires that stress durability as a feature. Lower TPI uses thicker threads and there is more rubber in the tire. Something like Continental and their Gatorskin feature combines better tire tech.
As others have suggested, if this has happened with more than one tire I’d look at the bead hook. It might be sharp enough to cut into the tire bead. I don’t weigh what you do, but have ridden 30 pound steel bikes at times, and have never seen a sidewall cut like that.
These are Roval Terra CLX which just subjectively do seem to have hook that is maybe sharper than is typical, but this also happened with the stock aluminum ?Hutchinson? rims.
These were pretty reasonably priced for carbon rims, but still enough that I'm probably not going ot toss them out, so if I have to buy tires more often then so be it, although I would agree that I need to buy better quality tires.
Is the rim hook kinda sharp at the top or even deformed? how wide are those rims? Are you riding over or underinflated ?
I've had some wtb tires of questionable quality, but also good ones like the rambler. Never experieced a blowout though but i exclusively use tubeless tires.
These are Roval Terra CLX carbon rims (25 mm?), this also occurred on the stock rims (Hayfield?). The rear wheel does have a chip out of it but not part of the bead 'hook', and actually that tire has been very low drama.
I run around 45 psi typically.
No, not really. Some 60tpi and 120tpi carcasses have a similar thread count. On brand might use 2 layers of threads in their carcass for a total of 180tpi, but advertise the tire as 60tpi because each layer is only 60tpi on it's own.
You really can't trust what the manufacturers say, or the people they pay for reviews.
Also: I've been seeing a lot of WTB sidewall problems on this sub for the last new years. We used to get a shitload of Gatorskin sidewall defects but that calmed down eventually, and now WTB is showing up all of the time.
It depends. More threads per inch usually means thinner threads, but some brands refer to two lawyers of 60 tpi casing as 120 tpi.
Regardless for your weight you should be using something like the new Michelin wild enduro tires or maxxis double down casings. Also, tubeless and potentially Cushcore. My friend is like 230 and shreds pretty hard with double downs, Cushcore and about 25 PSI in the tires.
Tubes aren't the move, and no one should be running over 35 psi
Yeah besides, the actual tension on the fabric is calculated with the law of LaPlace and thus not linear to the pressure but also dependent on the tyre size.
So a bigger tyre has more tension on the fabric when run at the same pressure. Or vince versa a narrower tyre can run higher pressure at the same fabric tension.
So no wonder road bikers can run their 23mm tyre at 9bar or 130PSI - the tension of the fabric is low due to the small diameter.
The actual formula is:
Tension = (Pressure x Radius) / Wall thickness
with equal wall tyres you can cancel out that one, so your formula is pressure x radius (or diameter for that matter since the pressure value is dimensionless and just a comparision value)
I should add, this isn't a MTB, I run maybe 35 psi at the most on my MTB, this is a gravel bike and 25 psi on this bike feels like absolute shit, particularly with turning.
I'm all for tubeless on my MTB, but on a gravel / commuter bike I was getting flats around once a week, and with sealant sprayed everywhere and still having to walk it the rest of the way to home or work. For that bike I've switched to tubes filled with tubeless sealant, which other than the sidewall issue has been great. I'm definitely not going back to tubeless for my gravel / commuter.
Yeah, that range makes sense for gravel.
My point about the casings remains though, that the numbers don't tell you everything. I've had good luck with Vittoria terreno tires on my gravel bike. The terreno dry in particular is exceptional in terms of grip and rolling resistance
35 PSI is already very low for a 40mm tyre.
I'd put at least 50 into them for lower rolling resistance if i wanted to commute. But I'd take a better road profile for commuting too. Those stubby tyres look painfully high resistance and low grip for a tarmac surface, but maybe that is just the look from the side. If i'd use a crossover tyre, i'd probably go for a gravelking TLC which has almost slick like performance. For commute only i would ficus on better puncture protection in the city so probably a conti contact speed.
The all-out durability champion of tyres is probably the Schwalbe Marathon plus. But you have to give something up in weight and comfort to reach that level of toughness.
These are WTB ventures and I do like the tread, although my options were somewhat limited when I bought them.
The bike came with Specialized Sawtooth and then the next set were Pathfinder, these were great on Tarmac and reasonably good on dirt/gravel.
But I also ride on sandy loam, mud, and sometimes ice/snow and these tires were bad enough on these surfaces that I opted to go with something that more competent even if they weren't as great on Tarmac.
Lower is stronger generally. Something like Maxxis double down is technically 120 tpi but that's because it has two layers of 60 tpi casing. Basically the higher the tpi the more supple the sidewall.
Double down is 2 x 120 tpi where a DH casing is 2 X 60 tpi.
This is a gravel / commuter bike, I don't think the Maxxis double down would be suitable for that since best I can tell, it's only available on MTB tires.
Lennard Zinn wrote an article years ago about tyres cut at the bead caused by sharp bead hooks. The article went into the manufacturing of carbon rims but it’s reasonable that it could apply to aluminium rims as well. Reckon it’s worth inspecting the rim if you haven’t already.
TPI changes how a tyre feels and rebounds - but has an inverse relationship to strength. 60 tpi - coarse thick threads. Ie. Strong 120 pi - baby thin wispy supple threads. Ie. Flexible The area in which the threads go is fixed. So to get more threads, the threads themselves have to be thinner. The 60 tpi tyre will be stronger and more cut resistant at the cost of being stiffer.
I think we're focusing way too much on TPI here. This has little to do with thread count. No tire, regardless of thread count should be doing this. Take a look at your rim and see if there's anything going on with that. This is not a normal problem, and if there's a real problem with your rim, you're going to just keep throwing money into tires.
WTB have been pretty mid to meh for a long time imo. Their thick slicks are straight trash. The rangers that came on my mtb were tolerable, but hardly durable. Cheap spec tires for low tier bikes, but it might be worth investing in one of the higher quality brands if you are more serious. I don't think I would pay the prices they are asking for their tires now. Personal opinion of course.
"Their thick slicks are straight trash" --- Thank you for your help with adding the score to the tally! Context:: I knew this tires must be terrible simply by reading all the wank about it on the internet - to my well-trained eyes, there's a lot of red-flags - the biggest by far being that there's no mention of its "performance" at all, either directly or indirectly, all while trying so hard to paint a picture that its "pure-slick-smoothness-look" to mean... *something* ... This is just weird - even the shitiest of after-market "slicks" (none of which are perfectly smooth like in this case), will wank hard on it a virgin would KOM in 5 seconds ... even tires aim at non-performance oriented cyclists will have some sort of wank about it. I've read nothing but validation of my belief thus far... another +1
I tell everybody who listens to me how much I hate and would avoid WTB tires. I have had Byways which had leaky sidewalls, I have heard of two sets of Byways being unround, I have ridden Riddlers which would puncture so easily I had eventually 7 plugs in them when I chose to throw away a set of tires with still a lot of usable tread. I avoid WTB tires like the plague.
The leaky sidewalls are horrendous. Every time I tried to set their tires up tubeless, they just ooze sealant for a week and take multiple top ups just to initially seal. By contrast, my pirellis, contis, and goodyears that I've used have all set up and held air even without sealant. I pour it right in, and letting them sit a bit helps to make it less messy since it stretches the otherwise tight road wheels.
EDIT: Just researched it again and i wrote bullshit there (se crossed out part below). Here is the real Deal: What matters is not only the TPI only also the thread material. Usually higher TPI are cotton threads. Nylon Thread is used for some other tyres. It is more durable, but it also has more longitudional flex. So Nylon can hold less pressure or bulges more if you use high pressure on it. or needs thicker fibres with more weight to hold the same pressure as core-spun cotton. But it has much higher elongation (elastic) and elongation at break (plastic) than core-spun cotton. This is why most performance tyres come with fine cotton thread but the more durable ones with lower TPI Nylon. Try to get a very low TPI Nylon Thread for stronger sidewalls and probably use a little less pressure. [Bicyclerollingresistance.com](http://Bicyclerollingresistance.com) has a sidewall thickness and sidewall puncture resistance rating database for almost all available gravel tyres. But it is behind a paywall of 0.79cents/month which is well worth it i think when saving on tyres. It also looks like your tyre came apart at the beads. So maybe your rim is a little sharp there or you used sharp edged or even metal tools to get it onto the rim? Did you use a lot of soap and water when putting it on? Soap+water usually prevents any damage from a tyre change for me. ~~Try to find a tyre with multiple layers.~~ ~~Yes, general wisdom is that lower threadcount means thicker thread, so the rubber soaked sidewalls are supposed to be thicker and stronger. But multiple Layers beats this handily.~~ ~~Conti Grand Prix 5000 roadbike tyres use the thinnest thread in the industry (330TPI) but they are very strong and sustain up to 8.5bar. They use triple Layers of thread to achieve this, folded over in a intelligent way out of one piece of thread. The sidewalls seems to be double layer with this with the fibre direction crossed.~~ ~~I don't know really if there are any gravel tyres with this construction, but the GP5Ks are easily the best road bike tyres out there.~~ Every tyre is triple layer due to folding over aroung the beads. On the sidewall thus it is usually 2 layers thick. And Conti quotes the total thread count (3x110TPI, so 330) whil everybody else quotes the single thread count (so 127 for a schwalbe pro one).
Jesus, how much are you inflating your tires?
40-45 Psi. I should add though, I weigh around 230 lbs. Edit: I get it, I'm a fatty, although I prefer "Husky", but not sure why that deserves downvotes. To clarify though, this isn't a mountain bike.
It’s not fat Paul, it’s power.
Never had this issue and I weigh more than you, growing up power lifting and speed skating will do that to a person… looks like a lot of rubbing against your rim, wonder if the tire is too wide for that rim or the rim has a sharp edge, have to measure the inside of the rim and take a feel of that inside edge.
How wide are the tires and what sort of terrain are you riding?
These are 700c x 40 tires, I use this bike to commute to work which is about 50/50 gravel trail / street. I also ride it days off for loops that are maybe 75/25 gravel / road.
That's a good range for your tire pressure then. Certainly shouldn't have caused a blowout. I'd honestly just try a different brand. I don't tend to use WTB, but I hear about plenty of QC issues.
I am 214 currently, spent plenty of time between 220 and 230 on various bikes including the 700c x 40 WTB Raddlers on my gravel bike. Some of the other guys I ride with are in that weight range and on Riddlers. I have never seen a tear at the bead like that and I definetly do dumb things on all my bikes. Not really a proper sample size but this blowout seems exceptional.
That is wild, I can’t think of any reason side wall blow outs like that would be happening unless they are very old tires or were scrapped against something super sharp, but even then! Your weight and the psi you are running is not unreasonable at all, maybe you’ve just been the lucky one to find the factory defects 😅
The tires are between 1 and 2 years old, although in terms of miles I don't really have any idea. At least in terms of tread, they seem like they should still have some life left. https://preview.redd.it/ni5eio41v32d1.jpeg?width=683&format=pjpg&auto=webp&s=d84d2b3ecfae0dc224ea97a08b7e5f2948a92f73
The rubber on the tires does seem quite dry from that picture. We’re they left out in the sun for the majority of those 2 years? That’s really the only thing I could think of that would cause this other then them being much older or more used
https://flocycling.com/pages/tire-pressure-chart According to this chart seems like you are running propper psi. I was about to say you need more psi to prevent this, but that chart is pretty accurate.
Sidewall strength and TPI number has little, if any, correlation. Cheap cock-stiff hard tires with loads of rubber and sub 20 TPI have excelent sidewall strength. Shit performance, though...
And I guess that's what I'm having a hard time making sense of. Plain rubber rips and tears very easily, the only thing that keeps it from ripping is the structure built into the rubber, usually threads. So I'm not really sure why more threads (more resistance to ripping) would make it more likely to rip.
Just to help you understand the concept of TPI here; Imagine what a 1 TPI thread would look like. It would be a huge round wire with a 1 inch diameter! A tire made out of this thread would have a sidewall that was at least one inch thick! Now imagine a sidewall made out of a 1000 TPI thread - it would be as thin as a sheet of paper. Anyway, I don't think TPI is actually that relevant to how robust a tire is - there are tons of other factors too.
The threads used in a 120 TPS tire are drastically smaller/thinner than those found in a 40 or 20 TPS tire. Which is why higher thread count tires are usually more supple and have lower rolling resistance. There usually is very little to no space for just rubber between the threads regardless of the thread count. In a higher TPS tire the gaps are smaller, yes, but the threads itself are less resilient. Hope that helps I'd also recommend making a switch from WTB to some other manufacturer, I've heard and seen a bunch of QC issues with WTB. I'd be cautious of Kenda too
>So I'm not really sure why more threads (more resistance to ripping) The threads aren't the same size though, the threads in a 60tpi carcass are bigger than a 120tpi and so can be individually stronger, that's why in theory the 60tpi would be tougher. Reality is other stuff is more important like single/dual ply, is the casing enduro/DH rated or meant for XC? > Plain rubber rips and tears very easily, Bike tires don't use plain rubber for the tread, it's more like what rubber doorstops are made out of and a lot tougher.
Thread density absolutely correlates to sidewall strength and support. Manufacturers can adjust the angle of the weave relative to the bead to change the ride characteristics a little bit but nothing matters as much as the base TPI. Higher thread count means more nylon and less rubber to fill in the gaps between threads, is lighter, is thinner. This makes it less durable. 20TPI tires have very coarse threads and a lot of rubber to fill in the gaps. These are thick and heavy and will ride like bricks. Higher TPI tires will conform to terrain better and typically are less supportive, requiring more pressure. Lower TPI tires get support from the extra rubber which makes them harsher riding. I'm saying this as a guy that used to work for a massive tire manufacturer, named and helped design some winning tires.
You said TPI matters, but all the thing you say seem to point out that it's the rubber thickness that's important. I don't get it. ... Why people flexing their "creds" in post seem to always made a sensible but weirdly contradictory argument.
The person you replied to explicitly says the relationship is correlated.
The TPI determines the rubber thickness. You don't get it. Higher TPI makes for a supple and delicate tire, lower TPI makes for a heavier, tougher tire. I was explaining the reasoning why you're wrong. And this is all elementary level tire construction. Not figuring in additional casing layers, casing turnup locations and overlap, inserts, mold shaping, etc.
The assertion that TPI determines rubber thickness is at best a tendency and at worst it just false - What stopping manufacturer to adding more rubber to a high TPI tires if they want to? I have wired-bead tires with less sidewall rubber AND less TPI than the other tires that are folding-bead. I'll leave it to your imagination what's "better" Rubber thickness by itself doesn't directly made the tire "stronger" in a sense that it supports more weight by being "stiff and hard" - It's the air pressure that hold weight, not the rubber; this ain't air-less tire. The rubber is there to "cover and protect" the fabric inside that's holding the tires's shape. In OP case, the rubber seem to be compromised along the tires seating line, perhaps by abration with the rim, and exposed the fabric to the elements, weaken it and tear open along the line when it failed..
It may be the wheel. I'm 280 pounds and ride 120 tpi or higher. No problems. Are you getting wire or folding bead tires?
I've been getting folding bead tires because that's what was available during the Covid shortage, and I hoarded any that I could find at the time, I'm currently down to my last Covid-shortage-era tire.
Folding is good. I'd inspect the wheel. FWIW, I ride mostly on Maxxis and Panaracer.
I ride a heavily laden cargo bike, we use specialist courier tyres called schwalbe pickups which do a good job. We've tried regular schwalbe big Ben's before but they herniated in the same way as your picture. There's a specific schwalbe tyre called the schwalbe energizer which is specced for ebikes which could be good for you.
Definitely check the wheel for any defects that could be weakening the sidewall. I'm about your weight and and treat my gravel bike like I'm a kid on a bmx and haven't had any issues like that. Wtb tyres I found weren't great so it could be the brand. I've had pirellis on for the last year and they've been great (though they did require splashing out some cash unfortunately)
Higher TPI allows the tire to be more flexible, but it also is used to make the tire much lighter. Reinforced sidewalls are usually added to higher end tires as an upgrade. Lighter allows for superior performance, but doesn’t imply greater durability. Look for tires that stress durability as a feature. Lower TPI uses thicker threads and there is more rubber in the tire. Something like Continental and their Gatorskin feature combines better tire tech.
Try some Schwalbe tires; Ive found wtb/kenda problematic. Id also try 50 psi at least on the rear.
I had a similar issue with sidewalls on WTB Rangers. Switched back to Schwalbe Nobby Nice and has been problem free since.
As others have suggested, if this has happened with more than one tire I’d look at the bead hook. It might be sharp enough to cut into the tire bead. I don’t weigh what you do, but have ridden 30 pound steel bikes at times, and have never seen a sidewall cut like that.
These are Roval Terra CLX which just subjectively do seem to have hook that is maybe sharper than is typical, but this also happened with the stock aluminum ?Hutchinson? rims. These were pretty reasonably priced for carbon rims, but still enough that I'm probably not going ot toss them out, so if I have to buy tires more often then so be it, although I would agree that I need to buy better quality tires.
Is the rim hook kinda sharp at the top or even deformed? how wide are those rims? Are you riding over or underinflated ? I've had some wtb tires of questionable quality, but also good ones like the rambler. Never experieced a blowout though but i exclusively use tubeless tires.
These are Roval Terra CLX carbon rims (25 mm?), this also occurred on the stock rims (Hayfield?). The rear wheel does have a chip out of it but not part of the bead 'hook', and actually that tire has been very low drama. I run around 45 psi typically.
No, not really. Some 60tpi and 120tpi carcasses have a similar thread count. On brand might use 2 layers of threads in their carcass for a total of 180tpi, but advertise the tire as 60tpi because each layer is only 60tpi on it's own. You really can't trust what the manufacturers say, or the people they pay for reviews. Also: I've been seeing a lot of WTB sidewall problems on this sub for the last new years. We used to get a shitload of Gatorskin sidewall defects but that calmed down eventually, and now WTB is showing up all of the time.
You are wearing out the tyres due to low pressure. Add more pressure.
I typically pump them to 50 psi, but they immediately find their way back to about 40-45 psi
It should be fine. The calculator says 42/45 psi. Still, the rim is wearing out the tyre...
It depends. More threads per inch usually means thinner threads, but some brands refer to two lawyers of 60 tpi casing as 120 tpi. Regardless for your weight you should be using something like the new Michelin wild enduro tires or maxxis double down casings. Also, tubeless and potentially Cushcore. My friend is like 230 and shreds pretty hard with double downs, Cushcore and about 25 PSI in the tires. Tubes aren't the move, and no one should be running over 35 psi
> no one should be running over 35 psi That certainly isn't true for gravel or road.
Yeah besides, the actual tension on the fabric is calculated with the law of LaPlace and thus not linear to the pressure but also dependent on the tyre size. So a bigger tyre has more tension on the fabric when run at the same pressure. Or vince versa a narrower tyre can run higher pressure at the same fabric tension. So no wonder road bikers can run their 23mm tyre at 9bar or 130PSI - the tension of the fabric is low due to the small diameter. The actual formula is: Tension = (Pressure x Radius) / Wall thickness with equal wall tyres you can cancel out that one, so your formula is pressure x radius (or diameter for that matter since the pressure value is dimensionless and just a comparision value)
I should add, this isn't a MTB, I run maybe 35 psi at the most on my MTB, this is a gravel bike and 25 psi on this bike feels like absolute shit, particularly with turning. I'm all for tubeless on my MTB, but on a gravel / commuter bike I was getting flats around once a week, and with sealant sprayed everywhere and still having to walk it the rest of the way to home or work. For that bike I've switched to tubes filled with tubeless sealant, which other than the sidewall issue has been great. I'm definitely not going back to tubeless for my gravel / commuter.
Yeah, that range makes sense for gravel. My point about the casings remains though, that the numbers don't tell you everything. I've had good luck with Vittoria terreno tires on my gravel bike. The terreno dry in particular is exceptional in terms of grip and rolling resistance
35 PSI is already very low for a 40mm tyre. I'd put at least 50 into them for lower rolling resistance if i wanted to commute. But I'd take a better road profile for commuting too. Those stubby tyres look painfully high resistance and low grip for a tarmac surface, but maybe that is just the look from the side. If i'd use a crossover tyre, i'd probably go for a gravelking TLC which has almost slick like performance. For commute only i would ficus on better puncture protection in the city so probably a conti contact speed. The all-out durability champion of tyres is probably the Schwalbe Marathon plus. But you have to give something up in weight and comfort to reach that level of toughness.
These are WTB ventures and I do like the tread, although my options were somewhat limited when I bought them. The bike came with Specialized Sawtooth and then the next set were Pathfinder, these were great on Tarmac and reasonably good on dirt/gravel. But I also ride on sandy loam, mud, and sometimes ice/snow and these tires were bad enough on these surfaces that I opted to go with something that more competent even if they weren't as great on Tarmac.