WARNING: Potential Problem with Master Rim (and possibly RS rim)

[Tawpie]

15 hours ago, Paul A said:

update the fire count thread.

This one, because of the quick action of the owner, didn't progress into a full blown battery fire—but would it have if it had been unattended?

[Rawnei]

9 minutes ago, Cerbera said:

I am wondering if higher pressures are a factor a bit tonight. We have just 1 report of a tyre coming off at 20 odd PSI right ? Are we sure he isn't mis-remembering that ?

All the other pressures mentioned seemed much higher. Also, is there any correlation in rider weight I wonder, in combination with high pressure ?

The reason I am thinking along these lines is from my own experience when I first got up to 'speed' on the stock Master. Initially my stock CST was at 35 PSI, and went into uncontrollable wobble territory pretty much as soon as I hit 25 kph or more. This unnerved me greatly, as I have never had ANY wobbles at all on any previous wheels I have owned, so I did a lot of reading, and after accepting that the stock CST 186 is a motorcycle tyre, pressures shouldn't need to be up in the 40 / 50s. I dropped mine to 30, then 25, then 23, then 20 (which was a little low) then back up to 23 where it remains. It still feels ultra stiff on the rim and up the tyre walls, there is no pressing it in like you could on the older bike tyres. 

And I am wondering about inner tubes as well. Am I right in thinking we are all using 2.75 x 18 inner tubes on a 20-22 inch wheel - am I right in thinking that if these tubes are meant for 18 inches, are they not much thinner walled when forced to inflate to the size of the Masters 20 inches+ ? Could that have some bearing on this situation ?

Franco tried different PSI settings between 20-38, he's a very seasoned rider with contacts in the industry, he wouldn't make that up, other riders was reporting 30ish PSI, Roger H had the same problem also very seasoned rider with high technical expertise, so high PSI is not the common factor here.

Re: tube all these "18-20" inch wheels are all the same size, the whole 20" thing is just a marketing ploy, they all use the same tires and tubes sizes.

The problem here is with the rim itself but I'm not qualified enough to say what exactly.

[Tawpie]

23 hours ago, Rawnei said:

Imagine how I feel about my master

I feel really bad for you... that's an absolute nightmare.

[alcatraz]

I like riding low pressures too and I was wondering if it's possible to ride such a low pressure that the tire moves around on the rim?

It's amazing the inner tube didn't pop. Must have been like 15 psi no? Those kind of pressures are MTB territory. They had to switch to tubeless to run those pressures. Tubeless has higher tolerances but you still hear of tires popping off. It's when the tolerances are on the extreme opposites. Oversized tire bead and undersized rim (but within spec).

Us riding tubed tires have much poorer tolerances. I'd advise doing that trick I mentioned. If a tire goes on "too easy" then don't use it. Certainly not at high speed and low pressure. 

Edited January 17, 2023 by alcatraz

[Rawnei]

31 minutes ago, alcatraz said:

I like riding low pressures too and I was wondering if it's possible to ride such a low pressure that the tire moves around on the rim?

It's amazing the inner tube didn't pop. Must have been like 15 psi no? Those kind of pressures are MTB territory. They had to switch to tubeless to run those pressures. Tubeless has higher tolerances but you still hear of tires popping off. It's when the tolerances are on the extreme opposites. Oversized tire bead and undersized rim (but within spec).

Us riding tubed tires have much poorer tolerances. I'd advise doing that trick I mentioned. If a tire goes on "too easy" then don't use it. Certainly not at high speed and low pressure. 

Who are you even writing to ?

Mine was 45 PSI it's in the first post.

[EUC Custom Power-Pads]

I don't know if the manufacturers print the maximum air pressure on the tires for fun. 🤔😅

CST-C186 has 32 psi maximum air pressure.

The EUC rims are also not very wide, like the motorcycle rims, which makes it even more risky.

I ride the CST-C186 at 22psi and have zero problems.

What I noticed during assembly is that the tire is pressed suspiciously far out when I inflated the air pressure to 40psi +, hoping that it centers itself. Unfortunately, the opposite was the case. 

I've long wondered about the insanely high air pressures that many people ride, fearing for the rims.  

If in addition imprecise air testers / air pumps come into play, there may even be 50psi in the tire instead of 45psi. This all together with a fat ass rider is maybe little to much. 😬

[Cerbera]

1 hour ago, EUC Custom Power-Pads said:

I don't know if the manufacturers print the maximum air pressure on the tires for fun. 🤔😅

CST-C186 has 32 psi maximum air pressure.

The EUC rims are also not very wide, like the motorcycle rims, which makes it even more risky.

I ride the CST-C186 at 22psi and have zero problems.

What I noticed during assembly is that the tire is pressed suspiciously far out when I inflated the air pressure to 40psi +, hoping that it centers itself. Unfortunately, the opposite was the case. 

I've long wondered about the insanely high air pressures that many people ride, fearing for the rims.  

If in addition imprecise air testers / air pumps come into play, there may even be 50psi in the tire instead of 45psi. This all together with a fat ass rider is maybe little to much. 😬

Interesting. That would be concurrent with my own instincts and observations, but not with those of Franco, if indeed he did have those 3 different types including the 186 coming off at 20 psi. My own instinct is that something is getting misreported there. The more I think about this problem the less I fear it happening to me at 23 PSI, and with my sparrow-like lightness, though I am of course grateful for the heads-up regardless... as mentioned before even at these low PSIs, my tyre walls are ridiculously stiff, meaning I have zero worries about my rims deforming.

Edited January 17, 2023 by Cerbera

[Rawnei]

1 hour ago, EUC Custom Power-Pads said:

I don't know if the manufacturers print the maximum air pressure on the tires for fun. 🤔😅

CST-C186 has 32 psi maximum air pressure.

The EUC rims are also not very wide, like the motorcycle rims, which makes it even more risky.

I ride the CST-C186 at 22psi and have zero problems.

What I noticed during assembly is that the tire is pressed suspiciously far out when I inflated the air pressure to 40psi +, hoping that it centers itself. Unfortunately, the opposite was the case. 

I've long wondered about the insanely high air pressures that many people ride, fearing for the rims.  

If in addition imprecise air testers / air pumps come into play, there may even be 50psi in the tire instead of 45psi. This all together with a fat ass rider is maybe little to much. 😬

Well again people had tire fall of at 20-38 PSI so high PSI is not the common factor here but possible that it could contribute in some scenarios for sure.

I rode stock CST-186 at 35 PSI prior to swapping it and it worked fine (although that tire sucks), on my S22 I have the Julier at 45 PSI (and I've swapped it once since swapping motor) just fine.

Plan now is to try the Julier again on the Master starting with 25 PSI and monitoring it closely for any oscillations or odd behaviour.

Reason for me personally to use high pressure is only for very technical things that risk damage to rim, liking bonking up steep obstacles, technical trails with lots of rocks or things like that (going up stairs is another thing that comes to mind but nothing I really practiced yet), as you know we like to push the ourselves and our wheels here and learn new things. 🙂 For normal riding I am not worried about rim damage at 30PSI + suspension.

Edited January 17, 2023 by Rawnei

[alcatraz]

14 hours ago, Rawnei said:

Who are you even writing to ?

Mine was 45 PSI it's in the first post.

To the OP (you). 45psi without popping the inner tube? That's some inner tube. Maybe that's a clue. 

Like, you might have had a leak and rode that thing down to 10psi. Then it got wedged.

Did it feel weird just before it happened?

Edited January 18, 2023 by alcatraz

[techyiam]

5 minutes ago, alcatraz said:

To the OP (you). 45psi without popping the inner tube? That's some inner tube. Maybe that's a clue. 

Like, you might have had a leak and rode that thing down to 10psi. 

No way the tire pressure is down to 10 psi. The size of the inner tube sticking out, unconstrained is way too big. It is probably over stretched too. 

[alcatraz]

2 minutes ago, techyiam said:

No way the tire pressure is down to 10 psi. The size of the inner tube sticking out, unconstrained is way too big. It is probably over stretched too. 

Yeah, but try inflating an inner tube over 10-15psi and see if it can hold. Hmm...

[Rawnei]

6 hours ago, alcatraz said:

To the OP (you). 45psi without popping the inner tube? That's some inner tube. Maybe that's a clue. 

Like, you might have had a leak and rode that thing down to 10psi. Then it got wedged.

Did it feel weird just before it happened?

You are focusing so much on my case and forgetting we have 6 testimonials with different tires and pressures and likely more people who hasn't read and stepped forward specially if this was a problem on the RS as well as some people wrote.

[Cerbera]

58 minutes ago, Rawnei said:

You are focusing so much on my case

You have to expect that I guess; we are lucky enough to have you here and talking about it - everyone else has dropped a 1 or 2 line comment and left it at that ! 

[Rawnei]

1 minute ago, Cerbera said:

You have to expect that I guess; we are lucky enough to have you here and talking about it - everyone else has dropped a 1 or 2 line comment and left it at that ! 

If my case was the only one then yeah sure but with several occurrences all with different variables then we have to zoom out to look at the bigger picture, it's not reasonable to believe that 6 people (with one user reporting 3 instances of this happening) all had a leaky tube for example.

[Cerbera]

1 hour ago, Rawnei said:

(with one user reporting 3 instances of this happening)

We simply don't have enough information here so far. Was Franco using the same inner tube on all his tests, and was that tube repeatedly inflated to the upper ranges he said he tested ? That doesn't bode well for its continuing health with his later tests for example ! If he inflated his CST to high 40s or 50s initially could that not have started microfractures in the tube that then persisted and worsened, and / or affected ALL his future tests with other tyres ?! It's just a guess, but we won't know without his additional input...

We also need to hear from anyone that has ONLY ridden at a low PSI and still had this problem, and I don't think we have one of those yet do we ? I don't count, having only done a single ride at 35 PSI before dropping it way lower, and never having had the problem, except for the wobbles on that very first ride, which is what gave me reason to think higher pressures might be part of the equation / problem in the first place....

Edited January 18, 2023 by Cerbera

[Rawnei]

10 minutes ago, Cerbera said:

We simply don't have enough information here so far. Was Franco using the same inner tube on all his tests, and was that tube repeatedly inflated to the upper ranges he said he tested ? That doesn't bode well for its continuing health with his later tests for example ! If he inflated his CST to high 40s or 50s initially could that not have started microfractures in the tube that then persisted and worsened, and / or affected ALL his future tests with other tyres ?! It's just a guess, but we won't know without his additional input...

We also need to hear from anyone that has ONLY ridden at a low PSI and still had this problem, and I don't think we have one of those yet do we ? 

Most of the people who had this problem had it some time ago and moved on from that, either selling their wheel or something else (Like Franco sold his Master as he wasn't happy with it), most people don't documents all these variables they look for a fix and move on.

A tube will not fracture from 40-50 PSI.

My tire was firm until it jumped off, the only telltale sign was oscillations (which seems pretty common for newly installed EUC tires, massaging tires is a common thing, even on brand new wheels from factory).

As I already wrote I will be using the exact same tire with a new tube at 25 PSI initially and see how it works.

Honestly I don't think we will find the exact answer here why this happens unless someone who's an expert on rims would suddenly step in and point out the problem as it was obvious to them.

Edited January 18, 2023 by Rawnei

[Cerbera]

1 hour ago, Rawnei said:

A tube will not fracture from 40-50 PSI.

It might not explode, but that doesn't mean it hasn't become stretched thin beyond specs, or structurally weakened in places - the sort of fractures I am talking about are porous ones at the micro level, that could lead to very very slooooow leaks, which perhaps don't initally manifest until weight is placed on them for a sustained period - that might explain why a tyre that feels firm when it goes on might hold up fine for a little while and then subtly deflate, or unevenly bulge during riding, which is bound to exacerbate any microfractures, and could this not lead it to fall off the rim over time, after you've stood on it for a kilometer - to me that doesn't seem like an unreasonable premise...

You're right - we may never know, but hopefully this thread will persist and the answer will become clearer with time !

Edited January 18, 2023 by Cerbera

[Rawnei]

Maybe you guys forgot but original Sherman had this problem and it was rampant, many users reporting tires falling off until LeaperKim changed the rim, made it Wider and possibly changed something else which fixed the problem.

[Cerbera]

1 hour ago, Paul A said:

Here is one result.  It may or may not be true.

or relevant, being as it is, about car tyres, alas...

This is a very specific problem within a very niche hobby. Very specific searches, such as 'Begode Master tyre fell off' don't return anything helpful except this thread !

[Paul A]

14 minutes ago, Cerbera said:

specific problem

 

The commonality might be:

'they told me aluminum rims do that a lot'

'it happens especially in the cold when the air contracts in the tyre'

[Stevebee]

On bicycles there are rims for tubed tyres that always  have a bit of a hook and rims for tubeless, some have a bit of a hook and some don’t. Tyres designed for tubes do have a hooked bead. With tubeless tyres some have a bit of a hook others do not. Was wondering if it’s a bad combination of rim shape together with the tyre profile that creates a perfect storm, which shows up more the higher the pressure. Interested to find out as I bought a Pirelli Angel that I planned to put on my V11

Edited January 18, 2023 by Stevebee

[Raptor]

Is it possible that a very skilled EUC rider, but however, uses silicone lubricant or some kind of chemical to install the tire, which can damage the tire composition. Such strange and inappropriate aids have been used in cars at one time and then similar problems arose. For some "strange" reason, I haven't had a single tire come off!? Experience with Sherman and K262 and the same K262 and MSP/RS each and MSP Michelin City Pro 80 90 14 and Pirelli Angel (wider) 90 80 14 and Heidenau K66 90 90 14. Pressures have been 29psi - 43psi and everything is ok. I always use the special "tire soap" for changing tires, and set the tire absolutely directly on the rim! Whether this is a key solution, I don't know.

[Stevebee]

The OP has already said he didn’t use any form of lubricant 

[Rawnei]

17 minutes ago, Stevebee said:

On bicycles there are rims for tubed tyres that always  have a bit of a hook and rims for tubeless, some have a bit of a hook and some don’t. Tyres designed for tubes do have a hooked bead. With tubeless tyres some have a bit of a hook others do not. Was wondering if it’s a bad combination of rim shape together with the tyre profile that creates a perfect storm, which shows up more the higher the pressure. Interested to find out as I bought a Pirelli Angel that I planned to put on my V11

We compared Master Rim and S22 rim the shape was very similar just different in size and width and none of them has a lip, on the Master there is known cases of stock tire falling of and also known case of another rider same tire that fell of for me works for them, so it's difficult to make any conclusions from rim+tire combination out of that as it seems to be happening for some riders and not for many others even with same rim+tire combination.

I have heard several times now that Master V2 rim was made wider from the V1 but I'm starting to wonder if I have this wide rim or not with Begode mixing and matching so many different parts, would be interesting to compare my rim to someone else, my rim is 38mm wide between the walls.

6 minutes ago, Raptor said:

Is it possible that a very skilled EUC rider, but however, uses silicone lubricant or some kind of chemical to install the tire, which can damage the tire composition. Such strange and inappropriate aids have been used in cars at one time and then similar problems arose. For some "strange" reason, I haven't had a single tire come off!? Experience with Sherman and K262 and the same K262 and MSP/RS each and MSP Michelin City Pro 80 90 14 and Pirelli Angel (wider) 90 80 14 and Heidenau K66 90 90 14. Pressures have been 29psi - 43psi and everything is ok. I always use the special "tire soap" for changing tires, and set the tire absolutely directly on the rim! Whether this is a key solution, I don't know.

I didn't use any chemical at all not even soap, both Franco and Roger H are very experienced riders with high level of technical knowledge I am sure they wouldn't mess up a tire swap either.

Also some of the testimonials are with tire from factory.

Edited January 18, 2023 by Rawnei

[Raptor]

44 minutes ago, Rawnei said:

We compared Master Rim and S22 rim the shape was very similar just different in size and width and none of them has a lip, on the Master there is known cases of stock tire falling of and also known case of another rider same tire that fell of for me works for them, so it's difficult to make any conclusions from rim+tire combination out of that as it seems to be happening for some riders and not for many others even with same rim+tire combination.

I have heard several times now that Master V2 rim was made wider from the V1 but I'm starting to wonder if I have this wide rim or not with Begode mixing and matching so many different parts, would be interesting to compare my rim to someone else, my rim is 38mm wide between the walls.

I didn't use any chemical at all not even soap, both Franco and Roger H are very experienced riders with high level of technical knowledge I am sure they wouldn't mess up a tire swap either.

Also some of the testimonials are with tire from factory.

However, if tire soap is not used at all, the tire may still flex when inflated! I have also come across such cases. I've also seen tire installation videos where the installer drags the tire onto the rim with a lot of force and multiple levers. With the right tools, a tire can be mounted on a 14" rim without tire levers! Could damage to the bead of the tire occur during the installation of the tires, which has caused this situation?
Sorry, Google Translate