Rawnei Posted January 13, 2023 Share Posted January 13, 2023 (edited) WARNING: Potential Problem with Master Rim! I first thought this was related to me swapping tire to the S22 tire (Jiluer J-820 2.75-14) but speaking with several other riders this seems a common occurrence with many different tires! Update: Chatting to more riders about this it seems like a more common occurrence. So far 7 testimonies including me, some testimonies include same rider testing different tires i.e. experiencing the problem multiple times, problem happened at broad range of PSI settings (20-50 PSI). Tires reported: CST-186 (stock), Jiluer J-820 (S22 Stock tire) Shinko 244, Michelin Pilot Street, Pirelli Angel, IRC Street Tire model unknown, Mitas Terra Force-MX SM 70/70-14. WARNING: Don't install the S22 tire (Jiluer J-820 2.75-14) on the Master rim as it will come off while riding, possible that this applies to other tires that are a bit wider as well as the Master rim is a narrow rim. So I really love the S22 stock tire, for me it's like an upgraded version of the Kenda 262 which I am used to so I figured I would install one on my Master as well seeing as it would be a big upgrade from the CST-186 that comes with the Master. Installing the tire was like usual, not easier or more difficult than normal, I normally run this tire at 45PSI so I did the same on my Master, after installation same thing that usually happens there was some oscillations so I massaged the tire after a first short test ride (which besides the oscillations felt good!) and it improved a lot but not fully gone. On the second test ride I rode longer and suddenly noticed that it started oscillating more, I was trying to analyze in my head if it was imagination or was becoming worse, at this point I was riding rather slowly (around 25kmh) and was searching for a bench to stop at (I know one was coming up soon) to inspect the tire but before I got to the bench the tire popped off and the wheel teleported me to the ground, fastest fall I ever had, glad I had a helmet. I had to puncture the tube here so that I could re-seat the tire so I at least could roll the wheel to nearest road and call an uber to get home. Luckily the wheel fell so fast that it cut off and controller wasn't damaged. Edited January 22, 2023 by Rawnei 1 2 Quote Link to comment Share on other sites More sharing options...
EMA Posted January 13, 2023 Share Posted January 13, 2023 weird, do you have a v2 master with the wider rim ? ( i know the s22 is a bit wider ) Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 3 minutes ago, EMA said: weird, do you have a v2 master with the wider rim ? ( i know the s22 is a bit wider ) Master V2 yes, it's a 40mm rim. Quote Link to comment Share on other sites More sharing options...
EMA Posted January 13, 2023 Share Posted January 13, 2023 so this tire is really huge, thanks for the tips, glad you are ok Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 5 minutes ago, EMA said: so this tire is really huge, thanks for the tips, glad you are ok Side by side with CST186 it doesn't look huge, just a bit wider. 🫤 Quote Link to comment Share on other sites More sharing options...
techyiam Posted January 13, 2023 Share Posted January 13, 2023 1 hour ago, Rawnei said: Side by side with CST186 it doesn't look huge, just a bit wider. 🫤 What was the tire pressure? Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 I spoke to a fellow Master owner (who's not on this forum) who says both his stock CST186 and later a Pirelli tire (possibly Angel he didn't recall) that he changed to both jumped off the rim! Are we looking at potential problem with Master rim here? Do we have more experiences like this?! I compared the S22 tire with the CST186 just now, they have very very similar dimensions, difficult to spot differences with my bare eye, I measured the inside dimensions of the side walls and they differ like 2mm only. Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 (edited) Yet another rider, Franco on telegram, known rider with a lot of contacts in the industry, he had CST186, Michelin Pilot Street and Shinko 244 jump off his rim! Edited January 14, 2023 by Rawnei Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 Re: Tire Pressure, I myself was using 45 PSI, fellow local rider had tires pop at 45-50PSI, Franco tried different PSI's between 20-38 on 3 different tiers and still tires popping off so it doesn't seem dependent on tire pressure, more witness accounts and experiences would be welcome, potentially this is a big issue. Quote Link to comment Share on other sites More sharing options...
Cerbera Posted January 13, 2023 Share Posted January 13, 2023 (edited) Damn. Sorry you had to crash to discover this ! But if this is a problem endemic to every Master I am surprised that we haven't heard about a LOT more instances of it happening already. There are quite a lot of Masters in the world at the moment, and we seem to have just 3 machines (is that right) out of all those many hundreds, whose tyres have popped off ? I mean I appreciate that's 3 too many, but see what I mean ? People have been changing tyres all over the place on that wheel, and I am curious that we are only hearing about pop-off events now... Edited January 13, 2023 by Cerbera Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 Measured the inside of the rim that is supposed to hold the tire, I don't have anything to compare with but it seems very small, only 7mm: Just now, Cerbera said: Damn. Sorry you had to crash to discover this ! But if this is a problem endemic to every Master I am surprised that we haven't heard about a LOT more instances of it happening already. There are quite a lot of Masters in the world at the moment, and we seem to have just 3 machines (is that right) out of all those many hundreds, whose tyres have popped off ? I mean I appreciate that's 3 too many, but see what I mean ? I got two witness accounts just minutes from mentioning what happened to me, seems people are not saying anything about this. Quote Link to comment Share on other sites More sharing options...
Cerbera Posted January 13, 2023 Share Posted January 13, 2023 1 hour ago, Rawnei said: I got two witness accounts just minutes from mentioning what happened to me, seems people are not saying anything about this. But why have they not mentioned it I wonder ? - that's a fairly big thing to happen !! Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 Just now, Cerbera said: But why have they not mentioned it I wonder ? - that's a fairly big thing to happen !! Yes it is, that's why it's important more people share their experiences if this is a widespread thing. 1 Quote Link to comment Share on other sites More sharing options...
Cerbera Posted January 13, 2023 Share Posted January 13, 2023 Did you lube the rim when you installed the KS tyre at all ? Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 1 minute ago, Cerbera said: Did you lube the rim when you installed the KS tyre at all ? No. Quote Link to comment Share on other sites More sharing options...
supercurio Posted January 13, 2023 Share Posted January 13, 2023 (edited) I measured the S22 rim lip for comparison and here's what I got: The lip has a transition which looks like a fillet, starting at 7mm. Then the full depth from the top of the lip to where the tire rests is 10mm. There's two more transition / fillet which rounds the lip altogether on its top. Edited January 13, 2023 by supercurio 1 Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 Here's the Master one, recess is 7-8mm where tire rests, rim is 38mm wide between walls. Quote Link to comment Share on other sites More sharing options...
Meserias Posted January 13, 2023 Share Posted January 13, 2023 do this happens to some of you using Kenda 340a ?? I'm keeping ~37psi (I'm making no jumps whatsoever !) Quote Link to comment Share on other sites More sharing options...
FlyboyEUC Posted January 13, 2023 Share Posted January 13, 2023 This happened to me on a V1 Sherman rim with a IRC N77 80/90-14. Luckily the tire valve popped out so I was able to deflate the tire normally. I was going same speed as you and slightly uphill at 40 psi. I didn't know what was happening though and lifted up the wheel. The board popped 2 seconds later trying to balance the wheel. I installed the V2 rim (wider) and the same tire. I haven't had any issues since. I have treated tire changes differently since then. I still don't really know why it happened. Quote Link to comment Share on other sites More sharing options...
supercurio Posted January 13, 2023 Share Posted January 13, 2023 (edited) 1 hour ago, Rawnei said: Here's the Master one, recess is 7-8mm where tire rests, rim is 38mm wide between walls. 2-3mm is enough to make the tire fit secure or loose I suppose. The total diameter of the S22 rim, lip to lip is 373 - 374mm also (best I can measure with the rim on the motor).OG Sherman V2 rim: nearly the same at ~374mm Is it less on the Master? Edited January 13, 2023 by supercurio Quote Link to comment Share on other sites More sharing options...
Funky Posted January 13, 2023 Share Posted January 13, 2023 Maybe to high PSI? Can't that be a problem also? Bigger tires normally need less PSI. (If i'm not wrong..) Then again i'm a 2x weight of a normal person - riding only at 30psi.. Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 From Facebbook: Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 1 hour ago, FlyboyEUC said: This happened to me on a V1 Sherman rim with a IRC N77 80/90-14. Luckily the tire valve popped out so I was able to deflate the tire normally. I was going same speed as you and slightly uphill at 40 psi. I didn't know what was happening though and lifted up the wheel. The board popped 2 seconds later trying to balance the wheel. I installed the V2 rim (wider) and the same tire. I haven't had any issues since. I have treated tire changes differently since then. I still don't really know why it happened. I wonder if I have v1 of the rim even although I have Master V2, entirely possible with all their mismatch of parts. 1 hour ago, Funky said: Maybe to high PSI? Can't that be a problem also? Bigger tires normally need less PSI. (If i'm not wrong..) Then again i'm a 2x weight of a normal person - riding only at 30psi.. Already been established that people had the same problem at different tire pressures. Quote Link to comment Share on other sites More sharing options...
Stevebee Posted January 13, 2023 Share Posted January 13, 2023 How many incidents were with the stock tyre? Some of the tyres mentioned are mc tubeless tyres which, although a number have been successfully installed, maybe it’s a closer tolerance to keeping on the rim. My initial thought was maybe too much soap used when installing but that’s been ruled out. A mystery Quote Link to comment Share on other sites More sharing options...
Rawnei Posted January 13, 2023 Author Share Posted January 13, 2023 (edited) Edited January 14, 2023 by Rawnei 1 Quote Link to comment Share on other sites More sharing options...
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