ByronH Posted June 10, 2015 Share I'm 84kg, and I've started running my front tyre at 2 bar. Geax Saguaro TNT, on Fulcrum Red Metal Sl wheelset. Twice now, it has burped every little molecule of air out whilst riding at Heia safari, that the tyre sticks to the rim. After the first time I had it serviced, and thought all was good. And it was, if I did the Spruit. But I went back to Heia safari today, and it happened again! Even bombing it twice made no difference. Air just escaped out the rim. Not an issue of servicing or slime. And surely not an issue of 2 bar? Is it my floor pump that's innacurate? are my rims not suitable? Do I need to run a higher pressure? It's flippin annoying. Makes me want to stick bloody slime filled tubes in. Link to comment Share on other sites More sharing options...
Guest notmyname Posted June 10, 2015 Share Sounds strange man. I have a saguaro up front to and at a feathery 89kg(lol) no burps at 1.6 bar. I'll be following this. Link to comment Share on other sites More sharing options...
JXV Posted June 10, 2015 Share I burped a rear tyre three times on three consecutive rides climbing the same rocky step on the Clearwater Trails ride. Everywhere else that I ride...no problem. WTB Frequency i23 rim with Spez GC 2.3. This is a moderate width rim with beadhook. So it may just be one particular obstacle or rocks that are more grippy than where you normally ride. In my case higher pressure was the solution. If your rim is hookless and the tyre an easy fit on the rim it will burp easier...so maybe more pressure Link to comment Share on other sites More sharing options...
akneethling Posted June 10, 2015 Share I would say run 2.3 and if it still happens go higher until it stops. But it could be the Rim or the tubeless conversion. Incidentally. ....... what type of tubeless conversion do you have? Link to comment Share on other sites More sharing options...
ByronH Posted June 10, 2015 Share I would say run 2.3 and if it still happens go higher until it stops. But it could be the Rim or the tubeless conversion. Incidentally. ....... what type of tubeless conversion do you have?Thanks for all the advice guys. I am not sure if the rim is hooked, but it's a flipping mission to get the tyre on or off(three men and three broken tyre levers kind of mission). In terms of the type of tubeless conversion, I am not sure. The rims are tubeless ready, so they require rim tape and sealant if that answers your question? And yes, both times it has burped going down a steepish rocky track. Link to comment Share on other sites More sharing options...
ByronH Posted June 10, 2015 Share Sounds strange man. I have a saguaro up front to and at a feathery 89kg(lol) no burps at 1.6 bar. I'll be following this.Better check the accuracy of my floor pump as well Link to comment Share on other sites More sharing options...
Headshot Posted June 11, 2015 Share Tyres behave differently on different rims. Some tyres, those with more flexible sidewalls generally, fold over when cornering and can allow air to escape. Thee thinner the sidewall ( ie lighter the tyre, generally the more temperamental they are. Run proper tyres ie snakeskim/protection or whatever the Maxxis or Vittoria equivalents are and pump them up hard. The heavier you are, the harder. I am 83kg and run about 2 bar out back and 1.8 in the front on 2.35 all mountain/trail tyres on 23mm rims. No problems at all no matter what abuse I heap on them. Link to comment Share on other sites More sharing options...
RocknRolla Posted June 11, 2015 Share I would have the rim checked out by a knowledgeable wheelbuilder person, to make sure it's 100%Sounds weird to me, and as for the 2.3 bar on a front tyre...I would be very nervous taking that thing around a corner with such high pressure. The dodgy rim tape is also an option. Link to comment Share on other sites More sharing options...
Terence Hope Posted June 11, 2015 Share Sounds like it is not seated properly from the outset, and not a pressure problem.Deflate the tyres, pour a little soapy water around the rim and beading of the tyre, and pump it up to 3.8 / 4 bar to ensure it seats properly, but DONT ride it at that, leave it overnight and then drop the pressure in the morning. If it still happens after this, then the beading on the tyre may be a little damaged, but this should sort out your problem. Link to comment Share on other sites More sharing options...
Terence Hope Posted June 11, 2015 Share At your weight you should be able to comfortably run at 1.7 Link to comment Share on other sites More sharing options...
ByronH Posted June 11, 2015 Share Sounds like it is not seated properly from the outset, and not a pressure problem.Deflate the tyres, pour a little soapy water around the rim and beading of the tyre, and pump it up to 3.8 / 4 bar to ensure it seats properly, but DONT ride it at that, leave it overnight and then drop the pressure in the morning. If it still happens after this, then the beading on the tyre may be a little damaged, but this should sort out your problem. thanks, gonna give this a go. does the soapy water help with the seating, or is it for me to view the air escaping? Link to comment Share on other sites More sharing options...
DR ◣◢ Posted June 11, 2015 Share To me it seems like the bead may be damaged. The whole 3 men and broken levers thing comes to mind. A damaged bead will still seal but it will be easier to burp. Link to comment Share on other sites More sharing options...
V12man Posted June 11, 2015 Share thanks, gonna give this a go. does the soapy water help with the seating, or is it for me to view the air escaping?Helps to seat the tire - you can also use sealant for this - but you have to be QUICK..... Link to comment Share on other sites More sharing options...
ByronH Posted June 11, 2015 Share Tyres behave differently on different rims. Some tyres, those with more flexible sidewalls generally, fold over when cornering and can allow air to escape. Thee thinner the sidewall ( ie lighter the tyre, generally the more temperamental they are. Run proper tyres ie snakeskim/protection or whatever the Maxxis or Vittoria equivalents are and pump them up hard. The heavier you are, the harder. I am 83kg and run about 2 bar out back and 1.8 in the front on 2.35 all mountain/trail tyres on 23mm rims. No problems at all no matter what abuse I heap on them. Yup, the tyres I have are TNT, meaning the sidewalls are sufficiently reinforced. "The Geax TNT casing is made from a cloth that has 120 threads per inch -- quite supple by mountain bike standards. The sidewalls are also reinforced with nylon in order to minimize both cuts and folding when riding at low-pressure. Holding the tire onto the rim is a traditional folding Aramid bead." And a pattern i have noticed is that the rear tyre (at 2.1 bar) never burps, despite taking some heavy knocks. But the front tyre, on decents (and with a corner at the bottom), likes to burp. Link to comment Share on other sites More sharing options...
ByronH Posted June 11, 2015 Share To me it seems like the bead may be damaged. The whole 3 men and broken levers thing comes to mind. A damaged bead will still seal but it will be easier to burp. Yup, the first time the front tyre burped I was literally only 15 minutes into my ride, so I tried to take the tyre off to insert my spare tube. EISH! The tyre would simply not come off, and I broke two tyre levers. Then two guys stopped to help me. All three of us were then pulling and tugging at the tyre from different angles, and eventually, it popped off. Only after breaking another tyre lever. And then... to try and get the tyre back on... on my own.. was simply impossible. Linden Cycles had to put the tyre back on, and even they complained... Link to comment Share on other sites More sharing options...
jimmycool Posted June 11, 2015 Share It wouldn't be a bad idea to verify your pump pressure gauge as well. Link to comment Share on other sites More sharing options...
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