vmeldrew Posted January 9, 2011 Report Share Posted January 9, 2011 I am slowly getting my bike into a condition where I will have to stop blaming it and have to admit I cant ride...... But in the meantime, I took the plunge and bought a set of Michelin tubeless tyres to replace the rather rotten front and the not so knobbly rear. This after selecting first in some snow last week and the bike not even moving, wheelspin from a standing start, not too impressive. Got the old rubber off without too much hassle, tubes, typical. After reading here I was guessing that I am in for a treat, cleaning the rims, sticking down the rim tape and who knows what else. Decided to try without changing the rim tapes, afterall they looked pretty much foscilised into place. Back first put in a new tubeless valve and wahey it jumped straight onto the rims, but its leaking around the valve. Would you suggest keep tightening the valve and risk it snapping off or start again, new rim tapes with silicon or something over the spokes? Do I need to put any goo around the valve? Also tried the front, there is a security bolt and most of the wind was escaping around that. I managed to seal it with a bit of old inner tube to get beads on but its leaking arounbd the bolt. This got me wondering, do I need a security bolt or not? If I do how do I go about stopping the leak if not, what do i fill the hole with? Thanks in advance. Al Quote Link to comment Share on other sites More sharing options...
pumpkin trials Posted January 9, 2011 Report Share Posted January 9, 2011 Your front should not be leaking at all unless you have nipped the tube putting the front tyre back on, it may just be forcing whats left between the tyre and tube. Did you slacken the security bolt before taking the old tyre off, it should be pushed almost back into the rim so that the edges catch the rims of the tyre and pull them home when you pump it up. After that you can lock the nut off and another tip is to leave a bit of play in the valve lock nut to allow the valve a bit of movement. As for the back the best bet is take the tyre of and by a tube of good quality silicone or sicoflex that is used around car windows, clean the area where the rim tape bites into the rim to make sure they are clean and then dab the top of each spoke and around where the valve goes. Get the tape back on and seated and run a bead around each side where it seats into the rim. Put the tyre back on and get her back out on the beads and put about 60 = 80 psi in for an hour or so, this puts pressure onto the tape which in turn forces the goo around the spoke nipples thereby sealing each nipple. This should sort you out Quote Link to comment Share on other sites More sharing options...
coriolis Posted January 9, 2011 Report Share Posted January 9, 2011 First off...the front isnt tubeless! All front rims run tubes ! The rear can be a little more tricky. I certainly advise against using any kind of sealant. Im theory it should work, but in practice all it does is create a huge mess to clean off when it still wont seal! If you have an old horrible looking rim tape, i advise replacing it. I believe the new type tapes have the valve built in, which help a great deal with leaks. I used to have a bit of a reputation amongst some riders in the SSDT padock for being able to seal rim tapes quite well. My best advice is to clean the rim, it must be spotless mind, then use a good tacky chain lube all around the well of the rim, and on the rim tape itself. The chain lube is applied with a solvent carrier that evapourates after a short time, leaving the tacky lube behind. What this does is allows the tape to be evenly stretched around the rim whilst it is still quite runny. As the solvent evapourates, the lube goes tacky and helps create a good seal between the rim and the tape. Its a messy job, but once its done, and the bead it cleaned off, it tends to work extremley well. The problem with using silicon etc, is that if it is disturbed, the seal is broken (and it always gets distubed). Tightening a spoke usually ruins the seal if you use silicon. Also, rusty spoke nipples (on the inside of the rim) can cause problems. Hope this helps! Quote Link to comment Share on other sites More sharing options...
jse Posted January 9, 2011 Report Share Posted January 9, 2011 Decided to try without changing the rim tapes, afterall they looked pretty much foscilised into place. Back first put in a new tubeless valve and wahey it jumped straight onto the rims, but its leaking around the valve. Would you suggest keep tightening the valve and risk it snapping off or start again, new rim tapes with silicon or something over the spokes? Do I need to put any goo around the valve? Also tried the front, there is a security bolt and most of the wind was escaping around that. I managed to seal it with a bit of old inner tube to get beads on but its leaking arounbd the bolt. This got me wondering, do I need a security bolt or not? If I do how do I go about stopping the leak if not, what do i fill the hole with? Thanks in advance. Al The leaking around the valve is probably due to the washer/band on the backside not sealing. You could try tightening it but that depends on how lucky you feel. I'd take the tire off and find out what the problem is. If the back tire leaks on a regular basis, you will not enjoy riding the bike. There is not much pressure in the back tire so if it's leaking, so I'm guessing it's a mechanical problem with the washer/rim band. You may not need to replace the band if it's in fair shape. I like to store my bike with 30 psi in the tires as I think it helps to force moisture out of the bead area and keeps the band tight against the rim. I've not had a leakage problem in 9 years. On the front tire, the leakage from the rim lock is the secondary problem and leakage from the tube is the primary issue. You (if it's a new tube) probably pinched the tube putting it in. When levering the tire bead on the rim, if you go past vertical with the tire lever you stand a very good chance of pinching the tube against the inside of the rim. Take shorter "bites" of the tire bead to lever it on and push on the bead (the part that is already inside the rim) to roll it on the rim rather than just lever pressure. Unless you never use your front brake, you will not need a front rim lock (just kidding, yes, you need the rim lock). Jon Quote Link to comment Share on other sites More sharing options...
vmeldrew Posted January 9, 2011 Author Report Share Posted January 9, 2011 First off...the front isnt tubeless! All front rims run tubes ! DOH! - Well nobody told me that one and it certainly wasnt in the instructions that came with the tyres.... Top skills though getting it on the rims without one! maybe I could start a new trend? If tubeless is that much better for grip and feel, so i have read, why use a tube in the front? Why make a tubeless tyre? As for the rest of the comments, they all make perfect sense, its a simple matter of physics in the end. It won't leak if the air can't get out! Jon, I am liking the 30psi for storage idea. Al Quote Link to comment Share on other sites More sharing options...
jse Posted January 10, 2011 Report Share Posted January 10, 2011 DOH! - Well nobody told me that one and it certainly wasnt in the instructions that came with the tyres.... Top skills though getting it on the rims without one! maybe I could start a new trend? If tubeless is that much better for grip and feel, so i have read, why use a tube in the front? Why make a tubeless tyre? As for the rest of the comments, they all make perfect sense, its a simple matter of physics in the end. It won't leak if the air can't get out! Jon, I am liking the 30psi for storage idea. Al See Al? Ya learn something every day Actually, they tried the tubeless front tire, on some of the Fantic's, possibly the 309 model as I remember. It didn't work very well and in a muddy, wet Trial you were fairly well assured of the tire slipping completely off the rim. My guess is that the twisting of the tire casing caused by normal steering changes worked water in between the tire bead and rim, which then acted as a lubricant to allow the tire to roll off the rim. Jon Quote Link to comment Share on other sites More sharing options...
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