wheel suspect causing punctures

sandbag
sandbag Posts: 429
edited January 2010 in Workshop
First time out with a Shimano R500 rear training wheel and I have 3 blowouts. Within 100 yards of setting back from 40 miles, i have a blowout. Check the tyre thoroughly. Nothing. So i inspect the wheel, looks fine. Can't pump up the punctured tyre as it too bad, but can't find the puncture either strangely. So i fit a new tube. 5 mins later, bang same again. Can't find the puncture,I check the spoke tension, no loose spokes. What i notice is the plastic rim tape has slipped slightly and there's abit of exposed spoke hole next to where the valve is. So i slide the rim tape back into place and put some tubing there for extra protection. The punctured inner tubes look fine around the valves. I have no choice but to fit another tube but this time i pump it up even less. Bang again 1 mile on. So i had to call for help and get a lift home.

Earlier to top it off, the SPD cleat bolts had come loose and lost on one shoe. so pedalling was slippy. lol

Now the conditions were high blasting sub zero cold winds, so i couldn't take my time to examine all in detail and still haven't yet but will tomorrow. I was just glad to be home in the end.

My thoughts are i had no puncture for 40 miles and then suddenly get 3, so probably a loose spoke being a new wheel? The loud crack sounds to me like it could be a spoke puncture. The thing is the plastic rim looks pretty tough to stop that and the spokes were tense. I had inflated to 110PSI before setting off but later inflated with lesser amount using hand pump. I am puzzled.

Sorry for the long tale. The moral of the story is don't go far on a new wheel, especially in cold conditions.

So until i examine properly tomorrow, i like to hear your thoughts on R500 and using plastic rim tape. Should i replace it anyway, with a cloth variety?

Thanks.

Comments

  • Wamas
    Wamas Posts: 256
    Double check your tyre again to make sure these isn't a thorn or something in it. It isn't always that easy to spot when you are out on the road.

    I had this recently, first time out on a new winter wheel with the club and I punctured, thought the rim tape had slipped and that was what caused it, so fitted a new tube after adjusting the rim tape, everything was fine. Then when I got home, I took the tyre/tube off to properly fix the rim tape, and found a very small thorn in the tyre which I hadn't spotted at the road side, as I had convinced myself the puncture was caused by the slipped rim tape. Thankfully the thorn hadn't punctured the second tube.

    Alternatively, the first puncture may just have been bad luck, and in fitting the other tubes, you have let a bit of grit in. Take the tyre off, turn it inside out and give it a good clean inside with clean hands or a clean cloth.

    Velox cloth rim tape is pretty good, but I doubt it is the rim tape causing the problem, if you made 40 miles in the first place.
  • amaferanga
    amaferanga Posts: 6,789
    A loose spoke won't cause punctures. The only way a spoke can cause punctures is if the rim tape gets pushed over (something that can happen as you're putting the new tube in) or if the spoke is too long for the wheel and punctures the rim tape then the tube.

    If you find the holes in the punctured tubes you should can work out what caused the punctures.

    My guess would be that you trapped the tube between the rim and tyre as you put the tyre on (at least for the two replacement tubes). This would usually puncture as you pumped the tyre up, but could also puncture after a few minutes riding.

    FWIW I use plastic rim tapes without any problems.
    More problems but still living....
  • sandbag
    sandbag Posts: 429
    Thanks for the replies.

    I got the same blowout pop sound puncture on 2 and 3 as i did 1. The wheel has altered or the plastic rim tape has slipped after 40 miles to get all punctures close together.

    I examined it today. The puntures took some finding. There are 2cm slits parallel with the tube. The wheel is fine apart from small chunks out of the rim on 1 part. This could be due to riding on the rim after each blowout. There is a tiny slight raised knick or twist at the side of the plastic rim tape. I do believe this is what caused the punctures. I can't find another reason.

    First time out. Hate plastic rim tape. :twisted:
  • rake
    rake Posts: 3,204
    pinch flats. tube caught under tyre .
  • Next time, pump the tyre up to about 10psi, then rock the tyre back and forth. This a. seats the tyre on the rim, and b. stops the tube being caught in between tyre and rim.
    When pumping up, keep an eye on each side of the tyre. If you see the tube coming out, let the air out immediately. I'm a bike shop mechanic and have seen and even done it myself loads of times.
    jedster wrote:
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    FCN 3 or 4 on road depending on clothing
    FCN 8 off road because I'm too old to go racing around.
  • sandbag
    sandbag Posts: 429
    Correction 1cm slits. The slits are in the inside middle.

    I run my finger down the plastic rim tape and the knick feels abit less than sharp. enough to cause some wear. I am suspicious I had a few wheels but first time with this plastic tape. I am going to switch to trusted Velox for peace of mind.

    Nothing in the tyre for sure. I examining the tyre again and it is alittle worn down the sides. I am going to get a better tyre than this wired Continental UltraSport, although not had it long.

    I am feeling the pain going through 7 tubes in 3 weeks for different reasons.

    I will pay more attention to seating it correctly. Looking back i changed them at speed due to survival. but i still think i would of got the punctures if i took longer time.

    Thanks for the advice.

    On a happier note, I am happy with the wheel, lol. It is sturdy strong.
  • sandbag
    sandbag Posts: 429
    Got a new tyre. The Bontrager Race Lite Hard Case. Comes with triple puncture protection. It is a very tough tire.

    http://bontrager.com/model/00443
  • dennisn
    dennisn Posts: 10,601
    Not sure if someone mentioned the tire slipping off the rim(not seated properly).
    This can and does happen on occasion. Have also heard a story or two about
    defective or torn tire beads. When a tire bead slips off of a rim the tube explodes
    with a good sharp bang(personal experience).
  • John.T
    John.T Posts: 3,698
    Are there any splits in the tyre sidewall that could be caused by a brake block being too high and rubbing through. I have also known these to be caused by rough edges on the inner face of the rim wearing the tyre just above the wire as the tyre flexes. This happened to me and a clubmate a few years ago with cheap Mavic rims ( I can not remember which).
  • sandbag
    sandbag Posts: 429
    edited January 2010
    I am new to this kind of puncture and not used to the shallower rim in awhile. You can understand me thinking it's the wheel first time out with it.

    Thanks for the probable helpful theorys. Now it could be the tyre after all. I don't see any splits inside or out. It could of worn away the tube and the rim helped it etc. I am pretty sick of the whole episode, but i dig out the tyre and have a further look. Maybe you only see a tiny splt at high pressure. I see the tube gets caught easily at high pressure in the tiny split right.

    I been thinking for the price of all the tubes and tyre. I could of bought a R500 front as well. In fact Planet-X are doing a pair for £80. But it more likely the tyre now, so i don't feel as bad hmmm.

    I am going to try 90PSI . This new Bontrager is a better faster ride. I feel like i'm gliding along more. It meant to prevent pinch flats. This tyre is going to last through Winter and stop punctures dead. I just know it. Impressed with this tough tyre. Problem solved.

    My rear brake pads are not rubbing against the tyre in the slightest. Funnily enough i bought this older 105 discounted front brake. http://www.chainreactioncycles.com/Mode ... elID=13603 Now it 49mm drop but the brake pads touch the tyre by 1-2mm. The only way i could see to solve this was to file away the brake pad holes alittle, so the brakepads sit lower. I filed at the same made angle so it wouldn't affect the angle of the pads. Did i do right?
  • desweller
    desweller Posts: 5,175
    To save yourself a bit of dough, try patching the tubes instead of discarding them.
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  • sandbag
    sandbag Posts: 429
    Yes just slits are harder to patch. I need more better glue. I always run out of glue before i use up all the patches. The tube i got had raised seams, so patching a wide cut on a seamed tube needs extra care. Have all tubes got lined join seams?

    I was advised not to patch the front because it increases failure risk. If you have a high speed blowout at front, you more likely to be badly injured.
  • balthazar
    balthazar Posts: 1,565
    sandbag wrote:
    I was advised not to patch the front because it increases failure risk. If you have a high speed blowout at front, you more likely to be badly injured.
    I don't know who is advising you. A properly patched tube is as reliable as new; if you don't trust it then you won't want it in your rear tyre either.
  • desweller
    desweller Posts: 5,175
    sandbag wrote:
    I was advised not to patch the front because it increases failure risk. If you have a high speed blowout at front, you more likely to be badly injured.

    Nonsense. I've never had a patch fail. If you apply them correctly then there will be no issue.

    It's not the bloke from the LBS is it? He's probably hoping to flog you some tubes.
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  • Wappygixer
    Wappygixer Posts: 1,396
    I've had patches fail a few times but always on Conti super sonics and patchedwith Park self adhesive patches.
    I've never had a proper vulkanised patch go wrong though.
  • John.T
    John.T Posts: 3,698
    I have never considered self adhesive patches to be more than 'get you home' jobs. A proper vulcanised one, if fitted correctly, is permanent and safe.
  • Slits could be caused by the rim tape not covering the holes on the inside of the rim where the spokes fit in. I had this problem once. Fond de Jante rim tape rules.
  • sandbag
    sandbag Posts: 429
    balthazar wrote:
    sandbag wrote:
    I was advised not to patch the front because it increases failure risk. If you have a high speed blowout at front, you more likely to be badly injured.
    I don't know who is advising you. A properly patched tube is as reliable as new; if you don't trust it then you won't want it in your rear tyre either.
    DesWeller wrote:
    sandbag wrote:
    I was advised not to patch the front because it increases failure risk. If you have a high speed blowout at front, you more likely to be badly injured.

    Nonsense. I've never had a patch fail. If you apply them correctly then there will be no issue.

    It's not the bloke from the LBS is it? He's probably hoping to flog you some tubes.

    Sure, it just sounded like a sensible idea to follow. Me thinks I need to upgrade my patch kit.

    I try to carry 2 tubes at all times. If get a puncture before dark i repair it, instead of fitting new tube. I want to avoid repairing punctures in the dark.

    Sure, you can patch so good it's invincible, as strong as the tube itself kind of. Just recently i done some bad patches. I let the glue dry good but they just peeled off after alot pressure. It took 3 attempts. It was the last of the glue, made me question the quality of the patch kit. Although vulcanization doesn't happen in cold temperatures, maybe thats the problem. I going to change to a different brand just to see.
  • sandbag
    sandbag Posts: 429
    Slits could be caused by the rim tape not covering the holes on the inside of the rim where the spokes fit in. I had this problem once. Fond de Jante rim tape rules.

    The rim tape will of slipped or is very thin if that's the case. Sounds like you was using too thin for your rim. You get the nearest width for your rim. I am using 17mm. The plastic and cloth rim tape i've used has covered the whole width and is stuck or tightly packed down. They both so tight down, i cannot see how they could crawl up the sides either.

    The punctures from spoke holes i've had, were kind of star shaped. I am more inclined to think for now, that there was a tiny split in the tire, which would create a sharp edge against a high pressure tube. I checked the wheel rim and it smooth.

    I had dug the old tyre back out the bin. I put a tube in and pumped it up. At 50 PSI i hear this loud bang. What now??? A small part of the tyre had exploded outwards, there was a shredded hole. I had made sure, i hadn't trapped a part of the tube on the outside.
  • sandbag
    sandbag Posts: 429
    Well i have done 3x60 mile rides from Friday, had 1 tiny puncture from the new tyre. :twisted: , due to embedded glass. There is 3 cuts and a 1/2 inch slash. The kevlar has stopped the rest of the glass. There is now a slight wobble on the new wheel, sigh. But I have managed to dodge the mountains of leftover grit.

    It seems, no tyre is safe if they can get through this.

    At this rate i be better off switching to a MTB bike.
  • desweller
    desweller Posts: 5,175
    Crikey, it sounds like you're riding through a glass recycling bin! Good work on the mileage, 180 miles in less than a week is good going (well it is by my paltry standards).

    Don't get too disheartened. Sometimes you just get spates of 'em. Round here, it always coincides with farmers clipping their hedges. I got two, one in the rear, one in the front, just cycling to work once (a grand total distance of 6.5 miles!).
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  • sandbag
    sandbag Posts: 429
    A further 220 miles on same route and no punctures on the Bontrager Hard Case. So yes as you say punctures do seem to come in spates. I did have a puncture on the now worn Continental Ultra Sport front though. It has been a very quick wearing tyre for me. I should of got something hardy from the beginning, for training and Winter.

    Thanks for the comments of solace.