So I got new wheels, Reynolds Carbon Assault with the PT. They are 21.6mm wide and I use 23mm tubes and the continental gp4000s tires. I have had these new wheels for about 3 months and to date have had 4 flats on the rear and one flat on the front tire. I have examined and re-examined the tape on the wheel and I don’t see an issue and cant feel any sharp edges, spokes penetrating through the tape, etc. I always check the tube after installing to make sure it isn’t pinched (more so after the first two flats) by going around on both sides and all is good. I believe that for the majority of the time I flat after some impact going in a pothole or some type of bump in the road. However, I have ridden the same roads with Ultegra wheels and similar tubes and tires and probably have flatted more in the last three months with the Reynolds than I have with the Ultegra wheels in the last 4 years. I am at a loss and not sure if its something with the carbon wheel? Is it the width (too narrow) and the tube is not properly seated? Also I always check that the tires are properly inflated at 110 psi. Any ideas?
What kind of puncture does it look like on the tube? snake bites?
Is it possible your psi gauge is not working properly, and you’re not actually running 110 psi?
Where are the punctures happening on the tube? middle or off to one side?
So the last two flats I kept the tube and checked where the puncture occurred. The last rear flat was a single puncture towards the bottom. The flat just this weekend was my first front flat and it is two puntures, ie snake bite. I think the gauge is okay but can’t be sure. A finger pinch test of the tire feels about right but can’t be sure. Again though, have been using the same pump for a while. Why havent I had this issues with the Ultegra. Even if it 100 psi, how likely would that be the reason.
The ultegra wheels may behave differently because the rim shape is different, specifically the internal width of the rim where the tire’s bead rests.
It could be you have two issues, but the snake bite on the front sounds like you hit really hard and/or the pressure is too low.
What do you weigh?
I weigh 160 lbs. I am thinking it has to be something with the rim shape or something. I just never had so many flats in such a short duration. Its a mystery that I want to solve soon so that I don’t have to worry during races. As it is, it seems that at most every four rides or so I get a flat, maybe even sooner.
At 160#, 110 psi should be more than enough. I would check your pressure gauge.
+1
if the holes in the tubes are on the rim bed side, just replace the rim tape. sometimes cheap rim tape will deform and shift under the high pressure of the tube and allow the edges of the rim holes to directly contact the tube.
if the holes are on the tread area of the tube/tire interface, feel the inside of the tires for wire or glass poking through (I have picked up bits of wire in both tires and not caught it either)
if you are riding on rough roads, is there a chance you are pinch flatting? look for pairs of holes on the sides of the tubes.
rich
So the last flat is a front tire flat with two holes, ie pinch. I recall going over a pothole but I have gone through so many in the past without flatting. I pumped the tire up before the ride and felt the pressure, it was hard so it may not have been exactly 110 but it wasnt significantly lower. At every flat I felt around the entire inside of the tire and wheel for any foreign objects, glass, anything and never found anything.
Don’t waste your time feeling around. Take the tire off all the way, turn it inside out, bring it someplace where the light is really good and visually inspect every part of the inside of the tire carcass. Flex it around so that you can see if there are gaps in the cords that could be hiding a glass or metal fragment. Before you put the tire back on the rim look at the rim tape and the inside of the rim the same way. This way you’ll also be sure you’ve got any crud that might have been floating between the tube and tire, out of there.
Put it back together, making sure the tube never gets pinched between the rim and the tire bead at any time. And no using tire levers!
I’m sure there will be strong opinions from those that love them, but I absolutely HATE the Continental GP4000s for training. I temporarily switched to them this spring and went through a stretch of about 11 flats over the course of a month where I did not go more than 50 miles on them without flatting. Granted, the roads here in NJ/PA were horrible this spring, but I found the Contis to be really lacking in durability. Worst run of flats I ever had…maybe coincidence, maybe not, but it really sucks when you go through both your spare tubes in one ride and wind up flatting again. Mostly sidewall cuts but a couple straight puncture flats as well. Save the Contis for race day if you must but I will likely not ride them ever again. I just cut my losses and switched to the Vredestein Fortezza Tricomps for training rides…the things are bulletproof. For racing I’m on either Zipp Tangente or Vittoria Evos.
So we have established that the front tyre was a pinch flat - likely no issue with the tyre. Perhaps it was just a weak tube (they happen) that lost some air during the ride.
Rear wheel sounds like either the rim tape needs replacing, or there is something unseen/felt imbedded in the tyre
And so after about two flats in the rear I swapped tires with a brand new gp4000s ii and still kept getting flats.
Hmmm, guess then it can only be something in the rim / tape…
Are you replacing with new tubes each time?
Maybe try a different brand tube.
Lots of good advice. Sometimes it’s just bad luck. The single puncture toward the bottom sounds like a thorn. It’s Goat-head season around here.
My wife had flats on both of her first two races this season. With an IM coming up I didn’t want her worrying about anything so we put Gatorskins on. A ton of training miles and two IM’s later not a single flat. I’m a believer.
I’m sure there will be strong opinions from those that love them, but I absolutely HATE the Continental GP4000s for training. I temporarily switched to them this spring and went through a stretch of about 11 flats over the course of a month where I did not go more than 50 miles on them without flatting. Granted, the roads here in NJ/PA were horrible this spring, but I found the Contis to be really lacking in durability.I agree. Even though it’s not really a big deal, flatting is the ultimate buzzkill while riding. I’ll happily give up 25-50g for a tire that offers improved protection. I’ve found the GP 4000s tire handles brilliantly and rides smoothly but is nowhere near the durability of a true training tire. It’s particularly cut-prone as well due to the very high TPI. It is meant to be a racing tire, afterall.
I’ve had very good luck with bead-to-bead Kevlar, 60TPI or 120TPI tires. There are lots of options and tires like this are much more flat and cut resistant than the 4000s. You don’t need to spend a lot, the best puncture resistant training tires I’ve tried are the Nashbar Duro Pro (rebranded Maxxis tires), which can be had for around $25.
So weird to read this thread as I am having exactly the same problem with a pair of Reynolds.
5 punctures (4 rear and 1 front) in less than 6 weeks. Rears are all in different places.
The last 2 (1 front and 1 rear) were after I had put gatorskins on. I have never ever had a puncture with gatorskins in my life so a bit mystified.
Put new rim tape on, used 3 different make of tubes and 3 different make of tyres. The front one was from hitting a pothole at speed that I missed in the shadow of a tree. No spokes poking through, no pinched tubes. Costing me a fortune in tubes!
I have the same Reynolds Carbon Assaults (with Powertap G3) and run GP4000S. I have had 3 flats in around 8,000 miles (about the same as normal). The first flat was in the drizzling rain on a century ride where everyone had flats. The next was a hard pothole which caused a pinch flat in the rear. The third was about 6 weeks later from the side wall being compromised from the pinch flat.
The wheels have been very reliable for me.
Maybe invest in some Velo plugs? Not a huge investment, and might remove one variable (spokes) from the equation?