rbent Forum - Continental Gp4000sII

Phantom Rider

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Posts: 1056

Continental Gp4000sII
Apr 25^th, 2015, 6:53pm

I bought a set of 700x25 and now have 375 miles on them and love the ride and handling. The tire performs very well but...I have now had 3 flats on these tires. this is driving me crazy and I'm curious if anyone else is having issues. All three flats have been on the front wheel and I have checked over and over again to ensure there is nothing in the tire before mounting the new tube. The first occurred when I ran over a set of RR tracks and picked up a piece of metal, I could hear it hitting the ground on rotations so I knew I was in trouble, the tube was loaded with Flat Attack but the cut was to large to seal. #2 i discovered in the garage one morning before heading out to ride and #3 occurred on the road today, i picked up something and heard it instantly but again nothing in the tire.

Flats 2 &3 occurred with performance light tubes of which I haven't used before. They were on sale 4 for the price 3 when I bought the Reynolds wheels and I didn't have any 60mm tubes with me.

I HATE FLATS

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aikigreg Moderator recumbent ninja Posts: 3685	Re: Continental Gp4000sII Reply #1 - Apr 25^th, 2015, 9:25pm I've had flats with mine, but not that many. I've used them exclusively for at least 5 years on every single bike I own.
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rmillay Five Star Member rbent member; go Clowns! Posts: 2180	Re: Continental Gp4000sII Reply #2 - Apr 26^th, 2015, 6:35pm Wet roads increase the frequency of flats.
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Phantom Rider

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Re: Continental Gp4000sII
Reply #3 - May 1^st, 2015, 8:46pm

Another flat today on the front, thats now 4. This is really weird, I rode 33 miles this morning and no indication of flat, walked back into the garage this afternoon and felt the tire, it was soft. checked the pressure and found 40psi in it(down from 110 at ride time), pumped it up and checked again about 6 hours later to find it back at 40psi.

I have gone over and over this tire and find nothing in it. When i remove the tube, put some air in it and leave it setting in the garage it holds air.

come on folks somebody tell me whats going on here cuz its driving me nuts and i"m tired of going through tubes. The couple of tubes that have actually flatted have been out the exterior of the tube so no rim tape issues, the valves seem to be solid and no leaks around them.

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jrob_bent

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Re: Continental Gp4000sII
Reply #4 - May 1^st, 2015, 9:01pm

Quote from Phantom Rider on May 1^st, 2015, 8:46pm:

Another flat today on the front, thats now 4. This is really weird, I rode 33 miles this morning and no indication of flat, walked back into the garage this afternoon and felt the tire, it was soft. checked the pressure and found 40psi in it(down from 110 at ride time), pumped it up and checked again about 6 hours later to find it back at 40psi.

I have gone over and over this tire and find nothing in it. When i remove the tube, put some air in it and leave it setting in the garage it holds air.

come on folks somebody tell me whats going on here cuz its driving me nuts and i"m tired of going through tubes. The couple of tubes that have actually flatted have been out the exterior of the tube so no rim tape issues, the valves seem to be solid and no leaks around them.

That's why I use only Schwalbe Marathon Plus or Marathon Supremes. Yeah, I know they are suppose to be heavy, but what good is a lighter tire if it stays flat? I have close to 2,000 miles on the Plus, and got over 8,000 on the Supremes. NO FLATS! Wires sticking out of them, glass cuts, all kinds of stuff, but no flats. Seems pretty fast to me also.

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I get about 15 miles per honey bun!

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johnnybent

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Re: Continental Gp4000sII
Reply #5 - May 2^nd, 2015, 12:34pm

I have also had the plague of flats this week....same tire and front wheel, which is unusual on the xstream. Like you I could not locate a source of the problem (holes in different locations in the tubes) except the Rim tape was a little thin. Last night I replaced the tape in the hope that may help.. I just finished a 35 miler down to Mesquite and back up through Garland, no flats. Soooo....maybe.

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reever

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Posts: 459

Re: Continental Gp4000sII
Reply #6 - May 2^nd, 2015, 4:43pm

Here's something I learned from my local bike shop owner. Always arrange it so that the valve stem is in line with a letter on the tire--say the "S" in Schwalbe, or the "C" in continental. When you pull the inner tube out for inspection after having a flat, leave the valve stem in the tire and put air in it while it is still in place, making sure the tire doesn't move as you add air. Check for where the hole is by moving your ear over the tube. When you have found the leak, let all of the air out of the tube and let it go back to its normal size and match it up with the tire. You will know exactly where the shard of metal is in that tire. It works!
I absolutely HATE flats, so I am a believer in Schalbe products. Sure they are heavier, but I've found that often they have a lower rolling resistance than some other softer, lighter tires, and they certainly do a better job of smoothing out chip seal than those skinny 115lb/sq.in. tires do.

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aikigreg Moderator recumbent ninja Posts: 3685	Re: Continental Gp4000sII Reply #7 - May 2^nd, 2015, 5:20pm There must be a flaw with the tire or something. a burr of some kind on the rim? You could try mounting a different tire on that rim, or switch front tire to back to see if you get the same effect.
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rmillay Five Star Member rbent member; go Clowns! Posts: 2180	Re: Continental Gp4000sII Reply #8 - May 2^nd, 2015, 5:41pm Perhaps someone has put a curse on it.
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jayg

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Re: Continental Gp4000sII
Reply #9 - May 2^nd, 2015, 5:49pm

Joe, this is my take on the mystery: The lite tubes you are using are light, because they are thinner than standard duty tubes. Thinner means they are more permeable. When you inflate them outside of a tire they have a max internal pressure of about 4 psi. When you inflate them inside a tire they have a pressure of 110 psi. The higher the pressure the faster they leak down, due to their high permeability. Lite tubes just don't hold their pressure like standard tubes do.

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Phantom Rider

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Posts: 1056

Re: Continental Gp4000sII
Reply #10 - May 2^nd, 2015, 7:10pm

I'm thinking the mystery may be solved. With all my frustration i was doing research on tubeless and pulled my front wheel(flat prone) and took it over to bonzai to the bike whisperer(Brian). after much discussion, mounting and unmounting of the tire a small cut was observed on the tire. The cut was all the way through the tire, so we put a boot in the tire and will see if that solves the problem over the next few days.

BTW, my wheels are not tubeless capable so i will order a new tire soon just in case to be on the safe side. there are to many positive reports on these tires for me to give up, the ride and handling are great.

Thanks for all the education you have provided, ill keep you posted.

I was beginning to think bob was right.

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aikigreg

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Posts: 3685

Re: Continental Gp4000sII
Reply #11 - May 2^nd, 2015, 7:44pm

If you want a23mm tire I have one I can give you. Still has plenty of miles left.

Quote from Phantom Rider on May 2^nd, 2015, 7:10pm:

I'm thinking the mystery may be solved. With all my frustration i was doing research on tubeless and pulled my front wheel(flat prone) and took it over to bonzai to the bike whisperer(Brian). after much discussion, mounting and unmounting of the tire a small cut was observed on the tire. The cut was all the way through the tire, so we put a boot in the tire and will see if that solves the problem over the next few days.

BTW, my wheels are not tubeless capable so i will order a new tire soon just in case to be on the safe side. there are to many positive reports on these tires for me to give up, the ride and handling are great.

Thanks for all the education you have provided, ill keep you posted.

I was beginning to think bob was right.

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I'm in it to Schwinn it.

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Phantom Rider

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Posts: 1056

Re: Continental Gp4000sII
Reply #12 - May 11^th, 2015, 7:59pm

Quote from aikigreg on May 2^nd, 2015, 7:44pm:

If you want a23mm tire I have one I can give you. Still has plenty of miles left.

Quote from Phantom Rider on May 2^nd, 2015, 7:10pm:

I'm thinking the mystery may be solved. With all my frustration i was doing research on tubeless and pulled my front wheel(flat prone) and took it over to bonzai to the bike whisperer(Brian). after much discussion, mounting and unmounting of the tire a small cut was observed on the tire. The cut was all the way through the tire, so we put a boot in the tire and will see if that solves the problem over the next few days.

BTW, my wheels are not tubeless capable so i will order a new tire soon just in case to be on the safe side. there are to many positive reports on these tires for me to give up, the ride and handling are great.

Thanks for all the education you have provided, ill keep you posted.

I was beginning to think bob was right.

I don't want to jinx myself here but I believe the problem is solved, 185 miles since the boot and no flats Smiley

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2017 Cruzbike V20
2019 ICE VTX Black
SOLD - 2011 GT Karakorem 1.0 - 2012 Lightning Phantom II - 2004 Lightning P38 2013 Rans Rifle 2014 Catrike 700 - 2014 Bacchetta CA2

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