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700c X 25 tyres
#1
Hi

I've been using the Peugeot Premiere racer I got given by my neighbour a lot recently, mostly at weekends but I've even been riding it to work, the problem is I have now had two punctures on the bike, always on the back wheel and I think they are always from hitting drain covers or bad repairs in the road.

The front wheel seems like the original wheel but the back one has been replaced with a fairly new one, the rim seems slightly wider and flatter then the front wheel, the tyre is also newer, it's a Nutrax one whereas the front one is a vintage Michelin select.

I was going to replace both tyres and tubes with new, getting some good quality tyres and sticking some slime tubes in for good measure, both tyres on the bike at present are 700 x 25c, but the rear one seems like it could do with being a bit wider, I had a look online and have seen 25c, 28c and 38c, I take it a 28c tyre that replaces a 25c on the same rim will just give a little more roundness to the tyre and will give more in the sidewall, so hopefully the ride wont be as harsh and it should deflect the bumps more.
Cannondale, handmade in USA............................................Refined in Surrey, England
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#2
25, 28, etc refer to the section width and section height - on most bicycle tires they are equal - in millimeters - nominally, there is some variability.

700c is the designation for the rim - and it is a borderline meaningless designation with a long history. The bead seat diameter of a 700c (aka 28", aka 29er) rim is 622mm.

Is there room on each side of the tire? Going from 25-622 to 28-622; you need an extra 1.5mm on each side; AND an extra 3mm clearance on top (brakes, brake support, bottom of the fork, fenders).

Slime - DON'T it. All it is good for is messing up the valve. When you do get a puncture with slime - it gives you, maybe, and extra 100 feet of riding before you are down on the rim.

Puncture protection - get Kevlar belted tires, tire liners and thorn resistant tubes. The thick thorn resistant tube will actually hold quite a bit of pressure after the cause of the puncture is removed - often enough to get a couple miles or more. But if it is a nail that stays in there - the drop fast like any other tube. All of the above add mass and rotating inertia. More rotating inertia makes the bike feel heavy.

I commute 18 mile round trip on the streets of San Jose; which have glass, nails, screws, rough pavement, etc.

Get the largest tires that will fit; and as much protection as you are willing to drag around.
Nigel
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#3
(09-01-2013, 03:59 PM)nfmisso Wrote:  Is there room on each side of the tire? Going from 25-622 to 28-622; you need an extra 1.5mm on each side; AND an extra 3mm clearance on top (brakes, brake support, bottom of the fork, fenders).
Slime - DON'T it. All it is good for is messing up the valve.
Get the largest tires that will fit; and as much protection as you are willing to drag around.
Exactly.
Also, if you're riding little 25mm tires (speedy, nippy, fast) why would you put a quarter pound of green liquid in each of them & defeat a great deal of that?
The rear tire is the one that normally takes the abuse, it also has the most weight on it.
Don't hit drain covers & road repairs, lol! It's a skinny tire bike.
Never ride with the tires (especially the rear) under inflated, that is probably why the drain covers give you trouble.
How much do you weigh?
How much room is there for a bigger tire?
I have friends that swear by Continental Gatorskins & Hardshells.
Perhaps a 25 or 28 in the front & a 28 or 32 in the rear. Note- my cousins Gators actually measure undersized by 1 or 2mm.
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#4
The Conti Grand Prix 4 Season (or somesuch) in 28mm are slightly undersized (I have been told). You might be able to fit them in. They are reasonably fast and offer better puncture protection than the GrandPrix 4000s - and these are already pretty good for a racing tyre. For me, even when still commuting by bike, the GP 4000s were good enough. In those three years I had only three flats. I also run latex inner tubes, they supposedly offer a better puncture protection (more flexible) and decrease rolling resistance, however they loose air quite fast - check pressure before every ride (with butyl tubes you can get away checking pressure weekly, even on a road bike).
You have to keep in mind, that (in general)
- wider tyres can be ridden with lower pressure
- lower pressure gives a smoother ride
- too low pressure increases chance of pinch flats
- lower pressure can be faster (when compared to maxing out the rating of the tyre)
- tyres with better puncture protection are slower
- highest end racing tyres often have poor puncture protection (tradeoff mentioned above)

What type of punctures did you have? Was it "snake bites" (or pinch flats), two punctures close to each other, on on the top(ish) side of the tube, one in the bottom? Those are the results from riting underinflated. The tyre is then pinched between rim and road, puncturing it twice. Other tings to remember: when fixing a flat, try to find the offending object in the tyre. I found long glass shards, metal strands, stone splinters (I guess flint, from sharpness and colouring) in my tyres... sometimes they are not easily found, you replace the tube and a couple of km later the tyre is flat again -> "fakking, änosä flädd tie-ä", as N. Stadler so aptly put it...
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#5
I had (have) a similar issue. The stock front tire (also 700c x 25) on my newish bike went flat in two weeks. The shop recommended some kevlar belted tires as a replacement. Took the plunge and am hoping for good flat protection.

What I did get right off the bat was a tougher to pedal bike and a harsher ride. The minimum pressure on these is 115 lbs.
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#6
(09-04-2013, 02:32 AM)Robert 7 Wrote:  I had (have) a similar issue. The stock front tire (also 700c x 25) on my newish bike went flat in two weeks. The shop recommended some kevlar belted tires as a replacement. Took the plunge and am hoping for good flat protection.

What I did get right off the bat was a tougher to pedal bike and a harsher ride. The minimum pressure on these is 115 lbs.

".....as much protection as you are willing to drag around."
Nigel
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#7
(09-04-2013, 03:13 AM)nfmisso Wrote:  
(09-04-2013, 02:32 AM)Robert 7 Wrote:  I had (have) a similar issue. The stock front tire (also 700c x 25) on my newish bike went flat in two weeks. The shop recommended some kevlar belted tires as a replacement. Took the plunge and am hoping for good flat protection.

What I did get right off the bat was a tougher to pedal bike and a harsher ride. The minimum pressure on these is 115 lbs.

".....as much protection as you are willing to drag around."

Feels like dragging a suit of armor, AND a sheild, LOL.
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#8
I've used Schwalbe Marathon Plus, they are heavy but for puncture protection they are probably the best available. There are lots of options, but I have come to trust them more than any other tire, not that I know ever single tire type out there.
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#9
(09-04-2013, 02:32 AM)Robert 7 Wrote:  What I did get right off the bat was a tougher to pedal bike and a harsher ride. The minimum pressure on these is 115 lbs.
What tires did you have & end up with.
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#10
(09-04-2013, 05:49 PM)1FJEF Wrote:  
(09-04-2013, 02:32 AM)Robert 7 Wrote:  What I did get right off the bat was a tougher to pedal bike and a harsher ride. The minimum pressure on these is 115 lbs.
What tires did you have & end up with.

Started out with Bontrager T1's, changed to Specialized all conditions Armadillo's.
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#11
Armadillos - should have warned you about those. They are tougher than nails and glass - look for bent nails and broken glass after you ride over them. They have to be the heaviest tire out there.

Another WARNING - make sure that they are properly inflated, the MINIMUM means it. They will experience severe tread separation in a very short period. Properly inflated they will last forever.

Each Arrmadillo makes the bike feel 20lbs heavier.

Thorn resistant tubes and STOP FLATS 2 liners with "regular" kevlar belted tires are MUCH lighter.

As far as puncture protection, the Armadillos are tops.
Nigel
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#12
The best way I can think of describing the Armadillos? It's like being in the next higher gear than with regular tires. Some gears that I used before I won't go near now.

They are fast as... well an armadillo.

On the plus side they do look pretty cool, and there is something to be said for puncture resistance. Whether or not I can stand them in the long term is an open question.

Thanks for the heads up on pressures. Will keep an eye on it!

Apologies to Surreypete for blabbing it up on his thread!
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#13
(09-04-2013, 11:55 PM)Robert 7 Wrote:  ....They are fast as... well an armadillo......

the roll really fast downhill.....like an armadillo curled into a ball...
Nigel
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#14
(09-05-2013, 02:15 AM)nfmisso Wrote:  
(09-04-2013, 11:55 PM)Robert 7 Wrote:  ....They are fast as... well an armadillo......
the roll really fast downhill.....like an armadillo curled into a ball...
Ha Ha, I get it, like the critter rolling down a hill.
Interesting, I have heard that the conti gators were a bit more harsh, but have not heard speed complaints. I know prolific riders who've worn thru multiple sets. The folding bead ultra hardshell is 2oz lighter than your original Bontrager, perhaps try one next time. Sorry the Armadillo is slow for you.
Is surreypete 1 & done?
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#15
Looking into it, the original tires were 360 grams, the Dillos 435. Doesn't sound like much? Anyway have decided to give them a good long term go. If they are as good as advertised durability wise it should be well worth it. They are one heck of a workout if nothing else.

You can beat them up, but they'll fight you back. There's a certain balance there. (LOL @ the rolling downhill post)
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#16
General note - the reason belted tires are slower than unbelted is not primarily due to higher weight. Rather, all the belting and extra protection in the tire casing makes it stiffer and harder to bend. Since the tire is constantly being bent and unbent as you ride, the stiffer casing soaks up a lot of your energy ("rolling resistance"). I think Armadillos are particularly bad because they have extra durable sidewalls. The sidewalls of a tire flex a lot at the contact patch as your tire rolls.

There's pretty good evidence that many high end tires with very high thread count and supple casings are better at avoiding flats than cheaper, unbelted tires. But sadly, nothing prevents punctures as well as a stiff, thick belt between you and the road.
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#17
That is why I like Schwalbe Marathon Pluss, the rubber layer in the tire works very well. I've not had a flat in years with those tires ( I have with others though) It is the type of rubber inner layer I think, which allows the tire to flex the right way and give low resistance. I've heard some absolutely hate them, but I don't mind the downsides of heavy tires too much. It's a couple of years since I tried other flatless tires, but they are so far the best I have tried.
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#18
A thing I have noticed as a new Armadillo rider. With them properly inflated (the sidewall says between 115-125 lbs, I put 'em right in the middle at 120) they have an entertaining affect as you ride. Roll over a largish pebble at just the right angle (not on purpose!!) and that sucker will POING! Shoot out from the side! Maybe I'm easily entertained but this morning on the way to work it happened with a dime size pebble- felt it on the handlebars when it shot out- and I swear it flew twenty feet. Grinned all the way into work.
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#19
(09-05-2013, 02:45 PM)DaveM Wrote:  General note - the reason belted tires are slower than unbelted is not primarily due to higher weight. Rather, all the belting and extra protection in the tire casing makes it stiffer and harder to bend. Since the tire is constantly being bent and unbent as you ride, the stiffer casing soaks up a lot of your energy ("rolling resistance"). I think Armadillos are particularly bad because they have extra durable sidewalls. The sidewalls of a tire flex a lot at the contact patch as your tire rolls.

There's pretty good evidence that many high end tires with very high thread count and supple casings are better at avoiding flats than cheaper, unbelted tires. But sadly, nothing prevents punctures as well as a stiff, thick belt between you and the road.

Informative post. I'm thinking the point is that a super stiff tire like the Armadillo is similar to a solid tire as far as rolling characteristics?
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#20
(09-06-2013, 11:10 PM)Robert 7 Wrote:  I'm thinking the point is that a super stiff tire like the Armadillo is similar to a solid tire as far as rolling characteristics?

They're really not like a solid tire. Definitely a bit slower than a nice, light, high end tire. But solid tires ride horrible and are extremely heavy. (Also a nightmare to install)
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