What 700cx25mm for fixed gear, extremely high pressure and Mr. Tuffy? + Road Bike

Discussion in 'Cycling Equipment' started by Destroyer OS., Jul 28, 2006.

  1. Destroyer OS.

    Destroyer OS. New Member

    Joined:
    Jul 28, 2006
    Messages:
    9
    Likes Received:
    0
    I am constructing a commuter... I have decided to go with 25mm instead of 23mm because I am not going for speed all together. I also want something a slight bit more durable.

    I need something very high pressure. I had some 28mm awhile ago on my road bike and at anything less than 120psi I was flat out miserable. I am a large rider and require as much psi as possible. I have found some continentals that go to 120psi. I however thought they made some for 145psi but have been unable to find them again. Would it be just me or does their website constantly change PSI ratings?

    On my road bike right now I am running Vredestein Fortezza 700x23 Road Tire, which go up to 175psi. I was running them at 160psi today but due to being fit for my bike today, some things changed etc... I was not able to really bust out any speed, my knees are not use to this new position, or my feet, or just plain old learning to lean forward at all.

    I got a flat because my plastic type rim tape has two edges on that both at the same time went right through the tube. I need cotton obviously...

    The thing is even at 160psi (according to some metal pump that cost $55 at a local bike shop, I used one of theirs) I still flatten out the tires. I had them pumped up to a point where I did not once with my Topeka frame pump but the tires came off the rim (I think it was because I had 23-25mm tubes instead of 18-20/23 tubes). I plan to eventually get a Topeka PSI reader.

    Anyways I have been considering if I sell my car to buy some nice tubular wheels and tubular tires.... 200psi is hard to argue with. The bad part is if it get a flat I am flat out of luck. I guess I could try cotton rim tape, 170psi, and Mr. Tuffy? Would the Mr. Tuffy make to much pressure inside, would it push the tire off the rim?

    I know some people do suggest larger tires but in my experience they make you slow and for me it beats me up instead of letting me expercise.

    Anyways I am new to the forum, but thanks in advance for comments, or just for reading my huge post.
     
    Tags:


  2. rek

    rek New Member

    Joined:
    Aug 31, 2002
    Messages:
    1,190
    Likes Received:
    0
    Something sounds strange here. How much weight are you loading the bike up with? If you look down and notice the tyres are deflecting at the contact patches, don't worry: that's normal.

    It's important to note that high pressures not only cause stresses on the tyre casing, but the rim wallls as well. After all, they have to withstand the force on them from the tyre beads so that it doesn't blow off the rim, or otherwise crack or fail. You'd be surprised how low these rim ratings can be; e.g. a Mavic Open Pro is only rated for 138psi with 700x23 tyres.

    Slightly overdoing the pressure (as far as rims/tyres go) isn't much of a problem on flat roads. However if you are descending or otherwise using your brakes a lot at higher speeds, the heat from braking can make things very dangerous indeed re: tyre blowoffs and rim failure.

    I'm not sure what pressures they are rated to; but as far as lightweight, durable high quality tyres go I can strongly recommend the Continental Grand Prix 4-Seasons. Low weight and racey rubber compound like a GP3000, puncture and sidewall resistance like a Gatorskin.. Good road feel too; just like a Conti race tyre, and much better than Michelin anything IMO. Not quite as nice as Vittoria Open Corsas, though, which are the benchmark in this regard. They're available in 700x23, 25 and 28. They can also be bought rather cheaply from www.probikekit.com :)

    In my experience Mr Tuffys have very little influence on pressure capacity. I actually managed to stuff a Tuffy strip designed for a 700x32-41 sized tyre, into a 700x25 one, without any ill effects.. it was actually quite easy, and probably gives added sidewall protection compared to the 'proper' size ;)

    If I were you though, and had doubts as to the load capacity of typical skinny road tyres and rims, I'd be going for a more touring-oriented rim and tyre.. after all, that is what they are designed to do.
     
  3. Destroyer OS.

    Destroyer OS. New Member

    Joined:
    Jul 28, 2006
    Messages:
    9
    Likes Received:
    0
    I am going to through in some Mr Tuffy's because I discovered if my pressure is really high (where it feels nice) then puncture flats happen easily. The reason is the tire becomes un-supple so things go right through, it has no give.

    I have old rims, not designed to be light aside from they are not steel. They seem to hold up fine.

    I load my bike down with me... Well I got a bag with a pressure guage (topeak), frame pump, tire irons, and a tube. Then there are three water bottles on my bike.

    At a local bike shop I found some 25mm I had not previously seen I am going to use, they look nice, run 120psi, should work nice.

    Thanks for the reply.
     
  4. Peter Hummers

    Peter Hummers New Member

    Joined:
    May 18, 2006
    Messages:
    18
    Likes Received:
    0
    Actually tubulars are much easier to deal with on the road ... just carry a spare or two. Rip the flat one off the rim and shove the new one on and pump it up (people used to do this _during_races_, l-o-o-ng ago). Maybe carry a tube of cement, too. It's small.

    The wheels aren't actually all that expensive -- they're a simpler design than clincher wheels.

    Then on a weekend in front of the TV or whatever you can patch your flat(s).

    There are some good articles on tires from Jobst Brandt on this page:

    http://www.sheldonbrown.com/brandt/index.html
     
  5. geoffs

    geoffs New Member

    Joined:
    Sep 8, 2003
    Messages:
    558
    Likes Received:
    0
    You need for high pressures doesn't add up.
    We manage fine on the tandem with a rolling weight of 170kg using 700x28c Gatorskins at 110psi. If we use 23c the pressure goes up to 130-140psi. If you are a single person that weighs more than this, trying to run narrow tyres isn't what you should be trying to do.

    The only time high pressures are used is on a perfectly smooth velodrome track and not general commuting.
     
  6. mikesbytes

    mikesbytes New Member

    Joined:
    Apr 12, 2006
    Messages:
    1,717
    Likes Received:
    2
    The pressures you are using are way too high. The tyres are suppose to flex, this makes them roll more efficiencly over the road surface.

    How much do you weigh?

    I use to use Mr Tuffy, but I had problems with them causing flats, where the tyre went up against the end of the Mr Tuffy. I feel that they are suitable upto 100psi and after that I wouldn't personally use them.
     
  7. Destroyer OS.

    Destroyer OS. New Member

    Joined:
    Jul 28, 2006
    Messages:
    9
    Likes Received:
    0
    Well I am a lot less that 170kg; I would venture 138kg or less.

    Could you explain your Mr. Tuffy situation better?

    My rear tire went bad on me.... I managed to break a spoke, replaced it... Then put on a 700cx25mm Mich tire. It is definatly not as fast as my Fortezza by any means. It is harder to pedal... I am not sure I like it for my road bike. For my fixed gear (shortly) I would probably be fine on 25mm; that is my plan.
     
  8. mikesbytes

    mikesbytes New Member

    Joined:
    Apr 12, 2006
    Messages:
    1,717
    Likes Received:
    2
    Where the end of the Mr Tuffy met, they were pinching the tube
     
Loading...
Loading...