I don't need this pressure on

Discussion in 'UK and Europe' started by Doctor J. Frink, Jun 22, 2004.

  1. Hullo,

    In an attempt to get the gf's MTB to keep up with my hybrid I've been
    pumping up tyres to higher pressures to make sure the rolling resistance
    is at minimum. I've put her rears up to 65psi (max stated on the rim)
    and 60psi at the front. With the fat tyres and suspension forks she
    hasn't noticed anything untoward.

    I've also ramped up my hybrid 700c tyres a bit as well to 80psi rear (85
    max rated) and 70psi front. It's definitely a 'bouncier' ride, but only
    really noticable when on rougher ground (stony, pot-holy tracks to
    birding sites).

    What's the line on tyre pressures? Am I too high, too low or is it
    personal preference above a certain minimum? How much should they come
    down (%age) when going 'off road'? From reading around it seems higher
    is generally faster but I've had a hard time finding any figures.

    Cheers,
    Frink


    --
    Doctor J. Frink : 'Rampant Ribald Ringtail'
    See his mind here : http://www.cmp.liv.ac.uk/frink/
    Annoy his mind here : pjf at cmp dot liv dot ack dot ook
    "No sir, I didn't like it!" - Mr Horse
     
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  2. Doki

    Doki Guest

    Doctor J. Frink wrote:
    > Hullo,
    >
    > In an attempt to get the gf's MTB to keep up with my hybrid I've been
    > pumping up tyres to higher pressures to make sure the rolling
    > resistance is at minimum. I've put her rears up to 65psi (max stated
    > on the rim) and 60psi at the front. With the fat tyres and suspension
    > forks she hasn't noticed anything untoward.
    >
    > I've also ramped up my hybrid 700c tyres a bit as well to 80psi rear
    > (85 max rated) and 70psi front. It's definitely a 'bouncier' ride,
    > but only really noticable when on rougher ground (stony, pot-holy
    > tracks to birding sites).
    >
    > What's the line on tyre pressures? Am I too high, too low or is it
    > personal preference above a certain minimum? How much should they come
    > down (%age) when going 'off road'? From reading around it seems higher
    > is generally faster but I've had a hard time finding any figures.


    Swap the MTB tyres to slicks or semi slicks if you haven't already. Makes
    much more difference than trying to run knobblies at silly pressures.
     
  3. On Tue, 22 Jun 2004 21:37:10 +0100, Doki <[email protected]> wrote:
    >
    >Doctor J. Frink wrote:
    >> Hullo,
    >>
    >> In an attempt to get the gf's MTB to keep up with my hybrid I've been
    >> pumping up tyres to higher pressures to make sure the rolling
    >> resistance is at minimum. I've put her rears up to 65psi (max stated
    >> on the rim) and 60psi at the front. With the fat tyres and suspension
    >> forks she hasn't noticed anything untoward.

    >
    >Swap the MTB tyres to slicks or semi slicks if you haven't already. Makes
    >much more difference than trying to run knobblies at silly pressures.


    That's Step 2.

    The appeal of higher pressures (amongst other low-cost resistance
    reducing efforts such as eliminating brakes catching on rims,
    lubrication etc) is that it costs nothing but quite literally fresh air
    ;0). Also reduces flats, allegedly.

    Step 3 (or maybe 1b) is to get GF pedalling faster and braking less.
    Easier said than done.

    Frink

    --
    Doctor J. Frink : 'Rampant Ribald Ringtail'
    See his mind here : http://www.cmp.liv.ac.uk/frink/
    Annoy his mind here : pjf at cmp dot liv dot ack dot ook
    "No sir, I didn't like it!" - Mr Horse
     
  4. Simon Brooke

    Simon Brooke Guest

    in message <[email protected]>, Doctor J. Frink
    ('[email protected]') wrote:

    > Hullo,
    >
    > In an attempt to get the gf's MTB to keep up with my hybrid I've been
    > pumping up tyres to higher pressures to make sure the rolling
    > resistance is at minimum. I've put her rears up to 65psi (max stated
    > on the rim) and 60psi at the front. With the fat tyres and suspension
    > forks she hasn't noticed anything untoward.
    >
    > I've also ramped up my hybrid 700c tyres a bit as well to 80psi rear
    > (85 max rated) and 70psi front. It's definitely a 'bouncier' ride, but
    > only really noticable when on rougher ground (stony, pot-holy tracks
    > to birding sites).
    >
    > What's the line on tyre pressures? Am I too high, too low or is it
    > personal preference above a certain minimum? How much should they come
    > down (%age) when going 'off road'? From reading around it seems higher
    > is generally faster but I've had a hard time finding any figures.


    Some mountain biking people run their tyres quite soft - 30psi or even
    less. But I think these are mainly people who are using their bikes for
    quite short blasts around woodland. There's no doubt that softer tyres
    can help with traction on very soft or loose going, but in general the
    harder the tyres the lower the rolling resistance and for off-road
    cross-country stuff I tend to aim for 50-55psi. On my road bike I run
    at 110psi but that's on little skinny tyres.

    --
    [email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

    ;; Want to know what SCO stands for?
    ;; http://ars.userfriendly.org/cartoons/?id=20030605
     
  5. Tony Raven

    Tony Raven Guest

    Doctor J. Frink wrote:
    > Hullo,
    >
    > In an attempt to get the gf's MTB to keep up with my hybrid I've been
    > pumping up tyres to higher pressures to make sure the rolling resistance
    > is at minimum. I've put her rears up to 65psi (max stated on the rim)
    > and 60psi at the front. With the fat tyres and suspension forks she
    > hasn't noticed anything untoward.
    >
    > I've also ramped up my hybrid 700c tyres a bit as well to 80psi rear (85
    > max rated) and 70psi front. It's definitely a 'bouncier' ride, but only
    > really noticable when on rougher ground (stony, pot-holy tracks to
    > birding sites).
    >
    > What's the line on tyre pressures? Am I too high, too low or is it
    > personal preference above a certain minimum? How much should they come
    > down (%age) when going 'off road'? From reading around it seems higher
    > is generally faster but I've had a hard time finding any figures.
    >


    You can pump them up to the max pressure marked on the tyre. But have you
    considered the option of slowing down to cycle with your gf? It can be very
    dispiriting and off-putting to have someone racing away all the time and
    telling you to go faster. Togetherness is riding at the slowest person's
    speed.

    Tony
     
  6. Peter Clinch

    Peter Clinch Guest

    Doctor J. Frink wrote:
    >
    > What's the line on tyre pressures? Am I too high, too low or is it
    > personal preference above a certain minimum?


    I generally run at or near maximum stated as that gives lower rolling
    resistance. This probably bites me a little on technical stuff on the
    MTB, as does keeping the saddle set high, but I'm generally covering
    ground rather than especially fiddly things and I'm so used to high
    pressure tyres that floppy balloons annoy me a lot where they're not useful.

    > How much should they come
    > down (%age) when going 'off road'?


    It'll depend on the sort of off-road. Work it empirically: try not
    letting any out, and see how you get on; should be okay as long as
    you're not Going For It. I've never felt any real need to let down the
    MTB tyres, so haven't. If the 'bent or Brompton goes onto a forest
    track for a while it's a bit silly as with 100 psi the bike tends to
    jump sideways and ping wee stones out of its way a fair bit. Any more
    than a few miles of that and I'd think very hard about letting a bit out.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
  7. Clive George

    Clive George Guest

    "Tony Raven" <[email protected]> wrote in message
    news:[email protected]

    > But have you considered the option of slowing down to cycle with your gf?
    > It can be very dispiriting and off-putting to have someone racing away all
    > the time and telling you to go faster. Togetherness is riding at the

    slowest
    > person's speed.


    And Tony also knows the answer to this - get a tandem!

    cheers,
    clive
     
  8. On Wed, 23 Jun 2004 08:18:50 +0100, Tony Raven <[email protected]> wrote:
    >Doctor J. Frink wrote:
    >> Hullo,
    >>
    >> In an attempt to get the gf's MTB to keep up with my hybrid I've been
    >> pumping up tyres to higher pressures to make sure the rolling resistance
    >> is at minimum. I've put her rears up to 65psi (max stated on the rim)
    >> and 60psi at the front. With the fat tyres and suspension forks she
    >> hasn't noticed anything untoward.

    >
    >You can pump them up to the max pressure marked on the tyre. But have you
    >considered the option of slowing down to cycle with your gf? It can be very
    >dispiriting and off-putting to have someone racing away all the time and
    >telling you to go faster. Togetherness is riding at the slowest person's
    >speed.


    This is exactly what I do. She goes in front, I tail her rear wheel. It
    was mostly the difference in freewheeling downhill; I'm hard on the
    brakes trying not to whizz past.

    Frink

    --
    Doctor J. Frink : 'Rampant Ribald Ringtail'
    See his mind here : http://www.cmp.liv.ac.uk/frink/
    Annoy his mind here : pjf at cmp dot liv dot ack dot ook
    "No sir, I didn't like it!" - Mr Horse
     
  9. Mark South

    Mark South Guest

    "Peter Clinch" <[email protected]> wrote in message
    news:[email protected]
    > Doctor J. Frink wrote:
    > >
    > > What's the line on tyre pressures? Am I too high, too low or is it
    > > personal preference above a certain minimum?

    >
    > I generally run at or near maximum stated as that gives lower rolling
    > resistance. This probably bites me a little on technical stuff on the
    > MTB, as does keeping the saddle set high, but I'm generally covering
    > ground rather than especially fiddly things and I'm so used to high
    > pressure tyres that floppy balloons annoy me a lot where they're not useful.


    I find one of the biggest benefits of full suspension on VTTs is being able to
    run realistic tyre pressures because the tyre is no longer responsible for doing
    the ride cushioning as well as supplying the traction.

    Since going full-sus I am able to run the same kinds of tyres about 10 or 15 psi
    higher for the same comfort and a lot fewer pinch flats but with better
    steering.

    Bike's even more difficult to carry though :-(
    --
    Mark South: World Citizen, Net Denizen
     
  10. Peter Clinch

    Peter Clinch Guest

    Doctor J. Frink wrote:

    > This is exactly what I do. She goes in front, I tail her rear wheel. It
    > was mostly the difference in freewheeling downhill; I'm hard on the
    > brakes trying not to whizz past.


    Slicks should really help here. Not only can you roll quite a bit
    faster but you actually get more effective control (and feel of control
    IME) for cornering and the like because you've got continuous contact
    rather than a succession of distinct knobs. With more control, less
    feeling of a need to brake.

    Mt MTB has big knobblies on which are great on soft stuff but they're a
    total PITA on the road, making riding harder, slower and noisier than
    I'm used to.

    Pete.
    --
    Peter Clinch Medical Physics IT Officer
    Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
    Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
    net [email protected] http://www.dundee.ac.uk/~pjclinch/
     
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