Re: fast tires

Mark J cleary <mcleary08@comcast.net> wrote:

On 6/12/2025 7:02 PM, cyclintom wrote:

On Thu Jun 12 17:49:01 2025 Mark J cleary  wrote:

On 6/12/2025 4:14 PM, Roger Merriman wrote:

Frank Krygowski <frkrygow@sbcglobal.net> wrote:

On 6/12/2025 2:32 PM, Zen Cycle wrote:

 
It sounds as if you're running the 32s somewhat underinflated. Put
another 10 PSI in and see what you think.

 
Experimenting with tire pressure sounds interesting, and would be a lot
easier than comparing different sizes and brands of tires.
 
But I'm skeptical of anyone's ability to "feel" the probably minor
differences that would result from five or ten psi upward or downward.

 
10 psi is definitely very obvious certainly by gravel bike terms let alone
MTB! I started at 60psi realised it was rather too high 50 psi is
noticeable difference and indeed 45psi that I run now, with the difference
being it?s now tubeless vs tubes, if I?ve had a puncture and had to top up
a tyre I?m well aware that I?m a bit lower than normal and can feel it.
 
Likewise on the MTB 10 psi or even 5psi is quite a difference, if your
running 20/30psi.
 
If your running higher pressure and/or using touring type tyres the
differences will be less. Due to sidewalls and all that.

 
I think the most practical way of detecting a difference would be to use
a road with a consistent, slight downward slope. Coast down it
repeatedly with different air pressure and note speeds. Try for days
with no wind and consistent temperatures if possible.
 
And keep in mind that if the difference is difficult to detect that way,
it probably doesn't matter for most riding.
 
 

Certainly off road it?s a common green gravel folks mistake, aka running
tyre pressures 10 psi over what they need and pinging about the place!
 
Roger Merriman
 
 

 
I actually like a bit more pressure in the tires than some. I hate the
feeling of the tire bottoming out or I go over bump and can feel the
tire give a lot. It makes me uneasy and I always get the feeling I might
be having a flat. When I go in drive way ending ride I have small drive
way bump and that tells me things. If the tires is flexing more than I
like I know it i air time.

 
 
 
 
I am running 69 lbs. in the Gatorskins 32 mm and the bike is WAY too
stiff. There's no way that this is going to bottom out or feel flabby at
those pressures. I will experiment with it but my suspicions is that it
will take 50 to 55 to feel correct. The problem is that it takes a bike
built especially to mount tires that wide. The disc bike with Hunt wheels just makes it.
 
My Time Ulteam looks like it would be too tight vertically to the brake
mount and the front fork.
 
Perhaps they would work on the BMC SCO 01 but I have to sell off a
couple of bikes to get down to the level. At the Moment the Ridley
Helium Di2 is taking priority.
 
Speaking of which - I missed whether Andrew answered me or not - Di2 11
speed levers have space for 3 Di2 cables per lever. It I were to mounf
cables serially would they work or does on lever interfere with the
lines? I would think not since Di2 identifies components with a
component number. If this doesn't work I do have a 4 way interconnect
but that makes the wires longer..

 
How much you weight has most to do with this and the the weight of the
bike. I weigh 170 pounds and my bike about 20.
 

I’m 200 pounds or more don’t really do pounds in uk for human sized weights
generally either stones and pounds or KG.

I run 80 psi in the 28mm tyres on the road bike I used for commuting, ie
I’ll be carrying stuff, so it’s definitely over pressure but deliberately
so to give a margin of error.

For your weight and use 60psi sounds about right as starting pressure but
if you prefer higher pressures then it’s not a deal breaker. After all your
racing so marginal gains etc are much less important!

Roger Merriman