Suitable tyre pressure for MTB race?

Duncan Smith said:

Excuse my naivety here, but it's been many years since I was last on a
mountain bike, and I have my first MTB race tomorrow (Friday Night
Summer Series near Sibbertoft). The terrain covers grass, mud and
gravel. Anyone care to suggest a ball-park figure for PSI as I
haven't got a clue.

Many thanks,

Duncan.

what type of tires? type of race, are you a feather weight or heavy
wieght? etc these all effect. i don't race so...

if you have fairly standurd 2inch or so wide, then 40/50 psi or so, it's
been fairly wet so i'd be tempted to go 40 ish though high enought to
ward off snake bites.

roger

Duncan Smith <[email hidden]> typed:

Quoted message said:

Excuse my naivety here, but it's been many years since I was last on a
mountain bike, and I have my first MTB race tomorrow (Friday Night
Summer Series near Sibbertoft). The terrain covers grass, mud and
gravel. Anyone care to suggest a ball-park figure for PSI as I
haven't got a clue.

As RM says, 40 / 50 is a reasonable start point for almost any terrain, but
adjust it in about 5+ psi increments or you may not feel the differences.

IME, if it's a track that's wll used, then you might need to go up a bit
'cos the trails might be more compacted and bumpy ... however, the converse
can also be true if it's been raining and 'normal' mud-holes become
quagmires where you might fare better with a bit less pressure.

Grass, mud and gravel suggests a lower figure so 40 would be a good start
point, IMHO.

Suck it and see, basically ... 😉

--
Paul - [censored]

in message <[email hidden]>, Duncan

Smith (') said:

Excuse my naivety here, but it's been many years since I was last on a
mountain bike, and I have my first MTB race tomorrow (Friday Night
Summer Series near Sibbertoft). The terrain covers grass, mud and
gravel. Anyone care to suggest a ball-park figure for PSI as I
haven't got a clue.

Ballpark, 35-40 psi. Don't go softer unless you're using tubeless tyres,
otherwise you risk pinch flats. If the surface is mainly hard packed, then
go harder, but given you're on mud and grass I'd guess you need as much
grip as you can get.

With tubeless tyres some of the serious racers will go below 30psi on
really slippery going, but the softer the tyre the more work you'll do,
and in a race that matters. If you go much harder than 40 you'll really
struggle for grip in greasy corners.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
Das Internet is nicht fuer gefingerclicken und giffengrabben... Ist
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watchen das cursorblinken. -- quoted from the jargon file

Duncan Smith said:

Excuse my naivety here, but it's been many years since I was last on a
mountain bike, and I have my first MTB race tomorrow (Friday Night
Summer Series near Sibbertoft). The terrain covers grass, mud and
gravel. Anyone care to suggest a ball-park figure for PSI as I
haven't got a clue.

It depends quite a bit on conditions on the day, and exactly what the
surfaces and gradients are like. Also on the suspension on your
bike. I find that I tend to go faster with my tyres pumped a little
harder than most people recommend for general off-road riding; but on
some surfaces it helps to let a little air out.

In article <[email hidden]>,
Duncan Smith
[email hidden] says...

Quoted message said:

Excuse my naivety here, but it's been many years since I was last on a
mountain bike, and I have my first MTB race tomorrow (Friday Night
Summer Series near Sibbertoft). The terrain covers grass, mud and
gravel. Anyone care to suggest a ball-park figure for PSI as I
haven't got a clue.

High pressure rolls better, gives better protection to the rim and
probably reduces the chance of punctures. Low pressure gives better
grip on soft/slippery surfaces and reduces high-frequency vibration
which might tire your hands/arms/shoulders. Wider tyres can get away
with less pressure, heavier riders need more pressure. You really need
to ride the course to check conditions. If in doubt use your fattest
knobbliest tyres near the recommended maximum pressure - that way at
least you should finish although you might not be fast or comfortable.