[Closed] Tyre Pressures

wow, 40psi sounds like tons. I've got around 18psi in my rear and 15 up front.

min pressure that i can go down to without getting pinch flats.

depends where and how you ride. I imagine you could probably get away with about 5psi on the pavement...

add more for rocky areas, add more again for riding like sack of spuds.

Way lower.

Try 27-30psi and feel the grip.

PaulD

Very helpfull thanks.

Lets assume im not riding on top of snooker tables.

Can people really tell the difference between 3-4 psi?

Pump it up till it's hard then deflate till you can poke the centre a bit with your finger. Job done!

Too many factors, one can only find out by trial and error:

How fast you go and if you tend to hop trail hits
Frequency of trail hits
Tyre/rim volume
Bead/rim snugness
Rear suspension settings

If you aren't on tarmac, you want to go quite low to slow the rebound which majorly improves speed and tracking/grip.

40PSI should be fine as it is rock hard. If you don't mind me asking, are you heavy I supopse if you were nearing 100kg you might have problems? Or, more likely is your pump actually reading the pressure accurately?

Far too many variables involved, really is a case of trial and error, from experience I am finding NN's very pressure sensitive and as asked above, 3-4psi really does make a difference between them gripping and pinging off everything.

Just to clarify im 90kgs and i am just trying to work out just how low i can go with the pressures.

buzz your right its probably going to be trial and error , keep dropping pressure towards 30 psi until i get my first pinch flat.

I ride mine at 40psi and managed to get 2 pinch punctures at coed y brenin, wouldn't want to go much over 40 though! i think it's a safe bet

What is everyone else running not tubless btw.

How about a rider weight tyre make tyre width and tyre pressure list?

Of course, this thread assumes everyones pressure gauge's are all calibrated.

Ive had two and they were about 10psi different.

Short of everyone using the same gauge i guess thats what we have to do.

as asked above, 3-4psi really does make a difference between them gripping and pinging off everything.

I don't think my track pump, or my eyes are capable of gauging such a small difference!

Squeeze the tyre - want it more like an orange than an apple

I found out a long time ago that 45-50psi worked for me and my riding style, any less and the pinch flats start.

Squeeze the tyre - want it more like an orange than an apple

I've eaten my apple for today. Will a tin of pineapple chunks suffice for comparison?

At last Dibbs thanks.

35 ish psi for me - any lessand the tyres squirm around in a horrid manner. Dunno how someone can cope with under 20 psi - that just feels awful to me

Hi Drook, that's an interesting alternative. Please feel free to experiment 😯

Apple v. Orange was their polite way of suggesting we'd all overinflated our tyres, and that perhaps a few psi here or there isn't actually the issue.....

I'm 85KG and have around 35psi. Although, I run tubeless now.

Never really gone up to 40psi with tubes though.

you need one of these:

http://singletrackmag.com/forum/topic/adaptrac-system

Some saying they run 18 and 15 psi is just crazy. My wheels would look in some state after about 5 mins.

i weigh just a shade over 90kg and run about 40 psi in my 29er tyres on my paradox.
if i run much less, i get pinch flats when drops or jumps go wrong.

works for me.

I always run a minimum of 50psi in mine the harder the better.
i certainly do not understand these low pressures at all 🙄

I guess running wide rims and high volume 2.4 tyres, oh, and yes, tubeless 😳 means I can get away with sub 20psi. Sorry to confuse, but even my tubes bike max 25psi.

peanut - do they not squirm / roll around under cornering?

They really don't, they just feel as if they are molding more to the ground, more grippy and less like they are just 'skimming' over the surface as I find with higher pressures. More confidence inspiring in my experience.

fairhurst - Member

I always run a minimum of 50psi in mine the harder the better.
i certainly do not understand these low pressures at all

i despair..

I too am about 90kg and run 29er rims with NNs
I find 40psi way too much, about 25-30 seems to work for me.

the harder the better for my riding style pinhead

Is it common to ignore rec pressure ranges marked on tyres? My Bontragers tyres say 40-65 and I have them towards the bottom end. But I am always surprised to read mag articles and threads here talking about running much lower ps1.

Lower pressures do run more risk of blowing off the rim. I reckon that's why manufacturers don't recommend them.

I'm about 90kg with gear. XC hardtail has Small Block 8s Front:20-30psi Rear:25-35psi (depending on conditions\trail). I've found it's a nice compromise with low profile tread and low pressure. It rolls fast, grips and conforms well and is forgiving on rougher sections.

AM bike has Nevagals with similar pressure. I've found some nobblys roll better on hard surfaces at lower pressure too, I think it's because the nobbles recess back a bit giving a flatter contact area.

To be honest it's all down to preference, do some experimenting and go with whats feels right for you.

TandemJeremy - Member

peanut - do they not squirm / roll around under cornering?
Posted 1 hour ago # Report-Post
peanut - Member

They really don't, they just feel as if they are molding more to the ground, more grippy and less like they are just 'skimming' over the surface as I find with higher pressures. More confidence inspiring in my experience.
Posted 1 hour ago # Report-Post

I started last year with tyres at 60psi, have been slowly reducing it to 40psi now.

Just starting to get wary about reducing it much more than 40psi. Might try 40R 35F tomorrow and see what happens.

Blimey, I'm a fat knacker (92kg) and with tubes I used to run 35psi. Now with tubeless I run 25-28 no probs at all.

When I first started biking I used 60psi... Now I'm at about 30-40 psi f+r depends on when I stop pumping, hadn't thought about using different pressure f+r, I'm 74kgs riding a prince Albert. I found 60psi too hard but didn't get pinch flats, I find if I go lower the tyre squirms way too much, oh and tyres are RR on back NN on front with tubes.

i was thinking of increasing mine up to 65psi

fairhurst, you're just phishing now.

For tubeless, see the formula here:

http://www.notubes.com/RecommendedTires.aspx

In British that's weight in stone doubled, -1 for front, +2 for rear. A very sensible starting point for a rider that's neither fast nor slow, smooth nor heavy. I'd go higher for tubes but not a lot. Obviously if they pinch/squirm go higher. 65psi is just silly.

When I run Conti 1.5s I use 60-65psi but even then it has to be pretty smooth, I'd struggle where I normally ride even at those pressures.
I use 90psi on the CX, I had a pinch flat last year when I let the pressure drop as low as 70.

Wow a lot of high pressure salesmen here!

On 2.4 Conti MKs with tubes, 88kg rider, hardtail, I am running from 22 to 26 PSI front and rear for off road. I love the grip and comfort. I'm not fast on the downs, and don't hit rock gardens or big jumps / drops, so YMMV.

I run 40 PSI on road for my Schwalbe Supermotos... nice!

My XC bike with 26x2's is running at 50psi front and rear.

My road bike with 700x23's is at 100psi front and rear.

I run high pressures to keep the rolling resistance low.

I run high pressures to keep the rolling resistance low.

That only works on road with smooth tyres.

Off road, it is less efficient to have the tyre and bike bumping about over every stone, more efficient to absorb the bumps at the tyre. Also with knobbly tyres, high pressure causes more rolling resistance as tyre ratchets from knob to knob rather than rolling smoothly.

I'm always a bit amused by people who seem to think that they're inflating tyres to exactly 28psi or whatever. There's no way the gauges on most pumps are that precise, or repeatable. And if you pump the tyres up in a cold garage and then ride on a hot day you'll end up with 29psi anyway 🙂

Just to throw the cat amongst the pigeons, how many of you actually know how accurate your gauge is?

I have 4 track pumps and several mini-pumps with gauges.

When I tried to calibrate against a standard (car tyre and 2 garage gauges), I was horrified to see my pumps were just random.

For a real 32psi, I had my pumps showing 22 to 40 psi.

I learned that what I thought was 35 was actually under 20, so no wonder I had a few pinch-flats.

I have calibrated and written what to use on the pumps....not simple but essential. I used a dual-headed pump to calibrate against the car tyre, then a large MTB tyre with a presta, then the other presta-only pumps.

PaulD

Probably depends on lots of things like tyre choice, rim width, riding style etc but i'm a similar weight to OP and generally run between 30-40 F+R (on 2.3" single ply tyres) for dh/trail use. Closer to 30 when the going is rough. Nearer 40 if relatively smooth. I still get the occasional pinch flat but I don't like how my bikes handle if the tyres are too soft or hard. My jump bike tyres are rock hard though (70-80psi) but that's a conscious decision to sacrifice comfort for speed.

I'd say try 35 and see how you get on (bring a spare tube though :D)

I run high pressures to keep the rolling resistance low.

lower pressure = less rolling resistance ...

... apparently:

I just don't know ow some of yo can run such low pressures even with tyres with stiff sidewalls - I just hate the squirming and loss of accuracy as the tyre rolls in corners.

GeForce - thats an interesting bit of data but its by no means conclusive - low speed only and not all conditions.

35ish for me (better expressed as the oranges and apples analogy above).

Maybe I'm too much of a geek, but I use a Topeak digital tyre gauge. Also, the original post was regarding 29er tyres, which being larger volume would run at lower pressures anyway.

Nobeerinthefridge - Member

fairhurst, you're just phishing now.

they seem to be running slightly flat at 50psi so was only thinking of increasing the pressure

the only thing you can deduce from those charts is riding through grass is a bitch and i didn't need a graph to tell me that ! 🙂

Checked my pump with a digi pressure gauge, its within 1 psi.

Tried 35 front 38 rear today, all ok.

Will go for 35 front and rear next time.

I think the report is fairly conclusive, bar [joke] needing to include a couple more terrain types for completeness, as TJ suggests.

The report is all about the uphill though, not really covering the benefits/risks of lower pressures downhill (or the trade-off) which is as important to the overall choice of pressures.

I think the "gauge accuracy" argument is a strawman; unless different pumps/gauges are used every time alternative pressures are tried, which I'd be surprised by.

I think the effectsof pressure will also be iddiffernt at higher speeds.

As for pressures - different tyre work at different pressures for sure - some contis need a fairly high pressure to stop the knobs collapsing - better grip at 40 psi than 30 - mountain kings for example - rubber queens I can run softer than mountain kings

6psi Front and 7psi rear.

Yes, it's a fat bike...

Some bloke with most of his arm missing when his tyre peeled off the rim advised me not to run them lower than 25psi. I'm going with that.