Newbies Tyre Pressure guides

[Zimmerframe]

Hi All,

I know tyre pressures are dependant on many factors. Where you ride, how you ride, tyre type, tyre size, round wheels, square wheels (29 squares just don't seem to fit anything without fouling) bla bla ... but for newbies, and there's probably quite a few who end up here without years of experience and knowledge (like me), it's all mumbo jumbo !

Most tyres state the maximum recommended inflation pressure. But when you're a knowitnot, what's the minimum you could try ?

So, to start, from my experience :

Running DHRII/DHF 27.5+ (2.8) I started with tubes. Initially I was running these at 1 bar (14psi) in the firm belief that lower would give me more grip and comfort - both a requirement for a terrified, rigid, floor staring, incompetent on a hardtail. As I progressed and began to overtake the slower snails, I started to get the odd pinch flat. Which in turn led to constant pinch flats (mainly the rear). I could have just put more pressure in, relaxed and been fine but I didn't..

So I went tubeless. Which is another story and was a nightmare (but only because if my bike shop followed any trade description rules it would be called "Bodger Bikes"). Anyway, that was sorted with the help of a Strava friend I met after I accidentally stole his KOM - Newbies - on Strava, you select E-Bike - not Ride !

With the power of tubeless I started playing with even lower pressures in the search of magic super grip (it doesn't work like that sadly) and an alternative to rear suspension. Down to 0.5 bar (7 Psi). This was a mistake, the tyres are squirmy and all over the place. This does not help confidence or control ! (remember this is just newby basic guide, not pro information). Back upto 0.8 bar (11psi) . Less Squirmy, but frequent rear tyre "Burps" - where the tyre is temporarily dislodged from the rim so it releases a load of air and sealant.

Over the last few weeks I've been coming back up on the pressure. For me, on these tyres, still inept, but improving and can hold my own now with the fast snails. 1.1 bar front and 1.2 bar rear are probably the lowest pressures where I don't get "burps", the ride is still comfortable and I have good control and response with the bike.

So : 27.5+ DHRII / DHF 1.1 / 1.2 Bar (front / rear) - 16/18 psi - recommended newby low risk minimum.

 

[aarfeldt]

My settings are - quite similar:
Front: Bontrager XR4 27.5 x 2.6: 16 psi
Rear: Schwalbe EddieCurrent 27.5 x 2.8: 18 psi

Bike: Focus Jam2 Plus.
Fork: Pike 2019, 1 token, 95 psi
Shock: DeLuxe 2019, 200 psi
Rider weight: 80kg
Shimano E8000, Eco 30/30, trail 80/60, boost 120/70
Trail: XC-trail, very technical, avg speed 22km/h, length 22km.
Setup using Quark and knowledge (for this specific trail)

Did try Boost 300/70 around the trail for the fun of it - 95% useless (too much)

 

[Rusty]

Heh heh heh - the trials and tribulations of tire pressure selection.
No matter what 1-2-3-4 people think there will always be 2-4-6-8 ... Oh, that is a Tom Robinson song too. I digress - I think Newtons Third Law applies ;-)

Me, I am a fat bastard and run higher pressures. I also ran them when I was not so fat and for a very good reason. When I was a teen I did thousands of laps around MX tracks doing tire testing and the thing that was drummed into me by the technicians is that they put a recommended pressure or range on a tire on purpose. You can go marginally above or below that but the further you go the less effective the tire is.
Without getting too technical the recommended pressure is based on the lay-up of the ply, the sidewall composition, the rubber composition and the tread pattern. For a particular tire run at the recommended pressue it gets the best blend of knob bite or grip and rolling resistance. Have seen many magazine articles over the years about running a certain tire at X or Y pressure and laughed. Back when I started riding MTB we actually were able to put a bike onto a dyno and disprove the claims of better rolling resistance - based on actual data.

Anyhoo - I run 25-35psi depending on the tire and the conditions. Running a few CX races way back I found higher pressures actually allowed the tire to cut through the mud and get some grip on the firmer base. Not applicable to MTB unless you are riding in bog country.
If I go below 25 I get so much sidewall flex I have rolled a tire off the rim.

 

[steve_sordy]

This was a revelatory moment for me, finding this on PinkBike's Tech Tuesday series.

Tech Tuesday - Find Your Tire Pressure Sweet Spot - Pinkbike

Read the words, watch the video.

 

[Lee Dove]

I always start at 20/20 psi on a new bike. On my Decoy I am now running 18 front but stuck with 20 rear as any lower I get rim hits (loud clang) and have dented the rim at 18psi.

I run tubeless.

 

[steve_sordy]

Before anyone can take advice on tyre pressures, we'd need to know how much they weigh in their riding gear, what tyres, tubeless or not, and riding style. And then they'd have to try it and see how they like it.

Therefore one approach would be to put pretty much any pressure in and then go from there. But to do that you'd have to know what you are looking for. I started on my first mtb with 60psi (YIKES!). Yes, 60psi, nobody told me any different, not even the bike shop. For ages I wondered why I was being shook to bits if I tried to go as quickly as everyone else. I thought it was lack of skill, not a good enough bike, badly set up suspension, lack of fitness, and so forth. I asked other riders how they managed to be so fast and they told me all sorts of stuff. But not one of them ever mentioned tyre pressures.

And then I found the video on Pink Bike (see post #4 above)

 

[raine]

Before anyone can take advice on tyre pressures, we'd need to know how much they weigh in their riding gear, what tyres, tubeless or not, and riding style. And then they'd have to try it and see how they like it.

This.

Tire pressure is really an individual setting, there is no "perfect" tire pressure that applies to everyone. The factors are too many:

1. Rider weight
2. Riding style*
3. BIke weight
4. Tire size
5. Tire casing
6. Wheel width
7. Terrain
8. Trail features
9. Ambient temperature
10. Elevation
11. Ultimate performance vs. Durability*
etc.

The two with the * will always be different for each person. A person who's "Riding Style" is slower and safer can run a softer setup compared to a rider who pushes the limit and smashes through rough trails and jumps. Likewise, there is that balance between gaining ultimate performance at the expense of tire durability... for example - if you're not racing, it's probably better to add a couple more psi to ensure your tires last the whole day than to go low for maximum grip but expose yourself to pinch flats, sidewall squirm.flex, or at worst you could roll the bead right off the rim.

That said, I generally start around 23/23-psi, then slowly adjust lower until i feel comfortable. When I feel comfortable (not ultimate performance, just comfortable) I take note and make that my "base". From there I adjust depending on where I'm riding. I do find that tire casing alone makes a huge difference in what the "Ideal" tire pressure is... for example, I can run my DH casing Der Kaisers at about 20-psi and have the same support (good grip, no tire squirm) as my Trail Kings at 23-psi, and when I ran Magic Mary's those were in between at around 22-psi for the same feel.

 

[steve_sordy]

"Feel" That's the word I was looking for!

While the bike was in the garage, I set up the tyre pressures using my Topeak D2 digital pressure gauge. Once I was out on the trail the tyres felt a bit harder than usual. I checked the pressures with the D2 and they were each 1psi higher than I had set. It was a very hot day. I let out some air until I had got back to the pressures I liked and hey presto! the ride feel was restored.

Now I know that sounds a bit like the Princess and the Pea fable! I suppose that I could have persuaded myself that letting out 1psi restored the feel, because I'd got off the bike to take action. But I thought something was wrong and stopped to check, no kidding myself there. This is why I use a digital gauge. I have found a pressure that works for me. But I always go off the "feel", using the gauge is just a quick way to get close.

 

[raine]

Feel is a key word in bike setup. So many people focus too much on actual numbers as an indication of if their bike is setup correctly, but it's not all about numbers. Ultimately if the rider feels comfortable, confident, and in control of their bike then IMO that is the right setup for them.

 

[Gary]

As above. Ignore numbers. Especially if you're a noob.
If you can't set your tyre pressures to taste (ballpark) without a tyre guage there's something far wrong IMO.
and the only way to find what you actually do prefer is to ride different pressures and trial and error.

like everything in cycling it has a term. The term is "bracketing".

Your optimum tyre pressures are going to change depending on conditions anyway... and then you'll probably change tyres too.

 

[06z]

Anyone run Cushcore?

 

[miPbiP]

by feel.

on my 29er, like an orange not like an apple. (a slightly soft orange).

on my b+ hardtail, softer.

bump up a kerb, you want to feel the tyre give a little but not ping you back.

you can probably go softer than you think, you want the tyre to conform to trail crap not stutter bump off it.

 

[Dirtnvert]

This thread should come to a speedy decisive conclusion..........