Tyre pressure

a148pro

Am I alone in always riding tires at max pressure?

I find they're much faster and I almost never get punctures, which is massive for me as I hate the hassle of a flat

I get that the ride is slightly bumpier, but i've never noticed any discomfort as a result. I've never come back from a cycle thinking my hands are shot. I have turned back from a cycle when I was slogging up hills feeling I was sinking into the ground

The only drawback I notice is off road on gravel bike, tires slip on mud or going up steep hills. But it's not enough to make me care as I don't ride that stuff often and would hate to have to deal with a flat off road in the yet more

Riding specialized turbo cotton 26s at 110 on the road bike. These were sold to me as a racing tyre with no puncture protection that would only last a few months. They are well into their second season and haven't gotten a single puncture.

gravel bike is on 37s at 75, tubes

I weigh about 83kg

Am I mad?

Wishbone Ash

Wouldn't they be a bit sketchy in the wet at max pressure?

magicbastarder

a148pro wrote: »

I find they're much faster

have you actually tracked your speed at different pressures?

from what i've read, one theory goes along the lines of:
a) going fast on a bike = more road buzz. it's a simple fact that you'll get more high frequency vibrations through the bars if you're hitting the bumps harder and faster.
b) riding with tyres pumped to max pressure = more road buzz. it's obvious, you'll have less dampening of road variations with high pressure tyres.

the mistake would be to assume that if you're trained to associate road buzz with speed, you're also interpreting road buzz from high pressure tyres, as speed. i.e. it *feels* as if you're going faster, but you're not actually.

i weigh about 75-78KG (i hope! have not weighed myself since christmas, probably), and i run 25mm tyres at 80PSI.

a148pro

Wishbone Ash wrote: »

Wouldn't they be a bit sketchy in the wet at max pressure?

It is - I should have added that I almost never cycle in the wet and take it handy on descents (basically, I'm a wuss, everything about this thread confirms it)

magicbastarder wrote: »

have you actually tracked your speed at different pressures?

the mistake would be to assume that if you're trained to associate road buzz with speed, you're also interpreting road buzz from high pressure tyres, as speed. i.e. it *feels* as if you're going faster, but you're not actually.

interesting - so my mind is treating the increased road buzz as going fast when I actually am not? I don't have a power meter so any measuring would be subjective. It definitely feels faster but maybe that's your point.

Maybe the answer here is what they run in professional cycling, one assumes that is scientifically based. I know there's a theory that on non smooth surfaces firm tires will slow you down on little bumps, which makes sense.

new2tri19

I used to run 120 pressure all the time until one Sunday I was out doing a few laps at a set power and got a flat. Changed out tube but only hand pumped to 70-80 by guage on pump and continued my reps. I felt slower but I was doing 20 minute repeats at a set power so my aim was to hit the wattage. Suprised later when I looked that the later reps where faster for same power.
I run them around 100 now more out of fear that a lower pressure will cause punctures.

a148pro

Wow, that's more or less exactly the info I was looking for, thanks

Large bottle small glass

a148pro wrote: »

Wow, that's more or less exactly the info I was looking for, thanks

We are very close in weight, I run 28mm road tyres at 65 front 70 ish rear. On 2 occasions in last year on slimy surfaces I've dropped pressure to 40 or so without issue.

I only ride on poor quality roads and my only pinch flat in last 5 years was on a forest track about 2 months.

Pick your line, avoid potholes and pinch flats are rare.

I run tubeless cx 35mm at about 40 ish

75psi off road, especially at front is going to give you very poor grip.

I find the road bike rough for the first few km after getting used to cx bike

kenmm

I still go with the "Thin tyre, max pressure" - but i know at this stage its some sort of psychosomatic/ mental issue I have as the science seems to say otherwise.

After COVID I lost a bit of fitness, back on it now, but i notice that with full pressure an crappy roads and me being a bit unfit, I am getting fierce headaches after 50 odd KM (Swollen head, rattling around on bumps).

If my new bike ever arrives, I plan on experimenting with this a little bit. Maybe going tubeless as apparently that helps the punctures?

new2tri19

It's one of them things its counterintuitive when I am pumping my tyres I try remember not to go to max pressure. I would say if you where in a velodrome or something on perfect surface 120 would be faster than 70-80 but for most irish roads there is no real advantage and maybe a disadvantage in higher pressure as tiny surface bumping is a power loss or something. I don't know the science! But instinctively you would think higher pressure is faster.

smacl

Large bottle small glass wrote: »

We are very close in weight, I run 28mm road tyres at 65 front 70 ish rear. On 2 occasions in last year on slimy surfaces I've dropped pressure to 40 or so without issue.

I only ride on poor quality roads and my only pinch flat in last 5 years was on a forest track about 2 months.

Pick your line, avoid potholes and pinch flats are rare.

I run tubeless cx 35mm at about 40 ish

75psi off road, especially at front is going to give you very poor grip.

I find the road bike rough for the first few km after getting used to cx bike

84kg myself and use the CX bike almost exclusively these days with the road bike attached to the turbo for the Winter. Currently on 38c Schwalbe G-One all-round gravel tyres also at ~40 and wouldn't want any higher on gravel. For me I reckon the 38c gravel tyres are ~5%-10% slower than the 32c slicks on previously but worth it for the versatility.

magicbastarder

kenmm wrote: »

After COVID I lost a bit of fitness, back on it now, but i notice that with full pressure an crappy roads and me being a bit unfit, I am getting fierce headaches after 50 odd KM (Swollen head, rattling around on bumps).

you mean after lockdown, or you actually got the pox?

kenmm

magicbastarder wrote: »

you mean after lockdown, or you actually got the pox?

ha - no I mean after adding a few kgs and losing a bit of cardio over lockdown.

I tend to find I overheat a little and get headaches when running boneshaker pressure over some of the roads we have!

magicbastarder

aha, i thought the headaches might have been a lingering symptom.

smacl

kenmm wrote: »

ha - no I mean after adding a few kgs and losing a bit of cardio over lockdown.

I tend to find I overheat a little and get headaches when running boneshaker pressure over some of the roads we have!

I'd guess that if you're being rattled around because of high tyre pressures, whatever about speed you're going to expend a lot more energy than if you're having a smooth ride. I found I used to be slightly out of the saddle much more often on the road bike with narrow tyres on crap roads, purely to smooth out the road buzz.

kenmm

smacl wrote: »

I'd guess that if you're being rattled around because of high tyre pressures, whatever about speed you're going to expend a lot more energy than if you're having a smooth ride. I found I used to be slightly out of the saddle much more often on the road bike with narrow tyres on crap roads, purely to smooth out the road buzz.

ye - I do adjust position, come out the saddle a bit (but probably need to be more mindful)- but I think the heat and hitting some larger ones give me a jolt.

Maybe its a touch of general bike handling - core strength dropped a bit too so being lazy and just sitting there more than normal

Once I get the fitness back a bit and we hit autumn it will be grand (although, I am not completely unfit maybe I need to get checked out!)

smacl

kenmm wrote: »

ye - I do adjust position, come out the saddle a bit (but probably need to be more mindful)- but I think the heat and hitting some larger ones give me a jolt.

Maybe its a touch of general bike handling - core strength dropped a bit too so being lazy and just sitting there more than normal

Once I get the fitness back a bit and we hit autumn it will be grand (although, I am not completely unfit maybe I need to get checked out!)

Wider tyre at lower pressure could make your cycling way more enjoyable. I'm finding with the bike set up for comfort first I'm getting out a lot more, losing a bit of weight and still hitting PRs on most rides. That said, I'm nearly always riding solo so not under any pressure to keep up with a group and my average speeds would be lower than most here.

Effects

smacl wrote: »

Currently on 38c Schwalbe G-One all-round gravel tyres also at ~40 and wouldn't want any higher on gravel.

I have those tyres on a gravel bike and find I get a good few punctures with them when cycling off road. I keep them fairly well inflated too.

Duckjob

I used to pump the 25mm tyres on my road bike to the 120psi max assuming it would be quickest.

I found on the knobbly roads where I live the ride felt very rough, so I changed tack and started pumping to 100psi instead.

As expected, the ride was smoother but I was surprised to find that I was able to keep the same pace with less effort. I guess before I had been losing energy through being minutely airborne a lot of the time

a148pro

Going to have to try it at lower pressure so, thanks for the tips

Officer Giggles

I have always been a pump tyre to max pressure cyclist, is there any way of working out the ideal pressure taking into account the tyre width and rider weight

kenmm

Duckjob wrote: »

I used to pump the 25mm tyres on my road bike to the 120psi max assuming it would be quickest.

I found on the knobbly roads where I live the ride felt very rough, so I changed tack and started pumping to 100psi instead.

As expected, the ride was smoother but I was surprised to find that I was able to keep the same pace with less effort. I guess before I had been losing energy through being minutely airborne a lot of the time

So was new wheels time and put new tyres as well.. went for 25mm and a smidgen under 100psi, quite enjoyable and no noticeable loss of performance. Might up it slightly to just over 100 but so far so good!

kenmm

Officer Giggles wrote: »

I have always been a pump tyre to max pressure cyclist, is there any way of working out the ideal pressure taking into account the tyre width and rider weight

I'm sure I've seen online calculators for this that give a rough rule if thumb, but don't know how accurate they are.

G1032

Officer Giggles wrote: »

I have always been a pump tyre to max pressure cyclist, is there any way of working out the ideal pressure taking into account the tyre width and rider weight

https://play.google.com/store/apps/details?id=com.mavic.mymavic

Mavic have an app that allows you key in those details and it'll recommend ideal tire pressure. I knock off a couple or 3 psi from their recommendation because of our poor road surfaces. If you're riding on smooth roads their pressure recommendations are fine.

Brand_New

When it comes to tyre width do people use the actual measurement or just use the number written on the sidewall?

My wheels have a wide inner width(21mm) and when I mount a set of GP5k 25mm on them it comes to exactly 28.2mm

Am I running a 25mm or 28mm tyre?

G1032

I ride 25mm at 80psi and 28mm at 70 ish psi

I'm 73 - 74 kg

Never really get punctures. 🙈. Famous last words!!

Brand_New

G1032 wrote: »

I ride 25mm at 80psi and 28mm at 70 ish psi

The number on the sidewall of the tyre or the actual measurement?
It's hard to compare without knowing which!

magicbastarder

if people mention the width of the tyre they use, it's the width stated on the tyre, not the actual width.
the actual width can vary, commonly due to the rim they're mounted on.

Brand_New

magicbastarder wrote: »

if people mention the width of the tyre they use, it's the width stated on the tyre, not the actual width.
the actual width can vary, commonly due to the rim they're mounted on.

It can also be very different depending on the brand, so a 25mm in one brand could be closer to a 28mm in another brand. It really comes down to the inner width of the wheel used by that brand to measure.

It's interesting that someone could be talking about the advantage of running 28 over 25 and actually have the same wide as some people running 25.

kenmm

G1032 wrote: »

I knock off a couple or 3 psi from their recommendation because of our poor road surfaces.

qq- how to you measure that - I mean do you measure that accurately? Any track pump I've had, I could guestimate 3 psi, but only as in 'needle is a nudge left or right of whatever number shown'. Either I need to spend more on pumps or you use something else?

magicbastarder

i wouldn't care less either way about 2 or 3 psi. your tyres would lose that in a few days.

kenmm

magicbastarder wrote: »

i wouldn't care less either way about 2 or 3 psi. your tyres would lose that in a few days.

Ye I wouldn't normally, but current pump I find hard to read between 90 and 100 - think I've answered my own question.. new pump time!!