tomato coupe

Clouds. So many clouds. So little time.

PeteHski

Well I could set my tyre pressures randomly and probably not have any “serious” issues, but why not take advantage of the info? It takes about 10 seconds to use a pressure calculator and then you have a good starting point to work from. I found it most useful when I went to wider tyres and rims last year. Saved a load of guesswork, trial and error.

wolfchild

You don't need to be as exact with bicycle tire pressures as you are with your vehicle tire pressures. A bicycle tire can be easily checked by squeezing it with your fingers or even sitting on your bicycle, can't do the same to a vehicle tire...or just use a pressure gauge and go by the recommended pressure that is written on the sidewall of your bicycle tires, no need for any online calculators....I've run my bike tires between 15-20 PSI during winter without any negative effects, I couldn't do the same on my pick-up truck because it would be a safety risk.

smd4

I just look at my sidewall. Takes even less than 10 seconds.

PeteHski

Fine if you want to run max pressure regardless of your weight.

PeteHski

We once lived in caves without running water and electricity.

smd4

What have I been saying this whole time?

79pmooney

I gotta go read labels on my current tubulars. I forget which one has the 115-200 psi but it's there. I think it's the Vittoria G+ 28c but it might be a Veloflex. In any case, a very high quality tire and that label means they are standing behind the casing, stitching and details being that good. Tires of the same quality but far smaller, like 20c or less are used on the velodrome at well over 160 and have been forever. (They blow out like a pistol shot.)

And the great thing about tubulars at those pressures is there is no rim sidewall to blow out. The rims simply don't care. 400 psi would work just fine as far as they are concerned.

Atlas Shrugged

I feel sorry for any new sport cyclist who may stumble upon this bike forum in general seeking an answer to any particular question. Any reasonable contemporary response gets drowned out by the same characters who are living out of a 1975 Bicycling Magazine. Riding around on tubulars at 140 psi or just pump to the sidewall max rating is just not done by any informed cyclist who is following current best practice. It’s been long proven that those high pressures are slower and exponentially more uncomfortable yet the myth persists and promoted by a vocal few. High pressure leads to less flats is another fallacy long disproven. By the way if flats are the problem just go tubeless and ride in comfort but that would start that cloud yelling extravaganza all over again.

tFUnK

This thread is hilarious, hard to tell if people are just trolling.

Setting pressures to the max on the label - sure you can ride the thing and not get a pinch flat, but is it optimal?

Doing it by feel - what's the limit of one's perception? Can you tell a 10psi difference by pinching? A 10psi difference can be the difference between pinch flatting and not, or the difference between a supple ride or a harsh ride.

Use one of the several dozen calculators out there that does most of the work for you (factoring in your weight, tire size, riding situation) and fine tune from there. Or don't 🤷‍♂️

Traditional wisdom suggests to follow what on the tire label. I think we can agree that modern wisdom suggests going as low as you can without pinch flatting. How you get there, whether through trial and error, asking the internet, or using a calculator, is up to you.

Chuck M 

Meanwhile the OP is still wondering if they are inflating their tires correctly...

PeteHski

I'll leave it to the OP whether or not to follow your advice. It's simple, I'll give it that.

smd4

How in the world did you reach the conclusion that I “gave advice?”

PeteHski

Yet again, you fail to understand that not everyone does things the way you do. No common sense has been replaced here. Online calculators are not the work of the devil. They just make it a bit easier to optimise your tyre pressures if you can be bothered.

The OP asked for advice about optimal tyre pressures. Someone pointed to a well-known online pressure calculator and then you and a few others have to troll it as a dumb idea, just because you do things the old way as if that's the holy grail.

PeteHski

I thought your advice was to set your pressure to whatever it says on the sidewall? Otherwise why even bother to reply to the question?

smd4

Clearly you misread my posts. I only gave my opinion on what I prefer. If the OP, as you, construes this as advice, then that is his prerogative.

shelbyfv

Obviously OP got the help he needed in the first response. He didn't need to stay around for the clown show.

badger1

I think it is time this thread -- well, at least one strand of it -- had its own theme song.

smd4

You can't be serial? The "use-a-calculator, run-low-pressure on ultra-wide-tires for comfort and speed" crowd is far largerthan the two or three of us heretics, no matter how "vocal" you think we are. The "new sport cyclists" will easily see that the vast majority of posts on this thread and others like it are, ahem, "reasonable contemporary responses."

I don't think you need to worry about new cyclists.

shelbyfv

I agree. Easy to separate grain from chaff in this thread.

DaveSSS 

Sounds like all of the correct information might not have been used. Either that or you didn't give it a reasonable try. I've used the calculator with all of my different rim and tire widths. I have the most modern 25mm internal width hookless rims with smallest allowed 28mm tires. For a 140 lb rider, it suggests 52/56 psi. It works great. If I used 32mm tires it suggests 45/48.

With my rims, it suggests 58/61 for a 250 lb rider. If a more common 19mm hooked rim is used, it suggests 62/66 for a 200 lb rider.

PeteHski

This is what I like most about that calculator. I have wheel sets with internal widths of 17 mm and 22 mm, along with various tyres from 28 to 32 mm width. It makes it easy to adjust pressures for all the combinations of rim and tyre I use and the differences are significant. For 28C tyres on 17 mm rims it suggests pressures of 72/77 psi. For 32C on 22 mm rims it suggests 57/61 psi for the same conditions. Having run both these combinations, they felt good at those pressures. I also double check against any specific tyre manufacturer pressure recommendations - to see if they are suggesting a wildly different setting. For my Pirellis I think they suggested slightly higher pressures, but their chart didn't have my exact rim widths (they quote for 19 and 21 mm rim widths with 6 kg weight increments). My Contis only suggest maximum pressures (73 psi in this case for 30C tyres)

terrymorse 

I don't know if "going as low as you can without pinch flatting" is the prevailing wisdom, but if it is, it's not wise.

If the road surface is good and without potholes, you can use a quite low tire pressure without the fear of a pinch flat. But that low pressure will almost certainly have high rolling resistance, produce greater tire wear, and reduce the handling.

DaveSSS 

The sram calculator does NOT suggest a pressure likely to pinch flat. Tubed setups need much more pressure than tubeless and hookless goes even lower than hooked. I just got my second pair of BTLOS 25mm IW hookless rims that require no rim strip today. Swapped 28mm tires from my previous Fulcrum racing 3 wheels. Pressure will be 10 psi lower.

Atlas Shrugged

Perhaps in 1975 but not anymore. Like everyone likes to say “follow the science”.