[Shanefutcher]

Hi I’ve been riding for about 2 years now and always have my tyre pressure at 105psi.should I have more in there

Topic

[700c]

Calculator is all well and
Calculator is all well and good if you have decent tyres which will handle , for example, 140 psi on the rear, but when that exceeds the manufacturers recommendation, or even that specified for the rim, it’s probably not a good idea

Handmade tubular type with high thread count will work, but not much else

And no, I don’t think going up to a bulging 25 or 28 is what I want to do when I’ve spent loads on an aero wheelset!

Still,, seems to justify my high pressures for the rear, though says my front needs to be reduced

[paulfg42]

I’m bemused by the science
I’m bemused by the science and the calculator. 🙁

I currently inflate both tyres to 90. What am I doing wrong?

[Sensible]

I am 86 kg and have an 8kg
I am 86 kg and have an 8kg Giant TCR Advanced. I have 23c Giant P-SLR 1 tyres. (Giants top tyres with different compound front and rear) The max pressure is 120psi and I have been running at 110 psi. A few months ago I came off the bike in the wet when the rear end slid away from me. Still recovering from a wrist injury. Are my tyre pressures too high?

[Sensible]

Shanefutcher wrote:It says

Shanefutcher wrote:

It says that you should change the tyres.i slid off my bike with giant p-slr tyres and think they’re awful in wet conditions

What is it that says I should change my tyres?

I have only done 800 miles on them and they are almost worn down to the indicator, so will change them in the next few months anyway. Going to get Conti GP 4000S, having seen good reviews.

I have just worked out what my pressures should be using the 15% drop chart. It saysvI should have my front at 90 and my rear at 140. Considering tge max is 120 I wont be going to 140.

[Shanefutcher]

It says that you should
It says that you should change the tyres.i slid off my bike with giant p-slr tyres and think they’re awful in wet conditions

[BBB]

Hector Ch wrote:According to

Hector Ch wrote:

According to that, I’m supposed to have 9.5 Bar in my tyres. Only problem is, my Conti 4000 S tyres say max pressure of 8.5 bar…

Wonderful…

What this is clearly telling you is that you need wider tyres.

[Mr Will]

Here’s an online calculator
Here’s an online calculator based on the 15% drop method: http://www.dorkypantsr.us/bike-tire-pressure-calculator.html

Works well IME

[Hector Ch]

According to that, I’m
According to that, I’m supposed to have 9.5 Bar in my tyres. Only problem is, my Conti 4000 S tyres say max pressure of 8.5 bar…

Wonderful…

[goldtop]

BBB wrote:KiwiMike wrote:NO.

BBB wrote:

KiwiMike wrote:

NO. Not unless you are on 23c’s and weigh 100kg. Follow this PDF, it’s science. Anyone else is wrong.
http://www.bikequarterly.com/images/TireDrop.pdf
Your arse, hands and times will thank you.

+1

That’s definitely the best method available, at least as a starting point but it seems like science isn’t very much in nowadays 😉

Please stop blindly following manufacturers’ recommendations people.

As a roadie noob I can also say I feel more comfortable following the pressures in this guide and haven’t noticed any loss in speed.

The difference when applying the drop to my Bad Boy is much more pronounced and was a bit of a revelation for me. Much smoother and noticeably quicker than using mfrs recommended pressures!

[BBB]

KiwiMike wrote:NO. Not unless

KiwiMike wrote:

NO. Not unless you are on 23c’s and weigh 100kg. Follow this PDF, it’s science. Anyone else is wrong.
http://www.bikequarterly.com/images/TireDrop.pdf
Your arse, hands and times will thank you.

+1

That’s definitely the best method available, at least as a starting point but it seems like science isn’t very much in nowadays 😉

Please stop blindly following manufacturers’ recommendations people.

[Simon E]

Al, I’d suggest your
Al, I’d suggest your pressures sounds about about right for your weight. You and Shane should try 10 psi either side of what you run now and see how it feels, establish what suits you.

[pdows47]

Get the Vittoria Ityre
Get the Vittoria Ityre pressure app, gives you ideal pressure based on the tyre and conditions. It is intended to work with vittoria tyres, but you can get it to work pretty well for other brands

[Al'76]

Hi KiwiMike,
According to
Hi KiwiMike,
According to this I’m running my tyres with way too much pressure; combined weight of rider and bike is around 79kgs and, on 23mmm tyres, I run 100psi in the front and 110psi in the rear. Manufacturer recommends 115 to 125psi, so I’m below that already. Any idea why the manufacturer specifies such high pressures?

[spongebob]

Vittoria do an app for their
Vittoria do an app for their tyres, I think on the open corsa I ended up running 120/115 in dry smooth conditions and 5-10 lower in wet/rough

[therevokid]

KiwiMike

KiwiMike wrote:

http://www.bikequarterly.com/images/TireDrop.pdf

Read this, worked out what my bike would need …… and
found the front would be below manufacturers recommended
minimum (rear is just on the limit !!)

[Author]

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