Lower Tyre Pressure- Nearly Won Over!

iron-clover

So, I've seen from a lot of threads that lower tyre pressures may actually give better rolling resistance, and better feel- after 2 weeks off I finally got out for a quick blast and put the Gatorskins to 100psi front and 110 back, rather than my standard 120psi all the way.
Wow, it made a difference! I only weigh between 67-70kgs (depending on how much racing I'm doing) and the Gatorskins always felt a little skittish at times. But on the ride yesterday through some of the Surrey Hills finest- narrow twisting, gravelly lanes- they felt a whole lot smoother, much more 'feel' and grip through the corners and just as fast as normal. If anything, they felt much more like the 4000s I keep on my racing wheels.

I will admit it did feel a little soft the odd bump, like they had a puncture- but they were fine.

I'm definitely not going back to 120psi now!

ugo.santalucia

I wouldn't get overexcited just yet, it's still exceedingly high pressure for your weight... with a modern wider rim you should be able to safely run 90 PSI at the rear with a 23 mm tyre and even less with a bigger one... they are supposed to be rubber, not wood...

dj58

I'm new to the world of 700c and high pressures, my new road bike came fitted with 23mm tyres, and after a couple of rides I swopped them for 25mm, on a standard width rim. I started off at 85F/95R, I'm 78kg, and immediately felt more confident/comfortable with the bike. I now run them at 75F/85R with latex tubes and find them to be better and I haven't noticed any decrease in my times.

I do pick my lines though and use the MTBer's technique for unweighting the bike when crossing poor road surfaces.
I think I will try some 28mm next if I have the clearance for them.

Miles253

ugo.santalucia wrote:

I wouldn't get overexcited just yet, it's still exceedingly high pressure for your weight... with a modern wider rim you should be able to safely run 90 PSI at the rear with a 23 mm tyre and even less with a bigger one... they are supposed to be rubber, not wood...

Ugo, do you have a good resource for working out recommended PSI in relation to rider weight, tyre size and rim width?

imposter2.0

ugo.santalucia wrote:

I wouldn't get overexcited just yet, it's still exceedingly high pressure for your weight... with a modern wider rim you should be able to safely run 90 PSI at the rear with a 23 mm tyre and even less with a bigger one... they are supposed to be rubber, not wood...

As above. I'm 70kg and I usually run between 80-90psi for normal road use.

Druidor

120psi for me.. 102kg so lower pressure looks a bit squidgy.

andy9964

I was 110kg when I got my bike, and only ran the 25 mm Gatorskins at 100psi.
I'm now 95kg and have GP4000s II tyres at 90-95 psi

Both tyres on std fitment Synapse wheels
Both perfectly comfortable, even on rough surfaces

kajjal

The trick is to choose a pressure that suits you. Too low you get a lot of punctures, too high and you lose grip / get a rougher ride. I weight about 100kg and have both at 105psi.

ugo.santalucia

Miles253 wrote:

Ugo, do you have a good resource for working out recommended PSI in relation to rider weight, tyre size and rim width?

There are loads of resources, but they give very different numbers, so I don't trust any of them... I can tell you what I use and I am 72-73 Kg

23 mm tyre on normal 19-20 mm rim 95-100 PSI
23 mm tyre on wide 23-25 mm rim 85-95 PSI
27 mm tyre on normal 19-20 mm rim 80-85 PSI
27 mm tyre on wide 23-25 mm rim 70-80 PSI
32 mm tyre on wide 23-25 mm rim 50-60 PSI

golfergmc

I overheard one of the Cervelo mechanics at the giro last week saying that a lot of the team were using lower pressure now as bikes have evolved over the years and become so stiff this is the only area left for the rider to try and get a bit of comfort from.

ugo.santalucia

golfergmc wrote:

I overheard one of the Cervelo mechanics at the giro last week saying that a lot of the team were using lower pressure now as bikes have evolved over the years and become so stiff this is the only area left for the rider to try and get a bit of comfort from.

They use tubulars and can go a bit lower in pressure without running the risk of pinch flats and stuff. They also use bigger tyres than they used to... 22-23 mm tubs are slowly disappearing in favour of 25-27 mm. It is a slow process, but you certainly no longer see 18-21 mm tubs at 140 PSI, as they were common in the early 90s

Moonbiker

I am 75kg & run my tyres @ 125psi

It says on the tyre wall of rubino pros 23mm 100-145 psi recommended pressure so they seems abit behind the curve still recommending really hight psi?

Can't imagine anyone has 145psi tyres apart from track riders?

19/20mm tyres used to be standard for road bikes i think?

ugo.santalucia

Moonbiker wrote:

I am 75kg & run my tyres @ 125psi

It says on the tyre wall of rubino pros 23mm 100-145 psi recommended pressure so they seems abit behind the curve still recommending really hight psi?

Can't imagine anyone has 145psi tyres apart from track riders?

19/20mm tyres used to be standard for road bikes i think?

Vittoria always recommends too high pressure for their tyres. Their CX tyres are supposed to be run at 60-90 PSI, but nobody would exceed 40 PSI in the mud and maybe 50 in the dry.

imposter2.0

Moonbiker wrote:

I am 75kg & run my tyres @ 125psi

It says on the tyre wall of rubino pros 23mm 100-145 psi recommended pressure so they seems abit behind the curve still recommending really hight psi?

Can't imagine anyone has 145psi tyres apart from track riders?

19/20mm tyres used to be standard for road bikes i think?

Those aren't 'recommended' pressures as such - just the min & max ratings used to cover their arses in case anyone makes a claim. I've run Rubinos significantly lower than 100psi withot issue. There's no reason to expect they will be any different to any other tyre.

BrandonA

I'm about 61.5 kg and I run my tyres at 125psi.

My bike/wheels are very stiff and agressive so I like to keep the pressure in the tires high as well. I've never really noticed any comfort different between 125 and 90-100 psi so I'd rather keep it high and reduce the risk of pinch punctures. Also most of my fastest rides come with the higher psi.

ugo.santalucia

BrandonA wrote:

I'm about 61.5 kg and I run my tyres at 125psi.

Also most of my fastest rides come with the higher psi.

Does it mean that regularly you also do rides at lower PSI and they are slower, or its just one of those controversial statements for the sake of it?

sloppyschleckonds

BrandonA wrote:

IAlso most of my fastest rides come with the higher psi.

Have you tried tubulars? I run mine at around 130psi and most of my fastest rides come with the higher psi.

littledove44

Tire Width=20: Pressure(psi) = (0.33 * Rider Weight in lbs) + 63.33
Tire Width=23: Pressure(psi) = (0.33 * Rider Weight in lbs) + 53.33
Tire Width=25: Pressure(psi) = (0.33 * Rider Weight in lbs) + 43.33
Tire Width=28: Pressure(psi) = (0.33 * Rider Weight in lbs) + 33.33
Tire Width=32: Pressure(psi) = (0.17 * Rider Weight in lbs) + 41.67
Tire Width=37: Pressure(psi) = (0.17 * Rider Weight in lbs) + 26.67

drlodge

77kg here and running Michelin Pro4 SC at around 120psi rear, 110 psi front, may be tad softer. Pumped my Vittoria Corsa EV CX tubs to the same pressure yesterday. I like em' good n hard

matt-h

76kgs 23mm rims, 25mm Veloflex clincher 90front 100rear. Very comfy.

Matt

dizarch

I'm a rare old lard arse (approx 100kg) running 4000's at 120psi which I find very comfortable especially after being properly fitted for the bike.

DavidJB

Haha at this thread. You need a bloody PHD in maths now to inflate your tyres...just pump them up and go riding.

drlodge

DizArch wrote:

I'm a rare old lard ars* (approx 100kg) running 4000's at 120psi which I find very comfortable especially after being properly fitted for the bike.

You're tyres will be spent once you've done the 50x50 rides, then you can replace your Conti's with some decent tyres ;-)

Serious Cat

80kg here and my gatorskins are 100 front 105 rear. Ive tried 120 on both and I could feel my fillings vibrating as it was obscenely harsh.

iron-clover

drlodge wrote:

DizArch wrote:

I'm a rare old lard ars* (approx 100kg) running 4000's at 120psi which I find very comfortable especially after being properly fitted for the bike.

You're tyres will be spent once you've done the 50x50 rides, then you can replace your Conti's with some decent tyres ;-)

And GP 4000s aren't decent tyres? I find this surprising...

Serious Cat

iron-clover wrote:

drlodge wrote:

DizArch wrote:

I'm a rare old lard ars* (approx 100kg) running 4000's at 120psi which I find very comfortable especially after being properly fitted for the bike.

You're tyres will be spent once you've done the 50x50 rides, then you can replace your Conti's with some decent tyres ;-)

And GP 4000s aren't decent tyres? I find this surprising...

Ive read very many suggestions that gp4000s puncture easily, whereas conti gatorskins do not.

drlodge

iron-clover wrote:

drlodge wrote:

DizArch wrote:

I'm a rare old lard ars* (approx 100kg) running 4000's at 120psi which I find very comfortable especially after being properly fitted for the bike.

You're tyres will be spent once you've done the 50x50 rides, then you can replace your Conti's with some decent tyres ;-)

And GP 4000s aren't decent tyres? I find this surprising...

I was kidding, the Contis are fine. But should you get a chance, try the Vittoria Open Corsa CX or Pave tyres, these are significantly faster and give a great ride but only use when its fine. They make the Contis feel like hosepipes.

mfin

drlodge wrote:

I was kidding, the Contis are fine. But should you get a chance, try the Vittoria Open Corsa CX or Pave tyres, these are significantly faster and give a great ride but only use when its fine. They make the Contis feel like hosepipes.

I agree the feel of Open Corsa CX is better than GP4000s, but, you say they are "significantly faster", how much faster are they really? So, significantly = ???

drlodge

The only bit of evidence I have with the Open Pave, is that I rode a 70 miler to my Dads (Woking to Milton Keynes) last year and I averaged 19mph. That's a record for me, on this distance I would normally reckon 17+ mph is good. OK I was pegging it, but even so, that's a damn good average I may say (for me).

I mate has just bought the Open Corsa and he averaged 19.5 mph doing his commute from Woking to London, I normally average about 16mph. OK he's faster than me but again, this is quite some speed considering the last 10 miles (from Richmond Park) are in London and hence quite slow moving.

I also have the Corsa EVO CX tubuluars fitted to my 50mm carbon wheels, went out on Sunday and they really flew. Obviously this is also down to the wheels, but the tyres are a part of that.

I just find them lovely feeling, fast tyres. But they do cut up quite easily compared to GP4000S/Pro4 SC and so are only for "best".

ugo.santalucia

I seem to go always at the same speed... even with cyclocross tyres... :roll:

Still, faster than Drlodge...

mfin

drlodge wrote:

The only bit of evidence I have with the Open Pave, is that I rode a 70 miler to my Dads (Woking to Milton Keynes) last year and I averaged 19mph. That's a record for me, on this distance I would normally reckon 17+ mph is good. OK I was pegging it, but even so, that's a damn good average I may say (for me).

I mate has just bought the Open Corsa and he averaged 19.5 mph doing his commute from Woking to London, I normally average about 16mph. OK he's faster than me but again, this is quite some speed considering the last 10 miles (from Richmond Park) are in London and hence quite slow moving.

I also have the Corsa EVO CX tubuluars fitted to my 50mm carbon wheels, went out on Sunday and they really flew. Obviously this is also down to the wheels, but the tyres are a part of that.

I just find them lovely feeling, fast tyres. But they do cut up quite easily compared to GP4000S/Pro4 SC and so are only for "best".

I agree they feel good, but I think if that's your reasoning for them being "significantly faster" then it's not in the slightest bit scientific! If you think a Pave vs a 4000s can be the reason for a 19mph vs 17.something over 70miles then you're in cloud cuckoo land.

Offering "mate has just bought the Open Corsa and he averaged 19.5 mph doing his commute from Woking to London, I normally average about 16mph. OK he's faster than me but again, this is quite some speed considering the last 10 miles (from Richmond Park) are in London and hence quite slow moving." as any evidence of a tyre being 'significantly faster' is nothing short of funny.

You can't claim the tyres are "significantly faster" based on this stuff!