Woah!! Tyre pressures mega low!

ct8282

Just picked up a track/stand pump today, got home and whacked it on my tyres to make sure they were properly inflated.

Well, up to this point I've been using my topeak race rocket pump to do my inflating and I have just been going on feel. Bearing in mind I've been runnning my bike like this for 3 months nearly now I was pretty gobsmacked to find that my rear tyre was at 40psi and my front at 35psi!!

2 things come to mind. How the heck did I not get a pinch flat up to now, and secondly how much quicker will I be now that my tyres are properly inflated. I have put both at 100psi so I'm hoping I notice a good improvement.

markhewitt1978

There's only one way to find out....

I suspect you might not be much faster, maybe even slower!

AchillesLeftKnee

Just be extra careful on it when you take it out. It's going to handle completely differently!

My punt is that unless you weigh very little indeed, you'll roll noticeably better.

JayKosta

It 'might be' that the guage on your new pump is not correct.

Running tires at 35-40 psi is quite low and I'd expect a 'thumb test' to easily depress the tread quite a bit. And also you might notice a lot of tire 'bulge' if you look at the tire/road when you ride at low psi.

Perhaps ask the shop where you bought the pump to check it, to make sure it is accurate.

Jay Kosta
Endwell NY USA

ct8282

5ft 8 at 78kg so not super light. I body build a lot so I'm not a lardy 78kg

ct8282

JayKosta wrote:

It 'might be' that the guage on your new pump is not correct.

Running tires at 35-40 psi is quite low and I'd expect a 'thumb test' to easily depress the tread quite a bit. And also you might notice a lot of tire 'bulge' if you look at the tire/road when you ride at low psi.

Perhaps ask the shop where you bought the pump to check it, to make sure it is accurate.

Jay Kosta
Endwell NY USA

There was a fair bit of depressing when I pressed with my thumb but not knowing any different I thought it felt hard enough and didnt want to over inflate. I did also notice a fair bit of bulge but thought it was normal-ish!

TheHound

A bit of air usually escapes when you attach the pump. Whenever I attach mine it always shows the pressures being well down on what I know they are. After 1 pump the pressure will go up by like 10-20psi.

I think it's more likely just a quirk of how the pump works.

ct8282

TheHound wrote:

A bit of air usually escapes when you attach the pump. Whenever I attach mine it always shows the pressures being well down on what I know they are. After 1 pump the pressure will go up by like 10-20psi.

I think it's more likely just a quirk of how the pump works.

I suspect you're right. But even then if they were 50-60 back and 40-50 front that's still low is it not?

Frank pole

Those pressure's do seem a bit low - I run 65 85 front/back on 25mm tyres purely for comfort over speed but have not lost too much off my average trip times

itsnotarace

35-40 psi would feel like riding in treacle and you would have to work a lot harder to maintain your usual speed

hatch87

although, it must of felt damn comfy, must of glided over pot holes without even realizing lol. Expect your backside to hurt more this time lol

ct8282

hatch87 wrote:

although, it must have felt damn comfy, must have glided over pot holes without even realizing lol. Expect your backside to hurt more this time lol

Ha ha, looking forward to getting out and seeing how much different it feels. I think, as has been said, the pressures were maybe a little higher than the initial pressure reading suggested, but now at 100psi the tyres feel like rocks in comparison with only a tiny bit of give when I press them.

Someone stated earlier that I may now be slower. Is that really possible?? Surely not!

hatch87

I would imagine so at that pressure. its a bit like have suspension, all that effort you put into the pedal is getting wasted by things compressing. Its not going to suddenly make you go twice the speed, but I would be surprised if your average isn't slightly higher