Comments on: 09/03/2012 – Soft Pedaling

By: Zorba

Zorba — Tue, 04 Sep 2012 04:52:27 +0000

Higher pressure (within reason) helps prevent punctures too.

By: Opus the Poet

Opus the Poet — Mon, 03 Sep 2012 23:08:26 +0000

Nevermind, I found out what happened (I should have read more carefully)

By: Opus the Poet

Opus the Poet — Mon, 03 Sep 2012 23:06:25 +0000

OK I had a comment right after the comic went up that disappeared. What happened to it?

By: Birch Creek

Birch Creek — Mon, 03 Sep 2012 22:10:26 +0000

Sure, but… I ride mostly low pressures on all my bikes, never had a pinch-flat yet. According to my experience, with a larger-volume tire, the pressure low enought to allow a pinch flat is already also low enough to let you know about it – the wheel feels “floating”, not really stable in turns, etc. Though, of course, YMMV…

By: Tencon

Tencon — Mon, 03 Sep 2012 20:05:55 +0000

As you say – we must remember that, as the linked article points out, smaller cross-section needs a higher pressure to sustain any given bump without bottoming out. Larger tyres have more air to cushion with so can absorb bumps with less deformation, as the load is spread of a larger arera/volume.

By: Tencon

Tencon — Mon, 03 Sep 2012 20:00:47 +0000

Yehuda may have a lot of stuff in his ‘Bag of Holding’ as the space inside is infinite, but it weighs no more than the emty bag. So there is no ‘load’ other than the heavy old VS frame etc. So it possibly weighs more than most mountain bikes?

By: Dondare

Dondare — Mon, 03 Sep 2012 19:10:31 +0000

Under-inflated tyres (British spelling, BTW) plus heavy load (Yehuda’s survival kit) lead to pinch-flats. So I suspect that he’s being a bit hyperbolic.

By: Kapusta

Kapusta — Mon, 03 Sep 2012 17:02:46 +0000

Riding MTB has definitely opened my eyes to running low pressure. I go with as low as I can without getting pinch-flats or the tire losing stability in turns. With 2.3′s I’m running 23 f / 27 rear.

That article about 15% tire drop also changed my view of road tire pressures. I ended up running slightly higher pressure than that article recommended, but much lower than I had been. While they “felt” slower at first, I think that is just because I was used to associating harsh=fast. But I realize that is not really the case. Back in my 23c days, I was able to drop from 120psi at both ends to 115 rear and 90 front with no measurable difference in time over distance. at ~200 lbs combined bike/rider weight I’m now running Jack Brown 33s at 55 psi front, 75 psi rear. I increase the rear for a load.

The idea that harder=faster has been pretty widely rejected in the MTB world. It is starting to be questioned by some road riders, but old ideas die hard. Obviously, you are going to want a higher psi on the road than on the trail, but as long as the surface has any irregularities, there will be a pressure at which higher psi serves no purpose, and may even be less efficient. I think that pressure is much lower than many people think.

Here is the article I was talking about: http://www.google.com/url?sa=t&rct=j&q=bicycle%20tire%2015%20drop&source=web&cd=1&cad=rja&ved=0CCAQFjAA&url=http%3A%2F%2Fwww.bikequarterly.com%2Fimages%2FTireDrop.pdf&ei=nuBEUNW_OOf96wGjzYGQBA&usg=AFQjCNGL_6p-7qkIU4Jd555EVfa1UXs5Lg

By: yolanda

yolanda — Mon, 03 Sep 2012 16:33:30 +0000

When I was a young girl I once reinflated my tire at a service station using the “thumb” method of pressure testing. I guess I blew them too high as my rear blew out on me a half block later. I learned to be more careful as I walked home the 5 miles.

By: troiker

troiker — Mon, 03 Sep 2012 16:09:46 +0000

Bizarre. I checked on the gravatar site, which showed my image. I went to the profile page on this site and re-loaded the image – and voila! Here it is!