Actual bike tech alert: New inner tube

http://www.bikebiz.com/news/read/pro...er-tube/018702

I won't be rushing out to buy any.

--
JS

On Wednesday, November 18, 2015 at 12:37:42 PM UTC-8, James wrote:
http://www.bikebiz.com/news/read/pro...er-tube/018702

I won't be rushing out to buy any.

Nice and light. This will help MTB's because they are so damned heavy. But what are the other attributes of these tubes? Are they more difficult to puncture? And on a road bike on a fast descent the TIRE can heat almost to the point that rim brakes heat the rims to.

Disks are a bad idea on street bikes because they have low rolling resistance and disks ALWAYS drag some.

I have just finished my Ridley Xbow and was trying it out yesterday. I hadn't set the cantilever return springs tight enough to not touch the VERY slight wobble in the front rim. So while in the shop it all worked perfect - out on the trail it touched slightly.

When I got home after just 20 miles I was about to collapse. I sat down and it took 20 minutes before I could do anything. So this almost negligible drag of the disk shoes isn't anything to sneer at. And while you can set road rim brakes to never touch you can't do this with a disk. If they can't do it on cars they sure as heck aren't going to go it on bicycles. Remember that the shoe is separate from the piston and the rolling vibration will always have it touching. This is why disk shoes wear so rapidly.

Now because of the way they are designed with disk brakes counter actuating on a solid surface vs. rim brakes actuating against a flexible rim, disk brakes have FAR superior stopping power if you don't melt aluminum disks into a puddle. But it will remain to be seen if the stopping power makes up for the increases rolling resistance.

Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?

On Wed, 18 Nov 2015 14:36:45 -0800 (PST), Doug Landau
wrote:


Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?


But don't worry as the original poster stipulated that they have "low"
rolling resistance :-)
--

Cheers,

John B.

On Wednesday, November 18, 2015 at 2:36:47 PM UTC-8, Doug Landau wrote:
Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?

Doug - this is a tech group. I expect you not to be thick. A street bike is supposed to have a very low rolling resistance. Is that something you didn't know?

On Friday, November 20, 2015 at 3:32:58 PM UTC-8, wrote:
On Wednesday, November 18, 2015 at 2:36:47 PM UTC-8, Doug Landau wrote:
Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?

Doug - this is a tech group. I expect you not to be thick. A street bike is supposed to have a very low rolling resistance. Is that something you didn't know?

Hmmm. Rolling resistance refers to the rolling friction or rolling drag of the tire against the ground. It has nothing to do with disc brakes.

I've been riding with mechanical discs for close to ten years on my commuter bike, and I hadn't noticed any additional wheel drag -- until I added a dyno hub. By wheel drag, I mean when I spin the wheel, it seems to keep turning like any other non-disc wheel. I can't comment on whether there is additional aerodynamic drag on the bike as a whole -- and of course, this assumes the brakes are properly adjusted, and the pads are not dragging on the disc.

-- Jay Beattie.

On 11/20/2015 4:59 PM, jbeattie wrote:
On Friday, November 20, 2015 at 3:32:58 PM UTC-8, wrote:
On Wednesday, November 18, 2015 at 2:36:47 PM UTC-8, Doug Landau wrote:
Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?

Doug - this is a tech group. I expect you not to be thick. A street bike is supposed to have a very low rolling resistance. Is that something you didn't know?

Hmmm. Rolling resistance refers to the rolling friction or rolling drag of the tire against the ground. It has nothing to do with disc brakes.

I've been riding with mechanical discs for close to ten years on my commuter bike, and I hadn't noticed any additional wheel drag -- until I added a dyno hub. By wheel drag, I mean when I spin the wheel, it seems to keep turning like any other non-disc wheel. I can't comment on whether there is additional aerodynamic drag on the bike as a whole -- and of course, this assumes the brakes are properly adjusted, and the pads are not dragging on the disc.

I have mechanical discs on one bike in the fleet. Of course there is no
extra rolling resistance. Unless the poster was referring to the
additional mass of the disc that is present on the wheel versus using
the rim surface for braking.

I have a wheel with an Arai drum brake for our tandem. I rarely use it.
I thought we would do some loaded touring on the tandem where it would
be necessary but that never happened. The one tour I did with it was in
Russia where we had a sag wagon that carried our gear and the vodka.

On Friday, November 20, 2015 at 4:59:03 PM UTC-8, jbeattie wrote:
On Friday, November 20, 2015 at 3:32:58 PM UTC-8, wrote:
On Wednesday, November 18, 2015 at 2:36:47 PM UTC-8, Doug Landau wrote:
Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?

Doug - this is a tech group. I expect you not to be thick. A street bike is supposed to have a very low rolling resistance. Is that something you didn't know?

Hmmm. Rolling resistance refers to the rolling friction or rolling drag of the tire against the ground. It has nothing to do with disc brakes.

I've been riding with mechanical discs for close to ten years on my commuter bike, and I hadn't noticed any additional wheel drag -- until I added a dyno hub. By wheel drag, I mean when I spin the wheel, it seems to keep turning like any other non-disc wheel. I can't comment on whether there is additional aerodynamic drag on the bike as a whole -- and of course, this assumes the brakes are properly adjusted, and the pads are not dragging on the disc.

Jay, I expect you as well to actually read something before you write. A street bike is supposed to have low rolling resistance. ANYTHING that adds friction through any medium reduces that rolling resistance.

On a heavy full suspension bike with knobbies, the additional friction of a dragging disk doesn't add much in comparison to all of the other drags but on a street bike designed for minimum AIR resistance, tire rolling resistance and every other source of resistance at a bare minimum, the addition of a slight disk drag is quite pronounced.

Have you even ridden a disk bike?

On 11/19/2015 9:31 PM, Phil W Lee wrote:
Doug Landau considered Wed, 18 Nov 2015
14:36:45 -0800 (PST) the perfect time to write:


Disks are a bad idea on street bikes because they have low rolling resistance

Disk brakes have rolling resistance?

In use, yes.
It's kinda the point

There's no reason that a properly aligned and adjusted disk caliper
should drag any more than a properly aligned and adjusted rim caliper
when released.

I've never owned a disk brake bike, but I've ridden several that
belonged to others. Some definitely made scraping sounds with the brake
off. One tourist who had ridden 60 miles that day to get to my house
assured me that the scraping was "normal."

I can't say how much drag it imposed; my ride was a short one, testing
an unrelated repair I made for him. But I know the scraping would have
driven me nuts.


--
- Frank Krygowski

On 20/11/2015 03:15, Frank Krygowski wrote:
On 11/19/2015 9:31 PM, Phil W Lee wrote:
Doug Landau considered Wed, 18 Nov 2015
14:36:45 -0800 (PST) the perfect time to write:


Disks are a bad idea on street bikes because they have low rolling
resistance

Disk brakes have rolling resistance?

In use, yes.
It's kinda the point

There's no reason that a properly aligned and adjusted disk caliper
should drag any more than a properly aligned and adjusted rim caliper
when released.

I've never owned a disk brake bike, but I've ridden several that
belonged to others. Some definitely made scraping sounds with the brake
off. One tourist who had ridden 60 miles that day to get to my house
assured me that the scraping was "normal."

I can't say how much drag it imposed; my ride was a short one, testing
an unrelated repair I made for him. But I know the scraping would have
driven me nuts.

Knobblies hide the sound :-)

Ours sometimes seem to scrape - but spinning the wheel shows it's not
actually dragging. I think the scraping goes away after a short while
anyway - I certainly don't remember being bothered by it.