I've used a set of Tuffies in my old road bike tires for about ten years, and have had virtually no problems with flats. I don't really mind the added weight. I want to put some on the new road bike I'm getting and am wondering what the current recommended versions are.
On Thu, 14 Apr 2005 23:30:12 -0700, "Magnusfarce" <magnusfarce@adelphia.net> wrote:
I've used a set of Tuffies in my old road bike tires for about ten years,>and have had virtually no problems with flats. I don't really mind the>added weight. I want to put some on the new road bike I'm getting and am>wondering what the current recommended versions are.>
- Magnusfarce>
Dear Magnus,
It isn't so much the added weight as the extra rolling resistance that many people consider a drawback. Basically, you're riding on an added layer of soggy plastic and constantly deforming it. It doesn't spring back well, which is why tires aren't made of plastic.
If the new bike and the old bike use roughly the same tires, and you're happy with the old bike, you might try just putting your old liners in the new bike's tires.
Tuffy strips are solid plastic and give better protection against things like small thorns than woven Kevlar liners, which are now sometimes incorporated in tires--pointy stuff pierces anything woven.
If you're expecting lots of flats from glass or sharp rock chips, you might look into a set of tires with built-in Kevlar.
(I note with civic pride a comment from a disgruntled touring rider who purchased his liners in "Peublo, CO" to stop thorns.)
And there's the obvious www.mrtuffy.com, but it seems to be having internet hiccups.
If you like 'em, buy the suggested width. Their chief competitor seems to be SpinSkins. If you keep the old bike, you might try running one bike for a while without them to see whether they're really needed after ten years. You might be lucky enough to be riding now where flats are rare.
Magnusfarce wrote:> I've used a set of Tuffies in my old road bike tires for about ten years,> and have had virtually no problems with flats. I don't really mind the> added weight. I want to put some on the new road bike I'm getting and am> wondering what the current recommended versions are.>
- Magnusfarce>
why not just buy puncture resistant tires??? i've had awesome ZERO puncture results this winter with kevlar belted hutchinsons whereas others have punctured once or twice per rain ride.
On 15 Apr 2005 09:38:51 -0700, "Bruce Jackson" <b.a.jackson@ieee.org> wrote:
carlfogel@comcast.net wrote:>
It isn't so much the added weight as the extra rolling>> resistance that many people consider a drawback.>
True so far.>
Basically,>> you're riding on an added layer of soggy plastic and>> constantly deforming it. It doesn't spring back well, which>> is why tires aren't made of plastic.>
I believe the second part is incorrect. Polyurethane (the plastic>Mr. Tuffy's are made of) can have very good rebound. It is true>that adding any material to a tire should increase hysteresis losses>but polyurethane is one of the better choices of materials.>
Polyurethane pneumatic tires have been tried. The material has a lot>of very promisng properties but wet traction was the biggest problem.>Ever try to roller skate on wet roads?>
Getting back to the subject at hand. I'd never put Mr. Tuffys on a>bicycle I use recreationally but I've used them on my commuter bike>and went years between flats. When I'm using my bike for>transportation avoiding flats is more important than rolling>resistance.
Dear Bruce,
D'oh! You may well be right.
I blathered without thinking of anything except rolled-up Mr. Tuffy polyurethane liners, which are soggy. But that's probably more the flexible, loosely-packed layers--a similar long thin strip of tire rubber rolled-up would probably be much soggier than a real tire.
Now I have to go and look around for rolling resistance of polyurethane versus tire rubber.
Luckily, my main point survives even my material ignorance in that any extra layer of material will increase rolling resistance.
<carlfogel@comcast.net> wrote: (clip) any extra layer of material will increase rolling resistance. ^^^^^^^^^^^^^^ I'm not sure that is true, either. Try to visualize the effect of a metal hoop between the tube and tire. That might actually DECREASE the amount that the tread squirms. That's probably why steel-belted radial auto tires produce better gas mileage. I realize that this is becoming an academic argument, but then, you seem to be an academic kind of guy.
<carlfogel@comcast.net> wrote: (clip) any extra layer of material will >increase rolling resistance.>^^^^^^^^^^^^^^>I'm not sure that is true, either. Try to visualize the effect of a metal >hoop between the tube and tire. That might actually DECREASE the amount >that the tread squirms. That's probably why steel-belted radial auto tires >produce better gas mileage. I realize that this is becoming an academic >argument, but then, you seem to be an academic kind of guy.
Dear Leo,
Hmmm . . . I'm intrigued, but how would an interior metal tire liner reduce the hysteresis of the rubber?
It would just press against the inside of the tire, like the inner tube pressing against it.
You could be right, but I have a vague notion that it's the radial (versus cross) ply design that accounts for less rolling resistance in car tires.
Luckily, we have a number of posters who know lots about such things, so they may explain whether it's the steel in the belts or the radial construction.
As for the academic nature of the topic, those are usually the most interesting ones. As a practical matter, almost anything with two wheels and pedals works surprisingly well.
<carlfogel@comcast.net> wrote: Hmmm . . . I'm intrigued, but how would an interior metal tire liner reduce the hysteresis of the rubber? ^^^^^^^^^^^^^^^ In a conventional setup, with no liner, the tread deflects until the pressure x area is sufficient to support the load. Introducing a stiffener between the tube and tire would spread the tire load onto a larger area of the tube, resulting is less deflection. Less deflection--less hysteresis loss. I see it as being equivalent to raising the tire pressure.
^^^^^^^^^>In a conventional setup, with no liner, the tread deflects until the >pressure x area is sufficient to support the load. Introducing a stiffener >between the tube and tire would spread the tire load onto a larger area of >the tube, resulting is less deflection. Less deflection--less hysteresis >loss. I see it as being equivalent to raising the tire pressure. >
this may be so. I have a little hill I coast down every bike ride. I have used it to test tire speed. I tired this last tire right off with a tuffy and now that I have removed it (long story) so far I have not seen a speed increase and may have seen a bit of decrease. not really positive about this but there was no increase when it was removed.
-- Knight-Toolworks & Custom Planes Custom made wooden planes at reasonable prices See http://www.knight-toolworks.com For prices and ordering instructions.
<carlfogel@comcast.net> wrote in message news:aqou51dfg7fhg3r2g3ee1n5b69den158ro@4ax.com...> On Thu, 14 Apr 2005 23:30:12 -0700, "Magnusfarce"> <magnusfarce@adelphia.net> wrote:>
And there's the obvious www.mrtuffy.com, but it seems to be> having internet hiccups.>
Yeah the site seems to be having some sort of a break down. Do they make them for older sized tires? i.e. 26x1&3/8? Ken
But I suspect that top speed rolling down a hill will vary>from run to run depending more on the breeze than a tire>liner.>
I test this over weeks of time and just notice the top speeds I can get coasting down this hill. it's about as accurate as I can get in life. I started testing tires for speed. this is on my bent. I went from a 85psi 1.5" rear tire to a specialized armadillo 1.5" at 100 psi and gained 2mph. the front I went from a lower psi to 100 psi and gained another 1.5mph. but going to a skinnier front wheel made no difference and going from the 1.5" to a 1" 120psi tire made no difference either for some weird reason.
-- Knight-Toolworks & Custom Planes Custom made wooden planes at reasonable prices See http://www.knight-toolworks.com For prices and ordering instructions.
On Sat, 16 Apr 2005 10:19:16 -0700, Steve Knight <stevek@knight-toolworks.com> wrote:
But I suspect that top speed rolling down a hill will vary>>from run to run depending more on the breeze than a tire>>liner.>>
I test this over weeks of time and just notice the top speeds I can get>coasting down this hill. it's about as accurate as I can get in life. > I started testing tires for speed. this is on my bent. I went from a 85psi>1.5" rear tire to a specialized armadillo 1.5" at 100 psi and gained 2mph. the>front I went from a lower psi to 100 psi and gained another 1.5mph. but going>to a skinnier front wheel made no difference and going from the 1.5" to a 1">120psi tire made no difference either for some weird reason.
Dear Steve,
I'd expect a slight improvement from an increase of 15 psi, and maybe more from switching to a different brand of 1.5" tire.
One thing that might confuse matters is when the testing was done. For example, if you recently tested the old setup for weeks in colder winter weather, and the new one in warmer spring weather, the stinking temperature difference can account for much of the 2 mph difference.
Similarly, time of day--in most places, it's calm in the morning and gets windier during the day.
Or the damned barometric pressure--and so on. All the annoying little details that we don't notice add up. (I'm absurd, but even I draw the line at recording the mercury reading before my daily ride--"terrible headwind out" usually explains why I was down to 14 mph where I usually hit 24 mph.)
As for the skinnier front wheel, if it was just a narrower rim with the same width tire, then a lack of improvement would be reasonable--the tire stayed the same width, and the spokes stuck out as much.
Notice that narrowing your tire from 1.5" to 1" seemed to make no difference in a short coasting test. Physics suggests that in isolation it should have improved things by reducing wind drag, but the chances of isolating that small a single improvement from the simultaneous effects of wind, temperature, barometric pressure, and so forth are small.
You can confirm how little difference a narrower front tire would make on a recumbent with the familiar calculator:
Just select lowracer recumbent as your bike type, take the defaults, and you'll get 23.1 mph for 160 watts on the level. Change the front tire to medium-wide high pressure slick, try again, and--
Same 23.1 mph.
Fatten the front tire up another notch to a wide high pressure slick and--
Aha! Speed drops . . . to 23.0 mph.
Let's skip down to the bottow and put a 1.75 off-road knobby of the front of your imaginary low-racer . . .
Predicted speed drops to 21.8 mph, a whole 1.3 mph lower than with the best narrow high pressure tire.
You can check that the calculator really is paying attention by noting the frontal area and rolling resistance values in the lower red boxes. They do change, but not enough to make much speed difference.
I think that you'll get much the same results, with a handy table of far more detailed rolling resistance values for recumbent tires, here:
The good news is that your frustrating "for some weird reason" results are a sign of good faith--it would be suspicious if our crude real-life tests unfailingly showed such tiny improvements. I sympathize, since I often see such odd results when I'm expecting improvements (and vice-versa). Nevertheless, it's fun to keep testing such things in hopes of understanding them better.
On Sat, 16 Apr 2005 08:50:09 -0400, "Ken" <kcmarcet-dispose-trash@hotpop.com> wrote:
<carlfogel@comcast.net> wrote in message>news:aqou51dfg7fhg3r2g3ee1n5b69den158ro@4ax.com...>> On Thu, 14 Apr 2005 23:30:12 -0700, "Magnusfarce">> <magnusfarce@adelphia.net> wrote:>>
And there's the obvious www.mrtuffy.com, but it seems to be>> having internet hiccups.>>
Yeah the site seems to be having some sort of a break down. Do they make>them for older sized tires? i.e. 26x1&3/8?>Ken
Dear Ken,
Yes, the site still won't work for me.
And yes, Mr. Tuffy strips are available for 26 x 1&3/8:
<carlfogel@comcast.net> wrote in message news:7cr2619mam76pfivus44hci6ha120l88eu@4ax.com...> On Sat, 16 Apr 2005 08:50:09 -0400, "Ken"> <kcmarcet-dispose-trash@hotpop.com> wrote:>
<carlfogel@comcast.net> wrote in message> >news:aqou51dfg7fhg3r2g3ee1n5b69den158ro@4ax.com...> >> On Thu, 14 Apr 2005 23:30:12 -0700, "Magnusfarce"> >> <magnusfarce@adelphia.net> wrote:> >>
And there's the obvious www.mrtuffy.com, but it seems to be> >> having internet hiccups.> >>
Yeah the site seems to be having some sort of a break down. Do they make> >them for older sized tires? i.e. 26x1&3/8?> >Ken>
Dear Ken,>
Yes, the site still won't work for me.>
And yes, Mr. Tuffy strips are available for 26 x 1&3/8:>
<carlfogel@comcast.net> wrote: (clip)Physics suggests that in isolation it should have improved things by reducing wind drag, but the chances of isolating that small a single improvement from the simultaneous effects of wind, temperature, barometric pressure, and so forth are small.(clip) ^^^^^^^^^^^^ Leo: This plays into the physics of testing for the effects of tire liners by measuring very high downhill speed. Wind drag force goes up approximately as the square of the speed, so at maximum downhill speed, nothing else really matters. Rolling resistance is probably fairly constant (I think), so it becomes insignificant compared to wind drag. Therefore, if you are doing coasting tests to judge rolling resistance changes, I suggest going to the other end of the scale. Find a gradient that produces a speed of only a few MPH, and do the tests there. Wind drag will by relatively small. Variations in rolling resistance should show up better in your top speed. ^^^^^^^^^^^^^^^ Carlclip)I often see such odd results when I'm expecting improvements (and vice-versa). (clip) ^^^^^^^^^^^^^^ Leo: The reason for double-blind tests.
The good news is that your frustrating "for some weird>reason" results are a sign of good faith--it would be>suspicious if our crude real-life tests unfailingly showed>such tiny improvements. I sympathize, since I often see such>odd results when I'm expecting improvements (and>vice-versa). Nevertheless, it's fun to keep testing such>things in hopes of understanding them better.
lots of good info. this is more fun then anything else. I was surprised with the first 2mph increase with only a PSI and different brand of tire. so silly me to expect it going to smaller tired and higher pressure (G) yes the temp and everything sure makes a difference. the only thing I have going for me is that I won't have a tail wind. headwind sometimes but never a tailwind.
-- Knight-Toolworks & Custom Planes Custom made wooden planes at reasonable prices See http://www.knight-toolworks.com For prices and ordering instructions.
<carlfogel@comcast.net> wrote in message> news:aqou51dfg7fhg3r2g3ee1n5b69den158ro@4ax.com...>>On Thu, 14 Apr 2005 23:30:12 -0700, "Magnusfarce">><magnusfarce@adelphia.net> wrote:>>And there's the obvious www.mrtuffy.com, but it seems to be>>having internet hiccups.
Ken wrote:> Yeah the site seems to be having some sort of a break down. Do they make> them for older sized tires? i.e. 26x1&3/8?
Rimliners are sold by width . Either overlap or cut for various diameters
