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  1. #1
    just another gosling Carbonfiberboy's Avatar
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    More fun with tires

    I've been of the narrow high pressure tire persuasion, using Vredestein Fortezza Tricomp 23c at 140 lbs. This has worked very well for us riding our hometown, rather rural and low traffic roads. However, our tandeming world is expanding, as we've started leading group tandem rides near a neighboring metropolis. The roads there are much higher traffic and are littered with glass and other nasty objects. Perhaps the street sweeping budget isn't what it was. In any case, this past Sunday we had the Captain's Nightmare - our front tire sustained a serious puncture just before a righthander at the bottom of a fast descent.

    Luckily I've been reading posts on this forum for a while, and practice my reaction series every time we ride: get on the other brake, assess oncoming traffic, assess traffic behind, and make a decision, assuming there's time for all that. We had no oncoming (yay!) and we went just a bit over the centerline before getting it back under control and stopping on our shoulder. Rim was OK.

    We could try TG's suggestion and go to the plain Vredestein Fortezza, but my riding buddies vetoed. So I purchased a variety of single tires to test for rolling resistance and then ride. I only purchased tires with a good reputation for adhesion in the wet, good flat resistance, and yet some claim for low rolling resistance and good handling. I tested RR by putting the trial rear tire on my rollers and clamping the front end in a jig, then riding from the stoker position, so only the rear tire was rolling. I rode each tire at a 105 HR (no power meter) until I got a steady speed reading, 3-5 minutes. The differences in leg loading were obvious. I ran the series twice, testing each tire twice. Results, averaged:

    Tire-------------------------Size----Pressure---Speed
    Vredestein Tricomp-------23c-------140---------18.1
    Conti 4000, black chili-----25c-------120---------17.9
    Vittoria Rubino Pro Tech--28c-------120---------16.8
    Schwalbe Durano----------25c-------115---------17.0
    Maxxix Re-Fuse------------25c-------120---------15.9

    Looks like the greater the putative flat resistance, the slower the tire, just what one would suspect. We now have the Conti 4000 on the back and the Durano on the front. We'll run each tire in turn on the back until it's worn out. We've already tried it with the 4000 on the back and a Vredestein on the front. Those different tires didn't seem to matter to handling. We'll see how it goes.

  2. #2
    Senior Member swc7916's Avatar
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    I didn't see any tandem group rides for last Sunday on the Evergreen Tandem Club website, so what group are you riding with?

    We were in Everett Sunday due to a harebrained idea of mine that we should ride the Lowell Snohomish River road from Snohomish to Everett, then go south on the Interurban trail. That climb from Lowell Park to Broadway gained 200' in less than 1/2 mile! If we even do that again it will be in the other direction.
    Last edited by swc7916; 04-20-10 at 03:00 PM.

  3. #3
    Senior Member zonatandem's Avatar
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    For the past few years we've been riding the Maxxis Re-Fuse 700x25s on front and rear of our tandem.
    We live in cactus country (southern Arizona) and more than normal flat opportunities; the Re-Fuse is a great tire for us.
    In the last 4,090 miles (on 2 rear tires) we had NO flats. Had one flat (leaky patch) on front tire.
    Almost tempted to quit carrying pump and spare tube!
    Pedal on TWOgether!
    Rudy and Kay/zonatandem

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    Senior Member mkane77g's Avatar
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    How about testing Michelin's. we get around 1100 miles on a rear, no flats. Very smooth riding tire. 110psi.

  5. #5
    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by swc7916 View Post
    I didn't see any tandem group rides for last Sunday on the Evergreen Tandem Club website, so what group are you riding with?

    We were in Everett Sunday due to a harebrained idea of mine that we should ride the Lowell Snohomish River road from Snohomish to Everett, then go south on the Interurban trail. That climb from Lowell Park to Broadway gained 200' in less than 1/2 mile! If we even do that again it will be in the other direction.
    It's just a group of people with whom I've been riding for years. As we've aged, some of us have eased off on the competitive riding thing and gone to having fun with our sweeties, which can still be competitive riding, but a with little more complex dynamic! We enjoy riding with folks whom we've known for years and whose riding is absolutely predictable and safe. I don't want to advertise, but my avatar is not random.

    Yes, that's a nice climb, isn't it? We do the bottom part of that almost every time we go out. Builds character.

  6. #6
    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by zonatandem View Post
    For the past few years we've been riding the Maxxis Re-Fuse 700x25s on front and rear of our tandem.
    We live in cactus country (southern Arizona) and more than normal flat opportunities; the Re-Fuse is a great tire for us.
    In the last 4,090 miles (on 2 rear tires) we had NO flats. Had one flat (leaky patch) on front tire.
    Almost tempted to quit carrying pump and spare tube!
    Pedal on TWOgether!
    Rudy and Kay/zonatandem
    I agree absolutely. That does look like a great tire. I'm looking forward to flat and wear testing all these tires. My testing method, due to using two 3" rollers instead of one earth, considerably overestimates the variation in rolling resistance, which of course is only a small part of a tandem bike's resistance. I appreciate your input, and am very tempted to put the Re-Fuse on the front and just leave it there, precious cargo and all that.

  7. #7
    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by mkane77g View Post
    How about testing Michelin's. we get around 1100 miles on a rear, no flats. Very smooth riding tire. 110psi.
    Yes, but which Michelins? I thought about the Krylions, but read posts that said the quality was bad since they moved their manufacture to Asia. So many tires, so little time.

    A side note to all: when I was done testing all these new tires, I had a thick strip of wax stuck to my rollers which I had to scrape off. So never take a new tire out on a wet day. Ride it 50 miles or so in the dry first.

  8. #8
    pan y agua merlinextraligh's Avatar
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    Interesting information, but a lot of confounders. Most notably would be heart rate drift.

    Also RR on real world roads, with the weight of 2 riders, would be different, than with the weight of only one on smooth rollers. There's data to indicate that higher pressures on regular roads with imperfections causes more rolling resistence.

    Another consideration, in addition to rolling resistence, is wind resistence. The wider tire, particularly on the front is going to be less aerodynamic. The Zipp rep told me that the difference between 23mm and 25 mm on a set of 808's is worth 7 watts.

    If you want to do more testing, you might try doing a roll down test with the various tires.
    You could fall off a cliff and die.
    You could get lost and die.
    You could hit a tree and die.
    OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.

  9. #9
    Senior Member mkane77g's Avatar
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    Michelin Krylion, 25mm. Very smooth riding tire, are now made in Asia. We have used these for many years, and when my supply runs out we will be switching brands, back to Conti's. Mabey give the 4000's a try.

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    I really like the GP4000 or GP4000s with the "black chili" compound. Really durable but pretty lightweight, corners great, smooth ride on a tandem (but not on my single!).
    I think they scored well on rolling resistance tests too.
    I use the GP4000S 23c on the front and GP4000 25c black on the rear.

  11. #11
    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by merlinextraligh View Post
    Interesting information, but a lot of confounders. Most notably would be heart rate drift.

    Also RR on real world roads, with the weight of 2 riders, would be different, than with the weight of only one on smooth rollers. There's data to indicate that higher pressures on regular roads with imperfections causes more rolling resistence.

    Another consideration, in addition to rolling resistence, is wind resistence. The wider tire, particularly on the front is going to be less aerodynamic. The Zipp rep told me that the difference between 23mm and 25 mm on a set of 808's is worth 7 watts.

    If you want to do more testing, you might try doing a roll down test with the various tires.
    Good points. We need every 7 watts we can find. So far the rear Conti 25 is showing no signs of wear, glass cuts, etc., not a mark on it. Very encouraging. Yes, a Conti 23 for the front might be the thing.

    I don't know the protocol for a roll-down test that would isolate rolling resistance. Anyone?

    HR drift is not an issue. I can maintain exactly the same speed at a 105 HR for at least an hour. That's the reason I chose that speed. Fluid temperature in the resistance unit is a bigger issue. And certainly real world will be different, but I don't think it would re-order the tires, just reduce the gaps between them. One of the reasons I chose this testing method is that I knew RR differences would be easier to measure this way than in the real world. I ran the second set in reverse order and got essentially the same speeds. The only real trick was to devise a restraint for the front that allowed the rear wheel to center itself between the two rollers.

    Haven't seen said rough road data, only speculations. Brandt doesn't think that's true, because real road imperfections are random, and thus don't create an energy absorbing oscillation. My experience in riding brevets on crappy road surfaces suggests that narrow HP tires are faster, but may create fatigue if the frame lacks vertical compliance. My descending speed vs. other riders does not seem affected by surface quality. And it's definitely not an issue on our CoMo.

    Most published RR tests are silly because they inflate all tires to the same pressure, instead of max recommended pressure. I used the sidewall pressure my testing, except for the Vredesteins, which I could have pumped up a lot more, but chose to test at the pressure at which I run them.

  12. #12
    pan y agua merlinextraligh's Avatar
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    Quote Originally Posted by Carbonfiberboy View Post
    .

    I don't know the protocol for a roll-down test that would isolate rolling resistance. Anyone?
    Mark a course with a decent hill, and no traffic. Start from a standstill. Measure elapsed time. Try to do it on a calm day. Also wear the exact same clothes, and try to maintain the same position as much as possible.

    You'll stil have wind gusts as a confounder. You'd need to run multiple heats for each tire, and alternate the order each heat to nuetralize that effect, which would make it a pretty big PITA chaning tires.
    You could fall off a cliff and die.
    You could get lost and die.
    You could hit a tree and die.
    OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.

  13. #13
    Senior Member mkane77g's Avatar
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    Were headed for Chico this weekend for our 19th consecutive 100 miler. If I can find some chili Conti's at a local bike shop I'll give em a try. We generally hammer this ride as we know the route so well, mabey these will contribute to riding time under 5 hrs.

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    Quote Originally Posted by mkane77g View Post
    Were headed for Chico this weekend for our 19th consecutive 100 miler. If I can find some chili Conti's at a local bike shop I'll give em a try. We generally hammer this ride as we know the route so well, mabey these will contribute to riding time under 5 hrs.
    They are usually pretty expensive at the LBS. I order mine from ProBikeKit. They are around $35 when they have them on sale which was recently.

  15. #15
    pan y agua merlinextraligh's Avatar
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    Quote Originally Posted by jnbrown View Post
    I really like the GP4000 or GP4000s with the "black chili" compound. Really durable but pretty lightweight, corners great, smooth ride on a tandem (but not on my single!).
    I think they scored well on rolling resistance tests too.
    I use the GP4000S 23c on the front and GP4000 25c black on the rear.
    We use GP 4000 as well. The "s" is only available in 23mm. However a black 4000 is the same as GP4000S. So if you want 25mm just get black ones, and it is the same black chili compound as the 4000S.


    As to how they score on rolling resistance, depends on what test you look at. Compare http://www.biketechreview.com/tires (click on the most recent Morrison PDF) to http://www.conti-online.com/generato...gp4000s_en.pdf

    Depending on who you believe the GP4000 (with black chili) has at least good rolling resistance, perhaps extremely good.
    You could fall off a cliff and die.
    You could get lost and die.
    You could hit a tree and die.
    OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.

  16. #16
    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by merlinextraligh View Post
    We use GP 4000 as well. The "s" is only available in 23mm. However a black 4000 is the same as GP4000S. So if you want 25mm just get black ones, and it is the same black chili compound as the 4000S.


    As to how they score on rolling resistance, depends on what test you look at. Compare http://www.biketechreview.com/tires (click on the most recent Morrison PDF) to http://www.conti-online.com/generato...gp4000s_en.pdf

    Depending on who you believe the GP4000 (with black chili) has at least good rolling resistance, perhaps extremely good.
    Thank you for your posts! I wish I'd seen the German TOUR magazine test earlier . . . But they didn't test the exact tires in which I was interested, anyway. Note that the Stelvio isn't made any more. The Durano is supposed to replace it, not the Ultremo. The Vredestein they tested is the tubular Pro version, not the Fortezza Tricomp I've been running, a very different tire, but yup, it does flat, though it's much better than the Pro and has a very good grip in the wet and dry, perhaps the best I've ever used.

    One of my pet peeves with the tire testers is that they test them all at the same pressure, even when a tire is specifically made to be run at a higher pressure - or maybe a lower pressure, though I don't know of an instance of that. But of course a tire will not perform to spec if it is run 25 lbs. lower than the pressure it is supposed to have. Vredestein and the Vittoria Open Corsa Evo CX are examples. These are thin, compliant tires that need high pressure to roll and corner.

    Morrison's tests are always well done, though again he runs them all at the same pressure. And I wonder if TOUR's problems with tubulars having higher rolling resistance is due to the same gluing problem that Morrison used to have and fixed. Morrison's bumpy tests confirm that higher pressure tires roll faster even on regular bumps.

    TOUR stops all the puncture tests at 180 seconds, yet we know that all these tires are not the same at repelling glass and goatheads, or where I live, blackberry thorns and radial tire wire. So there are flatting/resistance tradeoffs beyond what are shown in these tests. I have no doubt that Rudy and Kay would flat more often with Conti 4000.

    I am very curious about the rollers used by TOUR in their RR tests. Their wattage variations seem large. My variations are more in line with what Morrison is getting.

    And yup, everyone says the Pro2 tires are a pain to mount.

  17. #17
    Senior Member mkane77g's Avatar
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    Are all but the colored 4000's black chili's?

  18. #18
    Senior Member mkane77g's Avatar
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    According to Conti's website, yes the black versions have chili mixed in.

  19. #19
    hors category TandemGeek's Avatar
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    Quote Originally Posted by Carbonfiberboy View Post
    We could try TG's suggestion and go to the plain Vredestein Fortezza, but my riding buddies vetoed.
    I gotta ask...

    What was their rationale and/or past experience using Fortezza's on their tandems?

  20. #20
    just another gosling Carbonfiberboy's Avatar
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    Quote Originally Posted by TandemGeek View Post
    I gotta ask...

    What was their rationale and/or past experience using Fortezza's on their tandems?
    Nada. Rationality not required for bike riding. As you well know.

    They were in sight of us when I had my front flat, us in the lead. They were more scared for us than I was. I have to admit, that Durano on the front does feel pretty solid . . . We just have to find another 10 watts or so, not having the Vredesteins.

    I had a great workout this morning before breakfast and we had a good ride last night. The team is getting it together. 60 miles through the tulip fields on Sunday. Planning our first mountain pass ride on Memorial Day weekend. Stoker never thought she'd do that. The descent is technical on an unmaintained forest road, though not steep. My first time down it on a tandem. Slightly nervous.

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    hors category TandemGeek's Avatar
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    Quote Originally Posted by Carbonfiberboy View Post
    Nada. Rationality not required for bike riding. As you well know.
    FWIW, Vredestein Fortezza's are available in a 25mm version... not that they're as easy to find as they once were. Bike Tires Direct used to be my ready source for deeply discounted Vredestein Fortezzas, but they've been out of stock for quite some time now. What a pisser.

    Thankfully, I think I still have about 4 of the all-black 25mm Fortezzas, another 6 that have the natural / tan sidewalls and 2 or 3 of the 23mm SE's from Performance sitting on the shelf (all black, not the Smurf Edition SEs).

    Sadly, I haven't really had a bike where the natural sidewall models "look" quite right so they're well-seasoned, to say the least. I'm starting to formulate a plan that may allow me to make use of those suckers, but I may have to drink a lot of Tequila before pulling the trigger on the new project. Fortunately, the person I need to work out the details with is out of the country for a while so perhaps my recent bout with Irrational Exuberance will subside before they're available.
    Last edited by TandemGeek; 04-24-10 at 06:42 AM.

  22. #22
    just another gosling Carbonfiberboy's Avatar
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    Dark blue bike with polished VO fenders, black bottle cages, black bags and bar tape. Black tires look fine. Blue sidewall Vredesteins weren't right. Gray not so bad.

    Two friends ride a Jack Taylor with us. Those tan sidewalls would look fine. Bike is kind of a tan/off white color anyway. Though lately they've been bringing the Calfee, so maybe we're getting faster . . .

  23. #23
    Senior Member
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    @swc7916, next time go west from Snohomish on the north side of the river (Riverview, Riverside, Home Acres roads), west on Hewitt, south on Colby to the Interurban.

    Now, back to tires:
    The US importing office for Schwalbe is just up north of Bellingham. They were at the CBC Bike Expo and I talked with the guy some. The "Stelvio" name for bike tires is owned by someone and Schwalbe, after a fit of naming virtually every tire "Stelvio" (you had to look at the model numbers to know the difference), went to other names. There are now several Duranos, too. The Durano HS399 comes in both 23 and 25mm, and the 25 comes with a "reflex" - reflective - band, very good for low-light visibility if the other guys have headlights on. The Durano S HS 376 is supposed to be a new, improved Stelvio.
    You can maybe, maybe turn up some NOS tires by looking for European listings in Ebay. I was in need of a yellow/black older Stelvio, and found one in Britain.
    You might also try calling local bike shops and asking what they've got on hand. That funky store down in Lynnwood, west side of Hwy 99, with stuff hanging from the ceilings, had some of the original Avocet smooth tread / skinwall tires a few months ago when I stopped by.

  24. #24
    Senior Member mkane77g's Avatar
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    Chili Conti's mounted, they look like they might be a nice tire. Easy to mount on the Rolfs. Going to run 110lbs so I can compare them to the Michelin's as far as ride quality is concerned.

  25. #25
    Senior Member mkane77g's Avatar
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    At 110 psi the front seemed a bit low, especially when standing. When seated the it felt notchy, the tire seemed to have a real short contact patch, so I pumped them both to 120psi which cured the front end from hunting around. This made the ride a bit bouncy on the rough roads and I should have left the rear @ 110 psi to please the stoker. Next time I will adjust pressure according to road conditions. So far I am pleased with these tires. In May were headed for 8 day bike tour that averages 7000' of gain every day and will be a good test for these tires on the downhills.

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