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  1. #1
    Si Senior dbg's Avatar
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    smooth road worth 3 MPH

    Just back from the annual WI trip.. We noticed that transitioning from a somewhat choppy (expansion joints, patches, etc) pavement to a fresh smooth pavement would increase our speed at least 3 mph, and more if we were in an aggressive pace line. I think this will increase my inclination toward larger tires on my light touring build (up to 700x32 or 35). Smoothing out the small but harsh bumps does seem to increase speed/efficiency. One of the other riders is leaning toward even bigger tires. (I was riding a Lemond BA with 700x25 this year.)
    David Green, Naperville, IL USA "The older I get, the better I used to be" --Lee Trevino

  2. #2
    Have bike, will travel Barrettscv's Avatar
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    I also see a real loss of speed on broken pavement with smaller road bike tires. Broken concrete is the worse and I'll lose 2 or 3 mph compared to perfectly smooth asphalt.

    I'm running a very supple Randonneuring tire on my Cyclocross bikes in either a 700x32 or 700x38 size. The Vittoria Randonneur Hyper is built like a high end road tire with a 120 tpi casing, a supple tread compound and light weight construction. I can use these on bad roads and on dry & firm trails with no loss in rolling resistance compared to very smooth pavement. The ride quality is float-on-cloud smooth.

    The added size is a factor at higher speeds (above 20 mph) and the small amount of added weight might slow a climb by a few seconds. But the fear-no-surface confidence that a larger tire provides is worth a very small trade-off in top speed or climbing.

    I'm also using 700x40 Schwalbe Marathon Durumes on one bike. The tire is super secure on wet or slightly soft surfaces. However, it's overkill on pavement. Great tire for mixed trails and pavement in all weather, but not as fast as the Randonneuring tire.
    Last edited by Barrettscv; 08-08-12 at 07:24 AM.
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  3. #3
    Senior Member TomD77's Avatar
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    I've got a fairly definitive test of just how much kinetic energy is wasted in vibration on very rough surfaces and 25mm tires inflated to over 100 psi.

    A stretch that I ride often was repaved recently. Before the new paving this rural 3 mile portion was the roughest I had ridden anywhere, any speed greater than around 14 mph would literally blur my vision if I was on the seat.

    At one part of the ride on this road, a 150 foot hill crests and there is a several hundred yard downhill portion at 1.75% (per my Garmin). I usually work the little hill fairly hard and just take the short downhill without pedaling as a quick recovery. Before the new paving I would coast down the back side at a rough and vibrating 12 mph, max, no wind. The exact same coast down with the smooth new paving is almost exactly 17 mph. Therefore, the energy equivalent of a full 5 mph was being used to vibrate the system (Me). But this road was a special case; in addition to being constructed of tar and large gravel, it was wash boarded to boot.

    For any locals, this was Whiting Field Circle behind the Navy base.

  4. #4
    Semper Fi, A way of life. qcpmsame's Avatar
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    You are actually being kind to call that stretch of road rough, Tom. A mine field comes to mind when I think of Whiting Circle.

    Bill
    "I Can Do All Things Through Christ Who Strengthens Me" Philippians 4:13

  5. #5
    Senior Member Garfield Cat's Avatar
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    This velonews article may be interesting. It discusses each of the teams' choice of wheels and tires on the Paris Roubaix.

    http://velonews.competitor.com/2012/...running_212925

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    I've noticed faster speed, (yep, maybe 2 to 3 mph) on new, smooth pavement also. I also use 28mm tires because that is all that will fit on my bike. My original motivation for 28mm tires was to soften the ride due to a bad back. I weigh 165 pounds currently and pump up tires to 65-70 F and 85 R psi. This has been fine pressure for 7000 miles over smooth or older and rough back roads. An extra bonus has been, as Barrett has said, a versatile tire on varied surfaces. I don't worry about a bit of sand or gravel on the road.

  7. #7
    Senior Member MinnMan's Avatar
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    I would have guessed more like 1-2 MPH, but I have no quantitative data to back up that claim. But regardless of the numbers, there's nothing like a smooth road surface to increase my enjoyment. This month I've been riding in Santa Barbara, where pretty much all the roads are gorgeous smooth asphalt (hot mix). Last year i was riding in Canberra, which otherwise has great riding, but all the roads are REALLY coarse chipseal. Awful road buzz. And normally I ride in pot-hole ridden Minnesota.

  8. #8
    Senior Member GeorgeBMac's Avatar
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    Quote Originally Posted by Garfield Cat View Post
    This velonews article may be interesting. It discusses each of the teams' choice of wheels and tires on the Paris Roubaix.

    http://velonews.competitor.com/2012/...running_212925
    Thanks for the article -- that was interesting... What interested me the most were the low tire pressures: My 700x28's have recommended pressures of 110-120 psi. The pros discussed in that article were using similar sized tires but far lower pressures...

    I've heard a number of times that a lower pressure can make for a better ride. But, when I'm 10 - 15 miles from my car I don't especially want to deal with a flat -- so I've been keeping the tires at the presures the manufacturer recommends and bounce my way along...

    Maybe I need to rethink that...
    --------------------------------------
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  9. #9
    Senior Member bruce19's Avatar
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    I run 700x23's on my Masi Gran Criterium. Last year I was doing my 15 mi. TT and trying to hit a PB of over 17.4 mph. At about 2 mi. from home and on track to succeed I crested a hill on the fastest part of the route. Just as I was headed down a nice long stretch the road turned to fresh chip seal. I mean fresh like put down yesterday and the bike went all sideways and stuff. Didn't go down but that sure as hell killed my PB and the ride in general. This year I had to create a different TT route. That piece of road still sucks a year later.

  10. #10
    Have bike, will travel Barrettscv's Avatar
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    Tip 1 - Inflate your tires before every single ride. Know what the proper inflation pressure should be for your tires. Inflation requirements will vary by rider, bike, tires, conditions, etc.

    read: http://www.bikequarterly.com/images/TireDrop.pdf


    Proper inflation is the easiet way to avoid flats.

    Use this online calculator to adjust air pressure for both rider weight and tire size: http://www.dorkypantsr.us/bike-tire-...alculator.html

    Adjust from these baselines to suit needs and conditions.
    2014 Trek DS.1: "Viaggiatore" A do-it-all bike that is waiting in Italy
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    2010 Origin 8 CX 700: "Servizio Grave" Monstercross/29er bike
    1997 Simoncini Special Cyclocross: "Little Simon" lugged Columbus steel CX bike
    1987 Serotta Nova Special X: "Azzurri" The retro Columbus SPX steel road bike

  11. #11
    Semper Fi, A way of life. qcpmsame's Avatar
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    I found a new section of road to add to my rides. It is like riding what I imagine the cobbles is supposed to be. The surface is a much larger aggregate size than the roads normally have around our area. I set my tyre pressures at 110 every ride, using 700x23 Schwalbe Luganos, and this section was a real eye opener for me. (Literally) My bike has minimal clearance as the 23's are tight in the fork and stays. I think I could run a 25 if the tire profile is right but I doubt I can fit a 28 in the space provided. I am strongly considering a set of 25's next, first I will drop the tyre pressure to around 90-95 psi on days I ride this road. Good link to the VeloNews article.

    Bill
    "I Can Do All Things Through Christ Who Strengthens Me" Philippians 4:13

  12. #12
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    Interesting timing. Just yesterday I mounted a pair of 700x28 Challenge Parigi-Roubaix tires, replacing Challenge 23's. First, the install was as difficult as I've ever experienced, even broke one plastic Park Tools lever. I'd been running the 23's at near max pressure at the rear and about 30 psi less at the front. On smooth pavement the ride was fine, but if not perfect pavement the vibration was very apparent.

    I inflated the new tires at the front to 75 psi, rear 115 psi per the link above (225 svelte lbs for rider and 22 for bike). First test ride, 7 laps of a 1.25 loop at the office was very smooth, and despite three stops to reposition the magnet on the rear wheel, moved as a result of the installation struggle, my average speed was above normal for this loop, and the max speed recorded on a rough false flat was 2 mph greater than all other rides on the same loop. I'm headed out for 22 miles with mixed pavement, flats and hills later today which will be a far more valuable test, but initial results are encouraging.

  13. #13
    just keep riding BluesDawg's Avatar
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    Quote Originally Posted by GeorgeBMac View Post
    Thanks for the article -- that was interesting... What interested me the most were the low tire pressures: My 700x28's have recommended pressures of 110-120 psi. The pros discussed in that article were using similar sized tires but far lower pressures...

    I've heard a number of times that a lower pressure can make for a better ride. But, when I'm 10 - 15 miles from my car I don't especially want to deal with a flat -- so I've been keeping the tires at the presures the manufacturer recommends and bounce my way along...

    Maybe I need to rethink that...
    110-120 psi in 28mm tires seems extreme unless you are a very heavy rider. At 170 lbs. myself, I run maybe 70 front and 80 rear with 28s, often less. Tires usually show maximum suggested pressure. You don't have to go that high, just high enough to avoid pinch flats.

    Re: the low pressures the pros run at PR, they are riding tubulars, so there is no tube and pinch flats are not a concern.
    The more you ride your bike, the less your ass will hurt.

  14. #14
    Senior Member GeorgeBMac's Avatar
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    Quote Originally Posted by BluesDawg View Post
    110-120 psi in 28mm tires seems extreme unless you are a very heavy rider. At 170 lbs. myself, I run maybe 70 front and 80 rear with 28s, often less. Tires usually show maximum suggested pressure. You don't have to go that high, just high enough to avoid pinch flats.

    Re: the low pressures the pros run at PR, they are riding tubulars, so there is no tube and pinch flats are not a concern.
    Thanks for the tip... My butt will thank you!
    --------------------------------------
    bikes: 1992 Cannondale R500, 2012 Trek DS 8.5, 2008 LeMond Poprad

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