• 08-30-2005
    Fixed
    what's best on rough chip seal?
    Man, they just love chip seal (small rocks thrown on top of existing pavement, which stick to it and feels sort of like large, rough, exposed aggregate) around here. Close to my house, there is a road they repaved with beautiful new, very smooth, asphalt 2 years ago (great for time trials), then this summer they came and destroyed it with a layer of rough chip seal. I don't get it. They left (sporadically) some smooth asphalt exposed on the shoulder/bike lane in places. I can tell it's noticeable faster, a good 1 mph, to be on the smooth versus the chip.

    Anyway, it got me thinking about what tire/pressure combo works best on chip seal (like for time trial speed)? Anyone experiment much with this? Seems to me that high pressure, narrow tires are not the way to go, as the bike seems to bounce and vibrate all to hell on this stuff. However, it's very hard to quantify this feel, and it may very well be that narrow (for aero sake) tires and high pressures are still faster, despite the feel. What do you all think?

    Thanks.
  • 08-30-2005
    Juanmoretime
    Me thinks you answered your own question.
    All I ride are chip and seal roads. I use Michelin Pro Race and Veloflex Paves with 110 PSI. The Pro are 23mm and the Paves 22mm. I'm only 155 lbs. The heavier guys around here ride 25's and low pressure.

    Quote:

    Originally Posted by Fixed
    Man, they just love chip seal (small rocks thrown on top of existing pavement, which stick to it and feels sort of like large, rough, exposed aggregate) around here. Close to my house, there is a road they repaved with beautiful new, very smooth, asphalt 2 years ago (great for time trials), then this summer they came and destroyed it with a layer of rough chip seal. I don't get it. They left (sporadically) some smooth asphalt exposed on the shoulder/bike lane in places. I can tell it's noticeable faster, a good 1 mph, to be on the smooth versus the chip.

    Anyway, it got me thinking about what tire/pressure combo works best on chip seal (like for time trial speed)? Anyone experiment much with this? Seems to me that high pressure, narrow tires are not the way to go, as the bike seems to bounce and vibrate all to hell on this stuff. However, it's very hard to quantify this feel, and it may very well be that narrow (for aero sake) tires and high pressures are still faster, despite the feel. What do you all think?

    Thanks.

  • 08-30-2005
    biknben
    I deal with chip-seal often. I too notice it is much faster when riding on smooth asphalt. To counter the chip-seal, I train on 25c tires with standard wheels. I think comfort has as much to do with it as anything else. When I'm more comfortable in the saddle, I am able to concentrate on applying more force to the pedals and go faster.

    I might be able to go as fast with a different setup but I'd be more uncomfortable. That comfort distraction would keep me from riding as fast as I could.

    Going Off-Topic:
    Can anyone offer an explanation why they would choose Chip-Seal over Asphalt? Chip-Seal method is an obvious money saver initially but has a much shorter life-span. In my area, where it snows, I would expect the life-span to be really low. I suspect the chip-seal would also eat snow plow blades and cause great expense there. Does it really cost less in the long term?
  • 08-30-2005
    Allez Rouge
    Quote:

    Originally Posted by biknben
    Does it really cost less in the long term?

    Possibly not, but as we all know, The Big Picture rarely has anything to do with how a government body spends money. Usually they'll have $X to work with during a given fiscal period and have to find ways to spread it around as best they can, to do the most overall good, "for now." And then not worry about what do do when the problem resurfaces (no pun intended) until that actually happens.

    In a snowy clime, where the roadways are subject to frost heaves, chip seal may well be the most economical. It would make little sense to spend big dollars on a real paving job if the first winter is just going to tear it up.
  • 08-30-2005
    bikejr
    Quote:

    Originally Posted by biknben
    Going Off-Topic:
    Can anyone offer an explanation why they would choose Chip-Seal over Asphalt? Chip-Seal method is an obvious money saver initially but has a much shorter life-span. In my area, where it snows, I would expect the life-span to be really low. I suspect the chip-seal would also eat snow plow blades and cause great expense there. Does it really cost less in the long term?

    http://www.wsdot.wa.gov/regions/East...esurfacing.cfm

    I suspect the biggie..

    <!--StartFragment -->The cost of chip seals is 15%-20% of the cost of pavement overlays.

    I suspect the government doesn't look much beyond that statistic. I.E. long term/secondary disadvantages etc...
  • 08-30-2005
    CNY rider
    Not sure when that data is from but remember that smooth shimmering blacktop is a petroleum product, and the price is likely going up exponentially as are prices for all other petro....
  • 08-30-2005
    TWD
    Quote:

    Originally Posted by biknben

    Can anyone offer an explanation why they would choose Chip-Seal over Asphalt? Chip-Seal method is an obvious money saver initially but has a much shorter life-span. In my area, where it snows, I would expect the life-span to be really low. I suspect the chip-seal would also eat snow plow blades and cause great expense there. Does it really cost less in the long term?

    As mentioned in another reply, cheap seal is a lot cheaper to apply than an asphalt overlay. Chip seal is used to seal off cracks in the pavement to extend the life of the roadway. Sealing off the cracks keeps water from seeping in then expanding when it freezes, which spreads the cracks and tears up the pavement.

    It makes sense from a long term standpoint in that it is cheaper to seal the road every few years than it is to either let it go and have to tear out all of the asphalt and start over, or to put down a more expensive asphalt overlay every time the cracks re-appear.

    What really drives me nuts is the size of the aggregate that they use. When I lived in the midwest, the aggreage was "pea-gravel" sized, and once it finally got worked in to where there was no more loose gravel on the road, it really wasn't that bad to ride on.

    Where I live now in Oregon, they use really coarse aggregate. It creates a heck of a lot of road noise in your car, and is brutal to ride on.

    On the other hand, it drastically reduces road spray in the wet, so visibility is much better when it's raining while driving in the car, and you don't get as wet from road spray while riding. Wet traction is also better than smooth asphalt.

    I've come to embrace chip-seal in the winter, and curse it in the summer.

    And in reply to the OPs question, it's my opinion that lower pressure is going to be faster. I'd rather have my tires conforming to the road rather than bouncing over it transmitting the vibration through the bike and to me.

    From many years of riding/racing mtb and cyclocross, it's been my experience that running tire pressure too high on rough surfaces really slows your momentum since you bounce up and over ever little obstacle rather than having your tires conform to obstacles and roll over. I notice the same effect with 26 x 2.3" mtb knobbies, 700x35 cross knobbies, and 700x23 road tires.

    If nothing else, that smooth feeling of floating over the rough stuff, is a placebo that helps me ride faster since I'm concentrating on putting power to the pedals rather than getting beat up by my bike.
  • 08-30-2005
    Dr. Crash
    riding on chip-seal no problem....
    ...crashing is. Man does it suck.

    Give me that smooth smooth petro based asphalt to skid across instead. Much better.
  • 08-31-2005
    colker1
    steel bike and fork, turbo saddle, 23mm tires at 100 psi, 150 lbs carcass... i can live w/ it.
  • 09-07-2005
    Ducatiman
    In addition to the chip seal, I have to live with cracks that will dislocate the fillings in your teeth. Last year, I built up a Litespeed Vortex to try and deal with the ride. It turned into a weight weenie project with Zipp 40mm carbon tubular rims and 19mm Tufo Lites at 120 psi. I was proud of myself for coming in at 14.5 lbs and dealing with the tubular issues i.e. gluing and all that stuff. But the ride sucked!! I went to Velomax Ascent II clinchers with 23mm tires and still 120psi. That helped but at 800 miles, I sold the Vortex and went back to my Kestrel 500Sci (can you say carbon fiber 100 times) Velocity Deep V, Michelin Pro Race, 120psi. I believe the answer to bad surfaces is carbon fiber, carbon fiber, carbon fiber and at least 23mm tires and probly as many spokes as you can live with. Just my 2 cents...
  • 09-07-2005
    filtersweep
    Quote:

    Originally Posted by Ducatiman
    In addition to the chip seal, I have to live with cracks that will dislocate the fillings in your teeth.

    It is funny how whenever my inlaws from Norway visit, they always ask "what's that noise" when I pick them up from the airport... the ka-chunk...ka chunk... ka-chunk as the car drives over the concrete expansion joints that have been paved over with asphalt. I swear the US has the worst roads in the industrialized world. We are penny wise and dollar stupid.
  • 09-07-2005
    Fixed
    been there
    Quote:

    Originally Posted by Ducatiman
    In addition to the chip seal, I have to live with cracks that will dislocate the fillings in your teeth. Last year, I built up a Litespeed Vortex to try and deal with the ride. It turned into a weight weenie project with Zipp 40mm carbon tubular rims and 19mm Tufo Lites at 120 psi. I was proud of myself for coming in at 14.5 lbs and dealing with the tubular issues i.e. gluing and all that stuff. But the ride sucked!! I went to Velomax Ascent II clinchers with 23mm tires and still 120psi. That helped but at 800 miles, I sold the Vortex and went back to my Kestrel 500Sci (can you say carbon fiber 100 times) Velocity Deep V, Michelin Pro Race, 120psi. I believe the answer to bad surfaces is carbon fiber, carbon fiber, carbon fiber and at least 23mm tires and probly as many spokes as you can live with. Just my 2 cents...

    Agree. More and more, I'm coming to the conclusion that a good bike is more about how it makes you feel at 12 mph on a rough pavement gentle climb, when you're bonked and 180 miles into a double, rather than whether it helps you go 40 instead of 38 mph on a descent. I used to do 200 mile solo rides across the California central valley, and there is plenty of chip seal and nasty ridges and cracks in a large section of the highway shoulder that would darn near knock parts off the bike. While the Cervelo P3 with Zipp disk, 404, and high pressure Tufos felt fast at first, it really wore me out 8 hours into the ride. My C40 with 120 psi Veloflex tires felt almost like a Cadillac in comparison.
  • 09-07-2005
    Kerry Irons
    Changing the right things?
    Quote:

    Originally Posted by Ducatiman
    Litespeed Vortex with Zipp 40mm carbon tubular rims and 19mm Tufo Lites at 120 psi. But the ride sucked!! I went to Velomax Ascent II clinchers with 23mm tires and still 120psi. That helped but at 800 miles, I sold the Vortex and went back to my Kestrel 500Sci (can you say carbon fiber 100 times) Velocity Deep V, Michelin Pro Race, 120psi. I believe the answer to bad surfaces is carbon fiber, carbon fiber, carbon fiber and at least 23mm tires and probly as many spokes as you can live with. Just my 2 cents...

    You blame the frame, but you use stiff wheels (deep section rims) and tires pumped quite hard. The best balance of ride comes from tires pumped to around 100 psi and wide enough to prevent pinch flats. CF frames, regardless of the manufacturer, will not have nearly as much impact as the wheels and particularly lower pressure in the tires.
  • 09-07-2005
    Mark McM
    Quote:

    Originally Posted by Kerry Irons
    You blame the frame, but you use stiff wheels (deep section rims) and tires pumped quite hard. The best balance of ride comes from tires pumped to around 100 psi and wide enough to prevent pinch flats. CF frames, regardless of the manufacturer, will not have nearly as much impact as the wheels and particularly lower pressure in the tires.

    I second Kerry's suggestion on tire width and pressure having a bigger affect on ride compliance than the frame. As can be seen in this test of vertical compliance of several bikes, the frame has the least compliance of all the components in the load path. Even if a frame had twice the compliance as any frame in this test, it would still be less than any of the other components, and a small fraction of the total compliance:

    Bicycle component vertical compliance

    As can be seen in the numbers, the tires have about 50 times the amount of vertical compliance as the frame. Keep in mind that this test was performanced on a perfectly smooth surface. Tires have the ability to conform to surface irregularities, so on rough surfaces the tires provide and even larger portion of the total compliance. Here's a quick and dirty test anyone can do: Deflate your rear tire completely, and ride down a rough road. Feel the difference in compliance between front and rear? That should tell you the amount of compliance the tire provides (and how little the rest of the components provide).

    However, I have to disagree slightly with Kerry's comment about "stiff wheels (deep section rims)". As can be seen in the website above, the wheels (apart from the tires) provide very little compliance - not much more than the frame does. The differences in compliance between one wheel and another don't amount to much in the total compliance picture. In fact, many wheels with deep section rims are _more_ compliant than wheels with shallow rims. Why? Because wheel vertical compliance usually depends more on the spokes than the rim. Wheels with many thick spokes and a shallow light rim can be vertically stiffer than a wheels with few spokes and deep heavy rims. Keep in mind that wheel can not flex vertically unless the spokes flex, and a single spoke has a stiffness between 5,000 and 10,000 lb/in (depending on thickness) - A wheel with a whole set of spokes will be stiffer still. Here is another test showing this affect:

    Grignon wheel test
  • 09-07-2005
    Fixed
    geometry, too
    Quote:

    Originally Posted by Mark McM
    I second Kerry's suggestion on tire width and pressure having a bigger affect on ride compliance than the frame. As can be seen in this test of vertical compliance of several bikes, the frame has the least compliance of all the components in the load path. Even if a frame had twice the compliance as any frame in this test, it would still be less than any of the other components, and a small fraction of the total compliance:

    Bicycle component vertical compliance

    As can be seen in the numbers, the tires have about 50 times the amount of vertical compliance as the frame. Keep in mind that this test was performanced on a perfectly smooth surface. Tires have the ability to conform to surface irregularities, so on rough surfaces the tires provide and even larger portion of the total compliance. Here's a quick and dirty test anyone can do: Deflate your rear tire completely, and ride down a rough road. Feel the difference in compliance between front and rear? That should tell you the amount of compliance the tire provides (and how little the rest of the components provide).

    However, I have to disagree slightly with Kerry's comment about "stiff wheels (deep section rims)". As can be seen in the website above, the wheels (apart from the tires) provide very little compliance - not much more than the frame does. The differences in compliance between one wheel and another don't amount to much in the total compliance picture. In fact, many wheels with deep section rims are _more_ compliant than wheels with shallow rims. Why? Because wheel vertical compliance usually depends more on the spokes than the rim. Wheels with many thick spokes and a shallow light rim can be vertically stiffer than a wheels with few spokes and deep heavy rims. Keep in mind that wheel can not flex vertically unless the spokes flex, and a single spoke has a stiffness between 5,000 and 10,000 lb/in (depending on thickness) - A wheel with a whole set of spokes will be stiffer still. Here is another test showing this affect:

    Grignon wheel test

    It's been my experience that a dedicated time trial bike, moving a lot of weight to your arms and shoulders, beats you up a lot worse than a relaxed angle bike. A more traditional angle bike seems to allow you to put more weight on your feet when you hit bumps, instead of having the bump forces slamming into your arms and butt. Nonetheless, I do think that some frame materials, like carbon, damp vibration better than others. (I have a real hard-on for a new Cervelo P3 carbon...)

    Agree on the wheels, too. While I've seen rims flex a whole lot laterally, when cornering or standing, (my Lew rim Velomax Ascent Pros are horrible), I can't discern any vertical compliance. Tires can make a huge difference, though. My 25 mm Continental Comps tubulars feel dramatically different than my stiff as iron Tufo 19 mm tires.
  • 09-07-2005
    ToneB
    riding on chip-seal
    I ride quite a bit on chip sealed roads here in the S.F. Bay Area. I have ridden on plenty of different rims and almost exclusively one tire type. The rims make a slight difference going straight down a chip sealed road (cornering/climbing is the biggest advantage with HQ rims). I am 175lbs and ride on 23mm Continental Grand Prix at 115psi. The front tire keeps a stiff profile and wants to bounce over obstacles but on chip seal it handles it well. The rear tire at that pressure is perfect for me for climbing/sprinting/long distance riding.
    At the time of buying my bike I was lucky in that the store behind me had a residential street that was recently chip sealed and this made my decision on which bike to buy very quickly. I test drove the Trek 5200 CF frame ('01 vintage). On the chip seal it vibrated like a dremel tool in my hands. On the Klein Quantum (with a CF fork) it rode like a normal bike, no vibration at all. Both bikes had the same rims, same tires and pressure. The CF picks up the high freq vibration fm chip seal and transmits thru the frame, maybe other CF bikes are not like this. But the Klein was more like a steel framed bike in that it behaved like one on chip seal which is about 70+% of what I ride on.
    Ride safe... Tony
  • 09-07-2005
    BenR
    that's interesting...
    Quote:

    Originally Posted by ToneB
    I ride quite a bit on chip sealed roads here in the S.F. Bay Area. I have ridden on plenty of different rims and almost exclusively one tire type. The rims make a slight difference going straight down a chip sealed road (cornering/climbing is the biggest advantage with HQ rims). I am 175lbs and ride on 23mm Continental Grand Prix at 115psi. The front tire keeps a stiff profile and wants to bounce over obstacles but on chip seal it handles it well. The rear tire at that pressure is perfect for me for climbing/sprinting/long distance riding.
    At the time of buying my bike I was lucky in that the store behind me had a residential street that was recently chip sealed and this made my decision on which bike to buy very quickly. I test drove the Trek 5200 CF frame ('01 vintage). On the chip seal it vibrated like a dremel tool in my hands. On the Klein Quantum (with a CF fork) it rode like a normal bike, no vibration at all. Both bikes had the same rims, same tires and pressure. The CF picks up the high freq vibration fm chip seal and transmits thru the frame, maybe other CF bikes are not like this. But the Klein was more like a steel framed bike in that it behaved like one on chip seal which is about 70+% of what I ride on.
    Ride safe... Tony

    I had the opposite opinion about both bikes, but also had a strong preference for the Klein. I had the same parts,wheels and Icon fork on both frames. My '99 Trek 5200 was a fine race frame (stiff, light, quick enough) but was boring to ride. I thought it muted many of the vibrations such as chip seal, but anytime I hit a solid bump like RR tracks, expansion joints, etc. I'd be jarred to the reality that it is still a very stiff frame. Then I got a '99 Quantum (fit me better). I love the ride and it is still my main bike. It has more of the buzz that fat tube aluminum is known for, but it seems tuned in such a way that it isn't harsh. Chipseal is obvious enough to get an idea of how hard you can push it in a corner, but it isn't what I would call harsh, although tires make a huge difference. I also thought it handled really hard bumps (like expansion joints) more softly than the Trek while still being torsionally stiffer. I have used & hated other aluminum frames like a caad 3 and an early 90's Raleigh, so please understand I'm not the occasional freak that enjoys the vibrations. That said, I race a lot and don't usually ride more than 65 miles on a typical weekend ride. If I was 50 something and doing double centuries, I'd probably swear by my Bridgestone or Waterford with Veloflex sew ups. For now, I have yet to find a frame that is this stiff with the same kind of ride quality (haven't ridden the top stuff though, since Pinarellos and such are out of my budget). I HAVE ridden some of the newest top race bikes (some more extensively than others) including: Specialized E5 (NOT the Tarmac), CAAD7, most recent carbon Giant, standard '04 Trek Madone, and top end BMC road frameset. Someone would still have to pay me to get off the Klein. The only exception might be Principia. I rode an older Rex Pro around the parking lot and was impressed, but I'm also not sure it's worth paying $2500 for an overglorified soda can. I don't know if the newer Kleins are the same way, but I'll be pretty biased when it comes time to shop for a new bike.
  • 09-07-2005
    bsdc
    I ride 28c at 80 psi on some very rough roads near me. It makes for a very comfortable ride. I use 23c at 110psi on fast smooth rides.
  • 09-08-2005
    Matno
    My experience: Tires make a difference, but a frame CAN make a huge difference. I had an old (~1990) Schwinn SuperSport Columbus steel frame that was bone jarring on any surface. (I always rode 28c Contis with 90-100psi). Rode a buddy's CAAD4 and was blown away by the smoothness. Decided I had to smooth my ride. Started with the wheels - barely noticeable improvement. Then the stem - nope. Finally decided to bite the bullet and got a CAAD4 frame. But I kept the same wheels and had the same tires all the way through from the beginning. (I rode those tires for YEARS. They were bombproof. Finally ditched them after riding the C'dale for a couple months. The sidewalls were beginning to crumble and the clearance on the fork was a little too tight for road debris).

    Difference? HUGE. I'm a lightweight rider (135-140), but anyone who says that C'dale frames are too stiff for light riders should try riding my old Schwinn! The Cannondale is SO much smoother. Even after I switched to 23c tires, it's still at least 100x better at separating me from road vibration.

    Purely subjective, but I was REALLY trying hard to compare the two and was not expecting nearly as much difference as I found. Maybe the carbon fork vs steel fork had something to do with it? Or maybe my Schwinn was just "tuned" to vibrate. I could hold the saddle in my hand and bounce the back wheel on the ground, and it would continue to vibrate for over 30 seconds! OUCH!
  • 09-09-2005
    Bryan
    I run 25c at 120psi. It really hasn't made my ride anymore comfortable, but I haven't had a single pinch flat since I've gone this route. Probably 95% of my riding is done on chip seal. It's amazing the difference you feel when you go from chipseal to asphalt. It's like switching from Govt issued Mil-Spec toilet paper to Double Quilted Charmen.