Clydesdales/Athenas (200+ lb / 91+ kg) - higher tyre pressure = tougher ride?

hello,
i am 6ft 10ins,47 year old and about 330lbs..i cycle with several fit riders over very hilly terrain and we are too competitive at times..anyhows i have my specialised armadillos at 85 psi and have struggled and been lagging behind..feels like riding with the brakes on!..now 6 weeks after last pump tyres seem a littlr deflated and riding is easier...logic suggests higher psi = less tyre on the deck=less friction etc etc but, i am finding it easier ridng lower psi ...any thoughts?
BTW which part of your foot do you taller fellas use to pedal?..i have tried the ball,arch and now finding the heel gives me a little more drive..the ball stretches my leg muscles a lot at times..
cheers
mark
plymouth
uk

I the lower tire pressure may make for a smoother ride so you may feel more comfortable, but I can't believe it is easier. On my road bike I check my tire pressure regularly. I find the pressure goes down after a day or two. On my MTB the pressure doesn't decrease as fast, so maybe at 85 psi you aren't loosing much pressure. It seems odd that you feel like you are riding with the brakes on, I would say that is the low pressure, but then you say it is easier at even lower pressure humm. Maybe it is easier six week later, because you are in better shape.

I use the ball of my foot over the center of the pedal. I would suggest you check your fit. For starters with your riding shoes on put your heel on pedal and extend your leg. Then when you move to the ball of your foot you should have a slight bend. You should feel more power using the ball of your foot...maybe win a few of those sprints to the speed limit signs.

Hi,
I run 90 psi and need to top them up once every two - three days. If I am reading your post correctly, you need to check the air before you go out again. I think that if you run your tires at max psi for the tire, you tend to get less flats - could be an urban myth. I think it is correct to say that most folks use the ball of the foot. BTW - what bike do you have and the size?

The manufacturers started testing rolling resistance on steel drums a few decades ago. This may have been a big step backwards, as those tests showed that rolling resistance decreases with increased air pressure -- no exceptions. The problem is that the real world is not a smooth steel drum. It turns out that over real-world roads -- ie. ones with bumps -- narrow high pressure tires aren't always as fast as wider lower pressure tires, and that increasing pressure in those narrow tires can make them even slower. Essentially, it takes energy to bounce you and your bike around, and the more you and your bike are bouncing the more energy it takes. The bouncing you and your bike will do when riding, for instance, cobblestones on 19 mm clinchers at 180 PSI sucks up a surprising amount of energy, and if you've tried it, you'll know how much it slows you down. Try a pair of 28 mm tubulars with 90 PSI and you'll actually go faster -- and without nearly so much bouncing. Hmm...

I have no experience with Specialized Armadillos, and I have no idea what a bike feels like with 330 pounds aboard, but perhaps the above ideas may be useful for the OP.

hello,
i am 6ft 10ins,47 year old and about 330lbs..i cycle with several fit riders over very hilly terrain and we are too competitive at times..anyhows i have my specialised armadillos at 85 psi and have struggled and been lagging behind..feels like riding with the brakes on!..now 6 weeks after last pump tyres seem a littlr deflated and riding is easier...logic suggests higher psi = less tyre on the deck=less friction etc etc but, i am finding it easier ridng lower psi ...any thoughts?
BTW which part of your foot do you taller fellas use to pedal?..i have tried the ball,arch and now finding the heel gives me a little more drive..the ball stretches my leg muscles a lot at times..
cheers
mark
plymouth
uk

The general rule is that rolling resistance is reduced with higher pressure, the cost of that is a harsher ride. With an AL frame that harshness can be very tiring.

If you need to ride with the heel of your foot, either your saddle is not positioned correctly or the frame is the wrong size. A lot of riders with platform pedals do ride more on the arch then the by the proper position by the front of the foot (behind the toes), which is where clips or clipless pedals position your foot. This can also making riding more difficult. If you could post a picture of you riding, from the side, it would be easier to tell what the issue is.

optimum pressure for given tire width at given load per wheel (http://sooper-genius.blogspot.com/2007/06/optimum-tire-pressure-35mm-tires.html)

I pump up to 110 psi.

FWIW I'm 220 and ride 700x23 on my roadbike. For me the perfect setup is 120 on back and 110 on front. Bouncing around with 120psi may be an issue for a little guy but reality check, I ain't doing much bouncing at 220lbs. If your bike fits right you should have ball of foot on pedal or better yet try clipless.

FWIW I'm 220 and ride 700x23 on my roadbike. For me the perfect setup is 120 on back and 110 on front. Bouncing around with 120psi may be an issue for a little guy but reality check, I ain't doing much bouncing at 220lbs. If your bike fits right you should have ball of foot on pedal or better yet try clipless.

+1 almost exactly the same but 5 lbs heavier. Not too harsh and no pinch flats (which I used to get, but it depends on the road conditions you ride)

yup. 25 wide and at least 120psi. conti ultra gatorskins w/kevlar. durable, reasonable ride and grips well enough. theyre like fat black donuts around my rim.

i would run a 28 if i could, but the frame will only handle a 25.

im as gentle on wheels as a 100lb 14year old female junior, but id never, ever, ride under 100psi. i dont understand how some of you, us, clydes are running 85psi, or what i would consider a partial vacuum, without pinchflating getting on, your bike.

enjoy, spin classes are almost done for the year :) the women are pretty hot, though :(

i dont understand how some of you, us, clydes are running 85psi, or what i would consider a partial vacuum, without pinchflating getting on, your bike.

u also have to consider tire size, with the 23x700c's i have on my road bike, i run 125 psi... but on the hybrid i had a while back, i had 37x700c's at ~100psi, and sometimes i'd over inflate them to ~110psi...

also, most tires have a minimum pressure, run to close to that minimum pressure and add the weight of a clyde, and u can run the risk of pinchflats... in fact i think Sheldon Brown suggests over inflating based on total weight (rider, bike, and gear), but following the guide he created i should inflate my 23's to over 200 psi :twitchy:

Selected tire pressure should be a result of the load put upon a tire.

Maximum tire pressures, suggested by manufactures indirectly represent a "load maximum" as well.

If a tire deforms "excessively" during use while inflated to it maximum pressure, then the tire is being used beyond its suggested load capability.

However, most tires can be used beyond their "suggested" pressure/load capability. It is up to each cyclist to study the tire deformation, at both pressures, and determine if excessive pressure will lessen tire/wall deformation and thereby increase performance.

In many cases, over inflating a tire will not improve performance. For at least some tires it will.

Here in S E Michigan the roads are so bad I can't imagine trying to ride skinny rode bike tires !! I started out at 371 # on a cruiser 7 speed . Not to bad a ride considering the roads I have to deal with . Switched to a comfort bike with a front shock and 700x35 tires and its much better ! But ive lost a ton a weight . I run my tires at max + 5 pounds nary a problem . I am even running cheap tires price wise Kenda kouriers seem like awful good tires for the $$ but only a couple hundread miles on them so far . Max on my tires is 85 and I run them at 90 psi .

I am of the mindset that higher/lower pressure has no material effect on speed/resistance. There may be roll resistance factors at work, but not enough to feel on the average rider. It may provide a smoother/rougher feel for some rides. Lower pressure certainly does provide a tad more stability on wet roads however due to a slightly larger tire footprint. That said, I usually maintain between 100 - 110 psi. My tires are rated to 140psi, but I see no reason to go that high. I am 6'4" 237lbs. At my weight, I would however caution against having not enough tirep pressure, leaving me prone to punch flats, AKA snake bites. I would never ride below, say 90psi for that reason.

As for foot position on the pedals. Ball of the foot brings the more of the action of your entire leg into your pedal stroke. The more muscles you have "on deck", the less work load each has to bear-to draw an overly simple model. Imagine the the advantage in leg power a person swimming in flippers as opposed to a person swimming without them. The same is true with pedaling. With heels on the pedals, you use the upper leg, and eliminate the boot/ankle action.

After getting the balls of the feet on the pedals, I would focus on makinng perfectly round pedal strokes. I think of "unweighing" the foot at the top of the pedal and scraping the foot back on the bottom of the pedal stroke. Toe clips may help, and cleats are even better for efficiency. Efficiency means you can go faster and longer at the same energy level.

u also have to consider tire size, with the 23x700c's i have on my road bike, i run 125 psi... but on the hybrid i had a while back, i had 37x700c's at ~100psi, and sometimes i'd over inflate them to ~110psi...

also, most tires have a minimum pressure, run to close to that minimum pressure and add the weight of a clyde, and u can run the risk of pinchflats... in fact i think Sheldon Brown suggests over inflating based on total weight (rider, bike, and gear), but following the guide he created i should inflate my 23's to over 200 psi :twitchy:

its funny you mention that. i have such a one track mind, that it didnt occur to me that people ride anything but a pure road bike, with 25-28 max tire width. guess i forgot about my xbike and mnt bike. duh

i treat the minimum pressure guidelines like i do the minimum speed limit on the highway, as do, im sure, the rest of you...a theoretical number, never to be seen in actual life. yeah, i think i once saw a chart that suggested i just ride on my rims, to avoid pinch flats, based on rider weight.

i didnt know there was an accepted position, other than having the ball of the foot, directly over the spindle.

OP: take off your shoes stand and walk on the balls of your feet. Then try this with your heels. You will notice a considerable difference in dexterity. The solution should be obvious.

hello,
i am 6ft 10ins,47 year old and about 330lbs..i cycle with several fit riders over very hilly terrain and we are too competitive at times..anyhows i have my specialised armadillos at 85 psi and have struggled and been lagging behind..feels like riding with the brakes on!..now 6 weeks after last pump tyres seem a littlr deflated and riding is easier...logic suggests higher psi = less tyre on the deck=less friction etc etc but, i am finding it easier ridng lower psi ...any thoughts?
BTW which part of your foot do you taller fellas use to pedal?..i have tried the ball,arch and now finding the heel gives me a little more drive..the ball stretches my leg muscles a lot at times..
cheers
mark
plymouth
ukMore likely you got fitter. Harder tires are faster/easier. If you prefer riding with your heel on the pedal, your seat height may be a tad low.

Depends on riding conditions. On rough chip and seal pavement or sectioned concrete, lower pressure will ride easier and faster. On smooth, new asphalt, or a velodrome (not likely for many of us), pump it to the max.

Essentially, it takes energy to bounce you and your bike around, and the more you and your bike are bouncing the more energy it takes.
That makes a lot of sense. Do you know of any research on the issue?

I feel sluggish pedaling anything other than rock hard tubes. Big dudes can make squishy tires.

That makes a lot of sense. Do you know of any research on the issue?

When analyzing the system, you really need to consider energy. When you hit a bump you translate horizontal momentum into vertical momentum. In most cases, this does not get translated back into the horizontal momentum (a pump track is a noticeable exception). It gets bled from the tire bouncing. That flexes the tire wall which translates kinetic energy into heat energy. The heat energy then just drifts away.

In general the bumpier a surface gets, the more prudent it is to lower tire pressure. To a degree ... you don't want pinch flats. XC racers run tubeless and put as little pressure in their tires as is possible.

It's reasonable that road racers inflate their tire to a maximum. A well paved road does not require a highly compliant tire. At some point though, you wont gain any roll resistance from more psi. Your psi will require experimentation.

The manufacturers started testing rolling resistance on steel drums a few decades ago. This may have been a big step backwards, as those tests showed that rolling resistance decreases with increased air pressure -- no exceptions. The problem is that the real world is not a smooth steel drum. It turns out that over real-world roads -- ie. ones with bumps -- narrow high pressure tires aren't always as fast as wider lower pressure tires, and that increasing pressure in those narrow tires can make them even slower. Essentially, it takes energy to bounce you and your bike around, and the more you and your bike are bouncing the more energy it takes. The bouncing you and your bike will do when riding, for instance, cobblestones on 19 mm clinchers at 180 PSI sucks up a surprising amount of energy, and if you've tried it, you'll know how much it slows you down. Try a pair of 28 mm tubulars with 90 PSI and you'll actually go faster -- and without nearly so much bouncing. Hmm...

I have no experience with Specialized Armadillos, and I have no idea what a bike feels like with 330 pounds aboard, but perhaps the above ideas may be useful for the OP.

If you're on a bike with thin tires and you're actually bouncing up and down, you're doing something wrong. 19mm @ 180 psi on cobblestones? It wouldn't be bouncing that slows you, it would be just trying to stay in control. Most people riding on the road are not on cobblestones - or 180psi razor blades for that matter.

http://books.google.com/books?id=0JJo6DlF9iMC&pg=PA226&lpg=PA226&dq=tire+rolling+resistance+and+road+roughness&source=bl&ots=TrWGDPeqh5&sig=fKRjnndikhczhAIiYX4ySHNLXQc&hl=en&ei=zQjRSd_rFpOdlQfWsentDw&sa=X&oi=book_result&resnum=1&ct=result#PPA226,M1

If you're on a bike with thin tires and you're actually bouncing up and down, you're doing something wrong.

Maybe you can give some lessons to these guys (http://www.youtube.com/watch?v=rkZBDcmXI-w&feature=related), then. :rolleyes:

That makes a lot of sense. Do you know of any research on the issue?

To the best of my knowledge, the work reported in Bicycle Quarterly is the most definitive to date. They have repeatably demonstrated that under real world conditions, wider tires (at least up to 27 mm or so) have lower rolling resistance than narrower (19-20 mm) ones of otherwise identical construction.

Maybe you can give some lessons to these guys (http://www.youtube.com/watch?v=rkZBDcmXI-w&feature=related), then. :rolleyes:

Exactly my point. Do you see those riders bouncing up and down? No, they're not. They're bracing and taking the load with their legs; the center of mass of the bike and rider is not really moving much at all. And they're not going slow because of rolling resistance.

Further, it's ridiculous to use Paris-Roubaix as an example of how the average recreational road cyclist should run his bicycle and tires. Motorcyclists don't set up their bikes for canyon-jumping either.

Exactly my point. Do you see those riders bouncing up and down? No, they're not. They're bracing and taking the load with their legs; the center of mass of the bike and rider is not really moving much at all. And they're not going slow because of rolling resistance.

Further, it's ridiculous to use Paris-Roubaix as an example of how the average recreational road cyclist should run his bicycle and tires. Motorcyclists don't set up their bikes for canyon-jumping either.

Yes, I see the riders bouncing, and yes, I see their bicycles bouncing as well. I've raced on cobblestones. They bounce you around and they slow you down significantly. It is normal to fit wider tires and run them at lower pressures for such events, as they result in less bouncing and higher speeds.

As for the validity of the example, it is simply an extreme instance used to illustrate the principle. Wide tires at lower pressures handle rough roads better than narrow tires at higher pressures, which has been repeatedly demonstrated. It is up to the individual rider to find the correct combination for his own circumstances, while ignoring folks who claim that narrower tires at higher pressures are always faster.

Yes, I see the riders bouncing, and yes, I see their bicycles bouncing as well. I've raced on cobblestones. They bounce you around and they slow you down significantly. It is normal to fit wider tires and run them at lower pressures for such events, as they result in less bouncing and higher speeds.

As for the validity of the example, it is simply an extreme instance used to illustrate the principle. Wide tires at lower pressures handle rough roads better than narrow tires at higher pressures, which has been repeatedly demonstrated. It is up to the individual rider to find the correct combination for his own circumstances, while ignoring folks who claim that narrower tires at higher pressures are always faster.

Whenever this topic comes up, the retrogrouches come in and mention two things: the Bicycle Quarterly "paper" that no one seems to have, and the Paris-Roubaix race (as if that has anything to do with rolling resistance).

My question is simply this: given that most road riding is on asphalt, and that most road racing is on asphalt, why do the racers use thinner tires at high pressures if they are not faster for those conditions, and how could we, the great unwashed masses of cycling, be wrong in using similar equipment if our goal is speed?

thoughts about cornering? many of us heavier types ride crits and crits alone, so im wondering if yall think a 21@140 grip as well as a 25@115? i have my opinion, just wondering about yours.

Whenever this topic comes up, the retrogrouches come in and mention two things: the Bicycle Quarterly "paper" that no one seems to have, and the Paris-Roubaix race (as if that has anything to do with rolling resistance).

My question is simply this: given that most road riding is on asphalt, and that most road racing is on asphalt, why do the racers use thinner tires at high pressures if they are not faster for those conditions, and how could we, the great unwashed masses of cycling, be wrong in using similar equipment if our goal is speed?

The "paper" is BQ volume 5 number 1. I am looking at it right now. You can order one for yourself here (http://www.vintagebicyclepress.com/subscriptioninfo.html).

Regarding Paris-Roubaix, the argument is that fatter tires at lower pressures can be faster on rougher roads. Being as Paris-Roubaix involves cyclists using wider tires at lower pressures to go faster on rougher roads, it seems to me a valid example. If it makes you feel better I will substitute the Tour of Flanders for Paris-Roubaix in the future.

In answer to your question, racing cyclists must balance rolling resistance with tire weight. When climbing and acceleration are not factors, riders often do choose wider tires. This can be seen in trends for hour record attempts on the track. But most races do involve accelerations and climbs, and the typical racer has found that tires in the neighborhood of 23mm appear to offer the best compromise for their purposes. Of course, once the road gets rougher, they switch to wider and wider tires. A detective would call that a clue.

Having said that, if your circumstances are exactly the same as a professional road racer's then you will hardly go wrong emulating their tire choices. Why that needs to be said in the context of my claim that "on bumpy roads, narrow high pressure tires aren't always as fast as wider lower pressure tires" -- let alone in the context of a 6' 10" 330 pound 47 year old riding Specialized Armadillos at less than 85 PSI -- is beyond me.

The point is that it's probably a good idea to evaluate your own needs and riding conditions without feeling the need to cling to the "narrower is always faster" dogma.

Whenever this topic comes up, the retrogrouches come in and mention two things: the Bicycle Quarterly "paper" that no one seems to have, and the Paris-Roubaix race (as if that has anything to do with rolling resistance).

My question is simply this: given that most road riding is on asphalt, and that most road racing is on asphalt, why do the racers use thinner tires at high pressures if they are not faster for those conditions, and how could we, the great unwashed masses of cycling, be wrong in using similar equipment if our goal is speed?

Racers are willing to pay any price for speed, super light weight and expensive bikes, uncomfortable riding positions and rock hard tires are part of that. Even when the benefits may only shave 1/10th of a second off the time of a 100 mile race. Is the rolling resistance on a 21mm tire at 140PSI going to be less then a 23mm tire at 120PSI, yeah probably, will it be enough that your 100 mile time of 5:21:15 will suddenly turn into 4:21:15, well no, your more likely with that 2mm narrower tire, all other conditions being equal going to turn in a time of 5:21:14, of course with the 20PSI higher needed, you will, however, probably end up paying for your dentists new Porsche in that the rough ride knocked all your fillings out.:eek: One factor nobody seems to take into account is that wind resistance is a much bigger factor, which is why the racer has the bars a foot lower then the saddle. I don't know about where you ride, around here, especially this time of year, the asphalt can be almost as bad as cobblestones. So a rolling resistance improvement of .1% isn't going to make any difference.

For those of us here in C & A a wider, lower pressure tire and a more upright riding position, will make for a slightly slower, but more comfortable ride. A comfortable rider is going to be more likely to go ride, and that is the important thing.

Is the rolling resistance on a 21mm tire at 140PSI going to be less then a 23mm tire at 120PSI

The BQ test that nobody but me has (:p) tested the Michelin Pro2 Race in widths of 21mm, 23.5mm, and 25.5mm. The narrowest tire completed the test in 27.4 seconds, the middle tire in 27.1 seconds, and the widest tire in 26.8 seconds. Were weight not an issue (are you riding in a crit with constant accelerations, or out all day on the century route at a steady pace?) the choice would be obvious.

The BQ test that nobody but me has (:p) tested the Michelin Pro2 Race in widths of 21mm, 23.5mm, and 25.5mm. The narrowest tire completed the test in 27.4 seconds, the middle tire in 27.1 seconds, and the widest tire in 26.8 seconds. Were weight not an issue (are you riding in a crit with constant accelerations, or out all day on the century route at a steady pace?) the choice would be obvious.

Were all conditions other then tire width normalized? Were tire widths measured or were they values printed/embossed on the tire. Were multiple runs taken and averaged or was it a single run? If multiple runs were they always done in the same order, or was the order changed?

For those of us here in C & A a wider, lower pressure tire and a more upright riding position, will make for a slightly slower, but more comfortable ride. A comfortable rider is going to be more likely to go ride, and that is the important thing.

Which is 100% correct and fine. Just say it that way, and don't bother with this hair-splitting argument about rolling resistance and how wider tires are faster.


Were all conditions other then tire width normalized? Were tire widths measured or were they values printed/embossed on the tire. Were multiple runs taken and averaged or was it a single run? If multiple runs were they always done in the same order, or was the order changed?

Exactly. What are the conditions? Was it scientifically controlled? Call me biased but I'm extremely disinclined to blindly take the word of authors with the very clear toe-clip/quill stems/fat tire/"steel is real" kind of inclinations.

Which is 100% correct and fine. Just say it that way, and don't bother with this hair-splitting argument about rolling resistance and how wider tires are faster.



Exactly. What are the conditions? Was it scientifically controlled? Call me biased but I'm extremely disinclined to blindly take the word of authors with the very clear toe-clip/quill stems/fat tire/"steel is real" kind of inclinations.

Anyone who has taken basic statistics knows that and set of numeric data can be used to prove anything, which is why I asked the questions.

I think we're on the same page here. :thumb:

Were all conditions other then tire width normalized? Were tire widths measured or were they values printed/embossed on the tire. Were multiple runs taken and averaged or was it a single run? If multiple runs were they always done in the same order, or was the order changed?

Yes.

Actual tire width measured with calipers.

Multiple runs, and repeated on several different days. The order of runs was randomized. Results were found to be highly repeatable, including later results produced in subsequent (months to years later) tests.

A statistical analysis (including ANOVA) was performed on the results. The ratio of explained to unexplained variance was 151 to 1 and overall confidence was 99.99%.

Call me biased but I'm extremely disinclined to blindly take the word of authors with the very clear toe-clip/quill stems/fat tire/"steel is real" kind of inclinations.

Editor Jan Heine prefers clipless pedals. One of his favorite and most used bikes has an early version of a threadless stem clamped directly to the steerer. And BQ has favorably tested bicycles made of titanium, aluminum, and carbon fiber. He is biased in favor of wider tires, which probably stems at least partly from being one of the fastest finishers in the most recent PBP and setting multiple course records in ACP brevets while riding 30mm tires.

I remember when I started doing longer road rides as a teenager, by the time I had done 90km in a day I always thought my rear tire was going flat or my brakes were dragging. To this day I get on my generally perfectly functioning bike and I stop to check for brake/tire/bearing problems just because I am having a bad day.

My probable diagnosis: It's not the bike. The OP is a stronger rider now than he was months ago.

To the OP: Run your tires at whatever pressure you feel most comfortable, but running the pressure too low (especially on narrow tires) will almost certainly lead to punctures.