aero or lite?

Hi, look around in photos of pros racing: Time trials: disc wheel and tri spoke. Reason: each spoke cuts the air flow over the wheel and disrupts it. So a wheel with fewer spokes goes through the air smoother --> faster. However since money is of concern for you (and me and many other people, I'm sure) try going for a second hand wheel in good condition.

If you can't afford Zipp wheels (which are really good), go for a similar wheelset, such as Mavic Cosmic wheels (if they are cheaper, I'm not sure). Another possibility to avoid this disruption of the air with the spokes is to buy wheels that have spokes in groups, such as in pairs of twos, or threes instead of evenly spaced ones. See canadiancyclist.comshimano wheels2.jpgOpen ↗ for an example of such wheels.

In answer to your question: light weight is important for climbing because then gravity has greater effect than aerodynamics. However in a time trial, you want aero wheels more than light ones. This might be slow to accelerate with, but you only accelerate once in a time trial. Stiffness: correct me if I'm wrong, and I could be, but stiffness is more important on climbing than flat road, so if you mostly ride hills, opt for stiff wheels as opposed to "less stiff".

Also if you want long lasting wheels, Id avoid carbon fiber, becasue once you have an accident and you have a crack in the wheel, you can say goodbye to it and throw it away, becase as far as I know, you cant repair carbon products. So go for less expensive metal wheels, which can be fixed in the unpleasant event of say, an accident.

For rolling hills might I reccomend the Zipp 303 wheelset, as they're a balance between flat road aero wheels and light weight climbing wheels.

You could also combine two wheels, for example a trispoke in the back and a "normal" wheel in the front, although it looks nicer to have the same wheels.

If you are a skilled (whats the word...) artist? measure your wheel and cut a cardboard circle, then some how stuff that in your wheel, inbetween the spokes and you have a cheap, homemade discwheel! Warning: could be risky and probably not worth testing on windy days.😉

I hope this information helps, take care, and keep riding!
Jaco

If you read much in here, and once this topic get longer, you'll see many people recommend you stay away from shimano (durability) and mavic (over marketed).

With what you can likely afford, you won't get super lite or super aero, but trust me once you have a decent set of wheel you should worry more about the motor driving them than the drag coeffiecent.

I assume you have shimano running gear, so look at the fulcrum range of wheels. From the racing 3 upwards they use fantastic campy hubs (not the cheaper wheels use bad hubs, they are still cheaper campys) and campy/fulcrum wheels are very tough, resonably lite, and moderately aero for this class of wheels.

I've got one set of wheels, and have older zondas (same level as racing 3s). I'm 98kg and have put over 8000kms on the front wheel, and 6000 on the rear, and they are still straight and true. Going to get the hubs serviced because I think I should, not because they roll any slower....they roll fantastically!

Stiff.

Get a set of handbuilts. Contact Ligero wheelworks, or PM bikemesenger or ergott from WeightWeenies forum. They are reputable wheelbuilders.

From the wheels I've measured, I've been able to notice some trends in the data. The following are important for good performance:

- Aerodynamics improves with rim depth. A deeper rim also makes the wheel more rigid laterally.
- Rotational aerodynamics is better with fewer spokes. However, this makes the wheel less rigid laterally.
- For aerodynamics, smaller spokes are better than large spokes and bladed are better than round.
- Good hubs that are well adjusted reduce the amount of bearing friction. A good amount of the friction is in the bearing seals. They rub (they're supposed to in order to keep out water) and cause drag.

I should also add that durability is a completely separate issue. It's possible to make a wheel with fantastic performance, but does not hold up to regular riding. I don't know of any real way to measure that. I guess looking for reviews for a particular wheelset would give some info.

What is not important:

- Weight is not very important. The differences in weight and moment of inertia that I have measured amount to incredibly small changes in performance.
- Ceramic bearings do not make a large difference. SKF has come up with an excellent "bearing drag model" that is heavy on the physics and engineering. Using that tool, I figure the average improvement will be ~0.2 Watts per wheel at 40 km/hr. That should be a good approximation, anyways.

And without analyzing any data, my personal bias is that good tires make a big difference in ride quality if not performance. I just bought an expensive set of Deda Tre "Open Tubular RS Corsa" tires. I'll be taking them out on their first ride in a few minutes... 🙂

I hope that helps.

John Swanson
www.bikephysics.com

ScienceIsCool said:

I just bought an expensive set of Deda Tre "Open Tubular RS Corsa" tires. I'll be taking them out on their first ride in a few minutes... 🙂

I hope that helps.

John Swanson
www.bikephysics.com

Aside from the fact that they are expensive, where did you get these? They are supposedly one of the fastest rolling tyres, better than Vittoria Evo Corsa CX, but they are impossible to find. If I remember comobike had some?

That brings us all to a point. If you want speed, don't skimp on tyres. They can transform a bike.

mr handy said:

anyway what is the general consensus on the subject, for solo riding on rolling to flat roads, go aero or lite weight for the best performance?

Strong, durable, repairable handbuilts. For 150 lb, 32 spokes in back, 28 in front, both 3 cross. Record (or DA) hubs, Open Pro or equivalent rim. Brass nipples, or alloy if you want to live a little more dangerous. Built by someone who knows what they are doing, they will likely never let you down.

bobbyOCR said:

Aside from the fact that they are expensive, where did you get these? They are supposedly one of the fastest rolling tyres, better than Vittoria Evo Corsa CX, but they are impossible to find. If I remember comobike had some?

That brings us all to a point. If you want speed, don't skimp on tyres. They can transform a bike.

After yesterday's ride, I realized that I needed some new tires. The only shop open was Campione Cycles ( www.campionecycles.com - still under re-construction). That was fine by me because it's a geat shop and I hadn't been there in a while. It's run by Guiseppe Cramerotti who raced in Italy then came to Canada to build frames. He has many connections back in Italy (Campagnolo family primarily) and can get some really great products at unbelievable prices.

While talking to him about tires he recommended the Deda Tres. Since they had just arrived (he had to go to the back and pull some out of a box) and I was the first to buy them he gave me a great deal. Yay! I put in 100 km with the team this morning and they were incredible. I hit all kinds of conditions, too. Rough pavement, sand, wet roads, dry roads, smooth roads. The works.

I don't know if he would, but you can always email Guiseppe and ask if he would send some to you in Australia.

John Swanson
www.bikephysics.com

bobbyOCR said:

Aside from the fact that they are expensive, where did you get these? They are supposedly one of the fastest rolling tyres, better than Vittoria Evo Corsa CX, but they are impossible to find. If I remember comobike had some?

That brings us all to a point. If you want speed, don't skimp on tyres. They can transform a bike.

Fairwheel Bikes always has them, and they have a web presence, and a forum, and about every lust worthy bike part available to man.

ScienceIsCool said:

After yesterday's ride, I realized that I needed some new tires. The only shop open was Campione Cycles ( www.campionecycles.com - still under re-construction). That was fine by me because it's a geat shop and I hadn't been there in a while. It's run by Guiseppe Cramerotti who raced in Italy then came to Canada to build frames. He has many connections back in Italy (Campagnolo family primarily) and can get some really great products at unbelievable prices.

While talking to him about tires he recommended the Deda Tres. Since they had just arrived (he had to go to the back and pull some out of a box) and I was the first to buy them he gave me a great deal. Yay! I put in 100 km with the team this morning and they were incredible. I hit all kinds of conditions, too. Rough pavement, sand, wet roads, dry roads, smooth roads. The works.

I don't know if he would, but you can always email Guiseppe and ask if he would send some to you in Australia.

John Swanson
www.bikephysics.com

Good things are said about these tires--awesome rolling resistance--but one thing that isn't said about 'em is that they last a long time.

Man, you need to build yourself a rolling resistance test apparatus. And for the sake of the doubters, you could have one drum that is smooth driving the tires under test, then you could switch to a bumpy drum for driving the tires. It doesn't have to be a Roubaix drum, but I think the idea that smooth surfaces for testing rolling resistance are flawed...well, I think that idea needs to be addressed and given a humane assisted suicide.

As you've read elsewhere, I'm sure--I'm sure because you don't seem to miss much, John (FWIW, us physicists need to stick together.).--a lot of people are diggin' the Ultremo clinchers. From my experience with them so far, they seem to roll uber well, better, at least than the Carbons, GP4000's, Hors Categorie, and etc that I've used in the past. Of course, my feelings could amount to squat. Still, they corner uber confidently, with no dramas even when you're sure you've over-cooked that corner, and they're very confident in the rain, way better than any Michelin tire I've run in the rain. As a bonus, they seem to be wearing very well. I've got 1000+ miles on 'em, and I've got zero cuts...and that's all desert riding.

I'm nearly wetting myself waiting for the Ultremo tubulars. If my ass-o-meter is correct and the rolling resistance on the Ultremo clinchers is impressively low, then that bodes mucho well for the tubulars. They say that increased flat resistance comes at the expense of rolling resistance, but maybe this vectran belt has comparitively low hysteresis.

In my wait for Ultremo tubulars, I'm half tempted to try the Conti tubular Gatorskin tubies.....but I've been very unimpressed by Conti tires in the past. Gatorskin Sprinter carcass is less supple than my Ultremo clincher carcass, and I don't think a lot of Conti sidewalls or flat protection. I flatted GP4000's two or three times in the first two weeks I had 'em.

alienator said:

Good things are said about these tires--awesome rolling resistance--but one thing that isn't said about 'em is that they last a long time.

Man, you need to build yourself a rolling resistance test apparatus. And for the sake of the doubters, you could have one drum that is smooth driving the tires under test, then you could switch to a bumpy drum for driving the tires. It doesn't have to be a Roubaix drum, but I think the idea that smooth surfaces for testing rolling resistance are flawed...well, I think that idea needs to be addressed and given a humane assisted suicide.

As you've read elsewhere, I'm sure--I'm sure because you don't seem to miss much, John (FWIW, us physicists need to stick together.).--a lot of people are diggin' the Ultremo clinchers. From my experience with them so far, they seem to roll uber well, better, at least than the Carbons, GP4000's, Hors Categorie, and etc that I've used in the past. Of course, my feelings could amount to squat. Still, they corner uber confidently, with no dramas even when you're sure you've over-cooked that corner, and they're very confident in the rain, way better than any Michelin tire I've run in the rain. As a bonus, they seem to be wearing very well. I've got 1000+ miles on 'em, and I've got zero cuts...and that's all desert riding.

I'm nearly wetting myself waiting for the Ultremo tubulars. If my ass-o-meter is correct and the rolling resistance on the Ultremo clinchers is impressively low, then that bodes mucho well for the tubulars. They say that increased flat resistance comes at the expense of rolling resistance, but maybe this vectran belt has comparitively low hysteresis.

In my wait for Ultremo tubulars, I'm half tempted to try the Conti tubular Gatorskin tubies.....but I've been very unimpressed by Conti tires in the past. Gatorskin Sprinter carcass is less supple than my Ultremo clincher carcass, and I don't think a lot of Conti sidewalls or flat protection. I flatted GP4000's two or three times in the first two weeks I had 'em.

Heh. I have a much crazier idea that a rough drum for Crr testing... I'm considering mounting a long boom to the front of a car. One that can pivot up and down. On the end of that boom, mount a wheel with load cells to measure the force, or drag. Combine that with a DAQ unit and simultaeously measure speed, wind speed, wind direction, temperature and humidity and you have a killer lab setup!

You could preload the boom to measure the effect of rider weight versus rolling resistance. You could measure tire pressure versus resistance. Tire type. Aerodynamics, bearing type, wind speed and direction. The tests you could do would be endless! The cool thing is that with my laptop and DAQ, all I'm really missing is a wind speed/direction indicator and a boom rig....

BTW, all this came out of my thoughts on how to build a cheap wind tunnel. 🙂

John Swanson
www.bikephysics.com

ScienceIsCool said:

Heh. I have a much crazier idea that a rough drum for Crr testing... I'm considering mounting a long boom to the front of a car. One that can pivot up and down. On the end of that boom, mount a wheel with load cells to measure the force, or drag. Combine that with a DAQ unit and simultaeously measure speed, wind speed, wind direction, temperature and humidity and you have a killer lab setup!

You could preload the boom to measure the effect of rider weight versus rolling resistance. You could measure tire pressure versus resistance. Tire type. Aerodynamics, bearing type, wind speed and direction. The tests you could do would be endless! The cool thing is that with my laptop and DAQ, all I'm really missing is a wind speed/direction indicator and a boom rig....

BTW, all this came out of my thoughts on how to build a cheap wind tunnel. 🙂

John Swanson
www.bikephysics.com

Cheap wind tunnel? Man, with $125,000 in your pocket, you could have the Abe Silverstein wind tunnel at NASA Glenn research center, complete with all the technicians to run it and the ability to hit mach 2.5!

alienator said:

I flatted GP4000's two or three times in the first two weeks I had 'em.

Per your comments in the other thread , that amounts to a nasty monsoon and luck. 😉

ScienceIsCool said:

From the wheels I've measured, I've been able to notice some trends in the data. The following are important for good performance:

- Aerodynamics improves with rim depth. A deeper rim also makes the wheel more rigid laterally.
- Rotational aerodynamics is better with fewer spokes. However, this makes the wheel less rigid laterally.
- For aerodynamics, smaller spokes are better than large spokes and bladed are better than round.
- Good hubs that are well adjusted reduce the amount of bearing friction. A good amount of the friction is in the bearing seals. They rub (they're supposed to in order to keep out water) and cause drag.

I should also add that durability is a completely separate issue. It's possible to make a wheel with fantastic performance, but does not hold up to regular riding. I don't know of any real way to measure that. I guess looking for reviews for a particular wheelset would give some info.

What is not important:

- Weight is not very important. The differences in weight and moment of inertia that I have measured amount to incredibly small changes in performance.
- Ceramic bearings do not make a large difference. SKF has come up with an excellent "bearing drag model" that is heavy on the physics and engineering. Using that tool, I figure the average improvement will be ~0.2 Watts per wheel at 40 km/hr. That should be a good approximation, anyways.

And without analyzing any data, my personal bias is that good tires make a big difference in ride quality if not performance. I just bought an expensive set of Deda Tre "Open Tubular RS Corsa" tires. I'll be taking them out on their first ride in a few minutes... 🙂

I hope that helps.

John Swanson
www.bikephysics.com

Are bladed spokes stronger than round spokes and therefor you can use less.

Where's the tradeoff point between less spokes (greater aero) and more spokes (lateral strength)

mikesbytes said:

Are bladed spokes stronger than round spokes and therefor you can use less.

For a given material, it's mostly about the cross-sectional area and material. Greater area means stronger spokes, stiffer spokes, for a given material. Ksyrium spokes are so damned big because they're aluminum and they need to be that big to give a sufficient stiffness and yield strength. You'll notice that the Ksyriums are decidedly lacking in lateral stiffness, largely because of their aluminum spokes.

mikesbytes said:

Where's the tradeoff point between less spokes (greater aero) and more spokes (lateral strength)

This is design dependent. As a rule fewer spokes are more aero, yet paired spoke designs with low spoke counts aren't so aero as you would think. You should also factor in the the idea that deeper rims are stiffer and can get a way with fewer spokes. Again, what the cross-over point is really depends on the wheel in question.

There are some manufacturers who are claiming that they're bringing to market relatively traditionally spoked wheels that are more aero than the HED 3. That's pretty damned aero.

Wheel aerodynamics is not a simple thing. Not only do have to translate the wheel along your route, but while it's translating it's rotating. How the air flows over the translating, rotating wheel is tough to model. Personally, I think even the wheel manufacturers don't have all that stuff figured out. Cees Beers, of ADA fame and once of Lightweight Wheels famed, has poopoo'd the new LEW wheels; yet LEW is making claims that would seem to defy Mr. Beers knowledge.

All in all, these are very interesting times for wheel development: Zipp wants to dimple everything and says said dimpling helps. There's no doubt that the 404 wheelset is one aero wheelset. Mavic has brought the Ultimate Carbone to the dance, and with it, they brought, according to them, one seriously aero and laterally stiff wheelset. LEW is bringing a set of wheels that weighs less than 900g yet is supposed to be damned strong, as well as aero. And there are others. Edge Composites--former LEW guys--are bringing new wheels/rims out, and M5 is spending no small amount of money developing their 50mm deep rims and their hubs.

alienator said:

Cees Beers, of ADA fame and once of Lightweight Wheels famed, has poopoo'd the new LEW wheels; yet LEW is making claims that would seem to defy Mr. Beers knowledge.

Have you had your chance to test those new LEW wheels yet? How does it match up to its price tag? 😉

sogood said:

Have you had your chance to test those new LEW wheels yet? How does it match up to its price tag? 😉

Nah, they're not at the shop yet. LEW wants shop man to go to Reno and do the whole hotel stay and ride test, while also picking up his demo wheels. Said shop guy is just busy, right now, maintaing the forum, ordering parts, distributing parts (The shop is the US distributor for Carbon Ti, among others.), and building seriously lust-worthy bikes. In the interim, I get a little time to build up a potential LEW wheel warchest.

I wait with baited breath.

alienator said:

Nah, they're not at the shop yet. LEW wants shop man to go to Reno and do the whole hotel stay and ride test, while also picking up his demo wheels. Said shop guy is just busy, right now, maintaing the forum, ordering parts, distributing parts (The shop is the US distributor for Carbon Ti, among others.), and building seriously lust-worthy bikes. In the interim, I get a little time to build up a potential LEW wheel warchest.

I wait with baited breath.

Here's an idea. You can volunteer to go in place of the "shop guy". 😉