Australian Cycling Forums - Bicycles Network Australia

you don't really feel wheels accelerating faster

what you feel is the money you spent on them

ohexploitable wrote:you don't really feel wheels accelerating faster

what you feel is the money you spent on them

Get the smoothest running hubs and have the best tubs/singles you can afford and your rolling ressistance will notice the difference. Plus have them the wheels nice and stiff. You don't need to spen a gazillion dollars, just buy smart.

Foo

winstonw wrote: God said heavier aerodynamic wheels are better than lighter aerodynamic wheels, and the more aero the better.

Alpine Classic Extreme. (Note: most of this route is little affected by wind)
Target time 11 hours. (I have grey hair and bifocals)
1500 gram non-aero wheels or 1900 gram, 80 mm deep section, 20/24 conventional spoke wheels.

Which will be faster? Please show your calculations.

ausrandoman wrote:

winstonw wrote: God said heavier aerodynamic wheels are better than lighter aerodynamic wheels, and the more aero the better.

Alpine Classic Extreme. (Note: most of this route is little affected by wind)
Target time 11 hours. (I have grey hair and bifocals)
1500 gram non-aero wheels or 1900 gram, 80 mm deep section, 20/24 conventional spoke wheels.

Which will be faster? Please show your calculations.

Is that aerodynamic grey hair? (I have neglected hair) What is the cost/benefit of dyeing hair?

Marto wrote:

ausrandoman wrote:

winstonw wrote: God said heavier aerodynamic wheels are better than lighter aerodynamic wheels, and the more aero the better.

Alpine Classic Extreme. (Note: most of this route is little affected by wind)
Target time 11 hours. (I have grey hair and bifocals)
1500 gram non-aero wheels or 1900 gram, 80 mm deep section, 20/24 conventional spoke wheels.

Which will be faster? Please show your calculations.

Is that aerodynamic grey hair? (I have neglected hair) What is the cost/benefit of dyeing hair?

As everybody knows, red goes faster, plus you wouldn't be weighed down by a soul.

lump_a_charcoal wrote:

Marto wrote:

ausrandoman wrote:
Alpine Classic Extreme. (Note: most of this route is little affected by wind)
Target time 11 hours. (I have grey hair and bifocals)
1500 gram non-aero wheels or 1900 gram, 80 mm deep section, 20/24 conventional spoke wheels.

Which will be faster? Please show your calculations.

Is that aerodynamic grey hair? (I have neglected hair) What is the cost/benefit of dyeing hair?

As everybody knows, red goes faster, plus you wouldn't be weighed down by a soul.

Oh, but I am not weighed down by a soul. I have photographic evidence!



It's hard to be aerodynamic when it is %#*&^ing cold - except for shoe covers. I shoulda worn shoe covers.

ausrandoman wrote: (Note: most of this route is little affected by wind)

I would have thought nearly half of the distance would be spent at 40 kmph plus

toolonglegs wrote:

ausrandoman wrote: (Note: most of this route is little affected by wind)

I would have thought nearly half of the distance would be spent at 40 kmph plus

Good point!

Mulger bill wrote:

ausrandoman wrote:The most important contribution to improved performance is lower aerodynamic drag with reduced weight second.

My popcorn machine's broken and I can't read about NV wheels without it...

Got enough popcorn yet?

il padrone wrote:Strewth, how does a full tuck with aero bars cost $3000 Nah, nah, forget the wheels and the skinsuit. Get with the real aero plan

Look another data table!!

I can only assume the "Good regular bicycle" is an upright of some kind, not a drop bar. Also the UCI (I assume TT) bike still seems too good to be true, 137W at 30Km/h?

il padrone wrote:Can I ride the neglected bicycle.... please....please....??


Oh !?

Looks like it was a hot day.

ausrandoman wrote:It's hard to be aerodynamic when it is %#*&^ing cold - except for shoe covers. I shoulda worn shoe covers.

Found It!

It's the mirror that's making it hard for you, you NEED something like this...

Of course the CF version at half the weight and 17 times the price will be better again.

Methinks the "upright" posture caused by the ped you just passed won't be helping either...

Lovin' dat popcorn!

Mulger bill wrote: ... you NEED something like this...

Of course the CF version at half the weight and 17 times the price will be better again.

Hey, I like the idea of the carbon fibre version! If it's half the weight, I can use two, one on each side of the handlebars, thereby avoiding aerodynamic instability. And the extra expense will make me go even faster!

And winstow is right, if pure speed is the key, then shoe covers and skinsuits should be your first port of call if you aren't doing much climbing. Of course, there is more to the story than just that, but it's a good starting point.

In answer to the OP's question (and this is not based on experience, just collation of data) all the wheelset improvement reviews I've read seem to imply a more positive feeling from the wheels. I'm guessing you probably won't notice it without swapping wheels around. At least they are easy to swap compared to frames

Xplora wrote: In answer to the OP's question (and this is not based on experience, just collation of data) all the wheelset improvement reviews I've read seem to imply a more positive feeling from the wheels. I'm guessing you probably won't notice it without swapping wheels around. At least they are easy to swap compared to frames

The better wheelsets, designed for speed and handling improvements, are noticeably stiffer and feel more stable and solid especially when cornering. This is an actual physical difference you will definitely notice, especially when swapped onto a bike/wheel package that may have been designed with some comfort in mind.

As mentioned earlier, when you get a road bike package for, say, up to $1500-2000, you have the basis of an excellent setup. The single biggest improvement would then to be to spend perhaps up to $500 on a lighter, stiffer, slightly aero wheelset for those days you want to ride faster.

That has been my experience.

Thanks Cyclotaur, nice reasoning.

But seriously,

There are some nice looking wheels and ride like a dog.

I had Mavic Aksium wheels on a nice Bianchi and over 50Kph the bike suddenly felt like I had flatted. Everything looked ok but I reluctantly rode off waiting for something to happen.
Long story short, the design of the wheels was for show, not go and once the wheels got to a certain speed the dynamics of poor design made the wheel twist and squirm under pressure. The spokes were straight pull, crossed twice on the drive and none on the other. The drive side spokes also didn't touch each other which also attributed to poor lateral strength. In short they were good for show and riding around the park.

A tip I got from an ex tour mechanic was to change the pattern so the spokes crossed over each other (touching). Tension to the max and absolute even tension on the drive side and use the non drive to finely true the wheel. All was well after that but I was still cautious. Handling did noticeably improve heaps. Particularly winding descents.

You could say you can make cheap wheels better by knowing a few things like this but a good wheel builder will know it already and may be the person/s to talk to.

^^^ Aksiums aren't really better than much though... "no name generic machine built Chinese trash" isn't really a benchmark. I've personally found my Bontragers on my 2.1 and 5.2 2012's to be quite serviceable riding up to 70kph, hubs are OK? I think the OPs comparison point would be 600-800 dollar wheelsets? I recall Aksiums only being 200-300? Either way, awesome that they got so much better after a bit of wangling.

Aksiums have changed slightly from mine.
They are cheap, both cost and quality and I wouldn't go out of my way to buy any. But they can be improved to be a reasonable wheel.

There are other subtle considerations to look at also. Width of spoke flanges. Wider the better. Types of bearings used and if they can be adjusted. A very slight preload is preferred but some mechanics don't know what slight is. You can take the preload away, remove the seals and your wheel will spin forever but... reliability and stability are at risk.

Depth and width of rim, single wall or double, eyelet spoke holes or none. Deeper rim is stronger but harsher and can accommodate less spokes for the same strength.
Aero yes! over 30kph.

What do you need?... What do you want? Silly question really, Want wins nearly every time.

I had this conversation with my brother a while ago. Him being the smart arse physics guy that he is said that the part of the bike that dose the most work (eg moves the most) is the wheels. So while the weight difference between wheel sets is small because they are moving so much it creates a larger difference.

I'm not sure any of this makes sense to anyone reading it but it makes perfect sense in my head and no I'm not going to do any calculations to prove it (even if I knew how).

Ginantonicus wrote:I had this conversation with my brother a while ago. Him being the smart arse physics guy that he is said that the part of the bike that dose the most work (eg moves the most) is the wheels. So while the weight difference between wheel sets is small because they are moving so much it creates a larger difference.

I'm not sure any of this makes sense to anyone reading it but it makes perfect sense in my head and no I'm not going to do any calculations to prove it (even if I knew how).

And if you consider what is happening when you are riding, then the differences between wheels based on his explanation are almost nothing. The rotation of the wheel is virtually the same for any wheel, assuming it is true and stiff. The actual "moment" (the force of momentum? It's been a while) from a 60mm aero rim and a Chinese alloy factory isn't going to be dramatically different because the wheel is round, and weight will be functionally identical the whole way around. A heavy wheel is 1.2kgs, a light one is 600gms. But how much difference in weight at each "point" along the rim? That is his argument.

The weight is effectively meaningless from a rotational perspective in relation to acceleration, no more important than the weight of the frame. The wheel isn't doing any "work". Aerodynamics is completely different, but even then, the difference in aero between BSO Chinese wheels and Campy discs is going to be 5-10w maybe. Unimportant for "most riders". Critical for racers. But the coffee shop doesn't need discs.

If the wheels were not attached at a central and UNMOVEABLE point (shudder, imagine that leaving the fork), then the movement might make a difference. MTB wheels may vary for this discussion because there is more motion through the tyre and suspension. But a road bike is naturally opposing weight around the rim, and it starts and stops on a constant axis. The difference to change the speed between a good and bad wheel is negligible, because how much does a couple spokes weigh? I wouldn't want to drag extra spokes along the road for aero reasons, but weight really doesn't make much difference.

If your wheels aren't true, and aren't stiff, then you will get a lot more interference from bumps and moments that aren't acting along the "proper" plane, but you need to be pulling some serious watts for this to make a difference I am guessing. I don't feel any functional difference in the wheels I've had, all low/mid level wheels, and varying weights of tyres and spokes as well.

Xplora wrote:The rotation of the wheel is virtually the same for any wheel, assuming it is true and stiff. The actual "moment" (the force of momentum? It's been a while) from a 60mm aero rim and a Chinese alloy factory isn't going to be dramatically different because the wheel is round, and weight will be functionally identical the whole way around.

Xplora, the difference is bringing the two sets of wheels up to the same speed.

As well as linear momentum, there is angular momentum (think of the identical relationship between force/torque), and more effort is needed to accelerate a heavier wheel.

I've seen a claim that in this respect, saving 250g on wheels is like saving a full kilogram on the frame, although no academic reference was given.

The spokes don't matter so much, it's the rim that is furthest away from the axle.

One reason is simple reliability. I got a bulletproof pair built after I hit a pothole and threw two spokes 300Km north of Port Augusta. Interestingly the new wheel added no weight over the WH500 which came with the bike, but the added stiffness has made a huge difference to the handling. Using standard parts is also a good thing, in the worst case I can call my LBS and ask them to put on the bus enough parts to rebuild the wheel at the side of the road.

(CXP33 rims with 32/36 2mm spokes on Ultegra hubs. About $450 for the pair. It does catch crosswinds more than the old wheels, but not enough to be annoying.)

clackers wrote:
Xplora, the difference is bringing the two sets of wheels up to the same speed.

As well as linear momentum, there is angular momentum (think of the identical relationship between force/torque), and more effort is needed to accelerate a heavier wheel.

I've seen a claim that in this respect, saving 250g on wheels is like saving a full kilogram on the frame, although no academic reference was given.

The spokes don't matter so much, it's the rim that is furthest away from the axle.

My explanation hopefully focussed on the difference in those two wheels. There is no way you'll get a kilo difference based on angular acceleration, unless your wheels aren't trued or stiff. True and stiff essentially is reducing resistance to that angular acceleration, but we're talking about the difference between the wheels, not the wheels specifically. It's a subjective measurement - Wheel A of a particular stiffness, weight and trueness is of a benefit over Wheel B.

I think about the actual mechanics in motion and if you don't have an absolute dog wheel to start with, the improvements will be marginal. Aero trumps weight for a reason - the forces involved in accelerating the weight are tiny compared to overcoming wind resistance.

Xplora is correct in saying that the force required to accelerate the wheel rim is tiny compared to aero drag and rolling resistance. Indeed a test showed that the extra force needed to accelerate a rim mass 400g higher was just 1%.

http://www.slowtwitch.com/Tech/Why_Whee ... _2106.html