Wheelbuilders

sogood said:

Thanks for the detail. The question that remains in my mind is, given the same 2:1 spoke ratio, is the G3 pattern on the Campag better than the evenly spaced Fulcrum 2:1 for the rear wheel? Does your argument still apply?

no problem.

to answer fairly, I'd have to see how the Bora wheel and an equivalent Fulcrum wheel look on a stand (with me wielding whatever spoke key it uses, or the Eurus socket wrench that I currently have). Since I haven't, I can't say for sure.

My guess is that the G3 would be slightly better. The tweak to the left will be very short (since the 2 spokes close by are pulling to the right). So the rim should be reasonably straight.

The evenly spaced 2:1 spokes (say, like a Fulcrum) will pull more left since there is more rim that single left spoke affects.

Again, the above are simply theories. If the rims are significantly stiffer, the braking surface not straight, a spoke nipple isn't sitting properly in the rim, etc., my ideas may not apply.

On my Reynolds DV's the rim is strong enough to be reasonably straight with evenly spaced and evenly distributed spokes. So the point may be moot for stiff carbon rims. For AL rims, I noticed the G3 pattern benefits the rear.

hope this helps
cdr

carpediemracing said:

My guess is that the G3 would be slightly better. The tweak to the left will be very short (since the 2 spokes close by are pulling to the right). So the rim should be reasonably straight.

The evenly spaced 2:1 spokes (say, like a Fulcrum) will pull more left since there is more rim that single left spoke affects.

Again, the above are simply theories. If the rims are significantly stiffer, the braking surface not straight, a spoke nipple isn't sitting properly in the rim, etc., my ideas may not apply.

On my Reynolds DV's the rim is strong enough to be reasonably straight with evenly spaced and evenly distributed spokes. So the point may be moot for stiff carbon rims. For AL rims, I noticed the G3 pattern benefits the rear.

Yep, definitely helps and very interesting analysis. Now I think I better understand the logic of that unevenly spread G3 pattern on Campag wheels.

One final question on the G3, would the wide spacing b/n the sequential triple sets of spokes be an issue in terms of rim strength? In other words, if that G3 laced wheel impacts a ridge on the ground at great speed at a point right in b/n two sets of triple spokes, would that more likely to dent the rim? Campag may have obvious design considerations to remedy this, but I am just thinking of this purely from a geometry point of view. Any comments on this?

Strid. Yeah I ditched the idea of powertap. It is not really overly useful since it is too heavy to use in a race or timetrial where watt monitoring comes in very handy.

I don't know if the 07 Eurus uses Al spokes, but apart from G3 they are becoming more and more like the 'wow I have those too' ksyriums. The Shamal would match the KMC X10SL that just went on my bike, and they are selling at a good price on 11speed. I haven't heard from dirtworks yet so I don't think they have arrived.

Thanks for all the info.

bobbyOCR said:

I'd rather have Italian than Japanese. I hate Shimano wheels, they need to revise their design. The current 105 wheels are an improvement though.

Here in lies the problem of thinking new wheels and thinking "I must have a factory wheel".

Rant....

The weight of the rim ---> spokes---->hub are what makes the difference in the speed of a wheel. Due to the small diameter of the hub, acceleration of the wheelset is not going to be affected greatly by running a 100g heavier hub. A reduced bearing resistence will do more than saving xxxg on a hub. Of course then a tyre and tube sit at the largest diameter, dont buy the lightest race tyre and tube and all the money spent on a bling wheelset is pretty much wasted.

A built up wheelset can be a heap cheaper, a little heavier overall but still run rims and spokes of equivalent/lighter weight to give a ride of almost identical performance.

People are welcome to burn their money and get reamed in the process (especially in Aust) for bike gear. But spending big does not make someone instantly faster, and in my opinion does not gain any cred in any way what so ever. There is a big diff between spending up for quality and spending up for [censored] factor.

Sorry for the rant. Not aimed at anyone. 😄

MOST of the wheels in the fulcrum range correspond to a wheel in the campy range. Racing 1 and eurus are very similar (racing one has Al spokes for a long time, 07 eurus may go that way, not sure, shamal has though). Both brands use 2:1/G3 for thier spoking on Al rims.

I'm guessing the much stiffer deep carbon rims get away with not G3 spoking as they don't wiggle back and forth as much. Low profile Al rims do.

Paulie-AU said:

Here in lies the problem of thinking new wheels and thinking "I must have a factory wheel".

Rant....

The weight of the rim ---> spokes---->hub are what makes the difference in the speed of a wheel. Due to the small diameter of the hub, acceleration of the wheelset is not going to be affected greatly by running a 100g heavier hub. A reduced bearing resistence will do more than saving xxxg on a hub. Of course then a tyre and tube sit at the largest diameter, dont buy the lightest race tyre and tube and all the money spent on a bling wheelset is pretty much wasted.

A built up wheelset can be a heap cheaper, a little heavier overall but still run rims and spokes of equivalent/lighter weight to give a ride of almost identical performance.

People are welcome to burn their money and get reamed in the process (especially in Aust) for bike gear. But spending big does not make someone instantly faster, and in my opinion does not gain any cred in any way what so ever. There is a big diff between spending up for quality and spending up for [censored] factor.

Sorry for the rant. Not aimed at anyone. 😄

Actually, the weight of the rim makes no difference to acceleration. This has been brought up many many times. A heavy rim does not 'decrease' rotational acceleration because the moment of inertia is too small for a human to detect. A heavy rim will detract from the overall weight. In fact, a heavy aero rim is faster than an uber light aero rim on the flat. the drag required to slow a 200g rim will theoretically be much less than the drag for a 600g rim (Alienator?, ScienceisCool?).

Hubs are important as well, hence the reasoon why I got DT hubs.

Spokes. mmm. I think Neutrons would outstrip the wide aluminium spokes of Eurus, racing1 and Ksyriums in a yaw of +/- 20 or anything past. They are like sails. The ovalised cross section of aerolites, CX-Ray and the Neutron spokes is appealing, as it would (theoretically) be more effective in a real world situation.

A couple downsides to Eurus is that they, like most campy rims, are a little larger than Mavics. This makes changing tubes a pain in the ass, especially when you want to do it quickly like puncturing during a group ride. Using a tire with a small cross section makes things worse because it is really easy to get part of the tube stuck under the bead.

They also use a slightly narrower machined braking area. This may require you to adjust your brake pads when chaning wheels. If the pads are not aligned then you can scrape away the upper portion of the stickers on the rim. The 2005 versions have a small step down from the machined braking surface to the lower part of the rim. This little step is sort of sharp. It can scrape you up when changing tires.

Lastly, the 2005 and earlier Eurus used steel spokes. The 2006 ones use AL ones. I am not sure about the 2007 version. You can get a pair from 11speed.com for about $650 USD. I don't know what shipping to Australia would cost or what duties you would have to pay.

Bro Deal said:

A couple downsides to Eurus is that they, like most campy rims, are a little larger than Mavics. This makes changing tubes a pain in the ass, especially when you want to do it quickly like puncturing during a group ride. Using a tire with a small cross section makes things worse because it is really easy to get part of the tube stuck under the bead.

They also use a slightly narrower machined braking area. This may require you to adjust your brake pads when chaning wheels. If the pads are not aligned then you can scrape away the upper portion of the stickers on the rim. The 2005 versions have a small step down from the machined braking surface to the lower part of the rim. This little step is sort of sharp. It can scrape you up when changing tires.

Lastly, the 2005 and earlier Eurus used steel spokes. The 2006 ones use AL ones. I am not sure about the 2007 version. You can get a pair from 11speed.com for about $650 USD. I don't know what shipping to Australia would cost or what duties you would have to pay.

I know that about the Eurus, I have decided against them. For a set of Eurus though, that equates to about $860 in current exchange rates, plus $65 for postage and $86 (10%) for customs I think. That comes to $1011. The cost of Eurus here is $1400 +\-

I like the look of Neutrons the best. DT are great (I'm surprising even myself) but a reputedly stiff wheelset with significantly less than 28/32 spokes may be a better option for the type of racing I do. I'll see what happens.

bobbyOCR said:

Actually, the weight of the rim makes no difference to acceleration. This has been brought up many many times. A heavy rim does not 'decrease' rotational acceleration because the moment of inertia is too small for a human to detect. A heavy rim will detract from the overall weight. In fact, a heavy aero rim is faster than an uber light aero rim on the flat. the drag required to slow a 200g rim will theoretically be much less than the drag for a 600g rim (Alienator?, ScienceisCool?).

Hmmm, fair enough. However if Physics determines that theoretically the drag required to slow a light rim is less than that of a heavy rim. The the same calculations would also show that theroretically less force is required to accelerate the lighter rim. Also I have a feeling that the calcs that determine this also assume that a wheel is a perfectly rigid object and do not take deformation of both the spokes and the rim into consideration. (Don't worry I dont want to work this out....I hate calculations)

If the moment of inertia is to small for a human to detect why then spend heaps more cash to save 50 - 100g off a wheelset. Seems kind of pointless 🙁 . Is the money better spent on bearings or something else? Additionally will a light rim with a heavy hub perform in the same way a heavy rim with a light hub will perform. The cost difference (forgetting carbon) between a light aero rim and "heavy" aero rim is SFA. The cost difference between a light hub and a "heavy" hub is pretty substantial. Seems like a waste to buy a light hub if a aero package is desired.

Is there a weight point for a bike that performance difference becomes undetectable to a human?

Sorry for the questions, I am looking for good value ways of making my roadie faster (I just have to loose weight to make me faster :o ) and trying to sort real solutions from rubbish solutions.

From what has been said, the accelerational properties of a light rim will become apparent at grades of over 10%, at any other time an aero rim will make more difference. The reason why we think a light rim=acceleration is simple, marketing. You have to look beyond what you are told about the wheel and form an educated opinion about what you know about the wheel.

I loved my DT wheels because they were not overly heavy for a race rim, they were Swiss 😄, They were easy to true, the hubs were the best (used by tour winner, or possible tour winner) and I knew exactly what was in them. 28 spokes though. Not great for junior tt.

Paulie-AU said:

Is there a weight point for a bike that performance difference becomes undetectable to a human?

Sorry for the questions, I am looking for good value ways of making my roadie faster (I just have to loose weight to make me faster :o ) and trying to sort real solutions from rubbish solutions.

No question is too dumb to be asked! (There are no stupid questions, only stupid people) :p

When you ride a flat stretch at approximately constant speed, weight is absolutely worthless to optimize on. You'll spend like 99% of your energy to overcome AIR resistance, which is purely a function of geometry (how you sit and so on), not your weight. Aerodynamics is king when it comes to not climbing.
However, when you start going uphill and your speed is lowered significantly, the equation tips over to the exact opposite. All your energy (or more truely power) (well, not everything, but realistically more like 80-90%) is used to climb. In this case, weight and speed are (to a very accurate approximation) each other's reciprocal. In effect, that means, that if your weight drops 5%, you'll go around 5% faster. In this case aerodynamics isn't king, but rather, weight is.
There is a thread called "Does weight really matter" a couple of pages back, you might want to take a look into it.

And I agree with BobbyOCR, that it is purely marketing that makes non racers worry about weight to such an extreme extend as many do today. If you get your bike from 10 kgs to 6.8 kg (min. UCI legal limit, and probably about 5% of your mass), you'll only gain about 1-2 km/h on a 5-10% climb (around 5% of your speed). Not a big deal, IMHO, your money are better spend on comfort and/or stiff components**.

All the thing about rotational mass is really bogus marketing. Perhaps you can feel a difference riding lighter wheels, but you're not going noticeably faster. And if you do, it's probably the Placebo effect (which in it self makes it okay). 🙂 If you do the math, you'll see that the energy spend on rotating the wheel is minute compared to the energy spend on accelerating the entire system (your body, your bike, your 1.5 kg water bottles and 500 g tools and tube in your back pocket and those little powerbars!).

**Unless you're going for the bling-factor, which is not to be neglected! 😄

Strid said:

No question is too dumb to be asked! (There are no stupid questions, only stupid people) :p

When you ride a flat stretch at approximately constant speed, weight is absolutely worthless to optimize on. You'll spend like 99% of your energy to overcome AIR resistance, which is purely a function of geometry (how you sit and so on), not your weight. Aerodynamics is king when it comes to not climbing.
However, when you start going uphill and your speed is lowered significantly, the equation tips over to the exact opposite. All your energy (or more truely power) (well, not everything, but realistically more like 80-90%) is used to climb. In this case, weight and speed are (to a very accurate approximation) each other's reciprocal. In effect, that means, that if your weight drops 5%, you'll go around 5% faster. In this case aerodynamics isn't king, but rather, weight is.
There is a thread called "Does weight really matter" a couple of pages back, you might want to take a look into it.

And I agree with BobbyOCR, that it is purely marketing that makes non racers worry about weight to such an extreme extend as many do today. If you get your bike from 10 kgs to 6.8 kg (min. UCI legal limit, and probably about 5% of your mass), you'll only gain about 1-2 km/h on a 5-10% climb (around 5% of your speed). Not a big deal, IMHO, your money are better spend on comfort and/or stiff components**.

All the thing about rotational mass is really bogus marketing. Perhaps you can feel a difference riding lighter wheels, but you're not going noticeably faster. And if you do, it's probably the Placebo effect (which in it self makes it okay). 🙂 If you do the math, you'll see that the energy spend on rotating the wheel is minute compared to the energy spend on accelerating the entire system (your body, your bike, your 1.5 kg water bottles and 500 g tools and tube in your back pocket and those little powerbars!).

**Unless you're going for the bling-factor, which is not to be neglected! 😄

I love the whole 'I want my bike under 6.8 because it will be faster'. You hear things like I want new handlebars which will save me 50g for a few hundred because its carbon and will be comfortable. Most pro bikes are in the 7s some in the 8 kilogram range. On the WW, one sponsored bike was a Merckx scandium which was around 8kg. Also, if you really want to weigh your bike, put your shoes on it. They are as much a part of the pedal as the pedal itself, they are rotating weight, you worry about their stiffness etc etc. You can quite easily drop 300g off their switching to shoes like Poggios (oh yeah 😄)

Paulie-AU said:

Hmmm, fair enough. However if Physics determines that theoretically the drag required to slow a light rim is less than that of a heavy rim. The the same calculations would also show that theroretically less force is required to accelerate the lighter rim. Also I have a feeling that the calcs that determine this also assume that a wheel is a perfectly rigid object and do not take deformation of both the spokes and the rim into consideration. (Don't worry I dont want to work this out....I hate calculations)

If the moment of inertia is to small for a human to detect why then spend heaps more cash to save 50 - 100g off a wheelset. Seems kind of pointless 🙁 . Is the money better spent on bearings or something else? Additionally will a light rim with a heavy hub perform in the same way a heavy rim with a light hub will perform. The cost difference (forgetting carbon) between a light aero rim and "heavy" aero rim is SFA. The cost difference between a light hub and a "heavy" hub is pretty substantial. Seems like a waste to buy a light hub if a aero package is desired.

Is there a weight point for a bike that performance difference becomes undetectable to a human?

Sorry for the questions, I am looking for good value ways of making my roadie faster (I just have to loose weight to make me faster :o ) and trying to sort real solutions from rubbish solutions.

Hmmm. Instead of a huge, long post I'll make some assertions. If anyone wants me to back them up, I'll write a big, long, geeky explanation.

The weight of your bike and any component such as the wheels is only a small part of the whole system. If your bike weighs 8 kg, you weigh 70 kg and all your gear weighs 2 kg then the system weighs 80 kg. Changing parts to get a 100 gram advantage makes a 0.1% change in mass of the system. Therefore, 100 grams makes almost no difference in climbing or acceleration. A 0.1% difference in climbing speed is pretty small. 19.98 vs 20.00 km/hr for example.

The difference in energy between a non-rotating part such as your frame and a rotating part such as your wheels is ~10%. This works out to less than 0.2% of your total energy. That's not a lot. Therefore a huge, 50% change in moment of inertia (i.e., heavier rims) would make a 0.1% change in your acceleration. If your riding partner took 10 seconds to come out of a corner and back up to speed, you would take an extra 1/100th of a second. This is why you can not feel the difference between heavy and light rims.

For the same size bike/rider and same aerodynamics, the heavier bike/rider has an advantage on flat roads. If both riders are moving along at 50 km/hr and both riders stop pedalling for one second, the lighter rider has to spend more energy to get back to 50 km/hr. This is true for all speeds. The light rider still has an advantage on the climbs.

John Swanson
www.bikephysics.com

ScienceIsCool said:

For the same size bike/rider and same aerodynamics, the heavier bike/rider has an advantage on flat roads. If both riders are moving along at 50 km/hr and both riders stop pedalling for one second, the lighter rider has to spend more energy to get back to 50 km/hr. This is true for all speeds. The light rider still has an advantage on the climbs.

Kool!

I'll strap on two bricks for tomorrow morning's club ride! I think I am on a roll here... Gotta make my bike heavier! Thanks for the highly unintuitive expert tip! 😄

sogood said:

Kool!

I'll strap on two bricks for tomorrow morning's club ride! I think I am on a roll here... Gotta make my bike heavier! Thanks for the highly unintuitive expert tip! 😄

One important caveat! It'll cost you more energy to get up to speed if you're heavier. So if you have to slow down a lot for things like corners, then it'll be better to be light. For example, a heavy track bike for the hour record would be ideal.

John Swanson
www.bikephysics.com

ScienceIsCool said:

One important caveat! It'll cost you more energy to get up to speed if you're heavier. So if you have to slow down a lot for things like corners, then it'll be better to be light. For example, a heavy track bike for the hour record would be ideal.

Dang... You've just ruined my day. :o

Lighter, heavier, lighter, heavier... Let's see where's the cross over of the two equations and the weight sweet spot.

ScienceIsCool said:

Hmmm. Instead of a huge, long post I'll make some assertions. If anyone wants me to back them up, I'll write a big, long, geeky explanation.

The weight of your bike and any component such as the wheels is only a small part of the whole system. If your bike weighs 8 kg, you weigh 70 kg and all your gear weighs 2 kg then the system weighs 80 kg. Changing parts to get a 100 gram advantage makes a 0.1% change in mass of the system. Therefore, 100 grams makes almost no difference in climbing or acceleration. A 0.1% difference in climbing speed is pretty small. 19.98 vs 20.00 km/hr for example.

The difference in energy between a non-rotating part such as your frame and a rotating part such as your wheels is ~10%. This works out to less than 0.2% of your total energy. That's not a lot. Therefore a huge, 50% change in moment of inertia (i.e., heavier rims) would make a 0.1% change in your acceleration. If your riding partner took 10 seconds to come out of a corner and back up to speed, you would take an extra 1/100th of a second. This is why you can not feel the difference between heavy and light rims.

For the same size bike/rider and same aerodynamics, the heavier bike/rider has an advantage on flat roads. If both riders are moving along at 50 km/hr and both riders stop pedalling for one second, the lighter rider has to spend more energy to get back to 50 km/hr. This is true for all speeds. The light rider still has an advantage on the climbs.

John Swanson
www.bikephysics.com

Agree with everything you've said, but with a proviso for racers. Your example of a 0.1% climbing speed advantage @ 20 kph would translate to 5 meters gained over a 15 minute climb. That could be a nice winning margin for a competitive climber.

Of course, many of us carry 1000-1500 gms of water or sports drinks on long rides, so just tossing the bottles at the bottom of the climb would yield a lot more advantage than a 100 gm lighter wheelset....if only we had the team car along side to hand us more drinks at the top 🙂

New developments. My R500 wheels have crappy seals. Very crappy seals. They sound terrible. (Fulcrum Racing 7s?)

Wheelcraft say they will replace the rims but they don't know which ones they are, they just get the finished wheels and ship them. They also said 'it'll be a few weeks' so I may be in for a wait.

Thanks for your help once again.

bobbyOCR said:

New developments. My R500 wheels have crappy seals. Very crappy seals. They sound terrible. (Fulcrum Racing 7s?)

Wheelcraft say they will replace the rims but they don't know which ones they are, they just get the finished wheels and ship them. They also said 'it'll be a few weeks' so I may be in for a wait.

Thanks for your help once again.

Good ol Dirtjerks. 🙁

Paulie-AU said:

Good ol Dirtjerks. 🙁

Yup 😠