Just how much difference does lighter wheels make?

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Just how much difference does lighter wheels make?

Postby thecaptn » Mon Jun 17, 2013 9:52 pm

Hi All,
I'm sure this has been done to death but here go's...

Just how much difference do light wheels make over stock $200ish racing wheels and are they an absolute compromise on strength? For instance how do Fulcrum 5 or 7 compare to Fulcrum 1 or 0? A set of Fulcrum 7 will cost as little as $160 del, What does the extra $700-$800 buy you other than a saving of a couple of hundred grams?

I've never had anything but mid range bikes and would appreciate some opinions,

Thanks,
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by BNA » Mon Jun 17, 2013 10:09 pm

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Re: Just how much difference does lighter wheels make?

Postby Bob_TAS » Mon Jun 17, 2013 10:09 pm

Reduced weight and improved quality are the two factors that spring to mind, though there can be compromise i.e. strength or flex.

There are plenty more qualified to answer, but I just wanted to let you know about my experience with Fulcrum Racing 7s.

Not only did I get dramatically ripped off by a shop in Port Melbourne (was more naive back then), but the seams in the rims left me immediately wishing that I had spent the same amount of money on something better. The hubs however, are very good.

IMHO if you like Fulcrum, don't go with the 7s.
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Re: Just how much difference does lighter wheels make?

Postby trailgumby » Mon Jun 17, 2013 10:21 pm

Lighter weight means improved performance, especially when it's rotating mass at the circumference. Light wheels spin up easier and should roll better too if engineered well.

However, they can be weaker or more flexy, most noticeable as you try to change direction, which influences cornering confidence. They often have weight limits. For example, I'm looking at 29er wheel options and some Stans NoTubes rims have a 190lb rider weight limit. Kitted up with my camelbak, I'm right on that number, so I won't be purchasing that model.

Mind you, cheap wheels can just as easily be weak and flexy too, as well as very heavy. Light. Strong. Cheap. Choose any two.
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Re: Just how much difference does lighter wheels make?

Postby Philipthelam » Mon Jun 17, 2013 10:38 pm

I recall reading an experiment done by someone where they climbed the alpe d'huez four times with different bike setups. In one of the tests they had around 2 litres of water in the tyres and he was only slower by 2 minutes or so. You can probably find the website if you do a google search. If you put this in perspective, 2kg in the tyres is a lot of extra weight. Fulcrum racing 7s weigh 1849 grams and fulcrum 1 weigh 1485 grams. This is less than 400g difference and not all the the weight loss is from the rims, a lot is from the hub and spokes as well. So I don't think lighter wheels make that much difference unless you are comparing super light wheels with 3kg+ wheels.
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Re: Just how much difference does lighter wheels make?

Postby thecaptn » Mon Jun 17, 2013 10:44 pm

trailgumby wrote:For example, I'm looking at 29er wheel options and some Stans NoTubes rims have a 190lb rider weight limit.

Light. Strong. Cheap. Choose any two.

My 29er has Stans NoTubes rims on it and I'm wayyyy heavier than that. I hope they're not the same model :shock:


"Light. Strong. Cheap. Choose any two." This is it in a nut shell.
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Re: Just how much difference does lighter wheels make?

Postby queequeg » Tue Jun 18, 2013 2:45 pm

thecaptn wrote:
trailgumby wrote:For example, I'm looking at 29er wheel options and some Stans NoTubes rims have a 190lb rider weight limit.

Light. Strong. Cheap. Choose any two.

My 29er has Stans NoTubes rims on it and I'm wayyyy heavier than that. I hope they're not the same model :shock:


"Light. Strong. Cheap. Choose any two." This is it in a nut shell.


I am pretty sure that is a "per wheel" limit, so unless you have one on a Unicycle, you can safely say the total weight is somewhere between 190 and 380lbs, as your weight is distributed over both wheels.
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Re: Just how much difference does lighter wheels make?

Postby AndyRevill » Tue Jun 18, 2013 4:10 pm

Philipthelam wrote:I recall reading an experiment done by someone where they climbed the alpe d'huez four times with different bike setups. In one of the tests they had around 2 litres of water in the tyres and he was only slower by 2 minutes or so. You can probably find the website if you do a google search. If you put this in perspective, 2kg in the tyres is a lot of extra weight. Fulcrum racing 7s weigh 1849 grams and fulcrum 1 weigh 1485 grams. This is less than 400g difference and not all the the weight loss is from the rims, a lot is from the hub and spokes as well. So I don't think lighter wheels make that much difference unless you are comparing super light wheels with 3kg+ wheels.


http://www.training4cyclists.com/how-mu ... lpe-dhuez/

:D
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Re: Just how much difference does lighter wheels make?

Postby NhiTrac » Tue Jun 18, 2013 4:57 pm

I went from a 41mm 1.8kg wheels to an under 30mm 1.4kg and felt a big difference in spin up. Of course I don't feel it anymore as I'm used to it but its definitely there. When they're up to cruising speed however, not much difference for the average non-competing rider. FYI it was SOUL 4.0S to Fulcrum Zeros.

Other benefits of a "higher end" wheel:

- higher quality material used
- lighter
- stiffer
- stays true a lot longer

Each of the above will directly affect the overall quality of your ride and experience which possibly results in less fustrutation and more enjoyment when you ride, which as the main reason I upgraded.
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Re: Just how much difference does lighter wheels make?

Postby toolonglegs » Tue Jun 18, 2013 5:09 pm

Disc wheels are double the weight of climbing wheels... i know what I would rather have in a tt... horses for courses.
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Re: Just how much difference does lighter wheels make?

Postby biker jk » Tue Jun 18, 2013 5:11 pm

If you do a lot of climbing then a lighter wheel will shave a little time. If the lower weight is due to the rims then the wheel will be easier to accelerate but once up to speed there is little, if any, advantage. However, a lighter rim will be weaker and possibly not as stiff. The strength of a rim is a function of its depth and width.
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Re: Just how much difference does lighter wheels make?

Postby pawnii » Tue Jun 18, 2013 11:00 pm

you can get a set of wheels that's 1kg, 50mm profile rims and very stiff....if you have the money.
so light doesn't necessarily mean weak.
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Re: Just how much difference does lighter wheels make?

Postby NhiTrac » Wed Jun 19, 2013 7:33 am

pawnii wrote:you can get a set of wheels that's 1kg, 50mm profile rims and very stiff....if you have the money.
so light doesn't necessarily mean weak.


What's that rule?

Strong, light, cheap. Choose only two.
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Re: Just how much difference does lighter wheels make?

Postby pawnii » Wed Jun 19, 2013 8:19 am

yeah i'd agree with that.
I'd invest in good wheels before anything else.

Braking quality on full carbon rims also needs to be considered.
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Re: Just how much difference does lighter wheels make?

Postby simonn » Wed Jun 19, 2013 10:27 am

I can feel a big difference between my pro-lite braccios (~1500g) and 32h DT Swiss RR585 (585g each rims)/Miche Racing Box hubs on the same bike (Van Nicholas Euros). I live in the Northern Beaches, Sydney so lots of climbing.

I've been doing 200km hilly randonees with an average speed of > 25-26km/h on my roadie which used to have Ksyrium Equips (~1500g) for over a year, maybe longer. Did one last sat on my disc brake CX with ~2.2kg wheels (not including 28mm gatorskins) (AT) ~21km/h. There was ~35km of dirt, including the main descent which I could not hammer down, but that was definitely not the whole story, certainly not 4-5km/h less of a story. Climbs which I have done many times were definitely slower. It was just much harder/slower work with the extra weight. Then again I have done flat-ish (as far as you can in the Northern Beaches, Sydney) group rides on the same bike and kept up with the carbon vunder-bikes (albeit with significantly less time on the front).
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Re: Just how much difference does lighter wheels make?

Postby winstonw » Wed Jun 19, 2013 10:43 am

Extra weight generally buys you extra km's. A mate and another guy have destroyed two sets of Fulcrum 3s in the last 3 months.
Neither had more than 25,000km on them. If you are happy with lower k's, then no problem with light weight.
If you want 40,000+k's, and not be concerned about riding rougher roads, then go a wheelset around 1600-1900g and a minimum 24/28 spokes.
And naturally, the heavier you are, the more longevity is effected.

You might hear on BNA of heavy guys (>85kg) riding light wheels (<1600g), and not having an issue, but if they don't clarify how many k's and on what surfaces, it doesn't mean much.
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Re: Just how much difference does lighter wheels make?

Postby ball bearing » Wed Jun 19, 2013 10:44 am

Each push of the pedal causes an acceleration. Riding consists of many thousands of mini accelerations. Reducing the weight of the wheels a bit translates into a fraction less energy being required for each of those accelerations. It is not just about speed. For myself, it is more about efficiency and energy conservation as where I live it is all climbing and descending when riding my road bike.
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Re: Just how much difference does lighter wheels make?

Postby Angus » Wed Jun 19, 2013 12:09 pm

Do you notice a difference? - Definitely. I'm sure there is some placebo effect as well but there really is an actual difference.

I am 95 kgs (down from 110kgs!) and will likely plateau around mid to high 80's so will always be hard on wheels/tyres.

I have a set of DA C24s which are around the 1400-1450g mark, and a set of ambrosio/ultegra hub/32 spoke wheels around the 1750-1800g mark. There is a noticeable difference between these wheels. The ambrosios I use for 'everyday use', the C24s for mountain-goat rides and fast pack rides where you are constantly accelerating.

As per Winston above, the lifespan of the C24s for me will be less than the featherweight guy at 65kgs wringing wet for the same riding conditions. The C24s are strong and light (and not cheap), but lifespan is another factor in there influenced by your weight and general riding conditions.

I use the daily wheels to save the C24s a bit, but also it feels like a little turbo-boost when you do actually use them. So yes there is a difference!
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Re: Just how much difference does lighter wheels make?

Postby trailgumby » Wed Jun 19, 2013 12:30 pm

queequeg wrote:
thecaptn wrote:
trailgumby wrote:For example, I'm looking at 29er wheel options and some Stans NoTubes rims have a 190lb rider weight limit.

Light. Strong. Cheap. Choose any two.

My 29er has Stans NoTubes rims on it and I'm wayyyy heavier than that. I hope they're not the same model :shock:


"Light. Strong. Cheap. Choose any two." This is it in a nut shell.


I am pretty sure that is a "per wheel" limit.

I'm pretty sure it ain't. ;) Where on earth did you get that from? :D

From memory it was Stan's Crest rims with the 190lb limit. Stan's Arch are rated to a 110kg rider weight limit.
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Re: Just how much difference does lighter wheels make?

Postby vosadrian » Wed Jun 19, 2013 12:46 pm

I got my bike with older Mavic Aksiums at around 2000g plus 100g tubes (Race 28s) and 200g tyres (GP4000S). I recently got some Duraace C24s at around 1400g plus 67g tubes (Maxis Ultra light) and 200g tyres (GP4000S). So saved almost 700g which I think is sizable in terms of wheel weight saving.

I can really feel the difference in acceleration. The bike feels a lot lighter to ride because it responds more quickly. Also the new wheels feel stiffer and it really transformed the feel of the bike to feel like a new bike.

In terms of speed increases... I am not really seeing anything that I could quantify. Maybe there is a few seconds on an 8 minute climb... but I have not beaten any of my PRs by 10+ seconds or anything like that. Recently I had a tyre issue and swapped to my old wheels before going out for a regular run I do. Average speeds and segment times were all about the same. Any benefits of lighter wheels are less than my ride to ride variation in times.... but the bike felt like a MTB to ride with the older wheels. Loss in acceleration was noticed and it just felt looser... but these things make little difference once you are rolling on a 50km ride with little interruptions to stop you.

On the argument of light wheels accelerating every time you push the pedal.... they also decelerate quicker.... so although a light wheel may spin to a slightly higher speed as you push down, it will decelerate to a lower speed when the power is off, and for the same net energy input, the efficiency/speed will be the same.

I am happy with my purchase decision for the new wheels. I like them just for the feel they provide. Kind of like someone buying a low powered sports car for the feel of it more than the outright pace it provides.
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Re: Just how much difference does lighter wheels make?

Postby KL. » Wed Jun 19, 2013 6:17 pm

Hi thecaptn, light weight combined aerodynamics is best, but there are exceptions where higher mass assists with high speed flat/flatish rides such as TT's (no climbs), due to inertia/momentum.

A weight of about 1500g or less is good, and the more aero the better but not at the expense of the rim depths being to deep where riding in crosswinds dramatically affects bike balance (between 27mm and 50mm seem to be good rim depths, depending on weight, and desired wheel stiffness). Although, rim depths >50mm appear to be ok when wider 23mm or 24mm rims are used.

The consensus is that wider rims give more comfort (lower tyre pressure can be used, ie 105 -> 95/100), better cornering (tire has more round shape - almost tubular), stiffer, better handling in cross winds (wind from side), little higher weight. That is 50Dx23W or 60Dx24W Tubs/CL are much better in wind than 50Dx20W or 60Dx20W Tubs/CL.

So, 50Dx23W or 60Dx24W Tubs/CL might be the best weight (about 1500g or less) and aero wheelset combinations for all cycling conditions, but 27D to 40D is also very good and exist in alloy rims :=)

Very light wheelsets (< 1300g) are really only needed for lots of climbing or crit circuits with many corners where fast acceleration of out the corners is constantly required. A very light wheel that is not stiff is not good either, especially re descending or sprinting :=)

Also, good, low friction, stiff hubs are important :=)

thanks KL :=)
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Re: Just how much difference does lighter wheels make?

Postby Philipthelam » Wed Jun 19, 2013 7:56 pm

ball bearing wrote:Each push of the pedal causes an acceleration. Riding consists of many thousands of mini accelerations. Reducing the weight of the wheels a bit translates into a fraction less energy being required for each of those accelerations. It is not just about speed. For myself, it is more about efficiency and energy conservation as where I live it is all climbing and descending when riding my road bike.


What about heavier wheels having more inertia? Would that cancel out the energy lost in needing to accelerate heavier wheels?


The issue, I think, with most first hand experiences is that lighter wheels are often more expensive, higher end wheelsets. So while the lighter wheel may feel better than a heavier wheel it is not the result of weight but a variety of other factors such as stiffness, aerodynamics, better bearings etc.
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Re: Just how much difference does lighter wheels make?

Postby ball bearing » Wed Jun 19, 2013 7:59 pm

Philipthelam wrote:
ball bearing wrote:Each push of the pedal causes an acceleration. Riding consists of many thousands of mini accelerations. Reducing the weight of the wheels a bit translates into a fraction less energy being required for each of those accelerations. It is not just about speed. For myself, it is more about efficiency and energy conservation as where I live it is all climbing and descending when riding my road bike.


What about heavier wheels having more inertia? Would that cancel out the energy lost in needing to accelerate heavier wheels?

Uphill I doubt that inertia is more beneficial than less rotating mass. I know which wheels I will choose to ride on the hills if the choice is between 2000G or 1400G. My legs tell me all I need to know.
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Re: Just how much difference does lighter wheels make?

Postby Philipthelam » Wed Jun 19, 2013 8:17 pm

Here is an interesting read http://velonews.competitor.com/2012/06/ ... ter_223209
Lennard Zinn wrote:The bike always has to accelerate at least once to get up to speed, and that will take more energy to do if the added mass is at the rim than if it has instead been added to the frame. One question is whether the extra energy required for this initial acceleration is trivial and can be ignored or not. After that, even if the rider speeds up and slows down the same way on each bike without using the brakes, it will not matter where the extra weight is located, at least in the “ideal, frictionless universe” used in elementary physics calculations of motion. If the rider stops pedaling, even on a climb, he will be carried further up the hill by the flywheel effect of the heavier rims than he will be on the bike with weight added to the frame. Then when he starts pedaling again, he will end up at the same point in the same amount of time on either bike. This is the principle that Ondrej Sosenka depended upon when he set the hour record with heavy rims; he reasoned that the heavy rims would carry him along and keep the speed more constant as he went through periods of weakness and strength. It seemed to work for him; I’m not going to argue with that result.


You have to wonder how much a wheel actually decelerates while pedalling or rather how much a wheel needs to be accelerated while pedalling and also how much more a lighter rim decelerates more than a heavier rim. Last of all you have to wonder whether these small differences ... actually make a significant difference or if the increase in performance based on weight alone is negligable. Physics is fun :D

I think this quote sums it up pretty well
Lennard Zinn wrote: If you’re somebody who replaces the steel bolts holding your bottle cages on with aluminum or carbon bolts, then by all means get the low-inertia wheels — they will be faster.
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Re: Just how much difference does lighter wheels make?

Postby MREJ » Wed Jun 19, 2013 8:31 pm

+1 re light wheels for climbing or tight crit circuits with lots of accelerations out of corners.
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Re: Just how much difference does lighter wheels make?

Postby Alex Simmons/RST » Thu Jun 20, 2013 1:00 pm

MREJ wrote:+1 re light wheels for climbing or tight crit circuits with lots of accelerations out of corners.

For crits, better wheel aerodynamics is more important than wheel/rim weight for accelerations and speed (or energy saving for same accelerations/speed), but there are obviously several other considerations as well, such as steering and handling characteristics, and robustness (putting cost to one side) - e.g. some aero wheels don't handle as well when under corning pressure or you have unsuitable wind conditions, and some are simply not suitable at all (you won't race a disk in a crit for instance). Of course you can have both light and aero if you pay for it.

What people feel with lighter rims is more likely to be different handling characteristics than an acceleration difference (which is pretty small).

Any variations in speed through a pedal stroke are very small (there is a lot of inertia in the bike+rider system) such that the wattage difference wrt to the micro accelerations are less than a handful of milliwatts. I've posted data on that before, but maybe not here, I can't recall off top of my head. Speed variations are larger when climbing uphill than on flats (as you'd expect due to lower inertial load) but are still a very small order effect.

And yes, a wheel with a higher rotational inertia doesn't slow down as quickly either but Sosenka was a doper. That had much more to do with his performance than his wheels.
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