|Is a light wheel set worth it?||skippy pinfish|
Oct 2, 2002 7:24 PM
|I'm looking at a very light weight wheel set for the hills. I'm currently riding ksyriums, mine are just under 1700 grams. The wheel set I'm looking at is 1370 gram. Should I be able to notice the difference or am I just waisting money. These will not be used daily and I weigh 170 lbs.|
|re: Is a light wheel set worth it?||da cyclist|
Oct 3, 2002 6:21 AM
|Unless you're doing some serious extended climbs, aero will beat light every time. So unless this wheelset is going to be more aero than the ksyriums, I would save my money.|
|re: Is a light wheel set worth it?||JohnG|
Oct 3, 2002 7:14 AM
|Assuming you aren't compromising strength/stiffness TOO much you should feel the difference and like it. Keep in mind the K's are pretty stiff wheels so it's likely the new wheels will be a bit more flexy....... which might negate some of the weight differences. It probably depends on your riding style....... masher or spinner????
You might want to also do a search as this subject has been beat on a lot. Ultra light wheels are a compromise of weight/aero/stiffness.......... It's hard to get it all.
IMHO, unless you're willing to go with something like tubie 303's I'd stick with Ksyrium SL's or Campy Neutron/ERUS wheels. These are all reasonably light wheels and pretty strong and reliable.
|so, what you guys are trying to say is....||853|
Oct 3, 2002 7:26 AM
|That light weight wheels only help margionaly on a climb because of a constant speed or pace. Where as in a Crit with a constant draft and accelerations, light weight wheels would be more of a help?
|so, what you guys are trying to say is....||hirevR|
Oct 3, 2002 10:22 AM
|maybe i am being dumb but i thnk it would be just the opposite. On climbs, lightness is always a help because you are rarely going fast enough for aeros to even matter. now granted if you have flexy wheels because of force enacted upon them of because of sheer mass they are supporting, the transfer of energy will be less efficient and maybe cancel some of the lightweight benefit. but if you are a struggling climber they will be f great use.
in crits, where your aeros meaan the diff between being in the pele or OTB, the light wheels will not help you over the aerodynamics of a heavier, more aero dynamic wheel. And in this case, the force placced upon them druing a surge or final sprint will surely end in less efficient energy transfer hindering your efforts.
|so, what you guys are trying to say is....||Lactate Junkie|
Oct 3, 2002 11:16 AM
|Assuming the lightweight wheels are not so light or poorly made they flex or fold, then lightweight wheels are a plus for climbing. When you're climbing, aero doesn't make much difference, unless you can climb at 20mph. Light weight wheels are generally more beneficial in a crit than aero, because you are constantly having to accelerate out of corners and to cover surges and attacks. When you are in the field the aero advantage is minimal. If you go off the front in a break, then aero starts to move up the advantage scale, since in a break, there are fewer variations in speed and the corresponding accelerations and you have to spend more time in the wind pulling. Here are my personal recommendations:
If you are a breakaway style rider, get the lightest aero wheels you can safely use, and get the best of both worlds. But generally lean toward aero at a reasonable expense of weight
If you are a field sprinter and are not going to see clean air until the last 200m, get the lighest stiffest wheels you can find, and forget about aero.
If it's a road race and basically flat, go aero.
If it is a very hilly road race, go light.
If you are not a racer and ride mostly alone, go aero
All in all, the newer carbon aero wheels like zipp 303's, 404's and others are getting so light that you can have the best of all worlds if you go for the ultimate. If you are sticking with aluminum rims then the above points are good guidelines IMHO.
|so, what you guys are trying to say is....||da cyclist|
Oct 3, 2002 9:07 PM
|Lightweight isn't necessarily better for a climb (regardless of whether or not you can climb at 20mph). http://www.analyticcycling.com/WheelsClimb_Page.html. Aero benefits typically kick in at about 13 mph. I don't think I've ever gone that slow in a rr before.
In order for the ligher wheelset to be faster, you have to basically have a 13% slope for 5km. Granted in this case, the lighter wheelset is still a conventional wheel, but if you play with the model, you'll find that lightweight doesn't make up for aero unless there is a BIG weight difference and a long/steep climb.
Just FYI, the specialized tri-spokes that they're using in the model are just about the most aero wheel ever made. I believe the design was actually bought by Hed or Lew.
If you look at the case for a criterium corner, again the aero wins, but not by much. Anyways, analyticcycling.com has alot of models that you can play around with for this kind of stuff. Sometimes the results are not very intuitive.
|so, what you guys are trying to say is....||Lactate Junkie|
Oct 4, 2002 11:11 AM
|It really depends on weights and the aerodynamic qualities of the wheels. The analytic cycling takes a very aero wheel (which is rarely used for road racing for a number of reasons) and a not so light wheel to make the comparison. Even still, take a LEW KOM or a Zipp 303 and plug in the number in place of the "standard wheel" and you will see that the lighter wheel is significantly faster. As well, if you live somewhere there are real climbs it isn't unusual to be climbing at less than 10mph for extended periods of time, even in 1-2 packs.
In the case of a criterium corner, AC is also comparing a very aero wheel to a not so light wheel in an open environment, not in a pack. Once you are sitting in a pack there is little or no advantage to aero wheels. Again, change the wheels to a more normal comparison and you will see that the light wheel again has an advantage in acceleration.
|Stiffness according to Jobst Brandt||Spoiler|
Oct 3, 2002 8:59 PM
|"Although it is worth analyzing, stiffness is not an important consideration in wheel design. Components and spoke patterns should be selected for strength and durability. A wheel that is strong enough to withstand the loads of it's intended use is also stiff enough. Stiffness if often put forth as an excuse for peculiar designs. 'It makes the wheel stiffer,' is often claimed in defense of an unconventional design. However, some of the world's strongest cyclists have ridden the kilometer time trial on 24-spoke small-flange wheels with light-weight rims. Although this even requires precise control and enormous starting torque that exceeds nearly all stiffness and strength demands of other cycling , these racing wheels are adequately designed for their specific use. jhey lack the long-term durability of road wheels, but they are stiff enough."|
|I remember reading some technical paper...||Wayne|
Oct 4, 2002 7:10 AM
|on wheel design and it basically agreed with that statement. In fact, it said unless your wheels flex so much that they rub the brake pads, wheel stiffness is irrelevant to performance.|
|I remember reading some technical paper...||853|
Oct 4, 2002 8:21 AM
|My logic says, power flexing a wheel could have been better used to transmit power to the ground. Of course, thos are just my thoughts.|
|It does seem...||Wayne|
Oct 4, 2002 8:59 AM
|counter-intuitive. I was never any good at physics and i'm certainly not an engineer. Maybe it's possible that flexing wheels in no way detracts from forward speed? Or maybe the flex is just inconsequential in detracting from forward speed?|
|Where does the energy go?||53x11|
Oct 4, 2002 2:26 PM
|Where does the energy end up in a flexed wheel? Laws of thermodynamics states that energy is conserved in a system (no net change of energy in the system plus the surroundings will occur). I'm no physicist or engineer, but it seems to me, when you temporary flex a wheel you "load" it like a spring compression. When the wheel "unloads" that energy would then be transferred to the road. A slight loss in energy would occur and be given off as heat in the area of flex (just like any piece of metal you flex a bunch of times). Still hard for me to believe riding noodles is better than something solid. I'm just guessing too!|
Oct 6, 2002 5:19 PM
|The problem with flexy wheels is the poor handling and the obviously disconcerting feeling that your energy is being sucked up by the flex. In practice, you'd have to have some pretty hot spokes to waste any significant amount of energy.|| |