2% Weight Reduction (Wheels)

BBB wrote:

BBB wrote:

he nonsense about lighter wheels making a big difference will be repeated forever regardless of how much independent evidence to the contrary is available. 

It’s been the same with narrower tyres or higher pressure being faster, stiffer frames being more “efficient”, road pedals transfering power “more effectively” etc etc… All based on errr… feel firm beliefs and scraps of often valid but incomplete or irrelevant data taken out of a wider context. 

 

P.S. I must say though the Earth felt so flat when I was cycling to work this morning.

Is this aimed at me? I was merely pointing out that lighter wheels (half a kg more) are basically more fun to ride. Which pisses some of the old school off I admit.

Cycling should not be fun.

Just the extra fun and
Just the extra fun and placebo factor of riding lighter wheels (half a kg min I’d say) is enough to make it worthwhile.

Zippier and easier acceleration from the billion lights and junctions on my commute means a better riding experience for me personally.

fukawitribe wrote:

madcarew wrote:

fukawitribe wrote:

Yeah and nah – can’t say i’ve seen a site that actually bases their figures on the acceleration due to pedalling, generally seem to be an average power / VAM calculation which gets more simplistic the higher the grade/lower the cadence ; then again, would the better analysis come up with anything that makes a radical difference ?… almost certainly not.

Several studies have been done on precisely this, and found that the effects of weight at the rim compared to weight of the whole bike are negligible. Remember, if you are accelerating the rim, you are accelerating the entire bike and rider, so your numbers come back to similar to what John S is discussing above. 

Yep, agree with most of that – my issue was whether it could be detectable and that the sites don’t take into account the acceleration of the bike/rider with the pedal stroke, just overall speed etc.

The rim accelerates at the same rate as the bike (and mostly the rider) and as such the rim weight iseffectively  simply bike weight. So relative to a bike with 160g lighter wheels, all other accelerations taken into account, the difference of a 160gm lighter wheel against a 75kg cyclist + bike is less than .2%, which even supposing the acceleration part of the pedal stroke is 500W on an average over the stroke of 250W, .2% difference is only 1 W, which all tests shows is undetectable to even a highly trained rider. Sad to believe (I too held dear the idea that rim weight was more important than bike weight) but the extra weight of 160gm, whether at rim or at drink bottle is undetectable, which addresses the OP’s question.

fukawitribe wrote:

Yeah and nah – can’t say i’ve seen a site that actually bases their figures on the acceleration due to pedalling, generally seem to be an average power / VAM calculation which gets more simplistic the higher the grade/lower the cadence ; then again, would the better analysis come up with anything that makes a radical difference ?… almost certainly not.

Several studies have been done on precisely this, and found that the effects of weight at the rim compared to weight of the whole bike are negligible. Remember, if you are accelerating the rim, you are accelerating the entire bike and rider, so your numbers come back to similar to what John S is discussing above. 

NorthEastJimmy wrote:

Thank you all for your responses, not sure I’m any futher ahead in making a decision but still fascinating to take all the various opinions into consideration.

I guess I always thought my current wheelset to be very average (but with decent hubs) although I can’t pin point anything wrong with them. 

In terms of weight, I’m 75kg and I’ve lost about 10kg in the last year and since then I do notice more  minor amounts of weight difference on the bike, but yes I would probably never notice anything under 400g from one ride to another.

I did look at ‘Light Bicycle’ but by the time I added everything I would want to make the wheelset of choice, it was close to £750 and before shipping.

I do love the look of deep carbon rims, like a lot of people, but didn’t want to spend that amount of money on a cosmetic upgrade.  Some of the comments above have swayed me more to consider up to 50mm though and those Hunt 50’s do look amazing! 

I do quite a bit of climbing and do tend to climb out of the saddle more compared to other riders, so I’m sure rim flex is an issue for my style of riding.  However, I’m not that in tune with the bikes ive ridden to notice stuff like that…would make a terrible product reviewer.

 

I had some RR521 32mm deep wheels made up with DT350 hubs I had taken off some damaged carbon wheels.  They are slightly wider internal rim so make 25mm tyres widen to 28mm, making the rim and tyre alot more flush aiding aero benefits a little.  I bling’d the wheels with red nipples 😀

… adding to that.. get a

… adding to that.. get a set of 46mm deep rims from light bicycle for £300 delivered, use the dt350 hubs (matching the hole count!) you already have and spend £125 taking the bits to your local bike shop to build you the wheels up with spokes and manpower. 

Best of all worlds.. lighter, wider, cheaper and faster!

It depends where the 160g is

It depends where the 160g is located. On the frame (or on you!) you most probably wouldn’t notice. However, the further out on the wheels, the more you might notice it. At the hubs, probably not. At the rims, maybe. In particular – depending how sensitive you are to different levels of personal fitness/performance, tyre pressures/bike performance, road and wind conditions  – you might notice 160g (80g per wheel) out at the rims in terms of acceleration but you’d have to be pretty in tune with your body/bike! I changed tyres and tubes once and saved about 150g per wheel and that was defninitely noticeable, escpecially on long steady climbs where each push on the pedals is an effort and a mini ‘accleration’ – here is where you *might* notice a small decrease in rotating weight (or just flat-out accelerating!).

I also wouldn’t dismiss deep section ‘aero’ rims due to cross-wind issues. Yes, if you are going 50/60mm deep and above then you definitely may feel a little more buffeting in cross winds but i have some 38mm (and some 50’s) deep aero profile carbon rims and they are much more predictable in windy conditions than the 30/32mm deep non-aero aluminium rims they replaced, particularly in front-quarter cross winds or into a headwind. Due to the aerofoil profile they remain much more ‘planted’ when the wind around the wheels switches from side to front e.g. as you pass a gap in a hedge, or as a large vehicle passes you. Yes, with a direct sidewind you feel a larger force pushing due to the higher surface area but it is much less ‘snatchy’ when the direction changes and it is rare that you get a continuous sidewind unless you are cycling along a long straight exposed road, e.g. along a coast. With my old wheels I guess the air passing them was more turbulent due to the ‘sharp’ edges on the inside of the rim and with changes in the angle of the wind they could ‘flick’ noticeably  leaving you feeling somewhat wobbly in gusty conditions! The deeper aero rims feel like a knife through butter in many ways, most especially into a big headwind. Maybe some of this is phsycological though?

At the end of the day a new set of wheels, even if only 160g lighter (maybe more with suitable tyre/tube choices?), might give you nothing more than a phsycological ‘boost’ but that could be all you need? If you start cycling quicker for a reason (whether equipment or phsycological), that will improve your general fitness level, which in itself will allow you to cycle quicker again! Its a win-win!