[davman]

Hi

Whenever you read reviews of deep section carbon rims (say 38mm plus) the reviews quite often mention savings of such & such watts/power at an average speed of 40Km/h (as an example).

What if the average speed is significantly lower than 40Km/h, for example 27Km/h (approx 17mph) – are there still savings to be made from using deep section rims at these speeds or not?

Anyone have any examples or links to related information?

thanks

Simon Hume

 

 

Topic

[zeeridesbikes]

I replaced the stock dt swiss

I replaced the stock dt swiss 1800’s that came with my canyon for some 50mm aero wheels. They felt quicker and stiffer, but I’m sure I’d see similar benefits from the non aero version. Like most people I chose the 50’s because they look cool. 

[Simon E]

A wind tunnel session.

A wind tunnel session.

If you’ve sorted the big gains then wheels and tyres with low rolling resistance (tubeless or with latex tubes) if you haven’t done so already.

Some figures at https://www.shopforwatts.co.uk/blogs/news/watts-it-worth

An aero frame is a big expense for relatively small improvement. Tuning the engine will get you more gains than most hardware so consider a coach or a training plan.

[EddyBerckx]

PRSboy wrote:

I would be interested to see actual real-world evidence; on a given day, a rider could cycle a short loop with minimal traffic and junctions at a steady, say, 200 watts, on both sets, and see what the difference is in segment time.  Hardly perfect, but to me more meaningful than the nonsense trotted out in wheel company ‘white papers’.

 

GCN do those type of tests and they always show an advantage to aero wheels.  

[Welsh boy]

I didnt think for a minute

I didnt think for a minute that you were getting at me, I am just saying that for the type of riding I do now (heart condition, almost 60 years of age) there isnt any improvement, real or imaginary, for me buying deep section rims, I will get to the tea stop at the same time as my friend regardless of what I ride.  I may get there using slightly less energy on deep section wheels but it will not be noticable or make the difference to me winning a sprint at the end of the ride home.  I accept that these are factors for people who race but for most of us I dont think it makes a real difference.  I am not obsessed with weight (I know where i can shed 6 kg before i worry about a few hundred gramms on my wheels) but what i do like now is a bike which feels nice to ride and when i go out on my own i am not bothered if the ride takes me 2 hours or 1 hour 57 minutes.

[Nick T]

And what do you propose if

And what do you propose if your clothes are already tight and you are getting yourself as low as your body will comfortably allow, but you still want more aerodynamic advantage? 

[Dnnnnnn]

My understanding was that the

My understanding was that the aerodynamics became more important than weight at much lower speeds. Weight saving was most important on steep hills and when accelerating, whereas aero gains were greater at most speeds and at more constant speeds (i.e. when not rapidly accelerating).

I guess the balance between aero and weight will vary according to individual circumstances too – and whether either is very significant in the context of the OP’s level of riding I’d be a bit sceptical.

[PRSboy]

I would be interested to see

I would be interested to see actual real-world evidence; on a given day, a rider could cycle a short loop with minimal traffic and junctions at a steady, say, 200 watts, on both sets, and see what the difference is in segment time.  Hardly perfect, but to me more meaningful than the nonsense trotted out in wheel company ‘white papers’.

[the infamous grouse]

pablo wrote:

But let’s be honest the look cool that’s why we buy them. 

and depending on the rim, they can sound quite good as well.

one benefit of OP going to a shallower depth rim may be that it might have a wider rim section, improving comfort.

[pablo]

Never really felt that much

Never really felt that much difference on deep sections and a traditional style frame back to back rides on the same course were generally the same average within 0.5mph so is that wind or other factors. My aero bike and 303s on the other hand are noticeably faster on the same course. 

The reviews do make me laugh though when they state the numbers used. 

But let’s be honest the look cool that’s why we buy them. 

[Simon E]

Tom_77 wrote:

Tom_77 wrote:

Aero wheels should make you about 3% quicker, whatever speed you ride at.

3% quicker than what?

Mavic Open Pro with 32 round spokes (about the least aero rim you can buy) is often the baseline used by brands looking to make their products look more impressive. Even the same rim profile with 20 bladed spokes will improve on that.

Any aero gains made by wheels or frame are considerably smaller than changes to the rider. In descending order – position, clothing, headwear. If you really want to ride faster then wear tighter kit and get tucked in.

Weight differences have been repeatedly shown to very little difference to climbing speed, even on quite hilly terrain.

If you want some new wheels and have some money burning a hole in your wallet then go ahead and buy them. But if you aren’t racing then it’s not going to make any significant difference.

[Nick T]

You won’t get there any

You won’t get there any quicker but you will potentially use less energy to do so

[Nick T]

Scientifically, yes to both.

Scientifically, yes to both. Perceptibly, possibly not

[Mungecrundle]

Admit it. The primary
Admit it. The primary advantage of deep section rims on most of our bicycles is because they look good.

I’ll happily include myself in that group, but the truth is I still get a little frisson of adrenaline when I open the garage door and take the dustcover off a bicycle that to me looks feckin’ awesome.

[Anonymous]

The primary gain from having

The primary gain from having deep section wheels is that they look cool. Speed gains will be absolutely minimal for you.

[Cycloid]

The Weight vs aero benefits

The Weight vs aero benefits are not mutually exclusive.

My (Chinese) carbon wheels  which are 40mm front and 50mm rear weigh 1250g.

Light enough for climbing and on the rare occaision I get above 25mph I notice the difference, and they are more rigid.

[Author]

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