Wheels on a budget: deeper, heavier aero or shallow and lighter?

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Aero or lightweight

Aero, you won't feel the weight
13
45%
Light and shallow, you'll feel the extra 300g
16
55%
 
Total votes: 29

nickcube
Posts: 142
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by nickcube

About to buy myself a caad12 and I plan on quickly dropping the wheels on it(mavic aksium, 1880g) for something a bit nicer. It'll be a "do it all" wheel set, I plan on doing relatively flat rides, kind of lumpy, but I plan on doing some climbing too when I go away and also doing a bunch of criterium races.

With my budget of $600aud(around 420 euro), I guess I've narrowed it down to either the 40mm deep prolite wheels on wiggle, which are around 1800g or something similar to shimano rs81 c24s, which are around 1500g. Is it worth going for a deeper section wheel and not worrying about the 300g or is the aero benefit big enough to justify the prolites considering most of my riding will be on slightly lumpy terrain and in crits?

To go for aero or for weight, that is the question and if anyone has any suggestions as to what other wheels are out there I'd love t hear them, cheers!

Marin
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Location: Vienna Austria

by Marin

35 to 45mm is deep enough, but you should aim for under 1600g imo.

For more than 30mm depth you don't use alloy rims because they'll be too heavy and V-shaped, so the aero is questionable and the crosswind handling will suck.

So if the bugdet is fixed and it's alloy, go shallow.

If you can spend a bit more, go 34-45mmx25 wide from Light Bicycle or Farsports.

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Asteroid
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Joined: Tue Jul 26, 2016 8:43 pm
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by Asteroid

Those RS81 C24's you mention are fantastic wheels. I tooled around with a pair outfitted on a friend's bike, and could not tell the difference from my DA C24's. Whisper quiet, stiff, and smooth. It seems he paid less than 420 euro shipped from the UK to the states.

The wheels on my winter bike weigh in at about 1850g. I can tell the difference on climbs and initial accelleration.
Oldbie

nickcube
Posts: 142
Joined: Mon Feb 23, 2015 8:01 am
Location: Melbin, 'Straya

by nickcube

Good points guys, thanks. Sounds like I have some thinking to do about the chinese wheels now, I kind of wrote them off due to the amount of problems with braking on carbon and since these will be everyday wheels I'd rather not have the hassle. Are the quality of the chimese rims really up there now?? Thanks

McGilli
Posts: 373
Joined: Sun Jun 07, 2015 6:57 pm

by McGilli

nick cube wrote:...about the chinese wheels now, I kind of wrote them off due to the amount of problems with braking on carbon and since these will be everyday wheels I'd rather not have the hassle. Are the quality of the chimese rims really up there now?? Thanks


I'm just saying - that by your comment - I think you'll always have that doubt in your mind. You don't want doubts in your mind that make you 'think twice' about braking hard when you really need to.

Anyways - I've recently switched out all my deep carbon wheels (48mm/60mm/70mm/88mm) to shallow alloy (24mm) for weight reasons. I've done Time Trials competitively for 3 years so I was really into the aero aspect of wheels and gear. I've slowed down my 'normal' riding this past year and trust me - if you're not averaging at least 40kmh on your rides, go for lighter, shallower wheels. A good engine trumps marginal aero gains any day! Good luck!

bm0p700f
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by bm0p700f

Aero trumps weight. 35 to 45mm deep clincher are not so much lighter than 50mm deep rimmed wheels that the weighg diiference ammounts to anything.

The aero difference does add up to something not much but something real.

Go for wide rims as well.

The physics is clear on this. Aero effects work at 30 kph too. Time over a course is inversely proportional to the power used cubed (ignoring rollining resistance which does not chane tye result much).
Time saved by loosing 200g is close to zero. So i trust what the previous poster feels is not what the maths says. Aerodynamics is so well tried and tested that the maths can be believed over percieved experience.

Some chinese rims are as good as zipps for braking.

ChiZ01
Posts: 477
Joined: Wed Jan 01, 2014 6:20 pm

by ChiZ01

for everyday wheelset, a u-shaped 38mm chinese rim is hard to beat, pair it with dt240 or white ind hubs and you are golden. If the rim breaks you can easily replace it for less than $200. Compared to Enve where the rim cost like $900. It only takes 1 pothole to brake ur rim

bm0p700f
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by bm0p700f

wrong a u shaped 50mm rim best again aero trumps weight every time. going shallower does not improve performace in any way. The deeper rim is stiffer and therefore spokes last longer too. These can be used everyday and given you get a wheelset that is useable everyday why would you comprimise on the aero gain?

power required to sustain a given speed is directly proportional to the CdA of the rider+ bike. Given you see a 4 to 5% or so reduction in CdA when going from open pro rims to a good aero wheelset (450W with 20W saved with the aero wheels) going by wheel test data from Zipp e.t.c. the actual numbers maybe a bit different but it is the order of magnitude that is important here to get a feeling for the gain. That is CdA is 4% or so lower with the deep rims than with the open Pro's. A mid depth wide alloy rim probably save 2% or so over the open pro's maybe it does better than that.

The difference between the 38mm deep and 50mm deep wheelsets will be small aerodynamically but it is real. The weight difference is not relevent and performance in side winds is similar so I struggle with the mid depth carbon clinchers. They exist because people think they are an all rounder without being any more of an allrounder than there deeper cousins.

If you go for a shallower wheel then go with alloy rims as the rims are cheaper at least. a Kinlin XR31T is not not much heavier, has similar aero credientials and you save money. With my logic if buying carbon go deep or go with mid depth alloy rims. The only point in a mid depth carbon rim is if they are tubular and silly light but even that wont translate into much of a gain.

nickcube
Posts: 142
Joined: Mon Feb 23, 2015 8:01 am
Location: Melbin, 'Straya

by nickcube

bm0p700f wrote:wrong a u shaped 50mm rim best again aero trumps weight every time. going shallower does not improve performace in any way. The deeper rim is stiffer and therefore spokes last longer too. These can be used everyday and given you get a wheelset that is useable everyday why would you comprimise on the aero gain?

power required to sustain a given speed is directly proportional to the CdA of the rider+ bike. Given you see a 4 to 5% or so reduction in CdA when going from open pro rims to a good aero wheelset (450W with 20W saved with the aero wheels) going by wheel test data from Zipp e.t.c. the actual numbers maybe a bit different but it is the order of magnitude that is important here to get a feeling for the gain. That is CdA is 4% or so lower with the deep rims than with the open Pro's. A mid depth wide alloy rim probably save 2% or so over the open pro's maybe it does better than that.

The difference between the 38mm deep and 50mm deep wheelsets will be small aerodynamically but it is real. The weight difference is not relevent and performance in side winds is similar so I struggle with the mid depth carbon clinchers. They exist because people think they are an all rounder without being any more of an allrounder than there deeper cousins.

If you go for a shallower wheel then go with alloy rims as the rims are cheaper at least. a Kinlin XR31T is not not much heavier, has similar aero credientials and you save money. With my logic if buying carbon go deep or go with mid depth alloy rims. The only point in a mid depth carbon rim is if they are tubular and silly light but even that wont translate into much of a gain.


That's pretty much what I've been thinking, if I'm going to go carbon I might as well go deep(ish). The shop I work at said Reynolds have sales occasionally too on their wheels so if they're going cheap at cost price, I might hit those up. Otherwise the budget says RS81 C24's are the only real option still

istigatrice
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by istigatrice

Second what bm0p700f says. In particular, as a do it all wheel it's hard to beat the XR31T if you're sticking to alloy. For a period of time I was only able to have one set of wheels, and that set of wheels was a set of XC-279 rims (very similar to XR31T) laced to novatec hubs. For everyday use they're strong, light enough (mine were 1572g with regular novatec hubs, i.e. not SL, I think you'll be able to get 1500g flat with the XR31T) and offer some aero advantage over something like the C24. In Australia, BDOPcycling are able to get build kits with either the XC-279 or XR31T rims for under $500 shipped (just need to find a wheelbuilder or DIY).

I'd also like to add that while the RS-81 C24 and Pro-Lite A42s are both very nice wheels, I wouldn't have them as 'race day' wheels (I'm not saying you can't race them, but you might as well race the Aksiums and spend the money on faster tyres/tubes and race entries). Again if you just want something new, and something that'll make your bike 'feel faster'/'look cooler' then both are reasonable choices, but if you're after a gain in terms of speed/free watts then I would look elsewhere (or at other wheels). I'm basically saying don't expect either of the two choices to 'outclass' the aksiums. Ultimately, they are all just narrow(ish), aluminium rimmed wheels.

If it HAD to be one of the two then the C24 would take it because I doubt the A42s are very aero with anything wider than a 21mm tyre, and unless you're 54kg I doubt you'd be happy to run a 21mm tyre (I did vote for the aero option, but that's provided it's a 'proper' aero rim).
I write the weightweenies blog, hope you like it :)

Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)

by Weenie


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