robncircus

Bored at work and this has been on my mind since a thread I read on WW. In that thread a member was asking about 38mm vs 50mm wheels and I was surprised to see so many people recommend 38mm wheels. Of course, it is WW and part of the response was due to the weight but the other logic was that in most race settings a rider is in a paceline or pack thereby negating most aero properties anyway.

Here is the thread for those that care: https://weightweenies.starbike.com/fo...829&hilit=38mm

So, with the exception ofepic breakaways, how important is the extra 1, 2, or 3cm? Is it more of a moot point due to drafting negating the reality of aero effectiveness?

Another reason I ask is because I'm not 100% happy with my current carbon wheels and was thinking of moving from the 50mm size to the 38mm size. I like the feel of the carbon wheels but would like something a little more tolerable for daily abuse.

Flame suit on

Rob

mattm

My Open Pros w/ 32 spokes each have done me well so far.

I don't think I would have any more points, or better placings, with aero wheels/rims. Well maybe in some close sprints, but I don't care enough to find out at this point. I'm pretty sure I can win on non-aero wheels, at least in our local 4's peloton.

If you're not happy with overall results, or whatever, a change in wheels (or any equipment) isn't going to solve it. What's wrong with what you have now?

Go do some intervals!

robncircus

Oh don't worry I am in no way implying my wheels cause me to be slow. I blame that on work/school/Navy/life/lack of training. I used to do just as well on my box section wheels as I do now.

I'm concerned with the build quality of my current wheels (I have some communication into the company) which is why I am looking for some new ones. Also, the current wheels have alow brake track and to swap wheels I need to readjust the pads each time. Royal PITA.

Hida Yanra

in a pack setting?.... I'll set sprinting aside, I'm not qualified to talk about it anyway ;-)
For conservation of energy expense- they are of negligible difference most of the time. If you want to work less, get better at drafting (watch cdr's videos or pro race videos for a reference as to how close you could/should be)
For aero properties in a TT or solo - yes, there is a difference, and IMO a noticeable one at that. The figures I've heard on slowtwitch and other places is that aero benefits don't really start accumulating until +/-40mm deep. You are currently at one of the 'sweet spots' aero-vs-weight, but below 40mm I've not noticed much difference in how the rims feel beyond how a light alloy rim would feel.

If you aren't going to be solo or TTing a lot, I'd ride whatever you want/like/think.makes.your.bike.look.hot
The fastest guys on our squad ride 32spoke Kings on OpenPros for mass-start races, and so far this year in regional stage races have placed 1st & 3rd in cat3... (This includes winning out of break-aways in the RRs)

ride what makes you happy

ridethecliche

Aero doesn't become less important in a pack.

If the pack is going fast, you'll have to expend less energy to be at that speed. Aero helps.

veloboy971

Zipp 1080's FTW!!! Seriously, a local pro (and coach of our college team) and I were talking about this and he was like when you run 1080's you don't even have to pedal. Aero makes a difference wherever you are, but if you're getting dropped off the back, it's not going to keep you in the race. They won't help you win if you're currently pack fodder, but if you're right there 5 seconds off the win in a TT, they will definitely give you an advantage.

waterrockets 

Even if it doesn't make much difference in a pack, nobody ever won a race without attacking solo, even if for only 50 meters. At that point, aero matters.

I'm with mattm in that it's not worth it to me to buy aero wheels for the sake of race finishes, but I don't discount the impact of aero wheels in a race finale. Many of my own wins have been in kilo attacks, and at 700W at 35mph for a minute, having a 20W bonus from a set of wheels is nothing to sneeze at. For now, I just rely on my position and hope for the best...

Look at Cavendish. He hides in the pack all day long, but he's adapted the most aerodynamic system for himself in that last 200m. Wheels are part of it.

This is how racing in a pack ends:

Grumpy McTrumpy

I've never been in a race or ride where I felt no wind at any time.

Hida Yanra

I agree that aero gear is always helpful, and yes, in a pack setting as well.
However, the OP asked specifically in the context of 38mm vs 50mm deep wheels. I still think that considering his question, there's no difference between those two options.

I'll freely admit that aero gear is important - I'm both a nerd and an ex-tri guy... so yes, I'm sold on that much.
Aero = VERY IMPORTANT BUSINESS
... for what the OP is about?

ridethecliche

2.4cm in rim reduction is nothing?

umd

Some people have engine to spare compared to the field and get away with aero bricks. I don't, I'll take all the help I can get. Even if you spend most of the race in the pack, as WR said, the sprint is going to be in the wind, and if you are in a break, or bridging, or trying to pull back a break, you may spend a good amount of time in the wind. In both of the races I won I spent a bunch of time on the front near the end. At Callville last year, the final attack to the line was a minute around 30mph IIRC. If I didn't have my aero wheels, maybe I still would have won, or maybe I would have been that much more tired from the rest of the race, and gone that much slower at the end that I would have been caught. They certainly help. Not a huge amount, but again I'll take all the help I can get.

umd

Sure there is a difference. Less than between 50mm and box sections, but a difference still. Would you also say there is no difference between 50 and 58? 58 and 66? 66 and 80? 80 and 88? Small differences at each step, but differences. If you look at then 38 to 88, you would probably think that is a huge difference, so somewhere along the way those differences had to be more than "nothing".

Hida Yanra

okay, okay,.... point taken, I concede

Clarification:
IMO, in the OP's situation, the difference isn't enough to change wheels over.

Grumpy McTrumpy

I have to use every ounce of power that I have, so any benefits, however small, are welcome.

robncircus

Glad to see I'm not the only one that isn't a little "distracted' at work today.

No worries. This is how I work anyway.

Good point.

I'm getting new/different wheels regardless. I have questions about the build quality of my carbon hoops and honestly don't know if I feel safe riding them.


Rob

mattm

Work? What's that? =]

What wheels are you on now, btw?

Hida Yanra

I was wondering how the longer-term outcome of those group-buy wheels was... sounds like "not so good"
the seller stopped selling them because of quality concerns, it sounds like there's something to that.

As a possibility (because I do love deep section wheels), consider a local builder look at them and rebuild them for you with your spec of hubs/spokes? You already own the rims and unless the rims are bad, it might be cheaper?
just a thought -

robncircus

Well I'm trying to be as positive as possible about the whole thing before I mention names but a quick look in the group buys section will reveal the "maker".

They were great when I first got them. However, they were both out of true within the first couple hundred miles. I had them trued and asked the LBS to check tensioning. They found a few loose spokes but nothing of conern. Recetly, a bulge developed on both sides of the valve opening on the rear wheel. I can actually squeeze the carbon with my thumb and forefinger and feel it moving (like the pop button on the top of a jam jar). I had a couple mechs check it out this weekend (a friend of my teammate is a neutral support mech for Sram so it wasn't just some Joe Schmoe) and both thought the bulge was abnormal but said it didn't appear to be structural. However, I've never seen nor heard of that happening on other carbon hoops.

All this combined with my rear blow-out on Sunday after some funky noises on the back and I've decided to give them a rest until I hear back. Worst case scenario they will go on CList for dirt cheap. I have the finances for some better wheels or custom wheels so I will see what happens and maybe get some new hoops. I do really like the "feel" of the carbon though.

carpediemracing 

Sorry to hear about the wheels. I hope your new frame is working out well.

As far as aero wheels in a field situation, I'm pretty sure I've made my position clear - they really help. Not in the slow stuff, not when you're waiting for things to happen, but when things go fast.

In a recent helmet cam clip I move up aggressively with a few hundred meters to go in the race. I'm going just under 36 mph (I didn't want to bother with details so I labeled it 35 mph, instead of 35.8 mph), with some crosswind (it wasn't a direct headwind, but it wasn't a direct tailwind either, although I labeled it a tailwind for simplicity's sake). I made the effort without going into my reserves, without killing myself - I felt good enough to uncork an extra long sprint which was good enough to win the race.

I won't credit the 60mm "hydrotoidal-mumbo-jumbo" wheels for everything (I had to pedal the darn things), but I think they really helped me out. Facing approximately 40 mph wind speed, I needed every bit of help I could use.

Although that's an extreme example, there are plenty where I bridged a gap, moved up, etc, all under pressure, all at relatively high speeds (35 mph or higher). Aero wheels help in those instances. So does being on the drops, having a relatively low position, etc etc etc.

I regret not buying a 90mm rear wheel, but I did buy a 60/90 set for training (and for flatter, less "acceleration" crits). A 90 mm front wheel may be a handful in many of my races since I tend to focus on Bethel (windy) and Nutmeg (sometimes very gusty). I wouldn't use a 90 front in most situations but probably in some. A 90 rear I'd use every race.

Of course wheels don't make the rider. I won't ever become a time trialer (it's painful to see in the Criterium de Bethel clip, which I'm uploading now). Combine any wheels with a 250w FTP and you have... a slow guy on really nice wheels. But for shorter efforts, 30 seconds, 60 seconds, I can hold my own, and there the wheels really shine.

cdr

waterrockets 

I just wish the rims weren't 10x as expensive. *@#$@#$!!!

My frugal side just can't deal with it.

mattm

+1

Even though I technically have the dough for nice hoops, it seems like they're always the first to go in a crash.

Dude wrecked his 808's in a training crit a few weeks ago - good thing he's loaded! It was a stupid crash, but really expensive.

Also, I would feel kinda silly with super-aero gear in a 4's race. (But apparently I'm the one of the few around here that feels that way..)

Goal this season: upgrade on Open Pros, and maybe even get a W. 64 spokes mofo!!

umd

Can we all agree to stop calling wheels "hoops" please?

Hida Yanra

I'm sure that you can agree to that...
getting everyone to agree?... man, this is the internet, complete agreement is unlikely, just saying

waterrockets 

We were talking about rims, not wheels. "Hoops" is fine.

waterrockets 

We were talking about rims, not wheels. "Hoops" is fine.