https://soundcloud.com/...-a-cycling-coach-152

---

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/

I’ll believe it when I see it. Zipp’s 454 and 858 have pretty wild shapes but they made that work with rim brakes. Knight’s old rim shape already traded speed for stability... again, in rim brake format. Unless they add turbulators to the surface of the rim, I’m not buying their argument.

except they're talking about not trading speed for stability, but getting both by using a wider rim that will blend with a wider tyre, which can then be run at lower pressures. Better rolling resistance, better cornering, better compliance on rougher roads, and aerodynamics to boot.

That's what they're saying, anyway, but it is true that the disc removes a significant constraint on rim shape.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

There's nothing particularly earth shaking about ENVE's claims. If you have rim brakes, you have to place the brake track at a certain angle and spacing. If you don't have rim brakes, you can use whatever spacing and angle you want. Rim brakes impose a constraint that disc brakes don't require.

I've been riding a set of ENVE 3.4 Disc wheels for several months. The wheels are extremely wide for road wheels and the rims blend with the tire widths to make the combination more aero. In this application, that means the rim width transitions smoothly to a width that is greater than the width of the tire.

You repeat a lot of their marketing points...yet we never see the data that "proves" these points...I find that interesting :-/

---

http://bikeblather.blogspot.com/

I listened to that part of that "informercial", and their false premise is that rim braking is limited to a 28mm tire size. That's demonstrably not the case.

---

http://bikeblather.blogspot.com/

It's out there, Tom A. There's a relatively old white paper done by an engineer at Mavic that makes all the points. (I don't have the link, but it should be an easy Google search.) Two interesting things about the white paper that lend it credibility: (1) It was done at Mavic before they bought ENVE. ENVE isn't named in the paper, but they were a competitor at the time. And more to the point, (2) It was done at a point in time when Mavic offered no wheels that fit the preferred aerodynamic shape. All Mavic's wheels at the time had rims narrower than the recommended tire and rims with flat sections for the braking surface.

Except that's not what they said.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

Point of correction: Mavic did not buy ENVE. Both are owned by Amer Sports, a publicly traded Finnish company, and operate as separate brands (just like Atomic and Salomon, two others under Amer umbrella).

Point taken.

I remember the white paper well because I had been a Mavic rider for over 10 years. I was researching aero wheels and it was Mavic's white paper that convinced me to switch to ENVE for the road and HED for triathlon.

That was a funny point considering i am running 30mm tires in my DA rim brakes right now, rim calipers are not the problem. I also liked how they talked about their new aero bar shape as something new.....um Zipp, Specialized, Trek all flair their bar ends out, Enve just copied their design after nobody liked their first design.

Is this what you're talking about?
http://engineerstalk.mavic.com/...the-right-rim-width/

If so, I don't think it's saying what you think it's saying...and, if not, then you're going to have to point me to it, 'cause that's the best my Google-Fu came up with...

---

http://bikeblather.blogspot.com/

My 3t prima 199's from the early 2000's were flared too. It's not new, it's just new for them.

But on rim shape, what they were talking about was making a rim that blended smoothly into a wide tire, which requires a very wide brake track.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

At ~1:02:30 - "In a world of rim brakes, it's just...it's not possible because you have...you're limited by basically, 28mm is the maximum opening you get with a, like a Dura Ace caliper, for example."

OK...they didn't say "tire", they said "opening". No matter, 28mm is NOT necessarily a "hard stop" for what can fit in a bike with rim braking.

---

http://bikeblather.blogspot.com/

The "better rolling resistance" goes away when you adjust tire pressure for casing tension (which you should, otherwise you actually get worse compliance). Flo's first go with their casing tension study showed as much (and basic physics predicts that's the outcome). You only get "better" compliance if you drop air pressure below a casing tension equivalent air pressure. Wider tires let you do this because you have more volume and therefore more margin before you get a rim strike. Wider tires do not automatically give you more compliance. Try pumping up a 2.3" mountain bike tire to 60 psi (which would be "low" for a road bike tire) and see how it rides. Actually.... don't. The tire might blow off the rim. Because of casing tension.

It may not be a hard stop, but you still have to design around the most common calipers, plus factor in pad /rim clearance at a few mm per side. That's what they're talking about.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

What you're saying is that you have more range to play with in a wider tyre, dialing in more or less compliance as necessary.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

Correct. You can dial in the same compliance with a narrow tire as well, you just risk a pinch flat or destroying the rim on a big impact. At the end of the day, the tire just acts as a spring.

Yes, for bad roads and for training where your speed is of little consequence, wider is (generally) better. You might as well take advantage of the comfort and better traction.

But for racing, it is another story altogether. Because correctly inflated wider tires, all other things being equal, are NOT faster. Once you factor in aero drag, for racing, you actually want to run the narrowest tires possible that are appropriate for your rims (and the race conditions). And, if you are choosing race wheels, again you want to get the narrowest ones that are suitable for the race conditions (all other things being equal, of course).

---

Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

The way I understood it is that you want the tyres that best match your rim, not "the narrowest possible". A wider rim will push that optimal tyre width to be a bit wider, and more stable.

Reading between the lines of what the Enve guys were saying, it doesn't necessarily translate to lower drag in the tunnel at a given rim depth, but can make a deeper rim more useable in a wider range of conditions.

BTW, I got no dog i this fight, I'm riding Specialized trispokes and have no plans to change anytime soon.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

Let's not forget that Enve also recently said that their 8.9 was faster than a disc in the rear.

So? What does that statement have to do with this statement?

Let's just evaluate this particular line of reasoning instead, shall we?

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

I hear you about those tri-spokes, those are classics.

The problem is that, when racing, one typically wants low aero drag and low rolling resistance. "Stability" takes a far back seat to those two.

Wider and narrower tires, when properly inflated, are almost a wash rolling resistance-wise, but narrower tires still have the edge. However, narrower wheels and tires are nearly ALWAYS faster aerodynamically (all other things being equal, of course). Not sure if enve says this or not, but a little thing called evidence (the effect of frontal area on aero drag, etc) says it is so, at least to the best of my knowledge ...

---

Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

Except the claim is that not everything else remains equal.

---

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly