Campagnolo Bora AC3 Braking Treatment

[lw11]

Does anyone have any information on what the 'AC3' braking surface is on the Bora rims?

I was having a browse and noticed 'new' Bora Ultra wheelsets. I can't find anything on the Campy website or any other website for that matter.

http://www.bikebug.com/campagnolo-bora- ... 74215.html

[lw11]

Edit: delete this post. I've found another post(s) with more information. Sorry!

[maverick_1]

Here you go..

https://www.campagnolo.com/UK/en/CampyW ... next_level

[dj97223]

It is interesting that Campag rarely (if ever) provides aero data for its wheels but provides very specific braking data for these wheels. I rarely ride in the rain, so this improvement wouldn't do much for me (he said, resisting the temptation to crack open his wallet).

[Calnago]

Ok, so I received a set of the new Bora Ultra 50's yesterday. Haven't glued them up yet, but did dry mount a set of Veloflex Vlanderen 27mm tubulars just to see how they fit and check some clearances.

Basically, as far as I know only the brake track treatment has changed. What is different is that more of the resin has been removed than before leaving more raw carbon exposed. It feels a bit more "raw" for sure and I would expect it to give a bit more bite to the brake bads. Campagnolo claims that the it's marginally better in dry conditions but vastly improved in wet conditions. So I'll look forward to trying them out. The circular pattern in the rim I do not believe really does anything but rather it is just an artifact of the process used to remove more of the resin from brake track.

Here's some pics. There is one little spot on the rear wheel that I will ask about on Monday to make sure there is nothing to worry about and that if I do glue up some wheels and hear the slightest "tick" from that spot on braking, that they can expect them back. I really think it will be fine, but I will wait for their response before gluing up anything.

So, without further adieu....

A section of the new Bora 50 Ultra Tubular with a Veloflex Valnderen 27mm tubular dry mounted...


A closeup of the mark above the "A", which I will ask about on Monday... I really think it is just the area around a seam in the layup process that gets exposed a bit more from the process they use on the rim. I'll see what they say before gluing up any tires.



And here's a comparison with the brake track on my Bora Ultra 35s, Diamante brake track just prior to the most recent change to the AC3 track... you can see how the surface is quite a bit smoother...



And here's a shot from a bit different angle... which you may or may not be able to see the circular patter which a lot of people seem to be thinking it is what's making the difference in braking performance but I really don't think that's the case. Rather, I think the circular pattern is just a left over artifact from the process involved.



So, I wanted to check the clearance with the Vlanderen 27mm tubular on these rims under my C60 stays...
I dry mounted these tires on the older pre 2015 Boras just to see but due to the narrower rim profile and tighter radius these tires would "sit up" a bit and would not work in my C60. But since 2015 with the new 24.2mm wide rims, the tubulars sit just that little bit lower due to the larger rim bed radius and thus if you're on the borderline with clearance, this has been just the little bit extra I need to run 25's no problem at all in my C59, and even the 27mm Vlanderen could be run in my C60, although I'd want to test just much "chatter" I get from road debris being thrown between the caliper arms and the brake bridge in the rear and the fork crown at front. But I do think there would be just enough to be ok as is, especially if you're using the new Shimano 9100 brakes with the added clearance. I'm using Campy skeletons on my C60.

[RyanH]

Cal, could you provide some feedback on the ride differences between the Vlaanderen and Roubaix/Arenberg on the 2015+ Boras? I have a few sets of Vlaanderens sitting in the closet and have been waiting for the Roubaix to wear down so I can swap them over on the Bora 35s.

[3Pio]

Im wondering, wouldn't be easier to upgrade BrakePads like Reynolds done and improved wet braking performances?

http://aerogeeks.com/2014/04/29/reynold ... ds-review/

[Calnago]

Cal, could you provide some feedback on the ride differences between the Vlaanderen and Roubaix/Arenberg on the 2015+ Boras? I have a few sets of Vlaanderens sitting in the closet and have been waiting for the Roubaix to wear down so I can swap them over on the Bora 35s.

Haven't actually mounted them yet, and it's my first set, so you may experience them before I do... but I suspect it's just going to be more volume and hence cushier, and softer, and probably slower on good roads. I just wanted to try them out, but I suspect my main road tires will still be in the 24-25mm range. I do like the dotted tread on the Vlanderens however.

[Calnago]

Im wondering, wouldn't be easier to upgrade BrakePads like Reynolds done and improved wet braking performances?

http://aerogeeks.com/2014/04/29/reynold ... ds-review/

Apparently not... from the accounts I've heard wet braking performance is increased by quite a bit with the new Bora brake track. I've used the cryo blues on Reynolds wheels. More slots in the pads only goes so far. As for the new Boras, I will soon know exactly what 43% improvement (I think that's the number they claim) means in real life... sometimes nothing, sometimes something.

[nestornnk]

Hi Calnago
What campagnolo said about the mark on the braking surface??

[RyanH]

@Calnago, you'll probably get a chance to ride the combo before I do since I have a set of Ambrosio Nemesis inbound to do my wide tire duty. I found 27/28mm to be too wide on older rims like Reynolds 32s (~21mm wide). They provide a vague feeling. I'm thinking that there's an ideal ratio of rim width to tire width so it's possible the Vlaanderens will feel better on the Boras than they would on an older style rim.

[Calnago]

@RyanH: I have several sets of Nemesis/Record wheels. I don't really like running bigger than a 25mm tire on them. They are a quite narrow rim as well, no wider than your Reynolds at 21mm outside width at the brake track. And the Vlanderens are too big for a good fit on the old Boras. I think they'll be nice on the new Boras... just wanna try them out.

[Calnago]

Hi Calnago
What campagnolo said about the mark on the braking surface??

Nothing yet, it probably looks worse than it is all blown up like that. I just want to be sure. It's definitely at a seam where one layup intersects another. And feels pretty smooth. But I don't want to be hearing any ticks every revolution as if there was a nick in an alloy rim.

[Imaking20]

Cal, thanks for the mock up photos in the C60!

Mind sharing where you snagged the 50s with the updated brake track?

[RyanH]

The seller had to cancel my nemesis wheelset order so I glued up the Vlaanderens last night to the Bora 50s. On my Litespeed T3, it looked good to go but when I started riding I realized the brake arms were touching the tire when braking.

Open brakes:


Closed:


However, on my Litespeed Classic with Campy non-label brakes, there's loads of clearance:



I didn't snap a picture but on the Evo with eeBrakes, there was ample clearance at the brake.

While this is off topic, my initial riding impression of the Vlaanderens is that they do not gain any suppleness over the Roubaix, which probably means they are less supple than the Roubaix given I'm running them at 60/70 vs 70/80. Riding over bigger "crap" they seem to do with aplomb and I can get away with faster speeds cornering over broken surfaces. So, based on my brief ride I'd say get them if you have a use case for the extra width (e.g. dirt riding or cobbles) but for general road riding my recommendation would be the Roubaix.