Which (tubular) tyres are you running on your Bora One/Ultra?

[userfriendly]

The new Boras were certainly designed with slightly wider tires in mind, but I've never heard of Campy specifically recommending against using 23's. But, having mounted both, I prefer 25's over 23's on the new Boras and 23's over 25's on the pre-2015 Boras. I wish Veloflex still made a 24mm tubular because I think that is the ideal size for me and how/where I like to ride.

It was actually here on this board: viewtopic.php?p=1148690#p1148690 - but maybe I misunderstood:

The Bora 35 is a C15 rim and as such, following the general rule of ISO bead width x 1.45 -> 2, would be OK with a 23c tyre on it.

However, at the 2016 Technical meeting for Campagnolo branches last week, all the senior mechanics present agreed that a 23c, especially a comparatively narrow 23c, would be best avoided and that the 25c, for which the rim was designed in any case, would be the best choice.

Of course some 23c tyres are wider than others - Michelin might be OK, where Conti might not afford enough protection to the rim, for instance.

I have 2015 Bora One 50 tubs with Conti Competition 22mm front and 24mm rear tires.

The reason I split the tire width is because I was reading that it would be more aero - blah blah blah. In practice, I would NOT recommend it. It feels much harsher as there is much less air inside. Looking side on, you can easily see the height of the tire is much less (ie. less volume). If I had my time again, I would go even tire sizes and/or avoid 22mm tires as they are just too narrow and harsh.

I don't race so and I run low tire pressures too - YMMV.

Fair. That does make me lean towards the 25mm, or maybe 24mm if the clearance isn't there for 25. Was interested in this kind of setup mostly because that's what I'm currently running the clincher wheels at on the bike that will get the Bora's, and it's pretty tight looking in the rear with the 24mm Conti Force clincher. Maybe about 2mm distance to the seat stay bridge.

[userfriendly]

Got the wheels today 1,235 grams, 30 grams under the claimed weight. Now to dry-mount the cheapo testing tyres to check clearance on the frame ...

[userfriendly]

Clearance with the 25mm Vittoria tubular is the same as with the 24mm Conti clincher. 25mm tubulars are a go, then.

[helldiver]

Veloflex extreme (22mm, 350tpi) front, Veloflex carbon (23mm, 320tpi) rear on Bora One 50, very happy with that combination.

Interesting. May I ask what made you go with that setup? I.e. two different tyres front & rear, and narrower than rim width?

Sorry for the late answer - I wanted to have 22mm front for aero reasons (tyre should be 2-3mm narrower then rim width to optimize aero), in the rear, this is not so important (wheel is mostly shielded anyway), so 23mm or even 24-25mm tyre is better option. 23mm Veloflex Carbon measures 23,5mm when inflated to ~7bar, so it's almost as wide as 24,2mm rim.

[Calnago]

If aero is your main criteria then the bora clinchers would be a better option. The rim tire interface on the clinchers is "much" more aero. Of course, if handling is your main criteria, then tubulars for sure.
It's interesting that a set of 23mm or 22mm tubulars on the Pre-2015 Boras also have a very smooth rim/tire interface, much moreso than the 2015 Boras (tubular). But in reality, I have a tough time even talking about the rim tire interface with a straight face since I don't believe it matters a whole lot or even a little bit in the real world. But I suppose if they test it to the n'th degree they can prove that airflow is better if there is a completely smooth transition from the tire wall to the rim. So, if it matters to you...

[userfriendly]

Thanks again for the replies, guys No, I'm not mainly after aero benefits. Why did I buy deep section wheels then, you ask? I may have bought them mainly for their good looks. Hey, that's a perfectly valid reason! ... I'm shallow, but the deep rims make up for it?

Besides the looks I'm after ride quality (which I guess suggests I should go with 25mm tyres) and low weight (which suggests 23mm), and I wanted to try tubulars. Aero won't hurt, but I doubt I'm fast enough to use that as the main reason for the purchase ...

What I'm not quite sure about is where exactly to file the various tubulars in terms of puncture resistance. As mentioned I'm running Conti Force/Attack clinchers on this bike at the moment, with only one puncture during the ~1,400km I've put them through so far (it's the dry weather bike).

I'd kind of like the tubulars I get to be comparable in this regard: a reasonable amount of puncture protection, i.e. as much as they need to roughly match those clinchers but not more, if that makes sense. These tyres are only ever going to see dry tarmac.

[Calnago]

@userfriendly: my comment on aero preference was more directed at @helldiver's post where he is using a 22mm tire up front for "aero" benefits. Personally, I think a 22mm tubular is just too narrow for this rim.
And you are absolutely correct, nothing wrong with getting the wheels for their looks either. As for puncture resistance, I've had very good luck with the Veloflex. So I wouldn't worry about that too much. I actually really like the Continental Competition as a foul weather tire, and not because of its puncture resistance but because I feel it has really good traction in the wet. The only drawback to the Contis is that they're so damn difficult to mount, even with prestretching. At least compared to a Veloflex.

[userfriendly]

Cheers yeah, I'm not going to try Conti tubs then. Weak thumbs.

Not really worried about enough puncture resistance, rather about too much. I'm wondering how light I can go and still keep reasonable protection. As an example, I'm running Conti 4 Season on my tourer. Dependable, roll well, and not too heavy. The Force/Attack on the dry weather bike are a lot lighter, handle better, and obviously don't have the same amount of protection but they have 'enough' for doing 50-100 mile rides on dry days. So I'd kind of like to the get the tubular equivalent of these rather than the equivalent of the 4 Season. Does that make more sense?

[Calnago]

I think then 25mm Arrenbergs would be your best bet, or if you want tan walls, the Veloflex Roubaix, same tire, just one is a tan wall and the Arrenberg is all black.

[helldiver]

@userfriendly: my comment on aero preference was more directed at @helldiver's post where he is using a 22mm tire up front for "aero" benefits. Personally, I think a 22mm tubular is just too narrow for this rim.
And you are absolutely correct, nothing wrong with getting the wheels for their looks either. As for puncture resistance, I've had very good luck with the Veloflex. So I wouldn't worry about that too much. I actually really like the Continental Competition as a foul weather tire, and not because of its puncture resistance but because I feel it has really good traction in the wet. The only drawback to the Contis is that they're so damn difficult to mount, even with prestretching. At least compared to a Veloflex.

No, it's not too narrow, and it's common misconception that the tyre should match the rim perfectly in width for the best aero results. True is that the half-sphere cross-shape of the tubular tyre facing front (well it depends on where me make the virtual "cut", it's only half-sphere in the hub horizontal axis, getting more elongated moving up or down) has quite terrible aero properties, but you can't do much about it (teoretically, you could mold some tyre which will have better shape, but then handling would suffer...):

Focus on the upper picture (ignore the dimpled ball below), you can see how the flow separates quite early and the "flow-lines" actually get wider then they sphere diameter after the pass the first half of the sphere. Now you want this flow to re-attach to the rim, therefore the rim must be wider then the diameter of the sphere (tire) itself.
Here is one very good article debating the topic: http://aerogeeks.com/2014/04/03/aeromail-tire-size/
One quote from the article above (he is obviously talking only about aero performance):

Generally, the narrower the tire, the better the performance. As an example a 25 mm wide rim will perform best with approximately a 14 mm tire… that’s right I said 14 mm. The main reason rims are wider is because the wide rim trend is in response to wider tires. If you look at aerodynamic data from 1980, the overall wheel drag has not changed much. In the 1980s TT tires were 17 or 18 mm and rims were 18 – 21 mm wide. Today TT tires range from 21 – 25 mm wide, and rims are 23 – 26 mm wide.

[userfriendly]

No, it's not too narrow, and it's common misconception that the tyre should match the rim perfectly in width for the best aero results. True is that the half-sphere cross-shape of the tubular tyre facing front (well it depends on where me make the virtual "cut", it's only half-sphere in the hub horizontal axis, getting more elongated moving up or down) has quite terrible aero properties, but you can't do much about it (teoretically, you could mold some tyre which will have better shape, but then handling would suffer...)

Well, I suppose you could go for clincher tyres, since they're more aero than tubulars (there was a GCN video about that a wee while ago), but I'm not too keen on carbon clinchers. Yes, carbon clinchers may have come a long way, but I think I'd still prefer the inherent strength advantage of tubular rims over clincher rims if going carbon, both for weight and safety reasons.

Hmm. Maybe a 23c Veloflex Carbon in the front and an Arenberg in the rear?

Although I'm still a bit put off of 23c tyres due to what graeme_f_k mentioned in that other thread.

at the 2016 Technical meeting for Campagnolo branches last week, all the senior mechanics present agreed that a 23c, especially a comparatively narrow 23c, would be best avoided and that the 25c, for which the rim was designed in any case, would be the best choice.

[helldiver]

I very much doubt the aero benefits of the clincher tyres, I never saw it really proven anywhere (GCN video was everything but proper scientific test with controlled variables). 23/25 combo seems quite reasonable to me, you can see plenty of guys running new Boras with 22mm tyres even in Pro-peloton, 22mm Conti Competitions on Nairo's bike here:

The 23mm Carbons (which are actually >23,5mm when inflated) and 25mm Arenbergs (almost spot on 25mm according to many reviews) differ only very little in the tyre bed curvature, so it remains mystery to me what could cause Arenbergs to be "perfect fit" and Carbons "dangerous" .

[userfriendly]

It's probably hard to prove as the difference will be so minimal, unless you have a proper wind tunnel at your disposal. But purely going by how the clincher tyre meets the rim, as opposed to how a tubular does, it would make sense to me that there is a marginal, very marginal gain to be had. But yeah, like I said ... really nowhere near my main concern, and I've already got the tubular version, so ... meh.

Re 22mm, I'd be hesitant to try and mirror what pro cyclists are comfortable with, what with their bike handling skills being infinitely better than mine. That said, I do run a 22mm front tyre on that bike currently, and I quite like the sharp handling of that one.

[kgt]

In any case I would go for the best tire (the tubular that is) and forget about all this tire-rim combo aero BS.

[userfriendly]

In any case I would go for the best tire (the tubular that is) and forget about all this tire-rim combo aero BS.

Aye, clincher isn't even an option, seeing how my Bora are tubular rims. The thing I'm still undecided about is what tyre width to go for.

Looking at the Veloflex website it seems even the Sprinter/Extreme has, difference in pressures not withstanding, the same amount of puncture resistance as the Roubaix/Arenberg, so I guess I might as well go with the slightly narrower (and sharper handling / lighter) ones.