Vittoria Corsa Pro Speed rolling resistance data

Wheels, Tires, Tubes, Tubeless, Tubs, Spokes, Hookless, Hubs, and more!

Moderator: robbosmans

Forum rules
The spirit of this board is to compile and organize wheels and tires related discussions.

If a new wheel tech is released, (say for example, TPU tubes, a brand new tire, or a new rim standard), feel free to start the discussion in the popular "Road". Your topic will eventually be moved here!
xav
Posts: 269
Joined: Tue Dec 05, 2006 9:59 pm
Location: UK

by xav

We have updated our rolling resistance chart here:

https://www.aero-coach.co.uk/time-trial ... tance-data

An improvement on the previous Corsa Speed, around 4-4.5% which is similar to what Vittoria quote (5%). Sizing is a bit odd - the 23mm Corsa Speed and 24mm Corsa Pro Speed on our 19.6mm internal test wheel are basically identical in width, but the 26mm Corsa Pro Speed is only another ~0.5mm wider rather than 2mm wider.

Xavier

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



TobinHatesYou
Posts: 13009
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

The older Corsa Speeds had a fairly blunt shape once mounted and no siping pattern on the tread which negatively affected its aero performance vs GP5Ks. Do you think the Corsa Pro Speeds will give up similar aerodynamic drag losses?

Maybe the move is GP5K TT front and Corsa Pro Speed rear…

xav
Posts: 269
Joined: Tue Dec 05, 2006 9:59 pm
Location: UK

by xav

TobinHatesYou wrote:
Thu Feb 22, 2024 6:06 pm
The older Corsa Speeds had a fairly blunt shape once mounted and no siping pattern on the tread which negatively affected its aero performance vs GP5Ks. Do you think the Corsa Pro Speeds will give up similar aerodynamic drag losses?

Maybe the move is GP5K TT front and Corsa Pro Speed rear…
We've actually done aero testing on the new Corsa Pro Speed on our top end wheel (the 100mm Titan deep section) and it's faster aero wise than the old Corsa Speed as well as having lower Crr so good news really! Personally I will be using a 24mm Corsa Pro Speed on that wheel for TTs rather than a 23mm Corsa Speed or 25mm GP5000 TT.

Nickldn
Posts: 2008
Joined: Mon Mar 25, 2019 12:35 am

by Nickldn

xav wrote:
Thu Feb 22, 2024 6:29 pm
Personally I will be using a 24mm Corsa Pro Speed on that wheel for TTs rather than a 23mm Corsa Speed or 25mm GP5000 TT.
I guess what you're saying Xav is that you think the 24mm width Corsa Pro will be faster than the 26mm, at least on your 26.7mm wide Titan front wheel.

I'm switching to a 34mm wide front wheel from this year and 28c tyres, will be interesting how that compares to 26mm wide Bora WTO with 25c. Lucky enough to be able to test on the same bike and even using the same back wheel.

bobones
Posts: 1334
Joined: Mon Aug 12, 2013 11:19 am

by bobones

xav wrote:
Thu Feb 22, 2024 6:29 pm
TobinHatesYou wrote:
Thu Feb 22, 2024 6:06 pm
The older Corsa Speeds had a fairly blunt shape once mounted and no siping pattern on the tread which negatively affected its aero performance vs GP5Ks. Do you think the Corsa Pro Speeds will give up similar aerodynamic drag losses?

Maybe the move is GP5K TT front and Corsa Pro Speed rear…
We've actually done aero testing on the new Corsa Pro Speed on our top end wheel (the 100mm Titan deep section) and it's faster aero wise than the old Corsa Speed as well as having lower Crr so good news really! Personally I will be using a 24mm Corsa Pro Speed on that wheel for TTs rather than a 23mm Corsa Speed or 25mm GP5000 TT.
Quick question if I may. In your testing (for UK outdoor TTs), are there significant speed differences between tyre widths when rim widths are matched to the tyres and pressures normalized for skin tension? I'm intrigued by Josh Poertner's comments that the 3T Discus 45|40 (45 deep, 29 int, 40 ext) with a 32 mm GP5K S TR tested favourably in the wind tunnel compared to standard configurations.

xav
Posts: 269
Joined: Tue Dec 05, 2006 9:59 pm
Location: UK

by xav

Nickldn wrote:
Thu Feb 22, 2024 6:41 pm
xav wrote:
Thu Feb 22, 2024 6:29 pm
Personally I will be using a 24mm Corsa Pro Speed on that wheel for TTs rather than a 23mm Corsa Speed or 25mm GP5000 TT.
I guess what you're saying Xav is that you think the 24mm width Corsa Pro will be faster than the 26mm, at least on your 26.7mm wide Titan front wheel.

I'm switching to a 34mm wide front wheel from this year and 28c tyres, will be interesting how that compares to 26mm wide Bora WTO with 25c. Lucky enough to be able to test on the same bike and even using the same back wheel.
I actually think in that scenario there won't be much in it between the two because the widths are so similar. We were in the tunnel yesterday and just got the chance to test the 24mm, we will at some point put the 26mm on the Titan to see but the 24mm is going to be a safer choice.

I would say though that looking at the external rim width of a wheel should not completely determine your tyre choice. The "105% rule" or whatever it is really doesn't hold true with modern wheel technology and especially variations in the location of maximum rim width (this is really critical to tyre choice). It's just too simplistic a metric to capture what's really happening lower down the wheel rim so we don't subscribe to it and instead either collect/publish the tyre data ourselves on our own products, or get people to pester other companies to find out what the actual aero data is they've collected.

xav
Posts: 269
Joined: Tue Dec 05, 2006 9:59 pm
Location: UK

by xav

bobones wrote:
Thu Feb 22, 2024 6:56 pm
Quick question if I may. In your testing (for UK outdoor TTs), are there significant speed differences between tyre widths when rim widths are matched to the tyres and pressures normalized for skin tension? I'm intrigued by Josh Poertner's comments that the 3T Discus 45|40 (45 deep, 29 int, 40 ext) with a 32 mm GP5K S TR tested favourably in the wind tunnel compared to standard configurations.
As above there's a lot more going on in terms of rim shape and maximum rim dimensions below the bead hooks/brake track area which influences the aero drag of a wheel/tyre system that really you have to look at everything as an isolated case. Well, maybe that's a bit extreme (you're not going to run a 23mm tyre on the wheel you mention, there will be a range of tyre widths that would be appropriate) but in answer to your question I don't believe you can match the rim width to the tyre. You can choose a value or metric to try to do so, but a 28mm external brake track width on a wheel which is 40mm deep is going to require a wildly different tyre shape than a 100mm wheel of the same brake track dimension, for optimal aerodynamics.

I'm sorry that's not a helpful answer at all as not everyone can test everything :? but the best thing to do is go to the companies making the wheels and ask - they should have data on this kind of thing so that can help inform your choices much better than a standard metric.

Nickldn
Posts: 2008
Joined: Mon Mar 25, 2019 12:35 am

by Nickldn

xav wrote:
Thu Feb 22, 2024 7:35 pm
Nickldn wrote:
Thu Feb 22, 2024 6:41 pm
xav wrote:
Thu Feb 22, 2024 6:29 pm
Personally I will be using a 24mm Corsa Pro Speed on that wheel for TTs rather than a 23mm Corsa Speed or 25mm GP5000 TT.
I guess what you're saying Xav is that you think the 24mm width Corsa Pro will be faster than the 26mm, at least on your 26.7mm wide Titan front wheel.

I'm switching to a 34mm wide front wheel from this year and 28c tyres, will be interesting how that compares to 26mm wide Bora WTO with 25c. Lucky enough to be able to test on the same bike and even using the same back wheel.
I actually think in that scenario there won't be much in it between the two because the widths are so similar. We were in the tunnel yesterday and just got the chance to test the 24mm, we will at some point put the 26mm on the Titan to see but the 24mm is going to be a safer choice.

I would say though that looking at the external rim width of a wheel should not completely determine your tyre choice. The "105% rule" or whatever it is really doesn't hold true with modern wheel technology and especially variations in the location of maximum rim width (this is really critical to tyre choice). It's just too simplistic a metric to capture what's really happening lower down the wheel rim so we don't subscribe to it and instead either collect/publish the tyre data ourselves on our own products, or get people to pester other companies to find out what the actual aero data is they've collected.
Thanks, I think we like(d) the 105% rule because it was simple to understand, if not to apply.

Now it sounds like we have to rely on manufacturers doing testing and actually telling the truth about it. Transparency is a big issue in the cycling industry and to a large extent outfits like yours, Tour and BRR are the only way to truly verify manufacturers' claims. Keep up the great work.

xav
Posts: 269
Joined: Tue Dec 05, 2006 9:59 pm
Location: UK

by xav

Nickldn wrote:
Thu Feb 22, 2024 9:32 pm
Thanks, I think we like(d) the 105% rule because it was simple to understand, if not to apply.

Now it sounds like we have to rely on manufacturers doing testing and actually telling the truth about it. Transparency is a big issue in the cycling industry and to a large extent outfits like yours, Tour and BRR are the only way to truly verify manufacturers' claims. Keep up the great work.
I know, me coming on here and saying "forget the 105% rule" but not giving an alternative apart from "go ask the manufacturer" is a bit rubbish, but honestly it really is the right answer! Certainly getting independent data for tyres and wheels when it's not the manufacturer doing the testing is almost impossible - from our perspective we have a huge volume of data on other brands and their wheel & tyre interactions but we don't publish it because it's not our job to help them sell their products. But hopefully over time the more the consumer demands data the more that brands will be obliged to provide it, which is only a good thing for everyone :D

Nickldn
Posts: 2008
Joined: Mon Mar 25, 2019 12:35 am

by Nickldn

xav wrote:
Thu Feb 22, 2024 11:46 pm
Nickldn wrote:
Thu Feb 22, 2024 9:32 pm
Thanks, I think we like(d) the 105% rule because it was simple to understand, if not to apply.

Now it sounds like we have to rely on manufacturers doing testing and actually telling the truth about it. Transparency is a big issue in the cycling industry and to a large extent outfits like yours, Tour and BRR are the only way to truly verify manufacturers' claims. Keep up the great work.
I know, me coming on here and saying "forget the 105% rule" but not giving an alternative apart from "go ask the manufacturer" is a bit rubbish, but honestly it really is the right answer! Certainly getting independent data for tyres and wheels when it's not the manufacturer doing the testing is almost impossible - from our perspective we have a huge volume of data on other brands and their wheel & tyre interactions but we don't publish it because it's not our job to help them sell their products. But hopefully over time the more the consumer demands data the more that brands will be obliged to provide it, which is only a good thing for everyone :D
Totally think you're one of the best placed WW contributors to make these recommendations Xav. I guess publishing all your aero data would be costly and its not surprised you have not done that.

It sounds like 105% rule is still valid though and provides a belt and braces approach to getting an aero front wheel setup. But it does not mean a setup not adhering to this rule is not aero. :shock:

I'll stick to my new 34mm wide CRW front with 28mm GP5000S TR. That's more like a 120% setup.

BigBoyND
Posts: 1546
Joined: Mon May 31, 2021 1:51 am
Location: Berlin, DE

by BigBoyND

Nickldn wrote:
Fri Feb 23, 2024 12:05 am
I'll stick to my new 34mm wide CRW front with 28mm GP5000S TR. That's more like a 120% setup.
I doubt a 28mm S TR measures 28mm on that wheel. It'll probably be ~110%

ichobi
Posts: 1898
Joined: Thu Jan 19, 2012 11:30 pm

by ichobi

Thanks Xavier for the updated test.

I have a question which may related to this thread and it has been boggled my mind for quite sometime. Do you have any insight as to why Specialized sponsored pro teams still use the S-Works turbo cotton tires? On road application that does not surprise me given they use it with latex tubes and it’s still one of the fastest road tires (in your test).

However what I don’t get is in the time trial application - they also use the turbo cotton. Which looks like they are leaving 6-10 watts (per pair) on the road. I am sure for really critical race specialized would not mind Remco using an unlabeled corsa speed tlr or conti tt?

Or tire crr does not matter much for some teams in the grand scheme of things? I know the crr is constant vs cda where you get exponential benefit as you go faster. But that can’t be it given how obsessed to minute details some of these riders are.

TobinHatesYou
Posts: 13009
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

ichobi wrote:
Fri Feb 23, 2024 2:50 am

Or tire crr does not matter much for some teams in the grand scheme of things? I know the crr is constant vs cda where you get exponential benefit as you go faster. But that can’t be it given how obsessed to minute details some of these riders are.

Frankly it matters a whole lot all the time, especially on climbs where the aero component is diminished. The Turbo Cotton was fast 7-8 years ago, but as you say, now they're just leaving roughly 10 watts on the table for a pair of tires at road race speeds.

There's a reason why the team leaders on VLaB are riding Corsa Pro Speeds in road races and the serious Conti sponsored teams are using GP5K TTs.

da123
Posts: 506
Joined: Mon Feb 07, 2011 10:42 am

by da123

TobinHatesYou wrote:
Fri Feb 23, 2024 5:21 am
ichobi wrote:
Fri Feb 23, 2024 2:50 am

Or tire crr does not matter much for some teams in the grand scheme of things? I know the crr is constant vs cda where you get exponential benefit as you go faster. But that can’t be it given how obsessed to minute details some of these riders are.

Frankly it matters a whole lot all the time, especially on climbs where the aero component is diminished. The Turbo Cotton was fast 7-8 years ago, but as you say, now they're just leaving roughly 10 watts on the table for a pair of tires at road race speeds.

There's a reason why the team leaders on VLaB are riding Corsa Pro Speeds in road races and the serious Conti sponsored teams are using GP5K TTs.
I agree with the point, but aren't Aerocoach's tests for a pair of wheels, so it's actually 5 watts? Would be interesting to know how easy the Corsa Speed Pro is to set up tubeless, given the 'mixed' comments on set up for the Corsa Pro on BRR.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com



xav
Posts: 269
Joined: Tue Dec 05, 2006 9:59 pm
Location: UK

by xav

ichobi wrote:
Fri Feb 23, 2024 2:50 am
Thanks Xavier for the updated test.

I have a question which may related to this thread and it has been boggled my mind for quite sometime. Do you have any insight as to why Specialized sponsored pro teams still use the S-Works turbo cotton tires? On road application that does not surprise me given they use it with latex tubes and it’s still one of the fastest road tires (in your test).

However what I don’t get is in the time trial application - they also use the turbo cotton. Which looks like they are leaving 6-10 watts (per pair) on the road. I am sure for really critical race specialized would not mind Remco using an unlabeled corsa speed tlr or conti tt?

Or tire crr does not matter much for some teams in the grand scheme of things? I know the crr is constant vs cda where you get exponential benefit as you go faster. But that can’t be it given how obsessed to minute details some of these riders are.
It's only 5w for a pair of wheels at 45kph, and that's with the advent of the new Corsa Pro Speed. Compared with the old Corsa Speed it's 4w/pair, and vs. the GP5000 TT it's 2w/pair so not that great a difference, and I think for the riders knowing they can corner just like on their road bike with the same tyres is of some benefit. Specialized also really don't let a lot of debranded stuff go through (yes yes, I know about the wheels :) ), and there are always compromises with Pro Tour setups, regardless of the team.

Certainly with things like helmets and skinsuits as a TT specialist sometimes you'll be fine one year with a good setup and the next year it just won't work for you, which can be quite frustrating for the riders that monitor it themselves.

Post Reply