So we’ve been doing a lot of testing recently and I thought this would be of interest, you hear a lot about how Vittoria tyres aren’t aero and Conti are - this was more true in the past as the Corsa Speed (not the Corsa Pro Speed, the older one) was pretty bad for aero but made up for it in Crr vs. the corresponding Conti at the time. The new Corsa Pro Speed has got a totally different construction and is actually pretty good, something we found out a while back when testing the early 24mm on our Titan 100mm wheel.
The data below is from top end time trial wheels, some are multispokes, some are deep sections, internal rim widths ~20-23mm ish, using Conti 5000 TT and Corsa Pro Speed both in 28mm listed size. Because the Conti blows up so wide, it ends up being a good 2-3mm wider than the Vittoria, which in turn makes it on average less aero, using a weighted yaw average from 0-15. The wheel with the flat line in the middle is the only one which is marginally more aero with the Conti, but those data points are well within the margin of error. On one of our 21mm internal wheels, a 28mm Corsa Pro Speed at 90psi is ~28.0-28.2mm, and a 25mm Conti 5000 TT is ~27.0mm, making that a much better comparison. Issue with that is you can’t use a 25mm 5000 TT on a 22mm internal!
I hesitate to reach into this, but humour me.
Never mind what the listed width of a tyre is, surely to have a reasonable comparison it’s the ‘actual’ width that should be as close as possible. And if that means a conti 25 v a 28 corsa that’s “fair”. Unsurprising the conti 30 (actual) has a larger CdA, dragging it down overall.
As for “can’t use”, again it should be the actual width that matters. So that conti 25 on the 22mm internal rim width would inflate to 27.5 (which is ‘safe’).
Have these points merit?
Worth a thread title amendment btw?
Yes, definitely the end use case is important. From a consumer perspective though you can’t know what things will inflate to, so you have to go by what it says on the tin effectively, and from a company perspective you’re limited by the tyre manufacturer recommendations (if we sold a 22mm internal wheel we can’t allow a 25mm tyre under ETRTO). I think my main point was it’s a bit of a minefield - and that the 25mm GP5000 TT is still an excellent choice as people seem to be moving away from it a little bit from what we can see.
So is your summary that in 28mm, on a 22m internal wheel, Corsa Pro Speed is more aero than a Conti 5000TT and rolling resistance tests show it also rolls faster ?
Any opinion on durability ?
We are knee deep in testing/comparison for IMCanada, specifically with these tires, so especially curious on that 2nd point since we can’t really test it
On average, that’s what we saw from this data set across wheels ~20-23mm internal, yes. It won’t be true for absolutely everything I’m sure but in real world use we’ve not seen a Conti 5000 TT beat a Corsa Speed yet, on our wheels at least!
Durability wise I’d lean towards the Conti. I road race on Conti TTs and time trial on Corsa Pro Speeds!
Yesterday was TT vs CorsaPro. Today is TT vs CorsaProSpeed.
On one hand I wish the TT wins because I don’t want to have to make a decision.
On the other, faster is always funner.
Overall speed is what matters so I don’t think there’s any need to get the Crr/CdA contribution if you’re testing systems. I wouldn’t bother testing the 5000 or the Corsa Pro personally, just the TT and Corsa Pro Speed.
yes and no. It’s for IM, and flat protection is part of the equation.
I usually don’t tell someone (in this case my buddy), use this or use that. I prefer to say “this is giving you X watts, chose based on the other stuff”. And since he has 5000s well, is X worth the extra cost. And it makes for more tests which are fun.
The 5000s will probably just end up on training wheels. I do believe stronly in race vs training wheels and tires
We are testing on good and bad roads, there is a component to that.
IF ProSpeed ends up being really fast, I might just ride the rest of the summer with them to see how often I flat
Thanks for starting the thread, it’s timely (for me).
My view is that is exactly what VE does and is exactly the right tool for relative comparisons. Since VE relies on ascribing both a RR and a Drag component, the RR values can be meaningfully compared. If the RR attribution between two different tires is the same, the behave the same - from a rolling resistance perspective. Admittedly, drag relies on the assumption that all other components that contribute to drag remain the same from
repeated A B tests.
This is super cool! I’m refusing to go below 28 mm anymore between my weight and road surfaces, so I really appreciate this. Now I just have to choose between a HED H3+ or Jet 6 for my Dimond. Thank you for your continued contributions here!
better to have more data than not if you can get it!
