Updated data for the 25c tubeless and clincher versions of the GP 5000: https://www.aero-coach.co.uk/gp-5000-tubeless-data

On modern wide rims like Flo and HED, do 25mm tires balloon out too much and lose watts to aerodynamics?

Caveat to that data which I just learned on Twitter...all of the Crr tests are done at 90 psi. According to my own calcs, based on the measured widths, if the 23C was run at 90 psi, then the 25Cs should be inflated to 80 psi to get the same "Berto 15% drop".

In other words, the Crr for the larger tires won't be as low "in the real world" as compared to the 23C as reported...and might tilt the overall demand results more in favor of the narrower tires...just sayin'...

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http://bikeblather.blogspot.com/

Sorta kinda, just looking at Tom A's one test.

The 24mm Turbo Cotton kinda sucked (at aero) on the HED Jet 6+ compared to its 22mm SW Turbo sibling on the same wheel. Of course that's just one wheel and one tire.

And there is other anecdotal stuff I've read here that suggests that ~23mm tires are the sweet spot for the front wheel on modern rims if you're going for every last bit of Cd. I think someone here (GreenPlease?) even pitches like 20mm tires on the HED Jet+, but, I, personally, would not attempt that.

I've always though the interesting thing about the below is that the classic narrow H3 with 19mm tires does not win at low yaw (excepting watts-to-spin and Crr, blah blah)

I believe you’re right about this coming from GreenPlease, but I think this is in reference to the latest 20c GP SS which with the new casing measures up more like a 23c tire.

I have been racing on this combo. The 20c SS measures exactly 25mm when mounted on a jet + rim, and looks perfect from an aero perspective.

How hard is it to get that tire on the HED Jet+ compared to a GP4000?

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What's your CdA?

easily done with hands, though a little tougher than a 25c 4000 (haven't mounted a 23c 4000 in awhile so can't speak to that).

So I was all excited about building up a road bike out of a cross frame for the 33c TL version of this tire. Was pretty sure I was going to go with the ENVE 4.5 AR disc wheelset, but just noticed they say this tire isn't compatible? Anybody know what's up with that?

No bead hook on the ENVE?

EDIT- Confirmed. Continental recommends against hookless rim designs for this tire.

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"They're made of latex, not nitroglycerin"

yes known... but what is special or unspecial about the 5000TL that it cant work like a Pro-One from Schwalbe can ?

Dunno, this is straight from the ENVE website...

Bummer

i think the best result can be
GP TT rear, 25mm
GP 5000 front, 23mm

Weird. I assumed all TLR rims were hookless these days.

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Any run that doesn't include pooping in someone's front yard is a win.

+1

Rear wheel I usually have 25mm around 115 psi (I'm 170 lb / 77kg)
Front wheel, either :
25mm 100 psi (road bike), as less weight on front wheel, and need for some grip
23mm 110 or 115 psi (P3 tri bike, 25mm don't fit, not enough clearance, and better aero with my rims size)

not a problem, 23mm 110/115 psi is around same resistance as 25mm 100 psi, as confirmed by BRR tests on GP4000s2, or other tests.

What internal rim width? Those psi are...excessvely high

Edit: typo

I'm thinking this may be the way too. I have been using gpTT 25 on both wheels, which are super fat Aeolus, 27mm wide at the brake track. It seems a 25mm gp5000 on the front may be the way to roll now.

Hello

Internal rim width : 15 (road aluminum) or 17mm (55mm carbon)

Found these rec. for road 25mm tires :
70 kg : 7,5 bars
80 kg : 8 bars

I'm 77kg, so go for 7,8 bars (113 psi) for rear wheel

Front wheel, remove 10 to 15% if 25mm. If go down to 23mm, in this case same pressure than rear 25mm wheel.

Globally remove 10% or 20% if wet (for grip).

This is coherent with discussions I had with most elite or pro using similar tires (with weigh adaptation, of course). And I'm used to ride on far than perfect road.

in front TT tire is not good because it is flat thread so not good for air flow. you need some thread, thats why gp4k or gp5k front

Disappointed they are not making a 24mm. I wonder if the 25mm will fit any better on my P2 than the 4000!?!?

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"The first virtue in a soldier is endurance of fatigue; courage is only the second virtue."
- Napoleon Bonaparte

yes, but the RR more than made up for it. With the gp5000 the gap of RR has seemed to have decreased significantly

I'm heavier than you, usually 80-82kg for races but above 85kg at the moment :(
For my road bike I use 23mm with 85-95psi at the front and 100-105psi at the back without any problems. I often ride on very bad roads and I'm using 15mm internal rims. In summer I switch to 25mm (23mm is needed for clearance from mudguards in winter) and with these I drop to about 75-85psi front and 85-90psi rear on the same rims.
On the tri bike I've got 19mm internal rims and I use 25mm with 70-80psi on the front and 80-90psi rear.

Bad roads make lower pressures desirable IMO, especially on the front when riding a tri bike on the extensions without your arms providing the same shock absorbing duties they do on the road bike. Last time I got a pinch puncture was hitting a raised edge on a drain about 6 years ago so I'm certainly not running too soft for reliability. I do like the front at the mid to upper end of those ranges if I'll be sprinting or climbing on the road bike, just to avoid an excessively squishy feel.

Thinking it may be time to upgrade the race wheels to these tires, I appreciate the lower rolling resistance but I'm also a fan of the greater puncture protection. Hopefully the hype will die down and they will come down in price soon.

Really, marketed sizes have almost become irrelevant as measured sizes are almost always different....although rarely smaller on a road tire so your point is taken.