Yes and use the SILCA tire pressure calculator on their website

Use calipers to measure your tyres pumped up. Your 25 or 28 might measure 27 and 29 etc
But as above use the Silca Calculator but for measured width not advertised width.
And you don’t have to run them tubeless..
I run a 25 front And 28 rear with Latex Tubes.

Thanks
And how do you find the puncture resistant compared to the standard gp5000 ?

I got my first ever puncture in a GP5000 I have been riding multiple wheels for several years now about a month ago and was glass or something that blew almost all the puncture protection out and was lucky to seal and limp home. I use the TT version on my race wheels and have had no punctures so this may help you.

Road Bike Tires Test Results | Bicycle Rolling Resistance

I ran the TTs this summer with no flats, but I am using them tubeless so all the little stuff like wire and thorns is taken care of with the sealant. If you are running tubes you might be better off using the Vitoria Corsa Speeds. They have a lower rolling resistance and a puncture belt/strip, so in theory they might be less flat prone.

I find running race tires with sealant is pretty reliable. The closest I came to getting a flat was when I ran through a broken bottle. I didn’t think anything happened and continued on my way to a local TT. When I got back I noticed sealant all over the rear of the bike and a good cut on my Corsa Speed, but pressure was still good enough to set a PR.

Barely. At least according to BRR. 0.00225 vs 0.00228 @100PSI/25mm.

That has to be close to the error bar on the measurement equipment.

Also the GP TT TR has the same Vectran puncture belt as the regular TR. Just 0.5mm less rubber tread and only two layers of casing in the sidewalls instead of 3.

I rode 3k miles on my gp5000s before i got my first flat last Saturday - and it was a pinch flat because i jumped the curb too aggressively. I run 25s at 78 psi btw.

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Next races on the schedule: none at the moment

I was wrong about the TT not having the puncture belt. My bad. The AeroCoach Crr data has a bigger gap with the values being 002216 vs 0.002042, or roughly 2 watts and Marc Graveline talked about some testing he did on the Cycling Time Trials podcast that put the Corsa Speed ahead of the 5000 TT doing on road testing.

There is probably enough tire-to-tire variability that it makes sense to look at multiple sources and rolled testing individual tires is probably a good idea if you are really anal retentive.

Are the Contis true to size or they balloon much on the rim?
I might be leaning towards Vittoria because they have a 23c version that might fit better on my HED Jet Black 60 (21mm width internally and 25mm ext width)

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What's your CdA?

Continental Grand Prix 5000 clincher in 23mm.

I measured the 23 CS at 23.4 on a HED Jet. This is an old tire, so there is probably some casing stretch.

The latest Marginal Gains podcast talks about tire selection on a similar wheel and the rule of 105. Josh said 23 on front and rear. I always ran a staggered 23/25, so I guess I have been doing it wrong.

I've run various sizes of the Conti 5000 TL and S TR on Jet + rims, and without fail they measure out at least 2, maybe 3 mm wider than the nominal size.

Thanks, I used to run a Continental Supersonic 20c on the front which measured 24.2 inflated. Unfortunately it develped a sidewall crack and died :(
I still have two old style 23c supersonics from back in 2016 which are in pretty good shape but they inflate to 26mm on the Hed Jet. Still damn fast tires and never had a flat on them.

I'll probably give the Corsa Speeds a go.

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What's your CdA?

So is there a difference between a non tubeless tyre and TR
So if I’m not running tubeless then is it a disadvantage to run the TR tyre

Is the gp 5000 tt even available in a non tubeless version ?

Thicker beads, less permeable casing, ... (often more expensive)

Likely you could make a very similar tyre slightly faster if you knew it'd be run with a tube. In practice the difference seems to be tiny, and also somewhat countered by the manufacturers more likely to make a thinner thread on a TR than non-TR, since the sealant would take care of some of the puncture protection...

No

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