Yup - not a big deal for most TT/Tri races, but a huge weight penalty for a hill climb. I hope everyone I race against goes full disc brakes and tubeless :-)

Edit to add that the weight penalty is mainly from the TL tires. Regular TLR tires such as Corsa Speeds don't have the built in tube, so no weight penalty. I'm really curious to see how much extra flat protection the TL tires give.

Some back-of-the-napkin calculations lead me to 234gms, Not 380. I assumed you were using 25mm TT tires, 2 oz of sealant per wheel at 57gms, 75gms for a latex tube and 25gms for a valve.

GP5000TL: 2*(300+57+25)=764gms.
GPTT: 2*(190+75)=530gms.

If you're using 23mm TTs, then add 20 gms.

For the sealant, I assumed 4 oz total converted to grams at 114gms. For the valves, I used a little more than double the 12gms that I9 39mm valves are advertised at.

If you run a full one pound difference through a wattage calculator you'll find that that makes a 1 watt diffetence up an 8% grade. Your difference was less than that and you are not running your tri up an 8% grade. I suspect if you took it out on the road and tested, that you couldn't even find a difference. After an argument with a guy one time I went out and tested a 10 lb difference on my rolling 10K course that I use and I finished within two seconds of each other. I never quite understand why people obsess over weight on a bike. The only thing I can think of is if the industry pushes it and so they follow along.

was using 23mm TT tires, but as you mentioned that is only a 10g difference per tire compared to the 25mm TT you included in the calculation.

The tubeless valves I'm using only weight 9gr, so dif should even be smaller.

we used the bike shop park tool bike scale before and after the change (everything else was the same on the bike), and there's were the 380gr dif was noticed.

Maybe the sealant weight more than that? Next time I put sealant I'm going to weight it first ..........LOL

234gr would be lot better than the 380gr we noticed :)

agree, I think even on very hilly IM courses there should not be a considerable penalty by that difference. Maybe if it was an only uphill TT yes.

I suspect people obsess over weight because it's easy to measure.

Weight plays a major role if you have to accelerate often - e.g. in MTB. It is even more pronounced if we are talking about weight at the rim. In MTB 380g at the rim is a night and day difference.

I recently swapped my wheels in MTB to 400g lighter and on my standard trails I improved all strava segment times within 1 month. By a fair margin too.

In TT you optimally accelerate once so probably not a major concern.

What you are talking about is a micro-acceleration and that has been shown (Tom a. from this site and others) to be a non-factor in performance. Wheel weight, even at the rim does not matter more than weight anyywhere else on your bike. The perception of rapid wind-up being easier contributes to what people "feel" is a performance gain, but it is a placebo. Smarter guys than me can explain the math but it has to do with how small a portion of the total package (bike and rider) changes. A one pound chainge in wheel weight is a .005 change in overall weight of a 180 pound bike and rider.
Plus, the whole weight at the rim argument completely ignores the idea that "an object in motion will stay in motion until acted on by another great force." While the heavier wheel/rim may take a very small amouunt more to accelerate, it also retains that kinetic energy and will hold speed better than a lighter rim.
It is a pretty easy and revelatory test when you have a power meter. Unless you measured the power required between your two Pr's, you really have no idea why you were faster on one than the other.

This is just a general comment and observation (from a long-time bike industry guy) - There has been a very clear and consistent increase in bike weights over the past 5+ years. It can come from things like tubeless wheels/tires (and sealant), disc brakes, integrated storage, and suspension systems. You can still get bike weights down fairly low - but you spend a lot more. Just as an example, my ~$2,500 Habanero rim brake road bike with Shimano 105 and alloy wheels weighs about 19 pounds - and the press bikes that I test usually cost 3x that in order to weigh less (and they're pretty much all disc brake / integrated / etc).

There's definitely a growing divide in the market. You can find some rim brakes here and there, and there are still some light weight climbing frames. But there's also a lot more high tech bikes that add weight in exchange for other things. Best example I can think of is the new Trek Domane - a 1,230 gram frame... BUT the suspension system is super smooth and it's a pleasure to ride. Compare that with something like the BMC Roadmachine at <900 grams... it's a nice bike, but doesn't have suspension and it rides completely different.

Anyhow - it sounds like weight high on your priority list, so you'll definitely want to shop accordingly.

He could be talking about "macro" not micro acceleration. In MTB, cross, crit, etc. one might have to make dozens or even hundreds of massive accelerations. Go to the criterium jump calculator site and you can see that it adds up. And on some of those jumps losing just one half-wheel of distance can be the difference between winning and finishing 20 minutes back.

Per lanierb, on road races finishing a long climb just 5 seconds off a lead group can mean you never see them again.

Weight absolutely matters in some types of racing.

Agreed 100%.

I'm riding the new Domane this weekend at Gravel Worlds. I rode the 2019 SL at DAMn last weekend and it was great, but the new bike is on an entirely different level. And has a TON more tire clearance, has more of a Madone feel, and is a bit more aero than the old bike. Absolutely can't wait! My data shows this bike to be very fast and fully setup with cages and everything mine weighs about 19# with Di2 Ultegra 2x. Can't wait!

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24 Hour World TT Champs-American record holder
Fat Bike Worlds - Race Director
Insta: chris.s.apex

the trouble is, everything matters when racing - weight matters, aerodynamics matter, handling matters, braking matters, rolling resistance matters... and not having to stop to fix a puncture matters.
IF tubeless can prevent that last one, then it might worth a bit of extra weight

Absolutely, I'm a huge tubeless fanboi, and the trade-off is worth it for me. Just pointing out that the cost is real in some situations. This tri-oriented forum tends to forget that for some races are decided in key moments rather than just by average speed over a fixed distance.

Integration seems to create some big penalties. The izalco max is still light at 890g for a M frame despite being a disc frame, but the integrated stem is 230g. Compare that to a Canyon CP20 aerocockpit which is 270g for the stem AND bar. The non-aero Bonti XXX bar/stem is 230g.

i assume you wouldn't intend to run sealant in your latex tubes.

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Dan Empfield
aka Slowman

haven't done that before, as have received info that is not as effective for punctures to use sealant in latex tubes comparing to how sealant works on a tubeless tire. Do you think it's better to use sealant in latex tubes as well?

For reference, I use latex tubes without sealant for training and racing and have around 1 flat/2years.

I have used sealant in latex with moderate success. 2 days ago I got a tiny slow leak puncture, went home, put in 1/2 oz sealant, and now that tube loses air more slowly than the good one on the rear without sealant.

But I have also had small latex punctures not seal...and tubeless punctures not seal....so....

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24 Hour World TT Champs-American record holder
Fat Bike Worlds - Race Director
Insta: chris.s.apex

i have heard the same thing you have, that sealant is better in tubeless than in latex tubes (less pressure lost prior to sealing). however, in triathlon, the name of the game is to not have to change a flat. therefore, even 20 or 25 years ago we were putting sealant in our tires, giving up 20 or 30 seconds or however much, to get the flat insurance.

i ask because if you were one of those guys who put sealant in your tubes then you'd want to compare weights with sealant in both rigs.

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Dan Empfield
aka Slowman

yeah, this is the big question that i've never really seen a proper answer to - how reliably do tubeless road tires seal?
to me the self healing aspect is the only benefit to tubeless and its one i haven't seen any evidece of quantified effectiveness for. of course in an ideal world with tubeless you never even know you punctured so evidence is going to be lacking.
there are however some clear downsides to tubeless which are to date still holding me back - clear and quantifiable downsides vs theoretical upside

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