The Specialized Roval 321 is sweet disc. having raced it once I loved it. Converting to disc brake bike so have to let mine go with only 30 km on it. but hopefully will be able to replace with disc brake version

https://forum.slowtwitch.com/...ing=drgwood#p6755365

cheers

Thanks for reaching out! I have not gotten the Roval 321 yet so I went in the wind tunnel with Enve 7.8 Disc, and the results was down right awesome. And the bike looks so good, and will look even better with the disc in my eyes.

Regading tires, you testet it with 24 and 26mm? and the Schwalbe Pro one 25mm, correct? What tire is ideal for the disc regarding aerodynamic performance/rolling resistance?

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From the past research we have done for rear wheels, the Turbo Cottons beat nylon constructed tires every time (rolling resistance delta by far outweighs the aero delta, especially in a rear wheel). Regarding 24mm vs. 26mm, those two are extremely close to each other - less than one Watt, indicating that the optimum is somewhere around that size depending on conditions. "Ideal" will always depends on the details of the course and speed, but it won’t sway it much. ~<0.5 Watt in either direction. A "slower" course with high yaw and rough surface (Ironman New Zealand) might be better with a 26mm where this year's IMWC would point toward 24mm.

If you pair with our CLX64 front (which is class leading in every category for weight/depth/aero) use the 24mm tire up front.

-SD

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Hi Dave,

I just picked up the Roval 321 and it looks great! The only issue I got now is that I cannot fit the Schwalbe Pro One on the disc. It was very tight to get on the Enve 7.8 SES, but on the 321 it feels impossible. At least I am not strong enough. Do you have any recommended tubeless tires?

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If you weren't able to get the schwalbe on definitely dont go with the corsa speed. That one was a real beast for me to get on. You might what to put the schwalbe on a clincher rim with a tube and stretch it out for a few days.

If you want to see my struggles I did do an unboxing and a tire install on the 321.

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Hey Allanhov,

The Pro One does fit, but admittedly it is stubborn. Make sure you arent using rim tape, the tire is fully in the drop center, starting from opposite the Valve, and that if your tire lever slips...restart completely...

Allan,

If you're not familiar with this tool I'd recommend adding it to your inventory: https://www.jensonusa.com/...ead-Jack-With-Handle

Have you seen these recent BRR test results? https://www.bicyclerollingresistance.com/...nd-prix-5000-tl-2018

Comparison of TLR top rollers: https://www.bicyclerollingresistance.com/...ria-corsa-speed-2016

The thought of that tool was running through my head when I was trying to mount that Corsa the first time on the 321. However, it was so far from going on and the pressure required so high, that I felt like I was going to damage the rim. Especially if I tried to pry it on. FWIW, I have never struggled mounting any tire prior to this setup and I've done a few in my day. ;)

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quote LAI]
That sux. Sounds like a crazy tight fit for a disc. On the plus side, compared some of the heavy duty fiberglass or metal reinforced plastic levers, I always figured the BeadJack would snap before it caused rim damage

S-Works Turbo 700c24c Road Tubeless Light
UPC 719676267074

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Thanks for the advice. I actually did not know that Specialized had high-end Tubeless Road tires (and not the dealer where I bought the disc wheel).

Btw, the look turned out quit awesome :D

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It was actually easy when I figured out the trick. I only used 10 minutes looking at the three bike mechanics at my LBS who wrestled it on ;)

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What size Schwalbes did you go with? Also, if you have to throw in a tube later or pull the tire to patch it, it should be much easier to get it off and back on. Stretching works wonders even just a couple of days. Took me just over 3 minutes without really rushing to get it mounted back up.

Oh, yeah, the bike looks good. Not a fan of your bar choice (aesthetics mainly), but the rest of the build was done well.

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have not tried a Schwalbe on the 321... but the TurboCotton 26c was not that bad in my opinion.

Yeah clinchers are easy. I have yet to find a clincher tire and rim combo that is even slightly trying....it's the tubeless tires that give issue. I'm sure if I mounted a TC to the 321 I would have the same pleasant experience you had. ;)

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25mm. I did put the tire on another wheel with tube and stretched it for roughly 24 hours but did not notice any difference. I am not sure I will be able to put in a tube if I have a flat during a race, which of course is not optimal.

I can agree that the Morf-Tech might not be the best looking aerobars (they grown on me from that perspective), but as in function they are absolutely kick-ass.

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I had not seen the BRR test. Thanks for sharing! I decided on tires in october 18 before going to the tunnel and neither the test or the GP5000 TL was possible to get. A bit more weight but with 2,9 watts less rolling resistance compared to the Schwalbe Pro One at 80 psi (my typical pressure) each tire that is nearly 2 minutes saved on a full 180km. Know anything how easy they are to fit compared to the Pro One?

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24 hours might be good for a tubular, but the construction of the TLR tires is much different than clinchers or tubulars. Specifically the bead. The lack of a true standard has led some to believe that they're making tubeless tires a touch small and rims a touch big to compensate....not sure if true, but experience says maybe. The Schwalbes, however, I found no different than a tight clincher to mount up on my Easton wheels. And a year later they go on and off quite easily. For reference, four days of stretching was enough to make mounting the Vittoria Corsa Speed significantly more tolerable. I'm going to go out on a limb and say the 321 is a bit big, but i bet that Spec's tubeless tires will mount up with little to no struggle. However, any other TLR tire might need a good week of stretching before it's doable for most.

I have the same tire 25mm mounted on my Eastons, which also have a 19mm internal like the 321. My 25 ballooned out to 28mm on that rim. And based off the photos it's looking like yours might be that large also. I think Dave said that it tested well on the 321? If so, that is damn impressive.

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I will try to stretch them longer next time then. I measured the width of the tires today and the Pro One on my Enve 7.8 SES front wheel was 26mm and as you 28mm on the 321. Anyone now the width on other 25mm tires? like the GP5000? It looks a bit wide.

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