Cervelo R5Ca / Di2 / AX Lightness 5.32kg

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964Cup
Posts: 195
Joined: Tue Dec 18, 2012 1:31 am

by 964Cup

Well, I'm doing 250k tomorrow on Schwalbe One 25c tubs; let's see if I flat.

by Weenie


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superdx
Posts: 524
Joined: Sun Jun 29, 2014 1:27 pm

by superdx

I would say that different tubs do slightly better at higher pressures, but I only have experience with Schwable Ones & Conti Competition tubs. For 25c I ran both at 90/100 F/R psi for a couple weeks and it felt really sluggish on climbs, like they were sticking to the ground. Put them back up to 110/120 F/R and bike feels more responsive and definitely faster. The Ones flatted on me like crazy though, really nothing to do with pressure. They're just very supple and puncture easily.

In comparison for tires that do better at low pressures, I run 25c Michelin Pro4 Endurance v2 clincher tires and they are supremely comfortable and fast at 85/95 F/R.

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Kayrehn
Posts: 1775
Joined: Thu Mar 24, 2011 6:06 pm

by Kayrehn

Cyclist magazine ran an article about tire pressure saying there's less chances of flatting at higher pressure. A few different sources all recommend 110psi for my body+bike weight (about 75kg) so I run that behind and 100 in front for my tubs.

964Cup
Posts: 195
Joined: Tue Dec 18, 2012 1:31 am

by 964Cup

+1 for the Ones being made of cheese. Five flats in the rear on Sunday over 246km (crap roads, lots of gravel washed in by the floods etc). Fortunately all caught by sealant, so no delays, although it wouldn't hold much above 60psi by the end; some Tufo Extreme seems to have sorted that, fingers crossed. May go back to Paves or switch to Arenbergs (quite fancy trying 27c). Found riding the tyre soft (60-80psi) quite unpleasant although I don't think it slowed me down - got some PRs in the last 50k.

It would be nice to ride the bike this thread is actually about, but it just won't stop raining. Shame we can't brexit from the climate instead of the union.

mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

Love you username. Do you have a 964 (911) Cup Car?

964Cup
Posts: 195
Joined: Tue Dec 18, 2012 1:31 am

by 964Cup

I did. Raced in the (UK) Porsche Cup in 2001 and the Porsche Open & Intermarque in 2002. Long sold, but the user name stuck.

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JKolmo
Posts: 654
Joined: Sat Feb 10, 2007 2:00 pm

by JKolmo

964Cup wrote:And the whole point of tubs is that they allow very high pressures.


Uuuhhh, quite the opposite. The whole point with tubulars is that they allow lower pressure than clinchers. And too high pressure gives you higher RR.

964Cup
Posts: 195
Joined: Tue Dec 18, 2012 1:31 am

by 964Cup

Bollocks. Sorry, but http://velonews.competitor.com/2014/12/ ... nce_355085 for example. Higher pressure = lower RR. Tubs allow lower pressures for e.g. Roubaix or cyclocross - because they're less likely to pinch-flat - but they also allow much higher pressures than clinchers for use in e.g. time trial or track. That's why track tubs have such high inflation limits, and why track riders often run at 180psi plus. The issue is not rolling resistance, it's traction efficiency. Because the velodrome surface is smooth, the tyre does not have to deform for traction, and does not need to absorb bumps without bouncing (and therefore losing traction). In road-riding you need enough compliance to allow the tyre to deform to the (much rougher) surface and absorb small bumps without bouncing you into the air. This is (one reason) why optimal tyre pressure varies with system weight. In mixed condition riding your tyre pressure choice reflects a balance between traction efficiency and compliance for poor surfaces and rolling resistance for smooth tarmac. That's why I run anything up to 140psi (23c) for Regent's Park laps, but was at 100F, 110R (25c) out in the sticks on Sunday.

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JKolmo
Posts: 654
Joined: Sat Feb 10, 2007 2:00 pm

by JKolmo

[emoji3]

UpFromOne
Posts: 1181
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

Denavelo wrote:Friends don't let friends ride Tufo tires!


So true :lol:

Denavelo
Posts: 437
Joined: Wed Apr 08, 2009 8:01 pm

by Denavelo

964Cup wrote:I did. Raced in the (UK) Porsche Cup in 2001 and the Porsche Open & Intermarque in 2002. Long sold, but the user name stuck.


964's are all the rage now... Known for being an oil leaker and easily found for $10k 5-6 years ago, but now you can't get a clean example for under $30-40,000... My buddy daily drives his RS America around, and my inner circle of buddies all have 964's.. I want a GT3 one day..
Rob English "Mudfoot" 29er | Focus Izalco Max | Firefly #194 Stainless XCR | Firefly #277 | Neilpryde Bura SL 11.9 | Crust Evasion Lite

964Cup
Posts: 195
Joined: Tue Dec 18, 2012 1:31 am

by 964Cup

I've given up on cars. Driving in the UK is unremittingly tedious, track days are full of idiots with more cash than talent and racing is too expensive. Anyway, I can't ever imagine looking out of the window on a sunny day and choosing car over bike. We have a Discovery for long trips and a Fiat 500 for city duties, and that's one too many already in my view. On the other hand I have 12 bikes, and that's at least four too few...

964Cup
Posts: 195
Joined: Tue Dec 18, 2012 1:31 am

by 964Cup

ETA - I had a mark 1 GT3 back in the day. Overhyped. Sound like a bag of spanners in a washing machine, the 996 body is too big to be really wieldy and the default suspension set-up understeers. The mark 2, and the various 997/991 derivatives are objectively "better" - which is to say faster and better handling on track, but they're increasingly inappropriate for road use - not because they're unusable, but because they're too good. By the time you're having fun, you're going way too fast for public roads. Get a 993RS - they're much slower, but far and away a better car. It's the only one of my long history of wasting money on automobiles that I actually really miss.

Denavelo
Posts: 437
Joined: Wed Apr 08, 2009 8:01 pm

by Denavelo

Ha you've said everything I've been telling LA guys about cars. 500-600hp is too much power out here. By the time you get close to the sweet spot of the rev range, you'll be in the back of a prius at a red light driven by a high school girl on her iphone. I'm finally at a point to get into another really nice car (911, GTR, etc). I've been reading online reviews for weeks on end, and I can't decide on a car for the life of me. I 'm just going to get a TDI Golf with roof racks and explore the US for the next few years with my road bike. The money invested in that will outweight the pricey 996 MK2 GT3 oil changes and constant wrenching.

I had a fully built Evo9 that put out 450hp. I got a ticket on the highway doing 150 in 5th gear, following a McLaren.. I sold that ticket magnet and got a M3. Hands down one of the best cars I owned, but now the M3 is seriously over priced and too electronic for my liking. They have like 500 suspension and driving mode combinations. INSANE! I kind of want a E90 series M3 with the booming V8, but the MPG will just kill my vibe.. I'll look hard enough for a clean 964 and keep the 3.6 modest and drive it on weekends and the TDI golf for daily duties.
Rob English "Mudfoot" 29er | Focus Izalco Max | Firefly #194 Stainless XCR | Firefly #277 | Neilpryde Bura SL 11.9 | Crust Evasion Lite

by Weenie


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junghwan
Posts: 2
Joined: Thu Jul 14, 2016 5:06 am

by junghwan

This is my dream Machine.....!!!!!

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