veloflex corsa 25 : tyre pressure?

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Delorre
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Joined: Sat May 24, 2014 12:09 pm

by Delorre

What tyre pressure do you run with those tyres? I've fitted them to a pair of bora 35 (clincher of course) with 105 psi in them. Regular extralite Michelin innertubes, not latex. I weight 72 kg. Veloflex and Vittoria get a lot of rave concerning ride quality vs f.ex conti 4000s. But, after a few rides, I can only conclude that the ride quality of those corsa's is not great at all, and certainly not better as GP4000s 23mm (also fitted to a wider 25mm rim, 30mm high and same pressure).

Do you advise dropping some pressure? On the sidewalls, the range is 6 to 9 bar (90 - 130 psi), so, I'm already on the lower part of it. Or are my Bora's overly harsh? Combined with a fairly harsh riding Scott Addict 2014, the current setup is not fun at all on all but perfect roads.

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nlouthan
Posts: 188
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Location: SF Bay Area

by nlouthan

I'd go down on pressure for sure. I'm 80kg at the moment and I usually ride 90f 95r.

Wingnut
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Joined: Sat Jun 23, 2007 12:41 am

by Wingnut

I'm 88kg atm after several operations and ride at 100psi so yes go lower...

JimV
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Joined: Tue Apr 05, 2011 6:57 pm
Location: Chicago

by JimV

Be careful with Veloflex's and carbon rims. Veloflex has a soft not recommended for carbon rim warning. They had been my favorite tire for many years. The hook on a carbon rim tends to be sharper than an aluminum rim. Over time the hook starts to cut the cotton of the sidewall. If you keep a close eye on the tire it will develop a bump in the spot that has been weakened before a catastrophic sidewall failure. A teammate of mine stopped in the teams shop and was going to get some tires and the owner of the shop told him that Veloflex did not recommend them for use with carbon rims. I had a few blowouts but had always assumed something had cut the sidewall. I then did a test on a tire that I noticed had a bit of a bubble, I pumped it up to 100psi and set it outside in the sun. Within a hour or so the tire popped in the spot that had the bubble. When I looked at the tire it was easy to see that the fabric of the sidewall was cut right at the edge of the hook. Challenge tires have the same problem. As much as I would like to buy Italian and not sweat shop Taiwan, Vitoria's have a reinforced bit of fabric around the bead that neither of the Italian tires do.

I weigh about the same as you and run 95-100

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Calnago
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by Calnago

I've seen Continentals warning as well re the same thing. I guess a question to ask would be whether or not your carbon rims have a sharp edge on the hook or a smooth rounded one.
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sychen
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by sychen

Just a bit(kilo or 3 depending on dinner) lighter than you but on narrower Zondas, i find it definitely better than GP4000 (original, haven't tried V2) at 100psi.. but noticialbly smoother at 80psi... though never pinch flatted.. i always pump it back up to 100psi every week more for peace of mind when out at 5am.

What annoyed me more about the GP4k is really the shape of the tire... its not really round, its more oval in shape so when leaning over in to a corner there is a harsher/ less confident transition. Not to say i will lose traction but it feels like it... the open tubular carcass of the Veloflex is very even and consistent... never a doubt when deep in a corner at 60km/h.

Is a GP4k different in feel on a wide rim.. probably.. but I cannot say for sure without trying it... and also which version you have.

Lots of people swear by them.. go with what works for you... Veloflex for me... plus its cheaper locally in a pinch.

FilmAt11
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Joined: Sun Jan 09, 2011 2:35 am

by FilmAt11

90/95psi @ 72kg, unfortunately had to stop riding these great feeling tires because of too many flats from cuts in the tread on my local roads.

Delorre
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Joined: Sat May 24, 2014 12:09 pm

by Delorre

I've been running 90f & 95r for a couple of weeks now, and the real harshness is gone. What remains I think is the vertical stiffness of the Addict combined with fairly stiff Bora's. Will keep them until worn and try the trusted (for me) Conti combi to compare.

Back to the Veloflex Corsa's : after 1000 miles on them, not 1 cut or flat, good thing! I just wonder, when are they considered as 'worn'? When the diamants are gone in the middle (this is almost completely the case at the rear already), or at a later stage? Do they wear square like conti's or not? Do you switch front and rear from time to time to achieve an egal wear at the end of their life? Maybe basic questions, but I've been running Conti's only for the last 10 years or so, and they have 'wear holes' in them, and wear square, so easy to see when they should be binned ;-)

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Calnago
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by Calnago

You've got some good mileage on them already but it really depends on when you feel it's time. How risk averse are you. There are no "wear markers" like on Conti's and any tire will wear somewhat square, but I think given that Conti clinchers begin life with a little bit of an egg shape versus the Veloflex which are more round, that you might expect a bit more squareness on the Contis with wear, but that depends on pressure too. Or, just ride 'em till your next puncture and then bin 'em.

Here's a Veloflex Carbon tubular that I destroyed in an emergency stop when a pedestrian stepped out in front of our group and the guy in front of me slammed on his brakes and I had to do same. Didn't realize what had happened at the time until after lunch when I got back on and noticed a bit of a lumpy ride. Held till I got home and was promptly replaced. Almost a brand new tire as well. Oh well... I think this pic is good for showing the various layers in a Veloflex tubular, and it's probably similar in their clinchers I would guess. I'm thinking that last layer shown is the very last before the latex tube...
Image

Also, here's what I found stuck in an almost new Arrenberg after a ride and was sure that upon removing a burst of air would follow. But nope, even though there was probably as much metal length inside the tire as you see outside, it must have slid in between the latex tube and the casing without puncturing. Amazing... wonder if a butyl tube would have been so lucky. No idea.
Image

Anyway, I'm really impressed with not only the ride of Veloflex but with their durability as well, at least when compared to something like Vittoria which, for me at least, would cut up every time I looked at them sideways. In winter I've been using Conti Comps but take something else as a spare. Would hate to try and stretch a conti tubular (even a used one) on a rim when my hands are freezing cold and wet. I don't even like doing it when they're warm and dry, but I do like the Comps in the foul weather.
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nlouthan
Posts: 188
Joined: Mon Jan 31, 2011 2:41 am
Location: SF Bay Area

by nlouthan

I'll usually ride rear tires until cords are showing. If staying with the same brand/model I move the old front tire to the back and put the new one on the front.

I've taken scissors to several tires when I thought they were worn out only to find that there was still a ton of rubber left.

Skunkworks
Posts: 60
Joined: Wed Jan 13, 2016 12:25 pm
Location: South Korea

by Skunkworks

Vittori developed simple smartphone application that decides how much pressure you need.

Search vittoria on app store and market ;)
you can select weather, weight, etc.

garlet
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by garlet

{0.33x2.2x(weight.include bike)}+43.33

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DartanianX
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by DartanianX

Where did this come from? ^^^

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