Diamante Pro radiale and a fish-tail issue

[Archibald]

Anyone using Vittoria's new radiale Diamante Pros? Or had a similar issue?

Feedback welcome, please...

I've had a pair since early August and put a few hundred k's on them, as well as racing on them.
I'm finding that the rear-end seems to "fish-tail" at speed. Most noticable when on the descents when beginning to pedal again. You know, when you discover you hadn't put it in a high enough gear and your cadence goes through the roof.
Once I feel the pressure on my feet again it seems to calm down, but I still need to push a high gear for it to settle, and even then I can still feel some movement of the rear wheel.
Have checked the frame for cracks in case that may be the cause, but everything appears to be sound...

Thoughts, ideas, experience...

[info that may matter: 2011 carbon frame, DT465 rims on ultegra hubs]

 

[FitSsikS]

When that happens to me it's because of my pedaling technique....or lack thereof.

Of course you are suggesting that it doesn't happen with other tires so it appears as though that (pedaling smoothness) may not be your problem.

 

[Bustedknuckle]

Anyone using Vittoria's new radiale Diamante Pros? Or had a similar issue?

Feedback welcome, please...

I've had a pair since early August and put a few hundred k's on them, as well as racing on them.
I'm finding that the rear-end seems to "fish-tail" at speed. Most noticable when on the descents when beginning to pedal again. You know, when you discover you hadn't put it in a high enough gear and your cadence goes through the roof.
Once I feel the pressure on my feet again it seems to calm down, but I still need to push a high gear for it to settle, and even then I can still feel some movement of the rear wheel.
Have checked the frame for cracks in case that may be the cause, but everything appears to be sound...

Thoughts, ideas, experience...

[info that may matter: 2011 carbon frame, DT465 rims on ultegra hubs]

Don't think it's the tires..Hub cones adjusted? Wheel true?

BUT put another tire on there to see if you 'feel' the same thing.

 

[winkybiker]

Might be a wheel balance issue caused by an out-of-spec tyre. The tyre may not be evenly seated on the rim. Have you tried switching to another tyre, or remounting that one?

 

[Archibald]

worked just fine with the GP 4seasons I had on over winter, but will reseat and try a different tyre.

Could this be a possible explanation?
http://www.cycletechreview.com/2012/reviews/vittoria-diamante-pro-radiale-tyre-review/

 

[ElChingon]

worked just fine with the GP 4seasons I had on over winter, but will reseat and try a different tyre.

Could this be a possible explanation?
http://www.cycletechreview.com/2012/reviews/vittoria-diamante-pro-radiale-tyre-review/

Well you're riding them, how true is that review in your miles/k's on them?

As for the fish tailing, how are you positioned on the bike when it happens? Leaning forward, standing, sitting on the tip, sitting near the back, hovering on the seat?

 

[avanti]

............
Could this be a possible explanation?
http://www.cycletechreview.com/2012/reviews/vittoria-diamante-pro-radiale-tyre-review/

This reviewer messed up his pressure conversions 60 psi is 4.1 bar, not 0.5 bar.

Anyway I read elsewhere that you have to match your tire and rim width for optimum performance.

 

[winkybiker]

worked just fine with the GP 4seasons I had on over winter, but will reseat and try a different tyre.

Could this be a possible explanation?
http://www.cycletechreview.com/2012/reviews/vittoria-diamante-pro-radiale-tyre-review/

That seems a plausible explanation. Does it fit with your experience? I won't be buying a pair.

 

[Archibald]

Raced on them again this weekend after checking the fit.
pumped to just over 125psi.
really seemed to feel like the road was greasy under the rear wheel when pedalling at speed. Felt fine as soon as I stopped pedalling and freewheeled.

afterwards I asked my mates to take it for a spin to see if they felt it too, but all are on a different pedal system to me...

I did notice another bike in the bunch have some rear wheel movement of a similar nature during the race, but didn't mark him well enough to find him afterwards and question him. (I fell of the back with around 9kms to go)

Well you're riding them, how true is that review in your miles/k's on them?

As for the fish tailing, how are you positioned on the bike when it happens? Leaning forward, standing, sitting on the tip, sitting near the back, hovering on the seat?

seated and can be either seated properly on the saddle or creeping forward on it. Usually leaning forward as you would for putting the hammer down.

That seems a plausible explanation. Does it fit with your experience? I won't be buying a pair.

it kind-of fits...
I haven't noticed any cornering issues of under or oversteering. It never feels wrong when cornering, only when pedalling at speed when it feels like the road is "greasy" under the back wheel.

 

[Stingray34]

125 psi is kind of a high pressure for aussie roads; tires at high pressue tend to slip more often. Try at 100psi and see if still gives trouble. Learnt my lesson with Vittoria tires, Contis all the way for me.

 

[Archibald]

125 psi is kind of a high pressure for aussie roads; tires at high pressue tend to slip more often. Try at 100psi and see if still gives trouble. Learnt my lesson with Vittoria tires, Contis all the way for me.

pressure range for the diamante is 120-145psi, so I'm just over the minimum.

and the tarmac of West Head rd where we race is schmick

 

[Bustedknuckle]

pressure range for the diamante is 120-145psi, so I'm just over the minimum.

and the tarmac of West Head rd where we race is schmick

Just for an update. I called the Vittoria distributor in the US and these tires, Diamante Radiale, have been recalled, in the US. Due to lack of stability and extremely short tread life..you may want to check with the place you got them to check with distributor.

 

[Archibald]

Just for an update. I called the Vittoria distributor in the US and these tires, Diamante Radiale, have been recalled, in the US. Due to lack of stability and extremely short tread life..you may want to check with the place you got them to check with distributor.

cheers for that!!

will have to check records, but reckon it was a chainreaction or wiggle purchase...

 

[Bustedknuckle]

cheers for that!!

will have to check records, but reckon it was a chainreaction or wiggle purchase...

That might be a problem, they 'may' self warranty but most of their stuff is gotten thru 'alternative' distribution channels. I doubt they can call Vittoria SPa and ask for guidance. BUT give 'em a call.

 

[BroDeal]

pressure range for the diamante is 120-145psi, so I'm just over the minimum.

Face*Palm

..........

 

[Archibald]

That might be a problem, they 'may' self warranty but most of their stuff is gotten thru 'alternative' distribution channels. I doubt they can call Vittoria SPa and ask for guidance. BUT give 'em a call.

wiggle[.com.au] came back saying they know nothing of a recall and are requesting the source...

i'm currently awaiting a response from Aust distributor and Vittoria themselves

 

[Archibald]

Can confirm that, there is no recall order anywhere for these tyres, according to Vittoria themselves.

... tires at high pressue tend to slip more often. Try at 100psi and see if still gives trouble...

It is a pressure issue, and after dealing with one of the original test riders, the recommendation for my weight is to run them at around 135psi (give or take 5psi).
It's to do with the construction and high TPI, which doesn't appear to go too well with the lower pressures...

 

[BroDeal]

Can confirm that, there is no recall order anywhere for these tyres, according to Vittoria themselves.

It is a pressure issue, and after dealing with one of the original test riders, the recommendation for my weight is to run them at around 135psi (give or take 5psi).
It's to do with the construction and high TPI, which doesn't appear to go too well with the lower pressures...

135 PSI?? How much do you weigh? A 120 kilos?

 

[Jeremiah]

135 PSI?? How much do you weigh? A 120 kilos?

It's Karelin. He's a beast on the bike also...

 

[Archibald]

135 PSI?? How much do you weigh? A 120 kilos?

far less than that, bike included.

it actually sounds like a plausible idea. Radial tyres for motor vehicles have steel belts in them to improve the side wall stability, so perhaps the increased pressure gives the radial bike tyres that extra "hardening" without using steel belts in them?
Radial construction isn't conventional bike tyre construction...

Who knows, I'll give it a shot and see how it goes. If it works, great... if not then I get rid of these tyres and move on.

Besides, I know some other folk running their tyres at 130psi+, and one guy who runs his tyres at 140psi.
might be too high for his rims, but he has no issues in being well at the pointy end come the finish line each month.

 

[avanti]

http://www.maxxis.com/Bicycle/Road-Racing/Radiale-22c.aspx
Maxxis also ha a radial racing tire - anybody riding these?

 

[BroDeal]

far less than that, bike included.

it actually sounds like a plausible idea. Radial tyres for motor vehicles have steel belts in them to improve the side wall stability, so perhaps the increased pressure gives the radial bike tyres that extra "hardening" without using steel belts in them?
Radial construction isn't conventional bike tyre construction...

Who knows, I'll give it a shot and see how it goes. If it works, great... if not then I get rid of these tyres and move on.

Besides, I know some other folk running their tyres at 130psi+, and one guy who runs his tyres at 140psi.
might be too high for his rims, but he has no issues in being well at the pointy end come the finish line each month.

Unless you weigh a ton, there is no reason to run tires at that pressure unless you are on a track. The tires will be hard as rocks. You might as well run on the rims without tires. Aside from being uncomfortable as hell, the tires will tend to skitter on rough pavement and road variations in corners. On non-ideal roads they will handle like crap.

 

[ElChingon]

Unless you weigh a tone, there is no reason to run tires at that pressure unless you are on a track. The tires will be hard as rocks. You might as well run on the rims without tires. Aside from being uncomfortable as hell, the tires will tend to skitter on rough pavement road variations in corners. On non-ideal roads they will handle like crap.

I guess we now have a reasoned decision on why it was fish-tailing so much.

 

[Archibald]

that's all fair enough, but, at 125psi these tyres don't feel all that 'hard'. I run the rubino pros I commute on at just over 100psi, and they feel harder. go figure...

i'm game to give it a try to see how things go at 135psi. maybe the guy from Vittoria who said he's been riding and racing on them for 2 years will be right, maybe he won't...

if running tyres at 125psi - 145psi makes for poor handling and an uncomfortable ride, why would you make a sell them? seems like a silly move on their part, no?

 

[winkybiker]

The recent move to lower pressures isn't for everyone. I run my 23mm Conti 4000s at 120psi to 125psi (I weigh 75kg). I don't find them harsh and simply prefer the feel of hard tyres to the "squidgy" feel of lower pressures.