Diamante Pro radiale and a fish-tail issue

[Archibald]

gave it a whirl at 135psi.

the rear tyre could still be flexed by hand and still had some of that fish-tailing effect.
Being out on the road without a track pump meant no ability to try to increase pressure and see how that went.
Lowered pressure with a quick press on the valve and things improved. was better than at 125psi, but had to be in the right gear. Any 'spinning' created issues going downhill or on the flat - uphill no problems with cadence or 'fish-tailing'.

Was noticably quicker at the higher pressures too, but on any uphill I still felt some tyre 'softness' (or 'flex' or 'bounce' or whatever you personally call that sensation) when out of the saddle. At 135 and just below, the tyres still weren't 'rock hard'...

no discomfort in ride though even on the rougher sections - still felt great to ride on when not fish-tailing.

so, some improvement, but it seems a like there's a narrow 'niche' or a 'sweet-spot' that needs to be found for best results.
Not sure I'm serious enough to want to go through all the messing about to find it and then mess about to stay in that 'zone'...

 

[Master50]

Late in the thread but we don't have a lot of experience with bicycle radial tires so I think some of the advice or common wisdom is not yet applicable to this technology. I am pretty sure that the pressures we like for bias lay up is different for radials. Although car technology I think tire pressures went down with radial tires?

 

[GeoffB]

I purchased a pair of these Radiale tyres and experienced this fish-tailing effect on dry roads on my first ride. The bottom bracket swayed from side to side and it scared me to the extent that I couldn't ride downhill as fast as my riding companions. I took them off my bike after the first ride and returned them to Ribble UK who had offered to refer them to Vittoria. When Ribble received them they just determined that there was no structural damage to the tyres and refused to give a refund because the tyres were used. The upshot is that these useless and dangerous tyres have been returned to me and I'm out of pocket for the cost of 2 tyres + 2 shippings. I've subsequently sent a message to Vittoria about my dissatisfaction and they haven't bothered to reply. I read somewhere that these tyres have been recalled in the US due to safety issues, but this is unverified. I've read mixed reviews about these tyres including one that was reasonably positive, but cautioned against using them in a bunch situation. And this is supposed to be a racing tyre. Well, my assessment is that these tyres are extremely dangerous and I'm perplexed that Vittoria continue to sell them to unsuspecting consumers. These tyres should be recalled world wide.

 

[GeoffB]

Oh, and I forgot to mentioned that tyre pressures, or lack thereof have nothing to do with the way that these tyres behave, it's all to do with the way that they're manufactured which is quite different to anything previously developed. You can pump them up as hard as you like and it won't stop them from fish-tailing. The effect is like riding fast on a deflated rear tyre.

 

[Archibald]

wiggle said they couldn't determine if it was wear or damage to the tyre, but still plumped up a voucher for (if i recall correctly) 40 quid.
Vittoria distributor replaced them with a pair of rubinos and a some inner tubes to round out the difference in cost. And this is after quite some consultation time and assistance.

As stated above, they calmed down a lot at the higher psi and when using a higer gear (ie; not spinning). Still felt a tad soft even at 140psi.
The front tyre was never an issue for me at around 125psi.
I raced with the rear at both 125 and 135psi with no major issue other than feeling uncomfortable in the few occasions I felt the rear flexing.
In the end, I got almost 900kms out of the rear, which was the first to wear through in 3 small places...

I've since moved to using Corsa Evos and they're effing great!

 

[Bustedknuckle]

I purchased a pair of these Radiale tyres and experienced this fish-tailing effect on dry roads on my first ride. The bottom bracket swayed from side to side and it scared me to the extent that I couldn't ride downhill as fast as my riding companions. I took them off my bike after the first ride and returned them to Ribble UK who had offered to refer them to Vittoria. When Ribble received them they just determined that there was no structural damage to the tyres and refused to give a refund because the tyres were used. The upshot is that these useless and dangerous tyres have been returned to me and I'm out of pocket for the cost of 2 tyres + 2 shippings. I've subsequently sent a message to Vittoria about my dissatisfaction and they haven't bothered to reply. I read somewhere that these tyres have been recalled in the US due to safety issues, but this is unverified. I've read mixed reviews about these tyres including one that was reasonably positive, but cautioned against using them in a bunch situation. And this is supposed to be a racing tyre. Well, my assessment is that these tyres are extremely dangerous and I'm perplexed that Vittoria continue to sell them to unsuspecting consumers. These tyres should be recalled world wide.

'Soft' recall in that Vittoria USA isn't selling them right now. Yes the non Radiale Diamante but not these. I suspect that the Vittoria tires at Ribble and other UK/MO places are getting there in 'non standard distribution channels', and they won't warranty, probably won't comment.

If Ribble called Vittoria USA they would hear about it but I'm pretty sure Ribble is stuck with these and really has no place to return them to.

Cavet emptor