Howard Millichap said:
Bolloxs. I found that on a site somewhere. Can't be arsed to find it again. If you lot want to risk your life that's your problem. Go do it.
So, while you can't be bothered to do a google search, you are prepared to go to much more significant effort and write to VOSA and enquire about a bike that, let's face it, you're never going to buy (and which wasn't, actually, the one at issue in this thread's first post)?

The fact that you did that tells so much about you!
I did bother my @rse to do a bit of searching and found the following:
The Regulations that apply are The Road Vehicles (Construction and Use) Regulations 1986.
Searching on them gives the following results:
From
http://www.police-law.co.uk/law/policelaw.nsf/0/158d1b65e849d5d780256baa005964b0?OpenDocument
The tyres 'shall be suitable having regard to the use to which the vehicle ... is being put ...'
and
'not a temporary use spare type (for use only if normal tyre fails and used at a lower speed)...'
About the 'best' I could find without getting a full copy of the regulations (which I couldn't find on the web) is from
http://www.etyres.co.uk/uk-tyre-law
Regulation 24 of the above regulations (the same regulations, Howard, not 'different' ones

) says how temporary spares can be fitted. Later on the page it says that temporary tyres can be used up to 50mph. This establishes a precedent; if temps are OK to 50mph (as stated on the tyre and wheel), why aren't Q-rated safe and legal when they can go much faster - irrespective of the vehicle's top speed?
This view would seem to be reinforced by other comments on that site saying, 'All tyres must have a service description (i.e. load and speed index). If the vehicle was to operate outside the service description indicated on the sidewall e.g. at a higher speed or overloaded then the tyres would be deemed to be unsuitable for the use, and a prosecution would follow.' And so it should.
So my points, unless you're still not getting it, are that it's not very impressive to state knowledge of regulations that confirm your point of view then storm off in a hissy fit when challenged.
Nor is it particularly helpful to assert that a situation is 'totally unsafe' when it quite obviously from a practical point of view and almost certainly from a legal point of view, is deemed safe. I remind you that, in the country in which those regulations apply, it isn't legal to exceed 70mph so the Q-rated tyres are never going to be challenged (legally). If you want to bring up the IoM, fine but it tends to prove my point rather than refute it because even there you can be had for exceeding the tyres' ratings when you're not exceeding the local speed limit. The system works!
But, all the while, at the heart of the argument is the truism that Cheesy Mike said in his post a while back: 'I also fail to see how a 98mph rated tyre could be considered unsafe on a bike that can only be used at a legal speed of 70mph in the UK. Anyone who rides at a consistent speed greater than 98mph long enough for their tyres to delaminate or blow has, IMHO, much bigger problems to face than how their tyres are going to perform.'
