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7 Feb 2010, 16:18 (Ref:2628600) | #1 | ||
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Dunlop tyres (old)
How long are Dunlop CRs good for?
I have a set that are lightly used by the previous owner (1 race, HSCC Oct Donington 2008) and I'm wondering if they'll be ok for at least the start of this season. Expensive bits of kit, so I'm hoping I dont need a set of 4x boots to add to the long list! They dont seem hard |
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7 Feb 2010, 16:45 (Ref:2628612) | #2 | ||
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If they are only 2>4 years old they should be fine,depending on if they were stored properly,IE,out of the elements. They will possibly need a bit of coaxing back to life,heating through, though.
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7 Feb 2010, 16:48 (Ref:2628616) | #3 | ||
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Mmmmm, best you get a new set and I'll take the old ones off your hands to save you the recyling fee. They are 5.50 x 14 Ls, I presume..............
Their life has got something to do with how many heat cycles they have been through, but mine seem to wear out before that gets to be an issue Yours sound fine for this season and maybe more but any idea how old they were before first used? |
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7 Feb 2010, 16:50 (Ref:2628619) | #4 | ||
The Scarlet Pimpernel
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They deteriorate and best to replace.
One of ways to make car go faster ,new tyres and one of cheaper ways. |
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7 Feb 2010, 17:16 (Ref:2628643) | #5 | ||
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Always been in a warmish garage on their side (on wheels) under a dust sheet since I took them off the car.
I've only seen one race entry with my car's name on it since the previous owner (a chap who works for Hall and Hall) converted it from a rally car, so probably only once. They look very good, heaps of tread, but I was aware that they'd not been used for a while. Just in case, how much are a set? (yup, 5.5x14L) I may try them at Snetterton in March and see if I go backwards into a corn field....! Thanks chaps! Simon |
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7 Feb 2010, 17:30 (Ref:2628649) | #6 | ||
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I don't know about these particular ones but most road tyres have a date on them if you know "what" to look for.
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7 Feb 2010, 17:54 (Ref:2628663) | #7 | |||
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Quote:
Last set I got in '08 were £150 + vat each. They are just about 'slick' now..... |
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7 Feb 2010, 18:58 (Ref:2628714) | #8 | ||
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Well we'll see how they shape up in a few weeks. I'd rather not spend £600 just yet. Expensive business all this racing rubbish isnt it!
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7 Feb 2010, 19:06 (Ref:2628726) | #9 | ||
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I have a few 8 to 10 year old 008 Yokos, would they still be safe to use?
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7 Feb 2010, 19:23 (Ref:2628740) | #10 | ||
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[QUOTE=Mike Bell;2628616]Mmmmm, best you get a new set and I'll take the old ones off your hands to save you the recyling fee. They are 5.50 x 14 Ls, I presume.............. QUOTE]
?????? Whats left after youve burnt em is generally scap, n fits in councils' bin |
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7 Feb 2010, 19:27 (Ref:2628742) | #11 | ||
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7 Feb 2010, 19:29 (Ref:2628745) | #12 | ||
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I am afraid I simply cannot afford to keep replacing my Dunlop Formulas at £150 a pop plus delivery and fitting and VAT so maybe sacraficing a second or so but its either that or I dont race end of story!
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7 Feb 2010, 19:43 (Ref:2628756) | #13 | |||
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Quote:
£156 + Vat I reckon that's £733 assuming you can get the fitting and balancing in with the tyre price. Certainly is expensive this racing lark! On the age versus heat cycles versus wear topic; what is the expected lifespan of a set of Dunlop Rs. So for example, presumably if you run multiple short events the heat cycle fatigue will do the tyre in before the tread wears out? |
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7 Feb 2010, 20:03 (Ref:2628775) | #14 | ||
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Well that's fine then.
A couple of seconds really wont matter when the engine only gives 120 at the flywheel and the driver doesnt know his arse from his elbow!!! |
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7 Feb 2010, 20:04 (Ref:2628777) | #15 | |
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safety is paramount, however well stored they do keep a few years, I'm no different to many and try and get the best/most out of them, however I've looked at mine and binned them with loads of tread . . . I don't want to crash and burn!
I shred fronts (1-6 hours depending on circuit etc) but don't have the grunt to kill rears before the walls start to crack . . although I'm still working on that, (legally!) I generally do at least a set of fronts or 2 per year and a set of rears every 18 months depending on how much I race, and thats not a lot compared to many. they're not 'cheap' and I tried bulk buying to save, a futile effort, however, as John says, they're one of the cheaper outlays in the grand scheme of things, and your derriere is on the line . . . .like a crash helmet . . . . how much is yor head worth! |
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7 Feb 2010, 20:09 (Ref:2628780) | #16 | ||
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Do the second half of the race in reverse Zef?
Al,these tyres are the Dunlop Historic type,'Proper Tyres' not the loads of grip for wimps type. |
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Living the dream,Chief instruktor and racing on the worlds best circuits-The Nordschleife and Spa.Getting to drive the worlds best cars-someone has to do it, so glad its me. |
7 Feb 2010, 20:12 (Ref:2628781) | #17 | ||
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7 Feb 2010, 20:22 (Ref:2628783) | #18 | ||
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Loads of grip!!!! I tel you this they used to have but now they are made in another country they are seriously crap infact so much worse than the old ones there was talk of redoing the lap records!
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7 Feb 2010, 20:36 (Ref:2628794) | #19 | |
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As tyres age, they lose grip as the 'rubber' naturally hardens. This can be accelerated by exposure to ultra violet light from the sun, some artificial lights and arc welding.
The dangers lurk within, and a hard tread compound (which can be detected by a durometer and may be measured in slower lap times) is only one sign of the aging damage that may exist within the tyre construction and the risk that involves. Please read the following and then decide: Tyre Aging Rubber compounds used in tyres contain anti-oxidising chemicals that help to slow down the natural aging process of untreated rubber. However, tyres do deteriorate with age, which increases the risk of tyre failure, and there are many ways in which this can be spotted: · Cracking/crazing on the side wall of the tyre, caused by its flexing · Distortion of tyre tread · Deformation of the carcass of the tyre There will also be a deterioration of the ride quality caused by vibrations through the tyre. This may signify the tyre’s performance has been affected by age and should be investigated as soon as possible. All tyres that display signs of aging should be removed and not put to further use. Tyres that have been in storage should not be placed into use if they are over 6 years old, from their date of manufacture. When a tyre has been in use, the effects of aging are lessened to a degree, but such tyres should be replaced after 10 years. The effects of aging can be brought about prematurely in several conditions. Tyres fitted as spare wheels or used rarely as when fitted to caravans and trailers may age prematurely. If tyres on caravans or trailers are not in regular use, then they should be inspected before every journey. Tyre storage issue Currently the tyre industry is being asked to consider "expiration dates" on tyres as evidence continues to mount that "new" old tyres (i.e., spares, etc.) are catastrophically failing and causing deaths and injuries in the US. Documents from the tyre industry and its associations indicate tyre age and storage is a safety-related problem that potentially affects hundreds of thousands of spare tyres sitting under trucks and in trunks, or tyres that are stored for long periods, often unattended for years. Because of the lack of industry guidelines, tyres with acceptable tread depth and no visible signs of defects are finding their way into service regardless of their age. Scientific and statistical research from Europe have substantiated tread separation problems associated with aging tyres yet little has been done by the industry to assure consumers are fully aware of their recommendations to replace tyres that have aged beyond six years. |
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7 Feb 2010, 20:40 (Ref:2628797) | #20 | ||
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I cant see many race tyres being over 5 years old though, although I do have some wets and slicks in the shed that are way older.
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7 Feb 2010, 20:53 (Ref:2628804) | #21 | |
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the CR's have fantastically fragile walls . . . . I had brand new tyres when I went to rollers about 4 years ago, the car moved sideways a gnats, rubbed the wall . . .I'm sure its 'fine', but I'm scared of it, scrapped.
MoD world is safety critical, Wise. grips irrelevant when you have a blow out. |
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7 Feb 2010, 20:55 (Ref:2628806) | #22 | |
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I recall a conversation from my karting days about the effect of arc welding on tyres - the guy I was speaking to had bought a set of soft compound tyres about 6 months before the race we were in and had stored them with his kart at work, a metal fabrication business. The 'new' tyres were hard as nails and pretty much useless. I'm no chemist, but I think this was to do with ozone created by the electrical discharge.
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7 Feb 2010, 21:01 (Ref:2628810) | #23 | |
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Proper suppliers have to store rubber in UV resistant packaging if they're not fast moving stock items at least . . . safety critical items have a shelf life.
would you take a risk on a 2nd hand 'geronimo' ? |
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7 Feb 2010, 21:47 (Ref:2628837) | #24 | |||
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Quote:
I'll see how it goes. I really don't think they are dodgy but wanted to ask folks opinions because they rather important things to be in good condition after all. I cant physically afford 4 new tyres at 700 notes right now if I want to do at least one or two races this side of June. If they seem dodgy on the Snetterton test day...well I'll just have to wait until later in the year won't I. Last edited by skentellytubby; 7 Feb 2010 at 21:57. |
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7 Feb 2010, 22:19 (Ref:2628866) | #25 | |
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If you phone dunlop technical with the serial nos off the tyres they will tell you how old they really are .
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