ronecc Posted September 1, 2012 Share Posted September 1, 2012 Bit long winded that subject title. I am looking for some wheel chocks/blocks that are curved, for parking up the motorhome for a few weeks. I have seen them advertised in the past, but am bu....ered if I can find any now. Has anybody any idea what words I should be punching into my search engine? They are supposed to stop the tyres flatting when stood for a while. Link to comment Share on other sites More sharing options...
sss Posted September 1, 2012 Share Posted September 1, 2012 try tyre cushions, http://www.ebay.co.uk/itm/CARAVAN-WHEEL-STORAGE-TYRE-SAVERS-PREVENT-FLAT-SPOTS-/200688301536 , tyre savers & tyre cradles Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 1, 2012 Share Posted September 1, 2012 GOOGLE on "tyre savers" (omitting the quotes). An example here (there are other makes): http://www.johnscross.co.uk/products/Fiamma-Wheel-Tyre-Saver-stops-Flat-Spots.html You should check that the 'curve' of your motorhome's tyres' circumference matches the curve of the tyre saver as my understanding is that these products are generally aimed at the caravanning community and motorhome tyres are often a lot bigger than those fitted to caravans. Frankly, if you only plan to have your motorhome static for just a few weeks, I think you will be wasting your money. If it were parked up for for several months and couldn't be moved at all during that period, it might be worth using tyre savers, but for a few weeks you could just inflate all the tyres to their maximum recommended design pressure and leave it at that. It would be a good idea to move the vehicle a short distance (say) every fortnight or so, just to transfer the load round the tread-band, but, if that's not practicable, I can't see it mattering. Link to comment Share on other sites More sharing options...
Guest pelmetman Posted September 1, 2012 Share Posted September 1, 2012 As someone who has had tyres go square as the MOT man said ;-)................a few weeks ain't nuffink.......6 months without turning a wheel did mine in :$........ But in my defense I was into boats at the time *-) Link to comment Share on other sites More sharing options...
ronecc Posted September 2, 2012 Author Share Posted September 2, 2012 Thanks for your replies everyone. I do not intend leaving it stood for months, that would be a waste of money. So maybe I will save more money and not buy any. Cheers all. Link to comment Share on other sites More sharing options...
Brian Kirby Posted September 2, 2012 Share Posted September 2, 2012 If it is of any help, I have read that flats were a much greater problem in the days of cross-ply tyres, and that modern radials are much less affected. I have left our van static for at least two months in winter, because I think that less of a potential problem than driving it on wet/salty roads, and have not noticed any unusual tyre noise when it was driven. In these cases the van has been completely unladen, so stands empty, and therefore a bit lighter. I assume that may contribute somewhat. The tyres are under 5 years old, so I can't say of older tyres might behave differently. Link to comment Share on other sites More sharing options...
T8LEY Posted September 4, 2012 Share Posted September 4, 2012 I've never been quite sure how a rubber tyre can become deformed, ie develop a flat section. Rubber is a thermosetting compound; once formed it can't be reformed. They'd be able to make new tyres out of old ones if it was possible. Is the claim actually apocryphal and irrelevant to modern tyre construction, as I think Brian has suggested, or is there another tyre component that's unable to stand in one place for long? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 5, 2012 Share Posted September 5, 2012 T8LEY - 2012-09-04 10:58 PM I've never been quite sure how a rubber tyre can become deformed, ie develop a flat section. Rubber is a thermosetting compound; once formed it can't be reformed. They'd be able to make new tyres out of old ones if it was possible. Is the claim actually apocryphal and irrelevant to modern tyre construction, as I think Brian has suggested, or is there another tyre component that's unable to stand in one place for long? Once a tyre has been fitted to an 'in use' vehicle it will be bearing a proportion of that vehicle's weight. This is stating the obvious and will be visually apparent as the tyre will be deformed from its basic round shape at the point where it contacts the ground (the tyre's 'footprint'). This deformation does not present a problem when a vehicle is in regular use as the load constantly moves aroung the tyre's tread area while the vehicle is being driven and, when the vehicle is stopped, the weight on the tyre's footprint is not there for very long. However, when a vehicle sits unmoving for long periods the deformation of the tyre that the vehicle-weight produces at the footprint can result in 'flatspots' forming, or even physical damage to the tyre's structure. Heavy duty, high performance, high speed-rated and racing tyres tend to have a 'memory' where they 'remember' their shape when the vehicle was last parked. A flatspotting problem can occur when such tyres experience big swings in temperature, or a vehicle has have been parked overnight in cold temperatures or parked for an extended period. As a tyre rolls, it goes from a relaxed state to a loaded state hundreds of times per mile. This constant deflection generates heat that makes the tyre more flexible. But once the vehicle has stopped, the area of the tyre in contact with the road flattens as it is pressed against the road's surface. This can generates flatspots as the tyre cools. Until the tyres warm up again, flatspots can cause a ride disturbance that may be felt for the first few miles of driving. Flatspotting can be temporary, with the tyre recovering its round shape as the moving vehicle warms up the tyre. (I remember a report in "Car" magazine (many years ago) of a Lotus Carlton on test that developed tyre flatspotting temporarily after being parked for just a few hours overnight. The flatspotting could not only be felt when the car was first driven the next day, but heard too.) In more severe cases, the tyre's 'memory' produces permanent flatspotting that destroys the vehicle’s ride quality. Cold ambient temperatures make rubber compounds stiffer, increasing their tendency to flatspot, and the longer tyres remain stationary the better they remember their shape when the vehicle was last stopped. Park a motorhome unmoving for several months outside during the winter and there's a reasonable chance permanent flatspotting will result. Having said all this, I don't consider the adverse effect on ride quality of permanent flatspotting as the primary risk for the tyres of a motorhome that is static for an extended period. The big risk if that the tyres will be structurally damaged by the long-term flattening effect the weight of the vehicle places on the footprint. This can cause localised cracking within the footprint area and, if the cracking is deep within the tread pattern, it may well remain unnoticed. The Caravan Club recommends that caravan wheels be removed if a caravan is to be long-term stored, and I've seen a tyre from a caravan unused for many months with just the type of within-tread cracking I've just mentioned. When it's known that a motorhome won't be used for a long while, removing its wheels, or supporting the vehicle on axle-stands, won't normally be a practical proposition. Inflating a motorhome's tyres to their maximum design pressure should help to combat the continuous load being placed on them, and moving a motorhome occasionally to avoid the load always being on the same small area of the tyre is definitely advisable. The cradling effect of 'tyre-savers' should be beneficial, but (as I suggested earlier) there would be a need to match the tyre-saver to the tyre size. If a tyre were too large for the tyre-saver, the lateral 'ridge' at each end of the tyre-saver's contact area would dig into the tyre and, overall, this might result in more harm than good. Link to comment Share on other sites More sharing options...
T8LEY Posted September 5, 2012 Share Posted September 5, 2012 Derek Uzzell - 2012-09-05 9:51 AM T8LEY - 2012-09-04 10:58 PM I've never been quite sure how a rubber tyre can become deformed, ie develop a flat section. Rubber is a thermosetting compound; once formed it can't be reformed. They'd be able to make new tyres out of old ones if it was possible. Is the claim actually apocryphal and irrelevant to modern tyre construction, as I think Brian has suggested, or is there another tyre component that's unable to stand in one place for long? Once a tyre has been fitted to an 'in use' vehicle it will be bearing a proportion of that vehicle's weight. This is stating the obvious and will be visually apparent as the tyre will be deformed from its basic round shape at the point where it contacts the ground (the tyre's 'footprint'). This deformation does not present a problem when a vehicle is in regular use as the load constantly moves aroung the tyre's tread area while the vehicle is being driven and, when the vehicle is stopped, the weight on the tyre's footprint is not there for very long. However, when a vehicle sits unmoving for long periods the deformation of the tyre that the vehicle-weight produces at the footprint can result in 'flatspots' forming, or even physical damage to the tyre's structure. I think you've got it there Derek. It's the structure that's damaged in some way because I still don't see how temperature can effect a material that sets with the application of heat. Old tyres are chipped for playgrounds for the protection of children not reformed for products for the protection of adults. Link to comment Share on other sites More sharing options...
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