Tyres - NOT WINTER RELATED
Discussion
Im after a bit of a sence check here chaps. I need 4 new tyres on the mrs's X3 - the tyre size is 235/50/18 and its recomended to have a V rated tyre on, whic means the choice is somewhat limited and expensive.
As the X3 cannot exceed the 130mph limit for H rated tyres, I was thinking of getting some of these instead, as the choice is much better and they are substantially cheaper.
So my question is, am I missing something by judging just on the speed element of the rating and is this likely to be dangerous?
As the X3 cannot exceed the 130mph limit for H rated tyres, I was thinking of getting some of these instead, as the choice is much better and they are substantially cheaper.
So my question is, am I missing something by judging just on the speed element of the rating and is this likely to be dangerous?
Codswallop said:
I can't see how a lower speed rating would be an issue if all the other parameters are met and if you do not intend to exceed the speed rating of the tyre.
The insurance co. may have other views however...
Nope - check with them this morning, as long as the load rating is the same they are fine (I was suprised by this). The insurance co. may have other views however...
Could it be related to the weight of the vehicle? Running at higher speeds generates more heat, and logically an X3 running on those tyres will generate more heat than say a lighter 1-series running on similar tyres.
So perhaps they recommend the V-rated tyres for those reasons? Either way, I'm not sure I would want to deviate from what is recommended.
So perhaps they recommend the V-rated tyres for those reasons? Either way, I'm not sure I would want to deviate from what is recommended.
Dr Interceptor said:
Could it be related to the weight of the vehicle? Running at higher speeds generates more heat, and logically an X3 running on those tyres will generate more heat than say a lighter 1-series running on similar tyres.
So perhaps they recommend the V-rated tyres for those reasons? Either way, I'm not sure I would want to deviate from what is recommended.
Surely that would be load rating though? So perhaps they recommend the V-rated tyres for those reasons? Either way, I'm not sure I would want to deviate from what is recommended.
If the insurance co is happy for you to change speed rating down as long as you keep load rating value the same then go for it.Some of the speed ratings are ridiculous and just a blanket cover.
My 320d had tyres rated to 155 mph on it,every tyre place will reccomend these tyres,but yet the top speed is something like 130-135 mph and probably lucky with a good wind behind it to see that.
Same as when I swapped runflats off,Insurance company couldn't give a toss as long as the speed rating was at least V and load ratings the same or higher.
My 320d had tyres rated to 155 mph on it,every tyre place will reccomend these tyres,but yet the top speed is something like 130-135 mph and probably lucky with a good wind behind it to see that.
Same as when I swapped runflats off,Insurance company couldn't give a toss as long as the speed rating was at least V and load ratings the same or higher.
Make sure the load index is correct.
Speed rating doesn't matter - I had a lease company order Kwik-Fit to put lower speed rating tyres on my company car. I thought I'd soon put a stop to that by calling our isnurance company. They couldn't have cared less. The girl said "you can't go over 70 anyway"!
Speed rating doesn't matter - I had a lease company order Kwik-Fit to put lower speed rating tyres on my company car. I thought I'd soon put a stop to that by calling our isnurance company. They couldn't have cared less. The girl said "you can't go over 70 anyway"!
Deva Link said:
Make sure the load index is correct.
Speed rating doesn't matter - I had a lease company order Kwik-Fit to put lower speed rating tyres on my company car. I thought I'd soon put a stop to that by calling our isnurance company. They couldn't have cared less. The girl said "you can't go over 70 anyway"!
This is usually the attitude from insurers, in my experience. You really mustn't change the load rating, keep it the same or better than manufacturer's spec, but speed rating is fine. If you have one above the car's Vmax, what can you possibly have to worry about?Speed rating doesn't matter - I had a lease company order Kwik-Fit to put lower speed rating tyres on my company car. I thought I'd soon put a stop to that by calling our isnurance company. They couldn't have cared less. The girl said "you can't go over 70 anyway"!
+1 for Camskill's service, often the best price for performance tyres too. You may, however, want to have a look on Lovetyres too, though - for some things they are incredibly cheap.
mike325112 said:
Surely that would be load rating though?
I was under the impression that load rating was all related to the physical construction of the tyre. A higher load rating means more sideways force on the tyres sidewalls during cornering, and also more extreme loads on the front tyres during heavy braking. Tyres with a higher load rating have a stronger sidewall and general tyre construction.Speed rating relates to the sustained running at the stated speed... Since higher speeds generates more heat, higher speed rating tyres have to be able to withstand higher temperatures without any delamination of the tyre. Since the X3 will weigh more than a standard car running similar tyres, it will generate more heat through its tyres than a standard car, and thus a higher speed rating may be required.
Of course that might all be crap, but I would not want to risk it.
Had a similar issue with the mrs tdi Golf. All tyres are V rated (even though car is only a hatchback so maybe not a weight issue). Top speed of the car is 120 mph and as it is an older car it can barely crack 110 mph (tried it whilst driving in the fatherland). Michelins/Contis were significantly more expensive for its 16 inch wheels. Local tyre place said I could drop it down to H rating but recommended I used a decent branded tyre if i did that.
Dr Interceptor said:
I was under the impression that load rating was all related to the physical construction of the tyre. A higher load rating means more sideways force on the tyres sidewalls during cornering, and also more extreme loads on the front tyres during heavy braking. Tyres with a higher load rating have a stronger sidewall and general tyre construction.
Speed rating relates to the sustained running at the stated speed... Since higher speeds generates more heat, higher speed rating tyres have to be able to withstand higher temperatures without any delamination of the tyre. Since the X3 will weigh more than a standard car running similar tyres, it will generate more heat through its tyres than a standard car, and thus a higher speed rating may be required.
Of course that might all be crap, but I would not want to risk it.
I would think the tyre construction would be based around a combination of the speed and load ratings, therefore a higher load rated tyre of the same speed rating would be better able to withstand the heat build up than a lower load rated tyre. Similarly a higher speed rated tyre of the same load rating should be better able to withstand the heat build up than a lower speed rated tyre. Otherwise there would be no point in having both.Speed rating relates to the sustained running at the stated speed... Since higher speeds generates more heat, higher speed rating tyres have to be able to withstand higher temperatures without any delamination of the tyre. Since the X3 will weigh more than a standard car running similar tyres, it will generate more heat through its tyres than a standard car, and thus a higher speed rating may be required.
Of course that might all be crap, but I would not want to risk it.
Dr Interceptor said:
I was under the impression that load rating was all related to the physical construction of the tyre.
The load rating is the weight (maximum service load in Goodyear speak) that the tyre can supporthttp://www.goodyear.eu/uk_en/tire-advice/tire-info...
Deva Link said:
Make sure the load index is correct.
Speed rating doesn't matter
First point is correct. Second point is nonsense.Speed rating doesn't matter
Construction and Use regulations stipulate that a replacement tyre must meet or exceed the original load/speed indices of the factory tyres.
Whilst the car may not exceed a terminal speed of 130mph, it is capable of exerting forces upon the tyre that require it to have such a rating in the first place - whether that be through acceleration, deceleration, cornering forces etc.
Frances The Mute said:
Deva Link said:
Make sure the load index is correct.
Speed rating doesn't matter
First point is correct. Second point is nonsense.Speed rating doesn't matter
Construction and Use regulations stipulate that a replacement tyre must meet or exceed the original load/speed indices of the factory tyres.
Whilst the car may not exceed a terminal speed of 130mph, it is capable of exerting forces upon the tyre that require it to have such a rating in the first place - whether that be through acceleration, deceleration, cornering forces etc.
stemll said:
Link (can't find Regulation 25 online, only the amendments)? Very common for winter tyres to be a different speed rating.
It is, but we're not talking about winter tyres.I doubt you'd find much on C&U on t'internet as they're controlled documents - so you'd have to pay for a copy. Disclosure issues notwithstanding.
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