Kumho Tyres - Anyone Else Tried?

[plasma99]

I've just replaced my four tyres and couldn't afford like-for-like Goodyears. 215/50/R17 seems to be an expensive size and so went for the more afordable Kumho Solus KH17s. I had Kumhos on a previous car and was quite impressed.

Anyway, the ride is very good with the new tyres and extremely quiet but the fuel economy is absolutely terrible. I've gone from 48-52mpg indicated to 42-44mpg indicated. OK, these new tyres have a low "F" rating for fuel economy but that is only slightly worse than the "E" rating for the tyres that were removed. I didn't think the rating would make such a difference anyway (maybe a few percent).

I was just wondering if anyone else has tried these tyres (KH17s) and if the fuel economy is likely to improve over time? P.S. I have tried the tyre pressures at 35PSi and now slightly over recommended at 36PSi.

[t-spiritpete]

Hi Pete,

I fitted a full set of Kumho Ecsta le sport KU39 215/50/17Y rated to mine earlier this year and up to now I have been very happy with all aspects of them., and the price was great.

Like most diesels right now your mpg will have fallen due to the cold weather, mine has even with the pressures at 35 psi.

Regards T S Pete.

[+Steve]

MPG will fall like a stone in this weather.

[plasma99]

Hi Pete,

I fitted a full set of Kumho Ecsta le sport KU39 215/50/17Y rated to mine earlier this year and up to now I have been very happy with all aspects of them., and the price was great.

Like most diesels right now your mpg will have fallen due to the cold weather, mine has even with the pressures at 35 psi.

Regards T S Pete.

Hi Pete,

I could have got KU39s for only £5 more per tyre. The only thing that put me off was the relatively high noise level (76dB). I assume this has not been a problem?

[t-spiritpete]

Much quieter than the Federal 595 SS that I had on the front before but the Goodyear NCT's on the back weren't too bad though. I do like the feel/feedback from the Kumho's especially in the wet as they feel well planted to the road, in saying that I'm not a boy racer and don't push them to where the limit may be. Hopefully when the weather gets warmer your MPG will go back up again. On a recent trip up to North Yorkshire and back mostly on the motorways I did manage 64 mpg but that was really trying hard to keep it in the magic 1800-2000 rpm zone, and yes the computer is as good as spot on for any non believers out there.

Regards TS Pete.

[Roker]

Interesting about the mpg in cold weather, does that just apply to diesels? as the air is colder it should be denser and give more power, mine is a petrol and my mpg is about average 42 at present, I seem to think it has to do with make of petrol.

[Jamesbelfast]

Interesting about the mpg in cold weather, does that just apply to diesels? as the air is colder it should be denser and give more power, mine is a petrol and my mpg is about average 42 at present, I seem to think it has to do with make of petrol.

You have to remember any internal combustion engine is actually a heat exchange engine whereby heat is converted in motion - the colder the weather the less heat gets converted into energy therefore making the engine less efficient hence the decrease in mpg.

You also have to consider if the air is colder it will have a little more oxygen content by volume but the oxygen sensors in the engine management system may alter the fueling to compensate. Contrary to popular belief there little point of throwing more oxygen in an engine without altering the fuel mix to suit.

[Whitewagon]

Back to the original posting, I have never used Kumho tyres on any car but they seem to have a good report from many forum sources. My first test drive in a nearly new Avensis was in a car fitted with the Goodyear OEM tyre and I was very impressed with the low road noise. The car I bought (for colour preference) is fitted with Bridgestone tyres and is not as quiet, though not bad compared to a lot of new style cars. It would be interesting to know other owners experiences on the noise factor of different tyres.

[plasma99]

Just as a follow up to this one, I have now used a second tank of fuel - average for the tank was 45mpg indicated (real is normally a bit lower). I take the point about cold weather but this is clearly down from the norm. I'm convinced the new tyres are having a detrimental effect on economy. I would be wary of Kumho Solus KH17s. I'm just hoping they will improve as they wear in.

[Druid Boy]

Have you doen the reset/new tyres fitted thing with your satnav? It may affect you fuel consumption readings due to the size of the new tyres (bigger circumference because they haven't worn down yet).

[Cyker]

I don't know what your usual winter vs summer mpg fluctuation is, but it's usually pretty bad for diesels as our engines need to run hot to extract the most power out of the fuel; With a cold engine, the engine block acts like a massive heat sink and a lot of the energy gets soaked up by the engine. It does give a bit more power once it warms up tho', like a free intercooler

It does affect petrols too, but not as much and they tend to warm up a lot faster as they waste a lot of energy as heat anyway (That's why petrol exhaust is so much hotter than diesel exhaust) and have much lighter engine blocks so the heat-sink effect isn't as bad.

re. tyres, the new tyre rating is best taken with a pinch of salt, esp. older models - I noticed the rating for my old CPC2's was not that much different from, say, some Firestone Multihawks, but from experience I know they were waaaay better.

The CPC5's I have now have a much better rating in everything but they are not significantly different to the CPC2's (If anything they seem to be wearing faster! ).

I'd hang on 'til summer and see how they do then but I reckon it'll get worse before it gets better - We don't normally get snow until Jan-Feb round 'ere!

[plasma99]

Have you doen the reset/new tyres fitted thing with your satnav? It may affect you fuel consumption readings due to the size of the new tyres (bigger circumference because they haven't worn down yet).

Mine doesn't have a SATNAV so I'm not sure it's possible to reset. I have compared my speedo with my portable SATNAV and the readings are 60mph indicated versus 58mph true. I think it was a wider difference before so I guess tread depth has made some difference. I have read that generally tread depth icreases rolling resistance so that may be a contributory factor.

[Steverav1]

What were the original dunlop sp3000 like for the tyre noise my spare is brand new and i need of some tyres so was going to get another depending what they are like

Cheers in advance

Steve

[plasma99]

What were the original dunlop sp3000 like for the tyre noise my spare is brand new and i need of some tyres so was going to get another depending what they are like

Cheers in advance

Steve

I've never had Dunlops fitted. The last were a set of Goodyears - they were OK on noise.