From Conti SCII to Kumho KU31

[Chris GB]

Hi to All

Have just had fitted 4 Kumho KU31 tyres on standard Fabia vRS rims. Size is 205/45 R16 87W. First impressions are that they are a little quiter and less harsh than the Continental SCII were when new. Sidewalls seem stiffer than the Contis when new as well.

Looking at and prodding the sidewalls of the tyres before fitting, it is clear that they have a very small and firm (almost undetectable) comfort band in the sidewall. This compares favourably with the softer and around 3/8 inch comfort band on the SCII. Rim protection is not as deep as the Conti SCII. There is a lot more lug in the tread around the outer edges of the tyres as well. The void area looks to be greater than on the Contis. The compound feels softer than the Contis when cold and the tyres seem to build up heat and get working quickly.

Wearing a little of the mould release agent off the tyres, they are starting to "come in" after around 100 miles. Initial impressions are that the tyre needs a bigger slip angle to generate cornering force than the SCII, so more steering is required to get around a given corner. As a result, turn in feels subjectively slower, although once turned in, the tyres more rigid structure makes it feel more positive. This increased need for slip angle may just be a result of the tyres newness.

The tyres are still too new to start leaning on them heavily, but a quick go at hoiking it into a corner and loading the back up gave a fairly big sideways attitude through the corner, followed by excellent front end grip under power on the way out allowing the car to keep the back end loaded. On the downside, considerably more steering had to be used to do this than the SCII, so therefore, less optimal balance is achieved. I will give them another two or three hundred miles to scrub, which may well improve matters.

The stiffer sidewalls seem to suit the standard damping very well. The SCII sidewalls went from soft to baggy after 5000 miles and this made the tyres springy and seemingly bouncy. The KU31 seem to be much better in this respect and are better suited to the microdamping properties of the standard setup. Wheel patter over broken surfaces is hugely improved. The primary ride is also improved with the car / tyre system combining to feel better damped than it ever did with the SCIIs.

So far, so good. Will add to the review as the miles go on and as I get to try them in the wet.

Hard cornering and wet weather performance at 300 miles update

OK, 330 miles total mileage on the KU31 and it starts to chuck it down with rain. In the interests of science and for you lot, I went out for a little tyre testing tonight. Well I did expect to report that alas I got what I paid for (£53.95 each). However, it would seem I got considerably more than I paid for.

Dry performance:

The tyres have scrubbed in now and have settled down nicely. Turn in still requires more lock to be applied than the Conti SCIIs but once turned in, the tyres provide a stable and accurate response. Steering feel is pretty good and you are aware of the amount of grip you are using. The car does feel a little loose at the back end, but this is because the tyres take on a more sideways stance to corner than did the SCIIs. So when you turn in, it feels a little vague at the back. Lean on it a bit more, turn in a bit harder, get the back starting to swing and apply some gas to balance and the rears dig in nicely. You end up going a bit more sideways than is immediately comfortable in a FWD car, but as long as you have power left to drag it straight should the back start to let go, it all seems very "right". I would say that outright lateral grip is a little better than the SCIIs. Certainly, once loaded into the corner, the car is more resolutely stuck on its line where the Contis would have the car loading and unloading the rear end as the front bounced around, on these it just stays pinned.

Braking grip is another area where the Kumhos have a slight advantage. Doing emergency stops with a customer today, it was quite obvious that the ABS cuts in later on these tyres. Straight line traction is also improved over the SCII.

On higher speed corners, stability compares favourably with the SCIIs. The stiffer sidewalls inspire more confidence and you get more feel of road surface and camber changes.

Once the limit of adhesion is breached, the higher slip angles and speeds will make this car on these tyres a little less easy to catch than the SCIIs, but the rear end seems to let go first consitently and more gas seems to just haul it back into line. It is by no means snappy though and communicates its intentions well.


Wet performance:

In normal driving, the tyres give a very surefooted and positive feel. There is again plenty of feedback when turning and they feel good under braking and acceleration. Upping the pace to push on a bit harder, the stable feel stays. A trait carried over from the dry handling is the increased slip angle required to achieve turn in over the SCIIs. Again, this manifests itself as a feeling that the whole plot is going to go horribly sideways, but agian, lean on it more and the grip is there, just more sideways in attitude. Actual grip levels are definately higher than I have ever had with the SCIIs in the wet.

Once past the limit of adhesion, the tyres break away in a less progressive fashion than the SCIIs. Where the Contis would start to drift and rumble across the surface quite early on, the Kumhos are still digging in. However, once they do start to let go, you feel it more as an increase in the sideways stance. Again, applying gas sorts it out. Feel past the limit is a bit odd. You get a real sense of the tyres stick-slipping as if they are letting go and re gripping as the load comes off. It is pretty easy to modulate this and control the slide. Wet traction out of corners is ahead of the capabilities of the SCIIs when they were new. What is particualrly striking is the way the front pulls deeper into the corners when the throttle is applied, this I assume being the result of the bigger front end slip angle.

In the intersts of science, I put the car through a local spot where water runs off across the road. It was enough to see the Contis, when worn down to 3mm, aquaplaning at 80 ish (KPH officer). Same stretch tonight was comfortable at a little under 100 (KPH officer). Obviously the tyres are new and the Contis used to go through it nicely when they were new also. It does confirm that aquaplaning wont be an issue unless you are taking the p, which given the large void ratio of the KU31 is no surprise. Steering feel lets you know you are in the standing water more directly and more obviously.

Emergency stopping showed no problems and again, a high level of grip and plenty of info about the surface and camber changes coming back through the wheel.

850 miles tyres settled down

OK, so with 850 miles on them, the Kumho KU31 seem to have settled down. Above comments about ride and compatability with the standard Fabia vRS springing and damping still apply. Road noise seems to be transmitted less harshly than with the Contis, but on really smooth surfaces where the contis would be very quiet, the Kumhos are a little noisier. Having said that, to qualify the difference, I reduced the "gala" setting on the radio from 3 to 2.

The handling is still under question. There is a lot of grip for sure, more than the Contis, but and it is a significant but, when I steer with these fitted, I find that a lot of lock is needed to get the turn required. The downside of this is that the difference in slip angle front to rear is quite large, making it very difficult to get all four tyres working at optimum. It would seem that there are two ways to overcome this. One is to throw the car at the corner, get the rear swinging and nail the throttle to hold it all at the required angle. However, this is not really a subtle approach and relies on pushing the car into oversteer by trail braking or brutal steering. The second method is to turn in at the same sort of speed as would have suited the Contis, but then nial the gas and keep the lock applied. Curiously, this creates a ensation not unlike driving a FWD car with an LSD. The car seems to pull into the apex and if you are unsubtle enough, this unsettles the back and then re settles it once slip angle is achieved. Not pretty, but very fast. While I reckon that with practice these will prove to be the faster tyre on any given twisty road, the Contis actually gave better handling. It would appear that some handling has been sacrificed to get more grip / speed which is not an unusual trade off.

Progression is now very good wet or dry. They dont warn as early as the Contis, but then they dont let go as early as the Contis either. They do let go in a manageable way and do communicate what is going on.

Conclusion:

I have compared the Kumho KU31 to the Continental Sport Contact SCII, a tyre that came second to the Goodyear Eagle F1 GSD3 in an Evo tyre test. The Kumhos cost a whole lot of cash less than the Contis (£40 less per corner at the best price I could get for Contis) but the performance is if anything more suited to the Fabia standard setup. Dry grip is higher than the Conti on even surfaces and better still once bumps are introduced. Wet grip is again higher and steering feel improved. The tyres are generally a little less progressive, but with higher overall grip levels. This is always a tradeoff. The higher slip angle required for quick cornering may be of concern to some, but get used to it and the confidence grows. The key thing is that the stiffer structure allows you to use more of the grip and feel more of what is going on. So generally, these tyres out perform the Continental SCII in grip and feedback levels, but are not as good in terms of progression and handling.

The Kumho KU31 compound is evidently a fair bit softer than the SCII and I think this is where the performance advantage has come from, so wear wise, they will probably not be anywhere near as good as the Contis, however, my SCII sidewalls went baggy long before the tread wore out anyway.

So they are probably not the best tyre in the world, but they are extremely good, suit the Fabia setup very well and regardless of price, a recommendable product. Many thanks to those that helped my with the choosing.

End of life update

So 25,000 miles under the wheels and the tyres are worn out. As they are directional, I have been unable to rotate them as I would for non directionals, so the front N/S is now around 0.75mm above the wear indicators. Rear O/S around 3mm tread left. To put this in context, the Conti SCII lasted 38,000 with rotation.

They have remained grippy to the last, still producing excellent dry grip and good wet when there is not standing water. Obviously, with standing water and only around 2 - 2.5mm of tread left (at the shallowest point) they are not performing as they did when new. The tyres have worn evenly across the tread and have not suffered from rounded off shoulders, which given the level of abuse thet the driver and the heavy PD lump subject them to is pretty remarkable.

The sidewalls have stayed firm and positive steering feel is very much present. I would say that in the dry, the tyres now take on a bit less of a sideways stance than when they were new.

Tyre noise has reduced a little from new.

The only slight downside is that over the last 5,000 miles or so, I have had a couple of occasions where the car has understeered in greasy damp conditions, then re gripped and thrown the back out. A return of the earlier observed stick / slip behaviour. To be fair I was taking the p completely each time it happend,by hoiking the car into the turn with a flick, and it was easy to catch.

So what to buy next? I have really liked these tyres and would be happy to have another set. However, I have previously driven a Fabia vRS with Toyo T1Rs on and it was so much quieter if my memory is not playing tricks. So I have a set of those on order for next week.

Chris

[ag.morley]

Nice write up Chris.....................BUT....still undecided...........Rainmasters???..so many tyres, opinions...........

[sharkrider]

mmm lets see what they're like in the rain... aren't the Kumho KU31 supposed to be one of the "budget" brands? (pray tell, how much?!) in the rain is where this may tell, due to less sophisticated compounds (silica mixes ect) .... not saying there will be a problem, I've heard other good reviews, but will be interesting to hear your report

[Mr Grumpy]

I was going to have PZ Neros on mine this week, but there aren't any in the country.
So I am putting 2 Kumhos on the front temporarily ( 215/40/16 ) and the two least worn Contis on the back until the Pirellis arrive.
The two least worn still have about 5mm on them so I should be ok for a bit.
£58 fitted and balanced.

[spinndrift]

I've got them on the fabia and the performance in the wet isn't quite up to the standard of P Zero Neros - otherwise they're a great tyre.

[Wayne Kerr]

Originally Posted by sharkrider

... aren't the Kumho KU31 supposed to be one of the "budget" brands?

Not any more buster, they've been snapped up by one of the big boys, Michelin IIRC.

[ag.morley]

Originally Posted by Mr Grumpy

I was going to have PZ Neros on mine this week, but there aren't any in the country.
So I am putting 2 Kumhos on the front temporarily ( 215/40/16 ) and the two least worn Contis on the back until the Pirellis arrive.
The two least worn still have about 5mm on them so I should be ok for a bit.
£58 fitted and balanced.

Mr Grumpy............Do you fit the 215/40/16 on the standard vRS 16" rims??. is there any benifit over the 205/45/16 ??......Thanks Andy...

[Mr Grumpy]

Originally Posted by ag.morley

Mr Grumpy............Do you fit the 215/40/16 on the standard vRS 16" rims??. is there any benifit over the 205/45/16 ??......Thanks Andy...

More tyre on the road ( although not a lot more ) = better grip, also they look a bit better, and in the case of the PZ Neros they are cheaper.

[Cheekymonkey]

I have 17" KU31s on my fabia and they are pretty good considering the price tag. As above, the wet weather performance isn't quite up there with the better tyres but dry grip is strong. They were certainly an improvment over the michelin pilot premacy tyres fitted as standard to my car!

[Tom_vRS]

Told you they were good!

I think the compare favourably with the Neros... well worth the cash imho.

[Tom_vRS]

£38.90 a corner for my Corsa... I know what will be going on when the Contis wear low...

[sharkrider]

Nice review Chris

[Chris GB]

Just updated the review of the KU31 now they are worn out. See post #1 above.

Chris

[Si Vxr]

hi mate wanted to say after reading your review and after haveing the same experance with the conti 2 as you on my VXR i thought i would try the kumho's and i have to say they are sweet loveing the grip compared to the conti's i to am doing a review on my forum vxronline.co.uk hope you dont mind me nicking your idea they will be getting well tested on the nurburgring next fri when i go over cheers again mate