Sumitomo BC100

Picked up these tires fitted to wheels second hand 205/40R17 direct replacement for my 195/50R16 set up on my Fiat 500 twin air S
Initially they felt good a little more of a harder ride and direction change improved, however when pushing hard into corners they understeer and when lifting to correct they transition to lift off over steer, very unpredictable and as such I'm looking to replace them as they wear out however they have only covered a few miles and based upon the hardness of the compound I think this is going to be quite a while, I'm not sure it they will improve as things go but give me way less confidence in the car when pressing on way worse than the 16" set up maybe the car is now over tired and might need to drop the width to 195/45R17 for the next set otherwise I'm looking to fit semi slick track tires as dry cornering is a priority for me I'm not really interested in high mileage but do need to bring back cornering confidence which was this cars forte

Hello, I have done quite a few reviews on tires here but with other cars and tires under Astraman. I have another Astra a1.6 j series bought it last year after the other one decided sodd this world I'm done here, so bought this one and its great, car came a from Vauxhall dealer came with brand new tires on front and back.. the rears have the BC100 on, ah..I thought these again my experience with these was on my Vectra 1.8 which were then under Falken owned by this lot and were then ZIEX ZE912 pattern which are the BC100's. The grip then and now I will only talk about wet grip and wear as dry grip as with most tires can be very close unless your on the really cheapo's plastic rubber tires. On the front of my Vectra they only did 7k but didn't fail me in the wet at all but the wear was really poor, so seeing this tire again on the rears of my latest car didn't please me too much but here they are lets go.

Well they are very good in the wet and well planted on the road a tad hard and they are quite stiff in the walls, but being on the rear where the cars grip is they have been very good in all weathers, they haven't been too bad on the wear they have done very close to 19k and are now at 5.6mm on both rear tires as they are not much over 7mm new so not too shabby, I run my tires 4psi above comfort as one psi below base pressures is under pressure.

Will I buy them again for the rears yes I will they do the job ( on my car ) please remember not we all don't drive the same and differ with our tire pressures and weight of cars but they do for me and they are still not too expensive as lately near me the prices have gone stupid.
I hope this helps some of you I dont drive like a spanner any more but just now and again I do flick into chase mode.
Cheers

First of all I'd like to clarify that I bought the car in late february 2023 with these tires (DOT 0119) fitted on by the previous owner sometime during 2019. Between the tires being fitted and me buying the car, it was not used very much. In fact it was sitting for most of that time with occasional use to keep the battery "healthy". I've driven about 4000km on them and I think it's fair to say I am not very impressed.

The first problem I encountered was the fact that while they aren't dry rotted, microcracks have started forming inside the grooves in the tread and on the sidewall to a lesser extent, but since they had still plenty of tread left I thought to give them a go for a while before changing.

On average-high quality dry pavement the grip is not phenomenal but I wouldn't consider them dangerous to drive on. They can spin for a few meters when launching in first gear and momentarily when changing to second quickly near the redline. Totally expected for an old rwd car with about 140 horsepower more or less. When starting uphill on poorer quality pavement the wheelspin is unavoidable no matter how smoothly I try to take off. In the wet on the other hand it takes almost zero effort to spin at low speeds and it's not hard at all to induce oversteer when cornering at a slow pace.

I haven't found the limit of grip to be progressive, as when inducing oversteer on purpose and the "drifting angle" becomes a bit higher there is a tendency to fishtail.

When driving on a twisty road, the front tires are slow responding, meaning there's lag between turning the wheel and the car changing direction. I know the 65 series profile is big but I'm not too keen on that behavior.

The worst part is braking, as I've had to "panic" brake on two seperate occasions (average pavement, dry weather, tires were not cold) from moderate speed in order to avoid obstacles and the tires didn't brake efficiently enough. The front wheels locked up much more quickly than anticipated (car has no ABS), meaning the brakes outpowered the tires by a lot. I'd expect better performance and having to pump the brake pedal less to keep control of the situation. Thankfully none of the afformentioned situations resulted in an accident.

To summarize I wouln't buy these tires again and I wouldn't reccomend buying them to anyone since they somewhat disappointed me. Sure, I didn't buy them new and they weren't stored in the best conditions when I got my car and started driving it but I surely expected better braking and handling to some extent.