if you're like me and brought a mountain bike and realised you going to be using it on the road a lot more than off road and realised how slow you are compared to other riders. Then this is you're cheapest most effective solution. change those slow high rolling resistance knobby tyres to slick low rolling resistance tyres. it makes a massive difference. you will accelerate faster and you will have a higher top speed and won't have to pedal as hard. not to mention puncture resistant, so all positives so far, but if you think buying these tyres will make you faster the riders on road bikes think again. they have bikes fit for purpose, this is just a temporary solution until you buy a road bike. but I have to say for the money spent it certainly has helped keep competitive and enjoy my rides alot more.