Hey guys,

I purchased a trek fx7.2 not too long ago and I love it, but recently I've been looking to go faster. I've always wanted a road bike but sadly I cant afford it, that's why I'm here, I'm looking to shed weight and try get a better performance from myself and my bike. Currently my average speed is 25 km h and max speed is 50 km h.

I've always heard that one of the best upgrades you can get for your bike is new tyres, is this true? Should I get new tyres?
I've only made minor changes to my bike, I changed the pedals for shimano pd-m540 and I've got the cleats to match, with a pair of mtb shoes that I got for 22 euro from Lidl. ( i cant afford decent shoes, id also like to stick with mtb shoes as they seem to protect the cleats more, I do enough walking in them to wear them down. I know i shouldn't..)

Is there anything I can do to make myself preform better and to reach new max speeds? I train daily on my cycle in and cycle home from work, my cycle in is a constant climb, I cycle as hard as i can for 30 seconds uphill then take a 10 second brake and so on. on the cycle home I just go full gas. This seems to be working as I can make my 9k cycle in 15mins, as opposed to 30 mins when I first started.

I'm not familiar with all the cycling lingo so if you could dumb it down for me that'd be great,
Thanks in advance for any help guys.