Increasing the size of tyres on a hybrid We are planning on doing some mountain biking in a few weeks time and we'd like to get some wider tyres for my wife's hybrid. I know there are similar questions and answers out there on this topic, but I need some specific help to make sure I buy the right tyres.

The bike is a Ladies Scott Sportster 50 2015, the best website I could find with a fairly accurate spec is here



It's currently got Kenda K-180 700 x 38c / 30TPI tyres on it, which are fairly good all rounders and capable of running on clean forest paths but I don't think they would handle anything heavier.

It's got disk brakes so there isn't a clearance issue there, but I have noticed the frame is generally narrower than true MTBs, here are some photos i took of it.



Has anyone put larger, knobblier tyres on this kind of hybrid? whats the largest I can get away with? - I'm also slightly confused by all the tyre sizing, I'm sure someone told me this is a 27.5" tyre, but 700 seems to mean 29" on a lot of websites.

Any advice is very much appreciated, Thanks.
For a 700c tyre you would be replacing it with a 29" MTB tyre.
The best way for you to determine what size tyre you can get to fit is to simply measure the gap between chain and seat stays as these are the most likely areas to cause problems with clearance.

Providing you don't want to ride anything too gnarly (i should hope not on a hybrid), a 700x35C cyclocross tyre could give you a much more grippy/knobby option without needing more clearance.  Something like this maybe?