Sow's ear into silk purse?

[supersadie]

Hi
As a beginner I thought I'd get a dirt cheap bike to go up and down the road on...and then maybe a little further afield. Max I've ever done was 10 miles at Easter, having cycled about twice in the last twenty years!
Bought a second hand ATB (basically a road bike with MTB tyres). It was a cheap brand to start with but It's hardly been ridden.
Trouble is, it's darned uncomfortable to ride. Ok it has no suspension and a hard saddle (I'm a girl without much 'natural padding'!) but even so, it seems to take a lot of push to make it go. My 13 year old rode it to town and said when he stops pedalling it stops moving after about 2 seconds whereas his mtb freewheels for a good deal longer. There's nothing obvious impeding it, like brake calipers or a dead bird in the spokes...
Can anyone tell me if there's a good way to improve its performance? I don't want miracles but if I can tweak it with a spanner that would be brill!
It has no suspension, 18 gears and the saddle is below handle bar level. I am 9st, 5ft6in with 30in legs. Telling you this in case it's something to do with geometry!
Many thanks

 

[gbb]

If the brakes are'nt rubbing sadie, it only really leaves the wheels themselves.
Trouble is, cheap bikes sometimes have really nasty cheap wheels, and the hubs probably want adjusting...and unless you're proficient in things mechanical, its a job for a LBS.

Just re-read your post...missed the bit about the seat below the handlebars. Sounds wrong. Either the bars are too high, or more likely your seats too low. Ideally you want to be able to have one foot on the pedal while your bums on the seat and your leg should be nearly straight.
If your legs dont extend, you get a terrible burning in your thighs.

Doesnt make any difference to the ability to freewheel...its a comfort thing.

 

[montage]

Something is rubbing somewhere....My guess is the wheels aswell - LBS job unless you are able to sort it out

 

[gbb]

Forgot the obvious sadie...make sure the tyres are as hard as possible. Soft tyres are like riding in treacle.

 

[nuovo_record]

hub bearings are probably too tight - quite an easy fix.....