Sizing a frame

[talisman50082]

I used to ride an mtb with a 20" seat tube,the top tube felt to long. Have an old trek 4100 which is 19.5 and its to short. Have a 20" hybrid which feels to short. Just sold [ i hope] a 23" road bike which feels just to long. Seems to me a risk to buy any bike without sitting on it first. I think the seat tube length only helps with stand over? The stand over on a 22" may be close but would it be to long [sale on ebay].

 

[LSAF2011]

I came across this the other day, hope it helps a little.

http://www.cyclescheme.co.uk/community/how-to/how-to-understand-bike-geometry

 

[talisman50082]

Thanks ,very helpful.