General frame geometry question....

sopworth

I have had a search on the forum but can't find the answers I'm after.

Basically, could someone please explain to me what separates a frame from an aggressive type racing frame to a sportive type frame etc? What gives a frame/bike a relaxed geometry to make it suitable for riding all day? Is it all about reach?

Secondly, what happens when you buy a bike that is too big or too small? I hopped on a 54 Felt F4 yesterday after the guy in the store said that would be my size in a Felt - i'm 6ft. He told me that he used a 54 felt and he was the same height as me. The bike felt low but the reach was absolutely fine. Maybe my lack of bike knowledge gave me the wrong signals!

Would be really grateful if one of you knowledgable guys and girls could throw some light onto the subject.

Kind regards,
Mark.

Monty Dog

Generally, sportive frames have slightly slacker frame angles, longer headtubes and shorter toptubes in comparison to a more race-oriented bike. Regardless, get yourself a bike fit as that also includes things like you flexibility and proportions. FWIW generally, a 6ft rider would typically ride a 56 or 58cm frame - but different makes measure their frames differently.

sopworth

Monty
Thanks for your reply.
It's a confusing area for someone not in the know - which I most certainly aren't but am keen to learn.
Will look into the bike fitting process
Thanks
mark

Burghley

Hi Mark

Monty Dog has given you a very good initial resume of frame geometry.

Nearly every bike is a compromise in some respect, as manufacturers try to create a multi-purpose frame to cater for a variety of needs.

Before parting with a lot of money for a shiny new bike, you need to have some idea what you want it to do. For example, is it to be used for commuting; for touring with luggage; for recreational use at weekends; for audaxes and sportives; or for racing. Answering these questions will help to define the sort of bike that might best meet your needs.

If you can, visit a few bike shops, and try out a number of bikes. You will be surprised how different each feels. Ask staff about the best size frame to go for, based on your body type (two people of identical height may have a 12/15cm difference in leg length and/or arm length - which might correspond to radically different frames and set up).

Although a 54cm frame seems quite small for your height, it may be correct. My hunch is that a 57/58cm frame may be better, however.

Rgds

Pete

MrIP

Hi Mark,

If it helps I am 188 cm (6'2" +) and I ride a Felt AR (same geometry) in a 58cm with a 10cm stem. It is a purfect fit for me.

Regards

Mrip