frames . stiff and flex ?

stronginthesun

ive had cheap mt bikes a dawes giro 300 and now a trek 4.5 . i keep reading about how stiff frames are and no flex ? on all the bikes ive had the frames have never flexed and all feel stiff ! explain ? or is it just marketing nonsense ?

danowat

I think I am just not sensitive, I have a number of bikes, and I can't detect a difference in stiffness or flexing in any of them either.

nakita222

They are laterally stiff but vertically complaint.

P_Tucker

Marketing nonsense. Very astute.

nmcgann

nakita222 wrote:

They are laterally stiff but vertically complaint.

Like what you did there

nmcgann

danowat wrote:

I think I am just not sensitive, I have a number of bikes, and I can't detect a difference in stiffness or flexing in any of them either.

I could make the chain rub the front mech cage on my old ally/carbon summer bike frame when really applying max torque, so there was flex there. It made no difference to the performance of the bike though.

centimani

nmcgann wrote:

danowat wrote:

I think I am just not sensitive, I have a number of bikes, and I can't detect a difference in stiffness or flexing in any of them either.

I could make the chain rub the front mech cage on my old ally/carbon summer bike frame when really applying max torque, so there was flex there. It made no difference to the performance of the bike though.

I could do the same on my old Bianchi....but the weld broke where the downtube met the BB after 2 years, so that flex may have eventually had a bad impact. I cant say the flex was responsible for the crack, but...

here's the piccy...

Berk Bonebonce

Stress corrosion at the weld join.

Even the budget bikes are stiff these days.

cyberknight

I have ridden titanium ,gas pipe steel and aluminium and you can definitely tell the difference .
The steel was heavy, the aluminium is light but you can feel the buzz and titanium ahh the most comfortable thing i have ridden and if i win the lottery i know what bike i shall be getting .
Carbon? it might be the way things are but i like the look of a "real" bike

Evil Laugh

I can feel fairly vast differences between my bikes. Guess it also depends on how heavy you are and what sort of force you apply to the pedals.

I'd imagine the difference between top end stuff gets exaggerated but while stiffness may get overstated it is def not just marketing nonsense. Try a pair of r-sys for example and then say it's all rubbish. Or head downhill at speed with a wobbly fork.

If I get out of the saddle on my steel bike I can look down and see myself pushing the bb from side to side.

MarcBC

30 years ago when I was a track rider, I could tell the difference quite easily on some of the track bikes. The rear triangle flex was sometimes hideous when sprinting.

Perhaps some road bikes have these differences?

Richa1181

It all depends on how you ride. If you're just commuting I doubt you'd notice much but if you start climbing or sprinting you'll certainly see the difference between bikes. unless they're all awesome bikes anyway

I had an aluminium bike and I thought it was great, it was only when I swapped to carbon I realised what stiff actually meant!

nferrar

It's weird, although I could can see the rear end flexing on my Spesh Roubaix (only under heavy load) I could never detect bottom bracket area flex and when climbing out of the saddle for example everything felt solid. However I had a test ride on a Look 586 recently and it felt really weird, I was much more aware of the bike beneath me and how solid it felt when out of the saddle.