Double butted frame

[ManBearPig]

Ciao.
I have been looking at road bikes and most of them (unlike my Giordano) have double butted frame. Can anyone explain what are the advantages or characteristics of such bicycle frame? Like an elderly would explain it to a child

[Painkiller]

the most simple way to explain butted tubes is this the tubing walls are thicker where needed for strength (i.e, joints). and thinner else where as in the middle of the tube. double-butted is as it implies,meaning two inner tube wall thicknesses and so on for triple and even quad butted tube sets. mostly seen in steel framed bicycles.

[ManBearPig]

(09-26-2019, 09:18 PM)Painkiller Wrote:  the most simple way to explain butted tubes is this the tubing walls are thicker where needed for strength (i.e, joints). and thinner else where as in the middle of the tube. double-butted is as it implies,meaning two inner tube wall thicknesses and so on for triple and even quad butted tube sets. mostly seen in steel framed bicycles.

how does it typically affect the weight?

[Painkiller]

Typically with a quality tube set butted style tubes would be lighter. some as much as 30% over straight gauge. You have to have the thickest part of the tube @ the joints . this is where the frame is stressed the most. So if your tube is .075 thousandths and straight gauge. it runs the whole length of the tube. Where as the butted tube @ .075 can be only .035 thousandths for 90% of its length which is where the weight savings come in to play. The thickest part of the tube is only and inch or so to the joints. The variables would be how the tubes are attached to each other that also plays a role in overall weight, i.e. lugged, fillet,welded, bonded. and lastly how the tubes are designed for certain ride characteristics the manufacturer is trying to achieve.

[ManBearPig]

(09-29-2019, 04:45 PM)Painkiller Wrote:  Typically with a quality tube set butted style tubes would be lighter. some as much as 30% over straight gauge. You have to have the thickest part of the tube @ the joints . this is where the frame is stressed the most. So if your tube is .075 thousandths and straight gauge. it runs the whole length of the tube. Where as the butted tube @ .075 can be only .035 thousandths for 90% of its length which is where the weight savings come in to play. The thickest part of the tube is only and inch or so to the joints. The variables would be how the tubes are attached to each other that also plays a role in overall weight, i.e. lugged, fillet,welded, bonded. and lastly how the tubes are designed for certain ride characteristics the manufacturer is trying to achieve.

Ouh, serious explanation Much appreciated, I believe that I understood the general idea.
Btw, what is your favorite bike frame material?

[Painkiller]

you probably guessed, Steel of course, however I have vintage bonded lugged alloy and carbon fiber road and Mtb that are very dear to me too.

[ManBearPig]

(10-02-2019, 08:18 PM)Painkiller Wrote:  you probably guessed, Steel of course, however I have vintage bonded lugged alloy and carbon fiber road and Mtb that are very dear to me too.

hahh, I guessed it right, yes I've been biking only on alloy frames as far as I remember so there are no grounds for comparisons. There are some post-war steel bike (great-grandfather's) memories from when I tried to balance on adults bicycle while being 5-7 yo Still have scars on my thighs.