Plain guage vs butted tubing - cost vs benefits

[greyingbeard]

So, perusing on here I noticed that some expensive bikes are skimping on the frame using plain guage tubes.
Sulry lht rear traingle leaps out

Does this matter ?
Is the butting all about losing an ounce or does it improve the ride ?
ON a llight race bike - on a laden tourer ??

[irc]

The weight savings on small diameter rear triangle tubes will be miniscule. Possibly there is an advantage for a touring bike in having thicker tubes there as they are more resistant to abuse from baggage handlers etc? Less likely to dent?

For a tourer have the rear triangle the correct stiffness is IMO the important thing which Surly seem to have achieved as I can't fault the loaded handling in any way. Unloaded it is on the stiff side but I think loaded/unloaded handling is a trade off.

[reohn2]

The weight savings on small diameter rear triangle tubes will be miniscule. Possibly there is an advantage for a touring bike in having thicker tubes there as they are more resistant to abuse from baggage handlers etc? Less likely to dent?

Thinnner wall DB tubing on seatstays would be serious mistake in the rough and tumble world of touring,dent a seatstay and you've seriously compromised it's strength due to it being such a small diameter,it would more than likely take a kink,not good.
Ovalised chsinstays could suffer similarly IMHO

For a tourer have the rear triangle the correct stiffness is IMO the important thing which Surly seem to have achieved as I can't fault the loaded handling.....

Which proves the design is optimum for the job in hand.
Probably why it has such an enviable reputation as a bread and butter,tough as old boots,reliable touring bike

[robc02]

Many (most?) high quality tubesets only list the main tubes as double butted. Stays are typically tapered but retain the same wall thickness throughout (there are a few exceptions) due to the drawing process involved.

Details for Columbus Zona:
http://www.framebuilding.com/ZONA.htm

and for the Reynolds range:
http://www.equusbicycle.com/bike/reynolds/Reynolds-tubing-sizes.jpg

Surly LHT seat stays do not taper but the chainstays do, though not as much as on a lighter duty frame. Given the frame's purpose this seems reasonable as stated by R2 above. It is not clear whether the chainstays retain the same wall thickness throughout.

I know a lot of people say the LHT is a bit harsh / too stiff unloaded, but I find it fine. As an experiment I even tried mine out with some lightweight wheels and 23mm Michelin Pro Race tyres and still found it OK. - Maybe its a reflection on the type of bikes I normally ride or maybe I'm just plain insensitive

[531colin]

http://reynoldstechnology.biz/assets/pdf/rtl_2009_product_range.pdf
.....if you want all the numbers
robc02's link didn't work for me, but that could be me.....

[JamesE]

robc02's link didn't work for me, but that could be me.....

The website’s done something annoying to prevent people linking directly to that image. It’ll work fine if you copy and paste “http://www.equusbicycle.com/bike/reynolds/Reynolds-tubing-sizes.jpg” (minus quote marks) into a new browser window/tab.

[greyingbeard]

I shall let the designers carry on picking the tube for the job then

[greyingbeard]

So what are the advantages of butting ?

[robc02]

So what are the advantages of butting ?

It provides additional material at the joins where the stresses are highest, strengthening the heat affected zone without adding weight to the whole tube. Some info about the process here:
http://reynoldstechnology.biz/faqs/butted_tubing/1

http://sheldonbrown.com/cyclopedia/pages/p68%20butted%20tubing.html

[Brucey]

the other way of looking at it is that it saves weight/adds resilience for any given wall thickness at the joints.

Oddly enough butted main tubes make even more sense for welded frames than they do for lugged frames.

cheers

[CREPELLO]

Many (most?) high quality tubesets only list the main tubes as double butted. Stays are typically tapered but retain the same wall thickness throughout (there are a few exceptions) due to the drawing process involved.

That's not my understanding. The Reynolds tube list (using Colin's link) show's an extensive range of butted chain stays, with plain gauge in the minority. Maybe it's the seat stays you're referring to? I appreciate that butted chain stays are less of a priority on a tourer though. My Hewitt 725 Cheviot has 725 chainstays...and a descreet dint (from new, on the inside of the RH CS). Anyone care to guess whether it's plain or DB?

[PH]

My Hewitt 725 Cheviot has 725 chainstays...and a descreet dint (from new, on the inside of the RH CS). Anyone care to guess whether it's plain or DB?

Judging from the links above, isn't it most likely to be SB?

[greyingbeard]

flick the tube with fingernail along its length, if the note changes suddenly is butted

[PH]

flick the tube with fingernail along its length, if the note changes suddenly is butted

It's a pretty tapered tube so I don't think that would work.

[robc02]

The Reynolds tube list (using Colin's link) show's an extensive range of butted chain stays, with plain gauge in the minority. Maybe it's the seat stays you're referring to?

Yes, I looked mainly at seat stays. Of the chainstays I saw, Columbus Zona are plain but Life were butted. Also, the Reynolds chart in my link (which seems to work for me but not others) shows only one wall thickness for each chainstay type. I hadn't seen the page Colin linked to but, as you say, it does show quite a range of butted chainstays. I wonder if this is relatively recent? The chart I linked to is quite old, only showing tubesets up to 753.