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lightest steel tubing? (calling on steel experts)(8 posts)

lightest steel tubing? (calling on steel experts)DougSloan
Nov 3, 2003 9:06 AM
What's the lightest steel tubing now? I'm thinking of a custom fixed gear, but want the weight as low as possible, and the event rules may require steel conventional frame design.

I want a light bike, but with a bit longer wheelbase and not as steep as a track bike. The bb will need to be very stiff to handle 25 rpm mashing up steep hills. Essentially, wanting a light steel road racing frame with long rear opening drop-outs (even if it's the wrong term).

Also, is all modern tubing designed for welding, not lugs? Is a welded bike lighter? Do you sacrafice strength, durability, or stiffness with welded steel vs. lugs?

Thanks.

Doug
re: lightest steel tubing? (calling on steel experts)Rusty Coggs
Nov 3, 2003 9:37 AM
The light stuff is Ultra foco,EOM 16.5 and the new True Temper S3. Actual frame weight is going to depend on diameter and butting,which is influenced by frame size, and rider strength and weight,and desire for stiffness..The new air hardening stuff is designed not to loose strenth when welded,but can also be lugged. Tig is lighter,everything else being equal, and does not give up durability if done right. Durability can be sacrificed for lightness, in either construction. You can get adequate stiffness in either,but TIG allows more latitude for oversize tubing and shaping.
re: lightest steel tubing? (calling on steel experts)BenLomond
Nov 3, 2003 10:10 AM
Doug I'm not an expert, but I believe the lightest steel bicycle tubing would have to be the tru-temper s3 or reynolds 853 pro. I believe framesets of 3lbs or less are possible with the s3.

Welded will be slightly lighter, but not as strong or durable. Most of the really light steel have shaped tubes which lugs are not available for.

Track dropouts are what you are talking about.

For more info from better informed people you might try asking on the framebuilderslist at phred.org.

cheers,
Clyde
re: lightest steel tubing? (calling on steel experts)flyweight
Nov 3, 2003 4:34 PM
S3 is probably what you're after. Check out the Waterford R-33. All R-33's are custom built so they could easily build one up for you with horizontal drops and enough strength to withstand a fixed gear.

Generally speaking TIG welding will be lighter than lugged construction though that's certainly not always the case if you use well sculpted lugs and silver brazing (silver melts at a lower temp thus allowing thinner tubing than TIG welding) I've seen plenty of lugged Waterford frames that weighed less than TIG welded Reynolds 853 frames.

Lugged and TIG welding are nothing more than two approaches to the same problem: having enough metal at the joints to withstand the heat of welding/brazing. With TIG welding all the extra metal is on the inside in the form of butting. With lugs it's mostly on the outside as a lug.

There is no sacrifice one way or the other in terms of durability or stiffness when going with lug or TIG welding.

Probably the lightest way to build a frame would be fillet brazing with silver. Very few people are skilled enough to do this. Jeff Lyon is probably the best.
Actually...Nessism
Nov 3, 2003 11:12 PM
silver should not be used for fillet brazing because micro cracks form when the molten metal solidifies. Some people do try to use silver to build fillets, but the welding engineers generally frown on it. I'm not an expert on such matters but the framebuilders forum had a long thread on this subject not too long ago and this was the long and short of it.

As far as TIG requiring thicker tubing, S3 and Ultra-Foco are designed to be TIG welded and both are the thinnest tubing on the market.

Regarding which tubeset to use, my vote goes out to either S3 or Dedacciai EOM16.5. Both of these tube sets use shaped tubes which ovalize the down tube in the lateral direction at the bottom bracket. This is the shape to have to stiffen the bottom bracket area of the frame. Tall "Mega tube" shapes are ovalized vertically which is the wrong direction to resist bottom bracket sway.

Ed
Actually...flyweight
Nov 4, 2003 8:52 AM
I know it's frowned upon but I've seen plenty of frames that have several thousand miles on them built this way. Not too many people I'd trust to do this.
re: lightest steel tubing? (calling on steel experts)Birddog
Nov 4, 2003 6:40 AM
Check out this guys work and give him a call. He's getting good revues
http://www.kirkframeworks.com/Photo%20Gallery%20complete.htm.
Birddog
thanks, everyoneDougSloan
Nov 4, 2003 7:44 AM
Hey, good info. Unless he says he can't do it, I'll probably have a local builder I know do it. He mostly uses aluminum now, but used to do lots of steel. His brand is "Flow". If I'm not satisfied that he'll do what I want, I'll take a look at some of the other builders mentioned. Thanks.

Doug