KRhea

I'm looking at purchasing a new tandem (frame only) and am wondering how light a steel tandem frame can be built.
Any thoughts or ideas? I'm not interested in discussing carbon fiber, aluminum etc, just steel. Basically I wondering if I can build a sub 35lb steel bike. I have all the components ready to go but the frame is still a question.
Why steel, you might ask. I'm staring an incredible in the face and would like to take advantage of it if it makes sense. I purchased a custom road frame from a builder and we got to talking about tandems, my fit challenges, my love for all things steel etc and he mentioned, "how 'bout a great winter deal on a custom tandem frame" of course I had to ask how much and he said $1500, steel fillet brazed with any and all the bells and whistles we wanted including custom paint. Great deal in my opinion IF it can be exactly what I want and that's a sub 35lb bike.
I'm just curious if any board members are riding 35lb or less steel bikes or am I dreaming.

Thanks for any and all insight.

KRhea

TandemGeek

First off, you need to specify the configuration of the bike relative to weight. For example, most tandem builders use a medium size frame without water bottles, pedals, or any other attachments when they specify their "comparision weights". I don't know about anyone else, but we easily add 2-3lbs of "stuff" (frame pump, water bottle cages, spare tire, and saddle bag, never mind the weight of the computers) when between the time that a new tandem comes out of a box and hits the road. Never mind the 8lbs of water that gets strapped to the frame. Less I digress...

If you ride a medium or small size frame and are willing to spend a few bucks to get a few lightweight components, then a 35 lb steel tandem isn't all that hard to achieve. In fact, I think our '98 Erickson (4130 chromoly steel, not the new super-duper air hardened stuff) is about 35 lbs with the pedals and water bottles attached: I'll have to check. There are also several places where we could shave another pound off the Erickson if starting all over for almost no additional cost. For example, using Fusion rims instead of Deep-V would save about 100 grams on the wheels, another 100 grams could be shaved-off on on the seatposts using Thomson Masterpiece models, and easily 80 - 100 grams on my saddle which is about 325 grams (Selle Italia ProLink TransAm with all leather cover). You'll recall that while our tandem is small, it's also very long.

If you want to get really aggressive with gram shaving, you can save 1.5 lbs off of a conventional set of wheels by picking up a set 1,450 gram Topolino tandem wheels and, well, the list goes on. It's the little stuff that adds up.

KRhea

Thanks for the quick reply! I guess my question was not as succinct as it should of been. Let me rephrase it this way:
How light can a medium size steel tandem frame be built?

I have all the parts and they don't come much lighter without sacraficing durability. They include a full Campy Record kit with FSA Carbon cranks, custom built WhiteInd/Dt Swiss wheelset, Easton carbon bar/stem, Thomson Masterpiece posts etc etc. WTB Devo/Deva saddles etc etc.

I really want an idea as to frame weight which will then tell me finished bike weight with my components.

Thanks again for the quick response.

KRhea

Hobartlemagne 

I've heard of 35lb Ti tandems, based on that I would think a 35lb steel tandem may be a challenge.

antiquepedaler

Our Santana is listed as sub 35 lbs in the catalog and we wanted a light bike, but when you add necessities like pedals, saddles, a rear rack, bottle cages, etc., etc. our bike actually weighs 41 lbs going down the road.

TandemGeek

Not really....

How about 34.5 lbs with the "heavy wheels", pedals, and water bottle cages still on the frame, and 33.6 lbs with low-spoke count racing wheels? Yeah, it was lighter than I thought, but then again I don't think I ever bothered to strip it down and weigh it.

KRhea

TandemGeek, I'd really like to see a photo of that "lightweight" Erickson, sounds like that's about the weight I'm trying to hit.


KRhea

KRhea

Thanks a million!!!!!! Looks to me like a sub 35lb steel tandem will be no problem after seeing that slick Erickson.
I think we'll ditch the Avid disc on this bike and go back to a Record brake on the rear this time. That'll save a bit of weight right there. I'll have the builder include a disc mount for the "just in case". That's what we've used in the past and it worked perfectly for us in any and all conditions riding here in Oregon as well as northern Cal.

Thanks again, can't beat this place for great info.

KRhea

TandemGeek

It's not a no-brainer... Your builder needs to understand how to get the frame stiff enough without adding undue weight. Co-Motion and Santana do it with very specialized, zonally butted tubesets and builders like Erickson do it with ovalization, external butting, and some other tricks to give the frame the torsional strength it needs for stability and performance, while still allowing enough vertical compliance to make it comfortable enough to ride all day. I would think that your builder would need to be able to do all of this and bring the frame weight in for something around 8-9 lbs, excluding the eccentric to get you to your target weight without busting the budget on some really chi-chi, low gram components. A True Temper Alpha Q X2 carbon fork will take care of another 1 - 1.5 lbs vs. a steel fork.


The Avid caliper, rotor, and an adapter for the low-spoke count racing wheels is right at 506 grams, less ~170 grams when you remove the rear rim caliper and you're looking right at 3/4's of a pound net for that bad boy... maybe a little less if you use a disc hub.

zonatandem

It can, and has been done . . . many times.
Designed a custom tandem back in 1977 (yup, 30 years ago), small frame 21x19, super short wheelbase, single bike Reynolds 531 tubing and it weighed in then at 34 pounds.
Co-Motion lists their 2008 air hardened steel Supremo @ 30 lbs.total bike weight.
Yes, a c/f fork will work and make the steel ride even s-m-o-o-t-h-e-r!
Pedal on TWogether!
Rudy and Kay/zonatandem

KRhea

Zona, thanks for the info, I hadn't looked at the Supremo weight but you're right, it's listed at 30lbs. If that bike comes in at 30 then my sub 35 goal looks easily attainable. Looks like I'm headed for our first custom tandem, yippee i o.


KRhea

deanack

Who is the frame builder and do they want more orders??

t4mv

Yeah, what he said! ^^^^^

TandemGeek

Not to steal KRhea's thunder, but if you clicked on his profile and did a search of his more recent posts you'd probably find this one to be of interest: https://www.bikeforums.net/showpost.p...39&postcount=5

t4mv

Thanks, TG!

BloomingCyclist

Our medium - medium Santana Team Niobium (steel alloy from Columbus Tubing) with everything except filled bottles: pedals (Shimano mtn spd 959 not too light, seats (Terry Fly and Butterfly), rear wheel Phil Wood 40 hole Deep V rim, front Sweet 16, Winzip disk (large 10 inch rotor), stoker carbon tamer pivot plus (good but not light post with the spring and pivot mechanism), captain Thomson seatpost, Topeak Road Morph pump with guage, Flite Deck computer for captain, Cateye 300 with cadence for stoker, FSA cranks, carbon handlebar from Santana made by Carbon Concepts - weighs 38 pounds.

Bloomington Cyclist
Santana Team Niobium

KRhea

Builder is Paul Taylor out of Nevada who formerly built in the Bay area. You can see his work at BikeRX in Mill Valley. Great guy, easy to work with and his level of workmanship is great. Here's a shot of my new(8 months old) single bike from him:


Keep in mind the price I quoted in my first post [B]is not[B]his going rate for custom tandems. That's a "special buddy deal" for the numerous bikes I currently have him building/restoring etc.
I will say this, I've had numerous customs built over the years by a fair number of builders and Paul's service, quality of work and especially his pricesare some of the best I've encountered in over 30yrs of riding and buying road bikes. Paul specializes in singles and builds an average of 5 tandems a year.

As a side note, I contacted Co-Motion about the frame weight of their Speedster(8.5lbs) and Supremo(8lbs, listed at 30lbs in a med). So again my confidence is boosted when planning a 35 or even sub 35lb bike considering the components I plan to use.

KRhea
Portland, OR

TandemGeek

Actually, the Co-Motion Supremo can be used like a parts catalog or how-to-guide for shaving nearly 5 - 7 lbs off the average tandem...

For those who don't know, the Supremo (30.0 lbs) and Speedster (35.5 lbs) use the same Reynolds 631 air hardened steel frameset where the only discernible difference is canti-bosses on the Speedster which are absent on the Supremo as it is spec'd with front & rear caliper brakes. I'm not sure where the extra .5 lbs is coming from on the Speedster weight quoted by Co-Motion unless that was referring to the Reynolds 725 framesets used on the Primera and as the core for the Speedster and Supremo Co-Pilots.

Regardless, the point is that the majority of the weight savings is coming from the components -- primarily the wheelset and fork as the biggest contributors. The cost per gram is actually pretty decent at around .89 / gram, but all of those other little grams that come off in the various other components selected for the Supremo do add up. Therefore, you're looking at a 33% premium for that lighter weight tandem. Upgrading from the Primera to the Speedster is proportional: about a 25% premium. The same cost premium is what you'd pay for upgrading + the original cost of the components that came with your tandem and that you replaced for an existing tandem, ala the Harley Davidson aftermarket bonanza.



A dirty little secret for weight weenies: Check out the weights of FSA's alloy Gossamer cranks vs. the carbon SL-K models before assuming that the carbon is lighter.

zonatandem

Moral:
The more you pay, the less you get . . . (in weight)!

Will the Taylor tandem have lugs? Have owned 2 beautifully lugged steel tandems and now own a lugged (with window cutouts) custom carbon fiber 2-seater.
Close-up of lugged rear BB on our Zona tandem.
Pedal on TWOgether!
Rudy and Kay/zonatandem

KRhea

That is some mighty pretty BB work on that carbon monster sir! The Taylor will be fillet brazed.


KRhea

zonatandem

Have owned a fillet brazed Tange Prestige custom Co-Motion . . . one tube just melted into the next. Put 57,000 miles on that one.