It has begun.


Tandem parts purchased!

FSA SL-K tandem rear crank
Disc road fork
Avid BB7 road discs
Shimano 11-28 cassette


I need to order the wheels and frame tubes next... which will require some more work to build up the funds to order that stuff. I would have ordered the tubes first, but I did it this way so I can have everything I need on hand to build the rolling bits of the bike to be able to measure and fit them up. I expect I would have gotten excited and tried to build it off of measurements and it likely wouldn't work once everything came in.


I will start a build thread for it at some point...

 

I raced tandems for a few years. My suggestion on a build would be: as stiff and as strong as you can. We broke rear spokes/ wheels and chains (both of them) very frequently. Use heavy duty or tandem specific parts as opposed to road parts.

 

Good suggestion.


There aren't many tandem specific parts that you really need... wheels/rims being one of the ones that does need to be heavy duty.


Im going 88mm deep, 23mm wide carbon clincher with disc brakes for our tandem. We wont be racing, but I want aero. I will also be getting them built with 32 spokes front and rear to give some extra structure.
135mm rear spacing and 100mm front. I wont be getting the 145mm special tandem hubs. I feel like they wouldn't really be needed at my team weight and our use (recreational riding)


We live in an area without hills and knowing my wife, we wont be riding up any mountains on the tandem. I have 140mm road discs for this build.


Im using the new standard for forks (1 1/8" to 1 1/2" tapered steerer tube) so there will be added structure to keep it all in check. Im going to be using a nukeproof headset for 44mm head tubes that has provision for the tapered steerer tube.


Full Buildout plan:

My custom 7005 Aluminum frame
Carbon tapered disc fork
nukeproof warhead 44IETS headset
Easton type front eccentric bb shell
40tooth front crankset (I want to find an FSA SLK to match the rear, if I can. If not, I may end up with a gossamer or an ultegra front crankset)
FSA SLK rear crankset (30, 39, 52 tooth)
Shimano 5700 rear derailleur
Shimano 5703 front derailleur
Carbon 31.6 seatposts
Aluminum captains handlebar (TBD)
Ebay Carbon bullhorn aerobar for stoker
Shimano 5700 cassette
Avid BB7 road discs
Kalloy Uno 9 front stem
Custom fixed stoker stem
Continental GP4000s2 28c tires
CarbonSpeedCycle 88mm carbon rim, 23mm wide, 32 spoke
Shimano 5703 STI levers

Then random add ons like pedals, chains and cables that will finish the bike...



Done up a spreadsheet with prices, parts and weights and, depending what the frame weighs, it will be about 13kg (28.5lbs) That's with a 3,000g frame (6.5lbs)

 

Looks good. If you can, get a strong chain between the two cranks: maybe a track chain?

 

 

I would not recommend going weight weenie on a tandem build. It is no fun to be swaying side to side and worrying about breaking your carbon clinchers over every pothole. The stoker can't see what is coming and sit directly over the rear wheel, and the result is a lot of force on the rear wheel.

For reference, this thing is just under 28lbs

Don't re-invent the wheel. Use tandem hubs/spacing, use a tandem fork, get a rear suspension seat post, etc. A lot goes into making a tandem that is fun and reliable.

Also, make sure your frame is very straight, the alignment from front to back can be a big issue.

The best upgrade i can recommend is a belt timing chain. It takes 2 chains to replace the timing chain so the cost adds up pretty quickly.

You can do it!

 

88mm carbon clincher are pretty friggen stiff, but yeah, if there is a stronger option, I would do that.

 

My thought is 36 or 40 spokes, at least in the rear. What's the weight of 16 spokes for a much stronger wheelset? On disk hubs, the flange position is not a lot different between mountain 135's and tandem 145's. For White Industries:,

Tandem: 30mm Center to Left and 23.5mm Center to Right
Mountain: 35mm Center to Left and 21.0mm Center to Right.

Not a lot of difference on the right side from the standpoint of latteral strength, but the spoke tensions will have much more difference L vs R on the Mountain hub than on the Tandem hub.

Again, from White Industries, only $20 difference in price between those rear hubs. I don't know about other brands, and, WI is generally pricey.

If the price difference is the same on other brands, go with the tandem, and don't feel obligated to use the same spoke count Front and Rear, but you knew that.

 

 

The goal with tandem spacing is twofold. Lower spoke tension and wider/larger bearings. The tandem is hanging off the rim and the more spokes the lower the stress on the rim at the nipple.

 

 

Thanks, Im not doing it weight weenie wise in reality. I just want to build it so that its not 100lbs. Im doing that in components mostly compared to what some tandems run (steel handlebars, posts, cranks, etc). The weight estimates are just that... I want first and foremost a rideable bike that wont have issues.

The 88mm Carbon clincher with 32 spoke will be MORE than stiff enough. The carbon wheels are way more stiff laterally compared to aluminum wheels of the same size and shape. Once strung with 32 (very short) spokes the spoke angles with the very deep profile will be greater than that of people running aluminum lower profile wheels with longer spokes (keeping the wheel stronger) Main reason for that choice is I have wanted carbon wheels for a long time and the deep profile should help a little bit being the speeds tandems can easily carry.

The hub spacing at 135mm with MTB hubs will be more than enough, coupled with the short spokes and deep wheels as mentioned above.


I will be building a frame building jig to hold it all square relative to each other.

 

OK Well thought out.

I used the same logic for my commuter with build in mind for loaded touring. Normally would be 40 spokes, 700C, but I went with 36 spokes on 26" mountain rims.

You have convinced me.

 

I tend to over-think things. The engineer in me thinks of things too much to be honest.

You should see the CAD file I have for this thing. Broken down into isometric views of most connection points now that I have the fork and a few other components picked out.



Fork was the biggest part of finishing my design though. the rest of it will be a set the jig and make it fit type thing.

 

Please tell me the fork will not be Al.

Edit: OK I see it now as a purchased item.

 

Full Carbon, disc specific.

I will have the fork in a week or 2.

I can order my tubing in a few weeks....

 

Went to do some of Colorado's classic rides with my Dad this week since we are both unemployed at the moment (he's retired) and I've never done any of them...
Rode Dr. Park and 401 in Crested Butte and Monarch Crest out of Poncha Springs.


The views on 401 trail were ridiculous

New bike getting broken in:






Old man getting after it:


Glory achieved:

 

First tandem part came in. It's glorious.

 

Build Thread time

 

Is this still happening on sat? Planning on bringing bib shorts and all to MRLS