Tandem Cycling - Aero up front-how deep?

I've seen some threads about using a HED3 up front on a tandem. It looks okay from what I gather. But, may ride a little too harsh for longer rides. Also, I would be a bit leery about jamming it through a high speed turn on a tandem.

I am planning on building up a set of aero wheels for our new tandem. I was wondering if anybody out there is using deep carbon on the front, and how deep can you go with a tandem? I'm leaning towards a Stinger 9 for the rear. Can I safely go with a stinger 6 or 7 on the front?

BTW- I will have a disc brake option on the rear hub for the hills. Don't want to melt the wheels.

Thanks for any input.

RP

If you go with too deep a dish you have to worry about the spoke angle on a wider hub. What width hub do you have on your tandem? That (of course) is mostly an issue with the rear wheel. An engineer at Zipp told me that the optimum combination for strength and aero for my Calfee would be a 505 or 404 rim. I believe merlinextraligh (http://www.bikeforums.net/member.php?38651-merlinextraligh) uses a Zipp 1080 rim. I'm sure he'll pop in and give his review of them. You might want to look at Edge wheels too. Ritterview has had some luck with them.

If you go with too deep a dish you have to worry about the spoke angle on a wider hub. What width hub do you have on your tandem? That (of course) is mostly an issue with the rear wheel. An engineer at Zipp told me that the optimum combination for strength and aero for my Calfee would be a 505 or 404 rim. I believe merlinextraligh (http://www.bikeforums.net/member.php?38651-merlinextraligh) uses a Zipp 1080 rim. I'm sure he'll pop in and give his review of them. You might want to look at Edge wheels too. Ritterview has had some luck with them.

Good point about rear hub width. Our tandem is being built with 130mm rear wheel spacing. So, this may be good for a deep wheel.

RP

BTW- I will have a disc brake option on the rear hub for the hills.

Our tandem is being built with 130mm rear wheel spacing.

What 130 mm disc rear hub are you planning to use? Velocity? (http://www.velocityusa.com/default.asp?contentID=570) The choices are slim.

What 130 mm disc rear hub are you planning to use? Velocity? (http://www.velocityusa.com/default.asp?contentID=570) The choices are slim.

Both Chris King and Phil Wood offer a tandem specific hub with a 130mm option. Also, I hear that a DT Swiss MTB hub can be used by just changing the spacers on the hub. I have not been able to confirm this yet.

Right now, I'm leaning toward the Chris King, for weight, and price.

Rick

If you go with too deep a dish you have to worry about the spoke angle on a wider hub. What width hub do you have on your tandem? That (of course) is mostly an issue with the rear wheel. An engineer at Zipp told me that the optimum combination for strength and aero for my Calfee would be a 505 or 404 rim. I believe merlinextraligh (http://www.bikeforums.net/member.php?38651-merlinextraligh) uses a Zipp 1080 rim. I'm sure he'll pop in and give his review of them. You might want to look at Edge wheels too. Ritterview has had some luck with them.

Homey, what width hub are you running on your Calfee?

If you go with too deep a dish you have to worry about the spoke angle on a wider hub. What width hub do you have on your tandem? That (of course) is mostly an issue with the rear wheel. An engineer at Zipp told me that the optimum combination for strength and aero for my Calfee would be a 505 or 404 rim. I believe merlinextraligh (http://www.bikeforums.net/member.php?38651-merlinextraligh) uses a Zipp 1080 rim. I'm sure he'll pop in and give his review of them. You might want to look at Edge wheels too. Ritterview has had some luck with them.


Good point about rear hub width. Our tandem is being built with 130mm rear wheel spacing. So, this may be good for a deep wheel.

RP

Our wheels are 520 rims (the Zipp 808 rim) on 145mm spacing.

Zipp doesn't warrant them, and doesn't recommend this usage due to the spoke angle.

We've broken a couple of spokes in a few thousand miles of riding. Other than that they've worked fine.

the good news is that the rim is sufficiently sturdy that the wheel was still relatively true and rideable 2 spokes down.

Since we've replaced the 2 spokes we haven't had further problems, but we're not using the wheels on an every day basis anymore.

We've also time trialed with a HED3 front. It worked fine, but I wouldn't want to ride that wheel on a regular basis, given the ride feel.

On a tangent, where are you planning on doing most of your riding? There's nothing anywhere in Florida that needs a disc brake.

Northern Georgia is manageable without a disc brake.

If you're going to be doing a steady diet on long twisty descents, I can see the case for the disc, but if most of your riding is around here, I would skip the disc.

My take on disc brakes FWIW

http://everestchallengex2.blogspot.com/2008_09_01_archive.html

On a tangent, where are you planning on doing most of your riding? There's nothing anywhere in Florida that needs a disc brake.

Northern Georgia is manageable without a disc brake.

If you're going to be doing a steady diet on long twisty descents, I can see the case for the disc, but if most of your riding is around here, I would skip the disc.

My take on disc brakes FWIW

http://everestchallengex2.blogspot.com/2008_09_01_archive.html

Most of our tandem riding will be in your back yard my friend. You know who we are :-)

The rear disc will only be on the bike when we do travel to the hills. The rims brakes will always be on the bike. I want the rear disc because we will have some carbon rims when we do the hilly events. I don't want to overheat the carbon rims. And, if it happens to rain, the disc will help out.

"How" you say, will I operate three brakes at one time? The rear disc will be a hydraulic brake operated by my very capable stoker wife. Think of it as a modern "drag brake".

Hope you had a race this weekend merlinextraligh (http://www.bikeforums.net/member.php?38651-merlinextraligh)

Rick

^ Sounds like a reasonable plan. We had our frame built to use a rear disc, so we can add it if we need it, but so far haven't felt the need.


6th in the Nocatee RR this weekend.

^ Sounds like a reasonable plan. We had our frame built to use a rear disc, so we can add it if we need it, but so far haven't felt the need.


6th in the Nocatee RR this weekend.

Congrats! Good job!

Looking forward to catching up you on the road and talking tandems. It will be 2-3 months before we're actually riding our tandem.

You might want to look at Edge wheels too. Ritterview has had some luck with them.

Yes, I really like my Edge (now ENVE (http://www.envecomposites.com/News.aspx?id=77)) wheels thus far. I just got them back from a warranty repair (a violent and sudden pinch flat tire deflation caused the rim to abrade and the carbon surface to peel (http://www.flickr.com/photos/vonkaenel/sets/72157624809327113/)). ENVE could have called it a 'crash', but didn't.

The deep clincher rim (65 mm (http://www.envecomposites.com/wheels/road/65.aspx)) wasn't selected over ENVE's 45 mm alternative for aero, but rather to fortify the wheels which are limited 28 spokes. The ENVE spoke holes are famously molded rather than drilled, and you don't want to molest your rim by drilling new holes.

With the 28 DT Comp spokes and the deep rim the wheel appears plenty robust for our 305 lb. team. I notice no flex and descend confidently on them. The hubs are DT Swiss 240S disc brake (http://www.dtswiss.com/Products/Components/Hubs/240s/240s-disc-brake-135mm.aspx) and 240S (http://www.dtswiss.com/Products/Components/Hubs/240s/240s-radial-%282%29.aspx).

What is the weight, you ask? I'd wondered myself, and getting the wheels back gave me the opportunity to weigh them (http://www.flickr.com/photos/vonkaenel/sets/72157624974210855/) sans disc and cassette.

http://farm5.static.flickr.com/4112/5053696454_082a270cf8.jpg

http://farm5.static.flickr.com/4106/5053703902_3103c2a32e.jpg

The front and rear are 789 and 929 grams respectively.

Nice wheels Ritterview. I would prefer to use the DT 240 hubs. What is your rear wheel spacing?

You didn't mention any handling issues, I'm guessing 68mm deep wheels are no problem on the tandem in a crosswind.
RP

I would prefer to use the DT 240 hubs. What is your rear wheel spacing?

You didn't mention any handling issues, I'm guessing 68mm deep wheels are no problem on the tandem in a crosswind.
RP

The OLD is 135 mm. I am very glad I chose 135 mm. A bit wider than the 130 mm road standard, and it allows use of the wide variety of mountain bike equipment, which are likewise equipped with triples, rotors, etc.

With wind it can get a bit sketchy. Eventually I will purchase an aluminum rim front wheel for rides with a lot of wind, or tricky descents that would require front caliper braking in addition to the rear disc. Its easy enough to change out a front wheel and brake pads.

The OLD is 135 mm. I am very glad I chose 135 mm. A bit wider than the 130 mm road standard, and it allows use of the wide variety of mountain bike equipment, which are likewise equipped with triples, rotors, etc.

With wind it can get a bit sketchy. Eventually I will purchase an aluminum rim front wheel for rides with a lot of wind, or tricky descents that would require front caliper braking in addition to the rear disc. Its easy enough to change out a front wheel and brake pads.

I think it was a smart decision to go with 135mm. You open yourself up to a ton of options.

However, my 145's have taken quite a beating with no issues, and they aren't crazy heavy. Though if I could do it again (and spend a bit more dough), I might have gone 135mm with your exact rear wheel, but with my current front wheel.

Homey, what width hub are you running on your Calfee?

135mm Sorry, I missed that.

Nice wheels Ritterview. I would prefer to use the DT 240 hubs. What is your rear wheel spacing?

You didn't mention any handling issues, I'm guessing 68mm deep wheels are no problem on the tandem in a crosswind.
RP

I think that deep section wheels have less of an effect on a tandem, than a single, due to the longer wheel base, and added weight.

The only time we've had any issues with the 808's was time trialing with aerobars in a significant cross wind, and it was still manageable.

I think that deep section wheels have less of an effect on a tandem, than a single, due to the longer wheel base, and added weight.

The only time we've had any issues with the 808's was time trialing with aerobars in a significant cross wind, and it was still manageable.

Homeyba, what say you about winds and deep section rims on a tandem? On RAAM, if the winds kicked up, would the Zipps be doffed? The front only, or both?

[QUOTE=merlinextraligh;11574549]I think that deep section wheels have less of an effect on a tandem, than a single, due to the longer wheel base, and added weight.



This is what I was wondering. Sounds logical. Deep wheels, here we come.

Good posts everyone. Thank you! I now may go 135mm rear spacing too. More hub options, and I can get a cheap set of 29er wheels for everyday abuse.
RP

Homeyba, what say you about winds and deep section rims on a tandem? On RAAM, if the winds kicked up, would the Zipps be doffed? The front only, or both?

I had problems with the HED3 wheels and wind. It wasn't so much blowing the bike all over the place (though it did move a little as the Zipps do) but it caused the bike to wallow and if I hit a bump or somthing upset the bike at all it would become a shimmy which gets a little exciting at 50+mph. That may have had more to do with the interaction between the HED3's and my really stiff frame. The Zipps haven't given me too much problems in the wind. All of our tandems had Zipp 404's on them for RAAM. I don't remember there being any significant wind issues. Gusts of course are much more problematic than sustained side winds. When I get home tonight I'll post a pic of some of the side winds I've ridden in, yes you can actually see the wind, or all the sand in it...;)

Here you go. Zipp 404's in a slight side wind.:lol:

172692

btw here's a pic of us in RAAM 09 with the HED3 wheel on there.

172693

I created a post about using a 28 hole 145 DT swiss 240 hub a few months ago. Shouldn't be too far back. I too have the Edge 65 clinchers. I'm quite happy with them. I (self) built them up and have not even had to true them post build. (~700-1000 miles on them) Radial lace spaim front, 2x butted/aero rear. I do a quick tension check on my wheels every time I swap tires, balance them if need be and keep a spoke tool/spares in the seat post. (though, I've never needed them) Team is roughly 300lbs 4 bottles of water, 1lb tool bag, 25-27lb(I forget?) bike. It's pancake flat here in TX, so no real worry about making the rims hot. In wet weather, it's pretty hard on the DT Swiss yellow pads. I wore them quite a bit in a 70 mile rain ride.

I had to warranty a edge wheel right out of the box, the braking surface had an overlap and would have a 'thump thump thump' on the front wheel. They took care of it, no problems since.

*IF* doing it again, I'd seriously look at Reynold's new wheel this year. Probably the SDV66, they changed the epoxy compound to better handle higher heat. Edge(ENVE) may have also, I've not read any 2011 reports.

The new Cyfac tandem was built with 135mm spacing to make it easier to build a fancy rim, I'll simply re-dish my current rim, switch axles and call it done. I haven't decided what I'm going to do for it's debut at the show; I'll come up with something when I get me hands on the new frame...

-Brad

I had to warranty a edge wheel right out of the box, the braking surface had an overlap and would have a 'thump thump thump' on the front wheel. They took care of it, no problems since.

*IF* doing it again, I'd seriously look at Reynold's new wheel this year. Probably the SDV66, they changed the epoxy compound to better handle higher heat. Edge(ENVE) may have also, I've not read any 2011 reports.

In wet weather, it's pretty hard on the DT Swiss yellow pads...



My problem was with my rear wheel, I sent ENVE my front wheel too only because I wanted the new ENVE stickers to match front and rear. Imagine my surprise when they warrantied my front wheel too, as they found uneveness in the rim. :thumb: I think it was there from the start, as I had commented on front wheel brake chuddering in a first ride report post (http://www.bikeforums.net/showthread.php?625417-Woo-hoo-my-Calfee-won-quot-Best-Tandem-quot-at-NAHBS!&p=10541896&viewfull=1#post10541896). Lets just say that ENVE's wheel customer support >> a prominent tandem manufacturer's.

I discussed the new rim with Jake at ENVE. The new rim is improved, as it has a new heat resistant epoxy. Sounds like what the Reynolds is doing.

ENVE has their new recommended gray brake pad (http://www.envecomposites.com/accessories/brakepads.aspx), which should probably be used in lieu of the Swiss Stops.



I would prefer to use the DT 240 hubs... I now may go 135mm rear spacing too. More hub options.

Once you go to 135 mm, then a myriad (http://fairwheelbikes.com/hubs-mountain-hubs-c-123_124.html) of hub options present themselves. DT 240's have their merits (eg, reliability, ubiquity) but there are other hubs that might make for a stronger wheel. You can see how DT stacks up against other boutique hubs at the epic Fairwheel Hub Review (http://fairwheelbikes.com/forum/viewtopic.php?f=65&t=6940).

Ritterview - I cannot reply to your personal message. This site tells me I have not had enough posts to do the personal message thing. I wanted to let you know that I am not ignoring your request. I'll get a post up about some bike details soon.

Here you go. Zipp 404's in a slight side wind.:lol:

172692

btw here's a pic of us in RAAM 09 with the HED3 wheel on there.

172693

I guess with the HED3 wheels, the tumble weeds will go right through.

I guess with the HED3 wheels, the tumble weeds will go right through.

Actually, I think it'd chop them up into little pieces. Those blades are pretty sharp... ;)

Ritterview: I have EDGE 45C with Chris King R45 on my single. They are nice. I am in need of new wheels for our Calfee tandem and was looking at the 45s. We are about 280 lbs at our max weight. Three questions: Do you feel the 45s would work for us? What lace pattern and guage of spokes did you use? Lastly, I was calculating the weight to be about 1550 and was curious if your scale was accurate at 1718?

Ritterview: I have EDGE 45C with Chris King R45 on my single. They are nice. I am in need of new wheels for our Calfee tandem and was looking at the 45s. We are about 280 lbs at our max weight. Three questions: Do you feel the 45s would work for us? What lace pattern and guage of spokes did you use? Lastly, I was calculating the weight to be about 1550 and was curious if your scale was accurate at 1718?

I think my scale was pretty darn accurate, as it is just about the same as calculated by the Wheelbuilder.com Wheel Weight Calculator (http://www.wheelbuilder.com/store/wheel-weight-calculator.html). The 65 rim is of course heavier than the 45, and I used the heavier DT Comp spokes. I'll get back later on your questions, in the meantime please calculate your proposed build using the Wheelbuilder tool.

http://farm6.static.flickr.com/5252/5556176099_fd2f0035b1_b.jpg

Both: 1718 grams, Rear: 929 grams, Front: 789 grams.

http://farm5.static.flickr.com/4112/5053696454_082a270cf8_m.jpg http://farm5.static.flickr.com/4133/5053082847_cc0f4d22a1_m.jpg http://farm5.static.flickr.com/4112/5053694954_48e476db33_m.jpg http://farm5.static.flickr.com/4105/5053072083_7315417115_m.jpg


Edit:


Ritterview: I have EDGE 45C with Chris King R45 on my single....Do you feel the 45s would work for us?

Are you thinking of harvesting the EDGE 45 clincher rim from your half-bike? I don't think that is a good idea. You'd be better off selling the 45 wheelset whole, and using the proceeds starting from scratch with your tandem wheel.


The 45 comes in 20/24/28 holes, and yours would need to be 28.
If you took the rim off your half-bike wheels, you'd be left with a CK R45 hub and spokes with no where to go.
ENVE has recently changed the composition of their rims to make them more heat resistant. Since caliper brake heat is the Achilles Heel of carbon tandem rims, on any caliper-exposed rim you'll want the latest-greatest heat resistance that ENVE has to offer.
The 65 rim is deeper and therefore stronger than the 45. According to Sixtiescycles (http://www.bikeforums.net/showthread.php/714528-Paketa-V2r?p=12328670&viewfull=1#post12328670) rim depth greatly increases wheel strength. My 65 rim with DT comp spokes appears strong enough, I do not know if the same would be true for 45's.


My use of the 6.04 g DT Comp spokes in lieu of 4.36g Sapim CX-Ray spokes adds 94 grams. If you'd like the wheel to be lighter you can discuss with your wheel builder whether the 45's or lighter spokes is advisable. I took the lead on my wheels from Jason at Fairwheel (http://fairwheelbikes.com/), who wrote the definitive hub review (http://fairwheelbikes.com/forum/viewtopic.php?f=65&t=6940), and knows whereof he speaks.

I plan on a complete new build for the tandem as I love the 45s on my on the half-bike. I went to the wheelbuilder sight you recomended and confirmed your numbers and the difference with my calculations were mostly the spokes I selected and the weight of the 65 vs 45.

I am looking for light and strong, who isn't, as we ride the Tandem with the local race team training rides and the accelerations and hills are our toughest challenge of staying with the peloton.

Thank you for your help - I will consult my LBS and ENVE before I pull the trigger.

Do be careful with too deep of a rim. With the wider axle on the tandem it can increase the angle of the spoke resulting in a wheel that is actually weaker. Definitely consult ENVE before you buy. They will make sure it's the right application for you. I know that Zipp was very concerned about the angle on the 808. The 65 is shallower so it may be just fine. Something to keep in mind though.

I plan on a complete new build for the tandem as I love the 45s on my on the half-bike. I went to the wheelbuilder sight you recomended and confirmed your numbers and the difference with my calculations were mostly the spokes I selected and the weight of the 65 vs 45.

I am looking for light and strong, who isn't, as we ride the Tandem with the local race team training rides and the accelerations and hills are our toughest challenge of staying with the peloton.

Thank you for your help - I will consult my LBS and ENVE before I pull the trigger.
Wouldn't accelerating and hillclimbing be the very things that a set of deep rimmed carbon wheels will not help you with?
Also when you do the maths saving even a few 100 gms in wheel weight has minimal effect in accelerating and climbing on a single bike, and that small amount will be almost halved on a tandem.

Dean V - Short answer - the deep v won't help or hurt hill climb or acceleration. Deep V is a stronger design and therefore when coupled with carbon for weight savings it becomes a great solution from a strength to weight ratio perspective.

My 20 years of tandem experience on aluminum rims has proven this to me. I have used 32f and 36r hubs with Mavic open pro rims weighing 1600 gr. They were nice and light but I would only get one season, sometimes less, out of them. They would crack or I would pull the spoke out of the eylet. I switched to the Velocity Deep V and Fusion rims weighing 1900 gr and they are lasting 3 to 4 years and the braking surface reduction is generally the cause of their demise. If I can get the close to the strength of the Velocity rims at 1500 gr then I am golden!

The math clearly shows the advantage that weight reduction has in acceration and climbing. How much it is worth is a value judgement and is closely tied to the application. Example - In crit riding or racing applications where attacks occur often there would be greater benefit from lighter wheels than touring around the countryside from bakery to bakery. A good perentage of my riding is in a group that is looking to select the weak riders off the back.

I am not interested in a philisophical debate on this subject as this board has beat this one to death several times. I am interested in discussing the experience others have had with carbon wheels and their tandems to help me make my own choices. Please don't respond in an attempt to pick my reasoning apart or prove your own bias or value of light tandem wheels.

...Please don't respond in an attempt to pick my reasoning apart or prove your own bias or value of light tandem wheels.


Good luck with that one! ;);)

Are you looking at an all carbon rim like Ritterview has or a carbon rim with aluminum brake liner or does it matter?

They aren't deep, but I just got a set of HED C2 "Belgium" rims for the PowerTap wheel build for my half bike.

They are 23mm wide (24mm deep), and still only 475g. With a 23mm clincher, the tire is more flush with the wider rim, and less ballooned out, creating a tire profile similar to a tubular. So far the handling and ride feels great. HED even claims they are more aero that narrower rims, since the tire/rim surface is flatter/more continuous.

http://www.wheelbuilder.com/store/hed-belgium-c2-clincher-rim.html

I with they had a 36h option. I think It would make a nice tandem rim.

Here is a response that I received from Richard at Wheelbuilder.com about wheels with deep carbon rims.

"Wayne,
Thank you for your e-mail. Zipp no longer makes the 404 with spoke counts higher than 24. After SRAM purchased them the company decided to stick to only the popular rims that do not give them any warranty issues. With that void in the market there are no aero wheels available that will accommodate higher spoke counts unless they are disc brake specific. If you have the option of going with a disc brake setup I would recommend the ENVE composites 66 all carbon clincher. If you use rim brakes it is not a good idea to build an all carbon clincher because the brakes will overheat the rim and melt it.

Let me know what you think about the brakes and we can figure out how to configure your wheels."

I am not planning on using disc brakes, so for the time being I am watching and waiting to see what develops. The guy I talked to at Nimble told me that in the next 6 months of so they will have a light weight high spoke count wheel available that would be light and strong enough for tandem use, and reasonably priced. It will not be a deep dish carbon rim though.

If you use rim brakes it is not a good idea to build an all carbon clincher because the brakes will overheat the rim and melt it.

...I am not planning on using disc brakes...

Rich at Wheelbuilder is a great resource, because he knows tandems as well as wheels. He makes the wheels for Calfee. I had corresponded and talked to him, but eventually my wheels were built at Fairwheel (http://fairwheelbikes.com/), along with the rest of my bike. He was convinced I was going to melt my front rim, even with a disc (I haven't yet, Rich!).

Rich, however, is no geography whiz. You are in Central Illinois. if you melt your rims in Central Illinois you should get a medal. The Century rides (eg (http://connect.garmin.com/activity/42619170)) on Garmin Connect in Central IL will have something like 2000 ft of ascent/descent, and the biggest hills are less than 100 ft. Wasn't Central Illinois the setting for the biplane scene in North by Northwest? Flat.


Illinois is flat (http://www.city-data.com/states/Illinois-Topography.html). Lying wholly within the Central Plains, the state exhibits a natural topographic monotony relieved mainly by hills in the northwest (an extension of Wisconsin's Driftless Area) and throughout the southern third of the state, on the fringes of the Ozark Plateau. The highest natural point, Charles Mound, tucked into the far northwest corner, is only 1,235 ft (377 m) above sea level—far lower than Chicago's towering skyscrapers. The low point, at the extreme southern tip along the Mississippi River, is 279 ft (85 m) above sea level. The average elevation is about 600 ft (183 m).

I'd not relish cycling in such a flat area, but there is one benefit. You can have carbon rims with calipers. If you are to encounter any terrain with the least possibility of melting your rims, you can substitute an aluminum rim wheel on the front for that ride.

Here is a response that I received from Richard at Wheelbuilder.com about wheels with deep carbon rims.

"Wayne,
Thank you for your e-mail. Zipp no longer makes the 404 with spoke counts higher than 24. After SRAM purchased them the company decided to stick to only the popular rims that do not give them any warranty issues...

That's not entirely true, see mine below. Zipp will custom drill rims. They won't do one or a pair. They want their reps to buy them in 10's and Wheelbuilder isn't going to buy 10 of them so that you can have two.
http://i224.photobucket.com/albums/dd35/Homey-B/CIMG1074.jpg

That's not entirely true, see mine below. Zipp will custom drill rims. They won't do one or a pair. They want their reps to buy them in 10's and Wheelbuilder isn't going to buy 10 of them so that you can have two.
http://i224.photobucket.com/albums/dd35/Homey-B/CIMG1074.jpg

And to further confuse things, Zipp is custom drilling 2 rims for my wheel build as we speak. (different wheel builder though)

I just launched an email to my LBS requesting him to propose a solution for strong light full carbon wheels. Either 45s , 65s or a mix of both if necessary. I will report back with what he proposes. Thank you all for your help so far!

The math clearly shows the advantage that weight reduction has in acceration and climbing. How much it is worth is a value judgement and is closely tied to the application.

My old racing club was well-populated with Silicon Valley engineer types who loved looking at just this problem. Their assessment (for singles, but should hold for tandems) is that weight reduction was less useful than commonly thought, but that drag reduction was more useful.

In short, weight reduction is good, but don't do it if you're going to significantly compromise aerodynamics.

FWIW.

Zipp is custom drilling 2 rims for my wheel build as we speak.

Has Zipp specified that they will warranty wheels for a tandem? Their FAQ say no. The warranty was no small matter with my rims when a tire blowout delaminated the rear rim (http://www.flickr.com/photos/vonkaenel/4979772347/in/set-72157624809327113/). ENVE warranted my rear wheel, and my front too (for brake track uneveness). ENVE has no weight limit and tandems are welcome.




What are the recommended rider weight limits for Zipp wheels? (http://www.zipp.com/support/faq/faq.php)

We generally recommend our maximum limit at 275 lbs. That is not to say that every Zipp wheel is right (or wrong) for you. We strongly believe in having the right wheel for the right application. The needs of a 220 lb sprinter are different from those of a 115 lb triathlete. If you are at or above 190 lbs, we strongly recommend you consider the MAX 404 or 808. These wheels have additional spokes that offer better stiffness and cornering confidence for someone at that weight. Keep in mind - this is a guideline. There are very strong riders at 180 lbs who may prefer the MAX, and very smooth-riding 225 lb riders who may prefer the standard wheel.
Recommended maximum weight for specific wheels:

190 lbs (86kg) for 202 and 303 tubular
225 lbs (102kg) for Team Issue, 404, 808, and 1080
Above 190 lbs (86kg), consider MAX 404 and 808
275 lbs (125kg): Cyclocross, MAX, Track, Disc wheels

Note: Zipp wheels, rims, and hubs are NOT warranted for use on tandem bikes.

They specifically state that they will not warranty wheels used on tandems. They did replace my rear rim last year though when I cracked it hitting a pot-hole at 50+mph.

Has Zipp specified that they will warranty wheels for a tandem? Their FAQ say no. The warranty was no small matter with my rims when a tire blowout delaminated the rear rim (http://www.flickr.com/photos/vonkaenel/4979772347/in/set-72157624809327113/). ENVE warranted my rear wheel, and my front too (for brake track uneveness). ENVE has no weight limit and tandems are welcome.
No warranty as you clearly noted.

They specifically state that they will not warranty wheels used on tandems. They did replace my rear rim last year though when I cracked it hitting a pot-hole at 50+mph.

So, they will not warranty tandem wheels, but did yours. Do you not volunteer that it is from a tandem, and leave Zipp to figure out the significance of the 145 mm hub, the Avid 203 mm disc, and the 32 spokes?

I believe that the mechanic just sent the rim back because he used all the parts to rebuild the new wheel. I'm not sure if he mentioned it was on a tandem. They may have replaced it because they are one of our sponsors. ;) I would imagine that if you sent a rim in and didn't say what it was on they wouldn't know. Not very honest though.

Zipp has been pretty good to me with crash replacement pricing on older wheels that were out of warranty on my single.

I bet that if you were straight up with them about the Tandem issue, they'd likely give you decent crash replacement pricing, event hough its not covered by warranty.

My new wheels are on order and should be on the road in two weeks. Enve 45, Aerolite spokes and Chris King hubs. Thanks for the help.

Lot's of good direction in this thread. I'd add that the performance of caliper brakes varies with the depth and type of rim. Deep section alum rims dissipate heat best, say 30 to 38mm. Normal section alum rims like the dyads have just an average heat dissipation, and Carbon rims of any depth the least. Thus the wheel builders advice to for carbon rims that one might melt pads. For Indiana I suspect any rim will suffice for heat dissipation since you don't have long descents.

My new wheels are on order and should be on the road in two weeks. Enve 45, Aerolite spokes and Chris King hubs. Thanks for the help.

And we never found out how Bscheidt liked his wheels! :(


Lot's of good direction in this thread.

And its a shame we didn't find out. If these wheels were built for your 130 OLD T-tandem, they'd be plenty light. It'd also certainly put the new anti-melting rims to the test descending in the Rockies.

http://farm9.staticflickr.com/8108/8659109399_fc40321f84_z.jpg

Hey guys sorry for my lack of final outcome. As a recap, we used the ENVE 45 rims, DT bladed spokes and Chris King ISO rear and Classic front hubs. We have about 17,000 miles of use. We use an aluminum rim set from November to mid march for better braking and lower replacement cost if damaged by road debris. We could not be happier with the rims and wheel build as they have been flawless and have delivered the light weight, stiffness and aerodynamic properties we desired. The rear ISO hub as been a disappointment as it has