bradcycles

i am getting a new calfee tandem built up with trp thru-axle fork and WI cld thru-axle hubs (front and rear). it will have 180mm disc on front, 203 mm disc on back, and will have the new shimano hydraulic brakes.

i am considering 2 potential wheelsets - the enve 3.4 disc clincher wheelset (made specifically for disc brakes) and the zipp 404 wheelset. i talked to enve today, and even though the enve 3.4 disc clincher wheelset is only 24 spokes (front and rear), the person i talked to thought it would be plenty strong for a tandem with hydraulic disc brakes (with the WI hubs with 3x lacing). he said the enve 3.4 disc clincher was lighter than normal enve 3.4 due to taking out the brake track, and they also made it stronger for disc brake application.

but, the enve 3.4 rims are only 35mm depth in front and 45mm depth in rear, compared to the zipp 404 depth of 58mm front and rear (with similar rim width and shape). but, the zipp 404s are not disc specific, and they have the brake track, so are presumably heavier and maybe not as strong.

what are thoughts on the best wheelset? i would preferably want something that is as aero as possible, as wide as possible (for 28mm tires), and sufficiently strong for the application.

thoughts on pros/cons of each wheelset?

chojn1

Quick questions:
How did you narrow your ENVE choice to the 3.4?
Why eliminate the SES 4.5 or 6.7 if you want a thicker rim?
Why eliminate the mountain or XC rims as they are lighter, have the more hole counts, and fit wider tires?
Just want to pick your brain on your decision process.
Thanks,
CJ

twocicle

you are scaring me

bradcycles

there is only one enve SES rim that is disc specific - that is the enve 3.4 disc clincher (different from the standard enve 3.4 clincher). there is no disc-specific enve 4.5 or enve 6.7. i would prefer a deeper clincher (like the 6.7) that would work for this tandem application.

others have said that 28 spokes minimum are needed for tandems with disc brakes. from talking to the guy at enve, he thought the enve 3.4 disc clincher rims (with only 24 spokes front and rear) would be strong enough for tandems with disc brakes. they are stronger and the layup is different from the standard enve 3.4, enve 4.5, and enve 6.7.

i think the XC rims would also work, but i think they are even less deep (and less aero) than the enve 3.4 rims.

bradcycles

too few spokes? or overthinking wheels?

Ritterview

You talked to ENVE, about tandem rims, and they were helpful.

What if you talk to Zipp?

They may just recoil from you like Dracula from the cross, as soon as you mention the word tandem.
When under warranty, my rear ENVE rim delaminated after a blow out, ENVE cheerfully replaced rims and rebuilt both wheels.

If ENVE shows tandem love, while Zipp's countenance is cool disdain, if you are on fence, why go with Zipp?

TooMany

As a long time lurker on this forum (thanks all for your insight into tandems), I finally have something to contribute. I recently went through this process as well: quick notes - new Landshark, Whiskey Fork, Ultegra Di2, hydraulic discs. In other words, a very similar build to a number of recent Calfees noted here.

I went with the XC rims option for one reason mostly: They are 30 mm wide and I chose greater tire volume over a marginal aero benefit. A 28 mmm tire doesn't bulge outside of the rim at all. We all remember when a 30 mm rim was considered deep.

Bradcycles, you are in Portland. I bought my wheels from Cyclepath on MLK. They import a hooked all-mountain 29er rim that is 30mm outside width (25 mm interior) that you can get in a variety of hole drillings and they are $280 per rim. You can get two sets for the price of that Enve set.

twocicle

Depth adds rim strength, but while this is a major factor it is not the only one. When reducing spoke count, matching with deeper rims will reduce spoke length which adds strength. Review the ERDs of each rim and note how the difference in rim depth x 2 closely mirrors the ERD. For example, the 3.4 35mm rim ERD is 2cm larger than the 45mm rim. The 6.7 60mm rim ERD is another 3cm smaller (total of 5cm smaller) inside. It should be clear that longer spokes will not build as stiff a wheel.

The accepted standard trend I have observed is for disc 29er wheels to be 24 spokes, where their non-disc counterparts are built with 20. That is for single bikes, one rider, sub-230lbs. For a dual horse tandem, build what they call a clydesdale setup for singles.

Don't bet the farm and buy the farm. Be safe my friend.

akexpress 

What tire pressures are the mountain and Xc rims rated for as that may eliminate their application if you plan on running over 100 lbs of tire pressure as those rims are usually ridden with less then 40lbs and even less with tubeless conversions.

chojn1

AK,
The ENVE XC spec 100lb max pressure with a 28mm wheel and 50lb with a 1.9in wheel. I understand they are not aero/deep enough for the Brad's need. What is your opinion on how lower pressure larger tires affect road tandem handling?

Brad,
Does Zipp make disc specific 404 rims? If you eliminate the 6.7 for having a brake track, why consider the Zipp?

bradcycles

The enve 6.7 wheels have only 20 spokes front and 24 spokes rear. Enve not only eliminated the brake track from the enve 3.4 disc clincher, but they changed the layup of the carbon fiiber to strengthen it for the stresses of disc brakes.

The zipp 404 rims are not disc specific, but they do have 28 spokes. I also understand pther tandem riders have successfully used these tims with disc brakes.

I would prefer the enve 6.7 wheels if i got assurance that they would be strong enough for a tandem with hydraulic disc brakes.

chojn1

Thanks for sharing your thoughts.
That helps with my own research.
CJ

twocicle

... and so which component resides between a disc hub and rim? Spokes. If ENVE had to make specific allowances to strengthen the rim for disc usage, why assume a similar allowance is not needed for spokes?

DubT

My perception is that disc brakes put a greater load on the spokes than rim brakes, therefore more/stronger spokes would be required for a disc brake setup.

DubT

With your choices the Enve wheels sound like the best choice. Ritterview has had excellent results with his! If ENVE will provide warranty on a tandem and Zipp will not then for me the choice would be made. Since I do not use nor need disc brakes I use HED 3 wheels and do not have to worry about conventional spokes and wheel truing.

waynesulak

I assume you meant to write 100 psi max pressure with a 28mm wide tire and 50 psi with a 1.9in (48mm) tire.

Good info and illustrates wider tires pressure on rim walls.

What pressure do you run on your Hetre's?

joe@vwvortex

I'm curious as to why everyone feels it's acceptable to run 180mm front discs and 203mm rears? With the majority of the braking happening with the front wheel - I can't see why anyone would do this from a braking improvement perspective. I guess if you are a really light team it possibly could make sense. Is it simply because of the fork choice?

akexpress 

Because of fork choices there are very few carbon forks disc brake ready and then even fewer with a thru axle. The Whisky fork only has room for a 180mm rotor. The hydraulic brakes are significantly improved in modulation and power so the 180 is IMHO more powerful then a rim brake. I appreciate your thoughts about the front wheel doing most of the brakes however on a tandem I think is a bit more even between the front and rear. I would love to have a 203 in front also but it is really all about the fork choices.

Dean V

What sort of performance gain do you expect to get with either of these wheel sets compared to a 32 spoke wheel and a good aluminium rim?

joe@vwvortex

I guess I feel the same way about through-axles. I would love one on my tandem - but I won't give up my 203mm rotor just to get one. Hence I'll stick with my Woundup fork until someone finally makes a through-axle fork for a tandem that can accommodate a 203mm rotor. You will get more power through increased friction and hence you will generate more heat - bigger rotor will deal with more heat better. Use higher friction brake pads to compensate for the smaller rotor diameter - create more heat. I would argue that the tandem wouldn't be much different than a single in terms of weight distribution - since traditionally more weight is on the front as the captain is usually larger than the stoker. Who knows if it will work or not - and hopefully it will for you. For me though - there is never enough brake.

I've been through this on two race cars. Ultimately - I had to go to bigger rotors (in the front only) to get the braking I needed - because I was getting caliper temps way above what they could handle. Yes - know its not a bike but the same theories apply.

bradcycles

a significant aerodynamic advantage with the zipp 404 (less so with the enve 3.4 wheels). of all the parts and bikes i've ever purchased in riding road bikes the last 15 years, the biggest performance gain i felt of any single part or bike was when i purchased my enve 6.7 clincher wheels. i could tell that i was faster any time i was pushing the pace in the wind. i have the enve 3.4 clincher wheels on another road bike, and i can tell the aero advantage is not as significant with those wheels.

waynesulak

For me the cost/benefit of performance parts is completely dependent on the user. Long ago I read Greg Lemond who had written something to the effect that for recreational cyclists or racers just starting out better parts make very little difference but at the top level of the sport where the riders are all in top shape it can be very important. I like that remark because it acknowledges real benefits but puts them into context.

Yesterday we were doing some intervals on a route that runs out and back north and south. A common 20++ mph south wind was blowing so we used the upwind leg for the interval and the downwind for recovery. On the third trip into the wind I was gassed and struggling but looked at the computer to see it was our fastest leg by at least 1.5 mph.

After the ride I congratulated my stoker for really putting out the power on that last trip and she replied that she went just as hard on previous intervals but that was the trip that she stayed in the drops the entire way.

Dean V

How can you "feel" a bike is faster? Can you perceive that you are now going 0.5mph faster for the same effort due to an equipment change? I have ridden a fair bit on Zipp 404s, 808s etc. No doubt they feel different to a shallow wheel and I don't doubt they are faster but as to how much I wouldn't be sure. Couple of other things to consider with a tandem is that any aero advantage from wheels is almost half what it would be on a single bike. Putting a 28mm tyre on these wheels will reduce this advantage even more. Also unless you are racing other tandems you usually end up trying to keep up with single bikes and here the limiting factor is always hill climbing speed, not aero.
Yesterday I actually tried to test some of my bikes to see if I could measure any aero advantage. This was around a velodrome. 20 laps/9km with each bike. Not too fast just a pace I could hold steady.
1- 34.9kph @ 232w. Giant TCR with Zipp 404s.
2- 35.8kph @ 231w. Giant Propel (aero frame) with Zipp 404s
But then,
3- 35.7kph @ 232w. Old Pinarello Dogma FPX with shallow box section alloy rims (Campag Nucleon).
The point is this aero stuff can be confusing and I think some of the differences are not as great as what the marketing people would tell you and what you may "feel".

bradcycles

not only did it "feel" faster to me, but i started performing much better and winning my local lunchtime crit in the bay area more often. several of the guys in my lunchtime crit started talking about the unfair advantage that my wheels were giving me (my fitness was also peaking at the time, so i think it was a combination of the wheels and my fitness). more and more of the guys starting showing up at the lunchtime crit with aero wheels. you can also look at all the aero testing that is published showing the advantages of these wheels (so there is the hard data in addition to the "feel"). the aero advantage is more significant at higher speeds. our lunchtime crit would often average between 25-30mph for 40 minutes. the aero advantage mostly kicks in if you are the one doing the attacking, riding off the front, or at the front. if you are one to draft behind others, it's not going to make as big of a difference.

on a tandem, i think the aero effect would be even more significant. due to a 70% increase in my power on the flats relative to riding by myself, we are able to maintain higher speeds on the flats than i can by myself, so the aero advantage is enhanced. when my stoker and i were in peak shape, we showed up to a local fast noon ride that went over rolling and flat terrain, and by halfway through the ride, by riding at the front, we had burned off 13 of the 15 people on the ride (all of them were on single bikes). and, this was on our tandem with non-aero wheels. if we had the aero wheels, we would have been even faster on the flat and rolling terrain.

chojn1

I am running Babyshoe extra light at 45lb per square inch.