merlinextraligh

We did the local time trial series on the Tandem last night. I'm finding I like time trialing on the tandem better than on my single bike.

The teamwork aspect of it is rewarding, the shared suffering and support helps, and you're not fully accountable yourself for a bad time.

No other tandems were there, so no apples to apples comparison, but we did have the second fastest time (although the guy with the best time, a local Cat 1 with the course record, put a minute on us.)

We ended up at 14:52 for the 6.5 mile course.

The rest of you that time trial on your tandems, thoughts about aero set up on the tandem, wheels and other equipment, pacing, any other issues unique to time trialing on the tandem?

oldacura

I'd like to give time trialing a try here but I think most of them around here require signing up in advance and they fill up early. I'd like to be able to just show up and give it a shot. We're not very good at planning.

Congrats on your time.

diabloridr

We've only done a few TT's on the Speedster: Pinole at least twice and some flat rectangle up by Winters come to mind. No great results to brag about, but good experiences. Our training partners won the tandem category at Pinole one year we rode so that was cool.

We just leave the Rolfs on and slap a clip-on aerobar on. Pull off the 2nd water bottle cages for both riders along with the bags and pump.

I dust off my old skinsuit and lycra booties for the occasion.

More serious riders would likely swap out to a disk and tri-spoke on the flat courses.

DubT

We (a teammate and I) rode the 1993 Nationals and placed third in the 90+ age group. We rode our 1989 Santana Targa with Zipp wheels, full disc on the rear, a deep carbon rim with 32 spokes on the front, clip on bars, skin suits and Bell time trial helmets. Our time was 58:42.

Wayne

zonatandem

Have done a few TTs way-back-when.
Did our first in Arizona in 1978 or '79.
Recall Colin Laing, our starter, saying 'how do you want me to hold the bike?'
Instructions between Kay and Rudy: 'Tuck in and go like hell for 20 miles!'
Aero equipment: none.
But we did have one of the lightests tandems at that time, a 34 lb. custom very short wheelbased (60 and 1/4 inches!) machine.
No other tandem competition, but did manage to pass a single!
Sort of fun to recall!
Pedal on!
Rudy and Kay/zonatandem

Dean V

Here are some pics of our Cannondale as it is at the moment.
I made the handlebars for the stoker and she seems to be happy with them. The higher bars are just to give another option for when we aren't actually riding the TT. The Adamo saddle helps me get a bit further forward and gives a bit more room in the back.
I can't think of anything peculiar that we do for a tandem TT. Just take off quickly, but not too fast, and then settle into a pace that we think we can hold for the distance. There is no talking on the ride! The TT we do fairly often is a flat 9.8 mile out and back course. We are usually between 25 - 27 mph and our best time is a 21m50s. So our speed would be similar to yours.
I have noticed that our times are affected (slower) more on the windy days than the solo riders.
I also prefer riding the TTs on the tandem to solo.

rhino919

Good effort

Since you say you have TT'd on your single, I am assuming that you already understand all of the basics (clothing, position, etc.) If not Google "cycling time trial technique" for lots of good info.

We haven't done a lot of time trials, but have competed against some really fast teams. It is obvious that they have spent significant time and money optimizing their position and equipment.

One of the main advantages of a tandem for going fast is having the stoker hidden from the wind. I doubt you will find any articles online, but you can find images by searching for "tandem time trial". Those may give you some ideas on position for the stoker.

For aero wheels, most of the rear discs we have seen have been homemade, since most tandems have 145mm or wider spacing. I have thought about making my own disc and have found some good info by Googling "DIY Disc Wheel". Wheelbuilder.com also has premade aero wheel covers, but they aren't supposed to fit tandem wheels. You might be able to make it work if you ordered two sets and used the non-drive cover from each.

Otherwise, I don't find anything unique about TT'ing on my single vs. the tandem. I dislike both equally

StephenH

I've thought about doing one here locally. But it requires one-day license for each plus entry fee, so you're looking at $80 or $90 to go ride 13 miles, which is a bit steep. Whether we'd do any good would just depend on if there was a lack of competition.

merlinextraligh

A couple of areas where the tandem raises unique issues appear to be wheels, and aero position for the stoker.

For wheels, we jsut used the Rolfs wednesday. We have used a trispoke front, and a disc wheel cover for the back before. We also have used Zipp 808's that were built with extra spokes, and a tandem 145 mm hub.

Doing the same series each week we'll be able to try different combinations. Of course it won't be very scientific with changing conditions each week.

I go back and forth on whether the Tri spoke or the 808 is faster. My bet is the tri spoke might have slight advantage, given that our "808" has more spokes than normal and doesn't use Sapim spokes. However, I'm a bit leary of the Tri spoke with a team wieght of 350lbs.

For the rear, the disc cover doesn't work well, because it has to be cobbled to not buckle on a 145mm hub. I've got a HED disc, but it's 130mm spacing.

Dean, IIRC, your disc is 130mm, with some custom work on your derailleur hanger to fit it in wider spacing. What brand is it, and do you mind saying what your team weight is?

DubT, how did you handle the rear spacing issue with the Zipp disc. Currently Zipp reccomends a maximum 275lbs for rider weight for its discs so we'd be pushing that.

I'm also thinking about trying this: https://www.ttflywheels.com/index.html. It's essentially a reincarnation of the old J Disc. I believe they can put their cover on your wheel, so I could get a reasonably priced spoked wheel on a tandem hub, and have them cover it.

One previous iteration of our bike in TT form:

merlinextraligh

Very cool! Nice to be able to say you placed at Nationals.

We're going to Masters Nationals this year. I figure we need to get in that 58 minute range to be respectable.

Long term goal is to improve enough to see if we can be really competitive in 3 years for 110+

Dean V

Our disc is just an old locally (New Zealand) made one. It is basically a 3/4" foam core with an aluminium tubular rim and a wood centre. This has a fibreglass laminate on each side and the hub bolts into the centre. It used to take a screw on freewheel but I modified a modern cassette hub to fit and also added the disc brake as I didn't like braking on the fibreglass with a rim brake.
We did use a Mavic lenticular disc for a while but it wasn't up to it and started to fail. We have a team weight of 300lb.
I also use a double chainring so the chain line matches up with the 130mm rear wheel.
I don't think there will be anything in it as far as speed difference between the 808 and tri spoke. Use whatever you are comfortable with.

DubT

The 1989 Santana Targa was one of their racing models and it came with 130mm rear spacing. It was an 8 speed setup. My team mate was 6'6" and weighed around 200 pounds so our total weight was around 350. The Zipp disc has thousands of miles on it and still seems sound.

Wayne

teamdonterri

I know what you mean about the teamwork of the tandem in time trialing. We did the Palm Desert Century in November that had a 15mile up hill time trial to Chricao Summit from mile 35 to 50. Also no other tandems to compare to so we won the class, but we managed nearly 15mph at an avg grade of 5% for the course. There was some suffering but we found it quite an acheivement as a team to do.

colotandem

I think you can just show up for the Boulder TT series. The one that goes from Lyons to Boulder. Or at least you used to be able to do that. We did the Cherry Creek series a couple of years ago. Good painful 25 min on the bike!!!

Clip on aero bars, Rolfs, remove bottle cages, booties and aero helmets is what we went with.

PMK

Our tandem has been run in two TT events. One where my wife / stoker was on the back, and a second where friend that often rides the local series was on the back.

Both times the bike was run as it is on most rides.

Has anyone tried running a tubeless conversion for these short events? I know some in this topic are very critical of tire pressure and how the tire rolls. From that perspective, the more supple tire and casing may add benefit in reducing time.

We have done off-road time trials on a tandem. That was a lot of fun. Almost scary to realize how stupid fast you can go between trees when there is a need.

PK

Open Lateral

HED Cliplite aero bars. Kinda pricey, but light, and the best for us(me). I love them.
Go PMK!

merlinextraligh

Getting the aero position right on the tandem for both riders has its own set of challenges, if you're not going to have a tandem dedicated just for time trials, which I doub many people will do.

For the Captain, the problem is getting the position right using clipons. Ou tandem fits us well as a road bike, but conventional clip on bars raise my position too high, even with no spacers under the stem. Our answer to that was to use Oval concepts stem mounted under bars, and an Oval Concepts adjustable stem that allows a greater than -17% drop on the stem. The stem places the bars lower, and the under bar mount allows me to set up the pads so they're even with the top of the bars, so my forearms rest on both the handlebars and the pads.

merlinextraligh

For the stoker, unless you go with a custom built bike with a very long top tube for the stoker, the issue is getting the stoker low and tucked behind the captain in the limited amount of space.

We tried clip on aerobars for the stoker, and there just wasn't room to not have the bars hit the stokers knees or jam into the captain's legs.

Next approach was Cane Creek Speed bars. These are essentially drop bars, but moved in narrower. This worked reasonably well. it allowed a narrow, low position, tucked behind the Captain, but the downside compared to aerobars was it didn't give the stoker the same support and was a difficult position to hold for an hour.




Then my stoker discovered that she could low and narrow by resting her elbows on her handlebars and grabbing my seatpost. This allowed for a very aero position, where she is low, and close to my back (she can rest her head on the back of my seat in this position).
Downside was that it didn't provide a lot of support, was a bit unconfortable, and seemed a bit unstable.


Which led to the current evolution:



These are pads from a set of clip on aerobars mounted behind the stoker's bars, flush to the handlebars, utilizing a cutoff portion of the extensions from the clip ons.

Using this setup, the stoker rests her elbows/forearms on the pads, and stoker bar, and still grabs the captain's seatpost. She's just as low as without the pads, but has more a stable and comfortable position.

Only significant downside to the current setup is that she bumps her knees on the pads if we stand. However it's a 2 bolt operation to slide them off when not TT'ing.

Dean V

We went through a few combinations with the stoker bars too. Tried some modified aero bars with forarm rests. She likes the narrow low handlebar the best so far. Rides on it with straight arms and they are well shielded behind my legs. I also thought drag may be less with her hands out a bit. With them in narrow by the seat post I thought they might of caught more wind. Impossible to say for sure of course without a wind tunnel. We do have the luxury of a TT only bike also so I don't need to compromise on my bar height as you mentioned with clip ons on top of road bars. I normally have a 10cm saddle to bar drop with road bars but use a 14cm drop to my elbow pads on a TT bike.
I am going to build a TT frame soon with a 90cm rear top tube which will give her room to ride lower with a normal aero bar set up. I don't know if it will be faster but I think the only way I am going to find out is if I try it.

mrfish

Is it really worth trying to get the stoker lower?

I would imagine that as long as the stoker is not increasing the hole punched in the air by the captain (assuming the mostly female stokers are smaller) by having her arms sticking out around the captain, it's better to get her into as powerful a position as possible and as close to the captain as comfort allows.

Thoughts?

merlinextraligh

I hadn't really thought about frag from hands around the seatpost. Icould see that might have more drag than hands wider, hidden by my legs. Although the more I keep my knees in tight, the more her hands and forearms are covered.

Anecdotally, we're faster that way than a narrow low set up. Also, the pads is a more sustainable position for putting out power over an hour, given the support.

merlinextraligh

More than getting the stoker lower, I think is getting the stoker tight to the captain. Even if the Stoker is lower than the captain, there's going to be drag if air flows over the captain, and then into the chest of the stoker. There has to be less drag if air flows over the two riders as a unit.

Even though my stoker is shorter than I am, and is lower than my back when I'm in an aero position, when she's fairly upright, when she gets low and close to my back, we're at least .5mph from the same perceived effort. I'll grant that my .5mph is very unscientific, with lots of confounders, but you can definitely feel the difference.

waynesulak

I wonder if small cramped stoker compartments might be more aero as well. It seems with the shorter tandems the stoker ends up with their face in the captain's back rather than at the captain's rear end. It might make a more cohesive package.

Not great for general riding but might be worth it for a dedicated TT bike.

merlinextraligh

I think if you're going to purpose build a TT tandem, I think you want a longer stoker compartment, so the stoker can get flat.

waynesulak

That looks pretty streamlined. Looks like the stoker is holding the captain's seat post as well.

The Brits national team are renown for their big budget technical approach. I wonder if they have looked at tandems in a wind tunnel or just use a traditional track tandem approach.