ahultin

So I got the RT2 out for a quick 20 minute ride this evening. Road it for about 5 minutes solo then about 15 minutes with my 12 yr old. Our intention was to get a good 20 mile maiden voyage in but we lost light to early. In this short ride I made many observations.

1. Steering is substantially different then my single and felt slower
2. Reading the "proper method" is very helpful
2. New brakes suck! Okay to be fair, when I got back in the house I found that the bb7's where very poorly adjusted. I read the park guide for adjusting them and think I got them pretty close. Will have to try them tomorrow
3. Contrary to my expectation climbing seemed easier with the extra helper on the back.

Some bike issues I noticed

The stoker bars hit my thighs when pedaling which I figured no problem I would adjust the stoker stem, um wtf, why do they spec an adjustable stem with all of 1/2 in of adjustment?? Control tech 255mm adj on order. Flipped the bar for now

Although I transferred my singles measurements I felt for lack of a better description, too close to the front wheel. On my single when I look down the fork the bar obscures the center of the hub. On the tandem when I do the same the bar seems ahead of the center line of the hub. I would like to move the seat back some but the location of the eccentric is @3pm when looking from drive side. If I move the seat back more I will be further behind the BB. Should I/Could I spin the eccentric around to @9pm and pull a link?

The cables up front seem to have excess length (as compared to the single) is there a purpose for this or can I shorten/clean up


Thats it for now
Thank you for any advise

Tom Spohn

We also have an RT2. The stoker stem is notoriously short on the larger frames. A call to Mel at Tandems East will get you a perfect replacement that has a much larger range extension. On our bike the bars were too narrow for me so the dealer swapped out wider bars and a different stem. Regarding your seating position you may need a longer stem to keep your knees in the proper pedaling position. Drop a plumb line from the front of your knee and it should just touch the end of the crank arm. If it doesn't do this you can slide the seat or replace the stem or both till you dial in the proper position. Yes, I know this is just for initial adjustment, but it will be pretty close. Don't get too upset yet. This is a great bike and it sounds like your problems are just fit and adjustment.

What size is your bike? What size are you?

Mr. Beanz

You have your stoker's handlebars in a strange position.

ahultin

I had to flip them to that position due to the fact that "the right way" they where hitting my thighs. The adjustable stem on this is a joke (max 1/2" of adjustment) so I couldn't move it back any. I have ordered the control tech adjustable which should give considerably more options.

Mr. Beanz

I wasn't sure it it was the fact that Seb couldn't reach the bars. Either way, It seems that the handle bars on Ron And Dixie's tandem (red jersey) are very wide compared to ours. Might be another option, wider bars.

Not to mention that another couple we met with a tandem like yours has the drop bars, another option. They seem to be out of the way of the captain's way.

ahultin

Yup, Stoker stem needs to be different! I have ordered the control tech adj stoker stem with the 215-255mm range which should help. The Captain bar width matches my single at 44cm. I am not sure what the width is on the stoker bars.

I do think I need to move the seat back (in lieu of a longer captain stem) but am concerned that with the eccentric where it is i will be to far behind pedal center. Is it reasonable to roll the eccentric and remove a link?

Bike is an X/S
I am 5'11" but with monkey arms that give me a 6'4" reach

Dean V

I think the normal stoker bull horns are around 46cm centre to centre. Certainly wide enough to clear a lot of captains but obviously not all. You will not have enough adjustment in that eccentric to take 2 links out of the timing chain. You will probably need a 130 or 140mm stem if you have a long torso/arms also. Ignore the seeing the front hub idea for setting it up. Put your saddle at the height and set back from the bottom bracket that you normally have and the set the distance to bars from saddle, and seat to handlebar drop from there.

twocicle

1. If you setup your captain saddle position over the BB correctly (or otherwise mirrored a known position from another bike ie: single), then you should not move the saddle back just because of a reach issue. Also, you are a tall guy on a small frame. Best to leave the eccentric in the forward position so you do not needlessly encroach on the stoker area.

Instead, your eccentric appears to be in 2pm position so rotate it to 4pm and lower your saddle position accordingly (has added benefit of lowering your COG and improve stability). Then, flip your stem so its angle is down instead of rising as it appears to be in the photo... this will have the effect of lengthening your reach maybe .5cm and you may not feel the need to move your saddle back. If you still need more reach, try a longer stem. Add/remove stem spacers to achieve your proper bar-to-saddle drop differential... and by the way, on a tandem it is typical to use slightly less (I'm talking about <= 5mm) of a drop than on a single.

2. Do not move the stoker bars to satsify your (captain) setup needs. Setup the stoker area to properly accommodate the stoker's preference and/or needs. Obviously if the stoker bars rub the captain's butt/thighs/etc, then something should be done... like using wider bars for example. Using wider stoker bars on a tandem is a typical adjustment and 4-6cm wider than a single bar setup is not uncommon.

Bill G

Nice Canondale, it looks great,

Some of the issues you mentioned is why I build my own tandems. I have them dilivered unasembled from Co Motion & da Vinci but with the Canondale that is not an option. When we purchased the Cannondale we use to own I disasembled it down to the bare frame and built it back up correcting all the issues such as cables being to long and adjusted everything to spec includeing all our documented fit specs/measurements for proper fit.

You mentioned moving your seat back to get fit correct. I suggest to you before you do that check top tube length between your single bike and your tandem (I bet the tandem is longer) and make sure your knee to peddle spindle measurement is correct. If your still to stretched out more than likely your top tube is longer on the tandem than your single and you will need a shorter stem on the tandem to get things correct. This is the proper way to adjust your reach instead of moving the saddle back or forward. Always set saddle height and knee geometry to peddle spindle first (with plum bob as mention above) before adjusting reach to bars and do not use moving the saddle back and forth for this adjustment. Always adjust the reach to bars with the length of stem used to get your reach to the bars right. (the rule of thumb is the bars should block out the front axle or hub when riding on the hoods if you glance down)

You mentioned the stoker bars hitting your hips that is why me and the wife swithed to the set up below to solve the issues that are commen with regular 44cm/46cm bull horn stoker bars that come on tandems new.

(NOTE COPY OF POST BELLOW) sent in another thread explaining the stoker bar configuration we changed to to solve the issue your having with your hips hitting the stoker bar.

The stoker bar is a 50 mm rise x 29.5" 31.8 clamp mountain bike downhill bar ( the exact bar is is a Funn Fatboy bar cost $44.00 the grips are Ergon GS3 leichtbau composite size small $54.00) both purched at Universal Cycles online.

The bars have bean cut down to 22" or 55.8 mm wide ( would not recommend cuting shorter) I cut 3.75" of each end with a tubeing cutter (nice clean cut). They look really short after you cut them but as you can see on the tandem they turn out just fine and are wider than the captains bars leaving plenty of room still for your hips. I have run this type of bar with diffrent grip styles on all our tadems my wife and stoker loves them. Any brand moutain bike riser bar will do the job just pick the amout of rise you want 30 mm, 40 mm, 50 mm some times they say 1", 1 1/2" or 2" rise have even seen 3" rise offered. I like them better than any of the 44 mm or 46 mm wide stoker bull horn design bars that come on tandems myself. The moutain bike riser bar cut down is wider and more comfy for the stoker.

See Pic's below of our Co Motions we have owned & our new da Vinci Joint Venture with the stoker bar changed to a cut down flat bar set up. The Co Motions are cut down to 22" or 55.8 mm but with a 40 mm 1 1/2" rise instead of the 50 mm 2" rise like on the da Vinci. I put a 50 mm or 2" on the da Vinci because they worked out better with the type of stoker stem that's on the da Vinci to get the stokers fit where she likes it..

Ride Safe ,
Bill G

Carbonfiberboy 

Wider stoker bars. With her hands on the forward part of the bars, her fingers should still clear your thighs/butt.

Set the stoker stem and stoker bar height to what is comfortable for stoker. Make it as much as possible like her single.

New discs or pads do suck. It will take them a little while to bed in. Meanwhile, give yourself a little extra distance. You can speed the process by riding hills and stopping at the bottom.

And what twocicle said.

Tom Spohn

Our RT2 is a L/S so not too different from yours. The stoker bars are 46cm center to center and the captain's are 44cm. The longer stem solved any problems we might have had with with stoker bar contacting captain. My suggestion would be:
1. Leave the eccentric alone. First set up the proper position for your knees to pedals. Either use the plumb line method or, better yet, carefully measure your single bike and transfer the measures to the tandem.
2. After getting (1) right then transfer the measured relationship of bars to saddle from your single to the tandem. You may need to replace stem or add or subtract spacers, stem rise etc. On ours we were lucky that it came out right the first time.

Although not a fit issue we had the LBS put Specialized bar fat under the tape on the bars and like the shock absorbtion it provides. Stock Gatorskins were OK, but we really like the GP4X better. Good luck on a great Bike!

twocicle

^^^ leaving the eccentric in the upper half of the rotation almost never makes any sense. The 2pm position is usually not ideal unless you have some special case which is?

Dean V

Only reason I can think of is when using different forks which lower the front end (this is the situation with our bike). You then may need the front bb in the upper half to get a better bb height from the ground.

ahultin

Measured the tt of both and the tandem is 56.5 vs the single at 57. I then rechecked seat position in relationship to the bb. The seat on the single was 2.5cm further back so i moved the seat back as far as i thought safe which got them within. 5cm. The reach is pretty close now between the two. The seat to bar drop is is off by 1.5cm so ill pull one of the spacers tomorrow and see how it feels.

waynesulak

Those teams that have a stoker about the same size or even taller than the captain have problems getting the stoker bars high enough. Placing the eccentric in the top half raises the captain's seat post head and allows for just a little more height the the stoker stem/captain seat post interface.

Bill G

The key thing here is get your knee position correct by dropping a plum bob from just under knee cap to peddle spindle at the 3 o clock position the plum bob line should fall center of peddle spindle or slightly behind center a few mm with your but in the proper rideing position on your saddle, I like behind a few mm myself (look on the web for pictures & procedure or the Link below of how to exactly do this correctly and where to put string under knee cap in relation to peddle spindle) When this has been done correctly first then you adjust the stem shorter or longer more or less spacers, what ever is needed here to get your reach right.(NOTE) If you are only adjusting the saddle forward or back without the knee geometry to peddle spindle being right first everything will be wrong..

Link below to a good bike fit procedure...The colorado Cyclist link to bike fit below is real good and explains everything well

https://www.coloradocyclist.com/bikefit/#kneeposition

https://www.jimlangley.net/crank/bikefit.html

Ride Safe,
Bill G

Looigi

FWIW: Lower is not more stable. It's kind of like balancing a pole on the palm of your hand. Taller is easier to balance than shorter because a tall pole falls over more slowly than a short pole. This effect is quite noticeable when learning to ride a low-slung recumbent.

twocicle

Wrong. There is no way you can justify the arguement that a higher COG is more stable in cornering. Frame design material is a good place to start your research as it discusses BB height variations and effects. Lower BBs (a larger drop from the line between front and rear wheel axles) creates a more stable ride typically used for general road riding, higher BBs are used for track, criterium and mtn bikes where banking/cornering pedal clearance is prime. Apply that knowledge to the effective BB height variances created by an eccentric.

Out of curiosity of search hits, simply using: "bottom bracket height stability" discusses this topic.

Dean V

I can verify that a low recumbent is more difficult to ride and balance than a taller one. A tall unicycle is also easier to ride than a short one ,it just hurts more when you do fall off.

twocicle

^^^ Seems pretty much irrelevant to this thread topic and the gist of COG/BB height preference on upright tandems. Perhaps it would be better to discuss falling over on recumbents in another thread.

ahultin

Thank you, i should have clarified, i had a full bike fit on the single about a year ago( 3-4 hours of measure adjust measure adjust) and find it comfortable so i am trying to duplicate the measurements from the single onto the tandem. One big difference is that the single has a setback seatpost so all said and done the bb to seat setback is still off about 5mm but as close as it will get without a different seatpost (which will infringe in stoker space)
Got home late this evening so i did not have an opportunity to lower the stem and test it out but plan on doing it tuesday.

twocicle

Sadly, it is not always possible to stay with the exact same make and model components for capt and stoker. As you probably already determined, the Thomson setback post would interfer with the current position of the stoker stem clamp on your capt seatpost.

Another option, same result... you could achieve a wider range of fore/aft positioning using a saddle with longer rails (ie: up to 85mm are available). The Fizik Aliante which appears to be the saddle on your RT2 probably has shorter rails (the usable flat section) than the Arione for example of another in the Fizik line.

cplager

You are the one that said

And they called you out on it. They never mentioned bottom bracket height, you did. And they provided examples of how you were wrong.

So, this seems as on topic as your replies to me. Would it have made you happier if they said low recumbent tandems are more difficult to ride than a taller tandem?

Charles

PMK

Pretty much the ideas posted are valid. As mentioned, I would prefer to see a good fit of seat height, seat fore aft relative to the bb and then dial in stem length.

As for where you place the eccentric, fore vs aft, above vs below center, this all is a matter of you and your stoker as a combined fit on the bicycle.

Aim for, but don't get too wrapped around the idea of an exact same fit as your single bike. For us this doesn't always work. The tandem rides different, often does not see the riders stand as often, and for the captain requires different amounts of strength vs the single to maintain control.

My recommendation, as much as you are worried about your fit, get the back seat perfect first. If not you WILL need every bit of efficiency to go fast as your stoker becomes uncomfortable.

Get the stoker the best fit for long term seated pedaling at her cadence. Suffer a few rides to ensure this. THEN, knowing the exact parameters of the stoker, start working on fit for the captain. Obviously, get the seat height and fore aft dialed in first. If this means moving the eccentric do it. Work the bars position as a final chapter.

In regards to stability, CG, and so forth related to the eccentric, these all relate to control, but a good fit easily knocks eccentric position to a distant second. If you need a reason to run above center, tell other teams it is for better clearance when hammering corners leaned over and pedaling.

FWIW, my so called stumpy legs on my 5'10" body and a 5'6" stoker have had the eccentric on all our tandems, both past and current run the eccentric above center and forward.

Be patient and best of luck with it. I would be very surprised if your best overall fit for captain and stoker was exactly as it would be on a single bike.

BTW, regarding the brakes, make certain they are properly aligned and the discs have been cleaned with solvent, then with a reasonably weighted rear seat, burn the brakes in with some serious hard stops. Your complaint is typical. They should get much better.

In regards to the cables and other oem fit of stuff. Remember the bike is a production machine and not custom built and assembled. Get all your fits and such dialed, then have the shop build it right in your eyes. Shortening new cable housings are easy and inexpensive. Regarding the brakes it will also make them more solid at the lever.

PK

Bill G

PMK you are 100% right with everything you said. Get saddle height and peddle to spindle fit right first then dile in the handlebars and reach and it is not possible all he time to match bike to bike perfect. Also your right about tandems being diffrent even my tandems differ a little between each other due to each manufactures diffrences in build geometry.. That is why it is so important to fit each bike by it self and follow a good fit procedure step by step on each cycle based on its own specific geometry and your body.

The fit procedure I sent on a link above from Colorado Cyclist is a good one for example and I think the original poster should start from scratch and get it right based on his tandems specific geometry and not try so much to copy his single bike. I think he will be happier and get a better result this way.

NOTE not to offend here but that is what I have been trying to say to him but he keeps coming back and saying he is going to keep moving that saddle around to get things right trying so hard to copy his single bikes measuements exactly to a tee and maybe not realizing the seat tube angles and geometry of his tandem is more than likely way diffrent than his single. All this plays a big part into proper bike fit, more than most guys even realize.

That is why they have these fit procedures and if you follow them on each bike specific to each bikes specific geometry you can get pretty much the same fit bike to bike if done right and have your body fit right even though the specific measurements from bike to bike may differ.

Ride Safe All,
Bill G