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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 08-23-07, 03:38 AM   #1
mrfish
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What brake calipers?

I'm planning to fit new carbon forks to our Trek tandem this weekend (currenly on Avid cantis), and will borrow some Ultegra caliper brakes off another bike to get us going but will need to buy a front brake caliper soon.

Question is what caliper brakes offer the best performance on a tandem? I have read that the latest Dura Ace are more rigid than the old, but does it really make much difference? My experience on my single bikes is that the rim surface, wear-in to the brake pads and careful cable setup makes much more difference than the brake caliper. That said I find the Avids very marginal, so want the best braking I can get.

I will probably just go for either Ulegra or DA as the rest of the bike is Shimano unless there is a big performance improvement from say SRAM, Campg or something else. Another option could be the new beefier Zero-G brakes, but they're a bit expensive IMO.
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Old 08-23-07, 04:36 AM   #2
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My newest tandem came with the DA brake front and rear. I did put the zeros on and love them. The older model. I have heard of the new one but have not seen it yet. I am checking them out as a I write.

I am surprised you are not happy with the avids.

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Old 08-23-07, 09:20 AM   #3
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I can't decide whether I am happy with the avids. I though they were rubbish until I rode the tandem on my own. Then I realised that they are actually OK in comparison to my other brakes so perhaps calling them very marginal isn't fair. That said I've never managed to lock a wheel despite trying, so in my view they're not strong enough.

The brake and fork upgrade should solve these problems:

1) Adjusting the brakes was a pain compared to calipers as they patently aren't designed for use with STI levers. a) There is no cable adjustment so you have to set the lever pull by changing where the cable clamps. b) There is also no quick release mechanism and set properly the straddle cable is a real pig to undo - just about do-able in the workshop, but not something I'd like to tackle with cold hands in the rain as it's really tight. c) An hour of fiddling was required to get the pad angle / height / gap to rim / spring tension set properly.
2) Another minor issue is that the pads seem to like picking up grit / aluminium which will wear the rims faster
3) I can't get a low enough handlebar position. Despite having the same head tube length as my single bikes, the fork is so long and also requires a cable hanger below the stem that the stem is about 2cm higher than usual. You don't see this in geometry charts when buying the bike. You could solve it by buying a downwards sloping stem, but that's another cludge.
4) There is so much tyre clearance that when you do 20mph in the rain, water comes off the front tyre into the air then zooms backwards into your face.
5) Similarly the rear cable hanger on the is also a nasty afterthought and needs to go. A rear disc brake is planned.
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Old 09-01-07, 07:50 PM   #4
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Mrfish,

I am just about to do the same on my 2005 Trek T2000.

My thoughts are the DA calipers would be more than adequate for the job (over other brands out there). I have tried both Ultegra and DA ones on my single and I can just tell the difference between the 2, although I am a reasonably heavy rider weighing in at 220lbs, so I do give the brakes a good workout.

Out of interest what Carbon Tandem Fork did you get? (Tandemgeek has suggested the Reynolds one for us - and after looking at all the options I agree with his choice).

We upgraded the Avids to Shimano Tandem/Cyclocross V-brakes about 1 month after getting the bike and noticed a huge difference, but I still find the rear brake really "soft". Unfortunaly no way of putting calipers on the rear as the 2005 frame is not designed for them. I got an Avid BB-7 Road put on as a 3rd rear brake (instead of a Drum) - but after about 8 months, I think I am going to get rid of it. In this time, we have only had to seriously use it 3 times and it causes me more grief than it is worth. On those occasions I have had to use it, have been long windy descents, I could have stopped a few times to give my hands a break instead.

If anyone has any suggestions on the rear brake "issue", I am open to try anything.

Last edited by thebearnz; 09-01-07 at 08:30 PM.
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Old 09-02-07, 11:21 AM   #5
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I'm using Ultegra front dual pivots with Reynolds Ouzo Pro fork, and Tektro extra-long-reach rear dual pivots on my steel tandem. The 2-pivots work way better than any v-brakes with compensators I have used. I once lost just about all braking in the rain when using the v-brakes (very rapid pad wear in the rain, and the pads are too thin to start with).

But all of my single-bike experience has been on the road, and I am far more comfortable with road equipment. I am very impressed with the design and aesthetics of Campag's 2-pivot calipers; they look as if they would provide more leverage. I'm using Centaurs (with Tektro Campag-style levers) on my fixed-gear winter bike and am very happy with them, but the front Ultegra has been working remarkably well in stopping the tandem (about 320-lb crew weight).

The rear brakes still don't feel very effective (but better than v-brakes w/compensators anyway); maybe discs are the way to go here.

- L.
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Old 09-03-07, 04:11 AM   #6
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Thanks for the comments. I still haven't fitted the fork yet as I managed to find a front DA slightly used brake on ebay for pennies, so I'm waiting until that arrives. Also the local cane creek distributor hasn't yet answered the phone, so I'm still looking for a spare fork race so I don't need to remove the one on the stock forks and can swap them back if we somehow get the urge to go tandem touring.

I have a True Temper X2 tandem fork, mainly because it was lower and cheaper than the others. Disadvantage is that I won't be able to use big tyres, but that's not a problem as I plan to swap to 25mms when the stock Bontragers wear our. An added bonus should be that the steering speeds up a bit, but not a big deal IMO. I will report back once it's running.

To improve the rear brake, I made a reasonable improvement by tweaking the cable set up. I've given up further tweaks like Nokon cables and new pads as I think the best solution is to use the BB7 as a primary brake, which is what is what I'm planning when time allows. I am surprised though that you don't like your BB7. Others have had good results - have you tried using it as your primary rear brake? If you've only used it 3 times, it may not have bedded in yet. Also try Tandemgeek's extra spring in the operating arm, which ensures the pads retract properly.
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Old 09-03-07, 06:15 AM   #7
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Thanks for the update MrFish

Actually we have used the BB7 semi regularly (when the captain - me - is feeling lazy). Maybe it is the way we have it setup - brake lever on the stokers handlebar, full length cable housing along top tube and down right seat stay. Held on with cable ties.

Our biggest problem is the brake does not always fully release and creates extra "drag" that we don't need

I am fairly certain this is due to the cabling, but no one has any suggestion on a better way to cable this. A number of bike mechanics (who all ride tandems) have strongly suggested to get rid of it.

An option I have looked into might be a Winzip mechanical disk, where both pads actuate (like a Hydraulic brake). However I am hesitant to spend more unless I can get a good solution. Maybe a caliper on the rear might work just as well if I can work out how to mount it.

End of the day, both current rear brakes are only just slightly better than dead weight (except on the 3 occasions where life would have been difficult without the BB7 helping to keep our speed down to a tad over 30kmh on some long windy decents - even then it was a little fast for my liking).
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Old 09-03-07, 06:42 AM   #8
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IT's a kludge, but ow about a second return spring to assist? You could put a spring captive around the cable that will push the lever to the fully open position.

Sheldon
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Old 09-03-07, 06:55 AM   #9
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Your problem with the BB7 is easily fixed - Tandemgeek recommends putting a spring in between the BB7 actuation arm and the BB7 body. This pushes the pads back properly and avoids drag. There was a thread with pictures a couple of weeks back. Just search on TG's posts and say BB7 and you'll find it.

On the cabling setup, the top tube routing is OK, but I'm not so keen on zip ties down the seat stay. I think there is a cable stop on the bottom of the downtube, then bb cable guides seem to have room for a central cable, so you may be able to route the cable in the same way as the rear derailleur, which would have the advantage of needing less cable outer, giving better performance.

Probably the hitch is that there's no cable stop on the chainstay, but I'm sure you could bolt some sort of cable stop onto a threaded hole tapped into the inside or outside of the Arai reaction arm connector if you don't plan to use it. That would certainly look neater (and void warranty etc...). I will have a look when I get home.
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Old 09-03-07, 07:04 AM   #10
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Disc Brake Drag
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Old 09-03-07, 08:14 AM   #11
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Quote:
Originally Posted by thebearnz View Post
If anyone has any suggestions on the rear brake "issue", I am open to try anything.
A couple questions:

1. What size rotor is fitted to the rear disc?
2. What types of problems are you having aside from the poor pad release?
3. What were you hoping to achieve by changing from the Arai drum drag brake to a disc drag brake?
4. Can you post a photo of the left rear portion of your tandem?
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Old 09-03-07, 03:59 PM   #12
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Quote:
Originally Posted by TandemGeek View Post
A couple questions:

1. What size rotor is fitted to the rear disc?
2. What types of problems are you having aside from the poor pad release?
3. What were you hoping to achieve by changing from the Arai drum drag brake to a disc drag brake?
4. Can you post a photo of the left rear portion of your tandem?
1. I think it is a 160mm that comes standard with the BB7 Road, discussions are we could take it up to a 180 (203 gets a little close to the stays).

2. Mainly poor pad release, as such I tend to run it with a wider gap between the pads and rotor to offset the return issue, which makes it "soft".

3. Never had a Drum brake. Only put this 3rd brake on becuase the rear V-brake is too soft and near useless. Upgrading from the Avids to the Shimano V's made a huge difference up front, but almost nothing in the rear. Where we ride 99.9% of the time I do not need a 3rd brake (disk or drum). However becuase the disk is easier on the hands, I sometimes get my stoker to use it near the bottom of a hill before I put the main brakes on.

4. Will post a photo when I get home tonight -

Note: we do not have the Bontrager wheels. Long story - but I am going to give it to yah anyway, becuase it might help explain the situation.

The wheel thing has been a huge learning experience (and I don't trust all bike shop owners now!!), Brought the T2000 near new from a bike shop. Owner had his CD crack in the frame and decided to try a Trek out. CD replaced his frame and he decided to go back to riding the CD but kept the Bontrager wheels. As such I got a great deal on the bike (less than 1/2 price for something that had done about 100 miles). If I had known back then what I know now, I would have forked out for a set of Bontrager wheels the next day.


So the guy had built up a set of wheels with Mavic A319 rims and XT hubs (with a 135 rear axle!!! I wondered why I had so many problems with my rear wheel.) Because the original bike shop was about 150kms away, I took it to my local (who is also a fellow tandemer) and he would not let me take it out of the shop until he had replaced the 135 rear axle with a 145 one (for safety reasons). And that was the start of my fun with these wheels. So far I have had these rebuilt with stronger spokes and the disk brake setup is even more b@st@rdised at the moment as spacers had to be put in to get the rotor in the right place (because the XT hubs are designed for a 135 rear spacing).

Bontrager Tandem wheelset upgrade is planned to happen in about 2 months time when our summer cycling season kicks in.

Seperate to this, I am still yet to be happy with my rear brake (or maybe it is just becuase I ride my single as often as the tandem and expect the brakes to be just as reactive?)

Last edited by thebearnz; 09-04-07 at 12:16 AM.
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Old 09-04-07, 06:45 PM   #13
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Here are the photos
Attached Images
File Type: jpg Tandem Left1.jpg (97.7 KB, 39 views)
File Type: jpg tandem left 2.jpg (98.1 KB, 39 views)
File Type: jpg Tandem_Rear.jpg (82.3 KB, 30 views)

Last edited by thebearnz; 09-04-07 at 07:05 PM.
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Old 09-04-07, 08:21 PM   #14
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Given all the upgrades you're considering, my recommendation would be to consider a complete tandem upgrade to the second generation T2000. Seriously, with various upgrades that you're mulling over -- $550 for a Bontrager wheelset, $550 for a carbon fork, and brake changes yet to be defined for another $100 - $200 -- and the residual value of your current Trek tandem, you're within a few hundred dollars of a NOS '06 Trek T2000 that comes standard with all the parts you're after (but you'd still want to add a compression spring to the Avid). Moreover, when Trek redesigned the T1000 / T2000 framesets back in '06 they fitted a proper I.S. disc mount and curved rear stays to accomodate a 203mm rear disc along with a drilled rear brake bridge for a rear caliper. Just something to consider. I found myself at a similar crossroad only about 7 months when I realized that no matter how many components I changed on our first tandem, it was the limitations of the frame that I was struggling with. I fixed those things with a new tandem frame that -- 10 years later -- is still a joy to ride.

OK, now that I've got that off my chest...

1. As much as I don't like them, to really beef up your rear brake power you might consider going to a Shimano LX V-brake with a Problem-Solver 'Travel Agent' or Sidetrak 'Brake Pull Booster (BPB)': probably about $50 all told. The LX is suggested as a way to minimize the potential for brake squeal that sometimes comes from the brake pad alignment linkage on the XT models and, well, they're very strong and very inexpensive. That would give you the most amount of rear brake power that you can get with a rim brake.

2. You can probably "fix" your stoker controlled drag brake to work "better" with the compression spring that MrFish mentioned and provided a link to and by making sure that the spring tension screw is set to it's highest tension. I'd also investigate your cable routing to make sure that it's as smooth as it can be. Running full-length cable housing isn't awful, in and of itself, but the glue-on / zip-tie on cable guides are a better choice.

3. The "ultimate" hybrid system is probably counter-intuitive, whereby you'd go ahead and upgrade the rear brake to the LX V-brake but, instead of controlling it with your STI brake lever, you'd make it the supplemental brake to be controlled by your stoker via her hand lever. The V-brake works here because it doesn't need a cable-stop, per se, as it's integrated into the travel agent and/or the V-brake noodle and will only need one or two cable guides on the top tube for the cable housing. Now, as for your rear brake, you have two choices:
a. Stick with the 160mm rotor and run two standard length brake cables joined using a brake cable splitter all the way to the rear disc caliper. You'd run the housing from the existing rear brake cable stop down to the rotor with one or two stick / zip-tie on cable guides. You'd also want to run the Avid's spring tension screw all the way in and add the aformentioned compression spring to improve the brake caliper's performance and feel.

b. Do everything in a., above, but if it will fit inside the stays drop a few more bucks into the rear disc to make it "better" by upgrading to the 180mm rotor ($$ for the rotor and a new Avid adapter). It still won't have the stopping power or heat capacity of the 203mm rotors -- which is the only size rotor that Avid has ever endorsed for use on a tandem as a full-time brake -- but it will be better than the 160mm rotor.
That's really about it. The "best" set-up for your '05 would have probably been an Arai drum brake mated to a really good cantilever or V-brake. But, again, having gone through the addictive bike upgrade process a few times -- usually consuming more time & re$ource$ than a factory-fresh machine would have -- I'd spend some time with pen/paper/calculator or an Excel spreadsheet running the numbers on your potential upgrade expenses before heading down that path.

A 'first tandem' is just that... the tandem you own and ride while you learn more about tandems and come to find out if it will be your only tandem or if you'll apply the lessons learned with that tandem to your next tandem.
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Old 09-04-07, 09:30 PM   #15
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Thanks Tandemgeek - I have to admit the complete upgrade has crossed our minds more than once. The new 07/08 T2000 looks to be a beaut of a machine, but I have also been looking at Co-motion and Santana choices and S&S coupling (darn it is hard).

The biggest problem I have is there are no tandem shops in New Zealand, all tandems are by special order only - so there is no chance to try anything out. Considering we would be spending between $7000 (new Trek T2000) - $13,000 (Carbon or Titanium tandem with maybe S&S couplers) NZ dollars to upgrade, it is a fair whack to pick something based on Specs off a website.

We are thinking about a trip up to the US sometime next year with tandem shopping on the agenda.

Ok, sounds like I am going to keep the money in the bank for the big upgrade next year

The current setup rides ok, I just have be more cautious when in pacelines or longer downhills. Worst comes to worst, if the Avid annoys me enough, it will come off for a while and I will fiddle with the rear brake a bit more.

As mentioned above the front brake works fine (except the hand gets a little sore if I am on a windy bit of downhill)

Last edited by thebearnz; 09-04-07 at 09:47 PM.
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