# 160 or 203 brake disc choice for tandem



## [email protected] (Dec 2, 2006)

Would a 160mm disc be sufficient on a tandem riding over hilly roads where the descent may last several miles over fairly steep gradient or would I need a 203mm disc? No, it would not as agressive as DH.

Thanks.


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## sparrow (Dec 30, 2003)

*Get the 203mm front*

Get the big front rotor (all other things equal), a bit more power, better to handle more heat, etc. Front brakes are even more critical on an offroad tandem than on a single.

We run Magura Gustav with a 210mm front and 160mm rear, works great. The Gustav is alot like a motorcycle set up, alot of fluid volume, and big big pad contact area.

What brakes are you considering, and what bike? Check www.mtbtandems.com for abit more offroad tandem info.


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## dogonfr (Jan 6, 2005)

I would agree go 203 on the front. :cornut:


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## crisillo (Jul 3, 2004)

203 all the way :thumbsup: maybe a 180 in the rear ... not that big weight difference...


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## anirban (Apr 20, 2006)

Having a 160mm on the front would result in fading... very bad!! For a tandem, 203 is a safe bet. I would also recommend having at least a 180 in the rear, might help in modulation.


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## befoot (Mar 11, 2006)

Ok, I'm looking at 203's up front and 185's out back.
I have had very good luck with Avid BB7's on my short bikes or should I go with Hydraulic brakes. thinking again with Avid's Juicy 7's or Code 5's brakes...any thoughts? Thanks
(I'm on a tight budget...but we do like to stop)


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## dogonfr (Jan 6, 2005)

befoot said:


> Ok, I'm looking at 203's up front and 185's out back.
> I have had very good luck with Avid BB7's on my short bikes or should I go with Hydraulic brakes. thinking again with Avid's Juicy 7's or Code 5's brakes...any thoughts? Thanks
> (I'm on a tight budget...but we do like to stop)


Why not start your own post instead of digging up an old one???

If your on a budget go with the BB7's.


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## sparrow (Dec 30, 2003)

BB7s with 203 up front, I second that motion. You gotta remember to adjust the pads from time to time to account for wear.


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## damion (Jun 27, 2003)

*Hydro all the way.*

If I were setting up a tandem for the flats, I would still get a huydo setup with a 203 up front. (on a tandem, no such thing as flat)

If you already have parts, or are on a budget, that is one thing, but I save in other areas to be sure I have 1 finger braking. I would insist on the same feeling for a tandem.

I have seen photos of a andem with a disc and a v on each wheel, with 2 levers mounted at each hand. (now that is power)


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## TandemNut (Mar 12, 2004)

You can use the BB7's with no problem, as long as you size them at 203mm front AND rear (Avid's requirement for tandem use). You can also upsize them with Haye's 9" rotor kit. 
As for everyday useable power and simplicity, the Avid's are hard to beat. The BB7 is also the only brake Avid approves for tandem use, period. 
Magura Gustavs have more brute stopping force, and probably more ultimate heat resistance. Magura Louise Tandems are definitely lighter, just as powerful, and modulate better. 
But BB7's are very hard to beat for the money.


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## befoot (Mar 11, 2006)

Hi all, Thanks for the info.


> The BB7 is also the only brake Avid approves for tandem use, period.


 thanks Alex, I was thinking the DH Hydraulic stuff would be better. good to know.



> Why not start your own post instead of digging up an old one???


 dogonfr...I like to use the search engine and it's works good when all the info is in one place like for braking. and not in a lot of little threads.(my thinking anyway...correct me if I wrong)

Cheers everyone.


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## TandemNut (Mar 12, 2004)

befoot said:


> Hi all, Thanks for the info.
> thanks Alex, I was thinking the DH Hydraulic stuff would be better. good to know.


Much of the tandem rating comes from failure mode, not just braking strength. If a brake can generate the appropriate stopping power, and dissipate the resulting heat from that power, (which are two different things) then the brake is a candidate for tandem use. However, how the brake may fail is also an issue; Chris Timm had an experience where he melted the line off a rear 160mm Gustav brake. That's a catastrophic failure mode, since one permanently loses the brake at that point, and wouldn't be considered a good option. Magura's response was to upsize the rotor for tandem applications to a 190mm rear minimum. Seems to have worked. 
If a brake overheats and locks up, that's a less catastrophic failure mode, and preferable to a line melting off or other structural failure of the brake. The brake can be recovered, and hopefully the locking wheel also serves to keep the bike from continuing forward. Now before someone lectures me that a locked wheel is not a good control situation, I only say that in comparison to losing the brake line and the brake completely, it is preferable. 
The Avid BB7's tandem rating appears to result from real-world experience of using the brakes on tandems over the years without documented failures. Many tandem builders adopted the brake early on, and they have been used for touring tandems for years. We got the official OK from Avid a few years ago. The failure mode of the mechanical brake would be, ultmately, the melting of the adjusting knob and the frying of the grease in the brake, as well as the brake no longer stopping the wheel. Both of those are likely recoverable failures, assuming one doesn't ride off an Alp while this is going on.
Avid, Hayes, and Shi*mano don't do any tandem-specific testing of their brakes, and their engineers don't feel the brakes are overbuilt enough to be up to such use. Hope is fully okay with tandem use of M6 and the new Moto (which I haven't tried yet).


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## Spongebob (Dec 30, 2003)

*IF* your frame accepts them, go with the 203's. I bought a road tandem with 160mm BB7s last October. We have a heavy team at 400lbs. Surprisingly, the biggest I could get on the frame and fork were 185's. Generally, tandem riders recommend against hydraulics b/c of the heat issue, from what I've read over at Bikeforums/Tandems. http://bikeforums.net/forumdisplay.php?f=44 Of the BB7's, the only talk is of melting knobs, on severe downhills. And be sure that the fork is rated for the larger rotor, if you can actually have the manufacturer admit that. Have fun!


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## befoot (Mar 11, 2006)

thank you 
you guys are awesome....so next Question would be,
John from Double_Forte gave us a very good deal on a Headshok moto FR fork...and we just got a Killer deal on a "NEW" 2001 Cannondale MT800 frame. (L/S our size this time...sorry Alex I was saving for a Fandango, next time for sure ) anyone know if the 203's will fit this set up? Cannondale didn't list rotor size in their catalogs.

thanks,
Billy


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## patineto (Oct 28, 2005)

I read somewhere that Hayes is making a 220mm rotor, I think is distributed or made for Santana or something...

Well by now you know my choice so I don't even go there.


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## crisillo (Jul 3, 2004)

patineto said:


> I read somewhere that Hayes is making a 220mm rotor, I think is distributed or made for Santana or something...
> 
> Well by now you know my choice so I don't even go there.


formula also has a 220mm rotor...


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## patineto (Oct 28, 2005)

crisillo said:


> formula also has a 220mm rotor...


Sorry maybe is Formula, this days I'm a total space cadet..

No matter what the bigger the better in terms of of expose area & heat dissipation.


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## crisillo (Jul 3, 2004)

patineto said:


> Sorry maybe is Formula, this days I'm a total space cadet..
> 
> No matter what the bigger the better in terms of of expose area & heat dissipation.


no, you were right....well we both are...

both Formula AND Hayes make 220mm rotors


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## patineto (Oct 28, 2005)

crisillo said:


> no, you were right....well we both are...
> 
> both Formula AND Hayes make 220mm rotors


Oh great I'm not going senile, at least not today..

personally I love the Hope floating rotors with the aluminum carriers, far less drag, lighter and also dissipate heat super fast, mandatory on a tandem for sure.


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## TandemNut (Mar 12, 2004)

We've got some of the Hayes 220mm rotors here. In fact, there's a post on this very forum with a picture of them, for those who are interested.
Hayes, BTW, is adamant about their brakes not being tandem-rated. The 220 rotors are also not tandem-rated, according to my rep. Now how a rotor of the same material and thickness as a smaller 203mm rotor that is tandem rated can't be tandem rated is a little beyond me. Too many lawyers!


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## TandemNut (Mar 12, 2004)

befoot said:


> thank you
> you guys are awesome....so next Question would be,
> John from Double_Forte gave us a very good deal on a Headshok moto FR fork...and we just got a Killer deal on a "NEW" 2001 Cannondale MT800 frame. (L/S our size this time...sorry Alex I was saving for a Fandango, next time for sure ) anyone know if the 203's will fit this set up? Cannondale didn't list rotor size in their catalogs.
> 
> ...


Make sure the fork is the Tandem version of the FR; very important if you're running disc brakes. There's a thread in the DF archives that describes how to tell (memory fails me on this), but I do remember that C'dale had some failures of Moto FR forks on tandems when used with disc brakes, until they upgraded the fork legs. Might be worth checking out.
Otherwise, we've run 210mm rotors on the forks before.


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## Speedub.Nate (Dec 31, 2003)

befoot said:


> thank you
> you guys are awesome....so next Question would be,
> John from Double_Forte gave us a very good deal on a Headshok moto FR fork...and we just got a Killer deal on a "NEW" 2001 Cannondale MT800 frame. (L/S our size this time...sorry Alex I was saving for a Fandango, next time for sure ) anyone know if the 203's will fit this set up? Cannondale didn't list rotor size in their catalogs.
> 
> ...


Noting Alex's cautions about the mounts, the 220mm rotor definitely fits the rear. The edge of the rotor lines up approximately with the rear edge of the drum brake tab mounted on the chainstay, and it's got maybe 4-5mm of lateral clearance from the chainstay. 203's, obviously, won't be a fit issue.


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## patineto (Oct 28, 2005)

Speedub.Nate said:


>


Yeah for sure they are not going to heat up, specially with such a big tire to take the cushion...

Were have you being mister Nate..?


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## Speedub.Nate (Dec 31, 2003)

patineto said:


> Were have you being mister Nate..?


Skiing / boarding / playing in the snow. With the wet weather, the bikes have been on hiatus.


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## patineto (Oct 28, 2005)

Speedub.Nate said:


> Skiing / boarding / playing in the snow. With the wet weather, the bikes have been on hiatus.


Hey that bets working, working anyday..

Good for you.

Actually I love riding in the mud even if sometimes is not the best for the envoriment, then again is not much damage I can do compare to something like this.


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## Speedub.Nate (Dec 31, 2003)

patineto said:


> Hey that bets working, working anyday..
> 
> Good for you.
> 
> Actually I love riding in the mud even if sometimes is not the best for the envoriment, then again is not much damage I can do compare to something like this.


Well, I have a somewhat unusual work schedule. With the late start to winter, I was happily riding bikes up to New Years, and now have do my best to get as much time on the slopes as I can.

But to get this post back on topic, the only place for "disc breaks" up here are when they drag you down the hill on a backboard!


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## patineto (Oct 28, 2005)

Speedub.Nate said:


> Well, I have a somewhat unusual work schedule. With the late start to winter, I was happily riding bikes up to New Years, and now have do my best to get as much time on the slopes as I can.
> 
> But to get this post back on topic, *the only place for "disc breaks" up here are when they drag you down the hill on a backboard!
> *


Amen for that One..

Nice to see you posting around, even if emplys you are not up there anymore playing around.


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## befoot (Mar 11, 2006)

> Make sure the fork is the Tandem version of the FR; very important if you're running disc brakes


 thanks for the heads up Alex,I know John said he was using a disc brake on this fork. but I'll have to check on it.

looks like 203's are no problem, thanks Nate

dropped down to the valley of the sun today. it was good to ride a dry trail in the warm sun shine with no snow or mud for a change. 
so Ricardo,we'll be happy to send you some more mud :]
I will be seeing "mister Cunninham" next weekend at Old Pueblo town.

cheers everyone


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