Larry Lem 1

I see Santana has 10" rotors but they cost $180. (Gen 4 from Precision Tandems). There is a monster disk brake rotor at 255 mm from BicycleDesigner available at Amazon for $69, but they designed it to be an odd shape for some reason. Are there any other rotors out there larger than 203 mm? I'd try adapting a motorcycle disk but they run about .200" thick. I measured my 203 mm disk at around .075" thick.
Thanks

quemazon

What year is your tandem? Some of the Santanas around 2004 use 203mm discs (if you're lucky). I looked for 10" rotor alternatives (and found the same one you did), but eventually realized that my Santana was spaced for 203mm rotors. that simplified things considerably, as I could use Shimano ice tech rotors. They have been great.

Leisesturm

Do you even know if (probably not) your fork is rated to take a monster sized rotor? They aren't all up to the stress. Plus I would think that tires start to be a limiting factor in ultimate stopability even with 'normal' sized rotors. Most riders don't need more powerful brakes, they need to ride 3 to 6 seconds ahead of their brakes. Even the motorcycle riders have to do that, they ride 12 seconds ahead of their .200" thick rotors!

DKMcK 

Santana's, up until this year, had disc brakes only on the rear.

Larry Lem 1

I don't have a tandem. I race streamliners at the World Human Powered Speed Challenge in Nevada each September.
I was thinking of changing from a 406 front wheel that has a disk brake to a 650c wheel with a rim brake. I want to use that brake very minimally so as not to blow the tire. I'll be depending on the rear brake more. The rear brake is 406 wheel with a 203 mm disk. The dropouts are bolted to brackets that are bonded to the inside of the shell. As I may use a stronger rider who will go faster and require more braking during the 3/4 mile-long shutdown area, I want to increase the brake size in the rear for more heat capacity (not braking power). I do not have machining capability to make a dual disk rear hub and am looking for alternatives such as larger rotors.

OneIsAllYouNeed

Galfer is currently offering 223mm x 2.0mm rotors. Hope made 225mm floating rotors for a while... might be some old stock out there. TRP is rumored to have some 223mm x 2.3mm rotors coming soon.

Risse Racing offers a number of dual-disc front hubs. You might consider using rim AND disc brakes on the same wheel.

conspiratemus1

The bigger the rotor, the less the stress placed on the hub and wheel mountings (not more.) The rim is the biggest possible disc, right?
Good luck and success with your streamliner racing. Most of us just think about how you guys squeeze out more speed -- but the rider has to be thinking, OK, now how do I get this thing stopped?
Would a parachute help? I suppose it adds more complexity than it's worth maybe?

MikeAndJean

This photo shows the 225mm Hope rotors we put on our new tandem (a Ritchey Breakaway). They are great. When the calipers are adjusted correctly, we can slide the rear wheel, which is more braking than you need. This is with mechanical calipers.

sapporoguy

Looks great! What mount do you use in the rear to fit that rotor? Add something to a 203mm mount?

MikeAndJean

Yes, pictures being worth the proverbial kilo-words, here is a photo. Note the additional spacers directly between the caliper itself and the mounting.

sapporoguy

Thanks. What brand/size is that top bracket? And how thick the spacers?
I'm temped to try this on our Co-Mo Speedster with TRP HY/RD+Ice Tech rotor, which is better than the old BB7 but still not stoppy enough for my tastes.

MikeAndJean

Sorry but the middle piece, which appears black in this photo, has no part number or markings of any kind. I bought it at the local bike shop because it "looked" about right. Of course, it wasn't quite right. I had to add the spacers, which I measure to be 0.112 inches. As you probably recognized from the photo, the lower part, which appears dark grey in this photo, is a standard Shimano mount for 203mm rotors.

Chris_W

I spotted a 254mm rotor while wandering around Eurobike, branded as Now8. You can see it in their catalog on page 180 (or N21) with an adapter. They seem to have an online store that shows the rotor for 99 euros and the adapter for 18 euros. Unfortunately, I have no other knowledge about this brand.

Joint Venture

That sure looks like a dead ringer for the Santana Gen 4 rotor (pictured below)!

riceowls

I didn't realize Ritchey makes tandem frames! I have a breakaway cross and really like the idea. Does it pack into 2x suitcases?

MikeAndJean

It fits into two bags, one the same size as used for a Breakaway single. The second bag is slightly larger.

sapporoguy

Is this yours? How thick is that rotor?

Joint Venture

Yes, it’s our old 2001 Santana Sovereign tandem that we sold almost a year ago. I’m not sure how thick the braking surface is, and can’t measure since it’s gone, but the braking surface did not seem noticeably thicker than the Santana Gen 3 254mm one-piece steel rotor and the Avid 203mm rotor that preceded it.

sapporoguy

I recognized that tandem! Looks just like our 2000 Sovereign. I'm just wondering if the rotor is slim enough to fit in our HY/RD caliper; current disc is 1.8mm thick, I believe.

Joint Venture

I can’t imagine it wouldn’t work!

Chris_W

They sell exactly the same rotor in sizes down to 160mm, so I can't imagine it's any thicker than standard. I also zoomed in on the originals of the photos that I took at Eurobike, the thickness is not marked but it looks to be pretty normal.

Philphine

i have the bicycle designer one on one of my stretch cruisers (just on the front. still need to build the rear wheel to add the other). if you're meaning the outer flat sides, i think if the caliper is positioned well the contact area stays consistant. at least as best i can tell, as i welded the caliper mount on myself. in any event it seems to work well by it's self with no rear at the moment, also considering it's a pretty heavy bike (started with a coker monster), but i'll qualify that by adding it's a cruiser that doesn't see very high speeds.

StephenH

Presumably under sustained braking (long downhill, for example), you'd have the rotor heating up, but, regardless of how big the rotor is, you'd also have the brake pads and housing heating up. It may be that they're already at the point where bigger rotors don't really accomplish much.
Mounting two brake units on a single rotor might help keep the heat down if you didn't just twist the rotor into a pretzel.
Intentionally shifting airflow to the brake might accomplish more- something along the lines of a hood scoop on an HPV.