Disk for Rohloff hub - BB7 compatable

[rifraf]

Hiya,
I'm looking at getting a disk for my Rohloff hub. It needs to be 160mm max for the frame I'm looking at and needs to work using a BB7 brake unit.
Thus far I've had recommended:
http://www.this link is broken.au/hope-mono-mini ... hloff-hub/" onclick="window.open(this.href);return false;
I know nothing about disk brakes and my build when it happens will be my first disk braked bike.
Anyone got any suggestions/comments/ramblings to offer before I bite the bullet?
Cheers

[rjk]

the only thing to check is the width of the braking surface, the bb7 pads are larger than the bb5 sothe pads might rub on the arms and pulsate while braking if it is not large enough

[MattyK]

SJS are good for hub gear parts. (Note GBP prices include VAT, it will be deducted at checkout)

http://www.sjscycles.co.uk/page/find/?n ... tor&page=1" onclick="window.open(this.href);return false;

I don't get rotor compatibility. How hard is it for bike brake manufacturers to quote OD, ID and thickness like every car brake rotor manufacturer can?

[rifraf]

I don't get rotor compatibility. How hard is it for bike brake manufacturers to quote OD, ID and thickness like every car brake rotor manufacturer can?

the only thing to check is the width of the braking surface, the bb7 pads are larger than the bb5 sothe pads might rub on the arms and pulsate while braking if it is not large enough

Thank you both for the replies. I've only just started but I've invested an hour already trying to look up spec on the rotors and not having much joy.
MattyK I completely agree with your sentiments above.
RJK as said, I cant check on the width or anything else until I can find some sort of spec or compatibility sheet but will take your advice when/if I do.

[cobba]

It needs to be 160mm max for the frame I'm looking at

Not saying that you need a bigger rotor but why can't one be put onto the bike.

If you're worried about compatibility then get a Avid G2 rotor, it's the stock rotor for the BB7.
http://www.this link is broken/Mode ... elID=41704

Formula rotors seem to be commonly used with the BB7's and internal gear hubs, I've seen some photos on another forum.
Formula rotor in the slideshow: http://www.co-motion.com/index.php/sing ... no_rohloff

BB7 + Hope Sawtooth:
http://farm8.staticflickr.com/7040/6795 ... 5ba2_z.jpg
http://farm6.static.flickr.com/5291/539 ... e1fc_b.jpg

I doubt that there would be a problem using the Hope Sawtooth with a BB7.

[rifraf]

It needs to be 160mm max for the frame I'm looking at

Not saying that you need a bigger rotor but why can't one be put onto the bike.

Hi Cobba,
thanks for your reply and all the links/info.
As to your question
http://surlybikes.com/bikes/ogre" onclick="window.open(this.href);return false;
under "frame highlights":
Brake compatibility: Disc and rim brake compatible. Disc mounts are 51mm IS Rim brake pivots are removable. Note: rear disc brake is limited to 160mm maximum rotor diameter and requires the use of Surly caliper adapter

[cobba]

and requires the use of Surly caliper adapter

The 160mm Surly Adapter looks similar to a 180mm or 200mm rear adapter.
Got to love it when a company says you have use a specific item they made.
In a few years time getting one of those adapters will be as hard as it is now to find a stupid Pro Stop Adapter.

[rifraf]

and requires the use of Surly caliper adapter

The 160mm Surly Adapter looks similar to a 180mm or 200mm rear adapter.
Got to love it when a company says you have use a specific item they made.
In a few years time getting one of those adapters will be as hard as it is now to find a stupid Pro Stop Adapter.

Yeah well the budget is already very tight on this build. I dont have the knowledge or the funds , never mind the inclination, to start experimenting on possible brake rotor fitment. I just want a rear disk brake that will work and give a minimum of fuss.
I'm hoping a cable brake will offer this.
I dont think there is any mentioned restriction on the front brake so will go for as large a disk as gives great braking balanced with bang for buck.
I dont even know anything about the hows and whys of rotor size.
Is it safe to assume the larger the rotor the less it will heat up compared to a smaller one?

[Uncle Just]

Rif if you are not aware of it, the Rohloff disc hub takes a 4 bolt rotor. This is unique to Rohloff as all other rotors are 6 bolt. I'd go Avid G2 as mentioned above. Size? 160mm rear s/be sufficient. Put a 180 if you like on the front.

[rifraf]

Rif if you are not aware of it, the Rohloff disc hub takes a 4 bolt rotor. This is unique to Rohloff as all other rotors are 6 bolt. I'd go Avid G2 as mentioned above. Size? 160mm rear s/be sufficient. Put a 180 if you like on the front.

Hi Uncle Just,
thanks for the heads up.
I was made aware of this early in the piece but thanks for confirming.
Is there a big advantage to the G2 above the Hope Mono Mini Rotor (SAW) I linked to in my first post?
Wiggle appears not to stock G2 in 4 bolt so I cant do a price comparison.
I"m happy to put a 180 on the front but have yet to be told what the advantage is.
Cheers

[Mulger bill]

More metal and a larger surface area means it will handle heat better, not to mention that the longer lever will mean better braking.

I'd be making sure your fork and it's dropouts are suitable to a big rotor before forking out. Nobody can provide a link to the reasoning behind this...

[rifraf]

not to mention that the longer lever will mean better braking.

Hiya Shaun, could you expand on this please? What longer lever?

I'd be making sure your fork and it's dropouts are suitable to a big rotor before forking out. Nobody can provide a link to the reasoning behind this...

Should be OK on this I think as Surly say of their fork:

"TIG-welded 4130 CroMoly, 80mm suspension corrected, tapered straight blade. Low- and mid-blade fully threaded through-blade rack eyelets; fender mount eyelets at dropout; 1-1/8" x 260mm threadless steer tube, 51mm disc mount (203mm max. rotor diameter), removable cantilever pivots, line/housing guides"

[Mulger bill]

The longer lever is from the greater radius of a larger rotor, wish I could remember which class of lever it is, been a long time...

If Surly rate their forks for a max 203 rotor then my previous comment can be safely ignored

[rifraf]

The longer lever is from the greater radius of a larger rotor, wish I could remember which class of lever it is, been a long time...

If Surly rate their forks for a max 203 rotor then my previous comment can be safely ignored

The lever stuff is over my head but no worries.
As to the Surly fork, its a weighty illegitimate so I'm suspecting no shortage of ferrous material to offer a long fatigue life.

[Uncle Just]

Is there a big advantage to the G2 above the Hope Mono Mini Rotor (SAW) I linked to in my first post

Compatibility. Avid BB7 and Avid rotor make for good braking ime. I made the mistake of using a Shimano Ice Tech rotor with my BB7 brakes. Brake fade and warping resulted as the Ice Tech setup is part of purpose built system ie you should use the caliper and specific rotor for it to work as designed. I'm not familiar with the Hope rotors but others more familiar with them say they'll work.
As MB wrote, the larger front disc is useful for the reasons given. Implicit in his explanation to go larger on the front, particularly if carrying weighty touring gear, is that the front brake does most of your braking.

[il padrone]

The lever stuff is over my head but no worries.

Don't worry too much about the physics, just remember - a larger radius disc is equivalent to greater leverage from your brake action, given the same wheel diameter.

I must say that touring is not the same as MTB off-road trail riding. The smaller diameter discs are generally excellent for any steep descents or sharp braking you are likely to encounter, even when doing high country bush tours. I still run the V-brakes and am more than happy with them. Then there is also the choice between cable and hydro, a more critical choice. Most cable discs are little better than good V-brakes. Hydraulics on the other hand adds extra complexity in any major brake overhauls while on the road.

BTW if your Surly fork has "through-blade rack eyelets" you could set the bike up with the Tubus Duo front rack and avoid the hoop over the wheel.

[WestcoastPete]

I'm pretty sure the front disc rotor on my expedition bike is 160mm and is more than powerful enough. It went really well in the mountains in the USA recently, but admittedly they weren't worked as hard as they might be on a more undulating and challenging descent. I'd confidently take on such a descent though.

I've got a disc on my Rohloff on that bike too. Pretty sure it's an avid g2, but the bike has already been shipped to my new home so can't check. One small issue is that the SON disc hub uses a lock ring to hold the disc on, same as a cassette lock ring. That means having to carry a tool just to get this rotor off. If you can get a hub that uses a rotor mounted with Allen bolts, you'll save yourself this problem.

BB7s are sweet as by the way, especially with the associated levers (can't remember the name). Very easy to adjust, very powerful yet modulated, normal brake cable and easily changed and packable pads. I've found this method of setting then up to be excellent.

Sent from my GT-I9100 using Tapatalk 2

[rifraf]

Most cable discs are little better than good V-brakes. Hydraulics on the other hand adds extra complexity in any major brake overhauls while on the road.

BTW if your Surly fork has "through-blade rack eyelets" you could set the bike up with the Tubus Duo front rack and avoid the hoop over the wheel.

I'm wanting to see how it goes not wearing out rims whilst sacrificing disks to the wearing parts deity for appeasement instead.
I wont be going hydro as I suspect long term they require more maintenance which is something I try to avoid.
Thanks for the "Tubus Duo" tip.
Cheers
Aidan

[rifraf]

I'm pretty sure the front disc rotor on my expedition bike is 160mm and is more than powerful enough. It went really well in the mountains in the USA recently, but admittedly they weren't worked as hard as they might be on a more undulating and challenging descent. I'd confidently take on such a descent though.

Hi Pete,
enjoyed reading of your framebuilding adventures on CGOAB

I've got a disc on my Rohloff on that bike too. Pretty sure it's an avid g2, but the bike has already been shipped to my new home so can't check. One small issue is that the SON disc hub uses a lock ring to hold the disc on, same as a cassette lock ring. That means having to carry a tool just to get this rotor off. If you can get a hub that uses a rotor mounted with Allen bolts, you'll save yourself this problem.

Are you moving from Darwin?
Yes I've been wondering about which brake version to go for (centerlock or 6 bolt), I think I'm leaning toward a 6 bolt courtesy of your advice.

BB7s are sweet as by the way, especially with the associated levers (can't remember the name). Very easy to adjust, very powerful yet modulated, normal brake cable and easily changed and packable pads. I've found this method of setting then up to be excellent.

Sent from my GT-I9100 using Tapatalk 2

Well thats a load off as I've not had much to go on but anecdotal evidence of how well they work.
Thanks heaps for the link as I'm sure it'll come in handy soonish.
Cheers
Aidan

[rifraf]

not to mention that the longer lever will mean better braking.

Aahh, I think we're discussing leverage? I was wondering for while if the cable lever actuating the pads was longer
depending on the rotor size for a while there. From IP's post I suspect its more the leverage of the bigger rotor causing more
stopping power?
Cheers
Aidan

[il padrone]

I'm wanting to see how it goes not wearing out rims whilst sacrificing disks to the wearing parts deity for appeasement instead.

Rigida Andra30 CSS rims have been my solution to that one. 13,000kms and they are yet to develop any brake scouring marks

[RonK]

BTW if your Surly fork has "through-blade rack eyelets" you could set the bike up with the Tubus Duo front rack and avoid the hoop over the wheel.

Not sure of any good reason not to have the hoop over the wheel. Aesthetics perhaps, but that's in the "eye of the beholder". But I have found it a very useful handle on several occasions.

[il padrone]

Aesthetics.

The Duo does the same job, weighs the same, can carry the same load. It's a very rigid rack. The Duo rack can be used similarly as a lifting handle.

[edit] Ah, a bit more compact to pack if you remove it for transport in airline bags/boxes. Small matter I know.

[RonK]

The Duo rack can be used similarly as a lifting handle.

Err, no. Not the way I've used it anyway. The hoop handle comes into its own when you need help to drag your fully loaded bike through a flooded ford, a bog hole or a sand patch, or to lift it into the back of a vehicle. I've encountered all these situations on tour.

And then there is the issue that the standard Ortlieb lower clips don't fit the 16mm Duo tubes very well, and you have to buy another set for a good secure fitting. Small matter I know.

[il padrone]

The Duo rack can be used similarly as a lifting handle.

Err, no. Not the way I've used it anyway. The hoop handle comes into it's own when you need help to drag your fully loaded bike through a flooded ford, a bog hole or a sand patch, or to lift it into the back of a vehicle. I've encountered all these situations on tour.

Yes, dealt with similar. The Duo can be used to lift, with panniers fitted, maybe not quite so easy one handed from the front, but fine otherwise. I generally do such dragging using the seat post and handlebars anyway - dragging using the hoop the bike tends to want to fall over sideways.

And then there is the issue that the standard Ortlieb lower clips don't fit the 16mm Duo tubes very well, and you have to buy another set for a really secure fitting. Small matter I know.

The Duo main support tubes are 16mm, but the pannier mount tubes are 10mm. Same as with the Tara.