# Track end dropouts and discs?



## olliepen (Jan 4, 2010)

Hi

I have an old giant cadex that I want to run as a single speed with discs. The rear dropouts are removable so I'm going to get some new track style dropouts made, but I want to include a disc tab on the none drive side - however I'm not sure how to make the disk tab adjustable. I have seen some frames where the mounting holes for the caliper are more like slotts, but no two look the same - is it simply a case of making the caliper mounts slotted in the same direction as the dropout?



















https://www.hayesdiscbrake.com/pdf/Rear%20QR%20IS.pdf


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## Sparticus (Dec 28, 1999)

Yes.

The slotted disc mount on my On-One with horizontal track ends is within the rear triangle. Makes rear wheel removal easier because I don't have to loosen/remove the caliper in order to extract the wheel.

--Sparty


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## voodoochild (Feb 20, 2004)

Bianchi has a similar, slotted brake mount to what sparticus posted. Though it's in the more "traditional" location behind the seat-stay/above the axle, rather than between the stays like the on-one. I seem to recall that the slots are longer. I will snap a pic for you when I get a chance.

I actually like the look of that On-one mount. It sorta makes sense (to my little brain...) to put it where they did. Any issues with that location Sparticus?


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## olliepen (Jan 4, 2010)

Sparticus said:


> Yes.
> 
> The slotted disc mount on my On-One with horizontal track ends is within the rear triangle. Makes rear wheel removal easier because I don't have to loosen/remove the caliper in order to extract the wheel.
> 
> --Sparty


Unfortunatly it is not possible to put the disc mount forward of the dropouts as I'm contrained by the existing frame / chainstays, but do you see any reason why this slotted dropout wouldn't work if the caliper where in the more "traditional" position?


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## Sparticus (Dec 28, 1999)

No issues.

--Sparty


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## bikeny (Feb 26, 2004)

How about something like what Surly uses?


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## metrotuned (Dec 29, 2006)

*IS brake tab, lead by example*

Or what Bianchi uses (2004 Bianchi SASS and similar generation single speed 26" models) - the slots in the IS disc tabs allow for adjustment of the caliper in relation to where your hub sits in the track drops:


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## olliepen (Jan 4, 2010)

great stuff - this is the kind of thing I'm looking for! Just had another thought though... the frame is pretty old (early 1990's), I'm not sure what the distance between the dropouts is - but will a SS disk hub fit?


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## Wily (Feb 18, 2004)

illnacord said:


> Or what Bianchi uses (2004 Bianchi SASS and similar generation single speed 26" models) - the slots in the IS disc tabs allow for adjustment of the caliper in relation to where your hub sits in the track drops:


To remove the rear wheel, do you have to loosen the brake caliper and rotate it out of the way so that the disc can clear it?


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## voodoochild (Feb 20, 2004)

Nope, the wheel comes out with no issues. At least for me, on my SASS.

For the o.p., re: drop-out width/spacing. That frame should be the standard mtb width -- 135mm. I would think that you'd just have to get the horizontal dropout fabricated as you'd planned, with the brake slots in the right place, and you should be golden.


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## byknuts (Aug 9, 2008)

why not make yourself some black cat style swinging dropouts?
your frame's got 2 holes already, you're basically halfway there :thumbsup:

can't tell if you've got the clearance for the swinger to the front, but take a look, seems the neatest option IMO.


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## chumbox (Jan 9, 2008)

Why not get Paragon sliders. Takes the pain out of the whole scenario.


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## mack_turtle (Jan 6, 2009)

my monocog has horizontal dropout slots and slotted tabs for disc brakes. the brake is never in the way when i pull the wheel out.


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## scooter916 (Jan 2, 2006)

bikeny said:


> How about something like what Surly uses?


love the left side drive fixie with disc brake but your chain is upside down


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## rivrmutt (Mar 14, 2006)

mack_turtle said:


> my monocog has horizontal dropout slots and slotted tabs for disc brakes. the brake is never in the way when i pull the wheel out.


I second that.


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## buddhak (Jan 26, 2006)

Why bother with rear discs at all? Seems like you could save yourself a lot of grief in exchange for a barely perceptible (unless you live in Dagoba) decrease in braking power by just running the bike as a mullet. My 2 cents...worth every penny, no doubt.


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## olliepen (Jan 4, 2010)

buddhak said:


> Why bother with rear discs at all? Seems like you could save yourself a lot of grief in exchange for a barely perceptible (unless you live in Dagoba) decrease in braking power by just running the bike as a mullet. My 2 cents...worth every penny, no doubt.


I'm starting to think that the rear disc might be a step too far myself. Forgive me - mullet?


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## LIFECYCLE (Mar 8, 2006)

I love those old Cadex frames,wouldnt mind one myself.


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## voodoochild (Feb 20, 2004)

mullet = business in the front, party in the back. dude.


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## umarth (Dec 5, 2007)

Measure the distance between the dropouts. If it is 135ish then you are probably set. I think by early 90's 135mm spacing started being common. I have an '89 rockhopper with 130mm spacing, but it is steel and the 135mm hubs fit with no problem. I have rockhopper that I am not sure of the year, but likely early 90's and it is 135. 

If you live in a dryish climate, rim brakes will probably do the job fairly well. I ride rim brakes at time in the summer and I think they work pretty well.


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## flatulentfox (Aug 27, 2004)

scooter916 said:


> love the left side drive fixie with disc brake but your chain is upside down


He may ride backwards alot...


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## Sparticus (Dec 28, 1999)

That is a cool / weird setup. Personally I would not want my greasy chain to be in such close proximity to my disc brake rotor.

--Sparty


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## buddhak (Jan 26, 2006)

olliepen said:


> I'm starting to think that the rear disc might be a step too far myself. Forgive me - mullet?


Disc up front, v-brake out back. Still cooking with gas.:thumbsup:


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## weather (Jan 12, 2004)

your chainstay and seatstay aren't designed to take torque around the dropout.


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## olliepen (Jan 4, 2010)

weather said:


> your chainstay and seatstay aren't designed to take torque around the dropout.


No - but this fella seems to be getting away with it!

http://www.retrobike.co.uk/forum/viewtopic.php?t=74979&postdays=0&postorder=asc&start=15


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## jerky (Mar 26, 2007)

I hadnt seen that thread, but I dont like the look of the disc arrangement and would share concerns over its longevity.


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## bishopdante (May 22, 2009)

weather said:


> your chainstay and seatstay aren't designed to take torque around the dropout.


Actually, so long as the stress is transferred from the dropout to the axle, there's nothing too terrible going on with the frame.

So long as the dropout isn't changing shape from bolt to bolt, I really don't see how it's going to be a problem for the frame to be stressed that way, I'm pretty sure that dropping off and landing heavily on the back wheel is way worse in terms of stresses and twisting forces.

There's a big limit to what forces a back brake caliper can create, when you over-brake the back wheel locks up, right?

The connection between the ground and the tire is the limit of the stress than can be conferred by rear wheel braking, so I very much doubt one could twist the dropout off the frame.

However, the glued surfaces would not benefit from the stresses, but I doubt that they're much more damaging than the vibrations from riding down stairs.

Am inclined to think that so long as the caliper mount is fairly beefy, there is very little to be concerned about, since the caliper mount is not actually fixed onto the frame, or putting pressure on the wall of a tube in ways that might damage the frame.

Certainly one can't just go welding caliper mounts onto frames anywhere, but there's very little risk in bolting an A2Z disk adapter onto the dropout of any non-disk frame. Problem with those is they're heavy.


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