Help Needed For Brake Options For Non-Fatbike Wheel in Fatbike Fork

amberwolf

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As title says, I have a fatbike fork (originally from Luna, IIRC) with standard leftside disc mounts, and a standard (rear) disc compatible wheel (ex-stromer hubmotor), and need a good disc brake that will stop (or at least skid the wheel) a 600lb trike / rider / load from 20MPH.

EDIT for clarity:
I need to know *which* disc brakes would be capable of doing the above, so I can find an affordable source for one. (used or new, as long as I *know* that the used ones actually work. The brakes need to have good enough modulation to be able to simply slow down a little, or skid to a stop, or anything in between, without requiring both hands on a single lever to squeeze it hard enough to do any of those things. (my hands are getting arthritic, and sometimes randomly go numb (but still work, even though I can't feel them), to complicate matters).




(see the SB Cruiser thread for the actual trike and loads in question https://www.endless-sphere.com/forums/viewtopic.php?f=2&t=67833&start=850 )

I'd prefer cable-operated rather than hydraulic, because I can fix cable stuff roadside when inevitabely something goes wrong.


I broke my "good" suspension (worked, at least) fork's crown (and bent the steerer tube) in a collision, and I need to replace it with something other than the piece of junk spare I have on it at the moment.
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The best fork I have right now is a nonsuspension fatbike fork
dsc08157.jpg
which I want to use, because I have a rear DD hubmotor (from a Stromer) I intend to use on the front of the trike for a regen brake and redundant traction motor. (I have to make "torque plate dropouts" to bolt to the outside of the fork's dropouts, since the actual dropouts are insufficient for motor power, *and* are not wide enough by about 6-7mm; I could probably bend the steel fork wider, but still need torque plates/arms, but this is relatively simple to do).
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I've been pondering ways to make rim brake boss holders to put the arms close enough to the rims to work, and will try that if there isnt' a disc brake I can get at a reasonable price (I'd also have to change the rim on that motor to use rim brakes). But right now, I'm willing to throw money at the problem.


I also would like to add brakes to the rear wheels, but the frame isn't built for it right now, and would require significant modification to work, *and* one of the motors doesn't have a disc-mount cover anymore (had to remove the mount for a wiring fix), *and* the future axle replacement I'd like to do may not fit thru a bike disc rotor hole (leaving MC hydraulic discs as the only disc option I can think of).


(regarding adding the rim brakes, essentially I'd be taking the U-shaped section from a "normal" suspension fork, that has the brake bosses on it, and making a "box" that can be hose clamped (or some other form of clamp that prevents rocking and rotation) to the inboard side of teh fatbike fork legs. The U would then be welded to the front of the box. A second U would be welded to teh back fo the box, bosses pointing backwards, but at an angle that meets the rim correctly (unlike my present double-U brake setup on the previous forks, necessary to get sufficient braking to skid the wheel and/or stop the trike in a useful distance).
dsc08158.jpg
With some of the U's I have, like the one above, tehy might be able to be directly welded (or clamped) to the fork without intermediate hardware, for the front...but I still need something for the back one to make it sit at the correct angle for the bosses to be parallel to the rim curvature there).


(note: changed to more appropriate title)
 

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Alternately, if there's nothing affordable in disc that will do it, I have this Sachs IGH (7 speed?) with drum brake that I could build into a wheel (have to order spokes for whatever rim I have around here to use; rims cost too much to ship or I"d order one of those too just to start with a whole new wheel; maybe I can see what's at the few LBS I can get to that carry rims).
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Side note: Eventually I'm going to move the pedal chain drivetrain from the rear left wheel to the front, for a number of reasons, so that's primarily why I'm experimenting with the fatbike fork and the rear hubs.
--eliminates the chain passing thru and/or under the cargo deck
--simplifies the frame/box construction back there, including flattening the deck (no hump for the transfer sprocket/shaft)
--removes the need for any bicycle-part compatibility for the rear wheels
--removes the need to keep chain alignment or tension for the left rear wheel, which greatly simplifies dropout design / wheel installation & removal
--adds possibility for multiple gears at the wheel itself (not presently possible due to space restrictions and frame design and chain length from transfer shaft to wheel input sprocket)
I just have to figure out how to get the chain drive across the steering boundary without using a twisting chain (like I did on delta tripper's FWD), etc.
 
The way you have the hub in the fork, in the picture is the way you want it?
Would that cause problems because its not centered?

----------------------------

How far are you off on caliper to the rotor?

4.8mm spacers on the disc side, purchase at problem solvers. Shave it down if you need less, throw some washers into each bolt hole if you need a tad more spacing. You can even space out the caliper adapter, just see how it goes and dont make it too much!

:thumb: Get some 203 adapter mounts, and a 203 disc for that extra stopping power.

Hit up the hardware store for some steel to make your torque arms to fill in the gap on the non disc side.
or some 5mm washers - https://www.ebikes.ca/shop/electric-bicycle-parts/motor-hardware/spacewash5.html
TBH, that inside line looks perfect for a beefy steel plate t.a. and some hose clamps, it doesnt matter which way the axle flats are. Besides it gives your e-ride more "character" because its the subtleties that matter :wink:

Pro Tip: After you cut the steel for the axle flats to fit in snug and nicely, need to also cut a notch or two for atleast one hose clamp, I like to do 2 hose clamps.

----
edit: I would buy some steel plate, and get out the grinder and make your own v-brake, then thread the studs on.
 
I've been looking around at various disc brake options on Amazon and the like (because my brother will let me use his Prime for free shipping/etc on those items that qualify), but their search really sucks without a specific name / model / etc to put in. (it shows all sorts of completely unrelated items, and takes a lot of sifting thru, or else it shows nothing or almost nothing).

I also am looking at various bicycle-specific shops online, but I still don't know enough about what I'm looking at to choose. My only experience with disc brakes is the crappy stuff that comes on department store bikes, and none of that will even barely slow the trike. :/ Iv'e read here on ES of various types, like the BB7, that sound like they might work...but I just don't have the experience to know, and I can only spend the money once on this (and not a lot, at that--$100 is a huge amount of money, and that seems to be the bottom end of "good" disc brakes).

Read this article:
https://www.bicycling.com/bikes-gear/a20023166/the-beginners-guide-to-disc-brakes/
but didn't tell me anything I didn't already know.


I'm still working out the exact mounting for the rim brake U's, in case there aren't any disc solutions available, since I know my double-rim-brake-setup can lockup the wheel, but it *is* a PITA to setup and install, and has sometimes taken weeks to get it "just right" modifying the mounting hardware over and over, leaving me with insufficient braking until it is finally fixed. :( This would also require me to change the non-rim-brake-compatible rim on the hubmotor, or else just use a regular rear wheel that already uses a rim-brake-compatible rim, until I can get that done...and part of the reason for doing this fork change is to allow the use of the hubmotor in front as a backup motor and extra regen brake. (If I have to relace the wheel, I might as well put it in one of the 20" rims and stick it on the back in place of an MXUS when one of the axles breaks again)
 
Probably...and also inherit whatever problems the used parts have, and spend more money fixing those. (I have a number of used bikes already, mostly bought or given to me for parts for various things, and none of them were problem-free when I got them).

But since I also still don't know what specific brand/model brakes can stop this kind of mass, reliably, I don't know what bikes to look for that would have those kind of brakes on them.

Not going to spend money on something I have no idea if it will even do the job. I'd rather deal with my double-rim-brake hack. I know that works, eventually, once I've messed with it long enough. Or buy spokes / etc to lace up the drum brake hub into a wheel for it (which won't give me a motor up front...but would at least be a brake and give me the option of chain-driving the front wheel via pedals or motor)

But I'm perfectly willing to spend money (if I have enough of it) on something that *will* work, and be safe, and reliable.
 
Yeah, and you are a "search pro"
I heard good things about the Avid BB7's for cable actuated braking. I did purchase one, but never installed nor used.

Noted
I can only spend the money once on this (and not a lot, at that--$100 is a huge amount of money, and that seems to be the bottom end of "good" disc brakes).


Idea's

- Dual brake cable levers or variants. Disc + Rim perhaps?

- Dual brake disc rotor hub (perhaps on the rears, not front motor unless fabricate)

- 203's for extra stopping power

- More pistons on the disc caliper, like the Hope Mono 4 quad piston

- 255mm rotors - https://www.bicycledesigner.com/bike-parts/bicycle-brake/monster-disc-brake-rotor-255mm.html
https://www.bicycledesigner.com/bike-parts/bicycle-brake/monster-disc-brake-kit---front.html
255mm Rotor is $70, then use the bb7's, adapter is $50.
Either way its a neat website.
I see SRAM sells a 220mm disc rotor, you know it will be a quality product, unlike previous 255.
https://www.vitalmtb.com/photos/features/2017-Lourdes-World-Cup-Pit-Bits,10971/220mm-SRAM-Rotors,114605/iceman2058,94

-
double-rim-brake hack.

- Regen controller for braking

I would say with that amount of weight,
600lb trike / rider / load from 20MPH.
and a front brake, its in modulation of that power, and not locking it up.
https://forums.mtbr.com/brake-time/hydraulic-disc-brakes-vs-mechanical-266254.html




Conclusion:
With the hundred bucks, I am thinking dual rim brakes.

Plan A: I would drop the dime on Avid BB7 calipers with SRAM 220mm rotors. After confirmation on BB7's.
Plan B: Double rim brake hack
 
For cable actuated brakes, I think the TRP Spyke is supposed to be slightly better than the BB7 (two pistons as opposed to one). I don't have personal experience with either brake. I hate the Tektro Lyra cable actuated disc brakes on my Jamis. For that kind of weight, I think you might need a quad piston hydraulic brake like markz suggested. I bought a set of TRP Quadiem brakes for the bike I am currently building, but I haven't tried them yet and I am not even sure if they will clear the gap between the rotor and the motor I bought (MAC 10T). I couldn't find any documentation online. I need to get them out of the box and measure them.
 
FWIW, I measured the TRP Quadiems and they need about 16.1mm clearance between the motor and the rotor. Maybe a little more to be safe.
 
RunForTheHills said:
For cable actuated brakes, I think the TRP Spyke is supposed to be slightly better than the BB7 (two pistons as opposed to one).

That's my impression. Spyke needs more frequent adjustment than BB7, though.
 
Do you think a single Spyke would be able to skid the wheel, with something "slick" and relatively sticky like the CST City, in 26", for this monstrosity of a trike? I've seen them online for $80 or less.

Which kinds of adjustment does it usually need? Something at the lever end, or the caliper end?

(if it helps make the Spyke more usable for my situation, I have some Avid adjustable levers, that should work on cable-discs, AFAICT, so if I can get just the caliper and rotor, I can use those).

The brake *should* also have the regen of the rear wheels to do most of the braking...but there's always teh chance of electrical system failure, which is the primary reason for the front mechanical brake. (eventually I'll get rear mechanical brakes of some kind setup, but there's a lot of work needed to make that possible, more than I can do right now; and there's always some project I have to do, redo, or repair that has kept me from it since the beginning of this trike project).

If you don't think the Spyke will work, then what might, that is still cable-actuated?

I'd go hydraulic if I had to, but I don't like the roadside unserviceability, and the cost seems to be higher for the "same" thing vs cable (and I'd have to buy bleed tools, etc). (I see various ones for $150-$300+ online)

If the cost is too high, I'd rather just find another fork like I had (but with rim brake bosses built in), or just deal with the double-rim brake thing I've already proven to work on the fork that broke, but on this fatbike fork.
 
I don't know about the 255mm rotor that markz linked to, but a larger rotor does make a difference in stopping power. TRP sells a 180mm to 203mm adapter for their brakes. So you could run the Spyke with a 203mm rotor.
 
amberwolf said:
Do you think a single Spyke would be to skid the wheel, with something "slick" and relatively sticky like the CST City, in 26", for this monstrosity of a trike? I've seen them online for $80 or less.

Which kinds of adjustment does it usually need? Something at the lever end, or the caliper end?

I know your bike is heavy, but I don't know what portion of its weight is on the front wheel. I can't guess whether you'd be able to skid. I know that you can stop harder if you don't skid, though. Once the tire begins to slip, it has a lowered coefficient of friction.

Spyke is easy to adjust at the caliper. From what I can tell, it has a tendency to back the pads out with repeated hard application. So you have to crank them back in periodically.

I understand that your trike only goes 20mph, or maybe not even that fast. One front BB7 with a 203mm rotor is more than adequate for pedicabs that can weigh over 1000 pounds loaded. And the ones I'm most familiar with have 29" wheels, which puts the brake at a disadvantage. I think you'd do fine with any mechanical disc brakes for which you can get fully metallic pads.

I think you should consider using a triple clamp type fork (rigid for a chopper, not mushy for MTB). That would take most of the bending load off the steer tube and fork crown. You can adjust the legs up or down to fit whatever wheel you want to use. I just did a brief search and confirmed that they're available for fatbike front hubs as well as normal 100mm hubs.
 
Chalo said:
I know your bike is heavy, but I don't know what portion of its weight is on the front wheel. I can't guess whether you'd be able to skid. I know that you can stop harder if you don't skid, though. Once the tire begins to slip, it has a lowered coefficient of friction.
Oh, it's not that I *want* to skid, just that legally a bicycle here must have at least one brake that is able to skid the wheel on dry level pavement. (speed and other conditions not specified) Plus, if it can skid the wheel, then I know for sure I have the max braking possible out of it. ;) I usually have the rim brakes adjusted so that it requires most of strength to cause a skid, but will brake normally with normal strength.

I don't know for sure, but I think less than a third of he weight is on the fornt wheel. Maybe only a quarter. (have plans to move some weight forward, dunno when that will happen). Wish I had three scales to stick one under each wheel and see for sure. :) So let's guesstimate 25% of a guesstimate of 300lbs weight unloaded, around 75lbs. Or call it 500lbs with me on it, 125lbs on the front wheel, guesstimate.


Spyke is easy to adjust at the caliper. From what I can tell, it has a tendency to back the pads out with repeated hard application. So you have to crank them back in periodically.
That should be easy enough, as I don't need hard braking very often.

I understand that your trike only goes 20mph, or maybe not even that fast. One front BB7 with a 203mm rotor is more than adequate for pedicabs that can weigh over 1000 pounds loaded. And the ones I'm most familiar with have 29" wheels, which puts the brake at a disadvantage. I think you'd do fine with any mechanical disc brakes for which you can get fully metallic pads.
Ok, then probably the BB7 would work just fine, and I am sure I have seen posts around here about using fully metallic pads on those, available from more than one source.


The trike is usually ridden somewhere around 18-20MPH for most of my commutes; I may only go 10-15mph for non-time-critical rides that are not on car-occupied streets. 500lbs is about the typical loaded weight, but I can carry atl least 200lbs of dog or cargo in the back. If I have a trailer on there, I could pull more than the trike's own loaded weight on that (like when I hauled the piano home), but I don't ride more than 10-15mph with that kind of load, less if possible. And I will be adding brakes to the trailer itself anyway.

I think you should consider using a triple clamp type fork (rigid for a chopper, not mushy for MTB). That would take most of the bending load off the steer tube and fork crown. You can adjust the legs up or down to fit whatever wheel you want to use. I just did a brief search and confirmed that they're available for fatbike front hubs as well as normal 100mm hubs.
I have had a plan to use one for some time; I'd even arranged to buy the crown clamps and stuff from a member here, but then he sold them to someone else instead, in the middle of me paying for them. :roll: Before the fire I had a crappy fork like that, which Iw as going to use the crowns from with legs from something else or making my own, but like quite a few other things, someone else thought they should have it, before the house was redone and I could move back in. :(

At the moment, I have the bottom clamp-on crowns for such a fork, in something like fatbike width (a bit wider, actually) (and the crappy legs for it). I have to make the top crown for it; not sure out of what yet, but I can probably layer steel plates and cut them out as a copy of the aluminum part I already have. (found the bit I do have at goodwill for a few dollars) I'll probably just make non-suspension legs for it, since that's simple, and worry about suspension later if it gets to be too much of a problem without it; same as I'm doing with the fatbike fork right now. (some pretty big holes and such in the roads around here). I have a good idea how to build a suspension fork that uses a four-bar-link type "rear triangle" for the suspension and wheel holder, but that's a project for the future. I want to keep it simple, one step at a time, for now.


I even thought about welding stub tubes to the top of the fatbike fork tubes, to continue up parallel to the headtube/steerer, and then use the one crown I do have to clamp to all of those, to turn it into a stiffer fork.
 
RunForTheHills said:
I don't know about the 255mm rotor that markz linked to, but a larger rotor does make a difference in stopping power. TRP sells a 180mm to 203mm adapter for their brakes. So you could run the Spyke with a 203mm rotor.
Yeah, I'd probably use the largest rotor I can get adapters/etc for. (larger rotor size is one reason I like rim brakes better, because I am almost always in dry conditions so I don't have to worry about surface contamination or wetness, except during rare rainstorms,a nd with the koolstop pads I've had little problem with that, either).
 
FWIW, the avid levers I have are the same as these
https://www.amazon.com/Avid-Speed-Dial-7levers/dp/B07BYFZKMS/ref=pd_sbs_468_5/141-2326391-1041567?_encoding=UTF8&pd_rd_i=B07BYFZKMS&pd_rd_r=c78ac56e-6a4c-11e9-867c-c5b0dbebe95a&pd_rd_w=9Dqj7&pd_rd_wg=09zak&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=D6RPJQTDAG2MCW977VKT&refRID=D6RPJQTDAG2MCW977VKT


I found a few options for the BB7 on amazon; one doens't come with the moutning bracket (is just the caliper)
https://www.amazon.com/Avid-Mechanische-Disc-Brake-Bicycle/dp/B01EKOEGPG/ref=pd_sbs_468_1/141-2326391-1041567?_encoding=UTF8&pd_rd_i=B01EKOEGPG&pd_rd_r=bf0f4b3f-6a4c-11e9-94d4-49728df24266&pd_rd_w=7C8d7&pd_rd_wg=gT712&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=ZXDZ9R4R0VWT5EG75EMQ&psc=1&refRID=ZXDZ9R4R0VWT5EG75EMQ

This one is a front/rear pair that has the 160mm rotor, etc:
https://www.amazon.com/Avid-BB7-Front-Rear-Rotor/dp/B00403GRE6/ref=pd_day0_hl_468_4/141-2326391-1041567?_encoding=UTF8&pd_rd_i=B00403GRE6&pd_rd_r=bf0f4b3f-6a4c-11e9-94d4-49728df24266&pd_rd_w=WsSCW&pd_rd_wg=gT712&pf_rd_p=ad07871c-e646-4161-82c7-5ed0d4c85b07&pf_rd_r=ZXDZ9R4R0VWT5EG75EMQ&refRID=ZXDZ9R4R0VWT5EG75EMQ

this one sometimes comes with one caliper (unspecified f/r) and sometimes front/rear, and no adapter/mount/disc/etc.
https://www.amazon.com/Avid-Brake-BB7-Platinum-rotor/dp/B01EKOE6GA/ref=pd_sbs_468_4/141-2326391-1041567?_encoding=UTF8&pd_rd_i=B01EKOE6GA&pd_rd_r=bf0f4b3f-6a4c-11e9-94d4-49728df24266&pd_rd_w=7C8d7&pd_rd_wg=gT712&pf_rd_p=588939de-d3f8-42f1-a3d8-d556eae5797d&pf_rd_r=ZXDZ9R4R0VWT5EG75EMQ&psc=1&refRID=ZXDZ9R4R0VWT5EG75EMQ


one option for pads
https://www.amazon.com/Avid-Juicy-Organic-Steel-Brake/dp/B000VT2F0I/ref=sr_1_8?keywords=avid+bb7&qid=1556521439&s=sporting-goods&sr=1-8



I have some rotors, I think they're 180mm, and 160mm. Don't think I have anything bigger unless I can make it out of plate steel.

Might find other choices; still lookign around. Havne't looked at bike shop specific sites yet.
 
You want the mountain bike version and not the road bike version for your levers. The cable pull is shorter for road brakes/levers. This one includes the rotor with an option to choose a 200mm rotor (the second link in your list). I think that is the one you want.

https://www.amazon.com/Avid-BB7-Front-Rear-Rotor/dp/B00553YPEY/ref=pd_day0_hl_468_4/141-2326391-1041567?_encoding=UTF8&pd_rd_i=B00403GRE6&pd_rd_r=bf0f4b3f-6a4c-11e9-94d4-49728df24266&pd_rd_w=WsSCW&pd_rd_wg=gT712&pf_rd_p=ad07871c-e646-4161-82c7-5ed0d4c85b07&pf_rd_r=ZXDZ9R4R0VWT5EG75EMQ&refRID=ZXDZ9R4R0VWT5EG75EMQ&th=1&psc=1
 
Thanks. The largest rotor I can use is the best option, and since that has the whole thing (except lever/cable) then it's the best deal; after poking around I couldn't find anything better with quick free shipping that also had the adapter and rotor...and all the separately available parts would cost more than this package.
 
Hmm. I guess I forgot to come back and post the results. :oops:

Anwyay, I got the Avid BB7 with 200mm rotor, and it arrived as a complete kit with all brackets/bolts/etc.

Mounted it up, installed the fork and wheel and it worked great, plenty of modulation and more than enough stopping power to skid the wheel.

The fork, on the other hand, sucks. :(

Complete info and pics over here:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1466757#p1463761
 
Just a final note:

The Avid BB7 brake works great, in the new fork built after the fatbike fork failed; it's referenced in the posts after the linked one above.

I'm still on the original pads, they still give more than enough braking force to easily skid the wheel; my traction limit appears to be the weight on teh front end vs the rear.
 
Update after almost a couple of years:

The same caliper and rotor are still working, though I've gone thru a couple sets of pads (unfortunately I haven't been noting mileage over time consistently, so I don't know how many miles it takes to go thru them...I'd guess at about 1000 to 1500 miles per set). First set was original Avid that came with the caliper, second was another Avid out of a caliper I havent used yet (havent' rebuilt the rear to hold the calipers yet, so only a front brake so far). Third set I've just started using is "Dymoece" from Amazon:
https://www.amazon.com/gp/product/B07GCW273S/
"Resin,Semi-Metallic,Sintered Metal" version, works fine in dry and wet, but no idea on wear yet.

The rotor itself shows definite wear (is VERY shiny ;) ).

The caliper also has wear, though, because, as it took me a while to find, the mounting tabs on the crappy "Element9" fork that the lowers / dropouts came from for my custom no-suspension fork (as I still haven't had the chance to finish it using the pedicab dropouts with their superthick tabs) bend under load, and after a while stay that way, and bend more, then stay, etc. So it has been diagonally wearing the pads, and cutting into the caliper itself. :(

So I ended up doing a quick fix of cutting the thin tabs off another crappy fork and welding them against the outboard side of the tabs on this fork. Only been two days since this was done, so can't tell yet if this is a good fix or not, but it is still working so far.

Permanent fix is to put the pedicab dropouts on there. I dont' recall their exact thickness, but it's nearly 10mm. :shock: Don't think I'll have a problem with *those* bending under load. :lol:

But the brakes themselves still work great. :)
 
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