ricardo kuhn

I got my self a "NewToME"Ibis tandem a few days ago and I decide to go ToTown and make it into a very capable singletrack machine,the first step to improve the brakes

here is a report of the result..




basically the problem is that rim brakes on a tandem get super hot when you are going downhill do to the extra mass, but is a few things you can do...get the biggest RIMs you can find since the more surface that is expose to the elements the faster they are going to cool down, a basic thermal exchange, in my case i when with the super oversize trailpimps.



well even then I was looking for more reliable Braking power so i decide to install a set of Disc brakes on the bike,,the main problem was how to operate the two sistems at ones,,
for a few days i play with the idea of ussing a old "diacompe" double wire sistem and run one of the wires to activate the brake pump and the other to the v-brakes,,i know i can be done, some of my old BMW motorcycles use that sistem but was just to complicate and dificult to control modulation..

so i got some old C2 Hope levers and i flip them upsize down, this way my hands can be place at the end of the bars with out much trouble and since the C2 is a "airless" sistem does not make a diference if is upsize down or right side up...

anyway sorry if this is confussing,,my Ingles do suck

here are the pictures of the diferent possitions.

V-brakes ON


Disc brake ON


the TWO brakes at the same time ,can you say Stooooopies


i don't really like Bar-ends that much but in this case they help to protect the reserviors.

another little trick, the Hose from the Hope brake was getting on the way of my hand so i build a small "bridge" ussing a ziptie and some string rap(vertical line from the bar to the hose) the way is done you constrict the ends of the ziptie with the stringrap (with heat to make them rigid) and then leave the rest untouch so is kind of stiff(you can control how flexible it is by heating more or less of the rap)..works like a dream anyway.



another beauty about the C2 calipers is that is extremlly easy to control the lever travel and the pad engagement by moving the silver knob, so if i'm just riding around i release the fluid pressure and i have NO drag from the disc,,when i need the extra braking power I move the Knob as much as i need(takes 5 seconds at the most) and have extremlly powerful braking


here are some more pictures of the almost complete bike (I need to re-weld the post for the rear brake and also get a really long hose) before I'm done.




Pretty Evil or What!?!?!?


I hope you guys and gals like the little project

geeklpc1985

Nice I want one!

Very Cool.

Super Geek

TandemGeek

A couple thoughts....

I don't want to come off as an alarmist, but the combination of the Surly fork with Hope 04DH / Enduro brake caliper may warrant some extra attention if it's the same fork depicted here. If so.... 1. Did you confirm with Surley that the fork is robust enough for your use on the tandem given your total team weight? 2. If there are lawyer lips on the fork, don't grind them off. 3. Make sure you stick with the steel XT skewer and keep it tight. 4. If you should ever notice that your skewer doesn't seem as tight as it should be after a ride or if the lever seems to have moved, be extra attentive to tightening down the skewer and if it continues to shift or loosen it may be time to get a new skewer or to be less aggressive in your use of the front disc. While I'm not sold on the disc brake ejection scenario as a problem for the masses, the combination of a rigid fork that has rear-facing quick-release drop-outs and a 4 pot downhill disc brake caliper with large diameter rotor on a tandem is just too similar to the equipment used on another off-road tandem that started the entire technical debate.

As for protecting the C2 levers, I'd be a little concerned about bashing them during a crash as the end of the bars routinely get slammed into the ground on front wheel wash-outs... not all that uncommon on tandems.

As for the redundant brakes, having bombed around on some fairly technical single track on several different off-road tandems, the four-pot downhill hydraulics from Hope & Magura with 203mm rotors front & rear are more than adequate for just about everything you encounter off-road. Thus, if I was looking for some added speed reduction I'd probably go with dual discs and fit some old XT Cantilever brakes to the rear with a large-mass rim such as the one you have selected that would be controlled by the stoker and used as a drag brake on those rare occasions when the dual discs were pushed to their limits.

Otherwise, it's cool-looking set-up and you just gotta love any Ibis...

ricardo kuhn

mister Tandem geek thanks for your concerns

let see,,the Surly I have is the INSTIGATOR,,that is a tandem aprove fork, not the lame typical surly fork.

second I'm waiting for the "Real" fork, for this bike,,a FUNN 20 axle dual duty fork(disc and Canti's)
is also rated for tandem duty and really really big rotors..

I'm right there with you,,QR's are weak and scarry evn if none of them ever fail on me after 25years of mountain biking i'm always waiting for that Oh S^^T moment, actually i know paul solon(raam racer) and the lawyer that got to put "ears" in every fork, so i'm very aware of the risk factor..

about the brakes when I live in colombia I melt and explote more tubes that i care remenber in my Blue Ibis tandem do to the extreme downhill angles,,or maybe lack of better equipment (scott sel fenergise brakes with scott mathuser red pads), but even if currentlly i'm a very serius motorcycle rider and somehow mecanic, I still have more trust on Steel wires than hydrolic fluid, call me pesimistic if you want but I think i can fix a damage brake wire easier than I can refill a puncture hydrolic line,,

I have Hope TI-6 on my Nicolai downhill bike so i'm extremlly aware of the capabilities of the sistem, but the way I see it ,i'm never going to venture far enogh from civilization on my downhill bike that I can not walk the bike if need too, the tandem is far more capable of long distance not to mension riding with a single brake(even the front) will be a little scary..

I quess i spend way to much time at the "murphy's law" training camp, so I always try to build sistem upon sistems just in case that sad day comes along.

I will like to see your face the day I finish my tandem rack for my Motorcycle,,,Oh man that one is goingto be super dupper scary

for now i leave you with a foto of my current carrior with a half bike

one of my "Heavy weapons" on board..the tandem mount is going to be far more of a compromise,, maybe i will never use it,, even if I'm almost done with it.. I know S&S cuplers make a lot of sence except for my bank account at the moment.



this day i was coming from a swapmeet with a lot more crap than I spect it

TandemGeek

Good that it's more robust and that a new 20mm is on the way. As I said, in looking at the photo of the Instigator it sure looks like they used a set of drop-outs designed for curved fork blades on a straight bladed fork which moves the orientation of the drop-out openings rearward... not a good thing for disc-equipped fork.


Back to your comment about running a dual cable or cable splitter system, it would have been interesting to see if the combination of rim and Avid's BB7 mechanical disc brake may have lent itself to that application, i.e., could you get the cable pull adjusted well enough for both brakes to work pregressively in tandem (so to speak),


We have or at least had a member of our cycling club who would tote his personal bikes around on a side-mounted custom rack that he fitted to his Harley cruiser and I've pondered how I'd rig up a similar set-up for my Honda CBR1100. I've come to the conclusion that sportbikes aren't as adaptable to such mods and I'd be better off getting a Goldwing with a small trailer for hauling bikes around, as a few inventive tandem teams have done in the past.

galen_52657

Ricardo,

You are one inventive dude!!!! I love your work!!!! Carry on my good man...

ricardo kuhn

Oh I get you now,,,and i totally agree with your remark, something to pay attencion for sure that i over view just because I assume was "freeride" dirtjumper fork, maybe I will weld some "solon taps" on them to avoid bad surprices.

thanks for the heads up.

some of the old BMW "airhead" feature a cable operated lever that activate a Hydrolic pump located inside the frame (under the tank) i have no idea why they did it this way, maybe because the pumps were so bulky and ugly at the time, anyway on a bicycle the problem will be backwards if you were to install a hydrolic brake, i think you will need a "Firewall" A.K.A. a place were you can locate the reservior in a fix possition, on the other hand a mecanically operated will have far less issues as long as the lever travel is compatible,,the diacompe levers i remenber were made for cantilever dutty NOT for V-brake (long cable pull) but for sure will be fun to try..

about the stocker operating the brake,,at least in my experience when i have my bike set up that way long time ago, the passanger ussually will be scare S^^Tless and will aply the brake all the time, slowing the bike, maybe i need to find a "stable" partner that will not do effords to slow down the bike,,so far tandems for me are very "autoritarian" or "dominant"

you are right certain bikes can not pull "aircraft carrior dutty", the GS's like mine work extremlly well but I try others with really ill results, to unstable, to low,,to many problems

on a side note, i saw your Avid disc project and I need to tell you that bike of yours is one of the most elegant and slender pedal machines I ever saw, the resolution on the rear is pretty much the way i want to do it,,running the caliper inside the rear triangle to leave alone the space for the rack, my idea was simpler just to run a small plate with the holes just drill to hold the caliperor or a little tube with two bores for the same porpuse but i was never really convince,, now after seeing the way you guys accomplish it, I have a few more ideas to make it very nice , pretty and still,,for that i will show you later.

thanks again for the great advice, for sure you guys know your stuff (not to mension the Impecable taste), i be glad to amusse you with my "silly" aproaches.

ricardo kuhn

thanks as longest I don't kill my self and more important my "partner in crime" I be happy to improve and thinker with the new red toy..
funny for a long time i was super focus on my motorcycles and somehow my pasion for bicycles was "dormant" (Sleepy) i quess i became lassy or something, but this days everything is kind of back to normal,,pedaling is so wonderful, specially with people you like,for example this afternoon dinner dates on the bike are the most peaceful and enjoable things.

oh if you never need lights,that stadium III I have is Incredible, very powerful and extremlly nice light spread.

LV2TNDM

Ricardo is the only mechanic I know who regularly gets showered with home-made baking from his customers. Not only is he a great mechanic, he cares (a bit too much) about the bikes he fixes!
Love the pics of the IBIS!
Did you get the PM I just sent? Not sure if it went through.
-K

ricardo kuhn

Oh Oh somebody that remenber those long gone days
Nope,send it again....
but thanks for the complemens,,even if my search for perfection somehow i find it more of a Illness that a asset.

on a side note,,many years ago when I was aplying to work at City cycle in san francisco the owner ask me this tricky question at the interview..
"so how long will take to build a bike for your girlfriend" my answers was ...EXACTLLY the same time that will take me to build ANY other bike..
needless to say I go the job, but the again the
words is "Good enogh" is never sufficient and I end up trying to perfect everything even if the materials & components don't have the quality to take the "Magic" A.K.A. Pure hard work..

another famous quote from the day I was "let go" from a "fuffu shop" (thanks to my answer)
"I much rather try to make a $300 bike work like a $3000 bike,, that let out the door a $3000 dollar bike that work like a $300 bike" when no wonder i get fire.


sorry for the side note,,now lets go back to regular programing.

ricardo kuhn

Finally I got all the components to finish my 20MM fork project

*The fork is a "FUNN" 20MM with brake post welded in the back of the fork to run V-brakes.

*the Hub is a 36 hole Big-Um with a 20MM axle.

*Headset King steel head with a 20Mm insertion.

*the rim a Atomlab Trailpimp no eyelets but i install brass washers at the nipples to reduce friction.

*The spokes,,,triple butted DT spokes(Alpine i think is their name) with aluminum nipples(No never have failures on the many wheels I build with them) lace 4 cross.

*the tyre a Michelin 2,7'' but i can fit 3,2" if i ever want to.

*the V-brakes are old style XT calipers (I can not find anymore XTR's for cheap) no fork brace so far but not as necesary as if you run the brakes forward (convensional way)

*The disc brake is a HOpe Enduro(four piston caliper) with a C-2 type lever running on a close sistem with a 205MM Hope rotor (5 Bolt rotor).

anyway here are the first pictures of the new fork and wheel,, the bike feels amazing, no fork flex and for sure no Quick release failures or fears but still resilient and some how cushion (maybe the lace pattern and the big tyre)
the only and very ovius problem so far is that the standover height was reduce drastically( about 3 inches from the stock fork) in fact with my almost 34' legs i'm touching the toptube when I stand on the groung for my good luck i'm kind of use to it do to my motorcycle riding.

anyway enjoy,,,If you like Monster Bikes that is..






notice the second "stem" to mount the light (got the idea from a link on this forum..


the ground clearance is impresive but i still mount the bash guards just in case, not to mension they help to protect your pants if you go on a leasure ride.


i still need to finish the rear Disc brake caliper mount and then the project will be kind of "Complete",,well until some other crazy idea comes around..


the rear hub is also a Hope Big-Um and so far is being trouble free even if is being subjected to incredibly step high climps, will see when it fails.

TandemGeek

Does FUNN explain why they favor that orientation of the I.S. disc tabs vs what I'll call the more conventional one? I only ask as I've recently started to notice several different installations where the caliper is sitting well back of the fork arm.



Here's how our model 8 (203mm) Hope Enduro mounts up on the fork of our Ventana, which is what I'm used to seeing:

ricardo kuhn

you know mister Geek I wonder about that method my self,, to me makes a lot more sense to have the caliper as close and high as you possibly can,to avoid a variaty of reasons like.

* posibility of a rupture or failure (at least fatigue) at the Fork brake mounts do to the execive distance and leverage induce by the brake caliper.
*Flexivility of the mounts.
*possible incompatibility with Bike racks
*calipers getting scratch and damage when the wheels is of the bike with the ground.
*Caliper getting damage if you crash do to the unprotected location when the bike is in use.
*cable rupture do to a branch or other object.
*issues with saddebags (front mounted fork racks) well that is not really a issue since they are not really intended to be used at the same time, exept for the fact i want to install my front Bruce Gordon at my forks.

sadlly i have many reasons why not and almost none in favor except maybe a more flexible and compatible sistem since a lot of companies offer diferent size rotors to update the 165mm type (little ones)

one thing I can tell you my other 5 current suspension forks feature the same "Low and far back" style than the FUNN fork.