Need Square drive or ISIS BB and crankset [UNI-CAM]

IWANTBLUEIWANTBLUE Posts: 134
edited March 2016 in Workshop
Hi, Bit of a strange request and please redirect me if I'm in the wrong place, but I am hoping someone can point me to the right item to enable me to change my hollowtech II Shimano 105 Crank set and BB for a square drive or ISIS equivalent.

The reason for this si that I want to turn my Giant TCX1 CX Bike into a physiotherapy aid for my knees by fixing it to a turbo. (yet to buy this also)

Very Long story Short I need 2 x knee joints but am told I'm too young, so the option suggested and embarked on is High tibial Osteotomy (cut the bone below the knee, open out a wedge shape to re-align the bone {and hence the angle of loadbearing in the kneejoint} This wedge is fixed with a titanium Plate and packed with Bonelike material to assist fusion.

This operation went well, and 10 weeks later I was walking 1/2 mile without crutches, stairs etc etc.. then two infections a 5 day and 3 week Hospital stay for IV antibiotics, 2 emergency scrape out operations and 4 months of Daily Home IV antibiotics has left me with a leg that doesn't bend and straighten properly :(

There is a Physio therapy aid called a UNI-CAM on an exercise bike and a home version that I propose to purchase to allow reduced bend knees (and hips and ankles incidentally) to 'cycle' just the same as the 'good side', effectively using a pivot and 2 levers this allows the turning circle to be reduced to virtually nothing on the affected side.

This kit will only fit to a square drive or an isis fitting hence the requirement to change the BB and crank set.

do I just measure the BB width and bearing size and look for an equivalent size in square drive for instance or is it not as simple as that?

Thanks for any assistance you can offer...

Nick

Posts

  • nicklousenicklouse Posts: 82,097 Lives Here
    you need to get the correct length axel for the cranks you get.

    but for your frame measure the width of the shell (should be 68mm) that will give you one of the measurements that you need for the BB the axel length will depend on the cranks.

    that can be found in the makers specs.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Monty DogMonty Dog Posts: 20,614
    You'll have more options with a square taper BB but you really need to know what model of crank / length of spindle you need as they go from 103mm to 120mm+
    ISIS only comes in 3 lengths - 108, 113 and 118 for road double, road triple and MTB. It was superceded by external bearing designs over 10 years ago and it was an inherently weak design due to tiny bearings which don't last very long.
    In all cases you'll need a 68mm BSA/English threaded BB to fit your Giant frame.
    Make mine an Italian, with Campagnolo on the side..
  • IWANTBLUEIWANTBLUE Posts: 134
    nicklouse wrote:
    you need to get the correct length axel for the cranks you get.

    but for your frame measure the width of the shell (should be 68mm) that will give you one of the measurements that you need for the BB the axel length will depend on the cranks.

    that can be found in the makers specs.
    Thanks Nick, I've spoken again to the designer/supplier and he has said that square drive would be best so as Monty Dog suggests below I now know I need a square drive so need to find the cranks first it seems

    Monty Dog wrote:
    You'll have more options with a square taper BB but you really need to know what model of crank / length of spindle you need as they go from 103mm to 120mm+
    ISIS only comes in 3 lengths - 108, 113 and 118 for road double, road triple and MTB. It was superceded by external bearing designs over 10 years ago and it was an inherently weak design due to tiny bearings which don't last very long.
    In all cases you'll need a 68mm BSA/English threaded BB to fit your Giant frame.

    Thanks for the info Monty Dog so We have narrowed it down to needing a 68mm English Bottom bracket for a square drive , I will be running a road double so so will need something in the region of 108mm depending/determined by the exact crank I purchase so i need to pick a square drive crank set first of all which will decide the spindle lenngth ?

    from what I can gather the system works by effectively bolting a second crank arm plate on top or the existing arm, but this plate has new spindle threads(pedal threads if you will) along its length where a new 'piviot point bearing' threads in , followed by another crank arm similarly threaded so that it can be placed in a range of positions and the pedal threaded into one of the other holes, again adjustable.

    These holes effectively give the adjustment from 0 degrees movement up to full leg action in approx 10 degree increments.

    I gather its the fitment of the first crank arm of the unit that means it couldn't be fitted to modern cranks as it looks to rely on some sort of fitment inline with the BB spindle.

    I don't have it yet as its £222 each side and I need to price the rest of the parts to know if its worth converting, so thankyou to you both for assistance so far I just need to try and find some nice double cranks that I'll be happy with when I remove the unit, or just cheap as I can find and swap back I guess... :roll: :mrgreen:
  • IWANTBLUEIWANTBLUE Posts: 134
    Well I thought I was sorted.....

    In the absence of the bike in hand I wemt with MontyDogs suggestion that English threaded would be the way to go and as I had then chosen a vintage Campagnolo Record alloy chainset, I purchased a 102mm english threaded Chorus Bottom Bracket to suit.

    Unfortunately I had a bit of a wobble after I had ordered it worrying "what if 102mm wasn't wide enough", which led me to rack my brains for what was actually fitted and I remembered I had taken photos when I changed the crank from fsa CX set to standard 105...

    at which point I rememebered the 86al, or to be more precise the PUSHFIT FSA BB-AL86 24mm B3045

    so that's one BB I'll have to return and now to start the search again :cry:
    although I suspect this now means I'm completely scuppered :(
  • IWANTBLUEIWANTBLUE Posts: 134
    edited March 2016
    As I suspected, I seem to have drawn a blank :(

    can anyone confirm that square taper and Isis chainsets /bottom brackets never crossed over with the BB86 NOT the 68 I kept typing after reading so many BB specs I'd muddled them up..so this post is clearly irrelevent ref the items below, but any info ref "Never gonna happen greatfully received push fit frame as in my Giant TCX1?

    I'm fairly certain as I've spent a good few hours scouring the net for a glimmer of hope.

    It's the screw thread at each end of the spindle/axle that I specifically need so if there is any other weird and wonderful proprietary set up that uses screw on cranks please shout out :?:

    Thanks.

    EDIT:-I have now found a couple of 'potentials',DOUBLE EDIT< IM AN IDIOT I NEED BB86 not 68 Has anyone ever used or know someone who has used a VELO ORANGE Grand Cru Threadless Bottom Bracket ??

    http://store.velo-orange.com/index.php/components/bottom-brackets/grand-cru-threadless-bottom-brackets.html

    dsc_0005.jpg

    There is also a more local version of the same idea, but not as nicely presented, more like the mK1 version of the velo Orange part if you will at sgs cycles

    35532L107.jpg

    http://www.sjscycles.co.uk/first-threadless-68mm-sealed-bearing-bottom-bracket-prod35532/

    I'll post a seperate thread ref this part to get more exposure...[/color]

    EDITS IN RED...DOH!!!so ignore my suggestions, completely up the wrong tree :(
  • nicklousenicklouse Posts: 82,097 Lives Here
    See your other post on the same.

    Why start a new thread?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • IWANTBLUEIWANTBLUE Posts: 134
    nicklouse wrote:
    See your other post on the same.

    Why start a new thread?


    due to the specific question now I've actually found a potential BB (I havent read your answer yet ;) )

    Feel free to amalgamate/ delete as you see fit, i didn't want to break any rules, but figured anyone not intersted in my initial post might have used the Velo orange BB for repair purpouses etc... so thats 'why' but I totally get that it seems like 2 posts the same at this point. , maybe close this one Nick?

    EDIT:- In light of your reply on the other thread Nick , perhaps close that one if it's of no use....
  • IWANTBLUEIWANTBLUE Posts: 134
    I've asked Nick to close the other thread as it's become irrelevant now I've realised
    as I stated I'm an IDIOT.... I had a complete inability to 'see' the difference between 68 and 86mm, rather than 'spot the difference', conversely I gladly took this as confirmation we were on the right track...DOH!
    I am waiting to receive the Physio parts (they have been made and sent) and I have an idea that for the low speed and power output of my initial efforts, movement will probably be passive initially, I may have a way of converting my old FSA cranks to do what I need.

    I can't be certain till it gets here however but hope I just have to find my old cx cranks and i'll be good for initial work anyway.

    will update once the parts arrive, effectively there is no part available that I require :(
  • cyclecliniccycleclinic Posts: 6,858
    So its Bb86 i thought bb68 when you mailed me wasan odd standard. You cannot get bb86 to bsa thread adapters. Yoj are at a dead end for that one.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • IWANTBLUEIWANTBLUE Posts: 134
    So its Bb86 i thought bb68 when you mailed me wasan odd standard. You cannot get bb86 to bsa thread adapters. Yoj are at a dead end for that one.
    Yeah sorry for the waste of time Malcolm, as above I seem to have been struck with the idiot stick, whilst my brain has gone to mush being out of action so long I have no excuse other than reading a plethora of BB info and just plain getting my wires crossed re 6's and 8's....

    So effectively this thread might as well be closed as well now.
    I am hopeful when I receive the physio parts I can make it work with FSA chainset and the manufacturer/maker has now revealed he has fitted to 105 with some machining at extra cost :/ so at least it can be done,for extra cash, just a bit miffed I've wasted the last few days searching for something that doesn't exist when there was another undisclosed option but hey I guess I had a few days to waste, so no big deal at least it's achievable....

    Please close when viewed admin :)
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