The pre-disc brake KH frames had 22 mm wide bearing housings.
The frames with the disc brake mount have 20 mm wide bearing housings.
The disc brake setup is designed for use with 6 mm spacers. With a 6 mm spacer the disc caliper should be approximately centered in its lateral adjustment and there should be about 1.5 mm clearance between the rotor bolt heads and the bearing housing.
That means that there would be negative 0.5 mm clearance to the old bearing housings, so yes they would need grinding to work.
Alternatively, 8 mm spacers would give enough clearance for both old and new frames although they move the cranks outwards on the splines. I have used this on prototype setups that had 22 mm bearing housings and it worked, although it’s not something I would officially recommend.
cant comment on spacers as Im using a schlumpf hub with no spacers.
and with this set up I had to file my 2011 bearing housing inside and outside (quite a lot).
my 2012 bearing housing, took a bit of messing around to get working, I did file some metal away from the outside bearing housing
as well as countersinking the rotor holes and using countersunk bolts.
as far as the alignment of the disc brake tab. no problems at all.
no shims needed
I have rarely had any big issues with rotor bolts scrapping my 2012 Kh frames. I dont think i will ever mess with or take material from my Rotor…
I found a few different branded bolts have different depth profile bolt heads!
Some cleared some i reduced the head if it was viable and worthwhile ( My fav Ti ones i ground back, extra bonus they are even lighter still now)
Caliper alignment i have not yet in 4 Kh uni builds had any problems needing to space the disc, brake adaptors or caliper.
With my Schlumpf recently i decided to use crank spacers to maintain the disc bolt clearance and keep the crank bolt under tension. I felt it would be too loose and using the 6mm spacer only extended the crank arm around 2mm further outwards on the spline. I am happy with how it worked out.
I believe Kris’s efforts in designing the 2012 frames and OBD arrangement are as close to precise as possible. Spirit cranks are Brilliant
Just one mention. The new Kh Unis. They do not come with 6mm spacers for the cranks. Only spacers between the hub flanges and bearings themselves.
My old 36er came with one 6mm and one 8mm on the crank sides now the new ones i assuming rely on the crank to pull up along the tappered isis spline but with a disc fitted can need the spacer as mentioned by Ben and Kris
I use Shimano XT (alloy carrier) and Avid HS1 discs currently
If using alloy carrier discs they usually are thicker than all stainless rotors but the XT does work and have plently of clearance. Be sure to have the rotor rotating the correct direction though. Being and outboard rotor compared to a inboard bike situation your alloy carrier rotor will be facing into the wheel. With the Back or Ugly side of the rotor facing out towards the crank!!! But i dont see past the Spirits, They are Beautiful
That’s great - thanks for all the details.
Re the spacers: all KH unis should come with spacers between the bearing and cranks. If you didn’t get them, they were missing. Without disc brakes you can get away without them but for precise disc brake installation they really are needed. There was a period some years ago when KH cranks came with 8 mm spacers, but that should not be the case now.
Wow hi Kris, thank you for for posting! absolute pleasure to conversation with you.
Re: crank spacers. In the past 10 months approx i have purchased 2012 KH26 and a 2012 KH29 (disc frame, spirit model for those unaware) and both Unis only have been supplied with spacers fitted for in the frame between the hub and bearing. None on either for the crank to bearing sides…
Perhaps i should mention this to Peter at Municycle.com.au and he can follow this up. Up until i got an older KH i hadnt seen spacers on the crank side. As most other brands dont and rely on the tapered spline to pull cranks up.
I did when building my Guni use a 6mm spacer on the disc side to meet tensions and rotor bolt clearace but wasnt sure if it was the right thing to do or recommended. I when with the spacer seeing no ill affect could really come from its use given its only 6mm wide.
Little disappointed i needed to buy my $2.50AU spacers now. End of the day i am more than happy with my KH unis and the disc setups. I will soon have my 3rd KH.
Great topic raised Ben!
Ps- i wonder if Kris will comment on the 700c Guni i sported few months back. Far as i could tell, first of its kind and only one in exsistance??
With my Schlumpf (#641) and a disc tab 2013 (or maybe late 2012) KH frame there was a LOT of filing that needed done. To get the disc adjusted so it didn’t drag required filing the adapter AND the tab on the frame- removing several mm of material between the two. Both bearing housings required filing on both inside and outside too. 30N-m and lots of loctite were used so there wasn’t excessive force applied in the first place.
Lots and lots of filing was involved. Now that it’s done, it’s been stable and fine, but it wasn’t a project for the timid.
wow you had troubles getting things to clear hey?! I feel sorry to hear that. It can be frustrating when things dont go to plan
Can i ask what brand brake caliper, disc and brake adapter you used?
I did grind back and mill out a clarks adapter for a 203mm XT rotor once. i had to grind so much material off it to make it work and clear things. I took a photo and was going to keep that episode to myself… i still laugh every time i see it… i had the disc ( alloy carrier, stainless brake surface ) facing the wrong way and it was rotating the wrong direction and they have offset disc bolt surface!!! which is great for the design but for a uni with spirits easily put on a** about face :o silly me
I will have 2 when they are produced and available. When ever that is … soon one can only hope at this stage.
Going to sell a bike to fund them i think is a fair thing to do
Maybe soon as Ben buys a 1: 1.5 to support schlumpf they will announce a 1:1.3… i know it sounds mean but usually how the world works with many things. Wonder if they would supply a kit for 1.5 to go 1.3?? obviously this will void warranty if not done by the factory
I hate spending money, but I’ll be one of the first to buy a 1:1.3 hub as soon as I have the money and they become available. I’d love one for a 29er or 700c road machine. (The perfect unicycle as far as I’m concerned, excellent climbing and still decently fast on flats.)
Maybe if enough people chime in here, someone will notice? (Kris?)
But as the song goes, “You can’t always get what you want…”
I’d probably sell a kidney to fund it if I could find a willing enough buyer.
6mm spacer on my Schlumpf muni disc side gave it the rotor bolt clearance no issues. With spirits that is. i could understand other cranks might like a longer axle. Current schlumpf axle yes wont be tight if using a spacer and expecting to have bolt clearance without grinding material off somewhere and alot.
Am i thinking that a the newer schumpf with longer axle wont need spacers when running OBD
Um whats with Kris’s website at the moment? Making a new one or…???
Brake: Shimano SLX and Tektro Auriga were tried. Adapter is Avid (I believe). It looked the same as a Shimano I used before. Disc 160mm- both the Shimano and Tektro look about the same. 160mm.
I really overall like the 1:1.5. That gearing is necessary to go as fast as possible on a 36 and works well on the G26 too. 1:1.3 would be of little interest to me on the 36 for sure. It would have a use on a 29 (for me) for offroad, but that would be about it. The 26 with 1.5 still has the higher gearing edge if heading to the road at all.
The Schlumpf is a great piece of machinery. With rim brakes all is good. Actually, it’s really helpful when shifting the 36 with the rim brakes to apply the brake a bit to take pressure of the mechanism for a smooth shift. This can’t be done with the disc as the disc stresses the system rather than removes pressure.
I knew the disc setup would be tricky. I didn’t want to wait over a year (if it is only that) for another generation to maybe become available. I’m not trying to say that it’s not worth it now, but it is a hassle to get the set up right at this point.
For me, having the Schlumpf by May of 2013 was worth it. After all, Unicon in 2014 is only a day’s drive away and I’ll be quite comfortable on the G26 by then. If I had waited, I may have missed the boat.
I had a great race on it a couple of weekends ago and look forward to another this weekend. High gear helps to level the playing field when bikes start to coast and shift.