When to expect the disc KH cranks

[danger_uni]

I was wondering about that too, before I started using the setup. It will depend on the rider but it was better than I thought I would be, because you can actually shift, in terms of clicking the button - it just won't engage. Taking the brake off for an instant will let it engage. It takes a bit of time to get used to, but it works fine.

My wife and I are going to UNICON with our baby daughter Nola so it's really more a family holiday. We'll just be there for the first half. To be honest I haven't had much time to ride in the last few weeks since Nola was born, so won't be in the greatest shape but it will still be great to see old friends and meet a bunch of people I've only yet known online.

[Nurse Ben]

That's simply not true. According to Magura themselves, an HS33 is 464g. Plenty of disc brakes weighing less than 400g - for example a Magura MT8 weighs only 310g including the disc according to exactly the same source of information (personally I have Formula R1s on my MTB which come in at under 300g, and when I get a disc brake on a uni I'll probably reuse one of my old B4SLs which I replaced with those, but which are a similar weight) . I presume that doesn't include the adapter, but then one of those is only ~20g, still making the disc brake far lighter.

I wouldn't use the mfg listed weights if I were you, instead try weighing some as I did

I'll admit that I was also suprised, but facts is facts; I even went as far as using a sharpie to write the weights on all the parts; I posted the numbers on the Oracle or Oregon thread.

I imagine you could get close with an ultralight, ultra expensive disc brake, but if you want the lightest set up, Maguras are it; unless you can rig up some cantis

Ask Bryce to chime in with some Magura weights, he probably has tons of them lying around...

[turtle]

mountainuni brake system and kh/ schlumpf hub works (of course florian doesen't recommand it).

really looking forward for stronger (kh) cranks, drops i'm coming back!

[danger_uni]

I've chatted with Florian about this. That discussion related to whether it was OK to use a spacer between the bearing and the crank.

It's really not OK. I did this on an early prototype of my system and started to have issues with the bearings. Unlike an ungeared hub the bearing lacks support on the other side so it creates lateral deformation that's not good for the bearings.

However, much of that issue had to do with Sinz cranks, not whether you need a spacer. Based on the fact that people were having spline creep issues, I suspect the Sinz cranks are 6000 series aluminum, which is softer and more prone to this. In contrast, Moment cranks are harder 7075 Al, and the new cranks (more details tomorrow...) are forged from 7050 Al, which is similar to 7075 except with slightly greater resistance to stress corrosion (fracturing). I've not experienced any issue with running this setup with the geared hub, in terms of creep on the splines.

The potential issue has more to do with the possibility of slippage of the knurled bearing. As Turtle mentioned, quite a few riders have run the crank-mount system with geared hubs with good success over more than one year of riding, including myself. But as mentioned above, it's possible, so worth noting just in case.

Kris

[Nurse Ben]

In contrast, Moment cranks are harder 7075 Al, and the new cranks (more details tomorrow...) are forged from 7050 Al, which is similar to 7075 except with slightly greater resistance to stress corrosion (fracturing).

Are you going to release pics and specs? I'm curious about the Q factor.

Hey Kris, in reference to Q factor, are the Moments and the KH hub spec'd to the "Shimano" offset, so ~150mm pedal to pedal width?

Do you still find this to be an optimal width?

The reason I'm asking is that I have been riding your set up (Moments and 100mm hub spacing) since I learned to ride, but have since added an Oregon (125mm hub) with QuAx cranks which are ~175mm in width and now I'm riding the Oregon hub on a 36er with some 175mm Try All cranks which have a more than 200mm in width.

I have not noticed any decrease in ride quality, the wider stance is more comfortable and I seem to have more stability, what I notice most is the wider stance has less seat rub/crotch abrasion.

[rob.northcott]

Originally Posted by danger_uni

The potential issue has more to do with the possibility of slippage of the knurled bearing.

Seems too obvious and I'm sure it must have been considered before, but with the potential seriousness of slippage (more so with a disc brake than with a rim brake) why rely on just a knurled bearing? Some sort of solid lug into a hole in the bearing holder cap would seem a simple solution. If the problem was compatibility with existing frames, it could still be knurled but have a hole to insert a little key piece if using the correct frame.

Rob

[aracer]

Originally Posted by Nurse Ben

I wouldn't use the mfg listed weights if I were you, instead try weighing some as I did

I have. The ones on my MTB are <300g including adapters (and everything else). Sure they're expensive, but there are plenty of disc brakes close to that weight, some far cheaper - for example a Magura MT2, with a claimed weight 120g less than an HS33 for much the same price as a Bengal. In any case, you didn't mention cost when you suggested "you are looking at 100-200gm added weight over a Magura rim brake", and I'm happy to acknowledge that a disc setup is likely to cost more in total than a rim brake, though you don't need to pay huge amounts to get a light disc brake.

I used to spend plenty of time hanging around on weight weenie MTB forums where other people weighed their parts and published the info. The argument about rim brakes being lighter than disc brakes was done long ago on there - the only rim brakes which are lighter than the lightest discs are now fancy expensive custom V brakes, standard Shimano offerings are heavier. Maguras have always been known to be heavy, and heavier than even a fairly standard disc brake - hence I don't own one to weigh, so instead I checked out what others had weighed them at http://weightweenies.starbike.com/li...type=rimbrakes - in comparison to user weights for disc brakes at http://weightweenies.starbike.com/li...ype=discbrakes However the weight for Magura rim brakes on there are rather old, hence why I was using published weights - you'll note that I'm using weights for a Magura disc brake, taken from exactly the same Magura website as I got the weight for the HS33. I can't see any reason why their claimed weights for the disc brake should be more optimistic than that for the HS33, and in any case, Magura is known to publish reliable weights (I did a bit of checking, and found some independent weights for the current gen Magura disc brakes which confirm their published specs). In order to be heavier by the amount you claim, the disc brake would have to be roughly twice the published weight!

Hence I stand by my comment that a disc brake is actually lighter than a Magura rim brake - reliable numbers supplied. I did a search on here for a post of yours where you provided weights, but all I could find was a previous post where you made a similar claim about how much heavier disc brakes are - maybe you could help me out here, as it should be easier for you to find the post where you gave the numbers, so we can work out why there's such a huge difference in our positions (here's a search for posts of yours containing the word "Magura" for example http://www.unicyclist.com/forums/sea...archid=4511574)

[DavidHood]

Originally Posted by danger_uni

I've chatted with Florian about using a spacer between the bearing and the crank. It's really not OK.

Bronson Silva also said "It's not OK" when he built my geared KH 36er. I got a Magura rim brake and I'm fine with that. I'm no engineer (The Schlumpf hub is a magic black box to me) so I figured I'd have him build as per your design. That's also why I had him use Moment cranks.

I did a side-by-side test before I sold my Nimbus {disc brake} Impulse 36er. There was very little difference between the disc brake and the rim brake. It should be noted that all my Cokering is done on rails-to-trails asphalt bike paths and rarely in the rain.

I waited a long time for UDC to release the 26" Nimbus Oracle so I could have a disc brake on my MUni. It's more of a low maintenance issue for me though I did learn (thanks Brycer) how to reassemble Maggies when UPS damaged my KH36G in transit (thanks Amy for the free replacement). It was not too awfully complicated to get them to work without rubbing.

Originally Posted by danger_uni

I've not experienced any issues running the new cranks with the geared hub, in terms of creep on the splines.

I will replace the 150/125 Moments on my geared 36er with the 137mm single hole version of your new cranks so that my FiveTen Impact size 10 shoes can reach the shifting button without needing to ride on my toes. I was accustom to spinning 125/110's on my "fixed" Impulse but geared Cokering requires more leverage. Come to think of it, I've never switched from the 150mm hole. Perhaps I should at least try the 125mm hole in 2nd gear before I place my order. I'm waiting on the the rumored lightweight 36" tire anyway. I want my LBS to replace everything at once. I'm going to insist they read the Schlumpf manual before they touch it.

Anybody want to buy an unused set of torque wrenches? My mechanical prowess is limited to tightening (with my $50 torque screwdriver) the shift buttons. I need to go to Park Tool school.

[Nurse Ben]

Hence I stand by my comment that a disc brake is actually lighter than a Magura rim brake

I no longer have Maguras and all of my disc wheels and disc brakes are mounted.

But since I did a weigh in already, and saw the numbers, you can be in denial all you want, but the disc brake is heavier whether you like it or not

If you want to make comparisons using the lightest disc brake, then you probably want to be fair and use the lightest hydraulic rim brake...

I like the disc brake two reasons:

Better function when wet
No rim rub

Otherwise, they are heavier, more expensive, more complicated, have more issues with squealing, tend to be a pita, and they pull to the side.

Last night I upgraded to organic pads on my 26 an 29 to see if I could prevent the glazed pads and the associated squeaking. I'm afraid that I will end up going to a different brake because in the past I had "squeakers" and more often than not it was the brake and not the pad.

On a bright note for UDC, their Bengal disc brake has been pretty good to date, but the white color is not for me. I went on Ebay and found a source for Bengal Helix hydraulics in different colors, blue, red, black, gold

I find the best brakes are my legs

[Smilymarco]

Right now i also have issues with my Shimano-brake + koolstop semiorganic pads... they scream like hell and the whole uni is vibrating when i pull the brake...

And the braking power is not as good as before (right now it kinda sucks...).

The issue occured after my last tour with a very long downhill-section (800 meters in attidude), whole time braking... they got freaking hot...

[danger_uni]

Hey all - more info on the new KH Spirit Disk Cranks at krisholm.com (here), and on the new forum thread.

[MuniAddict]

Originally Posted by danger_uni

Hey all - more info on the new KH Spirit Disk Cranks at krisholm.com (here), and on the new forum thread.

I'm so glad you did away with the threaded inserts! But I wish the new single hole cranks were available in 150mm size, since I have no use for dual holes on my G26er. And I'm also surprised to see that the disc brake compatible cranks are only available in the dual hole version. Do you plan to make the single hole version in 150mm, or is 137mm going to be the max?

[danger_uni]

Between the 110, 127, 137, 110/127, 110/137, 127/150, and 137/165, that's already a lot of crank models.

Adding the second hole didn't result in major "hot spots" in stress analysis, and it reduces weight. So there didn't seem to be a disadvantage to adding it to all the cranks, even for riders (including myself) that don't typically use the shorter option. The fewer models there are, the better the likelihood is that a KH dealer will actually keep them in stock. So currently I do not have plans to offer a single hole 150 in the disk version.

[MuniAddict]

Originally Posted by danger_uni

Between the 110, 127, 137, 110/127, 110/137, 127/150, and 137/165, that's already a lot of crank models.

Adding the second hole didn't result in major "hot spots" in stress analysis, and it reduces weight. So there didn't seem to be a disadvantage to adding it to all the cranks, even for riders (including myself) that don't typically use the shorter option. The fewer models there are, the better the likelihood is that a KH dealer will actually keep them in stock. So currently I do not have plans to offer a single hole 150 in the disk version.

Ok thanks for the info.

[aracer]

Originally Posted by Nurse Ben

But since I did a weigh in already, and saw the numbers, you can be in denial all you want, but the disc brake is heavier whether you like it or not

If you want to make comparisons using the lightest disc brake, then you probably want to be fair and use the lightest hydraulic rim brake...

So give me the numbers you have then - I've given you mine which clearly show that an £85 Magura disc brake is 120g lighter than an HS33. I'm not the one in denial here!

Remind me again what the lightest hydraulic rim brake is and how much it weighs (for comparison with numerous light hydraulic disc brakes - eg any 2012 Magura disc, several Formula ones and several Hope ones)?