Hope Big 'Un 20mm QR Axle...Or Not

[Supratada]

Thread resurrection!
A follow up question regarding the 20mm bolt through axles on me San An. Mine is as the silver hub in the earlier picture, the one with the red hub in also.

My question is ... Is it correct that the end pieces, the "top hats" are loose and will fall off as one pulls the axle out (if you don't catch them as you do it)?

It seems a fussy way of setting up a hub/axle combo to me. The bearings are press fitted in the hub body and the internal spacer is held in place so I have to thread axle in one end of fork, make sure I have correct length top hat on the non-rotor side, push axle through and then carefully slot rotor side top hat in place before finally pushing axle all the way into other fork leg.
Is this like a "downhill" thing where if you puncture, the race is over for you and you're not going to bother repairing it in situ?

 

[Supratada]

Oh, I should add that the caps I had had an inner sleeve but the only bearings I found that fitted the newer hub with a 20mm axle, wouldn't allow the inner sleeve to fit through, so I ground it off. However, the various aftermarket cups I've seen also don't have that inner sleeve.

 

[dyna-ti]

Not sure what help can offer but here goes.....

Big un isnt one of the hubs ive had much to do with.

The earliest i think had a set of double bearings attached to each cup. I had some of them, think pictured in the timeline thread. That might have been the hanebrink one, so the bearing seats might have been different, deeper to allow a 2nd bearing so 4 on the front, 2 each side.

Other than that the standard way is circlip as with the bulb and the modern hubs. I cant remember seeing a groove on the big un to accept the clips, so it could well be you partly slide the axle through to catch the first spacer, then add the wheel, then fiddle the 2nd spacer in and wiggle the axle through that.
Rears used to be something similar I seem to mind from the early one. Boxxer i think is your best source of info, he was very much into the DH bitd. Knows a lot about the odd bits. Wasnt my thing but i do remember folk moaning the fiddly rear spacers were fiddly to fit. So might just be they sit and are held firm by pressure alone.

Sorry if its not much help, but it might get the thread started.


I dont know why but Hope seem not to have the big un in their tech spec section. Hell of a hub, can think why its not included in there.




Ive a single big spacer, must be for the big un.
It also had originally a lip for a bearing that was ground off. I got it from a chap who worked at hope for many years, part of other bits, and I get the impression as it was from his stuff and the ground off bit that Hope started off the bearings attached, but then changed the design so the bearings were in the hub and just ground off the lip, so it sat against, and was held by pressure. Because I also cannot see any other way of holding it in. Must have been loose.

When you are able to place the hubs next to eachother and have an idea of which hub features seems to be reused down the line ?, like the fatso spacers that slide down intot he bearing is the system we use now, but they came up with that system in 1994 or so. And there seems to be a lot of Hope bits like that. Older designs making their way into the modern hubs.
Nice to see we're back to large flange Hope hubs. Again we started wide, then went narrow, and are back to large. In fact you could mistake their early hubs for pro4's.

 

[Timoth27]

Re:

This is my experience. I have a 97 bigun which I now believe to be an early one (Bean can) which started as qr and in the early 2000’s I bought a readily available (at the time) 20mm conversation kit which consisted of 2 end caps, 2 new (different to original) bearings and a Center tube. The end caps where just like the current 20mm ones (only without the spring clip things) this meant that when you took out the wheel you had to catch the end caps as they where loose, never bothered me as didn’t really take the wheel out that often.

I’ve since also got a newer bean can one and a mk2 (skinnier center) both of which have a different center tube And different bearings, which allows a different end cap that looks a bit like the current qr/12mm ones.

I think what you have done is cut down a later end cap to make it fit an early hub. I’ll try and take some pics of what I have later as my description skills are a but lacking lol.

 

[dyna-ti]

Can you see it in here.

Note -I no longer have many of these.

 

[Supratada]

Well, the caps I have as they started out are nothing like any of those. Mine where closest to the black one top centre left, 20mm by 21 but they had an inner projecting "sleeve" that went inside the bearing, I think. Once ground off, they were pretty much like that black one, but in two lengths for disc position tuning.

 

[Supratada]

In fact you can see one of them here, up at the right, next to the 20mm axle standing on end.
They came from the faded hub which has a bigger hole, but I put them in the left hand hub which meant the bearing races would have been impossibly thin to allow the inner sleeve to press fit into the inner face of the bearing race.

Effectively, I've answered my question now. The outer cups fall off because I've frankensteined parts from a bigger older hub into a newer one. If I'd used the faded one, the front wheel would mount onto the thru-axle with no messing about, but .. .faded.

 

[Timoth27]

Re:

So here’s what I have.

97 bigun with qr axle.



20mm bigun like the red one above



20mm end caps for silver hub above, these are loose.



Mk2



End caps for mk2



Red and silver hubs at the top use 6804 bearings (32 x 20 x 7)

Red mk2 uses 6805 (25 x 37 x 7)

Regards the length of the end caps hope supplied me with this info a while ago, several of which I Managed to confirm by checking on wheels I have.

20mm hope spacers measurements
Disc/Non Disc
Big un pre 05
21mm/19mm
Big Un 05-On
20mm/18mm
Bulb Splined
13.5mm/13.5mm
Bulb 6 bolt
19mm/13.5mm
Pro 2/ EVO/ Pro 4
19mm/19mm

Hope that makes sense

Tim

 

[Supratada]

Yeah. The mk2 has a wider bearing with a 25mm ID to take the caps plus a 20mm axle.
Makes sense now as the later model would need to accommodate the “new” 20mm thru axle craze. I suppose I could have waited till the right hub came along but I’d still have an unfinished bike now.
‘Course, if you ever want to sell that hub there...

 

[BAScorsa1988]

Can anyone confirm the measurements of the MK1 hope spacer for the Big un? Is it 21mm outside diameter and 19mm long?