Just a quick post - this is new to me so I guess may be of interest to others..
Shimano have just released a 135mm width incarnation of their Microspline hub (previous hubs have been 142mm or 148mm Boost widths)
So this means we have the "opportunity" to put Shimano's monster 10-52 tooth 12 speed Deore cassette on our existing touring or trekking bikes
Hyperglide hubs still being offered at the moment of course .. but I expect to see a lot of them disappear over time ... maybe this is the time to start hoarding (not that I need the excuse )
which does rely on 5/32" ball bearings for the hub to turn on.
I have seen off-brand cup and cone hubs with a standard freehub body and a through axle, and these sometimes manage ball bearings as large as 3/16" (ooooh!) however to do this requires that the cones are barely recognisable as cones, and protrude only slightly above the axle; the slightest wear causes havoc.
The main benefit of the whole through-axle/micropline arrangement is that you get to use a stiffer rear axle (for better strength and consistency of disc brake alignment) and a 10T sprocket. A 10T sprocket is (IMHO) just for specmanship, not for actually using.
So if I have understood this correctly Shimano are moving away from having the main axle bearings at the right hand end of the axle .. as in Hyperglide and instead relying on the axle strength - a bit like old freewheels but with a stiffer axle ?
zenitb wrote: Have I got the bearing position right on this ?
not if FH-MT401 is a variation on FH-MT400, otherwise yes.
[edit; on shimano's website it describes these hubs as having 'radial cartridge bearings for the first time by shimano' so they are indeed like other manufacturer's hubs, no longer using cup and cone bearings then. Actually the RH hub bearing is slightly further to the left than you have drawn it; the pawls occupy that space.]
zenitb wrote: Have I got the bearing position right on this ?
not if FH-MT401 is a variation on FH-MT400, otherwise yes.
[edit; on shimano's website it describes these hubs as having 'radial cartridge bearings for the first time by shimano' so they are indeed like other manufacturer's hubs, no longer using cup and cone bearings then. Actually the RH hub bearing is slightly further to the left than you have drawn it; the pawls occupy that space.]
zenitb wrote: Have I got the bearing position right on this ?
not if FH-MT401 is a variation on FH-MT400, otherwise yes.
[edit; on shimano's website it describes these hubs as having 'radial cartridge bearings for the first time by shimano' so they are indeed like other manufacturer's hubs, no longer using cup and cone bearings then. Actually the RH hub bearing is slightly further to the left than you have drawn it; the pawls occupy that space.]
cheers
Are there no bearings in the freehub body? Construction looks quite similar to my Hope pro4 hubs where there are 2 cartridge bearings in the hub & 2 in the freehub with both mounted on the axle tube. The axle in the dismantled view in the earlier picture looks like it has 2 slight "wear" marks on the axle tube where the freehub would sit.
Former member of the Cult of the Polystyrene Head Carbuncle.
Hyperglide hubs still being offered at the moment of course .. but I expect to see a lot of them disappear over time/
I doubt that. There are a heck of a lot of HG wheels out there and even if Shimano aren’t making others will. And even then, Shimano make a lot of <12sp kit themselves, and that’s not going to change soon.
RickH wrote: Are there no bearings in the freehub body?
yes of course. OP is, I think, considering the hubshell/axle loadings from a touring perspective.
In such designs the entire load on the rear wheel is supported by the RH hubshell bearing and it is applied to the (almost exact) centre of the rear axle, which is least well able to bear it. The LH hubshell bearing is more or less just there to deal with lateral loadings. It is a design that works OK on MTBs, but MTBs are not touring bikes.
RickH wrote: Are there no bearings in the freehub body?
yes of course. OP is, I think, considering the hubshell/axle loadings from a touring perspective.
Yes, that was exactly what I was concerned about ... hence only showing the main load bearing bearings
Brucey wrote:In such designs the entire load on the rear wheel is supported by the RH hubshell bearing and it is applied to the (almost exact) centre of the rear axle, which is least well able to bear it. The LH hubshell bearing is more or less just there to deal with lateral loadings. It is a design that works OK on MTBs, but MTBs are not touring bikes. cheers
.. and this is my concern as well. Hyperglide hubs with well supported steel axles and large cup and cone bearings have been the staple of my bike fleet for the last 30 years (after bad experiences with the previous bent/broken axle prone freewheel setup the industry used). Now we have more stressed (but admittedly thicker) rear axles and sealed bearings coming in .. with matching cassettes designed for 1x geartrains only. I am surprised Shimano have gone this route.. and a bit nervous that the massively successful Hyperglide system will be relegated to the cheaper sub-Deore groupsets only. Watch this space I guess..
Diagram modified in line with Brucey's comments ..
shimano 12s road doesn't exist yet; it is still only a rumour. Almost pointless trying to compare XT with ultegra; they don't fit in the same frames as one another, so unless modified you don't really have a choice in any one bike.
re hubs; thinking about it, White Industries rate their rear hubs for touring/tandem use. They use the same layout of bearings and a 17mm dia hollow steel axle. They use the same layout in MTB hubs too. I have not heard of axle problems with these hubs, but having said that maybe they are so niche (in tandem/loaded touring use) that there just are not a lot out there which have been given the treatment.
I note that in some applications steel axles may not have a fatigue limit in contrast to aluminium axles.
One thing I would say is that the cartridge bearings used in the W.I. hubs are the same as have been used in various ST bottom brackets over the years, 17mm ID. I have found that they are of marginal strength in BB use; the slightest deficiency in lubrication or other operating conditions and they soon fail.
The thing is that people use MTB hubs for touring, and MTBs for touring so an MTB is often a touring bike.
This is all rather confusing... And rather than the range and availability of hubs that are good for touring getting wider, it is getting narrower and the potential for choosing an unsuitable hub/axle 'standard' is getting greater.
And loads of hubs and (frame adapters) use interchangeable end caps that make me wonder how durable they will be over time and distance.
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