'tis not I. This Brucey does not appear on youtube (not unless someone filmed me falling off and didn't tell me... ).
rohloff hubs. i know nothing. why so expensive?
FWIW I think Rohloff are 'expensive' because they are made in small quantities by people who are paid decent wages, and they have a decent warranty. I wouldn't like to make one for the price.....
i ride fixed gear alot but have considered hub gears just to have a go at them for commuting / winter miles. i doubt that a rohloff is a good introduction to such so what would you recommend? some SA hub or other?
because they are inexpensive, readily available, work OK, and will usually slip into a 120-126mm frame that would otherwise accept a fixed gear, I'd suggest an SA hub.
Some (of the many) choices;
AW; 33% increase, 3s with direct middle gear. New and old (used) versions available, which are different.
AM; obsolete old hub but has much closer ratios than the AW. You will struggle to find one that will space out to over 120mm
FW; obsolete hub with slightly wider range than AW but also with closer spaced gears. 3rd is direct drive, which is very sensible.
The FW is a very interesting hub; it can be converted to 5s (leaving 3rd as direct, so one more high gear) and I think it can also be converted to 3s fixed, with direct drive 3rd.
I do a lot of miles on a 5s converted FW.
Some of the above internals fit into other shells (allowing you to source a 36h shell for an older hub); if not you may have to use a 40h shell with an older hubinternal. This is no big deal because it isn't difficult to build a 32h rim onto a 40h shell. Using an SA hub adds between 1.5 and 2 lbs to a typical bike if you convert from singlespeed/fixed.
Any of these hubs can be viewed as 'like riding a singlespeed (or fixed), but with some extra gears for when you need them'. However there is a little culture shock; there is a lot of lash in some of the gears, which some people never get used to.
SA make a 3s fixed hub at present and it too is in essence a modified 5s hub. However if you can't bear your fixed gear chain to be slack, you won't like the SA 'fixed' hubs; they always have a little lash in them, even in the direct drive gear.
I plan to do a fixed conversion to an FW hub and I hope that there will be minimal lash in 'direct' with the scheme I have in mind. The two low gears will have lash, but I think this is unavoidable.
As I understand it, most of the guts in the FM & S5 are the same, and one can be converted into the other if one has the right bits. Presumably the FM & FC could also be turned into 5 speeds but the jump into top gear might be a bit big.
What I'm wondering is what's inside the S3X hub, and whether an S3X plus an FC can effectively yield an ASC. From the old SA manuals it appears that there are only a few crucial parts that differ between the FC & ASC, but they are unique to the ASC. Since the S3X is also a 3 speed fixed hub perhaps it contains similar parts (one of which is the hub shell).
IMHO the ratios in the S3X are too far apart, hence my interest; I have a couple of old FCs parts could be scrounged from.
That is an interesting idea, but I don't think it will work. The FM and S5 are completely different. The S5 and FW are closely related, but not the FM.
The current S3X is based around a more modern single-toggle NIG-type 5s hub with stepped planet gears and a single ring gear. All these hubs are fundamentally spaced differently inside (the NIG style clutch assembly is longer, and the ring gear is pushed to the left more), which means that, whilst you can swap an entire internal in some cases, very few of the major parts will swap between the NIG-based hubs and the older non-NIG based hubs. This means that the clutch from a modern NIG-based hub almost certainly won't (not without major surgery) go into an older gear (of any kind); there most likely won't be room for it.
Also the very close-spaced ratios in the 1950's four-speeds like the FC and FM are obtained by having two separate gear trains, (each with a separate ring gear) in the hub. The closest gear ratios are (in essence) generated by taking the difference between two more widely spaced ratios. The second ring gear is built into the hubshell, and only gears with a similar second gear train can be expected to work in hubshells of that type. This means that whilst you can swap internals around between (say) an FM and an a FC, that whole series of hubs is quite distinct and separate from all the other (single ring gear) hubs.
BTW I recently discussed the workings of the old ASC with a chap who had used (and saved) many of them and he maintained that although 'fixed' there was invariably a lot of lash in some gears. I can see exactly how this would happen, because the second gear train in the FM and FC hubs always had rather slack clearances in it. This means that even if you installed a good (lash-free) sliding clutch in the right side of an FC hub, I think you would be left with a lot of lash in some of the gears.
My idea of converting an FW to 3s fixed also won't give a 'perfect' hub (not in its simplest form) but it ought to give very little lash in the most used direct gear. The reduction gears would have a fair amount of lash in them, mostly from where the sliding clutch bears against the ring gear part. A modified ring gear assy (with closer-spaced splines internally) could help rectify that, at the expense of shift quality, but that would be a lot of work.
I guess this discussion ought to be split off into another thread...?
I didn't know the S3X was fundamentally different. So much for that idea.
IIRC, there were only three or four major differences between the FC and ASC, and the FC and FM only differ by having different sized sun wheels and planet pinions. That's not going to help if the S3X is completely incompatible...
Brucey wrote:because they are inexpensive, readily available, work OK, and will usually slip into a 120-126mm frame that would otherwise accept a fixed gear, I'd suggest an SA hub.
Some (of the many) choices;
AW; 33% increase, 3s with direct middle gear. New and old (used) versions available, which are different.
AM; obsolete old hub but has much closer ratios than the AW. You will struggle to find one that will space out to over 120mm
FW; obsolete hub with slightly wider range than AW but also with closer spaced gears. 3rd is direct drive, which is very sensible.
The FW is a very interesting hub; it can be converted to 5s (leaving 3rd as direct, so one more high gear) and I think it can also be converted to 3s fixed, with direct drive 3rd.
I do a lot of miles on a 5s converted FW.
Some of the above internals fit into other shells (allowing you to source a 36h shell for an older hub); if not you may have to use a 40h shell with an older hubinternal. This is no big deal because it isn't difficult to build a 32h rim onto a 40h shell. Using an SA hub adds between 1.5 and 2 lbs to a typical bike if you convert from singlespeed/fixed.
Any of these hubs can be viewed as 'like riding a singlespeed (or fixed), but with some extra gears for when you need them'. However there is a little culture shock; there is a lot of lash in some of the gears, which some people never get used to.
SA make a 3s fixed hub at present and it too is in essence a modified 5s hub. However if you can't bear your fixed gear chain to be slack, you won't like the SA 'fixed' hubs; they always have a little lash in them, even in the direct drive gear.
I plan to do a fixed conversion to an FW hub and I hope that there will be minimal lash in 'direct' with the scheme I have in mind. The two low gears will have lash, but I think this is unavoidable.
cheers
What is lash please?
Entertainer, juvenile, curmudgeon, PoB, 30120 Cycling-of course, but it is far better on a Gillott We love safety cameras, we hate bullies
on a fixed gear it means that the cranks will rotate back and forth a small distance independent of the wheel. On a geared bike it means that the cranks will rotate a small distance forwards before the drive is taken up.
To give you an idea, a conventional shimano freehub has ~18 teeth in it, meaning that the sprocket (and the crank, approximately, in a low gear) may rotate 20 degrees before drive is taken up.
By contrast some older SA hubs have a 10T ratchet for low gear, plus there is
a) the gear ratio to take into account, giving 36 degrees x 1.33 = 48 degrees and b) backlash between the driver and the ring gear (up to ~45 degrees)
giving a total lash of ~90 degrees on the sprocket (or about 1/3 of that at the crank with a typical input ratio and a 27" wheel) before drive is definitely taken up. Many IGHs have a larger lash in them in the lower gears but few have it to the same extent as in older SA hubs.
If you have ridden with this for decades you get used to it, but if not, it can feel terrible to start with. A side effect of getting used to it is that you become much, much kinder to any freewheel, tending not to slam against the pedals and potentially damage the freewheel mechanism.
).
