RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
The RX-RD5 hub has been out for two or three years now and in common with its predecessors, it ain't perfect. I shall detail what I've found in later posts but first an introduction which puts it all into perspective:
Sturmey Archer filed a patent for a five speed hub gear before 1930 I think. The closely related four speed hubs went into series production in the late 1940s, and despite the fact that folk had soon worked out how to make their own 5s hub using a simple modification to the 4s, it was the mid 1960s before SA finally went public with their own 5s gear. Since then there have been many SA five speed gear models; a brief summary (off the top of my head) is as follows;
a) ~ late 1920s; SA file their first patent for a 5s gear
b) ~ 1947 to 1950; SA commence series production of FW, FG, FM, FC single toggle four speed gears.
c) ~ 1965; SA launch the SA5 five speed gear, based on FW internals but using two control rods, with the left hand control being a pushrod
d) ~ late 1970s; SA launch the SA5-1 with two (pull chain type) toggles, including aluminium shell versions
e) - 1980s; SA introduce the SA5-2 model with revisions to the LH control and (finally) a different axle assembly
f) - late 1980s. SA introduce the 'five star' hubs, the last ones with twin toggle control.
g) - early 1990s; SA introduce the 'sprinter' 5s hub, with single toggle operation and dog-locking of the sun pinions.
h) ~1997; SA launch the revised 'sprinter' 5s hub, with ball locking of the sun pinions
i) ~2002; Production resumes in Taiwan and the ball locking sprinter models are now known as X-RD5 and X-RF5
j) ~2009; a new wide range 5s hub using dog locking (again) is launched with a (W) suffix marked. Previous models are retrospectively known as (N) models, but are not marked thusly.
k) ~2016; A new model RX-RD5 and RX-RF5 etc (C50 series) is launched, claimed as 'e-bike ready' it is beefier (heavier) and uses rotary shifting with four selectable pawls (each a bit like those in an 8s hub) to lock the sun pinions plus a more traditional sliding clutch.
All these hubs have one thing in common; most bike shops know to avoid these hubs when selling used bikes and when a bike comes in for repair with a faulty hub of any of these types, they usually advise to budget for replacement of the hub with 'something else', rather than attempt a repair. It is sad really; some of these gears can be made to work reasonably well, but all of them are vulnerable to damage arising through being maladjusted, much moreso than (say) a SA 3s gear.
A full rundown of known problems would take a book but briefly (with reference to the above list);
a) although prototypes were presumably made and tested, 5s hubs were not made for sale
b) All 4s hubs have inherently weak two-part toggle assemblies and require a fair amount of force to select bottom gear, because an additional spring is compressed. FM and FC models are less strong internally than FW and FG models. Alloy hubshells are thin-walled and prone to cracking, so steel shells are a more sensible choice. Three different versions of the FM gear were made; early ones had an interrupted (slotted) dog ring in the LHS of the hub, which broke. The LH planet pinions in FM and FC gears were cantilevered and the pins were subject to premature wear.
c) The SA5 is based on the FW and ought to be a reliable gear. However the bell crank on the LH pushrod is not 100% reliable, because it is made of steel that is as strong as that used in SA track nuts, which are intended to be soft enough to fail without damaging the (much harder) axle.
d), e). A litany of faults and bad decisions; the first pull chain hubs are catastrophically unreliable because the springs are the wrong stiffnesses on the sun pinions. Having presumably forgotten what happened in the FM hub, they again use a slotted dog ring on the LHS side of the new 'alloy' hubshell. It breaks. Some genius decides to make the low gear pawl pins from some kind of steel which has all the structural integrity of cream cheese, causing really bad hub blow-ups. The hubs are marketed as being suitable for ATBs; since these hubs don't last long at all on the road, nothing could be further from the truth. Folk laugh at the horrendous 'Lego Duplo' style plastic shifters.
f) The five star hub uses cantilevered planet pins so that a really compact mechanism can be made. This makes the hub inherently weak, but this fault is masked by another, even worse one; a manufacturing flaw means that the first few thousands of hubs have sun pinions which can break, and when they break the hub can fail completely (in a hubshell-breaching, Alien 'chestburster' style). A recall is instituted but it isn't carried out fully and plenty of hubs fail prematurely. Folk are still baffled by the plastic shifter; no-one would choose to have such a thing attached to a quality bike. SA's reputation for making duff five speed hubs is fairly well cemented.
g) The 'sprinter' 5s hub is better than the outgoing five star, but not by much. Adjustment needs to be spot on to work at all and some hubs are poorly toleranced so that they basically can't ever work properly. If ridden whilst out of adjustment, which is almost unavoidable in some cases, horrible things can happen inside the hub. A new, less gash-looking, but equally flimsy plastic shifter is introduced.
h) The ball locking hub is a major improvement over the dog locking one, but weak springs together with poor lube and poor shifting technique can result in both suns being locked at times, with catastrophic results; loads can be about x5 higher than normal on the sun locking and the ball-locking mechanism is dismissed by many as being 'too weak'. The situation is not helped by many hubs being installed with inadequate no-turn washers.
i) The Taiwanese ball-locking hubs are very similar to the Nottingham built ones, but with an extra garnish of variable QA. The weak springs etc are not corrected and folk continue to have problems without knowing quite why.
j) the (W) hub uses a beefed up/modified version of the dog locking sprinter internal and for the first time in 5s production, the ratios are different to that of a modified FW hub. Only now there is no closer-middle ratios benefit to a 5s hub; the middle three ratios are little different from a 3s hub. Some problems have been solved, others introduced. For example the planet pinions no longer rotate on full bushings, and the bushings that are there are liable to be both inefficient and fast-wearing. Also they delete the cone locking washer on the RHS of the hub (a part that costs pennies), meaning that if the RH cone works loose, it winds itself into the hub and smashes it to bits. However most hubs don't last long enough for any of this this to become apparent; the new (pretty) thumbshifter sticks on downshifts and soon develops excessive backlash. The result is that following each downshift, you are likely to be between gears and this tends to smash the hub to pieces. Revised shifters are made which at least stand a slight chance of working for a year or so, but not much longer than this before the same problems crop up (the tolerances are such that if the cable is 0.8mm out of adjustment, there is likely to be a severe problem inside the hub). [ A 3s fixed gear hub (with 3rd normal = direct drive) is introduced around this time, based on a hobbled 5s (W) gear. This breaks too, and is soon discontinued.] [Also, a pretty thumbshifter (based on the one for the (W) hub, but with a red bezel) is made for the earlier sprinter hubs, which have a slightly different cable pull. It has the same problems and it breaks those hubs too.] Some (W) hubs leave the factory missing the spring inside the atlas assembly. Since the atlas assembly cannot be dismantled, and the hubs won't work without the spring fitted, there is much wailing and gnashing of teeth. The final batch of (W) five speed hubs is sold off cheap to an Indian bike manufacturer and appears on low quality bikes costing £99 retail, sold in car accessory shops; the price of the whole bike is less than the former retail cost of the (W) hub and shifter alone.
k) The RX-RD5 is launched and is claimed to be e-bike ready. However the new thumbshifter has (amazingly) the same internals as the outgoing (W) shifter, and all the same problems. At my LBS early hub failures are avoided by pre-emptive use of modified shifters. Despite this I don't hold my breath regarding hub failures.
All in all not a happy story. However I took a used FW and converted it to 5s specification (with a LH pushrod, not operated by a bellcrank) and I used it for about 80000 miles before the (even older FG specification) axle finally broke. So they can be quite reliable. However I was then caught out by the 'cream cheese pawl pins' of a later (basically similar) SA5 internal, which broke after just a few thousand miles. In the meantime I used a ball locking sprinter and a (W) hub on city/utility bikes. I quite liked the ball locking sprinter and I (more or less) worked out how to live with the (W) hub too. Amongst the local cycling fraternity I am suspected of having a strong latent masochistic streak....
More in part two.
Sturmey Archer filed a patent for a five speed hub gear before 1930 I think. The closely related four speed hubs went into series production in the late 1940s, and despite the fact that folk had soon worked out how to make their own 5s hub using a simple modification to the 4s, it was the mid 1960s before SA finally went public with their own 5s gear. Since then there have been many SA five speed gear models; a brief summary (off the top of my head) is as follows;
a) ~ late 1920s; SA file their first patent for a 5s gear
b) ~ 1947 to 1950; SA commence series production of FW, FG, FM, FC single toggle four speed gears.
c) ~ 1965; SA launch the SA5 five speed gear, based on FW internals but using two control rods, with the left hand control being a pushrod
d) ~ late 1970s; SA launch the SA5-1 with two (pull chain type) toggles, including aluminium shell versions
e) - 1980s; SA introduce the SA5-2 model with revisions to the LH control and (finally) a different axle assembly
f) - late 1980s. SA introduce the 'five star' hubs, the last ones with twin toggle control.
g) - early 1990s; SA introduce the 'sprinter' 5s hub, with single toggle operation and dog-locking of the sun pinions.
h) ~1997; SA launch the revised 'sprinter' 5s hub, with ball locking of the sun pinions
i) ~2002; Production resumes in Taiwan and the ball locking sprinter models are now known as X-RD5 and X-RF5
j) ~2009; a new wide range 5s hub using dog locking (again) is launched with a (W) suffix marked. Previous models are retrospectively known as (N) models, but are not marked thusly.
k) ~2016; A new model RX-RD5 and RX-RF5 etc (C50 series) is launched, claimed as 'e-bike ready' it is beefier (heavier) and uses rotary shifting with four selectable pawls (each a bit like those in an 8s hub) to lock the sun pinions plus a more traditional sliding clutch.
All these hubs have one thing in common; most bike shops know to avoid these hubs when selling used bikes and when a bike comes in for repair with a faulty hub of any of these types, they usually advise to budget for replacement of the hub with 'something else', rather than attempt a repair. It is sad really; some of these gears can be made to work reasonably well, but all of them are vulnerable to damage arising through being maladjusted, much moreso than (say) a SA 3s gear.
A full rundown of known problems would take a book but briefly (with reference to the above list);
a) although prototypes were presumably made and tested, 5s hubs were not made for sale
b) All 4s hubs have inherently weak two-part toggle assemblies and require a fair amount of force to select bottom gear, because an additional spring is compressed. FM and FC models are less strong internally than FW and FG models. Alloy hubshells are thin-walled and prone to cracking, so steel shells are a more sensible choice. Three different versions of the FM gear were made; early ones had an interrupted (slotted) dog ring in the LHS of the hub, which broke. The LH planet pinions in FM and FC gears were cantilevered and the pins were subject to premature wear.
c) The SA5 is based on the FW and ought to be a reliable gear. However the bell crank on the LH pushrod is not 100% reliable, because it is made of steel that is as strong as that used in SA track nuts, which are intended to be soft enough to fail without damaging the (much harder) axle.
d), e). A litany of faults and bad decisions; the first pull chain hubs are catastrophically unreliable because the springs are the wrong stiffnesses on the sun pinions. Having presumably forgotten what happened in the FM hub, they again use a slotted dog ring on the LHS side of the new 'alloy' hubshell. It breaks. Some genius decides to make the low gear pawl pins from some kind of steel which has all the structural integrity of cream cheese, causing really bad hub blow-ups. The hubs are marketed as being suitable for ATBs; since these hubs don't last long at all on the road, nothing could be further from the truth. Folk laugh at the horrendous 'Lego Duplo' style plastic shifters.
f) The five star hub uses cantilevered planet pins so that a really compact mechanism can be made. This makes the hub inherently weak, but this fault is masked by another, even worse one; a manufacturing flaw means that the first few thousands of hubs have sun pinions which can break, and when they break the hub can fail completely (in a hubshell-breaching, Alien 'chestburster' style). A recall is instituted but it isn't carried out fully and plenty of hubs fail prematurely. Folk are still baffled by the plastic shifter; no-one would choose to have such a thing attached to a quality bike. SA's reputation for making duff five speed hubs is fairly well cemented.
g) The 'sprinter' 5s hub is better than the outgoing five star, but not by much. Adjustment needs to be spot on to work at all and some hubs are poorly toleranced so that they basically can't ever work properly. If ridden whilst out of adjustment, which is almost unavoidable in some cases, horrible things can happen inside the hub. A new, less gash-looking, but equally flimsy plastic shifter is introduced.
h) The ball locking hub is a major improvement over the dog locking one, but weak springs together with poor lube and poor shifting technique can result in both suns being locked at times, with catastrophic results; loads can be about x5 higher than normal on the sun locking and the ball-locking mechanism is dismissed by many as being 'too weak'. The situation is not helped by many hubs being installed with inadequate no-turn washers.
i) The Taiwanese ball-locking hubs are very similar to the Nottingham built ones, but with an extra garnish of variable QA. The weak springs etc are not corrected and folk continue to have problems without knowing quite why.
j) the (W) hub uses a beefed up/modified version of the dog locking sprinter internal and for the first time in 5s production, the ratios are different to that of a modified FW hub. Only now there is no closer-middle ratios benefit to a 5s hub; the middle three ratios are little different from a 3s hub. Some problems have been solved, others introduced. For example the planet pinions no longer rotate on full bushings, and the bushings that are there are liable to be both inefficient and fast-wearing. Also they delete the cone locking washer on the RHS of the hub (a part that costs pennies), meaning that if the RH cone works loose, it winds itself into the hub and smashes it to bits. However most hubs don't last long enough for any of this this to become apparent; the new (pretty) thumbshifter sticks on downshifts and soon develops excessive backlash. The result is that following each downshift, you are likely to be between gears and this tends to smash the hub to pieces. Revised shifters are made which at least stand a slight chance of working for a year or so, but not much longer than this before the same problems crop up (the tolerances are such that if the cable is 0.8mm out of adjustment, there is likely to be a severe problem inside the hub). [ A 3s fixed gear hub (with 3rd normal = direct drive) is introduced around this time, based on a hobbled 5s (W) gear. This breaks too, and is soon discontinued.] [Also, a pretty thumbshifter (based on the one for the (W) hub, but with a red bezel) is made for the earlier sprinter hubs, which have a slightly different cable pull. It has the same problems and it breaks those hubs too.] Some (W) hubs leave the factory missing the spring inside the atlas assembly. Since the atlas assembly cannot be dismantled, and the hubs won't work without the spring fitted, there is much wailing and gnashing of teeth. The final batch of (W) five speed hubs is sold off cheap to an Indian bike manufacturer and appears on low quality bikes costing £99 retail, sold in car accessory shops; the price of the whole bike is less than the former retail cost of the (W) hub and shifter alone.
k) The RX-RD5 is launched and is claimed to be e-bike ready. However the new thumbshifter has (amazingly) the same internals as the outgoing (W) shifter, and all the same problems. At my LBS early hub failures are avoided by pre-emptive use of modified shifters. Despite this I don't hold my breath regarding hub failures.
All in all not a happy story. However I took a used FW and converted it to 5s specification (with a LH pushrod, not operated by a bellcrank) and I used it for about 80000 miles before the (even older FG specification) axle finally broke. So they can be quite reliable. However I was then caught out by the 'cream cheese pawl pins' of a later (basically similar) SA5 internal, which broke after just a few thousand miles. In the meantime I used a ball locking sprinter and a (W) hub on city/utility bikes. I quite liked the ball locking sprinter and I (more or less) worked out how to live with the (W) hub too. Amongst the local cycling fraternity I am suspected of having a strong latent masochistic streak....
More in part two.
Last edited by Brucey on 18 Feb 2020, 9:29pm, edited 3 times in total.
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
part two;
Hub specifications, manual and parts list are to be found here
http://www.sturmey-archer.com/en/products/detail/rx-rd5
a couple of photos which show the problem with the hub in question
If you are used to older SA 5s hubs, it is difficult to get your head round one of these; nearly all the parts in the internal are about twice the size of older ones. RX-RD5 weighs about 800g more than a (W) model which was in turn slightly heavier than the previous 5s model to that. The flanges are drilled for spokes on a 95.5mm PCD and the screw thread that secures the internal is not that much smaller in diameter. The 'tiny' drive sprocket is 20T and would obscure the flanges on most older SA hubs. Practically the only thing which isn't oversized is the low gear dog ring; this is exactly the same size as that used on other, smaller SA hubs, despite the fact that these pawls see the highest torque loadings of any in the hub.
One change in this hub is that the ball ring appears to screw into the hubshell on a single-start thread; it was really quite difficult to unscrew it and release the internal. The NIG function is enabled via an external drag spring which is pinned to the ring gear and sits inside the ball ring. This disables the ring gear pawls if the bike is wheeled backwards in high gears but there is a penalty; the drag spring lives up to its name when pedalling in gears 1 and 2, and also when freewheeling in high gears.
The rotary shift actuation is operated via a RH cone with slots in it; the slots accommodate two steel pins which transfer the motion into the shift actuator parts inside the hub. A driver with two pawls engages with the ring gear in gears 1, 2 and 3 and the ring gear pawls are inhibited in gears 1 and 2 by the sliding clutch. Drive is taken from the ring gear to the hubshell in gear 3, and from the planet cage to the hubshell in gears 1 and 2. This much is normal, even if the parts are writ oversize.
One of the novel features in this hub is that there are four pawls inside the sun pinions, so that the suns can be selectively locked in either direction as the need arises. The suns see a forwards torque in the high gears and a backwards torque in the low gears. It is possible to test the sun locking function for gross errors without dismantling the hub completely, but this doesn't assure that the sun locking pawls are in perfect condition.
In gears 4 and 5 the sliding clutch is moved fully leftwards and drives the planet cage. The dogs on the sliding clutch are about three times the size of similar dogs in a (W) hub and they are set on a larger diameter too. The high gear drive ought to handle at least four or five times the torque of the earlier hubs.
However this hub has failed because the sliding clutch has been slipping in the high gears, and this has damaged the planet cage, turning what should be square-edged dogs into ramps. It seems that the planet cage is made from an incredibly soft steel of some kind; the driver dogs are much harder and are unmarked despite having removed about 1 cm^3 of steel from the planet cage, and there are shards of steel strewn throughout that part of the hub.
I'd assume that the slippage started when the clutch wasn't fully engaged with the planet cage; this could have happened when the hub was downshifted from 5 to 4 if the shifter was sticky/backlashy and stuck halfway between gear 4 and gear 3, or the adjustment was bad. Or just a clumsy shift perhaps, under load. The sliding clutch has large dogs on it, but they are not very deep, and (being made via powder met presumably) are also made square rather than undercut. The result is that just one or two slippage events at this interface might be enough to wear the planet cage part of the interface into a 'rejection ramp' of some kind, doomed to slip thereafter, under load. Under the highest loads or if the axle is slightly deformed into a curve when it is installed, the sliding clutch might 'walk out of engagement' with the planet cage even if the whole thing is in good order.
However where to pin the blame exactly for this hub failure is a tough question; there are just too many suspects. The cable was bad, the shifter was bad (backlashy and almost seized solid), and the gear adjustment was probably bad too. It is difficult to say for sure because the shifter was so bad, and in addition the gear setting marks are not super-clear on the hub anyway; there are meant to be coloured marks to line up in gear 2, but you are supposed to use different marks depending on type of dropout in use, and the marks are the first things to be obscured by road dirt. That is assuming that they are not obscured by a chaincase anyway. [it could be possible to make machined alignment marks between the cable pulley and the RH cone; these would stay the same regardless of the dropout type, and could still be visible even when dirty.]
Because of the way the thumbshifter is mounted, it sticks out forwards from the handlebar. If you park the bike and lean it against a wall, there's a pretty fair chance that the shifter will be taking some of the load; this shifter is quite badly scuffed as a result of this kind of thing. In addition the shifter top appears to work a bit like a funnel for rainwater; the shifter internals were oil-free and going rusty from rainwater penetration.
You may be thinking "well it lasted three years, how bad could it be?". Worse than you might think; this is apparently internal number 3 for this bike and I wouldn't be at all surprised if the others went the same way.
I suspect that someone with more mechanical sympathy might have stopped using the hub when it started slipping and investigated before there was about 1cm^3 of swarf floating round inside the hub. This hub needs at least a new planet cage assembly (HSA907) before it has any chance of working again, but I can't find that part for sale, and if it is priced like other similar parts in other hubs, it won't be cheap. [You can buy a complete internal and it retails over £100. ] It seems a bit crazy to me to make the softer, wearing part of a clutch the one that is expensive to replace; it would have made more sense to have made it so that the sliding clutch would wear and not the planet cage.
So overall, did this hub 'die of natural causes' or was it 'murdered'? Despite my misgivings about the design, I'd say more the latter than the former.
cheers
Hub specifications, manual and parts list are to be found here
http://www.sturmey-archer.com/en/products/detail/rx-rd5
a couple of photos which show the problem with the hub in question
If you are used to older SA 5s hubs, it is difficult to get your head round one of these; nearly all the parts in the internal are about twice the size of older ones. RX-RD5 weighs about 800g more than a (W) model which was in turn slightly heavier than the previous 5s model to that. The flanges are drilled for spokes on a 95.5mm PCD and the screw thread that secures the internal is not that much smaller in diameter. The 'tiny' drive sprocket is 20T and would obscure the flanges on most older SA hubs. Practically the only thing which isn't oversized is the low gear dog ring; this is exactly the same size as that used on other, smaller SA hubs, despite the fact that these pawls see the highest torque loadings of any in the hub.
One change in this hub is that the ball ring appears to screw into the hubshell on a single-start thread; it was really quite difficult to unscrew it and release the internal. The NIG function is enabled via an external drag spring which is pinned to the ring gear and sits inside the ball ring. This disables the ring gear pawls if the bike is wheeled backwards in high gears but there is a penalty; the drag spring lives up to its name when pedalling in gears 1 and 2, and also when freewheeling in high gears.
The rotary shift actuation is operated via a RH cone with slots in it; the slots accommodate two steel pins which transfer the motion into the shift actuator parts inside the hub. A driver with two pawls engages with the ring gear in gears 1, 2 and 3 and the ring gear pawls are inhibited in gears 1 and 2 by the sliding clutch. Drive is taken from the ring gear to the hubshell in gear 3, and from the planet cage to the hubshell in gears 1 and 2. This much is normal, even if the parts are writ oversize.
One of the novel features in this hub is that there are four pawls inside the sun pinions, so that the suns can be selectively locked in either direction as the need arises. The suns see a forwards torque in the high gears and a backwards torque in the low gears. It is possible to test the sun locking function for gross errors without dismantling the hub completely, but this doesn't assure that the sun locking pawls are in perfect condition.
In gears 4 and 5 the sliding clutch is moved fully leftwards and drives the planet cage. The dogs on the sliding clutch are about three times the size of similar dogs in a (W) hub and they are set on a larger diameter too. The high gear drive ought to handle at least four or five times the torque of the earlier hubs.
However this hub has failed because the sliding clutch has been slipping in the high gears, and this has damaged the planet cage, turning what should be square-edged dogs into ramps. It seems that the planet cage is made from an incredibly soft steel of some kind; the driver dogs are much harder and are unmarked despite having removed about 1 cm^3 of steel from the planet cage, and there are shards of steel strewn throughout that part of the hub.
I'd assume that the slippage started when the clutch wasn't fully engaged with the planet cage; this could have happened when the hub was downshifted from 5 to 4 if the shifter was sticky/backlashy and stuck halfway between gear 4 and gear 3, or the adjustment was bad. Or just a clumsy shift perhaps, under load. The sliding clutch has large dogs on it, but they are not very deep, and (being made via powder met presumably) are also made square rather than undercut. The result is that just one or two slippage events at this interface might be enough to wear the planet cage part of the interface into a 'rejection ramp' of some kind, doomed to slip thereafter, under load. Under the highest loads or if the axle is slightly deformed into a curve when it is installed, the sliding clutch might 'walk out of engagement' with the planet cage even if the whole thing is in good order.
However where to pin the blame exactly for this hub failure is a tough question; there are just too many suspects. The cable was bad, the shifter was bad (backlashy and almost seized solid), and the gear adjustment was probably bad too. It is difficult to say for sure because the shifter was so bad, and in addition the gear setting marks are not super-clear on the hub anyway; there are meant to be coloured marks to line up in gear 2, but you are supposed to use different marks depending on type of dropout in use, and the marks are the first things to be obscured by road dirt. That is assuming that they are not obscured by a chaincase anyway. [it could be possible to make machined alignment marks between the cable pulley and the RH cone; these would stay the same regardless of the dropout type, and could still be visible even when dirty.]
Because of the way the thumbshifter is mounted, it sticks out forwards from the handlebar. If you park the bike and lean it against a wall, there's a pretty fair chance that the shifter will be taking some of the load; this shifter is quite badly scuffed as a result of this kind of thing. In addition the shifter top appears to work a bit like a funnel for rainwater; the shifter internals were oil-free and going rusty from rainwater penetration.
You may be thinking "well it lasted three years, how bad could it be?". Worse than you might think; this is apparently internal number 3 for this bike and I wouldn't be at all surprised if the others went the same way.
I suspect that someone with more mechanical sympathy might have stopped using the hub when it started slipping and investigated before there was about 1cm^3 of swarf floating round inside the hub. This hub needs at least a new planet cage assembly (HSA907) before it has any chance of working again, but I can't find that part for sale, and if it is priced like other similar parts in other hubs, it won't be cheap. [You can buy a complete internal and it retails over £100. ] It seems a bit crazy to me to make the softer, wearing part of a clutch the one that is expensive to replace; it would have made more sense to have made it so that the sliding clutch would wear and not the planet cage.
So overall, did this hub 'die of natural causes' or was it 'murdered'? Despite my misgivings about the design, I'd say more the latter than the former.
cheers
Last edited by Brucey on 14 Mar 2020, 11:09pm, edited 5 times in total.
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
A fascinating piece of forensic pathology. Can't wait for Part II.
I should coco.
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
Very interesting.
Makes you wonder why they kept re-inventing something that originally worked well.
Makes you wonder why they kept re-inventing something that originally worked well.
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
Greystoke wrote:Very interesting.
Makes you wonder why they kept re-inventing something that originally worked well.
Makes me wonder why we can't buy TF or AM hubs, how many gears do you need
to run down to the pub ?
+++++++++++++++++++++++++
Deutsche Luftschiffahrts-AG
+++++++++++++++++++++++++
Deutsche Luftschiffahrts-AG
+++++++++++++++++++++++++
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- Posts: 26
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
I can't help but wonder if 'Brucey' isn't a committee or some sort of Artificial Intelligence...
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
Everything I read about hub gears on this forum puts me right off them.
Even worse that Sturmey managed to engineer a reliable 3-speed hub then totally dropped the ball with anything else, and repeated the same mistakes.
For the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
Even worse that Sturmey managed to engineer a reliable 3-speed hub then totally dropped the ball with anything else, and repeated the same mistakes.
For the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
bgnukem wrote:Everything I read about hub gears on this forum puts me right off them.
Even worse that Sturmey managed to engineer a reliable 3-speed hub then totally dropped the ball with anything else, and repeated the same mistakes.
For the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
I’d say the Shimano three, seven and eight speed hubs are all pretty good, with the caveat that they benefit greatly from a different (better) set-up and lubrication regime than the one proposed by Shimano. Basically, ensure the bearings are correctly adjusted, shove a load of semi-fluid grease that contains corrosion inhibitors in them and keep an eye on the cable condition and adjustment. That should keep them sweet. Obviously I mostly learnt this on this forum, from Brucey, but there are four IGH bikes in my household and I see many more at work, so I’m not without first hand experience.
Perhaps that’s a big caveat considering most users won’t do any of the above, but for at least the ITKs on this forum can get a reliable hub! And they are bloody great for utility bike use, I regularly curse having to clean and maintain my partner’s 3x9 speed fast commuter...
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
It is incredible to me how crap Sturmey Archer/Sunrace/Microshift gear levers are - even the solid looking aluminium bar ends are vastly inferior to Shimano. As Brucey mentioned they often end up mid-gear, an inconvenience for a derailleur but death for a hub...
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
bgnukem wrote:Everything I read about hub gears on this forum puts me right off them.
Even worse that Sturmey managed to engineer a reliable 3-speed hub then totally dropped the ball with anything else, and repeated the same mistakes.
For the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
funny that you should say that. exactly my thoughts too. hence my commuter bike remains fixed. the climb on my way home seems to lengthen year by year though.
good OP
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
bgnukem wrote:
For the UK climate a good reliable hub gear would be ideal on a utility or commuter bike but are ANY of them reliable apart from a 40 year old 3-speed???
a few are OK but they are the exception. In choosing between IGHs and derailleurs, it is arguably a question of choosing your preferred poison.
cheers
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Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
AndyA wrote:It is incredible to me how crap Sturmey Archer/Sunrace/Microshift gear levers are - even the solid looking aluminium bar ends are vastly inferior to Shimano. As Brucey mentioned they often end up mid-gear, an inconvenience for a derailleur but death for a hub...
yep. However if you want to sidestep most of these issues, the LH SunRace shifters (both bar ends and thumbshifters which share the same internals) have a 'powershift' style ratchet in them, and they seem to be reasonably reliable too. Two LH bar end shifters is a good option, I reckon.
Little known facts about these shifters are
a) that it is usually possible to rebuild a RH thumbshifter using LH internals, so creating a RH shifter that SunRace doesn't sell and
b) you can mount a LH thumbshifter under the RH bar and it will be (IMHO) as easy or easier to use than when over the bar and
c) that if you use a LH shifter with a Dynasys 10s RD /10s cassette, you get almost exactly one downshift per two clicks in the shifter, thus what you might call 'semi-indexed' downshifts when you need them. (Friction upshifting has always seemed a much easier thing to me.)
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
AndyA wrote:It is incredible to me how crap Sturmey Archer/Sunrace/Microshift gear levers are - even the solid looking aluminium bar ends are vastly inferior to Shimano. As Brucey mentioned they often end up mid-gear, an inconvenience for a derailleur but death for a hub...
I have a bike with an Alfine 8 speed on it. And those Microshift shifters for drop bars. I bought the bike second hand, but I don't think it had done much. I had to spend a while persuading it to work. Turned out it was the hex nut thing on the end of the cable was loose. But in the few days before I got to the bottom of it, I had quite a few grindy moments. This hub may well end up on a mini-tour in a place a long way from anything like a bike shop, so I wouldn't like it to fail. Questions:
1. Might it be damaged from a bit of grinding, between gears?
2. How could I tell, either by listening, or taking it apart?
3. If it's just a bit sorta damaged, could it still fail suddenly?
Thanks.
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
1. Yes
2. You can't be 100% sure without taking it to bits, inspecting it, reassembling it (if it looks OK) and then riding it.
3. Yes, possibly.
A good way of assessing whether there is ongoing wear/damage in an IGH is to run it in oil for a while and then assess the oil, e.g. visually and/or using a magnet. If the magnet comes out of the oil covered in swarf or rust, you can be pretty certain that something evil is occurring within the hub.
cheers
2. You can't be 100% sure without taking it to bits, inspecting it, reassembling it (if it looks OK) and then riding it.
3. Yes, possibly.
A good way of assessing whether there is ongoing wear/damage in an IGH is to run it in oil for a while and then assess the oil, e.g. visually and/or using a magnet. If the magnet comes out of the oil covered in swarf or rust, you can be pretty certain that something evil is occurring within the hub.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: RX-RD5; another flawed Sturmey Archer 5s hub? -surely not....
Brucey wrote:1. Yes
2. You can't be 100% sure without taking it to bits, inspecting it, reassembling it (if it looks OK) and then riding it.
3. Yes, possibly.
A good way of assessing whether there is ongoing wear/damage in an IGH is to run it in oil for a while and then assess the oil, e.g. visually and/or using a magnet. If the magnet comes out of the oil covered in swarf or rust, you can be pretty certain that something evil is occurring within the hub.
cheers
thanks again.
This is an SG-501. Is it possible just to take out the internals and replace them as one unit? To save the cost of rebuilding the wheel round a new hub.