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#11
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Can Too High Gears be Lowered on SRAM Dualdrive?
In ,
Peter Clinch tweaked the Babbage-Engine to tell us: Changing from the 52 to the 42 gives a ~20% reduction to each of the gears. There's no reason not to go /very/ low on a trike, as you're not going to have balance issues at low speed. Though you /may/ run out of traction, as I discovered to my cost 2/3 of the way up the Koppenberg a few years ago :-( -- Dave Larrington http://www.legslarry.beerdrinkers.co.uk I have a shell collection, have you seen it? I keep it scattered on the world's beaches. |
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#12
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Can Too High Gears be Lowered on SRAM Dualdrive?
Peter Clinch wrote:
Roos' Dual-Drive equipped touring 'bent sports a 52 tooth front chainring if we're going to the NL, but a 42 tooth one at home where the hills are more freely available. That's interesting. Is it easy to swap around like that? I know Roos has the privilege of living with a seasoned bike expert, and perhaps is one herself, but in my case the Darth is quite a distance away. Does not the chain need shortening or lengthening when you change the spec on the chainring? EFR Ile de France |
#13
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Can Too High Gears be Lowered on SRAM Dualdrive?
Dave Larrington wrote:
Though you /may/ run out of traction, as I discovered to my cost 2/3 of the way up the Koppenberg a few years ago :-( How's that - wheels spinning around in place? Would this be because of slippery or muddy roads, or is it a mechanical problem? Could you regain traction by gearing up and then down again? Cheers, EFR Ile de France |
#14
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Can Too High Gears be Lowered on SRAM Dualdrive?
Artemisia wrote:
That's interesting. Is it easy to swap around like that? I know Roos has the privilege of living with a seasoned bike expert, and perhaps is one herself She's pretty much as competent as me, and while you may have me as a "seasoned bike expert" that doesn't make me a great mechanic by any stretch of the imagination! Nevertheless, it's pretty straightforward by our fairly, but not spectacularly, low standards. You unhook the chain from the chainwheel, undo the bolts holding the chainwheel onto the crank, remove it, put the new one in place and replace the bolts. If there's a chain protector disc you'll probably have to take that off and put it back on too, but again it's just a case of turning bolts. Does not the chain need shortening or lengthening when you change the spec on the chainring? Potentially: to some extent the chain tensioner at the back will take up the slack, but you may put it over its limits, depending on the size of the step. It's easy enough to find out empirically: if your gears start giving trouble, especially the higher ones, you'll probably need to shorten the chain a little. That's quite easy with a chain tool. If you get one, ask at the shop whether they have a spare bit of old chain to practise on. I use one of Park's "foolproof" ones, and I haven't managed to bugger it up yet, despite only using it once a blue moon. If it's a bit scary then /any/ bike shop should be able to do the job for you in minutes, if not seconds. Pete. -- Peter Clinch Medical Physics IT Officer Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net http://www.dundee.ac.uk/~pjclinch/ |
#15
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Can Too High Gears be Lowered on SRAM Dualdrive?
Artemisia wrote:
Dave Larrington wrote: Though you /may/ run out of traction, as I discovered to my cost 2/3 of the way up the Koppenberg a few years ago :-( How's that - wheels spinning around in place? Would this be because of slippery or muddy roads, or is it a mechanical problem? Could you regain traction by gearing up and then down again? While it's worse on muddy roads, make any road steep enough and the wheel will slip, simply a matter of not enough friction. You could change up, but then it might be simply too hard to move the pedals! It's worth noting that this is only a problem on /seriously/ steep hills (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks it's quite easy to run out of traction. At which point you get off and push... Pete. -- Peter Clinch Medical Physics IT Officer Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net http://www.dundee.ac.uk/~pjclinch/ |
#16
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Can Too High Gears be Lowered on SRAM Dualdrive?
Peter Clinch wrote:
Artemisia wrote: Dave Larrington wrote: Though you /may/ run out of traction, as I discovered to my cost 2/3 of the way up the Koppenberg a few years ago :-( How's that - wheels spinning around in place? Would this be because of slippery or muddy roads, or is it a mechanical problem? Could you regain traction by gearing up and then down again? While it's worse on muddy roads, make any road steep enough and the wheel will slip, simply a matter of not enough friction. You could change up, but then it might be simply too hard to move the pedals! the lane nr my folks house as it gets steeper gets worse, more holes and during winter/spring covered with shale,and well what ever washes off the hills. so bit of balancing act getting enought traction and so one can still turn the cranks, still it's not a hill one uses to get from A to B more for the i'll beat it. heh some of the folk in the village woun't drive their cars up it. it averages 20% with peaks well into the 30% mark along with nice slippy bits, its great fun attually in a hot sweaty, why am i doing this? kind of way It's worth noting that this is only a problem on /seriously/ steep hills (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks it's quite easy to run out of traction. At which point you get off and push... looks fun in a jiggly sort of way. Pete. roger -- www.rogermerriman.com |
#17
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Can Too High Gears be Lowered on SRAM Dualdrive?
Peter Clinch wrote:
It's worth noting that this is only a problem on /seriously/ steep hills (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks it's quite easy to run out of traction. At which point you get off and push... My hill is seriously steep. And it's not practical to get out and pull because on that kind of incline the SPD shoes just slip and slip, and the bike is so heavy that it pulls me over. I have had the trike lose traction on the dirt path that immediately follows or precedes the killer hill. But here it was just a case of too deep muddy goo. EFR Ile de France |
#18
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Can Too High Gears be Lowered on SRAM Dualdrive?
Artemisia wrote:
Peter Clinch wrote: It's worth noting that this is only a problem on /seriously/ steep hills (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks it's quite easy to run out of traction. At which point you get off and push... My hill is seriously steep. How seriously? Koppenberg is famously difficult for /professionals/. What's the actual gradient? There should be no trouble with traction on a typically surfaced 20% hill, and those are very unusual. And it's not practical to get out and pull because on that kind of incline the SPD shoes just slip and slip There shouldn't be any particular trouble walking up a 20% hill in a pair of recessed-cleat shoes as long as it isn't an expecially slippy road. the bike is so heavy that it pulls me over. It's a tricycle, it can't fall over, and if it can't fall over it'll have trouble pulling you with it! I have had the trike lose traction on the dirt path that immediately follows or precedes the killer hill. But here it was just a case of too deep muddy goo. Mud, ice, diesel, wet leaves, drain covers can have you lose traction on level ground. You're never going to resolve all traction problems, but that doesn't make bikes/trikes unusable. Pete. -- Peter Clinch Medical Physics IT Officer Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital Fax 44 1382 640177 Dundee DD1 9SY Scotland UK net http://www.dundee.ac.uk/~pjclinch/ |
#19
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Can Too High Gears be Lowered on SRAM Dualdrive?
In ,
Peter Clinch tweaked the Babbage-Engine to tell us: Artemisia wrote: Peter Clinch wrote: It's worth noting that this is only a problem on /seriously/ steep hills (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks it's quite easy to run out of traction. At which point you get off and push... My hill is seriously steep. How seriously? Koppenberg is famously difficult for /professionals/. What's the actual gradient? There should be no trouble with traction on a typically surfaced 20% hill, and those are very unusual. Koppenberg is about 20%; the problem is that there is sand between the cobblestones, so if the rear wheel gets into a longitudinal gap, you are stuffed. I've done 25% a few times, most notably Bushcombe Lane: http://preview.tinyurl.com/5mp5hu (redirects to streetmap.co.uk) at the start of the Cotswold Corker. I only had traction issues where it starts to level out, due to the mud, grit, water and skog(tm) which are frequently to be found strewn about the minor roads of the BRITONS' England in the month of February. On the steeper bits lower down I was OK, except for having to avoid those unable to remain upright and who were thus toppling gracelessly into the hedge, or the front gardens of householders unfortunate enough to live on the route. -- Dave Larrington http://www.legslarry.beerdrinkers.co.uk I am Wan, for I am pursued by the Army of Plums. |
#20
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Can Too High Gears be Lowered on SRAM Dualdrive?
Dave Larrington wrote:
In , Peter Clinch tweaked the Babbage-Engine to tell us: Artemisia wrote: Peter Clinch wrote: It's worth noting that this is only a problem on /seriously/ steep hills (see http://en.wikipedia.org/wiki/Koppenberg). But with muddy tracks it's quite easy to run out of traction. At which point you get off and push... My hill is seriously steep. How seriously? Koppenberg is famously difficult for /professionals/. What's the actual gradient? There should be no trouble with traction on a typically surfaced 20% hill, and those are very unusual. Koppenberg is about 20%; the problem is that there is sand between the cobblestones, so if the rear wheel gets into a longitudinal gap, you are stuffed. I've done 25% a few times, most notably Bushcombe Lane: Longstaff "double drive" sounds helpful here. BugBear |
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