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#1
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Are two bicycles necessary?
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#2
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Are two bicycles necessary?
Johnny Sunset aka Tom Sherman wrote:
....This is the recumbent bike I would choose for touring: -RANS Rocket- (and not just because I already own one). Certainly people do tour on the Rocket, but the weird back wheel scares me. If the Sachs hub goes out on tour, how easy would it be to find another replacement? Is the "typical" bike shop going to have one on hand in that size? Probably not. ....This is my justification for suggesting a 26/26 LWB bike that uses regular derailleurs. The more common parts the recumbent has, the better. (the Cycle Genius I suggested does use disk brakes, but those are pretty common now on bike-store MTB's, which also use 26" wheels--and if a rim goes out of true, you're more likely to be able to keep riding on it it if you have disk brakes than calipers) The RANS Rocket is also a very fun bike to ride, once the rider adapts to the light control forces required. I had a short wheelbase at first and didn't like it, mainly for one reason--that it was fine on smooth clean pavement, but it did not handle well in gravel and broken pavement at all. Normally you would not choose to ride on gravelly or broken pavement of course, but during emergency evasive maneuvers sometimes you end up taking a path that you wouldn't choose otherwise. And it was at these exact moments that the SWB felt its worst, as if it was going to slide sideways out from under me. The LWB has this problem but it's much less severe. ~ |
#3
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Are two bicycles necessary?
DougC wrote:
Certainly people do tour on the Rocket, but the weird back wheel scares me. If the Sachs hub goes out on tour, how easy would it be to find another replacement? It's a two edged sword: hub gears are intrinsically more reliable than derailleurs so it's far less likely to go out in the first place. If you're on tour and 20 miles from anywhere, how easy will it be to get hold of a new derailleur? I think that's a lot more likely to happen than a dead hub. I had a short wheelbase at first and didn't like it, mainly for one reason--that it was fine on smooth clean pavement, but it did not handle well in gravel and broken pavement at all. Normally you would not choose to ride on gravelly or broken pavement of course, but during emergency evasive maneuvers sometimes you end up taking a path that you wouldn't choose otherwise. And it was at these exact moments that the SWB felt its worst, as if it was going to slide sideways out from under me. The LWB has this problem but it's much less severe. "SWB" and "LWB" don't tell you much on their own. You can have implementations of either that will suck or blow on different terrains. My SWB (HPVel Streetmachine GT) tourer is pretty much fine off the pavement (it's done a few miles in its time fully loaded for touring on unmade tracks), but I'd not be at all surprised to find SWBs that didn't do so well. 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/ |
#4
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Are two bicycles necessary?
DougC wrote: Johnny Sunset aka Tom Sherman wrote: ....This is the recumbent bike I would choose for touring: -RANS Rocket- (and not just because I already own one). Certainly people do tour on the Rocket, but the weird back wheel scares me. If the Sachs hub goes out on tour, how easy would it be to find another replacement? Is the "typical" bike shop going to have one on hand in that size? Probably not. ....This is my justification for suggesting a 26/26 LWB bike that uses regular derailleurs. The more common parts the recumbent has, the better. The Rocket comes standard with a regular cassette hub - those with Sachs 3x7 hubs or SRAM DualDrive were modified by a dealer or owner. A RANS Rocket with a 47-406 rear tire, an 11-34 Shimano Megarange cassette, and standard 52/42/30 "road" triple will have a gear range of about 1.4 to 7.4 meters development (17 to 92 gear inches). This will produce speeds from about 7½ to 40 kph (4½ to 25 mph) at a cadence of 90 rpm, which should be adequate for most touring use. The ISO 406-mm rear wheel of the Rocket will be significantly stronger than a larger wheel with the same number of spokes, which is also an advantage in touring. (the Cycle Genius I suggested does use disk brakes, but those are pretty common now on bike-store MTB's, which also use 26" wheels--and if a rim goes out of true, you're more likely to be able to keep riding on it it if you have disk brakes than calipers) The RANS Rocket is also a very fun bike to ride, once the rider adapts to the light control forces required. I had a short wheelbase at first and didn't like it, mainly for one reason--that it was fine on smooth clean pavement, but it did not handle well in gravel and broken pavement at all. Normally you would not choose to ride on gravelly or broken pavement of course, but during emergency evasive maneuvers sometimes you end up taking a path that you wouldn't choose otherwise. And it was at these exact moments that the SWB felt its worst, as if it was going to slide sideways out from under me. The LWB has this problem but it's much less severe. I would much rather ride a SWB on loose surfaces than a LWB. With an approximate 40%/60% front/rear weight distribution, the Rocket's front wheel is less likely to skid on loose surfaces, while still having an effective rear brake. The inherent SWB advantage in low speed handling can also be helpful on unimproved surfaces. The LWB will typically ride better (especially a bike with some vertical compliance such as the RANS Stratus). -- Tom Sherman - Post Free or Die! |
#5
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Are two bicycles necessary?
"Johnny Sunset aka Tom Sherman" wrote in message ups.com... DougC wrote: Johnny Sunset aka Tom Sherman wrote: ....This is the recumbent bike I would choose for touring: -RANS Rocket- (and not just because I already own one). Ed Dolan wrote: In all my years of touring I have seen very few Rockets ever used for that purpose. 20 inch wheels are best suited for around town, not for the open road. Certainly people do tour on the Rocket, but the weird back wheel scares me. If the Sachs hub goes out on tour, how easy would it be to find another replacement? Is the "typical" bike shop going to have one on hand in that size? Probably not. ....This is my justification for suggesting a 26/26 LWB bike that uses regular derailleurs. The more common parts the recumbent has, the better. The Rocket comes standard with a regular cassette hub - those with Sachs 3x7 hubs or SRAM DualDrive were modified by a dealer or owner. A RANS Rocket with a 47-406 rear tire, an 11-34 Shimano Megarange cassette, and standard 52/42/30 "road" triple will have a gear range of about 1.4 to 7.4 meters development (17 to 92 gear inches). This will produce speeds from about 7½ to 40 kph (4½ to 25 mph) at a cadence of 90 rpm, which should be adequate for most touring use. The ISO 406-mm rear wheel of the Rocket will be significantly stronger than a larger wheel with the same number of spokes, which is also an advantage in touring. Ed Dolan wrote: Please take all those metric measurements and put them where the sun don't shine. Or better yet, get thee to France (your true home) where such nonsense is the norm. (the Cycle Genius I suggested does use disk brakes, but those are pretty common now on bike-store MTB's, which also use 26" wheels--and if a rim goes out of true, you're more likely to be able to keep riding on it it if you have disk brakes than calipers) The RANS Rocket is also a very fun bike to ride, once the rider adapts to the light control forces required. I had a short wheelbase at first and didn't like it, mainly for one reason--that it was fine on smooth clean pavement, but it did not handle well in gravel and broken pavement at all. Normally you would not choose to ride on gravelly or broken pavement of course, but during emergency evasive maneuvers sometimes you end up taking a path that you wouldn't choose otherwise. And it was at these exact moments that the SWB felt its worst, as if it was going to slide sideways out from under me. The LWB has this problem but it's much less severe. I would much rather ride a SWB on loose surfaces than a LWB. With an approximate 40%/60% front/rear weight distribution, the Rocket's front wheel is less likely to skid on loose surfaces, while still having an effective rear brake. The inherent SWB advantage in low speed handling can also be helpful on unimproved surfaces. The LWB will typically ride better (especially a bike with some vertical compliance such as the RANS Stratus). Ed Dolan wrote: I think most of us would rather take a fall from a LWB than a SWB. The fact is that no recumbent rides at all well on rough surfaces unless it has been modified for such use, the principal modification being fat knobby tires. Regards, Ed Dolan the Great - Minnesota aka Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota |
#6
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Are two bicycles necessary?
Johnny Sunset aka Tom Sherman wrote:
.... The Rocket comes standard with a regular cassette hub - those with Sachs 3x7 hubs or SRAM DualDrive were modified by a dealer or owner. .... Well nuts. Both the Rockets I have seen (on opposite ends of the USA no less) had geared hubs. -?- I assumed they came that way. Both people /were/ touring on them. I would much rather ride a SWB on loose surfaces than a LWB. With an approximate 40%/60% front/rear weight distribution, the Rocket's front wheel is less likely to skid on loose surfaces, while still having an effective rear brake. The inherent SWB advantage in low speed handling can also be helpful on unimproved surfaces. The LWB will typically ride better (especially a bike with some vertical compliance such as the RANS Stratus). On the LWB I have, the seat is adjusted almost all the way back and I weigh 275 lbs, and the weight distribution on the rear is still only about 66%. I calculated that (on this bike) to push the weight distribution to 80% rear at my height (6'2") I would need to weigh ~450 lbs. As far as riding in gravel, I just advise people try it and see. A LWB is more stable than a SWB for the same reason that drag racers and sand rails are built long--simply the longer wheelbase. The reason that front tires on bents slide is simple: in a misguided effort to achieve minimal rolling resistance, people run tires too narrow and inflated to a pressure that is too high. The front tire should be inflated to a pressure (with respect to the rear tire) that is no greater than the proportion of weight that it is carrying. On the LWB above for instance--the rear tire is 100 PSI, the front tire is 45 PSI. If there is a risk of damage from inflating a narrow front tire to a lower pressure--then you simply need a wider tire in front. ~ |
#7
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Are two bicycles necessary?
DougC wrote:
As far as riding in gravel, I just advise people try it and see. A LWB is more stable than a SWB for the same reason that drag racers and sand rails are built long--simply the longer wheelbase. One person's "more stable" is another's "less responsive". If I'm in gravel and thing start to slide I think I'd sooner be on "more responsive" but of course mileage varies. The reason that front tires on bents slide is simple: in a misguided effort to achieve minimal rolling resistance, people run tires too narrow and inflated to a pressure that is too high. The front tire should be inflated to a pressure (with respect to the rear tire) that is no greater than the proportion of weight that it is carrying. I'd have thought that the weight distribution will change dramatically under heavy braking, which is one of the occasions you're likely to be sliding the front wheel... It will also change when you're going up a steep hill. Personally, ICBA to reinflate my tyres to different pressures according to the slope I'm on or the braking effect! 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/ |
#8
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Are two bicycles necessary?
DougC wrote:
:: The reason that front tires on bents slide is simple: in a misguided :: effort to achieve minimal rolling resistance, people run tires too :: narrow and inflated to a pressure that is too high. The front tire :: should be inflated to a pressure (with respect to the rear tire) :: that is no greater than the proportion of weight that it is :: carrying. On the LWB above for instance--the rear tire is 100 PSI, :: the front tire is 45 PSI. If there is a risk of damage from :: inflating a narrow front tire to a lower pressure--then you simply :: need a wider tire in front. ~ Really? You're saying that if I'm riding a 26/26 (SXP) with 100 PSI (max) tires and I max the rear I should make the front at 45 PSI? What about pinch flats and stuff? Would those mainly be limited to the rear tire? |
#9
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Are two bicycles necessary?
Roger Zoul wrote:
Really? You're saying that if I'm riding a 26/26 (SXP) with 100 PSI (max) tires and I max the rear I should make the front at 45 PSI? What about pinch flats and stuff? Would those mainly be limited to the rear tire? It depends on what the weight distribution of the particular bike/rider combination is. Put the front tire on a bathroom scale, and sit on the bike with your feet resting on the pedals and hold yourself up with a hand against a wall. Then with the rider and bike total weights you can figure it out. The front tire should have /at/ /least/ the same contact patch are as the rear, /if/ /not/ /more/. So for a bike that carries two-thirds of its weight on the rear tire, then the front should be inflated to no more than about one-half the pressure of the rear. If the weight distribution was 40/60 F/R, then the front tire should be inflated to no more than 2/3 the pressure of the rear. For a 45/55 F/R bike, the front should be no more than about 80% of the rear pressure. There will be no greater danger of a pinch flat in the lower-inflated front tire because while the pressure is lower, the load on the tire is lower as well. You are not "increasing" the risk of pinch flats as much as you are equalizing it; if both were inflated to the same pressure but the rear was carrying more weight, then the rear would be more at risk for pinching. You are not saving much of anything by over-inflating the front tire; the decrease in rolling resistance is minuscule. All it really gets you is much worse steering response. ......If the thought of a front pinch flat concerns you and you decide to run a wider front tire, then it should be at a pressure that is even lower than the weight proportion. The front needs to be re-figured based on the proportions of the wider front tire to the narrower rear. [-I should probably put up a web page explaining all this-] --------------- The problem I think is that people are used to upright bikes, that all tend to hold very-close-to 50/50 weight distribution, so people inflate both [recumbent] tires to the same PSI and forget about it. On a bike with significantly-different front/rear weight distribution, inflating both tires to the same pressure is simply not correct. ~ |
#10
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Are two bicycles necessary?
"DougC" wrote in message ... Roger Zoul wrote: Really? You're saying that if I'm riding a 26/26 (SXP) with 100 PSI (max) tires and I max the rear I should make the front at 45 PSI? What about pinch flats and stuff? Would those mainly be limited to the rear tire? It depends on what the weight distribution of the particular bike/rider combination is. Put the front tire on a bathroom scale, and sit on the bike with your feet resting on the pedals and hold yourself up with a hand against a wall. Then with the rider and bike total weights you can figure it out. The front tire should have /at/ /least/ the same contact patch are as the rear, /if/ /not/ /more/. So for a bike that carries two-thirds of its weight on the rear tire, then the front should be inflated to no more than about one-half the pressure of the rear. If the weight distribution was 40/60 F/R, then the front tire should be inflated to no more than 2/3 the pressure of the rear. For a 45/55 F/R bike, the front should be no more than about 80% of the rear pressure. There will be no greater danger of a pinch flat in the lower-inflated front tire because while the pressure is lower, the load on the tire is lower as well. You are not "increasing" the risk of pinch flats as much as you are equalizing it; if both were inflated to the same pressure but the rear was carrying more weight, then the rear would be more at risk for pinching. You are not saving much of anything by over-inflating the front tire; the decrease in rolling resistance is minuscule. All it really gets you is much worse steering response. .....If the thought of a front pinch flat concerns you and you decide to run a wider front tire, then it should be at a pressure that is even lower than the weight proportion. The front needs to be re-figured based on the proportions of the wider front tire to the narrower rear. [-I should probably put up a web page explaining all this-] --------------- The problem I think is that people are used to upright bikes, that all tend to hold very-close-to 50/50 weight distribution, so people inflate both [recumbent] tires to the same PSI and forget about it. On a bike with significantly-different front/rear weight distribution, inflating both tires to the same pressure is simply not correct. Doug is quite correct about all of this, but the reason so many think otherwise is that they want to be as fast as possible no matter the road surface. And so they go for maximum pressure tires front and rear, never dreaming that comfort and security are far more important than mere speed. Normally, you never go very fast on rough or gravel roads anyway, but the main thing is that you do not want to be falling. Fat low pressure tires simply work better on gravel. Regards, Ed Dolan the Great - Minnesota aka Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota |
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