September 3, 201411 yr I was with Shimano last week at Eurobike. I asked their tech Director what the maximum electronic power they would allow through ANY of their transmission systems, as we can turn the new Kombi centre motor up to well beyond 100Nm. His reply was 30Nm from standstill building up to 50Nm when the bike was moving otherwise the Shimano components will not be within warranty. Worth remembering when purchasing a mid motor bike. The best set up is a Nuvinci 360 through a Gates or Continental carbon belt, but that is expensive. Hub motors of course don't have to go through the bike's transmission. All the best David yes, I used to have a giant lafree/twist that aye hub gears (went through three in as many years). incongruously though my OH's klakhof tasman remains fine despite her (and me) putting much more than the maximum 70nM through its shimano 8 speed hub. I frankly don't understand it (I assume its the pause thingy between gears that make the teeth mesh much more completely)..
September 3, 201411 yr ... incongruously though my OH's klakhof tasman remains fine despite her (and me) putting much more than the maximum 70nM through its shimano 8 speed hub. I frankly don't understand it (I assume its the pause thingy between gears that make the teeth mesh much more completely).. the Bosch Classic motor in the Tasman has 44T on the front cog, 20T on the Alfine-8 on the rear cog, the maximum torque transmitted to the rear cog is 50NM * 20/44 = 22.7NM, within the recommendations.
September 3, 201411 yr yes, I used to have a giant lafree/twist that aye hub gears (went through three in as many years). incongruously though my OH's klakhof tasman remains fine despite her (and me) putting much more than the maximum 70nM through its shimano 8 speed hub. I frankly don't understand it (I assume its the pause thingy between gears that make the teeth mesh much more completely).. The four speed Shimano hub gear that was on one of the Lafree range for a while suffered numerous failures and as a result, Shimano discontinued it. That was replaced by the SRAM 5 speed and later the SRAM 7 speed hub gear, but they suffered a very slow downward gear change. Trying to rush those usually lead to eventual trouble due to chips of metal being broken away and either breaking up the rest or jamming the gear stationary. The much larger diameter Shimano 8 speed hubs have more robust components, probably contributing to the better reliability. . Edited September 3, 201411 yr by flecc
September 3, 201411 yr the Bosch Classic motor in the Tasman has 44T on the front cog, 20T on the Alfine-8 on the rear cog, the maximum torque transmitted to the rear cog is 50NM * 20/44 = 22.7NM, within the recommendations. I'm afraid youre wrong - teh tasman with impulse 2 (that's all tasmans that are less than a year old) have an impulse 2 motor with 70 nM.
September 3, 201411 yr The four speed Shimano hub gear that was on one of the Lafree range for a while suffered numerous failures and as a result, Shimano discontinued it. That was replaced by the SRAM 5 speed and later the SRAM 7 speed hub gear, but they suffereed a very slow downward gear change. Trying to rush those usually lead to eventual trouble due to chips of metal being broken away and either breaking up the rest or jamming the gear stationary. The much larger diameter Shimano 8 speed hubs have more robust components, probably contributing to the better reliability. . one other thing that makes shimano 8 speeds attractive are that their very cheap..
September 3, 201411 yr the Bosch Classic motor in the Tasman has 44T on the front cog, 20T on the Alfine-8 on the rear cog, the maximum torque transmitted to the rear cog is 50NM * 20/44 = 22.7NM, within the recommendations. but you are right to bring in the way gears (naturally) affect torque on a hub, it's easilly overlooked (though my lafree with all of its 24 V nonetheles ate all hubs - sram included - until i put in a rohloff )
September 3, 201411 yr I was with Shimano last week at Eurobike. I asked their tech Director what the maximum electronic power they would allow through ANY of their transmission systems, as we can turn the new Kombi centre motor up to well beyond 100Nm. His reply was 30Nm from standstill building up to 50Nm when the bike was moving otherwise the Shimano components will not be within warranty. Worth remembering when purchasing a mid motor bike. The best set up is a Nuvinci 360 through a Gates or Continental carbon belt, but that is expensive. Hub motors of course don't have to go through the bike's transmission. All the best David I was with Shimano last week at Eurobike. I asked their tech Director what the maximum electronic power they would allow through ANY of their transmission systems, as we can turn the new Kombi centre motor up to well beyond 100Nm. His reply was 30Nm from standstill building up to 50Nm when the bike was moving otherwise the Shimano components will not be within warranty. Worth remembering when purchasing a mid motor bike. The best set up is a Nuvinci 360 through a Gates or Continental carbon belt, but that is expensive. Hub motors of course don't have to go through the bike's transmission. All the best David 30Nm from rest is remarkably low when a 15 stone rider standing on the pedals exerts a torque of over 140Nm.
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