While this topic category has me confused as to whether it is for IGH's or Motorized Hubs with gearing, I will post here anyway.
I currently have a Sturmey Archer XL-RD3 IGH on the rear. It has a 90mm drum brake and 133% gear range, 3 speed Internally Geared Hub. 2nd gear is straight through 1:1 or 100%. Gear 1 and 3 are +/- 33% respectively. I have a 13 tooth cog on it driven by a 48 tooth Chainring up front. It decided to have issues and needs to be rebuilt or replaced. The damage is due to the way S/A designed the gear shift mechanism. The little chain indicator part snapped off inside the hub right at the thread line. After researching online, it seems this is a common failure, even when installed correctly(the 1/2 turn back off from fully tightened). It obviously has been such an issue that Sturmey re-engineered that part of their hub lines to a newer "rotor" style adjustment of gears. The newer design makes adjustments much easier and simpler, and no longer has any parts that protrude from the bike past the frame(other than the bolts on each side). On top of those 2 improvements, the "rotor" style is supposedly more robust and less prone to breakage. So, I have decided it is a better use of my money to go ahead and replace the hub instead of just rebuilding it. I could rebuild my current one for around $55. That is around half the cost of the hub itself. The hub I am looking at replacing my XL-RD3 with is the X-RD8. Yes, it is only a 70mm brake on that unit, but its a rear wheel, the front will keep its 90mm drum hub. The idea is due to the X-RD8 1st gear is the 100% or 1:1 straight thru gear, with the following gears at +30%,+14%,+14%,+14%,+14%,+14%,+30%. For a gear range of 325% vs 133% for the 3 speed. That is a HUGE difference, and the "start" gear(1) is still a straight thru pass to maintain strength in the gear the highest torque would be applied during take offs or hills. So instead of starting in 2nd like now, I would be starting in 1st. Granted I will no longer have a "granny" gear for hills, but 1) this is a road bike/ cruiser. Not offroading on it, and 2) I will be swapping the current 13T rear cog for a 23T or 24T which will give me a considerable amount more of torque for those occasional hills. I rarely ever used 1st on the current set up, as 2nd was fine for the hills near me. I think the extra torque from the cog swap should off set any issues on the low end, but with HUGE gains on the high end. So those of you more knowledgeable than I on these hubs, or those who wouldnt mind doing the math(feeling lazy, but may just have to do it to see) that can give me some good input as to how the 2 setups would compare/ differ for me. My only concern is the new hub(X-RD8) in 1st even with a 24T cog would not be able to climb a decent hill. Again, I am not talking about taking it on any trails. This bike ONLY knows the pavement and maybe some sand. I ride this 60-80% of the time to work and back. There are not many BIG hills here in town, but I am close to Skyline Drive, VA. So hills and mountains are nearby. I would just like a little re-assuring before ordering and swapping all these parts out. Not to mention re-lacing the wheel. I think that is all the technical info on the 2 setups I have to give. Oh, this is all on a cruiser(see avitar/pic or my build page) that weighs aprox 90lbs, has 26"x3" tires on 65mm rims, and powered with the BBSHD at 52v(dual 50amp capable 12.5ah packs in parallel). I am also about to finalize the decision between the Ludi or Phaserunner, so the BBSHD will have more torque(Ludi) and quite possible spin faster(phaserunner) soon. So the low gear may be moot at that point as it will be 2500-3k watts.
I currently have a Sturmey Archer XL-RD3 IGH on the rear. It has a 90mm drum brake and 133% gear range, 3 speed Internally Geared Hub. 2nd gear is straight through 1:1 or 100%. Gear 1 and 3 are +/- 33% respectively. I have a 13 tooth cog on it driven by a 48 tooth Chainring up front. It decided to have issues and needs to be rebuilt or replaced. The damage is due to the way S/A designed the gear shift mechanism. The little chain indicator part snapped off inside the hub right at the thread line. After researching online, it seems this is a common failure, even when installed correctly(the 1/2 turn back off from fully tightened). It obviously has been such an issue that Sturmey re-engineered that part of their hub lines to a newer "rotor" style adjustment of gears. The newer design makes adjustments much easier and simpler, and no longer has any parts that protrude from the bike past the frame(other than the bolts on each side). On top of those 2 improvements, the "rotor" style is supposedly more robust and less prone to breakage. So, I have decided it is a better use of my money to go ahead and replace the hub instead of just rebuilding it. I could rebuild my current one for around $55. That is around half the cost of the hub itself. The hub I am looking at replacing my XL-RD3 with is the X-RD8. Yes, it is only a 70mm brake on that unit, but its a rear wheel, the front will keep its 90mm drum hub. The idea is due to the X-RD8 1st gear is the 100% or 1:1 straight thru gear, with the following gears at +30%,+14%,+14%,+14%,+14%,+14%,+30%. For a gear range of 325% vs 133% for the 3 speed. That is a HUGE difference, and the "start" gear(1) is still a straight thru pass to maintain strength in the gear the highest torque would be applied during take offs or hills. So instead of starting in 2nd like now, I would be starting in 1st. Granted I will no longer have a "granny" gear for hills, but 1) this is a road bike/ cruiser. Not offroading on it, and 2) I will be swapping the current 13T rear cog for a 23T or 24T which will give me a considerable amount more of torque for those occasional hills. I rarely ever used 1st on the current set up, as 2nd was fine for the hills near me. I think the extra torque from the cog swap should off set any issues on the low end, but with HUGE gains on the high end. So those of you more knowledgeable than I on these hubs, or those who wouldnt mind doing the math(feeling lazy, but may just have to do it to see) that can give me some good input as to how the 2 setups would compare/ differ for me. My only concern is the new hub(X-RD8) in 1st even with a 24T cog would not be able to climb a decent hill. Again, I am not talking about taking it on any trails. This bike ONLY knows the pavement and maybe some sand. I ride this 60-80% of the time to work and back. There are not many BIG hills here in town, but I am close to Skyline Drive, VA. So hills and mountains are nearby. I would just like a little re-assuring before ordering and swapping all these parts out. Not to mention re-lacing the wheel. I think that is all the technical info on the 2 setups I have to give. Oh, this is all on a cruiser(see avitar/pic or my build page) that weighs aprox 90lbs, has 26"x3" tires on 65mm rims, and powered with the BBSHD at 52v(dual 50amp capable 12.5ah packs in parallel). I am also about to finalize the decision between the Ludi or Phaserunner, so the BBSHD will have more torque(Ludi) and quite possible spin faster(phaserunner) soon. So the low gear may be moot at that point as it will be 2500-3k watts.
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