bettybl

What is SRAM 3.0 used for? And how is it used? I realized that a 24 speed bike has 3 numbers on left, and then 8 numbers on right.

Does that mean SRAM on 2 and Right number on 8 mean the 16th speed? I have tried a bike like this and found that this "16th speed" is actually much easier to pedal than on another bike at regular 6th speed. I'm not really understanding what SRAM is. Does it make the bike much heavier?

badmother

not sure, but I think this is the hub I asked about appro one week ago. If I am right this is a rear hub with 2 or three internal gears plus also a casette for a normal der setup.

This system is good if you want more gears but want to avoid the front chainrings. On a folder more than one front chainring can be a challenge both becouse of chainline and fold. Also it looks like the peopel who try a 9speed casette with only one front chainring is struggeling with chaindrop.

I would guess a bike with this type gearing is a bit heavyer than a bike with a similar der geared bike. It is the same old story: do you want small fold, light bike or plenty gears? Can not have it all.

I am not sure if this type of gearing is easyer to pedal than other folders, but it could be that this bike had the gears you needed. With a lot of gears it is easyer to find the ones you want. On a bike with few (or only one gear) it is important the gears are the right ones for you.

If you`ve got 21 pairs of shoes but only one or two fit your size you are not really happy. If all 21 pairs are jogging shoes you are still not able to dress up for a party.

I am seriousely interested in this setup for two of my "BMX folders" that i think is going to do more and more of the "beater bike"and "utilitybike" jobs around here. So far I am happy with my Nexus 7 hub gears, but if I am going to get rid of my MTB`s and hybrds as planned I want this gearing.

badmother

folder.fanatic posted this in the Tikit vs Brompton thread. It is from the BF site and is a wery good description of the system.

SRAM Dual Drive 3 speed INTERNAL HUB: This is an innovation that works particularly well with the Bike Friday's 20" wheel diameter. The system looks like this: single front chainring (no front derailleur), and in the rear wheel, an enclosed, planetary gear system that performs the same function as the front chainrings, in combination with a standard 7,8, or 9 cog cassette to give a total of 21-27 gears.

The advantages: Wider gear range than a triple chainring, robust, bullet proof casing which makes it great for touring. If you climb really steep hills or like really low gears, this is it! Unlike earlier editions of this hub, you can shift it while pedaling.

The disadvantages: generally a pound heavier than a typical chainring setup, and though it is a reliable component, it is not as easy to repair on the road in the unlikely even that it fails. However, it is designed to be a fully enclosed, relatively maintenance-free system.

rbrian

SRAM 3.0 doesn't refer to the number of gears, but the quality of the groupset, the higher the number the better.