SRAM Dual Drive vs. Sturmey Archer CSRF3

[floridabike]

I recently install a SRAM Dual Dive internal hub on the Cruzbike to compare with Sturmey Archer CSRF3 that I had been using. Both are 3 speed internal hubs with freewheel cassettes. The SRAM comes with it's shifter that utilizes both the hub and cassette shifter on the right handle bar. I have tested both internal hubs with good results using a standard 3 speed shifter so it's not necessary to use the SRAM shifter. Both the 8 or 9 speed cassette shifters work with either the SRAM or sturmey Archer cassettes.

The SRAM shifts faster and better under load but tends to be a little noisier. Has what sounds like a small chain jingle while pedaling and the usual clicking while coasting. After coasting, the Sturmey Archer seems to require about a 1/2 turn of the crank before it engages, something that I didn't like but got used to. If there is a difference in efficiency, it's not apparent.

I prefer the shifting mechanism of the Sturmey Archer with the pull rod and chain vs. the fragileness of the Dual Drive 'Click Box'. The Sturmey Archer's pull rod and chain doesn't protrude far from the exterior of the hub and fairly well protected. where as the 'Click Box' is fragile and unprotected. I think some protection cover is sold separately.

The SRAM uses a 2.66 mm pull rod diameter necked down to 1.94 mm which makes it very fragile. The Sturmey Archer's uses a 4 mm pull rod and well protected. When I tried to purchase a spare pull rod for the SRAM, I found everybody out of stock or back ordered. Must be a big demand for the rods or they are not being produced any more.

The SRAM dual drive sells for about $400 and the Sturmey Archer CSRF3 can be purchased for $75, significantly less. If cost is no concern and if caution is used to protect the click box, the SRAM is probably the better hub but the Sturmey Archer is certainly acceptable and will do the job.

Phil

 

[Vargas]

It is a huge price

It is a huge price difference!

I might try a SA at my Sofrider too.

Excuse me for the dumb questions:
1 - Does the SA also shift while stopped as the SRAM does? This to me is the true advantage of these internal hubs.
2 - Will it work with a Shimano rapid fire shifter?
3 - I use a Shimano Alivio groupset with a triple 44-32-20 on the front. Originally the smaller one was a 22T but I replaced it for a 20T (besides being fun I climb walls with my SR now). Which one of the three chainrings would I use with the SA?
4 - My cassette is a 11-34 9 speeds. What I really want to know is the range I'll have with the SA. Now my lowest relation is 20-34 and the highest one 44-11; which would be the lowest and highest with the SA?

Please confirm if my understanding is right. The SA says the rate is 75%, 100% and 133%. In case I am at 100% and running the 32-16 combination, and shift to 75%, it will be equivalent to running 32-16*75% = 32-12, and if I shift to 133% it will be equivalent to running 32-16*133% = 32-21; is this correct?

Does the SRAM also have the same 75%, 100% and 133% relation?

Thanks,

Vargas

 

[billyk]

SRAM push rods available at Bike Friday

I agree about the fragility of the SRAM push rods.

After I bent mine, I found replacements at bikefriday.com (Eugene Oregon) for the trivial cost of $3.50(US) for 2. They use these hubs in their folding bikes and have a good stock of many such parts, including the click box covers and etc.

BK

 

[floridabike]

Just a couple of quick

Just a couple of quick answers.

Yes, the SA shifts while stopped.

Yes, I have used the Shimano trigger shifter and also twist shifters with no problems.

I disassembled the chainring and removed the small and large rings and now just have the center 28 tooth.

I have used 12 - 23 with 9 speed, 11-28 with 7 speed and now using 11 -32 with 8 speed. All of these combination were used with the 28 chainring. I am using 1.95, 26" tires for rail trail riding. The 28 chainring and 32 on the hub will get me up any hill and the 28 and 11 will get me a comfortable 20 mph pedal speed. If I'm going faster than that I just enjoy the ride.

I have purchased 3 of the SA's and had to return two of them because they were defective. They would disengage in the high range but the dealer replaced them including the return shipping charges. Maybe this dealer had a bad batch, not sure.

Without looking at the specs of the two hubs, the range change when shifting seems about the same for the two hubs.


BK, thanks for the info for the SRAM push rods.

Phil

 

[Vargas]

Thanks for the

Thanks for the answers!
Relations are:
SA 75%, 100% and 133%.
SRAM 73,4%, 100% and 136,2%.
Almost the same.
The quality issues you had with the SA scared me. It would be quite difficult to exchange something shipped to Brazil.
I'll keep my front derailleur.

 

[floridabike]

That's unfortunate as you

That's unfortunate as you mentioned, being able to shift while stopped and occasionally need a quick jump to a much lower gear and if you're climbing a hill is difficult with cassette gears. I also find myself changing the internal gears just to put the cassette gears in a better range and I wouldn't do that with the front chainring.

Maybe you can talk someone in the states to buy one and get it checked out. Once you get a good one it's good. I have about 1500 miles on one and no problems so far. It's an amazing hub for $75.

Phil

 

[Charles.Plager]

I also find myself changing

I also find myself changing the internal gears just to put the cassette gears in a better range and I wouldn't do that with the front chainring.

But that's exactly what you are are supposed to use the front derailleur for...

 

[thelonelycyclist]

Sturmey Archer CSRF3

I realise this is a year late but I have only just come across this forum.I wouldn't mind getting one of these hubs even though they are much more expensive in my country than America.I have a Pashley PDQ recumbent that uses the Sachs 3x7 system.My low gear slips under pressure when cycling up steep hills fully loaded so I think I should give this ago.As for the Shram dual drive I don't think they are available anymore.Has anyone ridded a fully loaded bicycle up very steep hills and had any problems with this hub?

Many thanks

Karl.

 

[mgpsmith]

DualDrive


Karl,

I have a 3x8 Dual Drive on a commuter bicycle I built on Surly Long Haul Trucker frame. That bike has been ridden loaded with perhaps 10 kg of computer, books etc.. not to mention my 90 kg corpus. Add to that the weight of bags, lighting, fenders, etc. and the entire rig is probably 120 kg. My commute starts with a ride up a 10% grade and has a couple of other good hills on it as well.
I went with the DualDrive because a local bike shop had a box of DD equipment (hubs, cranksets) that they gave me in return for the me buying the rims/spokes and hiring them to build wheels for the bike. I had to source the shifter and clickbox, and the biggest problem was locating the 10.5 x 1 mm nuts and the special position-lock washer they need (I ended up making that myself in my shop).

The DualDrive has given no problems in 7 years and a couple thousand km.

I would definitely recommend it. It's still listed on the SRAM website, and there is a lot of DD equipment for sale on eBay and Amazon. If you are buying new, consider the disc version. You'd have the makings of a great foul-weather bicycle.

Phil