Biggest bike in the world?

That's just crazy

Alternatives to the CS-RK3

Perhaps the SX-RK3 will work from SJS Cycles in the UK. I'm not understanding the specs from the website very clearly, but it sounds like it's compatible with a freehweel and a disk brake! Sounds good to me! A price of $188.33.

There's a TF-RS3 that is designed for trikes! Sounds like it takes a freewheel but no brake. Hmm, at $134.27, I think I'm willing to sacrifice the rear brake.

With all these hubs, I'll still need to purchase a new wheel though since the mag ones aren't hub interchangeable - or least I don't think they are.

CS-RF3 accepts a 8/9 speed cassette but is not disk-brake compatible. This is from the Sunrace blog. Same as the ideal CS-RK3, but it's not disk brake compatible.

The search for a Sturmey Archer CS-RK3

I called up Bike Stop and what a friendly company! Jeff, the rep who answered my call was super nice and look for some alternative products that may satisfy my need for a 3-speed hub that allows a disk brake and is also cassette ready. Unfortunately nothing. Jeff had a great attitude though and was friendly even though his company wasn't able to get me what I was looking for.

I did learn from him though that Sturmey Archer commonly releases only certain products in certain parts of the world. I may have to contact their Netherlands office to get what I'm looking for.

Good news! I came across the Sunrace blog and they have a picture of the CS-RK3! It's a shot from the 2010 Taipei International Bike show.



There's a guy on another forum that has his own shop that sells these! I'm contacting him ASAP. The source is here and I'm getting if my BROL deal doesn't go through.

More Shimano Nexus info

I'm looking at alternatives to the Sturmey Archer CS-RK3 and found the Shimano Nexus Inter 3. Problem is that this unit nor any of the other internal gear hubs in the Nexus lineup have the ability to include a cassette. I just got off the phone with one of their reps and they unfortunately were able to confirm that. Too bad. Looks like Sturmey Archer's the only company that allows an internal gear hub to be mixed in with a cassette. Brilliant.

I'm continuing my quest for a supplier than can get me this unit! Worse case scenario is that I'll have to sacrifice a rear disk brake for a coaster brake. At least I'll have a rear brake though.

Sturmey Archer setup

The new KMX F3 which only has 3 gears uses a Sturmey Archer internal gear hub. I researched the brand and it's cheaper than the Shimano's by a little bit. Looking through their website, I found the another 3-speed version that allows both a cassette and disk brake. It's the CS-RK3 model.

No need to sacrifice anything if I use this! Instead of using my current Megarange 7-speed freewheel, I can get a Megarange 8-speed cassette which gives me the following gear inches.


Amazing! Gear inches is 15.7GI-86GI using a 38T single chain ring up front. This is all thanks to the ability to utilize a cassette with the internal gearing hub. Most internal gearing hubs don't allow a cassette nor freewheel to be mounted.

That's pretty much perfect! If I'm willing to sacrifice a bit of low end for a bit more high end, I can get up to 90.5GI's for the highest gear using my existing 40T single chain ring. No need for derailleurs or anything and the best part? The price! I have yet to find it, but it should be priced under $200!

The hardest part is finding a place that sells this! Ugh! Sunraceusa.com is Sturmey Archer's dealer. I'm waiting for a return call to get accurate pricing and availability for this product. So excited!

To Do List

There are a few things I need to do to prep for the ALC ride that are making me nervous:

1. Get donations up!
2. Acquire a box big enough to hold the trike.
3. Improve my gearing.
4. Improve my heart rate and endurance abilities.

And my plans for each?

1. I need to contact my family, friends and old colleagues again. So far I've printed out all the current doners' names and stuck them on the trike like promised.

2. The box can come from KMX or a local bike shop. I just need to contact them. I prefer getting it from KMX, but need to determine if there's anything else I need to order from them. I'd like to keep the shipment to a single package.

3. Andy from BROL has offered to help me with my gearing. He'll provide the KMX Shark to hold the derailleur, the chain rings, shifter, some wheels and other components that will prepare my trike for the ride. I need to confirm a measurement and he needs to confirm his availability for next month.

4. This is just a matter of getting on the trike and riding. Should be fun. I just hope the weather gets better.

First ride in a long time

I hope to ride today. Angela's got her massage scheduled for this afternoon and after my weekend gig here I plan on riding through Golden Gate park, no matter what the weather is like. As long as it's dry, I'll be out there. I really need to get some miles in. I have less than 100 days left before the ride starts!

Getting nervous? Definitely! As long as I plan everything out, I should be okay.

X-Class 3 chain ring setup with SRAM Dual Drive

It turns out the X-Class had two styles. One had two chain rings, 22/42 and the other had three, 22/32/42.

This is how the gear chart would look like. However, it would never be possible. The SRAM has a 30T limit. It doesn't support chain rings smaller. It's interesting to see the combination though.

SRAM Dual Drive a failure?

I've heard horror stories of the unreliability of SRAM's Dual Drive product. This scares me b/c one guy completely lost all his low end gears midway through a ride:

http://www.bentrideronline.com/messageboard/showthread.php?t=60147&highlight=sram+dual+drive

I can't imagine what I'd do if that happened. That would be horrific. Stuck at the bottom of a mountain with failed gear unable to get up the hill with 6 more days of 100mile/day rides would be a huge disappointment if not impossible mission.

The unit is probably much harder to fix. The mechanics on the ALC ride wouldn't want to touch it. Perhaps the standard 22/42 compact double that the KMX X-Class offers would be the way to go.

Reading through the forums further, I found that the SRAM Dual Drive has a limit of 30T chain ring. That means I cannot combine it with the 22T from the X-Class setup. Let's see how the gear chart would look with a 30T ring up front.

Low gear is still 12GI's. That's far from the 8GI's I originally found with a 22T chain ring up front, but that's not so bad. 8GI's is ridiculously low. The lowest GI I've ever heard recommended anywhere was 10, but mostly 12. 8 is unnecessary so I'm not really disappointed.

Gear range with this setup is 12.1 - 92.5

After tinkering around with the charts, I found a new configuration that might work better. I used the smallest and largest chain rings available from Sinz (cheap chain ring supplier) and picked the exact middle number for the center chain ring and the chart came out like this.

GI range is 13.7-111. I can comfortably start in 2nd or 3rd gear w/o engaging the SRAM Dual Drive using the 41T chain ring. I expect to do most of my triking in this setup which would be ideal since the efficiency should be best for the SRAM Dual Drive in this configuration. It's very similar to my existing 7-speed setup.

I would engage the SRAM's high gear for fast flat land and switch to the 48T chain ring while in SRAM's high for down hills rides. As I'm walking myself through this, I find that there will be a lot of double shifting. Engaging the Dual Drive while in the 41T chain ring pops the GI's up by 36%. To get a smoother transition, I will have to downshift my cogs by one gear every time I engage the Dual Drive to a higher gear effectively going from 69.6GI to 80GI's. That's much better than going from 69.6GI's to 94.8GI's.

This gets really complicated! Let's see how a compact double crankset would work. The chart is the same minus the 41T chain ring.


The jump from engaging the SRAM Dual Drive is still extreme but that's because it's governed by the ratio of the internal gears. There's nothing I can do about that. As expected the GI range has also remained unchanged. It's easier to think about though. I'll spend most of my time with the 48T chain ring which would be used for flats and minor slopes both up and down with the Dual Drive disengaged.

The Dual Drive would only be put into high gear for extreme down hills. I will only pop the Dual Drive into low and bring the chain ring down to 34T during extreme climbs. There we have it.

No rear brakes!

The Catrikes don't have rear brakes and neither do many of the other models. Having one is what makes the KMX stand out. I just realized though that I'd have to sacrifice the rear brake in order to install the SRAM Dual Drive. I don't believe a disk brake can be installed on it. I'll have to call Ashley over at Utah Trikes to find out.

I got an email back from them and apparently there's an option to add a rear disk brake. The option costs $80 though!

Conclusion for gear design

It's been almost a year since I've started analyzing gear options. I need to make a decision by the end of next month in order to give myself ample time to practice, get used to the system and other preparation for the ALC ride.

The Schlumpf is too expensive and weighs too much. It's no wonder most people don't have it. The system is pretty cool though and doesn't give you any gears you won't use. There's good points and bad points, but overall for my particular situation, the Schlump comes to the bottom of my preferred list.

1.
2.
3.
4. Schlumpf Mountain Drive

So now the choice is between the SRAM Dual Drive and the X-Class setup. I feel like I would eventually want both, but which one would help me on the Aids Life Cycle ride? This has to be an objective question and the answer is?

1. SRAM Dual Drive and X-Class combination
2.
3.
4. Schlumpf Mountain Drive

Well, the X-Class setup is way cheap compared to the other options. It's almost 1/4 the cost of the Schlumpf. Big plus on that! It also provides me lower gear inch for hill climbing than the Dual Drive would - at least with a 40T front chain ring.

Final decision?

1. SRAM Dual Drive and X-Class combination
2. X-Class stock setup
3. SRAM Dual Drive
4. Schlumpf Mountain Drive

Test riding Catrikes

I scheduled with CVC San Francisco, a local recumbent trike dealer to test ride 4 of their models.

Option #1: X-Class setup

I might have posted this before, I'm curious how my new options compare against the stock X-Class gear range. My cheapest option of getting lower gears would cost me $250 and these are the results. The chart looks like this:

This mod would give me one higher gear and three lower gears. The gears are significantly lower than my current setup and still even better than using the SRAM Dual Drive.

I can't help but to think what would happen if I combined the two. Hmmm, now that would be interesting. Best of two worlds? Let's see.

Combining both systems would give me a range of 8.9 - 97.1! That's insane! I could probably climb a wall with that setup! That would be pretty ideal, but it would cost me $650+ to get there. That's still less than the installed cost of the Schlumpf drive and would weigh less overall. Two points against getting the Schlumpf. I understand the Schlumpf drives weigh in excess of 10 extra lbs! Do I really want to carry around a 52lb trike? Uh, no!

38T chain ring on an SRAM Dual Drive?

I'm curious how swapping the 40T chain ring for a 38T would effect the lowest gear. How much lower gear inches will I get from the replacement? Would it be worth it? Let's take a look.

I saw the preliminary gear chart and thought, "Why stop here?" So I decided to tap on another couple chain ring sizes to see how low I could go and what the effects would be on the high end Here's the side by side comparison of a 36T, 38T and 40T chain ring on the SRAM Dual Drive setup.

Tough choice. I love the idea of being able to go under 15GI's, but that comes at the expense of one less high gear than my stock setup. I'm liking the 38T chainring.

SRAM Dual Drive

During my research for more options on getting lower gears in prep for climbing hills, I discovered the SRAM Dual Drive system. Utah Trike sells it and it happens to fall in between the two prices of my other options:

1. Add a 3 chainring setup at the front boom - $250
2. SRAM Dual Drive - $400
3. Schlumpf Mountain Drive - $700+50 (shipping/tax/blah)

Q: So what's the SRAM Dual Drive?

A: It combines a 3-speed hub with a 9-speed cassette. So what does that mean? It's a single unit that replaces the front chain ring as well as the rear cassette or in my case, a freewheel. It basically relocates the front would-be chain rings to the rear in the form of an internal hub. The cassette is added on. If installed, I'll get 3x9 = 27 gears instead of my current 7.

The cassette is actually a 9-speed with the following cogs:
11, 13, 15, 17, 20, 23, 26, 30, 34

This is how the gear chart looks like. The middle column shows my current range. It's not completely accurate b/c my current freewheel is only 7 speeds while the new cassette will be a 9-speed.Looking across the chart, I see that I'll be getting 3 lower gears! It's significantly lower - 16.1GI's instead of 22GI's.



Another effect of going from a 7-speed to a 9-speed is that the transitions between the gears will be a lot smoother. There's no jump from second lowest gear to lowest gear like there is now.

In addition to the lower granny gear, I get two higher gears for downhill speed! 78.3GI and 92.5GI is a big enough hop from the existing 67.9GI's. That gives me a 36% jump!

In my previous posts, I noted that 88GI's would be my ideal high end. Having a gear higher would be even better. What I'm most excited about though is the 16.1 lower gear.

Another advantage to this system is that less can go wrong. The system is definitely more complex, but there's less to mess around with. Everything is internal and gear changing is all done from the rear. Nothing happens up front.

The kit comes with a wheel! Since I need a back rear wheel anyway for backup, I won't have to buy an extra. The kit also comes w/the shifter, derailleur, cable, hardware, grips. Sounds really good! Hmmm.

Thank you donors!

I had promised to print out the names of all who are donating to the Aids Life Cycle on my behalf to be pasted on my trike. Here's how the collection looks like so far.

Thank you! To make a donation, please click here:

Donate to ALC on behalf of Brian

Typical road bike gearing

I'm curious what my companions will have on the ALC in terms of gearing. I'm reading that road bikes have something between 18-104GI's by utilizing a 11-34T cassette across a 22/32/44 chainring setup.

I did some further research and found a general idea of what different types of bikes can be expected to have:

Mountain Bike: 18-103GI's
Road Race Bike: 43-127GI's
All around: 20-90GI's

My KMX Tornado: 22-67.9GI's

Somehow I'm still a lot faster on the downhills than most DF bikes I've ridden with. They're not mashing down the hill though. I suspect my speed has something to do with my bent being more aerodynamic. I'm no physicist but theoretically, I would need less high end gear inches to achieve the same speed since I can take advantage of the momentum and aren't fighting as much resistance.

From experience, I think 2 extra gears up top would be ideal. Assuming there's a 15% increase in GI's per gear, that would put me at about 88GI's - far from the 100GI's that I original thought I may need/want.

This is good news. I can sacrifice quite a bit of high end gears to boost the low end. Calculating the same logic that I used for the high end gear to push the low end 2 gears down at 15%/each , I end up with around 15GI's on the low end.

A boom and chain ring setup from the old KMX X-Class satisfies the low end, but not the top end. The top end would pretty much remain unchanged whereas the low end is improved fairly drastically. My lowest gear inch will be 12.1 instead of 22.0. I'm certain I can climb any hill with that.







While the old KMX X-class gearing is supplied by a 42T chain ring, the newer setup from the KMX Cobra (mountain climbing version) is equipped with a 44T. I made this chart to decide whether it would be worth going for the newer Cobra setup or just stick with the available X-class one. I suspect the X-class one will be cheaper. It's priced at $250 shipped for the boom, derailleur, and chain rings.



I'm still considering the Schlumpf drive, an internal gearing system but that's priced at way over $250. It's more like $850-900 by the time it's completed. It involves not only acquiring the components, but customizing it and having it specially installed. The Schlumpf drive acts as a double or quadruple chain ring w/o a derailleur. It's typically used on geared unicycles. Who ever thought unicycles could be geared?? Well, they can and Schlumpfs technology makes it available....at a price - a steep one.

Looking at the numbers, this is pretty ideal! I would get virtually the same low end gears with high end topping out at 94.5GI's. If I got this setup, I wouldn't want to go further. I could commit to keeping it and not modding it any further.








The previous option of replacing the stock boom components with a new one from another KMX has an obvious price attraction, but I think I'd still have an urge to eventually increase the high end. With nothing else available, I'm topped out.

How practical would a higher top end be though? I think I've already gone 34mph. My goal had been 40mph, but I'm thinking that's just a ridiculous speed to go unless it's on a closed course, but even then it wouldn't be worth the extra cash it would cost to get there.

I'm still on the fence, but need to make a decision w/in the next month. I need time to get the components delivered, installed and tested before the ALC in June.