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.

Riding urge

I got the urge to ride, but the weather lately has been horrible! Rain everywhere, mud, and dirt. Definitely not ideal riding conditions. Ugh. I only have a few more months of riding before the big event and I still don't have even half the funds I need to join the ALC. Ugh.

It's been a month

Wow, it's been awhile since I last rode. After just 3.75 miles I already felt like throwing up. It was probably b/c I didn't have much to eat for lunch and rode too hard. Lack of training made it a bit uncomfortable. But boy was it fun! I almost forgot how much fun it is to ride this thing!

Sped up to about 28 mph today on the asphalt. A couple slow moving cars ruined my speed though. Darn. Got the usual looks and kid's remarks,

"Wow, I haven't seen one of those bikes before!" shouted a little girl probably about 9 years old from her voice as I sped by.

Didn't see her face, but she was probably one of the most excited kids to ever comment on the trike. Sometimes I'm a bit hesitant to be too nice. Scared their parents might think I'm some guy from, "To catch a predator."

Just showered. Feels good.

Training success

My thoughts on how to best approach the ALC event as a recumbent rider is a lot more clear after experiencing this first training ride.

When I finally got to Mill Valley, there were about 25 people waiting there stretching and drinking coffee. Out of 100 participants for this particular training ride, that puts me in the first 1/4 of people to arrive. That's really great news.

There was also lots of space between riders. I was the first 5 people to take off from the starting line. Even after being warned by other riders, these first 4 people took the first wrong turn away from the Golden Gate Bridge. Not sure where they ended up b/c I hadn't seen them the rest of the day.

Immediately, riders would pass by me but it wasn't stressful. On the first hill, I made it to the top without getting passed up. Even on the bridge, people didn't really pass me up. One young rider did who later slowed down probably to get a better look at the trike,

"How do you steer with that thing."

"These handlebars," as I gestured using my fingertips to show him how it worked.

"That's sick." Later that day, another person would compliment with the same phrase.

For the remainder of the bridge ride, I was hanging with the group of 4 in front of me. No one else passed me. It was on the way back that loads of people - at least 10 people came up from behind.

When I reached the starting point, there were a ton of bikes. I think at least half the people were already on site.

CONCLUSION:
Although starting out in the first pack on this ride helped me and so did leaving the destination point to head back to the base, I'm hesitant to start in the front pack on day of the ALC. There will be over. This time there were 100 riders alongside me. On June 9th, there will be over 2,000 riders coming out of San Francisco. The front section will be insane.

To gain some distance over the course of the ride however, I have a couple strategies:

1. Leave early.
I am an early riser and I know most people don't want to start riding out at 6am. I'll sleep early the night before and start riding out from each of the camp sites early to give myself a head start while others are still resting, washing up or eating breakfast. This will buy me some more time if I need to rest later. It'll also give me more time to ride slower when I encounter hills. I'll also gain the benefit of less chaos. I'm guessing that around 9am, there will be a big group of riders leaving the campsites.

2. Take shorter breaks than the others.
Since I'm reclined the whole time, there's definitely less fatigue. I will take advantage of this and get an early start.

3. Don't take a break at the top of the hill.
I noticed people taking breathers after the hills. The hills are a pain in the butt, but it's either flat land or downhill that follows, I'm continuing. This worked for me during the training ride. While everyone took a break after the bridge, I kept going. They eventually caught up to me, but I needed the extra time to at least get a head start and maintain acceptable speed.


LESSONS LEARNED:

1. Take a break when I need it.
Though I'll be taking shorter breaks, I will need to take either the same number of breaks or more especially during hill climbing. I'll have plenty of people to accompany me. During this past training session, I developed a bad cramp on the inside of my thighs right before a big hill climb. It was killer. I knew if I kept going, I'd be in worse shape and regret it later. I took a good 10 minute break which was a great opportunity to check my tire pressure. By the time I was done, my cramp went away and I was ready to continue.

2. The lane's not too narrow.
My biggest concern for the ride is slowing other riders down. It's a single file line and I'm super slow on the climbs. Riders give me plenty of room as they pass me up which is great.

3. Support exists:
There really is support even during these training rides. One of the ride leaders kept his eye on me making sure I was okay. I'd catch up to him occasionally as he'd finish his breaks. For the long haul, I wasn't too far behind him. Another rider shouted,

"Good job rider!" as he saw me struggling up the hill. These few words do keep me going.

First training ride

ALC's having their first training ride for this next 7-day ride. It's tomorrow at 8am. After consulting with one of the staff earlier this week, I've decided to join the intermediate team for a 20 mile ride to Sausalito. It should be familiar territory, but I'm still a bit concerned about being able to keep up with the bicyclists.

I'll have a much better idea of where I stand with the upright bikes after tomorrows ride.