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Saturday, January 9, 2010

My best shifting recumbent drivetrain yet: Sram XX rear derailleur, SRAM TT-500 shifters, KMC DX10SC chain, Shimano cassette

Over 30 years of riding with derailleur drivetrains, I have used mostly Shimano systems. From Altus in the 80s to many years on Ultegra and Dura Ace STI 8spd on the road and Deore XT off road. I did spend a few years on Sachs 8spd Ergopower. Since getting bent (riding recumbents) in 2003 I have been on Shimano 9 and 10 speed systems, the only non Shimano parts being the occasional stock Bacchetta SRAM 9spd Rocket shifters, SRAM chains, and SRAM and Interloc Racing cassettes. Most of my shifters have been Shimano 9 or 10 speed Dura Ace Bar-Cons.

When I originally built my new Bacchetta CA2.0 in September of 2009, it was with a full Shimano drivetrain: Dura Ace 10s Bar Cons, Dura Ace RD-7703 rear derailleur, Ultegra triple front derailleur, Dura Ace 11-28 cassette, and Dura Ace chain. About 1000Km of randoneurring later, I needed a new chain. My brother John had been praising the KMC DX10SC, as the best bang for the buck option for 10s drivetrains, and the most durable for cyclocross. I ordered 3 in silver. You can also save ~20g per chain with the KMC X10SL.

Shimano rear derailleurs have upper jockey pulleys with over a millimeter of lateral play. This this is supposed to make them self centering, and less sensitive to cable adjustment. The shifters also have a certain amount of overshift built in to them to work with the upper pulley. This works well with Shimano chains. Unfortunately, the KMC chain is a bit shiftier. Unless you consciously try to minimize the amount that you over shift with the Dura Ace shifters, it will occasionally try to jump 2 cogs when you try to shift one. That is annoying, especially when you are going hard and have to deal with 2 jolts to your legs rather than one per shift.

After 2 weeks of this, I got lucky. Dana offered to let me demo a SRAM XX rear derailleur and SRAM TT-500 shifters. Cool! This was my first experience with a SRAM rear derailleur. Both pulleys use ceramic sealed bearings. They feel just as good as the old Suntour sealed pulleys I used to use on MTBs, and have no lateral play in either pulley. The RD is about 10 grams lighter than a Dura Ace long cage. Most of that is probably due to the carbon fiber cage plates. The shifters are about 30g lighter than the Dura Ace ones, and don't have plastic covers that can move or slip off. They don't have a friction mode though. You can save another 15g with the SRAM TT-900 shifters. Keep in mind though that they are carbon, and bar end shifters are one of the first things to hit the ground if you happen to knock your bike over, or worse. There are even SRAM bar end shifters with a return to center feature, no matter what gear you are in the lever is always at the same angle after the shift. I have not tried these but worry about not having any tactile or visual indicator of what cog I am in, and they have skinny levers, and they are heavier.

The shifting of this combination is the best I have ever experienced on a bent. It works very well with both a Dura Ace 11-28 or the much more affordable Ultegra 11-28 cassette. It just feels like there is better direct control of the what gear you are in. No build in play or overshift needed. I am still using a Ultegra triple front derailleur, as SRAM has nothing to compete with it, yet.

There are a couple of issues that I have had to deal within making this change:
  • Although the RD will handle up to a 36t cog, more than any current top end Shimano unit, and it has a long cage, it does not handle as much chain wrap. It was designed for those wide range cassettes and a double crank, not the triple that most bent riders use. Using the best current tactic for setting chain length with my 54/39/26 chainrings (make the chain just long enough that you can ride in the big chainring and biggest rear cog combo) I could only use the biggest 3 cogs on the cassette when in the small chainring without having the chain go slack. Besides the lack of a B pivot spring, the issue is the stop on the outer cage plate. It prevents the unit from taking unit more chain slack. I have run for weeks with that stop removed. However this means that if you have a flat and pull out the rear wheel, the cage will wrap a lot more and make it more challenging to out the wheel back on. I am going to put the stock stop back on and just live with more frequent chainring shifts on climbs. If you have less than the 28 tooth difference between largest and smallest chainring that I have, this will affect you less.
  • The rear shifter puts the shift  lever position in a different range than the Dura Ace shifter. it does not go as far down and forward to get to the small cog, but it goes farther upward to get to the big cog. With my shifters flared out at about 30 degrees from horizontal, this causes not issues with my hand when in the big cog. However, I have learned to adopt a new shifting technique when using the biggest 2 cogs: grasp my grip with my finger and palm facing upwards, and use my palm to move the lever. This works well. More varied hand movement to shift may be a good thing for those of us doing stupid long rides and races. 
  • Unlike the rear shifter, the front one goes farther forward when in the small ring. I have left a touch of slack in the cable to mitigate this. Even if I did not, its not really a problem.
  • There is no cable adjusting barrel on the RD. I have added a Jagwire Adjuster at the front end of the last piece of cable housing, which is easy to reach when riding. Easier than reaching the RD itself actually. 
  • You need Torx wrenches to work on SRAM components. I rarely need to do that on the road, plus in a pinch you can fake it with allen wrenches and screwdrivers. You can also replace the torx pieces with something else if you prefer. I am fine with them as they are.
Bottom line: In spite of the fact that I have plenty of Shimano parts around, I will be keeping this set up for far longer than any demo period. 

Update 011310: It has been brought to my attention that only being able to use the 3 biggest cogs on the cassette when in the granny ring might be an issue for some. I have done some more experiments. But here is why is does not bother me too much:

  • Chain bracing still affects how stiff a frame feels under pedalling forces, even on a CA 2.0. The bigger the chainring you are in, the stiffer the boom is. So, I tend to only use the granny ring for the gears it adds relative to the middle ring, i.e. the 2 smallest cogs. Once I get to the 21t cog I tend to shift to the middle ring, On flat rides, I ride almost exclusively in the big ring. 
  • A Shimano rear derailleur has some adverse behaviors when pushed too far beyond its total teeth capacity too. Instead of a slack chain, the spring loaded B pivot moves the derailleur so far back that the chain passing under the upper jockey pulley hits the chain heading forward. This causes some more drag and noise than a slack chain.
  • The slack chain you get with the SRAM rear derailleur does not seem to allow the chain to slap laterally too much, I have not been able to get it to hit the front fork or brake even in 26t chainring and 13t cog combo.
So what have I done to the bike? I took 1 link (1") out of the chain. This is now the absolute minimum chain length. I also experimented with the adjusting screw on the B pivot to take up a bit more slack. I did only enough so as to not adversely affect the shifting quality in the big ring. Result: I can now get 5 cogs down on the cassette without slack (down to the 17t cog). Again, this is using an 11-28t cassette. With a 11-32 or 36, the cassettes that this unit was designed for, you would adjust the B pivot even more which would help reduce chain slack too. I will say this though, not having a spring in the B pivot, the XX is less adaptable to different sized cassettes. If you want to run a 23 or 25 big cog on your cassette, look elsewhere. As a guy who prefers small gaps between cogs, like most racers, I am OK with a 10 speed 11-28 cassette, as long as its got a 14t cog!! ;-)

Update 01312010: As I have been asked a few more questions, time for an update. There is one more downside to a B-pivot that is not spring loaded. On a bike with a Shimano rear derailleur, you can put it in the big ring and small cog (as you should do every time you do a rear wheel swap) undo the brake quick release, then the quick release skewer on the wheel, and give the wheel a solid whack down and forward. You can have the wheel out in under 2 seconds if the bike is already in the right gear. That does not work with the XX rear derailleur. In fact if you do it hard enough you might damage the derailleur or hangar. With the spring loaded B pivot on a Shimano rear derailleur, as you move the wheel down and forward, it reduces chain tension, causing the B-pivot to move the upper jockey pulley rearward and downward and out of the was of the cassette as the whee exits. So, with my current B pivot adjustment, the upper pulley stays where it is until I manually move it back. Not what most experienced race mechanics are used to, and more time consuming and awkward without someone or something else to hold the bike. So I thought to myself, perhaps if I had the B pivot on the XX adjusted to where it needed to be for a 11-32 or 11-36, the cassettes that it was designed for. Well I cranked the B pivot adjuster all the way out, and its still an issue. On such a big cassette I would also be using a longer chain, but on this derailleur, that would make no difference in the position of the upper jockey pulley, so I did not try it.

I still love the way this set up shifts thought.

Also, you may notice some product links to specific vendors in my posts here. Those vendors give me a small commission if you click on the link and buy the product. So, if you cannot buy these parts at your local bike shop, please use my links to get them from Bent Up Cycles, or Amazon.  Product links with pictures:

Wednesday, January 6, 2010

Reflective vest for randonneuring and night riding thats aerodynamic , light, and stylish.

I have been doing brevets now for a few months, a few that involved night riding. The rules say that "During hours of darkness or other low-light conditions, all riders must wear a reflective vest, sash, Sam Browne belt, or some other device that clearly places reflective material on the front and back of the rider."    I have used some cheap running vests, with velcro and mesh, but they flop around and get caught on stuff, and they are not aerodynamic at all. I also don't like velcro with other stuff in the laundry, or catching other stuff in my bag or jersey pocket.  On my last 200Km brevet, that started in the dark, I tried one of these: Nathan Flash L.E.D. Reflective Vest (Small / Medium, Yellow). Its Lycra!! It stays put, and its aerodynamic. It also takes very little space once you take it off. I bet its the lightest solution too. A note on sizing: I am 185 pounds and wear mostly size L, but I got a S/M in this vest and its perfect. If your chest is over about 46", get the bigger one. Its very elastic though, and the S/M was only slightly loose on my 100 pound GF. I think it comes in white too, but the yellow went well with my stylish PCH Randos Kit.

PCH 200Km Brevet Ride Report 010210

Here we go, blogging!!

I did my first full brevet series last year (200Km, 300Km, 400Km, 600Km), all with the PCH Randonneurs.  Although I don't think I can fit a full series in this year with Team RAAM and Battle Mountain on my schedule, I really could not miss out on the first 200K of the year. Its all in my back yard. Fresh brick oven pizza at the finish control was a nice enticement too, and of course good weather was scheduled.

This time the registration list was published before the event, so I could see who was coming. Most of the brevets I have done have been pretty lonely.I was happy to see Wade Baker signed up as he finished 30 minutes ahead of me on the 300K last year. I was also looking forward to seeing how I fared relative to Jim Swarzman, who has had some good results and sure looks like a fit rider. Dan Crain was another rider I hoped might help form a front group, but he switched to a tandem for this ride. Given the course profile, 4000' of climbing in the first 100Km,  I figured Wade and Jim would get around Lake Casitas a bit in front of me, and I would be chasing and hopefully catch them sometime on PCH on the way home. I was curious to see how this would play out.

Java Kai opened early just for us to register and get a morning fix. . If you are ever in Moorpark and need a coffee or smoothie.......   I think I must have missed several people I wanted to say hi to before the start. Wade and I apparently can not recognize each other without helmets and sunglasses on. He thinks I am Ron Smith, and I was not sure if he was who he was. I think one of my neighbors on a Bacchetta, Ed North, was there but I did not see him, nor Bill from Oregon. I fired up my video camera for the pre ride meeting, but the video camera must not have shut off properly and the video will not play. Next time.

At the start, I asked Wade if we were going to go hard. He said no, he was going to draft me, but who knows if he was kidding or not. We left the start in Moorpark just before dawn, a few minutes after 6:30am. The first 3 miles are slightly downhill, followed by five miles that go up 650'. I like to keep my power at about 200W on the flats and under 250W on the climbs for 6 hour plus rides. At 200W I was slowly riding away from the rest of the 65 riders. I am riding a Bacchetta CA2.0, with Hed Jet9 C2 wheels, so I have a bit of an advantage aerodynamically.

As I started climbing Grimes Canyon Road, I kept an eye in my mirror for company. As I got to the top of Grimes, 2 riders had closed most of the gap that I established on LA Avenue. Now there was a bit more flat before the final 200' climb to the top of Stockton Road. I got to the top of Stockton Road, and the first secret control, just before Wade and one other rider. I had seen them coming and picked up my power just a bit to make sure I got to the control first and would not have to wait and then have to re-pass them on the fast descent that followed. As we were all stopped I joked,"Why are you guys breathing so hard?"

After that I was off on fast roads, and did not see anybody behind me. I was keeping a close eye out for the right turn on Berylwood Road, as most of my training routes in the area go straight past it. I was riding without a GPS, or even a convenient cue sheet, so I was sure that would be the turn I would miss. I got close to the second section of LA Avenue and hit the second secret control. I chatted quickly with Lisa, got my card signed and took of again. I was still wearing 2 layers of arm warmer. It was supposed to be 45F at the start, but it was warmer. I did not go for the full finger gloves or cap under my helmet it was so warm. Once on the road though, there were sections were it felt like it was in the 30s! Still no pursuers in sight. I got all the way to the corner of Wells and Foothill in Saticoy alone. Then I spent some time looking for the info control. I goave up and rode on. Then after a minute I turned around for another look. It had to be there! As I was finishing my second look, Wade, Jim, Dan's tandem, the other fast tandem, and a few other riders showed up. We all quickly agreed that the info was not there and that we would mention something about Bingu the lost dog we saw on a sign.

As we left that spot, it was very gradual climbing, followed by some fast descending. As I roade away fron the group, Jim says,"See you on Casitas." That was my guess too. Wrong! 3 minutes later I stupidly ride through some fresh glass and immediately loose all air in my rear tire, a Conti 4000S. I pull over the the left side of the road where there is a curb to sit on, and try to signal to the riders coming. I think they must have been paying better attention than I was. I got to work, found a gaping gash in my sidewall, and booted it with a piece of Michelin Pro3 Race casing. I did not bring any CO2 for this ride, so I had to pump it up with my hand pump. Willie rode by and asked if I needed anything, and about 30s after that I was on the road again, chasing Willie and Dan on the tandem.

Now, I had been using Hammer Espresso Gel for fuel up to this point, and I am sensitive to stimulants, so I was pretty pissed at myself and in a chasing mood. Willie only had a 53x13, compared to my 54x11, so I caught him on the descent into Ventura. I passed Dan in there too, a few times, as I lose a lot of time relative to him at stop signs. Willie never really got a good draft off me, but we were together through Ventura and onto the bike path to Ojai. Its a very gradual climb, and I was riding just a bit faster than he was. I later found out that his bladder was even closer to bursting than mine at that point, and he had to stop. I passed a few DF riders on the path, but I do not know if they were Brevet riders, I also lost more time to cyclists and roller bladers at the stop signs. As I got of the path and up to Santa Ana Road, I caught the fastest tandem. They had the good sense to get on my wheel all the way to the Corner Market control. I have to admit that I wanted to let them pull a bit, but my whole digestive tract was about to explode. I wanted to be first into the bathroom I remembered was in the back of the market.

As I got to the Market, there were four riders there getting ready to go. I did not even see them, I was racing for the bathroom. It was worth it, no line! I do have to apologize for the state of the air after my departure. No fan. Boy, did I feel better though!! I paid the cashier for my water, and had to ask about his outrageous accent. He's Syrian/Guatemalan. Thats a mix I have never heard before. I let him know about the other 55 riders that would be asking for receipts in the next few hours. I got back on the road just before the tandem, after offering them my left over water. Once on the road there was no one in site. Its 8% for a bit here getting up to the lake, and very pretty once you do.

Once I hit Casitas Pass road I started trying to figure out how many people were still ahead of me. Problem is I had not kept an eye on who had passed while I was flat fixing. Oh well, just keep the power steady. I passed who I later learned was Jim Olsen on the way to the little climbs around the lake. I passed him in one of those typical recumbent aero advantage situations, on a slight ride following a steady downhill. I fully expected him to come back to me on the climbs, but the espresso gel was working overtime. I allowed myself to exceed my 250W limit, as I figured there was plenty of descending to recover on, and these were the last real climbs on the course. I also had been eating every 20 minutes, and trying to put down over 250 calories/hr. I am getting better about eating enough, and I figured that would help me get away with pushing it a bit.

As I got near the top of the highest climb of the ride, about 1200', I could see the last section of road to the summit to my left. I kept watching the piece of road to see if I was near anyone else. I got lucky! I saw Wade's TdF climbers jacket! I stered counting seconds until I passed that spot. 90 seconds. Come to find out later, Jim was 20 seconds behind him there. I came over the top and kept the power up until I was doing over 40mph. I let it run on the descent, but not enough to scare myself. I have learned the value of relaxation on long rides. The last climb on this section comes halfway down the descent, a 300' winding affair at 8% or more. The top of it opens up to a view of the Pacific. Very nice. There were quite a few riders and groups heading the other way for me to wave at. Somewhere after the turn onto Rt. 192, I passed who I later learned was Bruno. This again perfect recumbent terrain, slight downhill with a headwind.

Approaching Carpinteria, I saw a small group ahead, and Wade in it. I was about a second off the back as we approached a stop sign before Linden Road. That left me a 15 second gap to close, which I did by Linden. Jim or Wade commented,"Oh look, he's caught us already!" I went a bit too hard on the climbs, but that was nice reward. Wade and I stopped at the light at Capinteria Ave, then went to the 76 station to get receipts, and Jim disappeared, to an ATM according to Wade. I left the 76 before Wade. He was drinking a V8. That what I should have been doing! I had only a few Saltstick Electrolyte Caps left, the rest of what I had was Hammer Endurolytes, and they do not have enough sodium for me if I go hard. I also should have grabbed a fresh gel flask from my bag and put it in my jersey pocket. Oh, and I should have re-applied sunscreen. I was in a hurry to get out of there. As I left Jim appeared in my mirror and we chatted for a second. He bid me adieu as the terrain from there on was flat and fast, except for the 200 foot climb out of town to the top of Rincon Hill Road. he was close enough to get on my wheel for a while. On the descent of Rincon I kept an eye in my mirror. There is a bridge followed by a 90 degree turn over bumps that is usually sandy near the bottom, and I did not know if he knew the roads. Once I saw him exit the turn upright, I put my mind on enjoying some 25mph+ cruising on the 101 freeway and highway 1 back to Ventura.

What I always forget is that once you get on the 101 and then old Hwy 1, the pavement is pretty rough, especially at 25mph+. My stomach got a bit upset. I have a new tool to fight that though. I try to relax. I think to myself, hey, I am riding my nice bike, and in sunny Socal. 15 years ago a January ride would have been in the snow, and 7 years ago I could not even ride a bike anymore. This helps me relax and enjoy the ride. The chop on the Pacific was impressive. Coming into Rincon Beach I had to ride out near the yellow line a few times to avoid the spray. going through Port Hueneme I was doing over 25 most of the time, on smoother roads now. I was remembering the 400K in September, when I first discovered I could do 24mph on this bike with 200W. Fast. Well It eventually dawned on me that if I am doing 26 or 27 at that power level, I must have some tail wind, and there is a 90 degree turn in the course coming.

Well after turning NE out of Pt Mugu, I got hit with a nice cross-head wind. I was dong 16-19mph now. The 90mm deep front wheel was quite manageable though. I also finally sopped and re-applied sunscreen to my fragile face. Then I realized no way could I get to Moorpark on one Endurolyte without cramping, so I stopped at my favorite Mobil station in Camarillo for a bathroom stop, and some V8. I also finally shed my arm and leg warmers, as I must have been over 75F! Knowing the area I just assumed that once I hit Camarillo, there would a nice tailwind up Santa Rosa Road, and I could come in under 7 hours. Nope. That has to be the first time ever I have had to fight a headwind up the Santa Rosa valley. I could still ride 250W+ on the steeper grades, but there were really only 2 left, the one on Moorpark and then the short grade on Tierra Rejada, after that its all 30-40mph to the turn to the finish control and PIZZAAA!!!!!

I finished in 7:10 elapsed time, my powertap says I spent 6:40 of that riding. I thought I spent over 5 minutes on my flat, but my powertap was still on afterwards, so maybe I got it done quicker. If I had enough good electrolytes, and if I took the time to take care of all my needs at the controls I could have saved at least another 10 minutes. Still need to plan better to get really good at this.

Great spread of food out when I got to the Jones'! I got my pick of pizza toppings, lots of other munchies.... It was really nice to have some good food and a place to relax before going home. So just as I am going to leave, Greg tells me my rear tire is flat, again! I catch a ride with Jim S and Nicole to my car and come back and fetch my bike. The next day I would discover not 1, but 3 gashes in my rear tire sidewall. 1 was booted, but the other 2 should have blown out too. Glad I replaced the latex tube with butyl when I flatted on the road. Good thing I noly put 100psi in with the hand pump too. Get this though: the second flat at the Jones' was from the edge of the boot chafing through the tube. Wow, I did get lucky!  Next time I'll just bring a spare tire, like I did on the series last year.