Ritterview

Aha, Shimano saw this thread, and relented. From Bike Radar:


Shimano Ultegra 6800 mechanical groupset - first look

hamster

According to my usual bike calculator https://www.kreuzotter.de/english/espeed.htm it takes a team of two riders averaging 620 watt between themselves to hit 36 mph on a tandem on flat terrain.

I took a look at the GPS log from a recent circuit race by one of our local racers (pro 1/2 category, crazy fast). He hits 35 mph pretty regularly and he hit 38 mph several times several times during the 2-hour race. I can see him needing a 53/11.

Dean V

Is there really much difference in how 105 works compared to Utegra or even Dura Ace? Obviously the finish isn't quite as nice but as far as actually riding the bike is there anything in it? I had 9sp 105 on one of our tandems and I thought it shifted, braked, etc as well as the higher end stuff I have.

Sprout97 

It was always my understanding that it was mostly an issue of weight reduction moving up through the Shimano hierarchy. Shift action was supposedly a noticeable improvement between same-year 105 & DA, but not so much going up/down from Ultegra. My ex-Specialized Roubiex was 105 (except for the Ultegra RD) and was a bit smoother shifting than the 4yr older Speedster. Part of that was the trickle down thing, and partly the half bike was a compact/10 vs. the tandem's triple/9.

Going into a makeover of our Speedster, I weighed replacing my original 6503 triple with a R601/602 or DaVinci cranks, but in the end, kept the 6503 and replaced the worn out Octalink V1 bb. Ironically enough, the new bb is a 105. Go figure.

merlinextraligh

It's mostly weight and finish quality. But there are little things that add up to improved performance as you go up the line.

For example 105 uses sleeve bearings in the derailleur pulleys; Durace uses sealed cartridge bearings. The FD is stiffer for crisper shifts, the shift lever requires a shorter throw, etc. All small points, but they add up to the overall feel and perfromance of the group.

That said, all of the groups have gotten better with time. The latest generation of 105 is likely as good or better functionally, than 1 or two generation old Dura Ace.

We replaced the Dura Ace 7800 RD on our tandem, with an Ultegra 6700 RD (because long gage 7800 RD's are hard to find now) and the newer Ultegra RD shifts as well or better than the older Dura Ace.

waynesulak

The differences between the component lines also varies by individual component. For example merlinextralight mentioned the use of bushings vs bearings which is a real qualitative difference. On the other end of the spectrum are chains and cassettes. The only difference between an all steel Ultegra 10 speed cassette and the 105 is the finish and appearance. Same steel and same tooth profiles. No performance difference.

Sometimes the lower group component might serve better for a users purpose. I sometimes use a Tiagra 12-28 10 speed cassette because it is not offered in the higher lines. There is a 80 gram weight penalty compared to a Ultegra cassette because the Tiagra uses individual cogs riveted together as a unit rather than a light weight spider. Same steel and tooth profiles so it shifts just as well and gives me the exact gear ratios I want which are not available in 105, Ultegra or DA. When I want a 12-25 cassette I use 105 or Ultegra. The 105 weighs and shifts the same as the Ultegra 12-25 but finish is not as nice.

It appears to me that a major driver in the tech advances is product line differentiation. Now that DA and soon Ultegra are 11 speed it limits substitution of lower level 10 speed components by the user.

twocicle

With the advent of Shimano's shift to yet another proprietary 4-arm 110BCD spider of which the arms are not equally spaced (not sure what term to use... "offset", "asymmetric", "non-uniform"?), it will be interesting to see if other manufacturers will follow suit.

If Shimano does eventually produce a new version of tandem cranks with that same spider format, will Gates produce a compatible timing ring? Or, will there be oddball adapters for mounting standard 130mm 5-arm rings to the new, non-uniform 110mm 4-arm? Time will tell, but immediately there is no solution for anyone wishing to utilize Shimano's 11spd cranksets and a Gates belt drive (same-side or otherwise).

waynesulak

Everyone bemoans the nonstandard items on Santana tandems and rightfully so.

We should support vendors that avoid "proprietary standards" (seems like an oxymoron to me) and vote with our $$ for those manufacturers that use industry standard compliant products. True standards help manufacturers like Gates supply the low volume tandem market with products that will work on most of if not all tandems. Without true standards it is not be economical to enter an already very small market.

twocicle

The chain pitch (link length) did not change from the standard 1/2". It is only the width that was changed from the 10spd 5.88mm to 5.5mm for the 11spd chain. One of the easiest ways to tell the diffs between chains is to go look at a 3rd party vendor such as KMC's "chain choice" selector and compare the diffs there.

According to guesswork from Lennard Zinn and other posts online, people have had success mixing 10 and 11spd components. So, the good news is that it appears we can still use our existing 10spd cranks with the new Shimano 11spd chain and shifters and it should not be necessary to upgrade 10spd tandem cranks just to get the 11spd cassette gearing. I believe that with the 11spd cassette you would still need the 11spd shifters in order to get the correct amount of cable pull required for that cassette spacing.

One additional irk. At the moment, KMC does not have an 11spd Missing Link listed as compatible with Shimano chains, and the 11spd versions they do have (Campy) are non-resuable and state those versions need one special tool to install and another tool to remove. Up till now I've enjoyed using the reusable 9 & 10spd Missing Links (very convenient for chain removal when cleaning or travel) without needing any tool other than maybe a pair of needle nose pliers. Reviewing KMC's tools, those appear to be simply narrow nosed pliers, so other than having one for removal, likely only that one is needed (for install, simply pull on the chain). Hopefully there will be more selections available in the future.

akexpress 

No offense but I like the innovation that is occurring in the bike industry and some of it trickles down to tandems. We can vote all we want to with our dollars but it probably doesn't matter because we are such a small small niche market. Carbon and magnesium tandems, belt drives, electronic shifting, disc brakes, STI shifters , 11 speed cassettes, power meters, gps bike computers, helmut communications systems, tubeless tires, PBO spokes, carbon rims tapered headsets are just a few recent innovations that i can think of. There are of course changes that are driven strictly for marketing purposes that make it difficult to integrate for tandem usage.

mtn.cyclist

That said, all of the groups have gotten better with time. The latest generation of 105 is likely as good or better functionally, than 1 or two generation old Dura Ace.

We replaced the Dura Ace 7800 RD on our tandem, with an Ultegra 6700 RD (because long gage 7800 RD's are hard to find now) and the newer Ultegra RD shifts as well or better than the older Dura Ace.[/QUOTE]

So true...I used (long time ago!!) to ride only Dura Ace or Ultegra on my single bikes. Now my 105 equipped single performs much better than the old high end stuff. I guess it is somewhat relative.

waynesulak

I like innovation and most of what you mention above as well. Big changes like carbon, magnesium vs aluminum and steel are well worth a try and actually pretty compatible. All the standard components work on Pateka and Calfee frames because they are built to acceptable standards. Belt drives work on standard spiders. All that is great and standards like 130BCD and 110 BCD allow companies to innovate with really new products like belt drives or years ago carbon forks. Mountain bikes with big wheels can take off easier because they used the standard 700C size wheels rather than slightly different rim size.

I was referring only to small changes like taking an old standard like 110BCD changing it just enough to make it incompatible. This was done by Campy years ago and now Shimano follows suit. Campy's change was so small that a little grinding on a non Campy chain ring can work around the problem. Shimano did a more through job of hurting the small companies that have to follow the market leader. Little or no innovation just change. Same with the Shimano's granny gear BCD vs the standard 74BCD. The ultimate example is when Shimano simply changes the styling or shade of there components to make the prior year's stuff seem obsolete.

The dollars buying things like granny rings (including non tandems) may not seam like much but it was enough for Shimano to change the design of their triple in an attempt to capture it.

WPH

What he said!

Likely Shimano would prefer to be the only vendor for parts we all need when stuff wears out. In general their kit performs well enough, but its better to have a number of options, as a consumer, we might be prepared to pay more for better performance, or need to pay less to stay on the road.

DubT

If I were building a new tandem today I would look at SRAM 10 speed 11-32 for the cassette and use a double rather than a triple and go with a 36/52. That combination gives me the same top gear as we have today and a similar low gear.

We currently have 30/39/52 with a 12-27 cassette. Top is 114 inches and low is 29.3. With the 36/52 and the 12-32, top is still 114 and low is 29.7. Probably low enough, we climbed an 8% grade yesterday in the 30/27 with no problem, that is probably as steep as we will climb. For us that would eliminate the need for a triple. And the ratios are not that bad. An 11 speed might be another consideration to keep the ratios a bit closer.

Wayne

Turbotandem

I agree. A lot of teams, but not all teams, I believe would be happy with that configuration. And if not low enough, a 34-50 or 34-52 are a fine chainring set. And the SRAM 11-36 is the same as the SRAM 11-32 with I think just the 14 or 15t cog missing from the top 9 cogs, and the 36 added over the top of the 32. Should a team worry over the years that 29" or 24" are not low enough for climbing, or want to take on touring weight, a triple is not an impossible modification with one replaced stoker crank and a FD from the choices above.

waynesulak

What was your lowest cadence on the 8% climb?

twocicle

So, I stayed up late last night stripping down, cleaning and rebuilding my single with all new DA 11spd mechanical (non-Di2) stuff, then today went for a 1st ride. The components all worked great and I think the compact 50/34 rings x 11/25 cassette is a cool combination.

That said, my impression is that the gearing needs to be so precisely tuned that installing this mechanical 11spd group on a tandem would be a serious mistake. The front derailleur does not have great range in spite of a "converter" cam that supposedly alters the throw range. The rear gearing not only has the usual SIS tuning needed to click up & down cogs, but now the tuning must place the jockey wheels perfectly centered on a cog, else the chain starts to chatter. Tuning a 10spd is tedious enough, but a long cable run on a tandem would likely make the 11spd really tiresome.

If I were to consider putting any Shimano 11spd (or more in the future) on a tandem, I would be shopping for a Di2 setup where the electronic shifting places the chain exactly where it is supposed to go, and no slop or guesswork.

Just my 2 cents comparing 10 vs 11spd setups on different bikes.

---

FYI, here is the location of Shimano "Dealer manuals" (aka install guides).

DubT

i do not know, do not use a cadence feature.

I would estimate between 70 and 80. I use and app on my iPad called Gear Head and it calculates gear inches, speed etc, based on our speed of around 6-7 MPH I get that rpm.

waynesulak

That cadence seems about right for that speed gear combination. While we have climbed at that cadence but it is something we like to avoid. We like to keep our cadence around 90-95 with a few rpm leeway one way or the other so say 88-97.

Dean V

You must have some low gears to be able to hill climb at that cadence (unless you are very fast!).

Ritterview

I have had Campy 11-speed on our tandem for 3 years, and though the front shifting has been a trial, the rear (11-speed) shifting has been no problem whatsoever. The problems with the front shifting due appear to relate to the 11-speed narrowness of chain, in combination with 10-speed, Shimano spec chainrings and front derailleurs. But, I think you are anticipating problems with rear shifting, and that hasn't been the case with us.

waynesulak

Your right about the low gears. We are slow climbers. Low gear is 24/28 which at 90 cadence lets us blow by people at 6 mph! Our tandem came with a low of 30/34 which is about the same gear. The difference is our cassette is fairly closely spaced with the biggest jump 15 cog to 17 cog. Top gear is 50/12 which we spin out at about 33 mph. Middle ring is a 36. Traditional TA rings using 110 BCD, the vastly inferior standard that has been around a very long time and currently allows innovators like Lightening, DaVinci, Praxis, and Rotor to make products that fit a wide variety of ring and crank brands.

twocicle

In context, I was referring only to Shimano 11spd setup and comparing that to the 10spd we have on our tandem. Campy may be another matter.

The 11spd compact w/mechanical shifting is working perfectly on my single, both front and rear with no hitches. The precise setup required to get it that way was my concern as I have yet to have any tandem shifting perform as good as on a single.

twocicle

Depending on hub & spoke config, it may be feasible to install a 11spd cassette on a 9/10spd freehub as I have done on my single bike's Mavic freehub.

see this thread: https://www.bikeforums.net/showthread...syrium-SSL-hub

This would be a huge boon for the tandem wheel crowd, as investing in new 11spd specific hubs may not be necessary in all cases.

Belly up to the cassette bar and order some tasty shots.

DubT

My daughter has a new Cannondale Evo that is equipped with DA 11 speed. Her mechanic recently converted a set of Easton racing wheels from 10 speed to 11 speed for her. I think that he was able to order a new cassette body and install it.