Steve_sr

Hello,

This question may test your long-term memory a bit! I have a road bike with a Shimano Ultegra 6603 triple setup. The current gearing goes down to 30:30 or 1:1. I am doing some touring this summer in Europe where there may be considerable steep sections where this now 67 year old could use a bit lower gearing.

I am thinking that the best option might be to put a larger cassette on the back. I currently have a 12-30 on there which I think is the largest that Shimano intended to run. I am wondering if anyone knows if it is possible to put a larger cassette on there and if so how far I can go and still have decent shifter performance. I am thinking that a 34 might be enough.

Your thoughts?

Thanks,
Steve

Andrew R Stewart 

Many shops and basement wrenches have done similar gearing changes. My suggestion is to put on the lowest gearing you can, even at the cost of higher ratio ones.

At the rear I would suggest replacing the road spec der with a MtB one that matches the indexing cog count spec. IIRC the 9 speed Shimano MtB ders are cross compatible with 9 speed road shifters and cassettes, so a cassette with a 34T low cog can be used.

In front the 30T ring can be changed out to as little as a 24T. But the shifting starts to really degrade (assuming common/poor shifting skills), the gap to the 39T (or 42T) ring grows and cross chaining becomes more problematic. As front shifting is so very rider skill dependent some riders who exceed the spec ring range will have little problems dealing with shifting onto and off of that inner ring. But some riders (sometimes on rides I think this includes most of my riding partners...) have issues with front shifting the in spec/OEM front systems and these riders will really suffer with a huge front ring teeth count spread.

Are we to assume that the rest of the bike's design and features will handle the tour's load needs? How wide a tire can you fit? Andy

Bill Kapaun

It's 10 speed according to this chart.
I don't deal with road, so I'm not sure if 9 speed mountain RDER's work with 10 speed road shifters. I think they do???

It appears his 30T cog is already 3T over the recommended max
Does the chain sag already when in LOW:LOW?

With a 38T chain wrap capacity, it ain't going to happen "gracefully" without a "mountain" RDER.

Steve_sr

Exactly, I don't need Lance gearing at the top.

This is a 10-speed setup with a 10-speed brifter up front which would not be easy to change out. I don't remember if that is where Shimano broke road/MTB compatibility. My ancient MTB is 7-speed so don't really know if Shimano did a 10-speed MTB groupo.

According to the tour leader he thinks that the road bike would be fine with 28's. He thought that a gravel bike would be overkill.

Thanks,
Steve

icemilkcoffee 

Yes. 7sp to 10sp road and 7sp to 9sp MTB rear derailleurs have the same pull ratios. So a 9sp MTB RD would work here

dedhed

6600 will shift a 9 speed mountain RD.


​​​​​​https://www.wolftoothcomponents.com/...erailleurlinks

70sSanO

You can use a 9 speed MTB RD with your older 10 speed STI shifters. You need to keep the road FD. The main issue is current 9 speed RD’s are falling by the wayside and except for a Deore here and there, the choices are Alivio and Acera.

A 9 speed XT, or XTR, from the past would be nice with your setup.

Here is my reality. I’m running a 6500 triple with ac 28-38-48 (flat rings but I don’t mind). My RD is an XTR M910. I’m only running an 8 speed cassette, but the largest cog is a 36t. No issues indexing.

If you find an XT 750 SGS it should work fine. Even the 760/770 or 960/970 would be great. But be careful to avoid the rapid rise versions.

John

GamblerGORD53

Tour leader?? Is it a supported ride?? If so, I think just put a 28T or 26T on the front and try that.

base2 

I think your problem with a triple in the front will be the total capacity of the derailleur. As noted, you are already over the max cog size by 3 teeth.

A smaller crank set may be one solution. Another is to build a wheel around a Sturmey-Archer CS-RF3. Same ratios as a triple but all inside the rear hub. The caveat is your drive ratio is limited to 1:1 but the internal reduction of first gear lowers the realized gearing 25%. 1:0.75 is a pretty low gear.

The next question is then to cable routing. Any 3 speed mountain triple shifter ought to run it. Your road shifter won't on account of pull ratio. But it ought not be too hard to find a place to mount a shifter pod. Paul makes SRAM 31.8mm pod adaptors to mount to modern handle bars. You can also hollow out the clamp of a flat bar shifter & mount to the round part of road bar.

The CS-RF3 also comes with a cable stop meant to run full housing along the top tube to the seat stay then bare cable to the hub. As for mine, I used a pulley to facilitate routing and utilized the original front derailleur routing; Only to the pulley high on the seat tube instead of the derailleur. Then from the pulley down the seat stay.

The gearing is ridiculously wide. You sacrifice nothing and a new wheel is a lot cheaper and more efficient than a Schlumpf Drive.

But yeah. A mountain triple crank set is probably your cheapest option with a 22 or 24 tooth small ring would get you up the hills as long as you aren't in much of a hurry with that 42 tooth big ring.

Have you thought about a 12 speed bar end shifter in friction mode with a modern huge capacity derailleur? Derailleurs are up to something like 47 teeth capacity now. The derailleur won't care about the chain size or actual speeds. That's the cassettes job to worry about.

Duragrouch

Assuming 700c x 32, 30:30 gets you 27 gear inches. That's high for touring with steeps. A minimum, you want 20 gear inches, and some tourers who run 15-20% grades on loaded bikes use 15 gear inch lows.

A large wheel bike certainly has room for modern ultra-wide-range cassettes. A 40T low cog in back gets you 20.3 gear inches with your current crank. 52T cog gets you 15.6 gear inches. And of course you can go in-between.

If you want to change the crank instead, a 22T low chainring x 30 cog gives you 19.8 gear inches. A 17T low chainring gives 15.3 gear inches, I don't know if rings come as small as 17T.

With large wheels like that, you don't need a huge chainring to get the highs you need. I know they now make 110BCD 50/34 doubles (16 tooth difference) that shift great. If you can find one of those in a triple for a smaller low, that would be great. 50 x 12 cog gives you 112.5" high gear, that's plenty tall for non-racing, easily enough to power down grades, my 85" high is enough to pedal down mild grades, so you could go a good deal smaller than 50 and probably be set up great. I don't know the availability on various triple setups these days, look on amazon. If you run a JIS tapered (most common) bottom bracket, there are tons of triples available, but some are heavier than others. 130 BCD (road), limits you to a 39T as your lowest chainring, you'll probably want lower than that so I would recommend 110 BCD, unless you want even lower than 50/34 as your high and middle rings, in which case you want to go smaller than 110 BCD.

In my latest conversion, I converted to a hollowtech II style crank with external bottom bracket bearings (replacing the square taper bottom bracket), and that has been a huge plus, the bearings are more durable and, unlike a cartridge, can adjust the side preload to take up bearing slack as it wears.

Lastly, your climbing style matters a lot; If climbing 100% while standing on the pedals (in finest tour de france style), you can push a higher gear. The values I noted above assume you may run out of wheaties and will need to sit and spin your way up. I don't push nearly as hard when seated, as it can cause knee pain. Standing, straight leg, I can climb in a higher gear, in fact if standing, it is tiring to run too low a gear at a much faster cadence. When standing, I go for a gear where I am not pulling hard on the handlebars, just using my weight on the pedals, in a relaxed cadence.

delbiker1 

Isn't the rear DR a medium cage. I am pretty sure the max is larger than 30.

What I am using: a compact double, 6750, that I switched the big ring out for a 46 tooth. The rear derailleur is a 6600 short cage, I am using an 12-34 cassette with it, and have had a 36 on there. I have another bike with 7000 group with medium cage derailleur switched to 46-38, rear is a Shimano 11-40 cassette. Again, it all operates just fine. So, if the DR is actually maxed at 30 tooth, It seems if you can get a smaller big ring for your triple, you could have larger cogs at the rear. I am pretty sure you can 32, maybe 34 big cogs to work with a short cage.

Steve_sr

Thanks for the info and advice. I guess that I should have mentioned that this will be a supported tour so I won't be carrying full gear, just what is needed for the day.

Yes, the Wheaties don't work like they used to!

Andrew R Stewart 

The issue of low enough gearing on any tour, loaded and self contained or fully supported is that riding up the hills is never an issue of strength but of stamina or motivation. Even when totally wiped out from a hard day most can still pedal hard for at least a stroke or three. But to keep that up for a few miles (longest hills I have gone up have been 4+ miles long and took over 4 hours and lunch stops to crest) is not what many feel makes for a great ride. Very low gearing lets one climb and stay within their anerobic threshold, very important if there's still 40 more miles to go and many more days ahead.

Now knowing that this tour will be a fully supported one my concerns on the bike being not the best choice is lessened somewhat.

Have you visited the Touring sub forum here yet? There's a lot of good help there too. Andy

Steve_sr

Interesting thought. I have been unable to find the specs on the 6600-GS long cage RD. I just spent some time on the Woolf Tooth web site and I see some interesting links for extending RD range. However, I think that these replace existing links in the newer RDs and the 6600 mounts directly to the hanger on the frame without a link.

delbiker1 

I believe the Wolf Tooth Road Link will work with your derailleur. It just attaches to the present dr mount, then the dr mounts to it. All it really does is keep the chain further from the cassette to give more room for larger cogs. I live in flat land, I need no more than a 46 front, ever. The 34 rear cog I never use here locally, but when I travel to areas where some climbing is necessary, it is there. Now, my Soma Smoothie with the 46-38 and 11-40 is going to be my traveling bike. When I ride locally, unless it is very windy, I can ride that as a 1X in the big ring. Going into a strong wind, it pretty much becomes a 1X in the small ring. I am really going back to simplifying my 2 wheel world. "Multi-Use" bikes are what works best for me at this point.
I think 6600 rear dr came in only short and medium cage. That may be true for the road groups that came after 6600. And I certainly could be wrong about that. I googled and found info that states both the short and medium cage DR have the same capacity listed, but lots of info on that being stretched. What I really know is what I tried, and works, on my bikes. There are almost always going to be different approaches to get the gearing that is wanted, at least real close to it. Some of what I have done was simply a matter of wanting to try, but not wanting spend dollars to do that. If it does not work well, it's a learning experience, or not.

kcjc

https://si.shimano.com/en/pdfs/si/5V...0C-001-ENG.pdf

70sSanO

No one can tell you what gear ratio you need. You probably should find out the steepest grades and length and find similar climbs to test your current gearing out.

If you are close with the 30:30, then maybe a 30:34 will be fine, or a 28:30. Over the last 10 years I have seen my gearing in a steady regression, I’m 72.

The reality of available chainrings is a Shimano 28t 74mm 5 bolt rings are getting tough to find, and 10 speed Shimano versions may never have existed. There are other alternatives. Can’t speak of ring width spacing on non-spacer inner cranks, but older SG mtb rings may not line up the best on a fixed mount.

Shimano 30t 74bcd rings are pretty easy to find.

I might probably opt for a 12-36 with a 30t ring so you get a 30:28, 30:32 and an Oh $&*# 30:36. If that is not enough, there are some less desirable options.

SRAM has a 12-13-15…28-32-36 10 speed cassette.

John

reburns

I have an early 2000’s road bike that started out 3x9 speed and still has 30/42/52 chainrings, 6500 RD and 6503 FD. It was converted to 3x10 after a collision that may have damaged an original 9 speed brifter which was no longer available, so brifters are now 6700. I now use an11-36 cassette with wolf tooth road link and it all works great. My chain is long enough to avoid damage if somehow it was inadvertently shifted to the big/big combination. It may get slack in small/small, but I never get close to that selection.

ShannonM

If your middle ring is a 39, swap your 53 outer for a 46, and your 30 for a 26, or even a 24. (The 26 puts you back within the 38t chainwrap of your rear derailleur, but the 24T is only +2, and you're at +3 right now.)

This gives you a range from ~104" down to about 21.5", and your existing derailleurs should handle it just fine. The road triple front should play nice with the 7T difference between the middle and big rings, and your rear derailleur already works with the 30T big cog. Plus, 130 and 74 BCD chainrings are cheap... a 46Tx130 and a 24Tx74 should come out under 75 bucks if you shop around. Way cheaper than a new 10 speed cassette and a new rear derailleur.

Take a couple of links out of the chain, lower your front derailleur a bit, adjust the front shift cable, and Bob should be yer Uncle.

--Shannon

Steve_sr

I tried calling Wolf Tooth today and no one answered so I sent them an email. We'll see if they answer that.

I definitely have the long (medium?) cage version of the RD-6600. The linked spec shows a total capacity of 37 for the GS and 29 for the short (SS) versions. Unfortunately Shimano doesn't spec components "limits" but only specific combinations that they want to sell and are proven to work together. As you found out (and I am looking for) an "outside Shimano" combination that still works sufficiently well.

BTW, how does one measure/calculate total "capacity" that is required for a given chainring(s) and cassette? What happen if you stretch the capacity over this amount? Does the chain get loose and sag (assuming that it doesn't break anything in "big-big"?

Steve_sr

I managed to pull off a van supported TransAm in 2022 with the current 30:30. I only had to walk once... on Sheep Grade Rd.

This year I am doing Mallorca in May and Eastern Block and Austria in August-September. I would like to have a little more dry powder.

I am headed that direction as well. I seem to have lost a LOT in just the past year and I just turned 67.

I think that a 12-36 would probably work, at least at my current age! LOL. Is SRAM compatible with Shimano? Did/does Shimano make a comparable cassette?

Thanks,
Steve

Steve_sr

So which RD do you currently have with the 11-36 cassette? I don't think that Shimano ever made a long cage (triple) RD in the 6700 series.

Kontact 

I used to work for a shop that also had a Pyrenees bike tour once a year. We commonly swapped the customers' chain, cassette and rear derailleur for the trip, than swapped them back out when the travelers got back to Wisconsin. The whole swap took 20 minutes and was relatively cheap to do on either SRAM or Shimano bikes. Same crank, FD, shifters, cables, wheels, etc.

Chainring changes have enough issues that you might end up swapping the RD anyway. Just do the RD and cassette.

Steve_sr , I don't know if has been explained clearly, but that Deore derailleur is just called "9 speed" because that was how it was packaged as a group set. But the derailleur is agnostic and you use it with a 10 speed cassette if you have 10 speed shifters, or 8 with 8, etc.

ShannonM

Capacity (AKA chainwrap) = (big_ring - small_ring) + (big_cog - small_cog)

As to what happens if you exceed it, and, as you said, assuming that you've got enough chain for big/big to not lock up, the worst that will happen if you go the other way (small/small) is that the chain will drag on the back end of the front derailleur cage, and make a bunch of noise. Since that's not really a gear that you'd ever ride in, even by accident, it's not too much of an issue.

I'll use, as an example, my '85 League Fuji. I'm running a Deore MT60 crankset, 45/42/30 (half-step + granny,) with a 14-26 6-speed freewheel. Derailleurs are a Suntour AR double up front (triple front derailleurs mostly can't cope with the 3T difference in chainrings,) with a 1980 Suntour Superbe short cage out back. (Hey, if you've got a new-in-the-box 1980 Suntour Superbe, you use it, right?) The Superbe has a capacity of 20 teeth, and a max cog of 23. I'm running it at (26-14) + (45-30) = 12 + 15 = 27 teeth, so I'm way beyond spec. In practice, I only ever use the three lower cogs on the the freewheel when I'm in the granny, the 26, 23, and 20. The 18, 16, and 14 cogs on the 30 are duplicates of other gears on the middle and big rings, so I never use them. It starts to get noisy in the 16/30.

Derailleur specs are really, really conservative, and, if you're going to violate them, a smaller big ring covers up a lot of sins.

--Shannon

Kontact 

This is exactly how everyone used short cage XT derailleurs in the '90s.