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Out of the box, gravel bike gears are too high. Here's how to sort them out

Want lower gears on your gravel bike? We do, so we set about combining some parts that aren’t supposed to work together to get a massive gear range. Ssshh, don’t tell Shimano.

Gravel bikes are over-geared.

Typical gravel gearing

Out of the box, your typical gravel bike has a 50/34 chainset and an 11-32 cassette, giving a range of gears that’s fine on roads unless you’re riding somewhere very hilly, but with limitations you very quickly bang up against when you venture off road.

That bottom gear is far too high. When I head out of Cambridgeshire to the gentle slopes of Suffolk I find myself wanting something lower for longer climbs. When he tested Trek’s new Checkpoint David Arthur — who is much, much fitter than me — found he had to get off and walk when riding the Cotswolds. "Compact chainsets have no place on gravel bikes," he said in a road.cc office discussion of the issue.

In gear inches that typical 50/34 & 11-32 set up has a low of 29in and a high of 123in — a 428% difference between smallest and largest.

Not only is 29in too high, but so is 123in. You’re never going to use that top gear off-road and you’re not going to get much use from it on the road either. (I could digress into a rant here about component makers supplying almost nothing but pro-class top gears on bikes that will never see a sprint for the line, but that's a topic for another time.)

Let’s try and cook up a better gear selection.

Sprockets

gravel gearing 4.JPG

The arithmetic of gearing makes a change of sprockets the most effective way to get lower gears, and in the last few years Shimano and others have made available 11-speed cassettes with ranges of 11-36, 11-40, 11-42 and even 11-46, all with the same sprocket spacing as our gravel bike’s 11-32.

But there’s a problem: no Shimano road derailleur is rated to work with a sprocket larger than 34-tooth. How about a mountain bike derailleur? Nope. For some reason known only to Shimano, their 11-speed road and mountain bike shifting systems aren’t compatible. Back in the nine-speed days you could use a Deore XT rear derailleur on a road bike if you wanted to, but that’s not the case for 11-speed. What to do?

Well, Shimano’s assessments of derailleur capacity have always been conservative. When Shimano say something won’t work, that often means it won’t work to the high standards Shimano sets, not that it won’t work at all.

And this is what we find with Shimano’s latest GS line of 11-speed 'Shadow' road bike rear derailleurs. The £58 Ultegra R8000 medium cage derailleur (RD-R8000-GS for fans of part numbers) is not supposed to be able to shift to a sprocket bigger than 34-tooth, but YouTube is full of backroom tinkerers demonstrating that it works just fine with an 11-speed 11-40 cassette.

gravel gearing 5.JPG

The 105 GS rear derailleur looks geometrically identical to the Ultegra, but is typically £20-£30 cheaper. Could this be a cheap way of getting really low gears on a gravel bike?

To find out, I bought a 105 RD-7000-GS rear derailleur (£36.95), an SLX CS-M7000 11-40 cassette (£40.77) and an 11-speed Shimano chain (£19.01). I thought about pushing my luck and going for 11-42, but I wussed out. Maybe another time.

The cassette is a big beast of a thing. I don’t think I’ll ever quite get used to just how huge a 40-tooth sprocket is, never mind the 50-tooth and bigger sprockets now available for mountain bikes. Rotor’s 13-speed system includes a 52-tooth sprocket. When Ah were a lad, that were a chainring!

The 11-40 cassette fits straight on the hub of my Prime RR-28 wheels in place of the 11-32, and the 105 R7000 GS rear derailleur substitutes perfectly for the 105 5800 GS unit. To give the derailleur the best chance of handling the big sprocket I dial the B-tension ‘angle of dangle’ screw all the way in, pulling the body of the derailleur as far back as it will go. I tweak limit screws and cable tension and run carefully up and down the gears.

Success! It shifts just fine to that huge sprocket, clicking into place as if it were designed to.

I’m still running the original chain, so I try shifting the front mech into the big ring. Bad idea. It’s immediately obvious that things are going to go seriously wrong if I try to use the big/big combination.

I ditch the original chain and fit the new one I’ve bought. At this stage I don’t have the chainset I want to use, but I want to ride this weekend. The existing chain would probably work fine with the 46/30 chainset I’m waiting for.

Out on the road and the trail, the difference is soon obvious. I keep glancing down, thinking I must be getting close to the lowest gear, and finding I’m actually in the middle of the cassette.

This isn’t very surprising. The 34/25 combination on the old set-up, 37 gear inches, was two gears from the lowest. In the new set-up’s 34/24 (38.3 inches) I still have four lower gears.

My proving ride takes riding buddy Al and me down a narrow, wet bridleway into the village of Linton, home of the excellent Linton Kitchen cafe. We’re in the middle of a drought, but the leaky water tower at the top of the hill means there’s always a stream here to flick mud up at you.

Fuelled by coffee and carrot cake, we tackle the bridleway in reverse. My state of fitness could be accurately described as woeful, but nevertheless, it’s a doddle. The average gradient of the top section is about 10 percent, which by Cambridgeshire standards makes this a Proper Hill™, and climbs on trails never have perfectly even gradients. I pootle up it easily. Al zooms on ahead. Not having a 34/40 low gear he doesn’t have any choice, I tell myself. It’s nothing to do with him being a lot fitter than me. Ahem.

For fans of gear charts, this is where we started:

  11 12 13 14 16 18 20 22 25 28 32
50 122.7 112.5 103.8 96.4 84.4 75.0 67.5 61.4 54.0 48.2 42.2
34 83.5 76.5 70.6 65.6 57.4 51.0 45.9 41.7 36.7 32.8 28.7

 

And this is where we are now:

  11 13 15 17 19 21 24 27 31 35 40
50 122.7 103.8 90.0 79.4 71.1 64.3 56.3 50.0 43.5 38.6 33.8
34 83.5 70.6 61.2 54.0 48.3 43.7 38.3 34.0 29.6 26.2 23.0

 

In short, we’ve stretched the range from 428% to 538% with no downside except for a bit of extra weight. I think the gaps between gears are still reasonable; more on that later.

To go even lower (and wider) we’re going to need a change of chainset.

Chainset

One thing I wanted to avoid in this project was trying to persuade road and mountain bike components to work together. There was a time when you could cross the streams easily, but Shimano’s road and off-road derailleurs now have different geometries, so you can’t use mountain bike mechs with road shifters without some sort of cable pull converter. That’s a level of bodging I wanted to avoid.

gravel gearing 6.JPG

That means the chainset can’t be too small or a road front mech won’t work well with it because the curves of the cage won’t follow the shape of the chainring. I therefore settled on one of FSA’s Adventure chainsets in a 46/30 'sub-compact' configuration. That’s enough of a difference to be worth the hassle, but not so much that the shifting will be balky.

FSA makes several 46/30 cranksets, from the high-zoot K-Force and SL-K Modular units with carbon fibre arms to the inexpensive Tempo CK Adventure cranks that fit old-school square taper bottom brackets. In the middle, at a sensible price and weight, there’s the new Energy Modular BB386 Evo crankset (£200), with hollow forged aluminium arms, so I went for one of those.

gravel gearing 3

Fitting was straighforward, with just one caveat: the position of its mount stopped the front derailleur going quite as low as I’d have liked. The front derailleur cage ended up a couple of millimetres higher than Shimano recommends.

That’s another reason not to use a mountain bike chainset. If you have a braze-on front derailleur it’s unlikely you’d be able to get it low enough for the 38-tooth outer of a typical mountain bike double — and of course you probably want a higher top gear than the 38 ring would provide.

The gear range

With the FSA 46/30 chainset, the resulting gear range is massive. Here’s what it looks like:

  11 13 15 17 19 21 24 27 31 35 40
46 112.9 95.5 82.8 73.1 65.4 59.1 51.8 46.0 40.1 35.5 31.1
30 73.6 62.3 54.0 47.6 42.6 38.6 33.8 30.0 26.1 23.1 20.3

 

That’s a 558% range, much bigger than the 428% we started with and most of the extension is at the bottom of the range where it’s most needed. But we’ve also preserved a decent high gear for those zoomy road descents.

Only mountain bikes have lower gears. While single-chainring gearing has all but taken over on mountain bikes, some double-chainring bikes are still available, with gearing down to a positively wall-climbing 22/42 (around 15 inches, depending on wheel and tyre size).

Those systems sacrifice the high end though. With a 36/11 or 38/11 top gear (around 90 inches) you’re going to be doing quite a bit of coasting on descents.

Riding

Out back, the 105 rear derailleur clicks effortlessly and without fuss from one sprocket to another, even when it gets to the final 35 and 40-toothers that it's not supposed to be able to handle. Up front, the old 5800 front mech flips easily between the 46 and 30 chainrings.

This set-up is noticeably gappier than the one it replaced. There are a couple of 15 percent jumps between gears, and the gap between the two highest, provided by the 11 and 13 sprockets, is a whopping 18 percent. I can live with that, but if you're a finely-tuned pedalling machine who struggles to change cadence more than a few percent, you're going to find it a bit jarring.

The big advantage of a gear set-up like this is that it reduces the need to hit the redline every time you go uphill. Back when I was doing a lot of mountain biking, I was always the guy pootling along at the back while everyone raced up the first couple of hills. And I was the one with plenty in the tank at the end of the ride, sitting on the front towing everyone for the last 10 miles home.

Tweaks and alternatives

If Shimano's 11-40 cassette is just too gappy for you, SRAM makes an 11-36 11-speed cassette (£63.05) that shrinks the biggest gap by dropping a 12 between the 11 and 13. With a sub-compact chainset like the FSA that still yields some usefully low gears. SRAM says the 11-36 is only compatible with single-chainring gear systems, but that's almost certainly a matter of marketing rather than engineering.

If you wanted to go electronic, you could assemble a Di2 version of this transmission without breaking any of Shimano's rules. The XTR and Deore XT electronic rear derailleurs work with Ultegra and Dura-Ace Di2 drop-bar shifters. The Di2 rear derailleurs are rated for a 42-tooth sprocket in a 2 x 11 system, so you could go slightly lower than I have. I'd love to hear from anyone who's tried this.

WolfTooth RoadLink

If you wanted to save money, you could use a £22.95 Wolf Tooth Roadlink to extend the capacity of your existing rear derailleur. According to the manufacturer, the Roadlink will extend any non-Shadow GS rear derailleur to work with an 11-40 cassette.

That'll work if you're still running 10-speed too. SunRace makes a couple of 11-40 10-speed cassettes, the £30.59 MS3 and lighter MX3 (£40).

Conclusion

I think the system I’ve put together provides the best wide-range gravel bike gearing currently available, at a sensible price. It's very handy that it can be put together in two stages and the most effective one — changing the sprockets — is the cheaper.

There are plenty of arguments for alternatives, though. People fitter than me like the simplicity of 1 X 11 systems and are prepared to sacrifice a bit of range to get an easy life, and more power to them.

It's a pity Shimano doesn't make it easier to put together a wide-range system like this. They could offer SGS versions of the Ultegra and 105 Shadow rear derailleurs, for example, with the capability to handle 11-40, 11-42 or even 11-46 cassettes. And they need to offer chainsets with smaller rings and front derailleurs that work with them. Maybe next year, eh?

Acknowledged by the Telegraph as a leading cycling journalist, John Stevenson has been writing about bikes and cycling for over 30 years since discovering that people were mug enough to pay him for it rather than expecting him to do an honest day's work.

He was heavily involved in the mountain bike boom of the late 1980s as a racer, team manager and race promoter, and that led to writing for Mountain Biking UK magazine shortly after its inception. He got the gig by phoning up the editor and telling him the magazine was rubbish and he could do better. Rather than telling him to get lost, MBUK editor Tym Manley called John’s bluff and the rest is history.

Since then he has worked on MTB Pro magazine and was editor of Maximum Mountain Bike and Australian Mountain Bike magazines, before switching to the web in 2000 to work for CyclingNews.com. Along with road.cc editor Tony Farelly, John was on the launch team for BikeRadar.com and subsequently became editor in chief of Future Publishing’s group of cycling magazines and websites, including Cycling Plus, MBUK, What Mountain Bike and Procycling.

John has also written for Cyclist magazine, edited the BikeMagic website and was founding editor of TotalWomensCycling.com before handing over to someone far more representative of the site's main audience.

He joined road.cc in 2013 and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.

106 comments

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pratn0 [1 post] 1 year ago
4 likes

I'm currently running a DI2 XT derailleur on an sram 11 - 42 cassette(left over from the old setup)  on a 1x 42 front chain ring (soon to be absolute black oval).  no chain catcher the clutch seems enough as not had any chain drops yet.

I'm running the R785 STI's and have to sprinter blips soldered into the cabling of the R785s that sit under the top for stealth shifting changes while climbing . i've configured them to change down on the left buttons and up on the right.

I've kept the MT800 display on the bars so i have connectivity from the system though Bluetooth to my head unit and phone.

Had no issues with the shifting and the system has been solid.  love it and now looking how i can get Di2 on the road bike on the cheap.

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cjhfield [1 post] 1 year ago
1 like
alanmc wrote:

Another option for sub-compact chainrings on a Shimano chainset :

https://absoluteblack.cc/oval-road-chainrings-30-46-and-32-48-for-110-4bcd/

 

 

I run this on my Trek Domane for Audax rides. I think the jury is still out on whether the oval shape is an advantage but it does allow 46/30 on a standard Shimano 4 arm crank. The front derailleur sits rather higher than ideal but it changes fine. I run 11/36  at the back. Excellent low gear for 200 metre climbs at the end of a 600km Audax.

 

Chirs

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deepakvrao [1 post] 1 year ago
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My wife and I live in India, but frequently travel to the Alps, Jura and the Pyrenees. We usually carry luggage on our bikes. These are regular titanium road bikes with regular road gearing. We also do some rides off road, and that with luggage means we 'need' a lower gearing.

When we travel, I swap out our regular cassettes, and put on a 11-36 cassette on mine, and a 11-40 on my wife's. 

The setup is Rival shifters, SRAM Via GT [an odd SRAM RD which can take a 36 cog cassette], and on my wifes bike, I put on a Roadlink for the 40 cassette.

Was wondering if I can put on a 11-46 with the same set up. Any ideas?

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CXR94Di2 [2761 posts] 8 months ago
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CXR94Di2 wrote:
Shades wrote:

My hybrid/tourer MTB triple chainset (Deore I think) needed replacing.  I wanted to simplify things and the mechanic came up with a Shimano SLX set-up; 38/28 with 11-42 cassette.  Good low gears for hills and enough to cruise along the flat.  Not a set-up that I've seen on a bike in an LBS.

I was running a 40/28 XT crankset but found I had too high a cadence on the flats or slight decline to keep up with guys on compact crankset, so I upgraded the outer ring to 44t which was much better, almost perfect setup for me. But I then wanted even more speed and reduced cadence, so I upgraded my setup to triple with 48t outer chainring. (see above)

I now have a bike (Kinesis Tripster V2) which I can use for fast flat riding 22+mph and with even lower gearing than my MTB double crankset for alpine climbs, the chain line is much improved with less chain deflection, being Di2 I can program the shift sequence to chain alignment optimal.

My range in gear inches. is 17" to 115"

Ive gone onto a triple now 48/36/26 with Di2 XTR derailleur, for even better climbing and higher top speed

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bdr [2 posts] 8 months ago
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I tried the very same setup on my Kinesis Tripster AT and was not able to get satisfactory shifting. Setup: SpaCycles triple TD-2 crank with 46-30T chainrings, Ultegra RX-800 RD, 11-40T SLX cassette. Shifting does work fine with a Wolftooth Roadlink DM, although there's no chain tension in the small-small combination. Chain length was determined by the big-big measuring method. I cannot remove any more links.

Running an 11-40T casette with the stock R7000, R8000, RX-800 derailleur will be highly dependant on your particular derailleur hanger. 

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Dominic Schulz [2 posts] 7 months ago
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I use that mentioned SRAM PG 1170 11-36 cassette on my ultegra 8000 equipped gravel bike (with a compact) and it works absolutely fine. Thats plenty of a low-down gear already, however i just never ever used the top gear, so a  less-than-compact front chainset would probably be a good idea as soon as i start touring with a big of extra wheight in the bike. i wouldnt lile bigger jumps between gears on the cassette btw. Keeping an eye on that FSA crankset. there is also the option of using absolute black 30/46 chainrings if you already use a recent shimano road crank. they have a special design to fit the small ring to the 110mm cranks. 

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littlemig [13 posts] 7 months ago
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Dominic Schulz wrote:

I use that mentioned SRAM PG 1170 11-36 cassette on my ultegra 8000 equipped gravel bike (with a compact) and it works absolutely fine. Thats plenty of a low-down gear already, however i just never ever used the top gear, so a  less-than-compact front chainset would probably be a good idea as soon as i start touring with a big of extra wheight in the bike. i wouldnt lile bigger jumps between gears on the cassette btw. Keeping an eye on that FSA crankset. there is also the option of using absolute black 30/46 chainrings if you already use a recent shimano road crank. they have a special design to fit the small ring to the 110mm cranks. 

I have a similar setup with a compact but r7000 mechs and 5800 shifters. All good. I found lowest gear of 34-34 was not quite low enough for a few sections of where I ride off road. The 11-36 helps. I didn't use road link. Just had to be careful with chain length and then adjust the b screw. All seems to function very well.

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morlbo [2 posts] 7 months ago
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Ok. first of all sorry for my english language. and sorry for late commenting.

Now, first problem I want to bring is not the rear mech itself SM105GS and chain climb over a 40t end position, but the overall capacity of the drivetrain, which is supposed to be 37t.

Now a 46/30 can be surely called a low gearing and 20.8 Gear inches is a good MTB wall climbing gear indeed, if we want to put a 19 Gear inches limit from the triple era: granny 24t front vs 36t last position cassette, what I call super-low.

558% too is a great achievement but not in a 45t drivetrain. I'm Asking me how you can manage it, with a 37t RD, and a Wolftooth even if want to expect a +5t from it.

It seems to me your chain is quite short, and a MTB RD must come in.

A more "standard" 36/20 11-36 has 536% ratio in "just" a 39t drivetrain easyer RD climb and more manageable +2t over the RD capacity.

Personally I can't live without 11-12-13-14-15 in flat lands riding slick wheeled. I my opininion a compromise can be found in a bigger jump in the FD, 17t or 18t even in low gearing. Most can feel it uncomfortable, when swapping chain rings and have to adjust +-6 gears to compensate.
But in this way I can keep my precious narrow speeds, and get a respectable 506% to 509% respectively 20.0-101 38t and 20.8-106 39t managed by a 39t road RD capacity, instead triyng to build a MTB from gravel road bike.

http://goo.gl/FwYRhL

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andyspaceman [263 posts] 7 months ago
0 likes

Fabulous article.

To throw my twopenn'oth in:

- Not quite as compact as FSAs 46-30 chainsets, but absolutely brilliant are Praxis Works 48-32 offerings. Fitted a 48-32 Zayante to my gravel bike a couple of weeks ago, and am blown away by how stiff both the cranks (power transmission) and the rings (shifting) are. The 50-34 Shimano Sora unit they replaced was 'fine' and cost a lot less, but it's like chalk and cheese.

- I think double chainring is still where it's at for any gravel bike that might be pressed to bikepacking/touring/other-load-carrying duties. I'm a big fan of the single chainring on my mountain bike, but when faced with a draggy off-road climb whilst carrying kit, I want low gears AND small-ish gaps between them. Only a double (or even a triple!) with a dedicated granny ring is going to offer that, assuming that a sensible high hear is also a requirement.

 

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reippuert [123 posts] 7 months ago
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50/34 - 13/40 gives you a decent range for gravel and bikepacking.

When i build my current gravelbike only subcompact options for non taper square cranks with a road q factor was the in Europe unobtainable Sugino OX2-901D

Middleburn had the  RO2 Road X Incy but went out of business as i assembled the bike and still tried to source ideal parts. White industries was still vaporware - So i setteled with a Chorus 50/34 from my stash. 46/30 - 12/36 would have been my prefered choise though.

 

 

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x7zise [2 posts] 7 months ago
0 likes

Great article, thank you, very inspiring, especially for my arhtrosis knee!

Here's what I did: I installed on my Ridley X-Trail Alloy 2018 a  FSA Energy Modular BB386 Evo crankset 46/30, a SRAM PG 1170 11-36 cassette linked with a Wolf Tooth Roadlink to the pre-installed Shimano 105 RD-5800-GS medium cage rear derailleur. That was quite exciting since I had not done interventions of such a scale on my bikes before (thanks to youtube). Beside minor problems (shifting vom13 to 12 to 11 teeth is a bit on the slow side) it works. [Edit: I removed the Roadlink and now the system works just fine.] The difference between the single cogs is at some points quite big (I espescially do not like the 19 to 22 jump) but I suppose that is the trade off in such a set up.

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Bendurance [27 posts] 7 months ago
1 like

I’ve been running SRAM Force 1 with a Garbaruk 10-50 cassette on my gravel/monster-cross bike for almost a year now. No need for MTB RDs, shifting has been perfect with Force 1 RD and the replacement cage that comes with the cassette - just as smooth as Ultegra on my road bike.

I use a 38t chainring for day-to-day use on road and off-road (which gives me a more than sufficient top speed of 50kmh), and switch down to a 34t chainring for loaded bikepacking (SRMR last year and Italy Divide at the end of the month). 

Even on a 200km road ride the gaps rarely bother me - the bottom of the cassette has close spacing, the middle is ok as long as you have a reasonable cadence range, and the large gaps at the top are not noticeable when going that slow. Others may hate it. 

I will definitely run 1x for TCR this year. Either the above setup or possibly 38x 10-42 if training goes well. In the longer term 12 or 13 speed 10-50 cassette is where its at for me and covers all of my riding.

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Echo [18 posts] 7 months ago
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Nice links to online advertisers websites, that will keep you guys going for a while.

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gary p [21 posts] 7 months ago
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Soo...inquiring minds want to know if the rear derailleur actually had enough wrap to crosschain big/big (46/40) once the longer chain was on.  That's always the larger concern than rear cog clearance.  

 

As for the issue with the front derailleur not having enough downward adjustability on a hanger envisioned for nothing smaller than a 50/34, there is a way to bring the chainring "up" and still have the 46/30 gearing you want: ovalized chainrings.  ROTOR's new Aldhu or Vegast can be paired with a nice Direct Mount 46/30 Q-Ring.  

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gary p [21 posts] 7 months ago
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Soo...inquiring minds want to know if the rear derailleur actually had enough wrap to crosschain big/big (46/40) once the longer chain was on.  That's always the larger concern than rear cog clearance.  

 

As for the issue with the front derailleur not having enough downward adjustability on a hanger envisioned for nothing smaller than a 50/34, there is a way to bring the chainring "up" and still have the 46/30 gearing you want: ovalized chainrings.  ROTOR's new Aldhu or Vegast can be paired with a nice Direct Mount 46/30 Q-Ring.  

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TimB34 [18 posts] 7 months ago
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Been meaning to mention this for a while.. 

Although the article says "The 11-40 cassette fits straight on the hub of my Prime RR-28 wheels in place of the 11-32", shimano 11-speed mtb cassettes are actually 1.8mm smaller than shimano 11-speed road cassettes. A lot of freehubs are short enough that you can screw the lockring tight enough and never notice, but the new mtb cassette will be nearly 2mm too far inboard.

I followed the same path from 11-32 to 11-40, but shifting was a bit noisy. I eventually worked out that a spacer was needed and added one. The cassette didn't seem any tighter on the freehub, but shifting noticeably improved.

Avatar
CXR94Di2 [2761 posts] 7 months ago
1 like
TimB34 wrote:

Been meaning to mention this for a while.. 

Although the article says "The 11-40 cassette fits straight on the hub of my Prime RR-28 wheels in place of the 11-32", shimano 11-speed mtb cassettes are actually 1.8mm smaller than shimano 11-speed road cassettes. A lot of freehubs are short enough that you can screw the lockring tight enough and never notice, but the new mtb cassette will be nearly 2mm too far inboard.

I followed the same path from 11-32 to 11-40, but shifting was a bit noisy. I eventually worked out that a spacer was needed and added one. The cassette didn't seem any tighter on the freehub, but shifting noticeably improved.

 

The large sprocket MTB cassettes come with the spacer in the box to fit onto 11 speed hubs

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Tones0000 [16 posts] 7 months ago
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Thinking about the Di2 route but coming from the other direction - rather than trying to squeeze a road rear derailleur around a MTB cassette: Does anyone have thoughts or experience running 46/30 chainrings on an Xt di2 front derailleur? 

A couple of possible issues:
Is the 16T jump too large for the MTB derailleur?
Is there a problem with the BB length (68 vs 73mm)?

Other issues?

Thanks

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kiwi_gravel [3 posts] 7 months ago
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If anyone is searching for slightly weird combination of kit ..... I have been running RX800 with 11-42 Xt cassette (Ultegra shifter) on my Exploro  for past month or so. Loving the setup but having a bigger range of the SRAM XX1 10-42 would be ideal for singletrack playing.

So I rigged up a SRAM XX1 cassette onto XD freehub 650b wheels, adjusted the B tension screw (had to fully screw it in), and I now have 10-42 with 42 tooth chainring up front.  

FYI, I run SRAM XX1 mtb cranks with Wolftooth 42tooth narrow/wide chainring.

 

 

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kiwi_gravel [3 posts] 7 months ago
0 likes

*duplicate

 

 

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Nanolight006 [2 posts] 6 months ago
3 likes

Another option which is cheap and works extremely well is to use an extender for the derailleur hanger. This lowers the derailleur by about 22mm to accommodate a bigger cassette. 

I'm nearly 60 and live in Sheffield, riding in the Peak District with some beautiful but cruel climbs.

I decided to extend the gearing range on my Planet X Nanolight using the extender bought for £2.89 on eBay coupled with a 33 tooth ring from TA Specialities also from eBay.

I now run a 52-33 chainset with an 11-34 cassette with the original 108 link chain. Deraileur is 10 speed Dura ace with short cage.Shifting is still superb front and rear and I can use all gears from 52-34 to 33-11 reliably.  I think it could even be pushed to 11-36 !

The only tweaks required were simple : -  adjust b-screw to suit, and lift front derailleur about 5mm to clear slightly higher chain line as it just fouled underside of top of cage.

So all easily available parts and hardly any work at all required. Just goes to show how very conservative Shimano specs rreall are !

 

Hope this is useful to somebody.

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Tones0000 [16 posts] 6 months ago
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I assume everyone has now seen the Shimano GRX series with 48/31 and 46/30 cranksets. The big question will be whether we can bodge an 11-40 or hopefully an 11-42 cassette onto the GRX long cage rear derailleurs which are officially rated for a maximum sprocket of 34T (36T on the 10 speed) and 47T capacity (like everyone has done on the recent road derailleurs).

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CXR94Di2 [2761 posts] 6 months ago
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Tones0000 wrote:

I assume everyone has now seen the Shimano GRX series with 48/31 and 46/30 cranksets. The big question will be whether we can bodge an 11-40 or hopefully an 11-42 cassette onto the GRX long cage rear derailleurs which are officially rated for a maximum sprocket of 34T (36T on the 10 speed) and 47T capacity (like everyone has done on the recent road derailleurs).

 

Just use XT/XTR derailleurs and the new GRX crankset job donewink

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CXR94Di2 [2761 posts] 6 months ago
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Tones0000 wrote:

Thinking about the Di2 route but coming from the other direction - rather than trying to squeeze a road rear derailleur around a MTB cassette: Does anyone have thoughts or experience running 46/30 chainrings on an Xt di2 front derailleur? 

A couple of possible issues:
Is the 16T jump too large for the MTB derailleur?
Is there a problem with the BB length (68 vs 73mm)?

Other issues?

Thanks

 

Yes, I built a full Di2 bike with initally a 40/28 chainset, I upped it to 44/28.  This was the maximum difference the XT Di2 front derailleur could manage.  I would expect 46/30 would fit.

I now run an XTR Di2 front with 48/36/26, work seemlessly.  Shimano say maximum chainring is 42t-haha

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Tones0000 [16 posts] 6 months ago
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CXR94Di2 wrote:

Just use XT/XTR derailleurs and the new GRX crankset job donewink

 

Do you use synchro shift on your install? I did some calculations and it looked like you need to be careful when running cranksets with 16 (or 17) teeth when the MTB etube software assumes you are using 10 tooth differences. It appeared that users would be limited to only a few FD shift points that weren’t all that optimal to ensure that the di2 system didn’t shift “down” into higher gear or shift “up” into a lower gear.

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CXR94Di2 [2761 posts] 6 months ago
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Tones0000 wrote:
CXR94Di2 wrote:

Just use XT/XTR derailleurs and the new GRX crankset job donewink

 

Do you use synchro shift on your install? I did some calculations and it looked like you need to be careful when running cranksets with 16 (or 17) teeth when the MTB etube software assumes you are using 10 tooth differences. It appeared that users would be limited to only a few FD shift points that weren’t all that optimal to ensure that the di2 system didn’t shift “down” into higher gear or shift “up” into a lower gear.

 

Yes I use Synchro 

On twin chainrings I use it to stop the extremes of cross chaining and on my triple setup to keep the chain straight as possible.  I understand the shift points can be misplaced especially when using non standard gearing.  You can with a little experiment tweak the shift points to match your own preferred style of riding

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maviczap [392 posts] 6 months ago
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gonedownhill wrote:

Slightly off topic, but has anyone ever converted a ss Shimano derailleur to a GS by swapping the cage plates? You can buy 6800 plates from sjs cycles, lot cheaper than a new derailleur.

Bit late in seeing this, but the answer is yes, although I converted a Dura Ace 9070 Di2 to a long cage using 6800 cage plates. Think you can only do this with Ultegra and Dura Ace mechs, either Di2 or mechanical.

105 is different. But then just buy 105gs cage plates. 

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maviczap [392 posts] 6 months ago
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John Stevenson wrote:
maviczap wrote:

Praxis works do round chainrings 46/32 110bcd so works with Shimano compact chainsets

The Praxis 32-tooth inner ring only works with Praxis cranks that have the ends of the spider milled to make room for the chain.

https://road.cc/content/review/219120-praxis-works-alba-m30-4832-chainset

Not so John, they make a specific set of chain rings that fit Shimano 5 arm cranksets or SRAM with the 5th bolt hidden behind the crank arm.

The 32 inner mounts to the outer using special chainring bolts

From the back of the packet I have and fitted to a 6700 chainset

 

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JeremyBart [1 post] 5 months ago
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Great article.
Not usually brave enough to tackle this level of change and risk it all not working together. Thanks for the info. JIMTHEBIKEGUY wish I read your comments first. Important to have the screw on correct position. I had it reversed and was anxious when nothing seemed to fit.
1=got the ultegra derailleur for a reasonable price online (same as 105 retail)
2- XT 11-40t cassette That 40t is huge compared to original 32t!
3- Prefer SRAM chains with power link.
Basically, it all fits and works on my Raleigh Tamland with 34x46T crankset. Saving old cassette for commuting or winter road rides.

Jimthebikeguy.com wrote:

To summarize;
Check your rear mech is as above
Shove the b screw all the way in
Fit bigger cassette
Reconfigure your rear limit screws and cable tension
Slam your front mech down a few mm
Fit subcompact chainset
Fit new chain
Reconfigure your front limit screws and cable tension.

Top job. May not work on every bike though, none of this is guaranteed, hence Shimano having such restrictions.

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whizwith [2 posts] 4 months ago
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I had my LBS put on an XT M8000 11-40 on my Lynskey R260 R8050 Di2 setup . I was hoping to use an FSA 48/32 up front, but the frame can't do it with the Di2 wires in the BB. But the LBS said they could replace the 50 with a 46. So I have 46/34 up front, and 11-40 in the back. I need to go for more than a spin and shall report back but was looking for help - How should I adjust the synchro shifting? Is there a logic to the defaults Shimano uses for the 50/34 11-34 setup I had on there before? If someone can point me to a chart or something that explains the framework, I'd be grateful! Thank you

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