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Single ring and wide-range cassette drivetrains are gaining popularity, so is this the end for the front mech

The drivetrain on a modern road bike has evolved loads since the early days when a rod was manually operated to move the chain onto a different sprocket, with electronics now commonplace and ever wider range cassettes providing enough gears to tackle even the steepest mountain climbs.

Most modern road bikes combine two derailleurs to move the chain across the rear cassette and front chainset, and it works well thanks to many years of product development. We probably take them for granted. But there's a move in some parts of the cycling world to simplify the drivetrain and it threatens the future existence of the front derailleur.

The arrival of SRAM’s 1x11 drivetrain a few years ago, a groupset which ditched the front mech and instead combined a single chainring with a wide-range cassette, provided another path. Such groupsets have become hugely popular on mountain bikes and we've seen cyclocross and adventure bikes also being specced with the company's groupset in recent years but could the same happen to road bikes?

What are the benefits on a road bike?

The simplicity is certainly appealing. With just one shifter, changing gear is much more intuitive than having to manage the front and rear derailleurs. For beginners, that's going to be an obvious benefit. There’s one less component to fail as well (though front derailleur failures are rare) and on bikes designed for wider tyres, removing the front derailleur can provide additional clearance around the rear wheel and seat tube area.

Read more: Beginner's guide: understanding gears

sram rival 1 first ride2

A short history of the front derailleur

Early users of double chainsets didn't even bother with front derailleurs; they pushed the chain from the large to small chainring with their heels at the bottom of a long climb, then stopped at the top of the hill to manually lift it back to the big ring. In the 1930s, French cycle tourists began using mechanisms to move the chain, as they realised being able to change gears was useful on the flat as well as when you had a long climb ahead.

Front derailleurs of the 1930s were usually actuated by cables; rod-operated front derailleurs appeared in the 1940s, and provided very quick and efficient shifts. You had to reach down towards the bottom bracket to operate them, which looks awkward to modern riders who are used to brake/shift levers, but was reportedly quite straightforward.

Read more: First Ride: SRAM 1x Road

Since then, the front derailleur really hasn't changed much at all. It's still a basic component, comprising two metal plates that shove the chain across the chainrings, and the stiffer those plates the better the shifting. But making plates stiffer by making them thicker also adds weight, so gear makers have added ramps and pins to the chainrings, bringing a real improvement in front shifting performance. The biggest recent development has been the addition of a motor in the electronic systems made by Shimano, Campagnolo, SRAM and FSA.

The 1x charge – the industry speaks

But the cycle industry is in a great period of technological development at the moment and everything is up for change. Chainsets have evolved from triples to doubles over the years with loads of configurations available, but a definite trend towards lower ratio setups like a compact, semi-compact and most recently, sub-compact. So if lower gears are popular, why not go all the way and use a smaller single ring?

For mountain biking, a single ring chainset makes a lot of sense. Changing gears is easier with just one gear shifter, there's one less thing to malfunction, mud and ground clearance is improved, weight is lowered and suspension designers are freed from the limitations of having to factor in a front derailleur when locating pivots. And any loss in gear range is compensated for by a wide-range cassette, with SRAM’s introduction of a 10-42t cassette and more recently 10-50t with its 12-speed Eagle groupset.

SRAM has been instrumental in the popularity of single ring drivetrains, but SRAM’s Global Drivetrain Category Manager Ron Ritzler doesn’t think fans of the front derailleur need to worry just yet.

"Will the front derailleur disappear? Probably not yet as there are certain users, like some elite athletes, who need the range and the steps to perform at their best – but can it kill the front derailleur for users who spend their time in cyclocross, commuting, adventure riding and in events where fast precise single ring performance is preferred; heck yes,” he tells us.

“We still make front derailleur and 2x rings that work really perfectly, but we love the fact that there are some many people using road bikes in new ways that make 1x the right choice."

While SRAM has been cheerleading the benefits of single ring drivetrains, Shimano isn’t really embracing it. Shimano’s Ben Hillsdon says the versatility of the double ring setup is just too good to ignore.

“Essentially the front derailleur doubles the number of gear ratios available to a rider, and, therefore, gives riders smaller steps in shifting between their biggest gear and their lowest gear,” he says. “That means riders have a wider range of gears, a smoother pedalling experience and their cadence (ie leg speed) can stay constant.

“That, in turn, brings a physiological benefit as muscles and joints are saved from being overworked, which can be crucial when it comes down to the sharp end of a race. The versatility of a double-ring setup is that you can go anywhere without compromise. However, for those riders choosing simplicity, our strategy is to offer drivetrains that can be set up in many different ways for different styles of riding.”

Read more: Your complete guide to SRAM road bike groupsets

Polygon Bend CT5 - crank.jpg

But a front derailleur gives you more gears, right?

One of the biggest advantages offered with the introduction of the front derailleur was massively increasing the range of gears. That was an obvious advantage with a 5-speed cassette many decades ago. Over the years, the number of sprockets on the cassette has increased and is now up to 11 (and 12 in the mountain bike world).

Not only has the sprocket number increased, but the size of the sprockets has gone up: most racers predominantly used 11-23 cassettes a few years ago, but 11-28 is now common in the pro peloton and many sportive bikes now come with 11-32 cassettes.

Of course, removing one of the chainrings reduces your available range so to combat this SRAM introduced a whopping 10-42 cassette. It was instrumental in winning over mountain bikes as it was possible for a single ring drivetrain to offer nearly the same gear range as a conventional compact drivetrain.

Read more: SRAM Rival 1 review

How does a single ring drivetrain compare to a conventional drivetrain? Favourably, if you look at the numbers. Combine a 44t single chainring with an 11-36 cassette and you have a gear range from 33 to 108 inches. That’s very nearly the same as the 32.8 to 122.7 range that a conventional 50/34 and 11-28 setup provides, typical of many sportive bikes these days.

You can adjust the size of the chainring and the cassette to tailor that gear range to suit the geography of your local terrain and riding style, whether solo touring rides or racing, much like you modify a current drivetrain with different chainsets and cassettes depending on whether you want top-end for racing or low-end for riding in the mountains.

While the gear range compares favourably, where the 1x setup falls short is in the jumps between the gears. This will concern those cyclists who like to be in the perfect gear for the optimum cadence at all times. How big a concern the larger jumps between gears will be to you depends largely on the type of cyclist you are, the sort of riding you do and your terrain. There is much work being done to provide cassettes that can help smooth the transition in the most frequently used gears, with 3T's Gerard Vroomen developing two versions of a 9-32t cassette that looks to be a good choice.

Kinesis Tripster AT - cassette.jpg

So should you ditch the front derailleur?

That depends. There are clear advantages and disadvantages to a 1x drivetrain at present. It’s unlikely we’ll see the front derailleur confined to the history books anytime soon, especially given Shimano’s dominant position in the market. That'll certainly be the case for regular road bikes and especially race bikes where tradition rules.

Where we expect to see single ring drivetrains really start to become a lot more popular is on bikes where the disadvantages are outweighed by the advantages offered by a simplified drivetrain, where the ultimate range isn't as critical and where the bigger jumps aren't as much of an issue.

Read more: Will your next bike be a gravel bike?

We’re talking about cyclocross bikes (where many racers have been going single ring for many years already with home-brewed solutions) and the gravel and adventure bike category where 1x has pretty much established itself as the groupset of choice. But with the likes of the 3T Strada and Whyte Wessex One, two road bikes designed around 1x11 drivetrains, we could be looking at more road bikes devoid of front derailleurs in the future.

Whyte Wessex One

Ultimately, though, the modern groupset is too good for many cyclists to want to make a radical change. But the rise of wide-range cassettes does provide an interesting alternative that will appeal to many cyclists, which means we might see a few less front derailleurs on road bikes in the future.

Do you ride a bike with a single ring drivetrain?

David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.

67 comments

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jterrier [215 posts] 1 year ago
3 likes

Its not quite dead yet (shame) but will be once the next generation of cassettes and hubs arrive to correctly facilitate the range needed. It seems the optimal one will be 12spd, with an xd driver with a 9or10-40 cassette and a 40T ring.

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CXR94Di2 [2276 posts] 1 year ago
2 likes

There isnt the range for a road bike to be truly versatile all-rounder. Yes MTB the simple setup allows just enough range to tackle most climbs/trails.

My own Tripster, I geared down to a MTB setup for primarily climbing mountains. It does this admirably with the gearing. However just recently I was left out gunned on a gradual slope where I couldn't spin any faster than 120rpm. I've fitted a larger outer chainring to bring cadence down for fast low percentage slopes but still capable of climbing mountains,.

I have a XT Di2 setup with 44-28 chainset and 11-40 cassette  4

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Miller [153 posts] 1 year ago
4 likes

Yeah... but modern front mechs work really well and e-groups will even do compensating shifts at the rear to minimise the big jump of a front shift. I'm not seeing much of an issue to be solved for a road bike and do we really want pie-plate rear sprockets?

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antigee [507 posts] 1 year ago
1 like

not anti 1x have it on my shopper/gym bike and works fine, ridden 1x on hire bikes at trail centre and works fine but am puzzled by

Quote:

and do we really want pie-plate rear sprockets?

for years all I've heard is reduce rotating mass - lighter rims, tubeless etc etc 

...so where does sticking all that gearing in the rotating mass really help things or is this a bit like press fit BB's ? sell the advantages but forget the problems because it works ok for the producers?

 

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psling [292 posts] 1 year ago
8 likes

"Is the front mech dead?"

No.

"Is there a future for the front derailleur on modern road bikes?"

Yes.

For those of us who don't aspire to be pro-riders, don't want a dinner-plate cog out back and are happy to just enjoy our riding, then a double or triple up front 'ain't broken and don't need fixing'.

I know things move on and progress can be a good thing; indeed there have been some great developments over the last decade or so but single ring up front for everyone is not one of them.

IMO 

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fukawitribe [2600 posts] 1 year ago
0 likes
antigee wrote:

not anti 1x have it on my shopper/gym bike and works fine, ridden 1x on hire bikes at trail centre and works fine but am puzzled by

Quote:

and do we really want pie-plate rear sprockets?

for years all I've heard is reduce rotating mass - lighter rims, tubeless etc etc 

...so where does sticking all that gearing in the rotating mass really help things or is this a bit like press fit BB's ? sell the advantages but forget the problems because it works ok for the producers?

 

Not pro- or anti- in general, horses for courses etc, but there's little change here. Back of fag packet says something like a Ultegra 11-28 -> XT 11-40 is about 150g and an Ultegra 36T inner ring is around 40g I believe - and take off a wee bit for a smaller big ring. Difference is smaller when comparing something like 105 -> XT or even Deore. Slight difference in mass distribution and moment of inertia with the cogs, but it's really not massive. Overall weight down a bit too as no front mech or cable but meh..

Use 1x if you like, don't if you don't - it's not worth spending much time on.

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Richard1982 [108 posts] 1 year ago
1 like
antigee wrote:

for years all I've heard is reduce rotating mass - lighter rims, tubeless etc etc 

 

 The whole rotating mass thing is largely irrelevant in the world of cycling. The difference (even at the wheel rim) is miniscule, saving 50g from your wheel rims has pretty much the same effect as saving 50g from bottle cage. People will of course argue as it's one of the great myths in cycling.

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mingmong [315 posts] 1 year ago
3 likes

I've 1x11 on my mtb and the cross-chain is indecent.

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Daveyraveygravey [630 posts] 1 year ago
3 likes

In the article it says "ground clearance is improved" (for mtbs).  Why or how is this?  A front mech is several inches above the BB, so where is ground clearance a problem?

I am anti 1x.  It looks shit, and if you are so thick you need " the simplicity" of one shifter, you probably shouldn't be allowed out on your own.  A semi compact chainset and 11 speed Ultegra gives me a perfect set up for riding in the UK.  If I moved to the Alps, I'd get a compact.  

1x for the road - you never have the right gear.  You can't climb steep hills because you can't turn the pedals at 40 rpm.  You can't go downhill fast (or even on the flat with favourable conditions) because you're spinning at over 120 rpm.  And everywhere else you're always not quite in the right gear...

 

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don simon [2617 posts] 1 year ago
2 likes
Daveyraveygravey wrote:

In the article it says "ground clearance is improved" (for mtbs).  Why or how is this?  A front mech is several inches above the BB, so where is ground clearance a problem?

I am anti 1x.  It looks shit, and if you are so thick you need " the simplicity" of one shifter, you probably shouldn't be allowed out on your own.  A semi compact chainset and 11 speed Ultegra gives me a perfect set up for riding in the UK.  If I moved to the Alps, I'd get a compact.  

1x for the road - you never have the right gear.  You can't climb steep hills because you can't turn the pedals at 40 rpm.  You can't go downhill fast (or even on the flat with favourable conditions) because you're spinning at over 120 rpm.  And everywhere else you're always not quite in the right gear...

 

Rubs chin...

Regarding the ground  clearance, is the bb the measure of this, or would we consider it to be the result of a smaller chain ring having a smaller radius because there's no need for a front mech?

Secondly, as long as you're not riding a 53/39, please don't mock the choices of others. riding up Morcuera on a 53/28 is doable, difficult and slow, but doable.

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check12 [243 posts] 1 year ago
1 like

No, yes

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Bmblbzzz [231 posts] 1 year ago
2 likes

 SRAM’s Global Drivetrain Category Manager Ron Ritzler...

"Will the front derailleur disappear? Probably not yet as there are certain users, like some elite athletes, who need the range and the steps to perform at their best – but can it kill the front derailleur for users who spend their time in cyclocross, commuting, adventure riding and in events where fast precise single ring performance is preferred; heck yes,” he tells us.

 

So, single ring transmissions are better in situations where, erm, single ring transmissions are preferred. Very informative, Mr Ritzler. 

 

 

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Bmblbzzz [231 posts] 1 year ago
2 likes

And an addition to the "journalists don't check anything nowadays" file:

"One of the biggest advantages offered with the introduction of the front derailleur was massively increasing the range of gears. That was an obvious advantage with a 5-speed cassette many decades ago."

Did anyone ever make a 5-speed cassette? I really doubt it. I think you might mean a 5-speed freewheel. 

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fukawitribe [2600 posts] 1 year ago
0 likes
Bmblbzzz wrote:

 SRAM’s Global Drivetrain Category Manager Ron Ritzler...

"Will the front derailleur disappear? Probably not yet as there are certain users, like some elite athletes, who need the range and the steps to perform at their best – but can it kill the front derailleur for users who spend their time in cyclocross, commuting, adventure riding and in events where fast precise single ring performance is preferred; heck yes,” he tells us.

 

So, single ring transmissions are better in situations where, erm, single ring transmissions are preferred. Very informative, Mr Ritzler. 

 

 

He didn't say they were better there, just that they could (in his opinion) 'kill' the front mech in cyclocross, commuting and adventure riding and also "in events where fast precise single ring performance is preferred".

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Simmo72 [699 posts] 1 year ago
4 likes

fewer parts (but same price), more chain wear replacements, whats not to like....if you are shimano, sram etc 

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gary p [14 posts] 1 year ago
0 likes
jterrier wrote:

Its not quite dead yet (shame) but will be once the next generation of cassettes and hubs arrive to correctly facilitate the range needed. It seems the optimal one will be 12spd, with an xd driver with a 9or10-40 cassette and a 40T ring.

 

I see it different.  I think 12 gears in a 400% range is too few; some of the gaps too large. And 12 gears in a 444% range would leave some very uncomfortably tall steps between gears.    

When you combine the common 50/34 or 52/36 front cranksets with the ubiquitous 11-28 cassette, you get a range that's well under 400%.  Any serious road 1x system needs to be optimized to replace these set-ups, then have options for wider range.    

When there's a 10-36 or 11-40 13-speed cassette and rear mech, you'll have my attention.   As a flat-lander, I could even get by with an 10-32 or 11-36 12 speed setup, but I don't see that as a viable option for the mass market.   

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The Old Dope [2 posts] 1 year ago
2 likes

Didn't realise I was an elite athlete  3

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Yorkshire wallet [2310 posts] 1 year ago
5 likes

What would probably be more useful to casuals on road bikes would be lower overall gearing.

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tugglesthegreat [104 posts] 1 year ago
1 like
Simmo72 wrote:

fewer parts (but same price), more chain wear replacements, whats not to like....if you are shimano, sram etc 

Nail on head Simmo and the main non-selling point for me.   Currently I feel that I am getting more from a cheaper system like 2 x 11. 

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tugglesthegreat [104 posts] 1 year ago
0 likes
CXR94Di2 wrote:

There isnt the range for a road bike to be truly versatile all-rounder. Yes MTB the simple setup allows just enough range to tackle most climbs/trails. My own Tripster, I geared down to a MTB setup for primarily climbing mountains. It does this admirably with the gearing. However just recently I was left out gunned on a gradual slope where I couldn't spin any faster than 120rpm. I've fitted a larger outer chainring to bring cadence down for fast low percentage slopes but still capable of climbing mountains,. I have a XT Di2 setup with 44-28 chainset and 11-40 cassette  4

I was thinking of getting a 28-40 chain set and fitting a 44 for special events on my Arkose.  Does it work well on a CX bike?

Although 11-32, nothing as bonkers as 11-40!

 

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ChetManley [95 posts] 1 year ago
1 like

I ride both, on the same bike. Both have their uses, 1x is my "off road" set up but it's fine for short road rides.

2x I use on longer road rides but works fine on dirt too, if it's faster terrain or monster climbs two gear ranges is most welcome.

What I'd like is to be able to mix and match Shimano mountain and road parts without extra doohickeys.

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Flying Scot [1005 posts] 1 year ago
0 likes

Will someone make an adaptor so I can just bolt my 42 front ring onto the casette or freewheel to save any waste then?

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Cugel [59 posts] 1 year ago
3 likes

"Combine a 44t single chainring with an 11-36 cassette and you have a gear range from 33 to 108 inches. That’s very nearly the same as the 32.8 to 122.7 range that a conventional 50/34 and 11-28 setup provides.....".

Well, the top end isn't "nearly the same" is it? 108 inches versus 123ish inches...... And what about all the missing ratios in between, where there are now only big jumps in cadence instead?

Mind, I don't know why your avergare MAMIL, commuter, sportive rider or anyone else not an elite racing fellow wants a 123 inch top gear. How many of us can pedal to 40mph? (No, you don't need to do so downhill as you'll go faster if your get tucked and don't disturb the air flow with your pedal thrashes).

Anyroadup, I like a double or a triple chainring to enable the closer ratios at the back. It must be my 55 years of honing the cadence, eh? Strangely I find the gear changing becomes second nature - like 1001 other human operations of mechanical stuff.

What I do find annoying is the lack of cassettes that begin with a 14 or 15 tooth sprocket and end with a 32 or 36. One must have a useless 11, 12 and 13 sprocket ... or buy two cassettes to cannabalise so the ideal sprocket range can be extracted. (Even then, the ramps on the sprockets sometimes suffer a graunch-causing mismatch).

Like the single chainring thing, 11-summick cassettes are just a fashion aping "the professionals" and/or the latest manufacturers marketing gimmick. It all makes work for the landfill attendants to do, I suppose.

Cugel 

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Alb [164 posts] 1 year ago
1 like

"We still make front derailleur and 2x rings that work really perfectly..."

News to me! smiley

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BarryBianchi [418 posts] 1 year ago
0 likes

Magic beans anyone?

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alansmurphy [1916 posts] 1 year ago
1 like

"While the gear range compares favourably, where the 1x setup falls short is in the jumps between the gears. This will concern those cyclists who like to be in the perfect gear for the optimum cadence at all times. How big a concern the larger jumps between gears will be to you depends largely on the type of cyclist you are, the sort of riding you do and your terrain"

 

As a commuter that turned roadie post Boardman it actually took me years to get the hang of this. Always had low cadence (73) ground out a big gear even up the hills. I'm gradually improving but like that I still have that psychotic tendency.

 

My new bike has 11 gears and the cadence difference is unreal that everything feels smoother and I can attack in different ways. My winterised bike with Claris 8 speed I seem to have made the problem worse - I added an 11-34 cassette. When you're in the big ring the jump to that last sprocket is ridiculous and you spin out, you shift back up and it's murder. It's all about the ratios (and the legs)... 

Avatar
gary p [14 posts] 1 year ago
1 like
Cugel wrote:

What I do find annoying is the lack of cassettes that begin with a 14 or 15 tooth sprocket and end with a 32 or 36. One must have a useless 11, 12 and 13 sprocket ... or buy two cassettes to cannabalise so the ideal sprocket range can be extracted. (Even then, the ramps on the sprockets sometimes suffer a graunch-causing mismatch).

Like the single chainring thing, 11-summick cassettes are just a fashion aping "the professionals" and/or the latest manufacturers marketing gimmick. It all makes work for the landfill attendants to do, I suppose.

Cugel 

 

Well, you can get some of the same effect with the newer subcompact cranksets aimed at gravel bikers and cyclocrossers, or going with mountain bike chainrings....assuming your front mech mount has enough vertical adjustment.   

But I do agree that there's a distinct lack of logic with Shimano's 11 speed cassette offerings.   Why are virtually all them anchored with an 11 speed cog?    It means you can't effectively change gearing to the terrain without either chainging front chainrings or compromising some of the utility an 11-speed setup is supposed to give you (either more top gear than you need on a flat course, or not enough top end on a hilly course). 

Ideally, I'd like to have  a close-ratio cassette with a 13T smallest cog for flat routes, mid-range cassette with 12T small cog for rolling routes, and a wide ratio cassette with an 11T smallest cog for hilly routes.  Shimano offers nothing that meets the first requirement, and only an expensive Dura Ace cassette for the second.   

 

SRAM's worse, offering no standard-driver 11 speed cassettes with anything other than an 11 tooth small cog.  

Avatar
reliablemeatloaf [107 posts] 1 year ago
3 likes

It doesn't have to be "all-or-nothing" as the article title might imply. For some, the large jumps in gears will be okay, and they can have 1x; for those that prefer smoother transitions, they can stay with a front mech.

As far as the weight savings, aerodynamics, how much can be saved?? One watt? Two? For 99% of us, it won't make that much difference. Pros will like it, as will their machanics.

The question might be - will the industry still offer front mechs, or will everybody be forced to 1x?

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SteveAustin [154 posts] 1 year ago
2 likes

I found myself riding a 1x9 off road for a while: what i found was i ran out of gears, a lot, and would find myself only having 1 gear i could use at the end of the range, and found myself in the middle of the block for the rest of the time. so i lost a lot of gears somewhere, and was wearing chains at an amazing rate.

so, faster chain wear, faster sprocket wear, less gears. not a system ill be using again. its a gimmick 

Avatar
CXR94Di2 [2276 posts] 1 year ago
0 likes
tugglesthegreat wrote:
CXR94Di2 wrote:

There isnt the range for a road bike to be truly versatile all-rounder. Yes MTB the simple setup allows just enough range to tackle most climbs/trails. My own Tripster, I geared down to a MTB setup for primarily climbing mountains. It does this admirably with the gearing. However just recently I was left out gunned on a gradual slope where I couldn't spin any faster than 120rpm. I've fitted a larger outer chainring to bring cadence down for fast low percentage slopes but still capable of climbing mountains,. I have a XT Di2 setup with 44-28 chainset and 11-40 cassette  4

I was thinking of getting a 28-40 chain set and fitting a 44 for special events on my Arkose.  Does it work well on a CX bike?

Although 11-32, nothing as bonkers as 11-40!

 

 

Yes perfectly, it is at the maximum range on the crankset because the front derailleur cage wont allow anything more.  There is one benefit with XT Di2 is that the electronics wont allow the rear derailleur to cross chain small/small.  It stops the rear derailleur moving onto last 4 sprockets.  This keeps the chain from rubbing on the front derailleur lower section.  Ive now fitted Syncroshift display- that works beautifully.

I tried several front outer chainrings to get the correct fit and look.  I needed longer steel outer crank bolts to create the clearance between the inner and outer rings(steel has shallower heads).

I use an 11-32 cass for general riding, only use 11*40 for alpine type climbs

If you want more info just ask.  

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