Is cross-chaining disastrous? Find out what the manufacturers say

fenix wrote:

But why cross chain anyway ?  The ratios are duplicated elsewhere in the gears anyway so there's really no need.

 

I only do it by accident - I'd not do it intentionally. 

Just out of interest, how do I work out the ratios so that I can figure out where on the rear cassette I should be moving down to the little ring/ moving up to the big ring?

davel wrote:

@woldsman: that's an excellent discription of what you do and don't do, but less satisfactory is the why. You're not on your own there.

I don't think anyone's saying they cross-chain for the sake or love of it. The two camps seem to be 'I avoid cross-chaining' and 'I don't avoid cross-chaining - so what?'.

It's not as if cycling's received wisdom isn't thrown out of the window every now and then (fatter, lower pressure tyres being a recent rewriting of it), so just saying something's a bad idea doesn't float, in these days of easy measurement.

If you avoid cross-chaining: why?

I have to admit to being completely unaware of the cross chain rule and have learnt a lot from this thread.
The most shocking revelation to me was the amount of cross over between the small cog and big cog.
So I would pose the question: If crossing your chain is not a bad thing why is there such a large amount of duplication between the small cog and big cog?

Rixter wrote:

Its interesting that the two companies with the smoothest, most precise chains and chainrings are not recommending cross-chaining. The two companies that don't manufacture as strict tolerances don't seem too concerned about it. 

Personally I'd go with the Shimmy & Campy recommendations.

That is interesting. How are you measuring smoothness and precision? Have any measurements you'd care to share?

Pasley69 wrote:

Has anyone done any definitive lab tests under controlled conditions? Shouldn't be too hard - just time-consuming and a tad expensive...

Cheers

Adrian

I've heard of only one study.  It was mentioned on the CTC forum where a bloke who seems to know his stuff discredited it.  I'll have a fish around later...

davel wrote:

@woldsman: that's an excellent discription of what you do and don't do...

Oh, thanks.

davel wrote:

... but less satisfactory is the why.

Oh.

davel wrote:

If you avoid cross-chaining: why?

I note that even the position taken by Sheldon Brown (may he rest in peace) on cross-chaining has been revised.  I wonder if to his original words "The worse the chainline, the worse the mechanical efficiency of the drive train" the sentence  "though research has shown the loss to be minor, at least with modern, flexible chains" was added after his death. 

I'm prepared to accept that increasingly skinny chains will flex more laterally without the world coming to an end, but as I say I'll put together some stuff on such research that I've read about on the other forum.  It is an interesting topic, isn't it?

philtregear wrote:

chains are chains and putting them under unneeded stress will prematurely wear them. SRAM are shameless in taking this as an opportunity to market their front derailluers. Pros have a ready supply of high quality components and mechanics to replace them.  I dont.

It is a stateement of the bleedin obvious that cross chaining should be avoided, butyit should not spell disasterif you ocassionally do it.

Eh? You're accusing the company at the forefront of 1x chainsets of shamelessly plugging front derailleurs? Think that one through.

It might be 'a statement of the bleedin obvious' and 'a chain' might indeed be 'a chain' but where's the actual argument? It's this kind of noddy 'common sense' that's leading me to think this pearl of wisdom is an old wives' tale. By how much does cross-chaining diminish your power or efficiency, or wear your gear out more quickly?

Besides, selling components that aren't up to abuse, then encouraging punters to abuse them, is a piss-poor business model in a competitive environment - especially when Shimano must have the lion's share of OEM components? If they really don't stand up to the wear they say they will, it'll spell the end of SRAM.

The alternative perspective might be to suggest that Shimano and Campag are encouraging punters not to subject their delicate componentry to some real world harshness.

whobiggs wrote:

As a bike mechanic I often see the results of cross chaining, the wear and tear is dreadfull. Absolutely every part is running at an angle and thus getting more strain and less efficiency. One other point I haven't seen mentioned is the fact that there is an overlap in the gears meaning there will be a more suitable and efficient gear in there somewhere so why do it?

Yeah, people have mentioned it. And it's not as if cross-chainers (myself included) prefer cross-chaining: it's more that if it's one shift to do it for a while, to get over a short ramp or whatever, or fish around with 4 shifts, it'll do. So that's why it's done - sometimes it's just more convenient and momentum-maintaining.

Even if that more efficient ratio is available - how much more efficient are we talking? My bet would be you lose jack-all through cross-chaining.

What additional wear and tear is obviously attributable to cross-chaining?

WolfieSmith wrote:

I used to be in a club where the old sweats would change onto the small ring in late October and not use the big ring again until the chainys started in spring. They'd spend all winter tutting at those that used the big ring and making gloomy prognostications about averaging faster than 16mph over 60 cold miles....

A bunch of us started going out in the big ring and blasting 40 mile intervals  instead. It soon became a committee issue and we ended up leaving the club. 

I run a compact these days so tend to use only a couple of cogs on the back anyway on most rides.

fascinating eh?  

 

 

Doom and gloom seem to be part and parcel of hobbies and various ways of practicing them. A couple of my other hobbies are photography and playing the guitar. Fuck me, there's some pedantic bastards in the photo world. I remember being one of the first to get a proper digital SLR and for a few years the die-hard film lot mumbled on about inferior quality etc. A few years later they'd joined the gang except they mumbled on about anyone who didn't have the latest cutting edge DSLR and your gear was more important than your pictures. 

Same with guitars. You can't play this style with that neck or those humbcuckers or that amp. No shredding on Jaguar please, don't use a digital effects pedal, don't self teach, always get a teacher. 

Same with cycling. 

ClubSmed wrote:

Right, so I think I have got it now.
This is the synopsis of what I think I have learnt from this:

• There is a lot of (near as damn it) duplication on the gears on the hub between the crank cogs on a double.
• When you get to around mid way on the hub you should change the crank cogs before proceeding further.
• An exception to this would be if you did not have the time to think and co-ordinate this change without losing momentum and its only a short climb.
• Ignoring the crossing the chain rule will cause componants to wear out faster (how much and which is debatable) but if you can live with that then thats fine.
• Crossing the streams of proton packs is a definate no no unless you are trying to save the world

Do I have this right?

Some people ride bikes.

Some of those people have perfectly efficient bikes, have perfectly efficient riding positions and styles, have the perfect power/weight ratio for their height, have planed their heads into cone shapes, shave their legs every hour and ride in the nude. These people only ever ride downhill with a tailwind and never EVER crosschain because it is inefficient, except they can't reasonably demonstrate this last point.

Some people's components are protected from the accumulation of in-ride road shit via the power of positive thinking. They take their components off after every ride, bathe them in unicorn milk, and tuck them up in bed with a bedtime story, then re-lube them in the morning with dodo feather oil because it increases their life, but they can't reasonably demonstrate this last point.

Then there's the 'just ride/ignoramus' group. Their carefree attitude makes them more attractive, and all that inefficient riding with bad components means that they do three times the work, so they are all Brad-Pitt-in-Fight-Club ripped. They invest all the spare time they have from not fretting about efficiency or component life in getting 'action', but they can't reasonably demonstrate this last point.

Do what makes you happy (or, if you're one of the joyless drones from the first two groups, enables your 'simulate happiness' program to be run).

dottigirl wrote:

Y'know the Shimano shifters with indicators on?

Lots of snobbery against them, but I think they are/were a good idea. Not only did it prevent cross chaining (as it's easier for me to see something on the shifters in front of you than glancing down) but I found it useful to help newbies. Saying to keep the indicators in reasonably the same place on meant they didn't take their eyes off the road to figure out what gear they're in.

Always thought it was a shame they didn't install something similar in higher end groupsets. I still don't like looking back to check which gear I'm in.

I got the transmitter for the di2 the other day, which does exactly this, only vastly more expensively. So far all I've used it for is punishing myself by not allowing myself to use 34x32 for anything, otherwise I won't feel the benefit on a big hill. Like not wearing your jumper indoors.

jimc101 wrote:

How does this article, updated

 

by Mat Brett March 24 2017
 

differer from the orginal one published 3 months ago?

It has March 24 2017 on the top. Obviously. 

huntswheelers wrote:

From the greasy end of things.....  we mechanics eliminate as much rub and noise as possible and sometimes there is none at all at the extremities... when they leave the workshop.... how you ride is your call....  

That's about it, really

Sjl wrote:

Back to Jerome's comment, when cross chained the transverse component of the force applied to the rear cog by the chain is lost to friction and heat. If you were in big/big then this loss could be roughly 4cms/35cms or roughly 10%, its simple physics and i think is covered in the bicycle science publications pretty comprehensively ( where they then argue hub gears arent so bad compared to a cross chained derailleur setup)

 

What would be really useful is a magazine to do some scientific tests using chainset and hub powermeters to measure the differences in various gear combinations.

The manufacturors will never admit to to 10% worst case losses because it makes their products look bad. Compacts were introduced to save money over triple setups but are really really bad when it comes to befinners cross chaining and snapping chains and dropouts.

 

 

 

 

If it's so comprehensively covered, why have we got to 107 posts without someone linking to one such killer study?

(my own disclosure:- I think it makes bugger-all difference to overall efficiency and I can't be arsed Googling for a link to a study that would kill my argument)

Darren C wrote:

A couple of things that have yet to be mentioned;

Firstly, as I am naturally a 'spinner' (have a high cadence) I very rarely need the large ring on my compact double UNLESS I am pedalling over 25mph! Yes, we are all different individuals and anything below 85rpm feels such hardwork to me.

Finally, using the large ring might be lower friction-wise, but what about the actual force needed on the pedals? in my mind the smaller ring needs lesss force due to leverage principles (e.g. when using a wheelbarrow for example, when the weight is closer to the wheel (bottom bracket/chain tension) and the handles are further in distance from this point (crank arm/pedal) it is easier to lift. So for the same load, the small ring generates more torque and it then follows that for the same gear inches it requires less force on the pedals, how much does the greater friction reduce this advantage? also the momentum of the cranks and the mass of my legs spinning at high revs provides a sort of flywheel, making any change in terrain easier to float over. Combined with smaller gaps between the next gears in either direction I find this much more comfortable, but each to their own!

For any given gear ratio (which actually is a leverage ratio from crank end to effective wheel diameter) there is no difference in the pressure required on the pedal to go at a given speed. regardless of whether you're in the big ring or little ring. 

Gozzy wrote:

How often is this article gonna get recycled?

Once more, at least.

madcarew wrote:

Does anyone know any figures that show the loss of efficiency on cross chained? I suspect it's a lot less than shaving your arms.

Pros seek a different efficiency than I.
I'm nowhere near consistency of pro Wattages, etc yet I pay my own servicing.
Loss of efficiency with a view per upon a pro bike could include loss of power output consistency thus may as well cross chain and maintain momentum with fewer torque reductions to shift front chainwheel as torque reduction to shift axle cog is quicker and neater (without assumption nor care whether they need to nor bother to reduce torque momentarily).

Whereas a commuter that absorbs servicing costs via own pocket and off time might not want to sharpen their wheel teeth as quickly. Hence a new bike lasted me 12 years on same chain, cogs; ridden ever second day about 2 years worth, carrying tools in backpack. Given to a friend 12 years later with understanding that top ratio isn't slipping but looks/feels due to jump if ridden daily after about half a year. Simple 2*7 or 2*6.. Thinking it was a 6 speed. When gifted, mate said something similar as,
' Fark it's quick. '

Efficiency versus wear is why I'm with habit to jump ratios and spin rather than use preferred ratios as per efficiency of power output versus speed and momentum.

Yet who cares.. Chains and cog are recyclable, last ages if cross chained or if crab walked and like read above in comments regarding small-small; if you can hear grinding.. ... .. ... Umm grin if you want too, you'll lighten your pockets hence sort of go faster being lighter weight..
sort of easy enough to crab walk a chain, once you've on a straight who cares and hill climbs you're spinning earlier hence easier but slower than a pro.
Worked a couple of years on my stolen bike too. Bought a shipload of spare cassettes planning abuse of 1-2 yearly but lasted 2 years on original set. Probably 6 months of riding 30km daily. A 53 torquing a sequential ratio smaller cog 9speed, 39 torquing a 2 tooth change per shift larger cog 9 speed. Didn't wear much and hills dropped back early or I couldn't climb.

Pros make it look easy. They'd know better acceleration ratios due to pack attacks

ClubSmed wrote:

fenix wrote:

But why cross chain anyway ?  The ratios are duplicated elsewhere in the gears anyway so there's really no need.

 

I only do it by accident - I'd not do it intentionally. 

 

Just out of interest, how do I work out the ratios so that I can figure out where on the rear cassette I should be moving down to the little ring/ moving up to the big ring?

I have a spreadsheet somewhere, and there are a number of online gear calculators available, but here is just one I use: 

http://cycleseven.org/bicycle-gear-inch-calculator

It's worth taking a few minutes to jot down the figures for your particuar bike(s).

ClubSmed wrote:

davel wrote:

@woldsman: that's an excellent discription of what you do and don't do, but less satisfactory is the why. You're not on your own there.

I don't think anyone's saying they cross-chain for the sake or love of it. The two camps seem to be 'I avoid cross-chaining' and 'I don't avoid cross-chaining - so what?'.

It's not as if cycling's received wisdom isn't thrown out of the window every now and then (fatter, lower pressure tyres being a recent rewriting of it), so just saying something's a bad idea doesn't float, in these days of easy measurement.

If you avoid cross-chaining: why?

I have to admit to being completely unaware of the cross chain rule and have learnt a lot from this thread.
The most shocking revelation to me was the amount of cross over between the small cog and big cog.
So I would pose the question: If crossing your chain is not a bad thing why is there such a large amount of duplication between the small cog and big cog?

closer gear ratios, shorter mech cage, shorter chain

hawkinspeter wrote:

Gozzy wrote:

How often is this article gonna get recycled?

Once more, at least.

It's a bit like when women tell people they're 29....

Woldsman wrote:

ClubSmed wrote:

fenix wrote:

But why cross chain anyway ?  The ratios are duplicated elsewhere in the gears anyway so there's really no need.

 

I only do it by accident - I'd not do it intentionally. 

 

Just out of interest, how do I work out the ratios so that I can figure out where on the rear cassette I should be moving down to the little ring/ moving up to the big ring?

 

I have a spreadsheet somewhere, and there are a number of online gear calculators available, but here is just one I use: 

http://cycleseven.org/bicycle-gear-inch-calculator

It's worth taking a few minutes to jot down the figures for your particuar bike(s).

Thanks for this, I have just done the calculations and I am shocked at the amount of duplication that there is on my 53/39 11-32 11 speed set up

ClubSmed wrote:

davel wrote:

@woldsman: that's an excellent discription of what you do and don't do, but less satisfactory is the why. You're not on your own there.

I don't think anyone's saying they cross-chain for the sake or love of it. The two camps seem to be 'I avoid cross-chaining' and 'I don't avoid cross-chaining - so what?'.

It's not as if cycling's received wisdom isn't thrown out of the window every now and then (fatter, lower pressure tyres being a recent rewriting of it), so just saying something's a bad idea doesn't float, in these days of easy measurement.

If you avoid cross-chaining: why?

I have to admit to being completely unaware of the cross chain rule and have learnt a lot from this thread.
The most shocking revelation to me was the amount of cross over between the small cog and big cog.
So I would pose the question: If crossing your chain is not a bad thing why is there such a large amount of duplication between the small cog and big cog?

The most shocking revelation to me was my spelling of 'description'. Oh the shame.

hawkinspeter wrote:

Gozzy wrote:

How often is this article gonna get recycled?

Once more, at least.

I come from the future to present you with 2019's Mystic Meg award.

So, basically, this whole article and many of the comments boil down to people being apprehensive about front shifting. My view is: just get the front mech sorted (your LBS will love to help you here) and embrace the pleasure of shifting a well-tuned setup (like driving a car with a nice manual box).

On my ten minute commute to work (I carry the bike up to the office so can bring the nice one), I'm shifting the front mech half a dozen times. Particularly pleasurable is the "double sweep", where you're going from small to large on the front and two down on the back with a simultanous inward sweep of both shifters. Nice.

jerome wrote:

I always thought, and still think, that if the chain is doing an angle alpha relative to being straight, and you apply a force F to the pedal, then F*sin(alpha) is "lost", well, more properly said does not contribute to the foward movement. Is it neglectible compared to other sources or inefficiency?

Did not learn much with that article.

The first question Jerome, is what is it 'lost' to? Heat? Deformation? wear of the mating surfaces? You are talking about force, and if it requires force to deform the chain to that extent, then yes you would lose Fsin(alpha), but your idea lacks acknowledgement of the chain's structure. The losses are orders of magnitude smaller than you suggest.

madcarew wrote:

The first question Jerome, is what is it 'lost' to? Heat? Deformation? wear of the mating surfaces? You are talking about force, and if it requires force to deform the chain to that extent, then yes you would lose Fsin(alpha),

I know there is no exchange of energy if a force is applied but everything remains static (object placed on a table, magnet stuck to a piece of iron). But I also know by experience that my body does not work the same, and if I apply force on a wall, I loose energy and my arm fatigues even if the wall does not move. So even if the chain/sprocket deform elastically (or do not deform at all) and there is no heat dissipation, that F.sin(alpha) does not look to be completely free for my body.

madcarew wrote:

but your idea lacks acknowledgement of the chain's structure. The losses are orders of magnitude smaller than you suggest.

That is a complete unkown to me, really, and I would be happy to see figures.

madcarew wrote:

jerome wrote:

I always thought, and still think, that if the chain is doing an angle alpha relative to being straight, and you apply a force F to the pedal, then F*sin(alpha) is "lost", well, more properly said does not contribute to the foward movement. Is it neglectible compared to other sources or inefficiency?

Did not learn much with that article.

The first question Jerome, is what is it 'lost' to? Heat? Deformation? wear of the mating surfaces? You are talking about force, and if it requires force to deform the chain to that extent, then yes you would lose Fsin(alpha), but your idea lacks acknowledgement of the chain's structure. The losses are orders of magnitude smaller than you suggest.

Spot on madacrew. Not for the first time, jerome has demonstrated that a little knowledge is a dangerous thing. His F. sin alpha formula merely demonstrates that the first tooth on each cog experiences a sidways force of F.sin alpha. But this is a force, not a loss. It is friction on these two teeth controlling the direction change which cause the increased losses. To understand the loss, you need to multiple this force by the coefficient of friction between chain link and tooth, then multiply by the contact area as the chain disengages from the tooth. Not a trivial calculation because the tooth/chain area change is quite complex during disengagement. Nevertheless you can see that irrespective of Jerome’s force, if you get yourself a nice perfect ceramic, frictionless tooth, then the losses would be zero. For a practical chain/tooth combination, the losses would be very much less than F.sin alpha, unless of course you forget to lube the chain.   

Griff500 wrote:

"a little knowledge is a dangerous thing"

OMG I am dangerous

It is only dangerous if you thing that that amount of little knowledge is the full truth, which I never implied to have in that particular case.

I also noticed you reworded your comment to make it more correct, and in fact it is rather convincing till the final part that says "the losses would be very much less than F.sin alpha" that spoils a bit the demonstration.

However I suspect that, for the human body, applying a force always requires energy, even if that force produces no work. See my previous comment about pushing a wall. This is no more newtonian physic here, this is about what happens in the human body to produce the said force.