Little chainring smaller than big sprocket.

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JohnW
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Re: Little chainring smaller than big sprocket.

Postby JohnW » 12 Feb 2017, 4:22pm

John and Colin - I'd never had front changing problems before - on triple or double. This recent experience of mine confirms what you both say. It's learning by experience, and I'll know in future.

Thanks for all comments.

atoz
Posts: 351
Joined: 5 Jan 2007, 4:50pm

Re: Little chainring smaller than big sprocket.

Postby atoz » 13 Feb 2017, 11:54pm

I've been using triples since 1999, and found them very useful. It is now fashionable to decry them. I was informed by a well meaning but essentially ignorant person (who shall be nameless) that you don't need triples now there are modern compact chainsets. Obviouly that person had never rode up the bottom of Park Rash while in the saddle- lol. And apparently I should now be using 28mm tyres with fast audax/sportive bikes. Slight problem if you have a 32 year old audax bike if you want to use full mudguards with some mud clearance.

I shall keep on using triples with 23mm tyres (I have been using 23's for the last 30 years, and amazingly no ill effects- who'd have thought it). No doubt they will become fashionable again- at which point I will probably switch to fixed- lol.

JohnW
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Joined: 6 Jan 2007, 9:12pm
Location: Yorkshire

Re: Little chainring smaller than big sprocket.

Postby JohnW » 14 Feb 2017, 12:24pm

atoz wrote:I've been using triples since 1999, and found them very useful. It is now fashionable to decry them. I was informed by a well meaning but essentially ignorant person (who shall be nameless) that you don't need triples now there are modern compact chainsets. Obviouly that person had never rode up the bottom of Park Rash while in the saddle- lol. And apparently I should now be using 28mm tyres with fast audax/sportive bikes. Slight problem if you have a 32 year old audax bike if you want to use full mudguards with some mud clearance.

I shall keep on using triples with 23mm tyres (I have been using 23's for the last 30 years, and amazingly no ill effects- who'd have thought it). No doubt they will become fashionable again- at which point I will probably switch to fixed- lol.


I started using triples in about 2004, and had no problems - many, many moons ago (1960s/70s) 36/50 was a commonly available double alternative to 42/52. 36/50 was about the same as many 'compact' lash-up of today - they say there's nothing new under the sun! Among my cycling colleagues it was 42/52 which prevailed - for decades. I never subscribed to the 'compact' ratios. It's the middle ring now that gets most of my mileage - even now that I'm down to a 36Tmiddle. The problem was my own setting up, I think I was being a bit clumsy.

I never get out of the saddle - I've found that if the saddle position is right I don't need to, and the time when I began to think that I did need to get out of the saddle was the time that I learned the need for a granny ring! As a bonus, I find the lower gear easier on the knees.

I don't know who's telling you to use 28mm tyres - use what's best for you. I ride 25mm Gatorskins in my 1981 frame and can't tell the difference from 23mm Paselas. Ride what you like atoz.

hamster
Posts: 3175
Joined: 2 Feb 2007, 12:42pm

Re: Little chainring smaller than big sprocket.

Postby hamster » 14 Feb 2017, 12:27pm

I've had absolutely no trouble with this in MTBs - nor does anybody else.

I even run a 24/39/48 triple with a Campag 13-26 with no bother in a full Campag setup, so I think it is a problem with mech setup (toe-in) and also indexing front shifters.

JohnW
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Re: Little chainring smaller than big sprocket.

Postby JohnW » 14 Feb 2017, 12:35pm

hamster wrote:I've had absolutely no trouble with this in MTBs - nor does anybody else..................


By jove hamster - you've done a helluva survey to ascertain that!

hamster
Posts: 3175
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Re: Little chainring smaller than big sprocket.

Postby hamster » 14 Feb 2017, 1:18pm

MTBs have run this configuration for 30 years - if there was something inherently problematic we would have heard by now... :wink:

Indexing the front derailleur seems to be the root cause of lots of problems, which is why I run Campag shifters.

reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: Little chainring smaller than big sprocket.

Postby reohn2 » 14 Feb 2017, 2:34pm

IMHO the unshipping/derailing of the inner ring on triples with a smaller ring than the largest on the cassette isn't an inherent problem,if the drivetrain is set up properly,but a very occasional one which most people may never encounter,indeed I ran 22/32/42 and 44 on MTBs and 24,26 and 28/34 and 36/46,48 and 50 on touring bikes for 20 years without such issues that I can remember.
However once we'd derailed the tandem with the chain stuck fast on the S/T axle with paint chewed off the R/H chainstay of a very expensive and newish frame,in 35+ degree sweltering heat in the middle of a Portuguese desert without shade of any kind just a few cacti for company.
Then spending the next half an hour+ trying to extract the bl@@dy thing debarking my knuckles on the teeth of the offending chainrings,before getting it free,the experience settles in an indelible part of the memory bank.As a result one tends to look at ways to stop Mrs R2 being introduced to a whole new vocabulary she hadn't heard from me before as I bled onto the red sandy soil :shock: :?

N-gear Jumpstop was that solution and was fitted to all my bikes as a result :)

Note:- derailing double c/sets doesn't have the same problem triples have,as there's plenty of room to get the chain back on,more often than not without stopping by using the front changer.
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rjb
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Re: Little chainring smaller than big sprocket.

Postby rjb » 14 Feb 2017, 2:50pm

I suspect most people with tandems have experienced chain derailing. I once had a poor shift which bent the small chainring a 28 tooth strong light 99. The rings weren't very robust. I now supplement my chainrings with a chain stop and a homemade anti chain suck plate as I have also had that happen as well, dragging the chain back up between chainset and chain stay. Fortunately on that occasion I was only 2 miles from home so we walked and freewheeled home. :(
At the last count:- Focus Variado, Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin, Raleigh 20, Falcon K2 MTB dropped bar tourer, Longstaff trike conversion on a Falcon corsa. :D

reohn2
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Re: Little chainring smaller than big sprocket.

Postby reohn2 » 14 Feb 2017, 3:38pm

rjb wrote:I suspect most people with tandems have experienced chain derailing. I once had a poor shift which bent the small chainring a 28 tooth strong light 99. The rings weren't very robust. I now supplement my chainrings with a chain stop and a homemade anti chain suck plate as I have also had that happen as well, dragging the chain back up between chainset and chain stay. Fortunately on that occasion I was only 2 miles from home so we walked and freewheeled home. :(


Tandems put enormous strain on the drivetrain especially in hilly terrain,we too have bent a chain a couple of times(straightened with a borrowed adjustable spanner).
On one occasion we bent a cassette cog,a 9sp XT cassette,No3 of the largest 7 mounted on an Alu carrier,something I've never done on any solo.I was able to straighten it with long nosed pliers borrowed from a garage.
Another mental note,don't use lightweight stuff on tandem drivetrains :wink:
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I cycle therefore I am.

JohnW
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Location: Yorkshire

Re: Little chainring smaller than big sprocket.

Postby JohnW » 14 Feb 2017, 5:07pm

hamster wrote:MTBs have run this configuration for 30 years - if there was something inherently problematic we would have heard by now... :wink:

Indexing the front derailleur seems to be the root cause of lots of problems, which is why I run Campag shifters.


No-one, least of all me, has said there's an inherent problem. Dunno about the indexing issue - never used it - not necessary - I hadn't set my lash-up accurately enough - I've said so.

I wish I'd never bothered.

Manc33
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Re: Little chainring smaller than big sprocket.

Postby Manc33 » 9 Mar 2017, 10:19pm

The "Ultegra" R773 front mech (or the R443) can be used with a MTB left shifter, but it has to have the cable loose when on the granny (but who cares, it works). I had the R443 and R773 front derailleurs both working fine on a 52-38-24 chainset with an XTR left triple shifter. Doing this gives you a huge gear range / or allows you to have a bit of a smaller low sprocket which of course gives slightly nicer gearing where cadence is concerned. The R773 is a 10-Speed mech but i had no problems using a 9-speed chain (with 8-speed cassette).

On a totally different setup that was all MTB, I found turning the mech in at the back a bit (as opposed to the outer plate of the mech being parallel with the outer chainring) was the only thing that fixed the problems I was having with it shifting down to the granny, it simply refused to no matter what.

Maybe you're not meant to run the FD that way but I have had the chainline at 52mm and it causes even more problems. I put it back to 50mm again and turned the FD in at the back, seems to work, touch wood. Just by putting the chainrings out 2mm more than they should be, I had it randomly slipping on the outer (about one in ten shifts) presumably because the chainring is 2mm further out than the FD expects.

From my experiences the last thing you want is the chainline off, even by 1mm.
Only weird bikes are interesting anymore.

raj
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Joined: 22 Feb 2017, 11:11pm

Re: Little chainring smaller than big sprocket.

Postby raj » 18 Mar 2017, 12:24pm

Have just read over this subject, but not enough familiarity with bike bits to follow it all. I'm in about the same category of requiring increasingly larger rear relative to front. I have 2 road bikes with 'standard' 105 11-speed compact chainrings. One one I have replaced rear 11-32 with SRAM 11-36 + Roadlink and it works fine, although chain is quite slack on small/small (easy to forget which front cog is engaged), and there is slight hesitancy in engaging smallest 2 cogs on cassette but it gets there. I'd like to try 11 - 40 on my other bike (105 50/34 chainring) but LBS who fitted 11 - 36 doesn't think it will be a success, and as it's a carbon frame I don't want to risk worst-case-scenario disaster. I haven't considered changing front chainrings though, either for a smaller inner, or a swap-out for a triple. Don't even know if it's possible. Very unlikely front shifters will work with a triple, but what are my options here? Seems from above that some of your have successfully replaced double with triple. Cost is a factor for me, but not prohibitively so if it gets me significantly fewer inches.

landsurfer
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Re: Little chainring smaller than big sprocket.

Postby landsurfer » 18 Mar 2017, 12:28pm

On a similar post recently i also discussed the issues around chains dropping. My solution was to buy a traditional full tooth form dural sprocket from SPA ... not dropped a chain since. 38 front, biggest on block 32 ...
The Road Goes On Forever ...

Manc33
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Re: Little chainring smaller than big sprocket.

Postby Manc33 » 29 Mar 2017, 3:52am

I ran a 52-38-24 (on 130 BCD /74 BCD) and got away with it (with 11-32t cassette). I loved that setup (gear range). Back on MTB I have toyed with getting a 20t to replace the standard 22t inner, but I always find tales of how not a single one of them can realistically clear the bolts @ 64 BCD. I have seen on with Shimano HG on it though so maybe it does work?
Only weird bikes are interesting anymore.