'Alpine' Crankset?

[Vaya]

Another thought about making my gearing more efficient - or at least trying to use most if not all the gears that I have on the bike.

Had originally thought about changing the triple crankset to a single ring and running a 1x9 spd set up but I am hesitant to lose a very low gear for those days when everything is against you (wind, rain, heavy load, big hill...)

After seeing this post by Brucey I had another idea:

at the risk of sounding like a heretic, it is sometimes possible to use a triple crankset less the middle ring, with the big ring fitted where the middle usually goes. The net result can be akin to an alpine double.

This can leave the chainline appreciably better on the big ring, and (say) allow a set of double-chainset-only STIs to be used.

On the minus side the bolt heads on the big ring may be a problem (if the big ring can't simply be turned about) so you may need various spacers etc e.g. under the bolt heads on the big ring (if turned) and/or under the small ring (to space it away slightly). The 'Q' value isn't great either.

If a chainset that supported a proper alpine double chainring combination was available at reasonable cost, this kind of workaround wouldn't be required. As it is, those small chainrings you want only come fitted to inner BCDs on triples these days, and both shimano and campag seem to want to stop that too; their latest 'road triples' won't take anything smaller than 30T or so.

Come back stronglight 99, TA cyclotouriste etc; all is forgiven....

cheers

I searched for 'alpine gearing' and as far as I understand it is one large main ring that is used most of the time with one very small ring for the very steep hills, can some one confirm this?

So my thoughts were:

Use the triple Stronglight Impact chainset I currently have, put a 24 tooth ring on the 74 BCD arms, put either a 40 or 42 tooth ring on the 110 BCD middle ring and then put a bash-guard on the outer rings. The reason for this is that it should negate the need for washers and should make the chainset 'look' tidier. This would have a 9 speed cassette as well.

Would this work? Or is it a daft idea?

What is the largest gap between teeth numbers that would work?

I came across the White Industries crankset - they look very nice but also very pricey.

[Brucey]

...Would this work? Or is it a daft idea?

What is the largest gap between teeth numbers that would work?

I came across the White Industries crankset - they look very nice but also very pricey.

You can check the specs but many front mechs for doubles come with a difference spec that allows a convincing alpine double to be used. In reality you don't usually need any more than (say) 18T difference and this allows a wide range of different mechs to cope.

An issue is using a big ring in the middle position if it has bolt counterbores and/or pins/ramps. You might be better off getting a middle ring to use in that position even if it is your 'big ring' in fact.

Other cranksets to look at include the velo orange and Herse models. Both offer an alpine double possibility.

cheers

[Valbrona]

So, a 24 inner and a 42 outer? How many miles of cycling would you have to do before the following kind of occurs to you: 'You know, if I just had something like a 34 in the middle of these two I would have a great spread of gears'. Answer: Not a lot of miles at all.

[tatanab]

Use the triple Stronglight Impact chainset I currently have, put a 24 tooth ring on the 74 BCD arms, put either a 40 or 42 tooth ring on the 110 BCD middle ring and then put a bash-guard on the outer rings. The reason for this is that it should negate the need for washers and should make the chainset 'look' tidier. This would have a 9 speed cassette as well.

Would this work? Or is it a daft idea?

It is fine. I have done this on a Campag triple using 24/40/bash guard with a 12/28 10 speed cassette. It gives me the same gear range (very very nearly) as my triple 24/36/48 with 14/28 on the back. The big advantage is that on the big ring of 40 I have almost the same range as the middle and outer rings combined on the triple but sequentially. So I only use the little ring when I am going to be in the small gears for a while and will need lower than 40 by 28.

Range of a front mech may be a problem. I use a Campag triple mech with Ergo levers which works just fine but Shimano might not like it because Shimano index the front so you need all the ramps etc to help changing. Shimano might also present another problem, especially if using an MTB front mech. The cage is a bit long and when it is set correctly for the chainring you might find that it fouls the chainstay or gear cable if it runs along the top of the chainstay.

Try it with your present chainset (which is what I have done0 and then you might consider buying a new chainset which is designed as an alpine double. SRAM do such chainsets for the MTB market. Because it is a "new idea" they might be a bit expensive at present but the price will come down.

My set up

[Oceanic]

One of these would allow you to set up the gears you are after with a lower Q factor.

http://www.spacycles.co.uk/products.php ... 0s109p2188

[531colin]

So, a 24 inner and a 42 outer? How many miles of cycling would you have to do before the following kind of occurs to you: 'You know, if I just had something like a 34 in the middle of these two I would have a great spread of gears'. Answer: Not a lot of miles at all.

He does have a point, you know.

Twenty years ago, before I needed the very low gears that are common now, I had 13 to 28 on the back, and a 28, 36, 44 triple. I could have had a bigger range of gears, but that was the sweetest transmission to ride. Changing front rings was just like changing at the back, it didn't upset my rhythm. There was no down one at the front, up two at the back in order to keep up with the pedals. Were it not for all the dire warnings about modern F. mechs. being designed for 12T difference between big and middle rings, and the difficulty of getting a middle ring less than 32T, I could be tempted to do the same now....if I had 22, 30, 38 triple, I might even use that ridiculous 11T sprocket that I carry around.........(or is it just a funny-shaped spacer?)

[Oceanic]

Had originally thought about changing the triple crankset to a single ring and running a 1x9 spd set up but I am hesitant to lose a very low gear

If you're going to line up the 40t ring with the middle of the cassette, and use that chainring with all the rear sprockets, it might be a good idea to use a friction shifter to control the front mech. That way you could trim the front mech really effectively.

[Vaya]

It is fine. I have done this on a Campag triple using 24/40/bash guard with a 12/28 10 speed cassette. It gives me the same gear range (very very nearly) as my triple 24/36/48 with 14/28 on the back. The big advantage is that on the big ring of 40 I have almost the same range as the middle and outer rings combined on the triple but sequentially. So I only use the little ring when I am going to be in the small gears for a while and will need lower than 40 by 28.

Range of a front mech may be a problem. I use a Campag triple mech with Ergo levers which works just fine but Shimano might not like it because Shimano index the front so you need all the ramps etc to help changing. Shimano might also present another problem, especially if using an MTB front mech. The cage is a bit long and when it is set correctly for the chainring you might find that it fouls the chainstay or gear cable if it runs along the top of the chainstay.

Try it with your present chainset (which is what I have done0 and then you might consider buying a new chainset which is designed as an alpine double. SRAM do such chainsets for the MTB market. Because it is a "new idea" they might be a bit expensive at present but the price will come down.

If you're going to line up the 40t ring with the middle of the cassette, and use that chainring with all the rear sprockets, it might be a good idea to use a friction shifter to control the front mech. That way you could trim the front mech really effectively.

Thanks for the picture - thats exactly what I was thinking. RE the shifters; I already use friction barends for all the gears so trimming the front mech should not be a problem.

If I stay with the current triple crankset and modify it will I have to change the BB axel length?

Also would a road double mech work ok (it would be on friction - no indexing)?

So, a 24 inner and a 42 outer? How many miles of cycling would you have to do before the following kind of occurs to you: 'You know, if I just had something like a 34 in the middle of these two I would have a great spread of gears'. Answer: Not a lot of miles at all.

I understand that, I have always used a triple on my touring/communting bikes but I always feel that I never use all the options. I never 'max' out the gears i.e. 52x11 or 46x11 (This is what I currently have), on my fast road bike I would but only on long downhill decents or with the wind behind me.

Based on playing around with ratios I recon that 42x11 would suffice for me, fast enough - not overly fast but fast enough to be used way more often than 46x11.

Partner this with a 9 speed cassette, say 27x11, it should provide a wide enough range of gears that will all be used instead of only 3 or 4.

Perhaps if I move somewhere where the terrian is vey different or as I get older I would want to change the gearing, however right now I 'm curious to see if I can create a gearing that will work for me so that I use everything instead of just a few gears.

[reohn2]

I run 26-36-46 c/set with an 8sp 14/32(custom cogs) cassette.
For 90% of my riding I'm in either 36or46 rings,split around 40%,60% respectively,the 10% spent in the inner ring is the difference between riding and walking,walking is OK but not up a 20% climb pushing a bike .
There are odd times when I'm in 36x14or15 and think to myself,thats a nice gear,then I glance down at the chainline,which is crazy(the chainline not the glancing at it).
If I wanted a good chainline in that nice gear I'd need the 36t middle ring where the outer one is,so I'd need a BB axle 9mm longer(4.5mm either end)or similar.If I had a 40or42 instead of the 36 I wouldn't have a low enough gear for climbs that I can comfortably get up in 36x32.
Mostly I'm in 46x16/18/21/24 almost straight chain in 18/21,16and24 not bad at all.
That's my case for a triple.
If the Alpine double works for you use it or if you want to give it a try,try it.
Those are the reasons it doesn't work for me.

[Brucey]

but isn't 36/14 near as the same as..... 46/18?....

On the list of pluses for a triple you do have 'more gears with good chainlines', but alpine doubles do quite nicely for some folk.

Of all the arguments 'for' a double, the 'Q' one is probably most compelling for those who are fussy about that kind of thing.

cheers

[Valbrona]

And having the right gears isn't just about getting the right gear inches. There is also this thing called cadence. And, as Colin has pointed out, how well a set up shifts also matters.

[tatanab]

If I stay with the current triple crankset and modify it will I have to change the BB axel length?
Also would a road double mech work ok (it would be on friction - no indexing)?

I did not bother to change the bottom bracket, the chain line is fine.
Any mech should work if you are using friction. It might be better to find a mech designed for use with a compact double because the shape of the cage will more accurately follow you chainrings than one designed to follow the shape of a 53T.

This is my main touring machine so has done only 3000 miles or so since I built it 18 months ago. I have 3 other machines with 48/36/24 and 14-28 gearing which I would happily change to this quiche compact (the trendy name for these small ring setups) except it is not economic to do so. My top gear of 90 inches is quite enough for me, it is very close to the biggest gear I ever used when I was racing. I could pedal to about 35 mph but am likely to be freewheeling anything above 30 these days.

[reohn2]

If I stay with the current triple crankset and modify it will I have to change the BB axel length?
Also would a road double mech work ok (it would be on friction - no indexing)?

I did not bother to change the bottom bracket, the chain line is fine.
Any mech should work if you are using friction. It might be better to find a mech designed for use with a compact double because the shape of the cage will more accurately follow you chainrings than one designed to follow the shape of a 53T.............

If Vaya set a triple mech up as if there were an outer ring which is now a bash/chain guard,the two remaining rings(inner and middle) will change OK,without the need for going to the expense of another mech IMHO.

[tatanab]

If Vaya set a triple mech up as if there were an outer ring which is now a bash/chain guard,the two remaining rings(inner and middle) will change OK,without the need for going to the expense of another mech IMHO.

Note in my picture that the bash guard is the same size as the larger of the 2 chainrings (40T). Also I am using a Campag triple mech which works just fine. My suggestion was that the closer the radius of the front mech cage is to the radius of the larger chainring then the better the change is likely to be - else they would not sell front mechs to suit smaller diameter rings ---- ok, they probably would as a marketing ploy. I've not suggested that a change of mech is necessary, indeed I've demonstrated that I found no need, but I have suggested that it may help if there is a problem. I would always suggest that people take a low cost approach to try things out. This is what I did - I had the chainset, front mech and everything, all I had to find was a bashguard to suit. In my case it was a little difficult because I needed 135 PCD. For elegance I would suggest that the bashguard is the same size as the larger of the two rings.

As an aside - a possible benefit of using a quiche compact with a long arm rear mech is that jockey cage of the rear mech need not be pulled as far forward as it is on my triples (48/36/24) and the chain runs through the jockeys much more smoothly - same as on my triple set ups where everything seems smoother on the middle ring rather than the outer.

[reohn2]

Tatanab
My point was,nothing needs changing other than the middle ring size and a bashguard fitted,without even moving or disturbing anything.