Can I use all my gears?

[Auntie Helen]

I've just been reading 'Cyclecraft', the much-recommended book, in preparation for my training course to become a cycle instructor.

When reading it I came across again the thought that with derailleur gears you can't use all the gears as it's too much stretch for the chain - i.e. in biggest chainring you can't use smallest rear gear etc. I know this is true for normal bikes but is it also true for recumbents which have a much longer chain? I have a Trice with 27 gears.

 

[Andy in Sig]

I imagine that it is less the case because of the length of the chain but it won't eliminate the issue of overlapping gears i.e. if you are on an extreme one at the back and change at the front, you are likely to end up not where you want to be, if you see what I mean.

 

[Auntie Helen]

I already tend to do a gearchanging manoeuvre where when I change down on the front chainring I change up at the back at the same time - it tends to get me to a slightly lower gear than I was previously on, but not too different.

Of course my chain will undoubtedly fall off at an inopportune moment if I keep doing this but it adds a spice to the hill climbs that I do.

Oh, and last night I did my first reasonable distance ride in the dark (just 7 miles). Most was through Colchester on the main roads (I went down the high street at 10pm and got lots of yobs shouting at me - fortunately it was downhill so I was fast!) and then the last 3 miles are on the dark country lanes near my house. I had to reduce my speed a bit on the country lanes as I didn't feel I could see quite well enough ahead. A cat slinking through a hedge was a bit spooky! Still the 'big deal' of cycling in the dark is now dealt with - it was fine.

 

[Riding in Circles]

You should be able to set up chain length to cope with an 11-32 cassette and a 30-42-52 front triple without any chain crossover, as long as you have a long cage rear derailleur. You can then use all gears although at least 12 of them are duplicated. So a standard 27 speed road setup will only have 15-16 unique gears anyway.

 

[Auntie Helen]

If I'd known more about the gears when I bought the trike I might have had the Rohloff at the back - the opportunity to change down gear when stationary would be good with a lot of the town riding I do. Still the system works OK at the moment, I just realised t'other day I was cycling in the lowest gear on the biggest chainring (if that's how it's described technically) and wondered if it'd be doing the gearing any damage. Sounds like it should be OK. Thanks for all your answers!

 

[byegad]

On my Kettwiesel, range 15" to 88" and a fairly short rear mech I can and do use 8 out of 9 rear cassettes when on the small chainring, all 9 on the middle and 7 out of 9 on the big chainring.

On my QNT 15" to 104" it's all 9 on both of the smaller chainrings and 7 out of 9 on the big one.

Using both the front and back big rings together can be posible if the chain is long enough. I run a slightly shorter chain as I find I use the small ring front and the higher/faster gears back quiet often, however, this does mean that an inadvertent change to big/big could damage the rear mech'.

As I'm fairly confident I won't do that I chose to run that risk.

If you have a look at the rear mech when your trike is on big/big (be gentle getting it there, the best way would be to have someone hold the back wheel off the ground while you turn the pedals by hand and change the gears). If the rear mech is straight forward then, with your weight on the trike and suspension movement from the road you could over stretch the mech.

Also try small/small while your at it and see how the mech tucks back to keep the chain taut and the chain rubs at the closest point. If the chain goes to the side at that point, say due to road vibration you will again strain the mech (this time in a twisting motion).

Once you know what it looks like at the back you'll soon remember to avoid potentially poor combinations.

When it is time to change the chain you can decide if you'd rather be safe in big/big by adding a link or two, or safe in small/small by shortening by the same amount.

A long chain is the best for a new rider as it more easily causes damage to have a shortish chain and go big/big by accident, you can get away with small/small more often as it takes an accidental selection AND the chain to skip off a pulley in the mech.

Finally, much off what is said re crossover is about the amount the chian is moved across between the front and back rings. Recumbents have longer chain runs (my QNT use two and two thirds standard chains) so the side to side bend caused by running at the extremes is less of an issue for us but the capacity of the rear mech to handle the chain tension is still the limiting factor.

Hope that helps, pm me if you want any more details. Geoff

 

[Auntie Helen]

Hi Geoff,

Thanks for this. We've set my bike up for big/big as I use that more than small/small (in fact I've only used the lowest chainring once in the last couple of months). From what I can tell (my husband did it) the chain is fine. I do find, when using the small chainring, I can feel a certain amount of 'give' as the chain is so loose, I suppose. However I don't use big/big too often now, I'm learning to change down to the middle chainring earlier as that one gives a quieter ride anyway. I've learned that my cadence is a bit low so am trying to improve that and changing down gears earlier is part of it.

Sounds like I'm unlikely to be doing anything seriously wrong with the gears at the moment. It's yet another example of something in cyclecraft that isn't such an issue on trikes - there were loads of things like that, such as braking with the back brake first (so you don't go over the handlebars) and many other safety items. Makes me very glad and safe to be on a recumbent trike!

 

[byegad]

Wait untill you get the back wheel off the ground under heavy braking! The trike tries to spin when you do and a bit of modulation is needed on the brakes to keep it straight!

 

[Auntie Helen]

Wait untill you get the back wheel off the ground under heavy braking! The trike tries to spin when you do and a bit of modulation is needed on the brakes to keep it straight!

Think I might be too heavy to do that! Haven't had a sniff of anything like that happening yet. I've never lifted a wheel either although my husband, who has the QNT admittedly, seems to do it fairly regularly (although he's always under control and usually just doing it to be juvenile, I think!)

 

[Riding in Circles]

If you want an option while stationary you could consider a Schlumpf High Speed Drive, it will give you a wider gear range with more usable gears and the option of being able to go from high to low ratio in the front while stood still, costs a lot less than a Rohloff.

 

[Auntie Helen]

Looks interesting, have you used one of these?

 

[Riding in Circles]

Looks interesting, have you used one of these?

Yes, I have just fitted one to a customers trike, I like them a lot, I have one on one of the demo's as well.

 

[byegad]

The theoretical downside is the extra drag in the non direct drive gear (probably not too much of a real world problem) and the big step 235% IIRC which makes for a long change as you come up form the low drive as you change the rear cassette from one end to the other! (This one has put me off buying one but I did come close this time last year.)
Also there is it the HS drive that has a fixed chainring size? I know one of the Schlumpfs has this.

 

[squeaker]

Personally I'd always set up a 3 x 9 so that it had sufficient chain length (under all suspension movement) for the big-big combination, even at the expense of not being able to use all the small-small combinations due to the rear mech having too little capacity (but the standard Trice setup is fine).
As most RWD 'bents use a power idler (or have a very long chain) there is no issue from high chain angles (unlike the relatively short chain run on a DF) when using small-big or big-small combinations.
I've been running a dual drive on my Grasshopper, which does give you a modest ratio drop when static if you get caught out (e.g. panic stop from high speed), but it's less of an issue on a trike as you can start in a high gear, IME!

 

[arallsopp]

I'm on a dual drive with the SMGTe too. Seems the perfect combination, with an 8 speed derailleur and a 3 speed hub gear. Took me a while to remember to shift down on the cassette before the hub, but I'm there now.

I find this way works best as I rarely need to change up a gear unexpectedly, but quite often find a need to halve my ratio without warning when a dog / cat / pedestrian / car / hill jumps into my path.

Nothing worse than grinding up a hill going clack-clack-brggr-clack at the back, whilst the derailleur battles to change under load. On my first day out, I got a bit wobbly (admittedly not an issue on a trike) and had to put a foot down. Left myself in bottom on the hub and top on the cassette, so had to slog away at a very poor pace, and covering far more lateral than forward distance. On a DF, its easily resolved. Pick up the rear wheel, push the pedal round a couple of times, and change gear. Ever tried to simultaneously lift the rear wheel and pedal a 'bent without the aid of strong brakes and a hill? No fun