Author Topic: Is this an unusual gearing for a touring recumbent? (Read 4799 times)

TPMB12 · « **on:** 03 April, 2022, 04:03:44 pm »

Got local bike guy to sort gearing / drivetrain out. Everything but derailleur got replaced including jockey wheels. Works fine but left it to him to source the parts. He swapped out gears for gears I believe so it is now same as before but newer.

Just been for another ride with hills, some steep, undulating the rest. Struggled so checked the gears out. 52/42/30t up front and an 11-32t 9 speed cassette. My road bike is 50/34 with 12-32t and I find it easier than my recumbent by some margin. Obviously I need recumbent legs but it seems more than that. Is 52 42 30 an unusual chainring option? Not good for touring but what would it be good for? Road bike upright only I guess.

The other question is what's needed to be changed for touring? Can I change to 11 or 12t to 36 cassette as a quick improvement? Might be no good for week after next but summer tour will need it. Hopefully Ardennes which has some hills enough to trouble me fully loaded potentially with dog trailer too. Or should I go to something like 48 36 30t chainring? Which would need least fettling to make work? Which would give the biggest low gear improvement. Currently 23.3 to 117.6 gear inches. From what I have read 18 gear inches is best low end with high end not as important.

I think 48 36 30 and 12 to 36 cassette might be best I can get at 20.7 to 99.5 gear inches. Or something else? Would 36t cassette be too much for old deore derailleur? Doubt it's long cage or shadow or whatever is normally needed for big cassette option.

cycleman · « **Reply #1 on:** 03 April, 2022, 06:37:38 pm »

I would fit a 42 32 22 and 11 34 if 36 won't fit bear in mind that you can't stand on the pedals on a recumbent so spinning upwards is obligatory

Mr Larrington · « **Reply #2 on:** 03 April, 2022, 06:52:19 pm »

Depends on what chainset you've got - sounds like a 130/74 road triple to this Unit, so the smallest inner you can fit is a 24 and the smallest middle a 38. Any smaller will require swapping the chainset for a Perfectly Good Gentleman’s Mountain Bicycle version.

Tigerbiten · « **Reply #3 on:** 03 April, 2022, 07:20:18 pm »

Ok, long post on how I setup gearing.
Start with an 12-14-16-18-21-24-28-32-36 9 block.
The average step between the gears is 15%, between 2 gears is 33% and between 3 is 50%.
So starting at the front.
30 x1.33 = 40 x1.33 =53, this gives you a 30/40/53 road triple with 2 gears steps between each ring.
Your 30/42/52 is similar but the middle ring is slightly bigger giving you slight higher speeds in that ring.
Now 34 x1.5 =51, round the 51 down to 50 and you have a compact double with 3 gear steps between each ring.
Now if you want to maximize range the 24 x1.5 =36 x1.33 =48 giving you a 24/36/48 MTB triple with 3 gear steps between the inner and middle ring and 2 between the middle and outer.
You can start off with either a 26t or 22t inner and adjust the other rings to match if you want to fine tune the resulting gears up or down a bit.
Plus a 24 tooth difference is around the capacity limit of a front derailleur.
Setting up the front rings at either X1.33 or 1.5 does make shifting between the rings very predicable.
Shift a ring early for a hill and then 2 or 3 sprockets as needed and you're back in the gear you started with, just one chainring different.
Now the capacity of a long cage rear derailleur is around 48 teeth.
That out 24 for the front for the MTB triple, that leaves 24 for the back.
Now the 12-36 9 block has that 24 tooth if you're going for maximum gear range.
The other is to split the rear cassette into two zones.
Above around 15mph, wind resistance ramps up badly and it gets harder to spin up each gear enough to make
shifting up worth while.
So you switch from a 2 tooth difference to a 1 tooth difference for the 4 smallest sprockets, but you do loose the two biggest sprockets.
That gives you an 11-12-13-14-16-18-21-24-28 9 block. That's better for ticking along at around 15 mph, but you do loose the bottom two gear of the 12-36 setup.
My thoughts on other 9 blocks are not good.
An 11-13 step is to big, you're better starting 12-14, plus you tend to get a nasty step going from odd sized sprockets to even sized.
A block starting 11-12-14, a single narrow step is not worth it as it's hard to spin the 12-14 step up to speed, again the 11-12-13-14 is better.

Luck ............

TPMB12 · « **Reply #4 on:** 04 April, 2022, 06:49:09 am »

It does look as though the middle ring doesn't quite suit to me.

cycleman · « **Reply #5 on:** 04 April, 2022, 08:24:07 am »

Tigerbiten , can you repeat that using sensible gear inches please

Tigerbiten · « **Reply #6 on:** 04 April, 2022, 10:49:09 am »

The trouble is "sensible gear inches" needs to take into account your cadence.
If you've a natural slow cadence, around 60-70 rpm, then you may find a top gear of around 120" sensible as you'll spinout at around 30 mph.
Where as if you've a fast cadence, 80-90 rpm, then a top gear of only around 100" would be more sensible.

I'd start from my basics for touring gears.
The largest chainring only needs to be 4x bigger than the smallest sprocket and the largest sprocket wants to be 4 teeth bigger than the smallest sprocket.
That gives you a gear range of roughly 25"-110"or a 4.5x range.
As it's fairly easy nowadays to get a 5.5x-6x gear range then you can tweak the above range to match you're riding style.
Starting from something like a 24-36-48 triple to maximize your gear range.
If you like to go fast then you can bias the gears high with an 11-28 9 block.
That gives roughly 23"-118" but with a lot of close gears above 70" to help you to get up to speed.
If you've weak legs then you can bias the gears low with a 12-36 9 block to maximize your range.
This gives you a gear range of 18"-108", not many high gears but some super low gears for easy/slow hill climbing if you can keep your balance on a bike.
You can further tweak them to match your style by altering the chainring sizes a little.
If you've a slow cadence then a 26-38-50 triple may work better for you and if fast then maybe a 22-34-46 triple.
You can further tweak it with different cassettes but these two are probably the two extremes (fast vs slow) you should start from.

Luck .............

TPMB12 · « **Reply #7 on:** 04 April, 2022, 04:57:51 pm »

Don't know what my cadence is but years ago I tried the 80 to 90 spinning but found it more tiring than 70 to 80 or less uphill. That's upright and I've slowed down and switched to recumbent again. All I know was a short ride Sunday had me on lowest gear and spinning at 3 to 6mph depending on gradient. To be fair I wasn't loaded but was towing a 2 wheeled dog trailer weighing 12kg with a 10kg dog in it. The hills aren't really that steep but felt it. My upright I'd be cruising up them nicely 50 34 and 11 to 32 cassette on 700x38 m pluses. My bent is on racer like schwalbes at 28mm in 406 and 559.

I think low is better for me when loaded. Especially with dog trailer. I think I'm on 23 gear inches. A lot of touring sites say 18" is the ideal low gear when loaded. That's on upright touring. Does that really change with recumbents?

What's with short cranks? I've got 175 on upright and recumbent bikes. I think I can't drop crank size without affecting bike fit. I'm at limit with the boom.

Blodwyn Pig · « **Reply #8 on:** 04 April, 2022, 05:25:37 pm »

if you're quick.......

https://forum.cyclinguk.org/viewtopic.php?p=1684969#p1684969

Kim · « **Reply #9 on:** 04 April, 2022, 06:02:48 pm »

Quote from: TPMB12 on 04 April, 2022, 04:57:51 pm

I think low is better for me when loaded. Especially with dog trailer. I think I'm on 23 gear inches. A lot of touring sites say 18" is the ideal low gear when loaded. That's on upright touring. Does that really change with recumbents?

I think it's just that higher cadence makes it slightly easier to balance a recumbent bike when moving slowly, to compensate for not being able to shift your body weight.

That and recumbents are nearly always annoying to get off and push, so you want to keep riding below walking speed if necessary. Hence gearing down to the limit of traction on trikes.

Quote

What's with short cranks? I've got 175 on upright and recumbent bikes. I think I can't drop crank size without affecting bike fit. I'm at limit with the boom.

Long cranks are for tall people. Anyone can get used to short cranks, as long as they're not allergic to spinning.

Short cranks fit more easily inside fairings.

Short cranks raise the gain ratio, so you need lower gears to compensate.

If you're happy with 175, I don't see a reason to change, unless you have a fairing that doesn't fit.

cycleman · « **Reply #10 on:** 04 April, 2022, 08:21:15 pm »

The 10 speed system I fitting to the tricon gr will be 44-32-22 combined with a 11-46 cassette. This will give me a 13" bottom gear. Apparently its possible to balance a mountain bike using the bottom gear

. I have weak legs and my knees hurt when push to hard so the longer I spin uphill the better

.
Thanks for the inches tigerbiten

Lightning Phil · « **Reply #11 on:** 04 April, 2022, 10:37:36 pm »

I run 19” to 113” on my recumbent. My turbo indicates my cadence sits between 85-95, a double chevron hill will reduce that!

Tigerbiten · « **Reply #12 on:** 05 April, 2022, 05:33:38 am »

The easy way to roughly work out your natural cadence is .......
Find a nice flat/slightly downhill piece of road and hit 15 mph on it with a cadence you feel could keep up for an hour or two.
Record what gear you're in and workout it's gear inches.
Starting from:- A 100" gear spun at 100 rpm = 30 mph.
Then at 15 mph:- gear inches/100 X cadence/100 = 0.5
So at 15 mph:- 100" gear = 50 rpm, 80"= 60, 70"=70rpm, 60"=80, 50"=100.
You can use other speeds but 15 mph make the maths easy.

Mines now in the 70-80 rpm range, drops down to around 50-60 in low power mode on hills and I'll spinout at just over 90 at my efficiency tanks at that cadence.

Luck ...........

ElyDave · « **Reply #13 on:** 05 April, 2022, 06:36:13 am »

Could you repeat all that in km and m development please?

(click to show/hide)

TPMB12 · « **Reply #14 on:** 05 April, 2022, 07:18:37 am »

I tend to think I'll stop pedalling when I reach anywhere close to 100 cadence. I'm no longer bothered by speed. It doesn't bother me and I don't bother with it. Besides above 15mph I'm likely to be braking back to below 15 with a dog trailer.

My old child trailer from burley have a 15mph top safe speed. Hard to keep back 5 years but assuming the dog trailers the same top speed I find it easier now. Keeping below 15mph ish. Very easy to go from 4mph when going over the top to 16mph down the other side round here. It's the 3 to 6mph bottom gear times I'm struggling with right now.

I find a hilly ride gets my quads on the upright but quads and calf muscles on the bent. It's the same basic motion just tilted to a different angle. Is it simply that tilt up that changes the muscle demands? Off topic, sorry.

Gears are simple to the experienced bike tweaker but to someone who's experienced cycling but simply replaced like for like on his bikes this idea of choosing your gears to meet your cycling style or demands is difficult. How do you find out what you really need when your experience is limited? You can't without potentially expense being applied. In my case parts and labour from bike guy I use.

Hate gear tweaking. Can do it but takes me so long and I mess up on the way. No front derailleur in Scottish Highlands Islands with single wheel trailer and rear pannier overloaded! Don't tweak mid tour without your full tools when it's only a little catch of the chain in one gear. Lesson learnt!

Anyway I've just spent £100 on marathons for the lads bike and pluses on my bent for a holiday over Easter my tyres were flat in centre tread and his had cheap kenda tyres that puncture for fun. So I'm not changing my gears. Spent too much for this holiday and it's less than a week away. Too late. So I'm stuck with 23.3 gear inches on a fully loaded bent possibly with a dog trailer too, unless the other half takes the dog. She's got mtb with I think 16 gear inches or less. She can spin out going backwards!

Lightning Phil · « **Reply #15 on:** 05 April, 2022, 08:18:43 am »

Regards calf muscles do you use clipless? If you move the cleats back it reduces strain on the calf muscles and Achilles.

Tigerbiten · « **Reply #16 on:** 05 April, 2022, 09:03:31 am »

Learning about gears and how you can tweak them to make cycling easier is difficult to learn.
As you said, you tend to end up replacing like for like because it's the only thing you know.
Write down what you like and dislike about your gears.
Is the top gear to high/low, is the first gear to high/low, is there a nasty big step which takes more effort as you go up the gears, etc, etc.
Then if you know what you like/don't like, the next time you alter your gears go into a gear calculator and play around a bit.
That's what I did when I upgraded my first bent trike.
I knew what I wanted (more range) when I upgraded, played around in a calculator until I found something that could possibly work (twin hub gears), asked if it that combo was possible when I upgraded to a new trike (it was), paid extra (mega ££) for the upgrade as it's very non-standard.
Then spent another couple of years tweaking it more to get a finalized version, I've now 3x the gear range of my first trike.

My understanding of "bent" legs is ......
The more reclined you are on a bent, bigger knee-hip-shoulder angle, the less power you generate from your gluts so you need more from your quads for the same power. Hence your quads fatigue quicker on a bent vs an upwrong.
The result of this is your max sustained power is lower on a bent so you will climb hills slower.
But your also more aerodynamic so you'll descend quicker.
As for your calves, again the angles are slightly different. I'd try moving your cleats slightly further back from normal and see if it solves that problem.

TPMB12 · « **Reply #17 on:** 05 April, 2022, 03:58:25 pm »

I'm wondering if a mountain schlumf drive might be a good idea for steep uphills?

For me 23.3 is not low enough but I can spin out easily on a 52/11 gear. 122 on hills but I simply freewheel them anyway.

cycleman · « **Reply #18 on:** 05 April, 2022, 06:55:51 pm »

I thought that I had solved my low gear woes but the rear 10 derailleur and the 10 shifter are apparently not currently available

. My shop may resort to megaranging my current cassette by Engineering a 40 sprocket of the old sunrace cassette. There is even a chance it'll work

cycleman · « **Reply #19 on:** 06 April, 2022, 07:37:54 pm »

The shop swapped the 36 cog for the 40 from the sunrace cassette and it's working so I have a 15 inch lowest gear. I will wait for the parts to come in for the 10 speed system as I like the idea of a 13 inch bottom gear

Tigerbiten · « **Reply #20 on:** 07 April, 2022, 12:11:59 am »

I run a Schlumpf drive on my bent trike.
It's expensive but ideal if you want a "mega" gear range.
For example:- A Rohloff is really a 7 speed hub with an internal x2.45 step down, add the x2.5step up of a HSD for 21 unique gears.
If you are going to fit a Schlumpf drive, you need to decide if you're going to run single or twin chainring.
A single chainring is simple as you don't need a chain tensioner, but you will need to shift 6-7 gear when you change the drives gear range.
Twin chainrings will need a chain tensioner, but you can split the 6-7 shift into two operations. Plus having the second chainring lets you further tweak the gears, either more range or closer gears.
I went for more range.
I now wouldn't be without my 9.4" first gear or my 178" top gear on my bent trike.

Luck .........

TPMB12 · « **Reply #21 on:** 07 April, 2022, 07:23:03 am »

Which model did you get? Sounds like the mountain drive.

How much did it cost BTW? I suspect out of my price range. Just spent £100 on tyres for my bent and kids bike. It got a comment about spending too much on my bent, which is an indulgence possibly extravagant waste of money, apparently. That's from someone who's done more cycling than I have.

Blodwyn Pig · « **Reply #22 on:** 07 April, 2022, 11:13:13 am »

Quote from: Tigerbiten on 05 April, 2022, 05:33:38 am

The easy way to roughly work out your natural cadence is .......
Find a nice flat/slightly downhill piece of road and hit 15 mph on it with a cadence you feel could keep up for an hour or two.
Record what gear you're in and workout it's gear inches.
Starting from:- A 100" gear spun at 100 rpm = 30 mph.
Then at 15 mph:- gear inches/100 X cadence/100 = 0.5
So at 15 mph:- 100" gear = 50 rpm, 80"= 60, 70"=70rpm, 60"=80, 50"=100.
You can use other speeds but 15 mph make the maths easy.

Mines now in the 70-80 rpm range, drops down to around 50-60 in low power mode on hills and I'll spinout at just over 90 at my efficiency tanks at that cadence.

Luck ...........

Easiest way to work out cadence is......flat road, (no tailwind), pedal at your natural speed, look at watch, when second hand reaches 12 o'clock count the number f times your right (or left?) pedal reaches bottom of stroke, in 15 secs, ie 18, 20, 22 . Then just times x4. Do it few times just to check. mines approx 78 - 82 ish when cruisin' on the GTE that is called Grunhilda.!. But slightly more when I'm trying to go F A S T.

TPMB12 · « **Reply #23 on:** 08 April, 2022, 06:39:02 am »

The GT doesn't understand what fast is. Try as I might it doesn't quite get there! It's not me but the bike, honest!

Tigerbiten · « **Reply #24 on:** 08 April, 2022, 08:02:05 am »

Fast is easy .....

I've done enough hills to know if I double the angle down then the steeper slope adds roughly 10mph to my speed.
So starting at ~20mph on a 2% downslope then by the time I reach a 16% downslope then 50mph is achievable.
The hard part is getting back to the top to do it again.

Weeeeee ...........