Post by: Beardy on 06 October, 2019, 03:19:29 pm
So, what gear range have you got on your ‘bent. How high and low do you go in ‘normal’ use.
And a bonus question. Is anyone using oval rings?
Post by: Blade on 06 October, 2019, 04:13:14 pm
Lowest ratio is 11.2 inches and highest is 114 inches. When using the lowest ratio, I'm barely moving and if on a two wheeled recumbent would be unable to balance.
I mainly leave the hub gear in the central position giving direct drive.
Cruising ratio on the flat, I'm usually somewhere in the 60's for gear inches.
Post by: network.ned on 06 October, 2019, 04:26:52 pm
There are now some ridiculous MTB cassettes out there now which may help. 10 speed with 11-46 range is now easy to get hold of which might mean less overlap and fewer chain rings. Obviously the downside of these is that the gear to gear steps can be quite large.
My upwrong commuter is 700c and ranges 28-119"
I'm currently toying with the idea of 20" wheels, something like 75-44 chain rings and an 11-42 cassette which gives a range of 19-125" in steps of between 6-10". The other thing I'm toying with is a Capreo rear wheel with a 9t sprocket which would allow slightly smaller chainrings for a decent top gear.
Looking for a PDQ frame to restart my recumbent collection!
Post by: network.ned on 06 October, 2019, 04:28:50 pm
My trike has a Sram 3 speed hub Dual drive fitted and has a nine speed cassette.
@Blade, what size drive wheel are you running?
Looking for a PDQ frame to restart my recumbent collection!
Post by: lmm on 06 October, 2019, 04:30:53 pm
At the low end I definitely run out of balance before I run out of gears. Long climbs of 10% or less are no problem (I enjoyed chugging past the walking Rapha gang on Ditchling for this year's London-Brighton - especially those who'd whizzed past me at the start of the climb), steeper than that and it gets a bit dicey (but bear in mind I'm very overweight).
At the high end I occasionally wish for another gear (particularly unladen) but I'm sure if I had one I'd use it inappropriately. Top gear is a comfortable cruising speed on the flat which is what I want really - I ride distance rather than speed. If I were doing time trials or racing then I'd want faster gears, which I guess would have to mean a less standard size or indeed something custom, unless someone's selling recumbents with full size drive wheels.
Post by: Tigerbiten on 06 October, 2019, 04:34:20 pm
The easiest way to get a big range on a 20" wheel is to add an SA CS-RF3 hub to the mix.
This will give you the equivalent of 5 chainrings, 3 standard plus an overdrive & granny ring.
Using a standard 53-39-30 road triple with a 11-28 9 speed which gives you a 15"-120" range.
Plus it gives you the ability to drop a range after an emergency stop.
I use a 55-38 double on a Schlumpf HSD and a 21 sprocket on a Rohloff hub which gives me a total range of 9.4" - 179.4" on my bent trike.
My normal range is around 20"-120", the rest are use as an overdrive and granny range.
I cannot use oval rings on a HSD due to the overdrive mode spinning the chainring faster than the crank.
Luck ......... :D
Edit:- The Dual Drive is no longer made, the SA CS-RF3 hub is the direct replacement.
Post by: Blade on 06 October, 2019, 04:43:14 pm
My trike has 20 inch wheels.My trike has a Sram 3 speed hub Dual drive fitted and has a nine speed cassette.
@Blade, what size drive wheel are you running?
Looking for a PDQ frame to restart my recumbent collection!
Post by: Kim on 06 October, 2019, 10:31:59 pm
1.4-9.3 (17.6"-113") on the Streetmachine. I'll live in the middle ring for normal un-loaded riding. Big ring for fast descents and to get a half-step ratio for the flatlands. Granny ring only normally needed when loaded.
1.4-9.3 (17.1"-113") on the Baron. Big ring gets a lot of use. Granny ring only really there as a bailout gear to keep the cadence up on steep climbs. Have a race wheel that sacrifices some bottom end for closer ratios.
1.3-9.4 (16.1"-113") on barakta's ICE trike (in electric mode). I never use the granny ring with the motor. Don't think barakta does much, either. Big ring could be a bit bigger, but MTB crankset.
1.3-8.6 (15.6"-102.4") on barakta's ICE trike (in non-electric mode). Top end is lacking for fast descents, but about right for barakta. Bottom end lower than is reasonable on a bike.
Post by: Phil W on 07 October, 2019, 07:25:44 am
Post by: Tigerbiten on 07 October, 2019, 07:52:50 am
I'm currently toying with the idea of 20" wheels, something like 75-44 chainrings and an 11-42 cassette which gives a range of 19-125" in steps of between 6-10". The other thing I'm toying with is a Capreo rear wheel with a 9t sprocket which would allow slightly smaller chainrings for a decent top gear.I looked into this when I upgraded my trike.
That probably won't work.
I ran a 22-36-48 triple and a 9-32 Capreo hub 20" rear wheel (12.5"-100") on my first bent trike and maxed the range of both derailleurs out.
Max range of a rear derailleur is just under 50 teeth and the front is around 26 teeth.
42-11 is 31 teeth.
That leaves only around 20 teeth maximum for the range at the front.
You cannot fit a non standard longer rear derailleur for a greater total range because it will hit the ground with a 20" wheel.
You can mod a front derailleur for a greater range, but you'd still be limited by the back.
The Capreo hub is only a 9 speed and the smallest 4 sprockets are fixed, that only gives you 5 sprockets to work with.
With a Rohloff on a 20" wheel, you'd need a 13 sprocket and a 38-56 double for a 15"-118" range.
A 13 sprocket and a 38-50-65 triple is just doable for a 15"-137" range.
Luck ......... ;D
Post by: ElyDave on 07 October, 2019, 10:57:48 am
M5 had 50/34 up front and 11sp 11-40 MTB casette on the back. All 22 gears usable.
Both with 700c wheels and 28mm Conti GP 4 Seasons
Post by: Mr Larrington on 07 October, 2019, 01:55:32 pm
Cosimo the Stealth Baron (26") has 12-25 9-speed and 53-39 double, but has never ventured onto a real road. Top gear only ever got used on the hill that led onto the back straight at Eastway.
Speedmachine (26") has 11-32 9-speed and, IIRC, 48-36-20 triple (TA Zephyr chainset).
Trice XXL (20") has 11-32 9-speed and 52-38(?)-24 triple (Campag road triple with titchy inner ring that crept of of a box in the Sheds).
I've never felt the need for Monster Gears on an unfaired road-going machine. If you're spinning out then sit back, relax and enjoy the view.
Post by: Kim on 07 October, 2019, 02:09:23 pm
Cosimo the Stealth Baron (26") has 12-25 9-speed and 53-39 double, but has never ventured onto a real road. Top gear only ever got used on the hill that led onto the back straight at Eastway.
It's shocking how different my use of gears on the track is compared to even flat roads. Nevertheless, as a mere human who rides like a GURL without the aid of fairings, a 50T chainring is perfectly sufficient.
Quote
I've never felt the need for Monster Gears on an unfaired road-going machine. If you're spinning out then sit back, relax and enjoy the view.
The only reason the big ring on my Streetmachine is as big as it is is because with the right combination of shifts it gives half-step ratios that come in handy on the odd occasion I venture into the flatlands. My R17 descending career never really recovered from that front wheel blowout I had a couple of years ago, and I've generally found that once you're past about 35mph it's more useful to shuffle down in the seat and tuck your legs and elbows in than it is to flap around turning the pedals. (Also, while it's true that aerodynamics trumps linear power gains at high speed, aerodynamics is itself trumped by TEH FEAR, which probably goes up with the natural logarithm of how much it's going to hurt, or something.)
Post by: lmm on 07 October, 2019, 04:35:57 pm
Post by: ElyDave on 07 October, 2019, 05:29:25 pm
Could have used the big ring in parts, but no real point, I was just relaxing. Still came home second only 5-10 mins behing the guy who left the halfway control ahead of me, both of us having hit the control ahead of time.
Post by: network.ned on 07 October, 2019, 07:05:44 pm
That probably won't work.
I ran a 22-36-48 triple and a 9-32 Capreo hub 20" rear wheel (12.5"-100") on my first bent trike and maxed the range of both derailleurs out.
Max range of a rear derailleur is just under 50 teeth and the front is around 26 teeth.
42-11 is 31 teeth.
That leaves only around 20 teeth maximum for the range at the front.
You cannot fit a non standard longer rear derailleur for a greater total range because it will hit the ground with a 20" wheel.
I'd neglected to consider the mech dangle factor! Thank you.
Given your experience it sounds like I might be needing to look at an 11-32 with sensible sized chain rings and an education in either chilling out or high cadence
. I guess as a start point, standard chainsets should be relatively cheap to get going and I can then faff with chain ring sizes later.Looking for a PDQ frame to restart my recumbent collection!
Post by: Tigerbiten on 07 October, 2019, 10:52:16 pm
Given your experience it sounds like I might be needing to look at an 11-32 with sensible sized chain rings and an education in either chilling out or high cadenceDo the maths......
chainring / sprocket x wheel = gear, gear x sprocket / wheel = chainring, chainring / gear x wheel = sprocket.
If 100" top gear, 20" first gear, 11t small sprocket and a 40-406 wheel is ~18.5"-19" diameter.
Then 100 x 11 / 18.75 = ~58 teeth for large chainring.
You should just be able to get away with a 12t drop per chainring.
So a 34/46/58 triple to start with.
And 34 / 20 x 18.75 = ~32 teeth for large sprocket.
Total tooth difference for the chain is 45 teeth.
You'll be pushing the limits of both derailleurs so no guarantees.
But it's probably doable for a 20"-100" range ....... :thumbsup:
Going 36/48/58 and 11-34 is probably better idea.
The 36/48/58 and a 9-32 Capreo hub lifts top gear to ~120".
But you can fine tune it from here.
Luck ........... :D
Post by: Socks on 08 October, 2019, 12:45:38 pm
I might try smaller chainrings, I rarely use top gears and a lower one would help on steep hills if I can maintain enough speed to balance.
Post by: Kim on 08 October, 2019, 12:50:01 pm
Interesting too see how low some of the gear ratios go even on a two wheel recumbent.
As usual, nobody's talking about crank length. Spinning helps you balance a two-wheeler. Shorter cranks make spinning easier. Shorter cranks raise the gain ratio, so require lower gearing to compensate.
My 17.6" gear feels like a 20" gear would with 170mm cranks.
Post by: Mr Larrington on 08 October, 2019, 01:18:43 pm
Post by: Kim on 08 October, 2019, 01:26:30 pm
Remember that if you take care to avoid trying to use silly small-small or large-large combinations you can exceed the manufacturers' stated derailleur capacity by a fair chunk. Get it wrong, mind, and you and your chain tool will spend a long time at the roadside, swearing.
Depending on the chain run, the chain going completely slack in small:small may not be a problem. On an ICE trike, for example, the weight of the chain in its tube acts as a tensioner, and everything still works as long as you don't backpedal too much. (This is occasionally useful, because small:small raises the dreailleur of a small-rear-wheeled cycle out of the recently-mown grass, while maintaining an appropriate gear for off-road riding.)
I always set things up so that large:large works well enough that it doesn't jam. You are going to crash-downshift to the big sprocket at some point without remembering what chainring you're in due to traffic shenanigans, and it's best to be able to recover from that with nothing worse than a bit of derailleur-fu.
Post by: Tigerbiten on 08 October, 2019, 01:54:47 pm
But Schlumpf only make 170mm Kick plates for their drives.
So I'm stuck at that length.
As for silly high gears, I like them because they match with my riding style.
My natural cadence is around the 70-80 rpm range and if I go over 90 rpm then my efficiency takes a big hit.
I also don't like to freewheel downhill if I can avoid it.
So having a 179" top gear means I can have "fun" pedalling slowly downhill at 40 mph ...... :P
At that type of speed I'm not putting a lot of energy into turning the pedals.
It's more about shifting any lactic acid out of the leg muscles while keeping them warm.
YMMV ........ ;D
Post by: Arellcat on 08 October, 2019, 09:29:55 pm
1.7–8.3 (22.7"–111.6") in my Quest velo with 170mm cranks. Top gear is 52-12 (from my impossible-to-buy Shimano 12-34 cassette), and isn't high enough. Riding the mean streets into and out of Edinburgh, I use almost every single ratio at one time or another.
1.6–8.7 (22.4"–120.0") with my Lightning P-38 and 175mm cranks. Same cassette as my Quest; the small and middle chainrings get a lot of use, the big ring not so much.
Post by: McWheels on 12 October, 2019, 12:08:16 pm
Post by: mzjo on 12 October, 2019, 09:26:12 pm
https://www.dutchbikebits.com/recumbent-velomobile-parts/alligt-chainrings
Post by: Tigerbiten on 12 October, 2019, 10:42:38 pm
If anyone needs chainrings bigger than normal and has difficulty finding them this might be useful. I believe they supply a few racers.Spa Cycles do every size TA chainrings in both 130mm and 110mm up to 60 teeth.
https://www.dutchbikebits.com/recumbent-velomobile-parts/alligt-chainrings
Thats where I go for a 55t chainring.
The only trouble with that size is it's not ramped and pinned.
But I don't think any are over 53t or I've not found one above that size.
But good shout if you need bigger ....... :thumbsup:
Post by: Nightmare-1 on 28 October, 2019, 12:25:45 am
52/42/30 & 11-32 on the XL 170mm cranks
48/36/24 & 9-32 Capreo on the Vortex fs 170mm cranks (this will change to 53/39/26 152mm cranks soon).
If you are looking for shorter cranks to help with higher cadence/spinning out, ICE sell 152mm cranks.
The Lower foot speed of the 152mm cranks compared to 165-175mm for a given cadence , means you can get higher cadence rpm before spinning out.
The downside of shorter cranks is "It's harder to pedal uphill" (with the same gearing).
Post by: NUKe on 28 October, 2019, 03:51:20 pm
48 tooth chain ring SRAM 850 11 32 sprocket and give me 20.6 to 111 gear inches.
Way more range than I need for Suffolk and Norfolk.
Post by: Phil W on 30 December, 2019, 09:37:36 pm
175mm cranks as that what I have always run on the mtn bike the cranks were taken off.
Spend most of time in big or middle at front. Middle chain ring up to about 10-12% gradient unless tired.
Post by: Blodwyn Pig on 11 May, 2020, 08:00:35 am
My newly acquired streetmachine has 170mm cranks. 52,42,30, and a 9 speed block,11-34. I find big/ big and very useful gear, and do seem to spend a lot of time on the larger ring. I'm trying to spin, but 80-90 is about max for me, unless in short bursts. Not tried a BIG hill yet or the granny. Only 400km in so far. Was reading about shorter cranks and thinking about 160mm, but I'm 6'2" and have long ( big) legs, so spinning fast is not a natural for me. But reading this thread , Phil w is using 175mm, so I think I'll stick with the 170's for a while. Might swap the 42 for a 38 tho ( looks in cupboards). And the try some climbing in the granny.
Slightly OT, if one is in granny , on a HILL, and forced to stop, what is best way to get going again, as I've not tried it yet.
Post by: Kim on 11 May, 2020, 12:38:09 pm
Slightly OT, if one is in granny , on a HILL, and forced to stop, what is best way to get going again, as I've not tried it yet.
The usual normal way to get going. (Is there more than one?) You just need to be good at low-speed balance. If you practice starting off in the bottom gear on the flat, it won't be that different (no freewheeling!).
The problem is that with a low gear and a lightly loaded rear wheel, you may find the wheel spins if the surface isn't conducive to traction (the Streetmachine isn't actually too bad for this, compared to lower recumbents). My preferred method is not to stop on steep climbs, but if there's no other option sometimes you may need to push the bike to somewhere flatter or less slippery.
Luggage is less of a problem than you'd expect, as the extra weight over the rear wheel improves grip.
Post by: Lightning Phil on 01 June, 2020, 07:30:25 pm
Late again!
My newly acquired streetmachine has 170mm cranks. 52,42,30, and a 9 speed block,11-34. I find big/ big and very useful gear, and do seem to spend a lot of time on the larger ring. I'm trying to spin, but 80-90 is about max for me, unless in short bursts. Not tried a BIG hill yet or the granny. Only 400km in so far. Was reading about shorter cranks and thinking about 160mm, but I'm 6'2" and have long ( big) legs, so spinning fast is not a natural for me. But reading this thread , Phil w is using 175mm, so I think I'll stick with the 170's for a while. Might swap the 42 for a 38 tho ( looks in cupboards). And the try some climbing in the granny.
Slightly OT, if one is in granny , on a HILL, and forced to stop, what is best way to get going again, as I've not tried it yet.
Hold a brake, pedal just before 12 o’clock. Release brake and push through pedal and get foot on other pedal even if not clipped. Keep pedalling. Haven’t tried that beyond 17% hill and in,y then because a foot had unclipped.
Post by: Lightning Phil on 12 June, 2020, 06:25:52 pm
Post by: mzjo on 15 June, 2020, 08:15:12 pm
Going back to conventional rings felt actually more spinny but since the turbo is put away between sessions there may be other reasons for that.
Biopace rings 48/38/28.
Post by: Blodwyn Pig on 25 October, 2020, 01:04:54 pm
Post by: Oxford_Guy on 26 October, 2020, 04:06:02 pm
Post by: Lightning Phil on 26 October, 2020, 08:40:29 pm
grasshopper
48 tooth chain ring SRAM 850 11 32 sprocket and give me 20.6 to 111 gear inches.
Way more range than I need for Suffolk and Norfolk.
Hmm that doesn’t work as the ratio from lowest to highest is just under 3 (32/11), but you say your ratio is 5.38 (111/20.6). You must have another chain ring up front.