Pushing RD capacity - advice please

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GideonReade
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Re: Pushing RD capacity - advice please

Post by GideonReade »

Hmm, that last is kind of begging for a definitive article sometime, someplace. I know there have been in the past (a younger CJ?, Sheldon B), but I don't know if anything up to date is around?
markjohnobrien
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Re: Pushing RD capacity - advice please

Post by markjohnobrien »

CJ wrote: 21 Apr 2021, 3:52pm
gregoryoftours wrote: 18 Apr 2021, 5:24pm If you do end up going bigger cassette with longer cage mech, any Shimano rear 8/9 speed mech, mtb or road, with suitable length cage will do, and 10 speed road mechs apart from tiagra 4700 which is an anomalous cable pull ratio. MTB 10 speed rear mechs have a different cable pull ratio and aren't compatible.
To the list of newly incompatible Shimano 10-speed mechs that won't work with their pre-2016 stuff, you need to add the GRX-400 gravel mech, which is basically a Tiagra 4700 with a longer cage. And it's a crying shame this mech won't play with older or fewer speeds shifters, because it has a MUCH longer cage, capable of reeling in a humungous amount of loose chain, that'll cope with even more total difference that their current MTB mechs!

But personally, I wouldn't run 8-speed chain in a 10-speed mech anyway. I think two speeds different is pushing it. If likely to work I would do it, but fit 8-speed or at least 9-speed pulleys. Two reasons: the 8-speed chain is physically quite a lot wider, so there's likely to be a bit of rub in a narrower cage when imperfectly aligned with a sprocket (which happens even in perfect systems thanks to a bit of dirt and cable friction), and because 8-speed indexing isn't as perfect in the first place, so you may need the greater sideways float of the slightly wider pulley bush. And yes, fitting different speeds of pulleys does change the width of the cage.

Going the other way, I found that fitting 10-speed pulleys in the old XT-shadow 9-speed mech I'm using on my gravel/road bike (because the GRX-400 I'd bought won't play with my pre-2016 Ultegra 10-speed STIs!) has significantly improved its shifting precision.
This post by CJ is so good, and so interesting, the thread should be in “Technical: too good to lose”.
Raleigh Randonneur 708 (Magura hydraulic brakes); Blue Raleigh Randonneur 708 dynamo; Pearson Compass 631 tourer; Dawes One Down 631 dynamo winter bike;Raleigh Travelogue 708 tourer dynamo; Kona Sutra; Trek 920 disc Sram Force.
GideonReade
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Re: Pushing RD capacity - advice please

Post by GideonReade »

Well folks, as advertised, today was test day, a clockwise loop from N Worthing to the coast, along W of Littlehampton, north to Barnham, and home, with 80m of Salvington hill at the end (the only hill :D).

She liked it. Can ride up the hill sitting, and made lots more use of big ring. Went off at a helluva rate, perhaps the old chain had glue in it.

All worked well except one inside FD chain drop - tweaked the limit screw 1/2 turn, lets hope that does it. TBH I found the FD a bit long winded to adjust, not helped by any extant cable adjuster. FD also is now at the bottom of its slot on the frame.

Summary of works: Replaced 53/42 with 50/38 and 11-23 with 11-28. New chain 2T shorter, now the RD doesn't touch its own nether parts.

For completeness, final photos below, at the "illegal" extremities.
Attachments
New, big 50T to big 28T, new chain - 2T
New, big 50T to big 28T, new chain - 2T
New, small 38T to small, new chain 2T shorter
New, small 38T to small, new chain 2T shorter
markjohnobrien
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Re: Pushing RD capacity - advice please

Post by markjohnobrien »

Your bike is much higher geared than mine: I have triples 22/32/44 or 24/36/48 and my lowest cassette is 12/30 on one bike with the rest 34 or 36.

Only one bike is 30/42/52 triple.

Still, I am more of a plodding tortoise than a speedy hare.
Raleigh Randonneur 708 (Magura hydraulic brakes); Blue Raleigh Randonneur 708 dynamo; Pearson Compass 631 tourer; Dawes One Down 631 dynamo winter bike;Raleigh Travelogue 708 tourer dynamo; Kona Sutra; Trek 920 disc Sram Force.
GideonReade
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Re: Pushing RD capacity - advice please

Post by GideonReade »

Well, it's not her only bike. And indeed, most of the others are triples geared to haul coal, or at least tents & grub, up hills. Ditto mine, although now my road bike is the high geared one - I'll be back when my knees demand, a new conversation as it's an Italian job.

We really only use these road jobbies for sociable but intermittently hardish morning loops on the flat. Well, hardish for us, couple of friends are GB triathletes (age grouped), they treat it as a recovery ride. Anyway, it's always fairly flat, the hill is only after we've split off, squad wouldn't know if we caught the bus up it. Usually we're in the tortoise part of the group, although we seem to have maintained better through lockdown than many, so on a roll at present, whatever beast represents midway between tortoise and hare?
GideonReade
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Re: Pushing RD capacity - advice please

Post by GideonReade »

Anyway, many thanks to all who contributed!
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elPedro666
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Re: Pushing RD capacity - advice please

Post by elPedro666 »

Great to hear it was successful without any overly-heinous outlay Image
GideonReade wrote:...most of the others are triples geared to haul coal...
...the hill is only after we've split off, squad wouldn't know if we caught the bus up it...
Image


GideonReade wrote:...whatever beast represents midway between tortoise and hare?
I'm picturing either a hare in a hardhat, or a tortoise with a shell shaped like an aero helmet!

I'm a trendy consumer. Just look at my VOG-L09 using hovercraft full of eels.

pq
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Re: Pushing RD capacity - advice please

Post by pq »

If that was me I'd be rummaging around in my spares box to tweak the cassette. For me, 50/11 is still way too high and you'll have jumps between gears that are too big. Ideally I'd replace the 11 with a 13, and other changes up the cassette as necessary, but a 12 would be an improvement and you could swap that without changing anything else I imagine. Depends what you have knocking around in the shed really, but I pretty much never run stock cassettes and the ratios I have are much improved for it.
One link to your website is enough. G
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CJ
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Re: Pushing RD capacity - advice please

Post by CJ »

pq wrote: 6 May 2021, 10:41am If that was me I'd be rummaging around in my spares box to tweak the cassette. For me, 50/11 is still way too high and you'll have jumps between gears that are too big. Ideally I'd replace the 11 with a 13, and other changes up the cassette as necessary, but a 12 would be an improvement and you could swap that without changing anything else I imagine. Depends what you have knocking around in the shed really, but I pretty much never run stock cassettes and the ratios I have are much improved for it.
It would be interesting to know what size of jump different people deem to be too big and why. And then ask them how they suppose, in that case, it is possible for anyone to be happy on single-speed or fixed?

Personally, I am not happy on single-speed and especially not on fixed! (IMHO 'freewheeling' is the loveliest word bestowed by cycling upon the English language!) Be that as it may, I am content with jumps of around 15%. I find that gives me fine enough tuning to optimise my effort and cadence well enough to any steady condition. But I am not a racer, I'm never looking for the last milliwatt of power. If the gear is a little low, so I'm pedalling a little too quick: I don't mind going a few percentage points slower and saving some energy for the next big hill. Speaking of steep hills, I don't mind jumps of 20 to 25% and will often change two gears at a time on those. Steep hills are seldom exactly the same gradient for long enough to justify any finer tuning than that and besides, the bike slows so immediately during a change that there's no point in making small ones!
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freiston
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Re: Pushing RD capacity - advice please

Post by freiston »

CJ wrote: 8 May 2021, 5:43pm
pq wrote: 6 May 2021, 10:41am If that was me I'd be rummaging around in my spares box to tweak the cassette. For me, 50/11 is still way too high and you'll have jumps between gears that are too big. Ideally I'd replace the 11 with a 13, and other changes up the cassette as necessary, but a 12 would be an improvement and you could swap that without changing anything else I imagine. Depends what you have knocking around in the shed really, but I pretty much never run stock cassettes and the ratios I have are much improved for it.
It would be interesting to know what size of jump different people deem to be too big and why. And then ask them how they suppose, in that case, it is possible for anyone to be happy on single-speed or fixed?

Personally, I am not happy on single-speed and especially not on fixed! (IMHO 'freewheeling' is the loveliest word bestowed by cycling upon the English language!) Be that as it may, I am content with jumps of around 15%. I find that gives me fine enough tuning to optimise my effort and cadence well enough to any steady condition. But I am not a racer, I'm never looking for the last milliwatt of power. If the gear is a little low, so I'm pedalling a little too quick: I don't mind going a few percentage points slower and saving some energy for the next big hill. Speaking of steep hills, I don't mind jumps of 20 to 25% and will often change two gears at a time on those. Steep hills are seldom exactly the same gradient for long enough to justify any finer tuning than that and besides, the bike slows so immediately during a change that there's no point in making small ones!
I have a triple chainset with a 9 speed 11-34 cassette and my percentage jumps on any one chainwheel are (low to high) 13, 15, 13, 15, 18, 13, 15, 18.
I have to admit that I usually don't pay much attention to what gear I'm in but I do change gear frequently and I frequently change more than one gear at a time. Not often but sometimes (and not every time I make that same gear change) it does feel that the jump was a bit too big for what I wanted and I go back to the original gear - so I suspect that this occurs when I'm making an 18% jump and when the conditions and my energy levels make me feel it more. I'm presuming this doesn't happen on 13% or 15% steps otherwise I would be feeling it a lot more often.
Disclaimer: Treat what I say with caution and if possible, wait for someone with more knowledge and experience to contribute. ;)
GideonReade
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Re: Pushing RD capacity - advice please

Post by GideonReade »

(CJ's question) It depends who I'm with. If I'm cycling in a bunch and especially if I'm one of the weaker riders (not uncommon), I really feel it if I can't find a just-right gear. At the other extreme, out with the grandchildren, I make all kinds of mess of my gears and it just doesn't matter.

I suppose another way of looking at is, if were training, we try hard to keep pace with the fastest, so perfect ratio is desired. And sometimes a tall gear, though indeed on our routes 50/11 is little used. If we're touring, we match pace to the slowest, or just potter, so it doesn't matter if we can find a perfect gear. OTOH touring we have much less control over what we might encounter, giant hills and/or headwinds. So happily trade high gears for low & wide.

Which, curiously, is what suitable different classes of bikes routinely offer. Odd that.
pq
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Re: Pushing RD capacity - advice please

Post by pq »

I ride fixed a lot in the very hilly southwest of France and get on well with it. But when I'm on a geared bike I'm very fussy about the ratios I have and am forever tweaking standard offerings to get a lower bottom gear. I'm particularly irritated by having gears too high for me to use. I'm really not sure why I'm so inconsistent but that's how I am.
One link to your website is enough. G
GideonReade
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Re: Pushing RD capacity - advice please

Post by GideonReade »

A few months later and we're doing more hills (new Club, or rather, Club's come out of Covid hibernation), so far, she's still happy. In fact, having got well dropped on her (light) tourer, and whinging about the weight of it (err, lightish), she was delighted to realise the OCLV was only 9.4Kg. And is now roaring away on it, and planning to treat it to a new, uber-light, saddle & seatpost.

Thanks again, to all.

Now it's my Pinnarello's turn. And it's all-Italian. New thread:
viewtopic.php?t=150560
wirral_cyclist
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Re: Pushing RD capacity - advice please

Post by wirral_cyclist »

cycle tramp wrote: 17 Apr 2021, 7:36am
Tigerbiten wrote: 16 Apr 2021, 11:23pm One option I thought of if you do get a long cage derailleur.
Keep to 53/38 double and drop the 11t sprocket.
Then fit a 32t sprocket to make up the number of sprockets to give you a 13/32 cassette.
It's may be the easiest way to step all the gears down whilst not moving the front derailleur.

Luck ....... :D
Oh, that is an elegant solution. A 38 chain ring turning a 32 sprocket should give a low gear of about 33 inches... low enough for most unladen bikes to cope with everything but the steepest of longest of hills
33 inch lowest gear?
You're having a laugh, normal people need 24 or lower, only die hard road warriors insist everyone else should just 'man up' and struggle.
I ride 6000 miles a year, average 12.3mph doing that so not exactly weak but I'd like 24 inch or lower gearing.
Will the chain gang all point and laugh, is that the problem? Chuck MTB bits on like CJ said.
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Tigerbiten
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Re: Pushing RD capacity - advice please

Post by Tigerbiten »

wirral_cyclist wrote: 10 Apr 2022, 8:23am 33 inch lowest gear?
You're having a laugh, normal people need 24 or lower, only die hard road warriors insist everyone else should just 'man up' and struggle.
I ride 6000 miles a year, average 12.3mph doing that so not exactly weak but I'd like 24 inch or lower gearing.
Will the chain gang all point and laugh, is that the problem? Chuck MTB bits on like CJ said.
I'll be the first to admit that a 33" first gear isn't very low.
But if you can get a cheap/free 32t sprocket then the rest of the mod will only set you back around £25 max.
£7 for a 13t lock ring , £5 for a mech extender if needed, then maybe £12 for a new chain.
It will be even more useful starting with something like a 50/34 compact double or even a 53/40/30 road triple.
But it's not a bad mod if you just want to shift everything one gear down.

Luck .......... :D
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