I think it depends on how you maintain your drive train.
My approach is to replace the chain before it wears and wrecks the cassette and (eventually) the chainrings, so I would keep a cassette on each wheel (only the back ones, obvs.), replacing the chain before the cassettes get worn so that a new chain will skip on the worn cassettes. This has the advantage that if you need to mess with spacers to get the indexing right for the 2 wheel sets then you only need to do this once .
If you are of the mindset that you leave the one chain running until the worn chain wrecks the cassette I suppose you might be better swapping the one cassette between wheels, otherwise if you have cassettes on each rear wheel you might get different wear states between the 2 cassettes? Although does this matter? A new chain will slip on a too-worn cassette, but I don’t know if a worn chain on a slightly less worn cassette is a real problem rather than a theoretical problem.
Personally I think its better to keep cassettes, chains and chainrings in a condition such that none of them ever wear to the point that mismatches between old and new can result in, at the least, inefficiencies in the drive train or, at worst, graunching and tooth-jumping, chain-suck et al. This being so, having two wheelsets each with their own cassette mounted is no issue.
In addition, a cassette used for gravel and the like needs, ideally, to have a different ratio range than a cassette used for the road.
Swapping a cassette from one freehub to another can be a bit of a tedious process, especially if you have to remember any thin spacer to ensure that the cassette will index on the alternative wheel exactly as it does on the other wheel (otherwise you'll be having to screw about with the throw adjusters, cable tension and the like). But two wheelsets each with their own cassette means that you can align the cassettes for the same bike just once and then its done for all subsequent wheel swaps.
If you do want to swap a cassette from wheel to wheel, nevertheless, it's easiest if the freehubs on both wheels are the same and are also of the type that just pull off the hub. Some Hunt wheelsets are like this but there may be others. The freehub is retained in place during use by the hub end caps and the mech (Q/R or through axle) keeping the wheels in the frame, rather than by a separate hub lock nut or bolt.
You can then pull off the freehub with the cassette still attached and push it on to the empty location for it on the other wheelset. ... Or so I read. I have one such wheelset and the freehub does just pull off. You have to be careful not to knock or shake out the pawls but they don't leap out of their own accord. But I've not pulled one off with the cassette still attached myself. I can't see anything to stop that being done, though.
Last edited by Cugel on 30 Nov 2023, 9:20am, edited 1 time in total.
“Practical men who believe themselves to be quite exempt from any intellectual influence are usually the slaves of some defunct economist”.
John Maynard Keynes
Cugel wrote: ↑30 Nov 2023, 8:37am
In addition, a cassette used for gravel and the like needs, ideally, to have a different ratio range than a cassette used for the road.
This ^^.
Plus swapping cassettes (and/or disc rotors) sounds fine at first then after the 4th time you've done it, it quickly becomes a massive pain every time you want to swap wheels.
Just have two cassettes, one on each wheel.
My road wheels are set up like that - can just drop one set out and pop the other in, no need to swap anything over.
I have about 12 wheel sets (I really must count them !)
All have their own cassette and rotas.
It's an expensive option but the whole point of extra wheels is to facilitate fast changes. I have the tools to change cassettes but not the time or patience !
mig wrote: ↑30 Nov 2023, 9:15am
what about the mudguards?
Shouldn't make much - if any - difference and that's assuming the OP is using them anyway.
A 650b wheel with a 2.1" tyre won't be far off the diameter of a 700c wheel with a 38c tyre. The whole point of using 650b is to fit a wider tyre for more comfort and control at the harsher end of the gravel spectrum.
mig wrote: ↑30 Nov 2023, 9:15am
what about the mudguards?
A good point.
I have an e-bike for winter that also serves for gravel. The mudguards are wide enough for both the winter road bike wheels/tyres and the gravel wheels/tyres. But I won't ride on gravel roads with mudguards on as the chance of picking up stuff that could jam a wheel is much greater with mudguards, since they confine the jammer all the way up/down to the potential jamming points. No mudguards means that potential jammers get thrown off the trye well before they get to a fork, seat stay bridge or chainstay join.
Taking off and putting on mudguards can be a reet pain, so I don't ride gravel in winter when the bike concerned is set up with guards et all as a winter road bike. Come Spring, the mudguards come off for a few months and that bike goes a-gravellin'-oh in Fforest Brechfa and (now and then) The Cambrians. A nice light summer bike goes out on the now generally dry roads.
Mind, the bike shed does have some other bikes, including a lightweight bike with mudguards on. In Wales, it can rain even in summer!
Were I not trying to stop ridiculous consumption habits, I might have 20 bikes in that shed, for various niche purposes. So I confine myself to the 19 already in there. (Kidding).
“Practical men who believe themselves to be quite exempt from any intellectual influence are usually the slaves of some defunct economist”.
John Maynard Keynes
531colin wrote: ↑30 Nov 2023, 8:15am...... but I don’t know if a worn chain on a slightly less worn cassette is a real problem rather than a theoretical problem.......
if you use a chain that is slightly more worn than the sprockets it won't skip, but the sprockets will quickly wear to match the chain.
Hi folks, it’s a bit late and I’m tired, so I may be being a bit thick here… but assuming that if one runs two wheelsets, each with their own cassette, would each wheelset have its own chain?
Or would the plan be to run just one chain?
I’m thinking two chains surely?
LuckyLuke wrote: ↑30 Nov 2023, 11:55pm
I’m thinking two chains surely?
The only case where you'd need a different chain for each wheelset would be if the cassette sizes were dramatically different - say an 11-25 on the road set and 11-36 on the off-road set.
Even then it'd still work assuming of course you set the length based on the biggest cassette. It'd just be a bit slack on the smaller cassette but since the 11T remains constant, it'll never be completely slack to the extent it won't work.
Depends a bit on what gear system the OPs new gravel bike is running.
Cassette(s) aside, you might need rotor shims as well to avoid having to loosen and re-align the calipers on each wheel swap. I have one gravel bike where I swap between one wheelset with 622x35 tyres and another with 584x48 tyres, and I had to use shims on one of the wheelsets to avoid the rotors rubbing on the pads when swapping between wheels.
NickJP wrote: ↑1 Dec 2023, 8:14am
Cassette(s) aside, you might need rotor shims as well to avoid having to loosen and re-align the calipers on each wheel swap. I have one gravel bike where I swap between one wheelset with 622x35 tyres and another with 584x48 tyres, and I had to use shims on one of the wheelsets to avoid the rotors rubbing on the pads when swapping between wheels.
That's a good point! It's something I found out when I bought a second wheelset for my gravel bike. It was a few years ago and at the time those shim sets were expensive for what they are. However they were worth it to avoid having to faff around re-centring calipers. You just need to work out on which wheels the rotors are the furthest out (nearest the frame tubes) and pack out the other wheelset rotors to match. I run a light touring wheelset and a winter weather/gravel wheelset. I keep an identical cassette on each so that I can run the same chain. I check my chains regularly for wear and swap out for new before they reach a cassette-eating state.
