27 Speed Hybrid. How Many Useable Combinations? Is it really a 27 Speed?

[Lovacott]

Not sure why you are posting if not looking for advice.
As for fact, chains shouldn't skip.
I'd check out the park tools website on adjusting gears - their system works - if you have any interest in advice.
But haven't we been here before?

I was simply asking the question why a 27 speed is called a 27 speed?

I have taken a lot of advice from here and it is unfair of you to insinuate that I haven't. I have watched all of the Park Tools indexing vids and for the first few times, I actually had the laptop next to the bike so that I could be coached through each step. As a result, my old 21 speed Apollo runs like a dream (apart from being so heavy).

I checked the chain on the Voodoo this morning for stiff links (as advised by someone earlier on) and they all seem fine. The chain is the correct length, the B Tension adjustment is good, the hanger alignment is good.

I'm sure it can't be the cassette because I can stand up pedal hard in big front to small rear (top gear) without issue.

As stated earlier, on the stand, apart from some front mech rub when the chain is crossed over, the drivetrain on the Voodoo runs like a Swiss watch. I can say the same for when I ride it on the flat.

The issue only happens under load (hills etc) and only when I inadvertently make a bad gear choice.

Maybe I could fix the issue by spending more money on an upmarket drivetrain, but it's not an issue for me if I'm using the kit I already have correctly.

 

[Lovacott]

Chain tension does not cause skipping on a properly set up drive train. Ask Mark Cavendish!

Not strictly true because my chain doesn't skip at all until I put it under heavy tension so tension is at least a contributing factor.

I don't doubt that a much more expensive drivetrain could be the answer. If expensive drivetrains performed the same as cheap ones, nobody would buy the expensive ones.

My drivetrain is only one step above entry level.

 

[roubaixtuesday]

Maybe I could fix the issue by spending more money on an upmarket drivetrain, but it's not an issue for me if I'm using the kit I already have correctly.

Whether cheap or expensive, drive trains do not "skip" in any gear combination unless something is wrong. Cheap drive trains can be far more robust than expensive ones.

I've not intended any criticism, and wholeheartedly apologise if it's come across that way.

What do you mean by "skip"?

Is the gear changing into a different one, or is the chain slipping on the front chairing or rear cog? Or something else?

 

[Lovacott]

What do you mean by "skip"?
Is the gear changing into a different one, or is the chain slipping on the front chairing or rear cog? Or something else?

Best described as the chain lifting partially from a rear cog and then re-seating. Like it's changing gear but starting and ending on the same cog. The chain isn't slipping around the cog so it's not a dangerous fault. Happens in big to big and small to small under load and to a lesser extent, big to second big and small to second small.

Again, it's only under load.

 

[Ajax Bay]

I think @Ian H probably nailed this, when he offered a not sought after suggestion.

It might simply be a stiff link causing the chain to skip on smaller sprockets.

The chain and cassette are new. It is not slipping through wear.
I am surprised the OP can see the chain slip mechanism while they are putting down power: my experience is just that you 'feel' the jump - as the chain gives half an inch (staying on the same sprocket) - if this happens its new cassette and chain time.
If there is a stiff link, this should be visually apparent when the bike is on its stand (have chain on smallest sprocket).
I can think of no other mechanism with a correctly indexed derailleur to cause the symptom the OP is sharing. Edit: I'm not doubting they are feeling something amiss.

 

[Lovacott]

I think @Ian H probably nailed this, when he offered a not sought after suggestion.

The chain and cassette are new. It is not slipping through wear.
I am surprised the OP can see the chain slip mechanism while they are putting down power: my experience is just that you 'feel' the jump - as the chain gives half an inch (staying on the same sprocket) - if this happens its new cassette and chain time.
If there is a stiff link, this should be visually apparent when the bike is on its stand (have chain on smallest sprocket).
I can think of no other mechanism with a correctly indexed derailleur to cause the symptom the OP is sharing.

If you look above, I acknowledged the advice and checked the chain this morning. I've also used a chain checker along the length to see if it is maybe a rogue link (if such a thing exists?).

I can't see what is happening behind me, but what I feel is a "clunk" akin to what you'd get if you dropped down three cogs in one go.

I've looked down to see where the chain has ended up and it hasn't moved. Then again, it can't move up or down because the indexing is good.

Again, it doesn't happen in a stand and it doesn't happen on the flat.

Just under load and only when I make a bad gear selection.

 

[Blue Hills]

I was simply asking the question why a 27 speed is called a 27 speed?

I have taken a lot of advice from here and it is unfair of you to insinuate that I haven't. I have watched all of the Park Tools indexing vids and for the first few times, I actually had the laptop next to the bike so that I could be coached through each step. As a result, my old 21 speed Apollo runs like a dream (apart from being so heavy).

I checked the chain on the Voodoo this morning for stiff links (as advised by someone earlier on) and they all seem fine. The chain is the correct length, the B Tension adjustment is good, the hanger alignment is good.

I'm sure it can't be the cassette because I can stand up pedal hard in big front to small rear (top gear) without issue.

As stated earlier, on the stand, apart from some front mech rub when the chain is crossed over, the drivetrain on the Voodoo runs like a Swiss watch. I can say the same for when I ride it on the flat.

The issue only happens under load (hills etc) and only when I inadvertently make a bad gear choice.

Maybe I could fix the issue by spending more money on an upmarket drivetrain, but it's not an issue for me if I'm using the kit I already have correctly.

On a point of fact, I was insinuating nowt.
You said:
"I'm not looking for advice by the way.".
I rather hope that this doesn't go the bizarre route of the infamous dog touring thread.

 

[Lovacott]

On a point of fact, I was insinuating nowt.
You said:
"I'm not looking for advice by the way.".

If you read the thread title, I'm asking a question about why drivetrains are named by the number of possible combinations rather than the number of useable combinations.

Park Tool indexing videos tell you that you shouldn't worry about a bit of noise in the crossover gears because you would never use them anyway.

The noise is the chain attempting to derail because it's feeding into the cassette on an angle.

But as you are never going to use those gears, it's not an issue.

Electronic drivetrains are programmed to avoid crossover gears.

I don't have a problem with my drivetrain as long as I use it correctly.

 

[winjim]

3 x 9 = 27, it's as simple as that. It's probably more like 21 usable gears but if they called it that then how would you know what cassette was on it? And as everyone has pointed out, all the gears should be available, it's up to the rider to decide if they want to use the extremes. I thought nomenclature had moved more towards just stating the number of sprockets anyway, now that we've moved beyond 15 speed being state of the art. So I have an 11sp double and a 10sp triple, I wouldn't call them a 22 and a 30 speed.

Possibly now we're onto 12 and 13sp cassettes, manufacturers are worried that 9sp sounds a bit small so they're reverting back to listing the total number of gears.

 

[Ajax Bay]

"I'm not looking for advice by the way.".
I rather hope that this doesn't go the bizarre route of the infamous dog touring thread.

That thread sounds interesting. Do share a link. Always keen to explore a bizarre route, preferably non-tarmac.

The noise is the chain attempting to derail because it's feeding into the cassette on an angle.

'Fraid not. By the time the chain arrives at the sprocket, it's passed round both pulley wheels and the guide pulley wheel has eponymously lined it up perfectly with the desired sprocket (if you've got the indexing "bang on"). A less than perfect chainline (2.5% max) will mean the chain leaves the sprocket at a very slight angle: this causes minimal noise, nor slipping. The chain is not "attempting to derail".

 

[Lovacott]

3 x 9 = 27, it's as simple as that.

I wouldn't call them a 22 and a 30 speed.

True. An 18 speed could be a 2x9 or a 3x6 and they would be very different bikes.

With my 27 speed, I'd rather it was described as a 3x9.

 

[Lovacott]

'Fraid not. By the time the chain arrives at the sprocket, it's passed round both pulley wheels and the guide pulley wheel has eponymously lined it up perfectly with the desired sprocket (if you've got the indexing "bang on").

The return leg to the chainring isn't straight though. The further along the chain is up the cassette, the greater the angle. That's why front mechs rub the chain when the gears are crossed.

 

[roubaixtuesday]

Best described as the chain lifting partially from a rear cog and then re-seating. Like it's changing gear but starting and ending on the same cog. The chain isn't slipping around the cog so it's not a dangerous fault. Happens in big to big and small to small under load and to a lesser extent, big to second big and small to second small.

Again, it's only under load.

There must be something wrong either with the RD setup, chain hanger, or as suggested by others, stiff chain link, or some more mysterious cause such as wring speed chain.

But if it doesn't happen in combinations you don't use, you can just ignore it, of course.

As to your original question... as others have suggested, 3x9 would be a better description.

 

[Lovacott]

There must be something wrong either with the RD setup, chain hanger, or as suggested by others, stiff chain link, or some more mysterious cause such as wrong speed chain.

It's defo a 9 speed chain because I bought a KMC X9 as a spare and it's exactly the same. I've run through all of the links to check that there is no stiffness.

But once again, It's not a problem unless I use the combinations that every cycle forum tells me not to use.

I was simply asking why a 3x9 is labelled as a 27 speed when it clearly isn't.

 

[Ming the Merciless]

On a properly setup 3 x 9, it is 27 speed. I can use all my combinations without skipping.