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

Lovacott

Über Member
I've been commuting on my brand spanking new Voodoo Marasa Hybrid for the last fortnight.

Things I have noticed.

1. On the middle ring at the front, the chain skips on the small ring at the back when under load.

2. On the big ring at the front, the chain skips on the three largest rings at the back under load.

3. On the small ring at the front, the chain skips on the three smallest rings at the back under load.

It's no big deal for me. I've sussed out the combinations which work for each hill type and I'm more than happy with the bike and setup and I can find gear combinations for every circumstance.

But why do they call it a 27 speed when it clearly isn't?
 

Cycleops

Legendary Member
Location
Accra, Ghana
Something not quite right there. It’s a new bike, I should take it back.

Try to maintain a good chain line by avoiding extreme combinations.
 
  • Like
Reactions: C R
OP
Lovacott

Lovacott

Über Member
Something not quite right there. It’s a new bike, I should take it back.
I've fine tuned the arse off it and everything is bang on.

Fact is, on the flat, I can select any combination I like and it's great (apart from some rub on the front derailleur on the crossovers between big to big and small to small).

But under load (especially on hills), the bike is at it's best with the chain running in a pretty much straight line between front and back.

I get 19 combinations which perform flawlessly with the other 8 combinations being questionable.

Simple answer is that I only use the 19 combinations which work flawlessly and ignore the other 8.

So why do they call it a 27 speed when it isn't?
 

Gillstay

Active Member
I've fine tuned the arse off it and everything is bang on.

Fact is, on the flat, I can select any combination I like and it's great (apart from some rub on the front derailleur on the crossovers between big to big and small to small).

But under load (especially on hills), the bike is at it's best with the chain running in a pretty much straight line between front and back.

I get 19 combinations which perform flawlessly with the other 8 combinations being questionable.

Simple answer is that I only use the 19 combinations which work flawlessly and ignore the other 8.

So why do they call it a 27 speed when it isn't?
Well to answer your question, how else would you do it when some of us would get a full 27 choices and others like yourself only get 19 !
 
  • Like
Reactions: C R

Ajax Bay

Guru
Location
East Devon
I've fine tuned the arse off it and everything is bang on. Fact is, . . .
An answer, a question and an observation.
Riding a 3x9 gives you 27 discreet chainring-sprocket combinations. Here's an example:
https://www.gear-calculator.com/?GR...21,24,28&UF=2150&TF=90&SL=2.6&UN=KMH&DV=teeth
There are two ratios the same (3:1 and 2:1). What do you suggest would be a better name for this set up? A "maybe 24 speed"? Would that be clearer? For example: 21sp, 24sp, 20sp, 22sp 10sp, 1x10 tells me what I (and you) need to know.
I can ride in every one of my 27 combinations. Large/large and the front cage (triple front mech) rubs to tell me. Small/small and the return section of the chain rubs against the chain round the tension pulley wheel (because I'm running it slightly beyond the capacity of the long cage rear mech). Both those noises are fine: it's just my bike saying "come on: get it right!" My chain does not 'skip' in any combination (and I bet I'm typical in our small virtual community).
Speaking of clarity, please could you say what you mean by "skip"? Do you mean the chain derails to an adjacent sprocket?
Fact is (being a bit harsh), your fine tuning is arse and quite a bit is bang off. And on past experience, you will say all the advice you receive is misconceived.
 
OP
Lovacott

Lovacott

Über Member
Speaking of clarity, please could you say what you mean by "skip"? Do you mean the chain derails to an adjacent sprocket?
Fact is (being a bit harsh), your fine tuning is arse and quite a bit is bang off. And on past experience, you will say all the advice you receive is misconceived.
Skip as in it doesn't sit tight on the sprocket under load and jumps every few revolutions or so.

If it was trying to move down the cassette in big to big, it wouldn't be trying to move up the cassette in small to small.

I'm not looking for advice by the way. I was simply making a factual observation on the reality of a 3x9 set up.
 
OP
Lovacott

Lovacott

Über Member
I have a 3x9 (sora) which works flawlessly in every single gear combination.

I wouldn't use the extremes deliberately, but they all work.

There's something wrong with your setup. Even with severe cross chaining, gears don't "skip".
They do work flawlessly except under load.

With the bike on a stand, the only noise I get is on big to big and small to small where the front mech rubs slightly on the side of the chain. The changes though are smooth and precise.

My mech hanger is perfectly aligned, the stops are set perfectly and the cable tension front and back is bang on. There is no delay when shifting either up or down front or back. The chain is lubricated with a decent quality chain oil and everything is spotlessly clean.

Riding on the flat and going through every combination, I get exactly the same smooth and precise shifting with no skipping.

Under load however, although the changes are precise and smooth, small to small and big to big will skip a bit.

To a lesser extent, some of the other close by combinations will also skip a bit.

It's not an issue for me and as I said before, I am simply making an observation.

One possible aggravating factor is that I prefer power over cadence speed (I'd rather push hard than pedal fast). This probably comes from years as a kid riding single speed bikes. Power increases tension on the drivetrain.

I've learned over the last year to keep my chain as straight as possible between front and back so I will select combinations which do that.

However, sometimes I forget where I am and make a change which breaks that rule (more so in the first week as I got used to using trigger shifters for the first time ever).
 
Last edited:
Location
London
I'm not looking for advice by the way. I was simply making a factual observation on the reality of a 3x9 set up.
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?
 
  • Like
Reactions: C R
One possible aggravating factor is that I prefer power over cadence speed (I'd rather push hard than pedal fast). This probably comes from years as a kid riding single speed bikes. Power increases tension on the drivetrain
Whilst I don't doubt your power for a moment I can assure you it is well below that on my setup- which is on our tandem.^_^ And both front and rear mechs are slightly beyond their nominal capacity.

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

If the chain is skippng, assuredly there is something amiss.
 
Top Bottom