Converting 18 speed to 27 speed

nobbyy

Hi all

This may be a stupid question - but here goes anyway.

I would like to convert my bike from 18 speed to 27 speed.

It has aTruvativ hussefelt crankset with x2 chainrings and a rock guard.

My question is - can I simply replace the rockguard with a 42 or 44 tooth sprocket to convert to 27 speed?

Thanks for any help you can give.

Whytepeak

You may well be able too.

However, check that your front mech can shift 3 chainrings, and that your rear mech is long enough.

Then it will work.

EDIT - you may need a longer chain too.

nicklouse

yes,
add a ring. new chain, adjust the high stop on the front mech (and possibly the position) and make sure the shifter is set right.

and also check that the rear mech has the range.

nobbyy

Wytepeak and Nicklouse -thank you very mcuh for your prompt and helpful replies.

Couple of further quesitons:

Is it likely I will need a new chain - how do I tell if it is too tight?

Dont understand the issue re the range of the rear mech - can you explain please?

Thanks again!

nicklouse

you WILL need a new chain as your old one WILL be too short.
It was set up for a 32T big ring not a 42T or 44T big ring.

range have a look in the FAQs. it all depends on what is fitted now. (you may require a new rear mech).

paul.skibum

Rear mech may need to be long cage instead of short or medium - I dont really understand cage lengths though so I'll shut up now!

I chucked a triple set of chainrings on my DH bike when I needed it to go up hill as well as down and it was no issue although I added the mech myself - did nothing to the rear mech

Lee373

Hi
I know this is an old post but am after the same advice. I have had a few carrera krakens. I do mostly country lane rides so there’s mostly climbs and fast down hills. This year they’ve changed the kraken from a 27 speed to an 18 so there’s no range in the gears. I was wandering if it’s possible to strip all the guts off and replace everything with the old 27 speed setup. Thanks

Lee373

They’ve even splashed a fat memory foam seat on it which weighs more than the old bike

Lee373

OR.. can anyone recommend a bike that’s a 27 speed,120mm fork travel, 22” fame 27.5 or 29er and under 15 kg

karljeff72

Sounds like you need to build that yourself

reaperactual

Lee373 said:

Hi
I know this is an old post but am after the same advice. I have had a few carrera krakens. I do mostly country lane rides so there’s mostly climbs and fast down hills. This year they’ve changed the kraken from a 27 speed to an 18 so there’s no range in the gears. I was wandering if it’s possible to strip all the guts off and replace everything with the old 27 speed setup. Thanks

Gear range isn't relevant to the amount of gears.

The only thing to consider is the tooth count difference between granny ring and biggest rear cog (lowest gear ratio) for climbs and the tooth count difference between big chainring and smallest rear cog (highest gear ratio) for flat out top speed pedalling.

If you compared the specific ratio difference between your current 27 speed and the new Krakens 18 speed drivetrain more than likely the climbing gear would be the same or easier on the 18 speed.

The highest gear will probably give you slightly less flat out pedalling speed as the big chainring on the double crankset will have a slightly smaller (lower tooth count) size than your current triple crankset.

Yes you could swap everything over but highly likely it won't make enough difference to notice.