converting 3x9 to a single speed

[100Tours]

Been there, done that..

 

You might also consider a 1x9 or a 1x10 gear arrangement as a half way measure.

 

1. My wife (newer rider) gets thrown by having 2 shifters to deal with. 1 shifter only means you have a much simpler gear selector to manage.

2. 1x9 means you lose 2 of your front rings (keep a ring in the middle position maybe to keep the better chainline). You would do well to buy a straightcut wide/narrow chainring for this (i.e. no shifting ramps/missing teeth), and Rapide is a good place to start. This is to keep the chain on the rings without having a front derailleur to hold it in place.  

 

In my experience the wide/narrow ring will hold the chain in most circumstances. If you need better chain retention you can get a bash ring (wow I'm showing my age), or a chain guide. The chain guide is probably the more expensive option, and the bash ring is also a nice option for protecting the chainring.

 

Bonus - if you want to keep going you can then get rid of the cluster and rear deraileur too.. you've spent no more than you would have, but you've tried out a half-way stop on the way.

Edited April 17, 2020 by 100Tours

[ChrisF]

Grunder WELCOME to the Hub.

 

This may offer you some nice reading, and viewing .... https://community.bikehub.co.za/topic/181779-mongoose-rebuild-project/?hl=mongoose

 

 

 

PS - sorry, just finished a 13 hour work stint, so I have not read your full thread.  Sorry if I am repeating anything.

[BenReaper]

Thanks RW

 

Look the riding she will be doing is mostly urban with the kids either following her or with a kid on a bike seat (current setup).

 

Nine out of ten times the bike will not see a 'trail'.

 

But I will keep the oval chainring in mind when the time comes and she wants to do a bit more adventurous stuff.

 

you mentioned:

"Now that you know which it is you can then measure the BCD of the chain ring (This basically only applies to 4 bolt chain rings) - the way you do this is by measuring the distance between two diagonal bolts. Now I can guess with probably a 99% certainty that the 3x has a 104 BCD"

 

Educate me why is this needed?

 

The bike is a 650b.

So far the discussion is about the front chainring.

 

you guys are suggesting 32t or 30t.

 

 

Looking at the Rook Cycles site they are selling 44t and 48t chainrings.

 

Why would they only focus on these big sizes?

Jis ou maat, het vir jou anderkant ook inligting gelos.

 

Regarding you're questions around the chainrings. Mtb cranks generally have 4 bolt holes chainrings and in some brands they are direct mount, whereas road cranks have 5 bolt holes for the chainrings.

 

As mentioned above the Bcd is the diameter of the holes, you can determine youre bcd by measuring the distance between two oposing holes.

 

I'm attached a few images of the different types of chainrings for reference.

[J∆kk∆ls]

Pichas when ya done! 

[PhilipV]

Hi

 

While keeping busy during the lockdown I am browsing bike sites.

 

Found Rook Cycles

https://rookcycles.com/

 

My wife fell in love with the colors and what not.

 

 

So...I am planning on converting her bike to a single speed.

 

Now, I have ZERO experience in building and speccing bikes.

Thus assistance will go a looong way in assisting me with the project.

 

Info on her current bike.

She has an Avalanche Prima Donna (year unknown). As I was upgrading my bike she got my old parts to upgrade her bike also.(the Prima Dona is a VERY basic bike!!) So far I have upgraded her gearset (my old 3x9 from my big nine 500) and she has a upgraded fork and hydraulic disk brakes. With the gearset change I also had to replace her rear hub as her old hub was not compatible. It's a Shimano 36 spoke hub.

 

Ok so the idea is simple. I want to put a freewheel cog on the rear. and the front setup needs to change to a single chainring.

 

1st question. Can The cassette just be taken off and the freewheel be added? Or will I need to replace the rear hub also?

 

2nd question. The front (3 chainrings); I see people are mentioning that mtb cogs have 4 bolts and standard cogs have 5 bolts. Does that mean that I will have to replace the entire crank system for the conversion? OR, can 2 of the chainrings be removed to only leave the big one? (this might be a dumb question shedding further light on my ignorance on bike upgrading) **Note to self, I am too reliant on bike shops**

 

3rd. question (if I need to replace the crank). Will I need to replace the bottom bracket as well or will the new cogs work on the current one (assuming its a square bb)?

https://rookcycles.com/collections/parts-and-components/products/crank-set-chain-ring

 

I can't find decent specc info on the Prima Donna to know the ins and outs. What I can tell you is that the complete groupset came off my Merida big nine 500 (2014) if that helps.

 

 

I think that's about it. Fire away!

I went searching for a Merida big nine 500 and found this on a Singapore site.

 

1st question:

Yes, the cassette is taken off, and replaced by a single chainring and spacers.

Something like this.

https://www.rapide.co.za/product/rapide-singleminded-cog-and-spacers-kit-2/

If her chain isn't too worn, then that can be reused.

You will need something to keep tension on the chain, the current derailleur can be reused with some hacking and bodging, but adding a tensioner is more elegant.

https://www.rapide.co.za/product/rapide-tension-r-single-speed-chain-tensioner/

 

I'm not fond of my spring-loaded tensioner, as it's a bit noisy, so I use.one of these.

https://www.chainreactioncycles.com/za/en/dmr-simple-tension-seeker-single-speed-kit/rp-prod10009

 

 

2nd question:

If her crank looks like this one ( https://www.sportandleisure.com/shimano-fc-m522-10-speed-octalink-chainset-170mm-42-32-24-black-deore-m522) then it's a 104bcd chainring that you put in the same spot as the middle ring. You'll need shorter chainring bolts than what's currently on it, but those are a cheap, but very valuable add on when you buy the ring.

 

https://www.rapide.co.za/product/rapide-double-chainring-bolt-set-of-5/

Buy a 5pack, put the spare in the toolbox as you will lose or strip one.

 

If you can reuse this crank, then the BB can stay.

 

Here is mine, Rapide chainring, Cog and bolts with the DMR tensioner. Old crank and 10spd chain.

[Grunder]

A lot of great info thx guys.

The euphoria has worn of a bit I am afraid (wife's). But you did give me a good idea. I might change the front x3 with the oval Rapide cog and make it a 1x9 system. Too many gears confuses her and she almost always goea to the front to change when things goes south. This would make it less complicated.

Edited April 20, 2020 by Grunder

[Grunder]

But...

 

The SS is not out of my mind yet........

[ChrisF]

"Accidentally" adjust the limit screws in the front ... locking it to the middle ring .... then she has a 1x ....

 

 

the 1x really is MUCH easier to understand and use. 

[Fat Boab]

Or 3x1?

 

I'll get my coat...

[ChrisF]

Or 3x1?

 

I'll get my coat...

 

Hey, us oldies grew up with a 3-speed .... one lever, no way of getting confused ...    

[Fat Boab]

3x1 not 1x3...????

 

 

Hey, us oldies grew up with a 3-speed .... one lever, no way of getting confused ...

[PhilipV]

A loy of great info thx guys.

 

The euphoria has worn of a bit I am afraid (wife's). But you did give me a good idea. I might change the front x3 with the oval Rapide cog and make it a 1x9 system. Too many gears confuses her and she almost always goea to the front to change when things goes south. This would make it less complicated.

How hilly is it where you ride?

If it's flat, then the 1x9 can work, but the beauty of 1x only works with wide range cassettes, and the standard 1x9 might not have enough of an easy gear for her to climb with.

[Grunder]

How hilly is it where you ride?

 

No, the Freestate is famous for its hills...

 

 

When I first moved to Bloem I was told the joke that the Freestate is so flat...; you and your wife would have and argument and she leaves.  2 Days later you can still see her on the horizon