Want 34t/36t chainring

setspeed

Can anyone recommend a place to buy a cheapish middle chainring that will fit a Truvatix Firex crank? Looking for 34t or poss 36t.

Eventually I'm looking at dumping my big chainring and replacing with a bashguard - has anyone got experience with dual ring setup and which is best 34 or 36t?

Thanks!

robertpb

I use a 2 ring setup on Truvativ Firex with a Raceface bashguard.

If you keep the 22 inner ring and go for a 34 or 36 middle you'll need to change the mech to handle the 14 tooth maximum lift as most mechs are designed for 10 tooth lifts.

I put a Shimano SLX 2 ring mech on my bike it's made for 14 tooth differences.

Most of the 2 ring setups from the factory usually come as 22-36 or 24-38.

The best way to decide what middle to go for is down to where you ride, how often do you run out of ability to go faster on your current middle ring and when you use the outer what's the gearing ratio you want to go to.

An outer ring with 44 teeth only gives you 2 more faster gears than a 32 tooth middle.

This means if you turn the cranks at 60 rpm in the top gear outer ring you can get the same speed at 83 rpm with a midle 32 tooth, or 73 rpm with a 36 tooth.

Hope that helps

setspeed

I wasn't planning on changing the mech if i can help it. It's just that my middle ring is worn/needs replacing anway and i thought i'd use the opportunity to get rid of the big ring.
Wouldn't my current mech (Deore) manage to move the chain from 22 to 34?
May have to rethink my plans!

Anonymous

Realistically? you should be fine.
I've gone from 22/32/42 to 22/38 without changing the derailleur, and had no issues.

setspeed

yeehaamcgee:
Ah, that's what I wanted to hear!

robertpb:
I'll also go to that sheldonbrown website and have a play with the gearing ratios n see what the best setup will be for me.

Thank you both for your input! :-)

setspeed

Nutha quick question:

I'm going to pick up a 36t middle chainring tomorrow and stick that in place of my current 32t (leaving the big ring on for now until i get a bashguard). Will i have to adjust the front mech at all - if so, how?

Anonymous

probably not.
Stick it on, and see if it works. if it catches (highly unlikely) then you'll need to slide the front mech upwards on the seatpost a little bit.

tombate911

yeehaamcgee wrote:

probably not.
Stick it on, and see if it works. if it catches (highly unlikely) then you'll need to slide the front mech upwards on the seatpost a little bit.

If you do this you will also have to adjust the cable tension, then is many guides on the internet on how to do this, such as park tools,

nicklouse

but why would you need to move it up? as that would mess up the position for the "big" ring.

no adjustment needed if you intend on using the big ring.

but it will be stiff going into the middle ring. When you lose the big ring then adjustment will make things shift better, but i would look at a bigger granny ring as well. you can find 26 and 28 easily. not looked for any 24T but i bet they are out there.

setspeed

Nice one, thanks guys, I'll see how it goes - don't really want to mess with it unless I have to!

setspeed

Bit more advice needed - managed to balls it all up!
Fitted new 36t chainring, no probs. Took it out for a ride and when shifting from middle to granny ring chain overshoots and falls onto bottom bracket shell.
Then started messing with the limit screws - no joy. Then just got stupid and started adjusting the barrel adjuster and finally the cable itself. This is where i really effed it up!
I can get the shifting from granny to middle and back again running sweet, no chain rub on the mech cage, but it will not shift out to the big ring.

I guess i will just run it like this for a while anyway, cos i intend on getting rid of the big ring as soon as i get a bash ring, but it annoys me that i didnt manage to sort the shifting for all 3 rings. I thought that adjusting the H limit screw would sort it out, but no matter what i tried i could not get it shifting all the way out to the big ring, the mech wont go far enough out over the ring. Does this mean i have too much tension in the cable, or too little?

Anonymous

Too little tension.

setspeed

Thank!. I'll give it another bash (possibly literally) tomorrow.

nicklouse

read the info on Parktools.

setspeed

Starting to get really hacked off now!
After several hours, I have a reasonable idea of how the front derailleur works (which i didnt have before!), but no matter how i adjust it the chain doesn't like shifting from small to middle ring and vice versa - its a lottery whether or not it will go cleanly onto the ring (middle to small) or even stay on the ring once there (middle).
I have followed all the advice on Parktools and various other websites, and now im starting to suspect something else is wrong.
Maybe ive got the new chainring on wrong? I checked the position of the indicator tab thats supposed to behind the crank, and it is. The ring is a shimano deore ring - ive mounted it with the polished side and ramps on the inside (closest to the small ring) - can someone tell me if thats correct?
I havent yet adjusted the actual position of the mech relative to the seat tube.
Any ideas? Perhaps my mech just doesnt like going from 36 to 22?

nicklouse

12T is the max range for most front mechs.

like i said earlier going bigger on the granny is also a good idea.

setspeed

Mmm, I dont know whether to just cut my losses and order up a 32t ring now, to be safe!
Either that or get a bigger granny ring would a 24 sort my probs out dya reckon?