I’m currently running (Shimano) 3 X 9 and wondering about trying a double chainset, and eventually moving to 10 speed.

Doing this on the cheap, can I just trim the front shifter movement down to middle and outer, and obviously source a 2 X chainset?

If that’s a dog’s dinner am I right in saying Shimano 10 spd front shifters have options for 2 or 3 X?

Oh and if anyone has any FAQs on such malarky please shout.

After gouging a slab of rock at Dalby on the weekend and losing a few teeth of my 44t bash ring, I’m planning on converting my 3 x 9 to a 2 x 9 on the cheap.

As a starter I am going to fit a proper bash guard and a 36 ring in place of the existing middle (already looking at some second hand items) to widen the gear range, limit the front mech range on the limit screw. Then as the rear cassette wears out fit an 11-34, shouldn’t be to long given it’s current state.

See how I get on and if my frame can cope with the conversion, before making the jump to a 2 x 10.

I’ve recently converted the one 9 speed bike I had to 2x. It’s a really easy process all you’ll need are some compact chainring bolts and probably also two new chainrings for a more useable range, but it depends on what and where you ride. I went for a 26, 38 combo. blackspire do some decent rings designed to be used on double set ups. So there’s no need for a new chainset at all.

Once you’ve ditched the big ring you just need to trim the front mech and wind the high limit screw in. It’s not a perfect solution, and you can still overshift on the front with little effort, but it’s 99% effective.

Shimano 10 speed front shifters can be converted to 2x or 3x via a small switch on the shifter body.

Cheers SJ

I hadn’t given changing the rings any thought whatsoever 😳

From that I presume you have a ‘gap’ where the outer ring was?

Step 1. Take big ring off
Step 2. Replace it with a bash ring like this
Step 3. Screw in ‘H’ screw on FD until it will no longer shift past middle chainring position
Step 4. There are no further steps, you have a double & bash and are ready to ride!

Optional bits: Once you’re happy that a double is for you, you can tweak things by shortening the chain a bit, try different chainring sizes, and consider a double specific FD.

perthmtb – Member
Step 1. Take big ring off
Step 2. Replace it with a bash ring like this…

Step 3. Screw in ‘H’ screw on FD until it will no longer shift past middle chainring position
Step 4. There are no further steps, you have a double & bash and are ready to ride!

Optional bits: Once you’re happy that a double is for you, you can tweak things by shortening the chain a bit, try different chainring sizes, and consider a double specific FD.

Is the correct answer. I don’t even bother with step 3. If you’re that stupid that you still try and shift into the big ring you don’t; have fitted then tough.

Sorry guys I forgot to add that I would probably want the big ring for speed.

Would it be fair to say that folk generally use the granny and middle when ‘downgrading’ to a double?

speed ? i can pedal in the middle ring, smallest cog at 25mph on the flat. Do you REALLY need to be doing more than 25mph ?

I’m confused as to what you’re actually going to do if you wanna leave the big one on there ?

Run the granny as a middle and the middle as a big with an outer ?

Would it be fair to say that folk generally use the granny and middle when ‘downgrading’ to a double?

Yes.

Sorry guys I forgot to add that I would probably want the big ring for speed.

And presumably you need the granny for getting up hills – this is a mountain bike we’re talking about isn’t it?

Which kinda begs the question – why are you thinking of converting to a double?

It’s a serious question. If you really need a 44/11 then best stay with a triple…

yes.

and watch your chainstays, a 26/38 shimano 10spd double is not suited to some frames where there is ‘plenty’ of mud clearance

I’d obviously assumed you were dropping the granny, which is the ‘norm’. As others have said, IMHO there is no need for anything over a 40 big ring on an MTB unless your a World Cup rider! A 38/11 combo gives you pretty much the same gear size as a 44/13 or big ring and two from smallest on cassette – so you’re only losing very top end.

In terms of the ‘gap’ you mention, there’s nothing. The only difference is on a non specific chainset that the spider mouting arms will be on the outside of the chainring.

Sorry for the confusion.

Rightly or wrongly I try and stay in the big ring as much as possible and would want a 39+ sized outer ring. Only on muddy drags or steep hills do I go to the granny if I can help it.

A 28/40 double crank would probably give the best gear spread if I go up to a 36 cassette (currently on 32s atm) so I was trying to work out if I can tweak my existing triple kit.

Weeksy, my knees would explode if I tried to spin 32 X 11 for any length of time. 😆

If you can get rings to fit your chainset there’s no reason why a 28/40 wouldn’t work. the principe is the same, you’d just have to adjust the low limit screw instead of the high on the front mech. You also don’t need to change chainring bolts if you’re just ditching the granny.

I went 2×9 on both my bike a while ago with middleburn duo cranks on both – one is 40/27 and the other is 42/29 – with an 11/34 cassette on the back.

I prefer the 40/27 on the front and I won’t be going 2×10 as the range is plenty – 27/34 is very spinny.

Went to double and bash years ago as I rarely used my big ring, I was frequently bashing it and catching my kecks on it.
Also, it was only a matter of time before it ripped my leg open.

Didn’t see the point and not looked back or missed them.

A 28/40 double crank would probably give the best gear spread if I go up to a 36 cassette

You’d still need to use the granny & middle positions if converting a triple to a 40/28 double. It’s just not possible to fit anything smaller that a 32T ring in the middle position on Shimano 104 BCD cranks, the attaching bolts would be too close to the teeth, and foul the chain.

You’d still need to use the granny & middle positions if converting a triple to a 40/28 double. It’s just not possible to fit anything smaller that a 32T ring in the middle position on Shimano 104 BCD cranks, the attaching bolts would be too close to the teeth, and foul the chain.

Cheers Perthmtb, this is the sort of stuff I need to take in to account.