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Single Chain Ring

1K views 22 replies 4 participants last post by  kapusta 
#1 · (Edited)
Hi,

I am planning of switching to a single front gear 9spd bike. I don't like front dérailleurs for some reason :eek:ut: :crazy: My ride style is light trail/XC, but it also got to do the urban thing as well.

Thing is I don't want to run out of gears, i hate it when i am in the hardest gear but it is still easy going.

So i want to have the highest possible front chainring, that will allow me to service all the rear gears. Am i right in thinking that the standard single ring crack arm will only connect to a middle ring? and what would the highest tooth chain ring be for that, i was thinking 38T/42T?

thank you
 
#3 ·
I see you answered your own question. Yes, any chainring (with the same bolt pattern)will fit, but you'll do best with one that has no ramps, pins or shifting gates.

Decide on a cassette and figure what'll give you the necessary gearing off the largest cog.
Hopefully it'll be big enough for a high gear off the smallest, otherwise consider a larger ring and granny.

Meanwhile, if you're keeping your old double or triple cranks, use the middle position and consider filing all the teeth off your old outer, and using is as a combination bashguard/calf protector.
 
#4 ·
Cool, thanks for the input, I did answer one of questions, but what sizes would you recommend, can a 42T service all the rings on a 9SPD cassette?

I actually did that on my last bike (using the outer as a bash guard) that was stolen, so I am starting a fresh, I don't really want to do that any way because you end up using a mid size ring as your main chainring and you can't get fast enough on road.

I have to ask a super beginners question, what are ramps, pins and shift gates, they they those blobs and bit of metal on the chain ring, what are they for, gear switching?

Many thanks.
 
#5 ·
dobby156 said:
Cool, thanks for the input, I did answer one of questions, but what sizes would you recommend, can a 42T service all the rings on a 9SPD cassette?
The size of the ring is not the issue, it is the position on the crank. The "middle" position can access all cogs. I have a bike that I use a big ring in the middle position, but I needed to do a little filing on the crank to fit it.
 
#6 ·
dobby156 said:
....... but what sizes would you recommend, can a 42T service all the rings on a 9SPD cassette?

....... what are ramps, pins and shift gates, ....... what are they for, gear switching?
Size doesn't matter. (where have i heard that?) Since there's only one chainring the only mechanical effect of size is on chain length. Use whatever size gives you the best gear range with your cassette.

By ramps, pins and gates, I was referring to the modifications on chainrings to improive shifting. They are useless on 1x? setups, and the gates (cut down and/or thinned teeth) work against you since they can cause chains to fall off.
 
#7 ·
Cool thanks for the info. I know it is very much the case of what works for you, but do you think i will have enough rage to get most places, with 42T? or am i better off with 38T or 44T?

I am strong in the leg department, and quiet heavy too?

thanks
 
#8 ·
dobby156 said:
Cool thanks for the info. I know it is very much the case of what works for you, but do you think i will have enough rage to get most places, with 42T? or am i better off with 38T or 44T?

I am strong in the leg department, and quiet heavy too?

thanks
Well, how big is your big ring now, and how does that work out for you?

There is really almost no difference between the 42t and the 44t in terms of gear ratio.
 
#9 ·
Hi, my last MTB was stolen last yeah, that was a single front ring, i think it was a 36T with a 11 as the highest on the rear, and i found that it was hard enough so i could never go as fast as I wanted.

My current bike is a road bike (nothing great) that has 42T at the front and the highest at the back is 14T, again i am often limited by this.

I am starting to think i should of with a 44T (with a max of 11T at the rear)?

thank you very much
 
#10 ·
dobby156 said:
Hi, my last MTB was stolen last yeah, that was a single front ring, i think it was a 36T with a 11 as the highest on the rear, and i found that it was hard enough so i could never go as fast as I wanted.

My current bike is a road bike (nothing great) that has 42T at the front and the highest at the back is 14T, again i am often limited by this.

I am starting to think i should of with a 44T (with a max of 11T at the rear)?

thank you very much
Where is it that you are worried about spinning out? The road or on the trail? It is very rare for me to spin out my 32 / 11 combo on anything but pavement.
 
#12 ·
dobby156 said:
.... I guess my real question is will 44T still allow me to get up hills on the softest gear.
No one can answer that question except you. Back in the day my touring 10s (5x2 so that'll give you an idea when) was set up 47-51 with a 14-28 freewheel and I used it for loaded touring all over the Northeast. I managed to climb many hills that others with grannys were walking. Sadly, I no longer have that kind of horsepower, but still get by with my 42t.

Last week I watched pros climb the Manyunk wall in Philadelphia in 39/25 combinations at speeds rivaling many rider's flat ground cruising speed.

If you own rings, set the bike up with what you already own, using the longest possible chain (to provide for future changes) and try it out. Afterwards your heart and legs will tell you what changes to make.
 
#13 ·
dobby156 said:
The bike also has to be road worthy, so the road is my main concern. I guess my real question is will 44T still allow me to get up hills on the softest gear.

thank you.
You are going to find that unless you like to push VERY tall gears up singletrack climbs, that it will be nearly impossible to get a single ring setup to do what you are looking for unless you live where it is pretty flat. Even an 44t ring with an 11t cog can spin out on the road on a moderate decent, and pushing a 44t / 34 combo up a steep singletrack hill is not easy. I mean you can do it, (ss gearing is taller than that), but you will be climbing ss style.

So far as what works well for mountain, go look at the 1x9 thread. Most are running 32-36t rings.

In my experience, it is a little bit of compromise on one or both ends (high or low) to get a 1x9 to work on just mountain or road. Either you are spinning out sometimes, or pushing a very tall low gear. Road and mtb call for pretty different gearing. Just look at the size of the rings that come stock on road bikes vs mountain bikes. If you are now trying to get 1x9 to work for both road and mtb, the compromise with get far bigger. Plan on spinning out on the road or pushing a VERY tall gear on climbs.
 
#14 ·
cool you know what I'll try 44T and i'll see how it goes, if it is too hard, I'll get 42T, if I don't get the range still; I'll go back to my 44T and add a second ring.

I reckon I'll be fine, I am very leg strong, I live in a comparatively flat area, and I need to slog it out every now and again causes I need to lose weight.
 
#15 ·
dobby156 said:
I live in a comparatively flat area
That helps with a single ring setup a lot, as you don't need as tall OR as easy gearing.

Starting with the 44t sounds like a good idea in your case.

I have a 1x8 commuter bike (40t ring and 12-32 cassette) I do spin out often on the road, but I want the lower gearing because I am sometimes carrying a load (groceries, books, laptop, etc), and the bike is probably close to 40 pounds as it is with lights, battery, baskets, and fenders. And there are some pretty steep hills around here. I just enjoy the coasting when I can.

The tires you are running make a big difference as well. On my fs, I run knobby tires at low pressure (24-32 psi), and I find myself still pushing my 32t ring on road sections where I will easily spin out my 40t ring on the commuter with slicks @ 60 psi.
 
#16 ·
kapusta said:
That helps with a single ring setup a lot, as you don't need as tall OR as easy gearing.

Starting with the 44t sounds like a good idea in your case.

I have a 1x8 commuter bike (40t ring and 12-32 cassette) I do spin out often on the road, but I want the lower gearing because I am sometimes carrying a load (groceries, books, laptop, etc), and the bike is probably close to 40 pounds as it is with lights, battery, baskets, and fenders. And there are some pretty steep hills around here. I just enjoy the coasting when I can.

The tires you are running make a big difference as well. On my fs, I run knobby tires at low pressure (24-32 psi), and I find myself still pushing my 32t ring on road sections where I will easily spin out my 40t ring on the commuter with slicks @ 60 psi.
I was probably going to run on moderately thin tyres (for a MTB) considering its purpose, not too slick. Probably at a highish pressure for the road, then lower it for trail.
 
#23 ·
dobby156 said:
Thank you.

Just for future reference would i be right in thing that a short cage would be suitable because:

Difference in front + difference in rear = Cage length (in teeth).
So
0 + (34-11) = 23 Therefore Short?
Exactly! You've got it:thumbsup:

FWIW, I run a X9 short cage with a 11-34 cassette and double (22/32) up front with no issues. After going to a short cage, I'm pretty sold on the idea, and will continue to do so even if I loose a few gear combos (that I should not be using anyway).
 
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