SoSmellyAir

If you need a larger gear range for steep climbs and descents then a 1X conversion is not the way to go as it almost inevitably reduces gear range in comparison to a 2X or 3X setup. And even if you manage to match the gear range, you will certainly have larger gaps between gears. My 1X conversion hybrid is for casual riding around the neighborhood with my son and visiting nearby restaurants and coffee shops. I have a 2X road bike for my regular cycling.

SkinGriz

You can just drill through the rivets and reattach the middle chainring with whatever bolts work. This might also allow you to fine tune chain line with washers for spacers or whatever.

pumpkinhed

This is something I wasn't aware of. The hub on the rear now is Shimano FH-RM 30 hub, and it's spec'd for 8/9/10. To fit an 11 or 12 do I need a new hub? And is clearance not an issue? Will have to add spacers? Is this going to cause any issues with shifting/alignment? 11 or 12 speed offers many more options it seems so my life might be easier if I can go that route. In looking at all the different parts I'm obviously concerned about compatibility, was hoping there'd be a good set I could find that would work.

Thanks so much for the suggestion!

pumpkinhed

Thanks for the response SkinGriz!

Not sure if I'm understanding your post, but are you recommending drilling out all rivets, removing all sprockets, and then reattaching a new chainring that works with the new chain/cassette/RD? Would there be alignment issues or can everything be adjusted? And if I drill out rivets do I need to tap to make new threads for bolts to reattach the chainring?

This sounds like a great idea and maybe ideal for my situation. Saw , is this what you're referring to?

pumpkinhed

I've been experimenting with this (1x) by trying to ride on the middle sprocket alone and switching only rear gears. It covers almost all the range I encounter (maybe I'm reimagining or exaggerating the terrain I ride on). 2x would definitely cover everything. My thinking was sacrifice some comfort (2x) to make a simpler system (1x) less prone to error. I also thought if I did get a x10 (now maybe 11) that the additional gears would make up for my needs form my current x8, and things would be close enough. I'm not racing or going on group rides where I have to worry about the pace. My goal being having a solid bike that shifts so I can think more about the ride, life, etc and less about the gears. I'd rather have a perfect shifter than the perfect amount of gears. And now come the IGH comments....

pumpkinhed

I want to say a big thanks to all the comments this post has gotten. I honestly thought I was going to get some suggestions of compatible groupsets, and instead I get so many great approaches/ideas that I never thought of. This section should be called the Grand Rounds, bicycle mechanics doesn't do it justice. I'm still trying to figure out what might work best, but this forum has broadened my horizons for sure.

Thanks so much!

cpach

To be clear: there is no difference between a freehub body made for 8/9/10 speed and 11/12 mtb for HG driver freehubs like yours. 11/12 speed road is different. A new Sram NX 11/12 cassette, a microshift cassette, a 1x11 Shimano cassette, will all work on your hub perfectly with no hacks or modifications. The only cassettes you can't run are those that use a xd or microspline driver.

cpach

1x also usually means a very wide range cassette. As 1x was catching on in popularity a few years ago, it became popular to pair a large cassette (>40t) with a 10sp derailleur with a rated capacity of 36t max, possibly with a longer b tension screw or a wolftooth link. This was/is a pretty good option to modify an existing bike to 1x. It works, usually okay, but it is definitely worse than a derailleur intended for a wide range cassette.

Given the pretty low cost of 1x drivetrains these days, I'm just recommending against hacking a wide range 10sp cassette with a clutched Sram or Shimano derailleur not rated for that size of you're buying new parts anyways—its just a poor value.

If you want a simple, city bike 1x setup with, say, a 9 sp 11-36, a narrow wide chainring and possibly a chain guide, it'll work totally fine with an inexpensive, nonclutched derailleur rated for that size (or reasonable close to it. )

SoSmellyAir

For the 1X conversion of my Trek FX 2, I replaced the stock 8 speed 11-32 CS-HG31 cassette with a 8 speed 11-30 CS-HG51 cassette to (1) fine tune my gear range and gaps and (2) have shiny silver drivetrain.

Why not go 1x10 if I was willing to buy a new cassette? Because the Trek FX 2, like the Scott Metrix 40 (Scott Metrix 40 Bike - 2014 | REI Co-op), comes with Shimano ST-EF51 integrated shifters (i.e., with built-in brake levers) which are limited to 8 speeds. So going from 1x8 to 1x10 would have further required replacing (1) rear derailleur, (2) shifter, (3) shifter cable, (4) pair of brake levers, and (5) pair of brake cables. Way too much expense and effort for a casual bike.

pumpkinhed

This is a good point on keeping your bike/parts together to save $. For me, this is my only bike and I'm not against putting money into it to make it work properly. Of course I'm not trying to burn money, but swapping out the mentioned parts and going with a 1x11 or 1x10 is something I'm comfortable with.

SoSmellyAir

Yes, I think this was SkinGriz 's recommendation.

Assuming that (a) the existing chain line (i.e., imaginary line drawn from middle chain ring to middle of cassette) is good (i.e., parallel to top tube from bird's eye view), and (b) new chain ring is the same thickness and attached to the middle chain ring position, then no. But contrary to SkinGriz 's recommendation, I would recommend against using washers or spacers to attach the chain ring to the crank arms.

No, I don't think so. If the holes in the carrier (after removal of rivets) are not big enough, carefully drill to enlarge each hole (while maintain the same center) such that the hole will fit a regular chain ring bolt and nut.

In that case, if the above drilling does not work out, you can spend $60 for new crank arms and $30 for new bottom bracket like I did.

SkinGriz

Like the video, except reusing the old crank arm.
I’ve done it twice. Been awhile, but I think once on drill press and once in vice.

Drill the rivets out. Reattach only the middle ring with whatever bolts and nuts closest fit the hole.

Then you can probably also take a link out of your chain.

NBD.

SkinGriz

Eh…

Regular washers and whatever grade 8 bolt/nut that fits are fine. Torque property. Ride around and torque again.

After that, you’d have to be one Bad MoFo if you managed to break that setup loose. Highly doubt it.

And maybe it’s a couple ounces heavier than bike specific chainring bolts? Again NBD.

That’s similar bolt strength as to how a lot of trucks bolts the driveshaft flanges together.

LesterOfPuppets

You can probably fit an M7000 or M8000 11sp on there. You just can't fit an 11sp road cassette on it.

As for culprit for poor rear shifting, a bent derailleur hangar is a common cause.

pumpkinhed

Thanks for the specifics, good to know a road won't work. I'm dumb enough to have tried it otherwise...

SoSmellyAir

pumpkinhed Any updates? Still shopping for parts?

pumpkinhed

Hi SSA,

Sadly, this project has put on hold due to work/relocation. The good news is I'm moving by a friend in a bike shop and can hopefully get some useful guidance from him. I've been speaking with him a bit about this project, and was his told his shop generally discouraged 'science experiments' with bikes (loads of gearing/parts swaps) though they will do it. Their philosophy is it's best to stick with the intended design of the bike, as many modifications invite as many problems as they solve.

In my heart I want to turn this into a 1x (maybe 2x), but have yet to move seriously in a direction. In the meantime, the bike is going into the shop to get a tune up, maybe some fresh eyes will make it smoother.

Thanks for your interest/input, I'll come back and give updates as they happen!

Jeff Neese

Unless it's been damaged or is very, very old, it's unlikely that your Acera derailleur is the culprit. Acera is not Deore quality, but it's certainly not junk and they usually perform well. Hence the term "cheap but cheerful" when referring to lower-cost Shimano components.

It's interesting that it works fine for a while after the shop works on it. What EXACTLY are they saying they did to it to make it work? It's unclear how much experience you have working on bikes, but you should learn to adjust shifting and braking and other minor tune-up tasks yourself. YouTube is your friend. Whatever the bike shop is doing to fix it, learn to do it yourself.

The first thing that comes to mind are cables and housing. Have the cables been replaced recently? Cables do stretch a little when they're new, especially the cheaper ones. Or maybe the cable clamp on the derailleur is not holding tight and it's slipping? It could be a number of things. Your new bike shop will hopefully be able to diagnose it once and for all. It's never wrong to replace all the cables and housing on a bike, especially if what's on there is "budget" oriented. Look for stainless steel, drawn and pre-streched cables, along with high quality compressionless housing. Jagwire is my go-to source for both cables and housing, but there are a lot of other good ones.

I agree with your friend at the bike shop. If you want to change gearing for a legitimate reason (or because 1x is all the rage these days and you want to be one of the cool kids) that's one thing, but to do a complete rip-and-replace just to make your shifting work right doesn't make sense. A 3x8 Acera setup should work fine and need few adjustments.

daywood 

I know I’m late to this discussion but I’ll just add that I’ve done two of these conversions in recent months using the Microshift AdventX 10 speed cassette, derailleur, and shifter. Both conversions were fairly easy to do, although in one case I had to round up a new wheel because the old one was set up for a freewheel. For one of the bikes, I just removed the small and large chainrings and kept the middle 38T. The other bike had a crankset with both chainrings attached to the spider. In that case I cut the spider down to where it attached to the smaller 40T ring. In both cases the chain line is fine because I retained the original crankset and bottom bracket. The AdventX components were easy to set up and so far my wife and I are liking the simplicity of the drivetrain. It has all the range we need.

base2 

It's easy to put the cart before the horse, sometimes.

If the adjustment works fine for a time after leaving the shop, but then gets clunky, my bet (as with the others already mentioned) is cable tension.

One question have is whether or not the shop mechanic attempts to shift through as many gears as possible with out the wheel moving. This will properly seat the cables & take up about 90% of the usual, so-called "cable stretch" that is common. From there, the mechanic should then proceed to set the cable indexing on the smallest cog in the usual fashion.

Your shifting issues may simply be the shop you are taking the bike to. Maybe not.

As noted, cadence can mean a lot. Especially with Shimano's lower end groups. The higher end groups tend to not be so flexy or made with such low grade mild stamped steel. The alloys themselves are higher grade & stiffer, even if the part profile & thickness is the same. The higher end groups tend to have more machining to facilitate better shifting. As noted above regardless of part quality level, strain on the chain has an effect on shift quality. It's just more apparent on some groups over others.

It seems that the engineering on the lower end groups went from making an acceptable group at a cost work well to making a group cheaper at the expense of working well. Tourney or Acera of 20 years ago is not the Tourney or Acera of today.

All that being said: If you find that your limit screws, especially the H screw that determines the indexing index just won't stay put, a drop of blue Loctite 242, can make it stay put the way intended. At the very least it won't hurt, especially if the screw has been adjusted a number of times. The cheap nylon lock feature tends to not crasp the screw threads very tightly after a few adjustments. Especially if the metal threads in are poorly/loosly machined as well. Which is usually the case with the worn-out/obsolete manufacturing equipment reserved for the lower-end groups & absence of costly quality control. A drop of Blue Loctite 242 is probably a good idea on the limit screws of any old derailleur that won't hold adjustment well.

But, yeah...If that doesn't work, there's a lot of information in this thread to point you in the right direction.

SoSmellyAir

Is that the way to "pre-stretch" the cables? That is a good tip I have to remember next time I am replacing cables.

Exactly. Riveted chain rings just do not appear to be designed for trouble free front shifting in the long run. Following what SkinGriz said above, maybe the simplest fix is to just drill out all the rivets and use bolts to re-attach all the chain rings.

PGHNeil

I just did the same 1x9 conversion to my 2019 Trek Marlin 7 over the summer that was done in that video. It cost about $60 and I have no regrets. I know my bike and riding style are different but we both have Acera groupsets and I'm weighing upgrading the rest of the drivetrain vs upbiking. I suspect the OP may be as well if he's talking about going to the LBS. Here's my impression:

- narrow/wide chainrings solve chain drop but not ghost shifting, that's a RD or cable adjustment issue or a bent derailleur hanger.
- a 1x groupset appears to have less friction in the mix
- the narrower the range on the cassette, the less wear and tear on the chain

Barring drilling out the rivets it's a no-risk conversion if you can swap in another square taper compatible crank with bolts from a co-op. That's what I did by stripping my old bike of its crank. There is a financial investment but I did it for about $60. I also kept all the old parts in case I want to try to do Trek's buy-back program and go with a newer model with many of the features I've wanted to upgrade now being stock.