rickrob 

I’m working on a 2014 Trek X-Caliber 5 29er. It was originally a Shimano 3 x 8 with 11-34 cassette.

The owner asked if I could make it a 1 x 8 since she never used the front derailleur and it was always rubbing on the back tire anyway. Also wanted to go to a 40 tooth cassette in back (11-40) to make it easier to climb hills.

The bike has a lower end RD-M360 Acera rear derailleur.

I originally tried a 30 tooth narrow wide chain ring with a 11-40 Sunrace Cassette. Installed the chain ring in the middle position on the cranks.
That worked well, but 30 tooth front / 40 tooth rear combination actually was a little worse than the combination of 22 tooth front / 34 tooth rear.

The rider really wanted the 22 tooth chain ring in the front. This bike already had a problem with chain suck occasionally and would jam the chain between the frame and 22 tooth chain ring.

So I added a 2.5mm spacer on the bottom bracket to move the chain line a little bit and put the 22 tooth chain ring back. That solved the chain suck problem.

The bike shifts OK and the RD-M360 works with the 11-40 cassette. But I’m still running in to problems.


1) The bike drops the chain on rough terrain.

I have removed 4 links already, and even added a 3D printed chain tensioner on the chain stay.

That added some extra tension, but I still dropped the chain up front.

The rear derailleur has a weak spring even though it is not that old. The original one was destroyed on a ride and was replaced with the same model. There’s no way to increase spring tension on the cage.
Also noticed the B screw adjustment does not make much of a difference. It always clears the 40 tooth cog. There is a lot of bounce in the chain, chain slap even with the chain tensioner.


2) When pedaling under load using the third smallest cog in back, it skips a tooth. “Snap-Clunk” and the cranks shift a bit.



What else can I try to solve these problems?

Could the tooth skip in the one gear be chain line related? Doesn’t seem happen with other gears.

Any recommendations for a rear derailleur that would work in this set up and increase chain tension?

I tried an RD-M592 9 speed rear derailleur but the lever where the shift cable attaches interfered with the chain when shifting off the 40 tooth cog.
The chain rubbed against the lever. Otherwise, it worked OK but was tough to get adjusted. Didn’t care for the lack of a cable adjuster on that model though.

Or have I screwed up here and this just isn’t going to work?

Thanks in advance for any advice or suggestions.

veganbikes

I mean the cheap stuff isn't going to work as well for 1X. Try the Microshift Advent stuff with a clutch that should help a little it is also designed for larger cogs in the back. If you ran say an 11-34 you might be OK but trying to do a 40 with that thing is not going to handle that kind of range well. It was designed to look the part but not really go on trails and handle much it is a wide tire hybrid with "long" travel suspension essentially.

Honestly though I wouldn't want wide range in lower speeds too many big gaps and that bothered me. Having a 7 speed 11-32 and moving to 9 speed 11-32 made a huge difference but going to 40 I would want at least 10 or 11 to have fewer big gaps. However it might not bother other people but if I was going to do it Microshift would be what I would do almost no question. Hate on them but for the price the AdventX stuff isn't bad a lot better than say Shimano's poor offerings in that price range though the nice Shimano stuff is hard to beat.

cxwrench

Only the 22 ring? Does your friend just climb trees?

70sSanO

What spring is weak? Pivot, B, or return?

Are you running a RoadLink derailleur extender to get to the 40t?

The 15t skip is odd. Only thing I can think of is bad cog spacing between the 15t and 18t and under load the chain wants to crawl up and then skips and drops back down.

The biggest issue is not knowing if things will smooth out if you get, say, an RD-M591, or go with a 24t... or will that just be throwing away money.

John

hokiefyd 

You might consider going to a 9-speed setup, for a few reasons. Sunrace's 11-40 cassette is spaced pretty conventionally. 11-13-15-18-21-24-28-34-40 I have one of these myself and it shifts pretty smoothly. You can also get a relatively inexpensive Microshift Advent clutched rear derailleur and front shifter combo in 9-speed (though they don't have Advent 9-speed shifters with optical gear indicators, if that is important to your customer). Microshift does make Acolyte in 8-speed, but wide range 8-speed cassettes have fairly wide spacing. The RD-M360 rear derailleur is a fine unit for hybrid bikes and pavement or light gravel stuff (I have a few of these derailleurs myself), but its springs are not stiff and it's not intended to have the tension required to keep a 1x drivetrain in check. This is why I recommend one of the Microshift drivetrains.

Since we're on here spending someone else's money...if she liked the 22-34 low combo she had before, she may be willing to go up to a 26t with the 40t cassette (it'd be the same gear inches value). This would give her the same low end range as her current drivetrain while still preserving some of the top end she'll lose. If she truly never does shift out of the 22t ring on the front, however, maybe it's a moot point.

fishboat

She (the owner) should avoid seeking 1x as a solution and learn how to shift her original 3x8 setup..problem solved.

rickrob 

Thanks for your input on this. I'm leaning towards the Microshift 1 x 9 setup. In one season she has gone from basic dirt trails in a park to green level and more aggressive riding on blue level trails with some good hills, rocks, logs and mud...
As you said, the RD-M360 wasn't really made for this type of riding, so it isn't going to hold up under these conditions. I'd like to get this bike to a point where it can handle the conditions she's riding in now , until she's ready for a better bike.

At least the front forks seem to be holding up on this bike...

I found these on Amazon, assuming the Microshift shifter uses the same cable as Shimano.

Microshift Trail Trigger Pro Right Shifter - 1x9 Speed, Advent Compatible
KMC X9.99 Bicycle Chain (9-27 Speed, 1/2" x 11/128"- 116L, Silver)
Microshift Advent Cassette - 9 Speed, 11-42t
Microshift Advent Rear Derailleur - 9 Speed, Medium Cage, Black, with Clutch

Maybe I should grab a 24 or 26 front chain ring as well.

70sSanO

But I’m running a 2x8 (24/34) with a 13-40 cassette. IMHO, everything is driven off the lowest ratio.

Was she able to use the 22/34, which is a .65 to 1, or did she need a lower gear?

I believe Microshift Advent goes to an 11-46 in a 9 speed. It all comes down to how low you need to go. I rarely use the 24/40 since the speed is so slow it is close to walking; the 40t is great with a 34 chainring.

The 24/40 ratio is .6 to 1. I‘m not sure I could use a 22/40 which is .55 to 1. Regardless, if you throw a 46t cog into the equation and run a 26t chainring you are at .57 to 1 with at least a greater than 2:1 top end ratio. If that works for her, especially if she is getting stronger, it might be a good way to go. It might even lead to a 28t or 30t chainring down the road.

John

rickrob 

She was struggling with the 22/34 on some of the hills -- so we tried going to the lower gear 11-40. I found the 22 /40 difficult to ride. Going with a 26 / 46 sounds like a good idea.

I looked for a Microshift 11-46 Cassette on Amazon, could not find it. I figured it would be good to go all Microshift just to make it easier to deal with. I'm not sure if I can use other cassettes with Microshift -- never worked with their products before.

hokiefyd 

All that will work fine together, yes. The shifter does use the same cable and housing as any other. The shifter comes with the inner cable as I recall (you supply your own outer). The Microshift 11-42 or the Sunrace 11-40 would work nicely. I have the Microshift 11-46 in 9-speed and consider that spacing to be too wide (I don't have it on the bike any longer). I don't own the MS 11-42, but I do have the SR in 11-40 and like that one. The MS has the same spacing...just a 42t large sprocket instead of the 40t large sprocket. Any 9-speed chain will work. An X9.93 would save a bit of coin...the only difference is the grey inner links vs. full nickel on the X9.99.

Good luck!

Edit: I think the Advent Trail Pro shifter has push-push shifting, and is not 2-way release...in other words, you cannot pull the upper paddle to upshift (smaller sprocket) even if you wanted to...it's push only. The more basic Advent trigger shifter has push-pull shifting -- push the lower paddle to downshift and pull the upper paddle to upshift.

70sSanO

I didn't spend much time, but they are out there...

https://www.modernbike.com/product-2...SABEgLKSfD_BwE

https://cambriabike.com/products/mic...iABEgIOkfD_BwE

You could probably get the shifter and RD and get free shipping.

John

rickrob 

Thanks-- I'll go with the basic Advent shifter since the push-pull shifting is what's on there now.

rickrob 

Thanks everyone for your help. Hopefully I'll get this sorted out and the bike will perform better with the Microshift 1 x 9. I'll follow up with the results.

hokiefyd 

The Xpress Plus is the push-pull shifter with the cartridge bearing inside (SL-M8195-R). The more basic Xpress shifter (SL-M819-R) doesn't have the cartridge bearing, but is also push-pull.

rickrob 

Just following up with the results. The MicroShift Advent 1 x 9 drivetrain was a huge improvement.

I left the 3D-Printed Chain tensioner on the chain stay, and made a chain guide / guard out of ABS that sits where the middle chain ring would be.
This is the prototype and the final one had a slightly larger diameter. I did that to make sure the chain has no place to go but the 22 T chain ring. It works well.

The bike has been ridden on rougher trails for the last month. The 1 x 9 set up shifts great and no longer throws the chain or skips any teeth on the lower cog.

70sSanO

Good job!

John