clarkbre

Just want to start with I've searched for this a bit and it has left me wondering....

I'm building an old rigid MTB for riding on nearby MUP's and gravel rail trails, nothing hardcore. Going at the pace of my 10 and 13 year old sons, our cruising speed is usually in the 12-14mph range and the largest bumps we see will likely be concrete lifted by an incidental root.

My plan is to go with a 1x8 drivetrain (This is not a thread to discuss why 1x8) using a 32t chainring, 11-28 8 sp cassette and Shimano STX-RC rear derailleur. I'd like to use a Surly Stainless Steel Bike Chainring.

The more I read on forums and facebook groups, I see the recommendation to use a chain guide, narrow-wide chainring and/or a clutched derailleur. Most of these related to 1x MTB's with large range cassettes (11-42 at times)

Question: With the type of proposed riding, gearing and speed that the bike will be intended for, is a narrow-wide or chain guide necessary? If yes, my preference would be to start with a NW but it seems that a 32t, 94mm BCD 5-bolt is challenging to find.

Any thoughts or info would be great!

jadmt

I have a 1x8 on my vintage mtb and not a narrow wide nor do I have a chain guide and never ever have I had an issue.

bboy314

I’ve ridden a lot with a similar setup and it’s been fine. You can always throw on a front derailleur (as a chain guide) if you find yourself throwing the chain.

Note that the pic in the previous post is a clutched Box derailleur (I believe), which may help with chain retention. Shouldn’t be much of an issue if you’re not mountain biking though.

SoSmellyAir

In my experience with a 1x8 drivetrain using a 38T chain ring and a 11-30 cassette, I need a chain guide to prevent the chain falling off on the inside.

Converting Trek FX2 to 1x - Bike Forums

Maybe because it only had a cheapo Acera RD? Maybe if I go 1x10 on that bike I won't have the problem anymore?

TiHabanero

For about 10 years I used exactly what you are proposing, a1x8 drive without a chain guide or narrow-wide ring and it occasionally threw the chain while shifting at the extreme ends of the cassette. The derailleur was a Crane GS with the notorious weak spring and I believe it was this spring that caused the issues. Installed a double ring crankset and changed to an XT derailleur and now it no longer throws the chain. No guide, no narrow-wide, no front derailleur.

Ironfish653

For a rigid / hard tail, especially one that is primarily going to see use as a path-bike, clutched RDs and NW rings aren’t really necessary.

Narrow-Wide is good for guiding a skinny 10/11/12-sp chain, especially when it’s seeing a lot of deflection, at the extreme ends of the cassette; 8-sp is a lot more tolerant that way; any 1X / Fixie / BMX ring should work just fine for your intended application.

Clutched RDs really shine on full-suspension bikes, where they play an important role in controlling chain tension, while the rear wheel is moving around in relation to the crank/BB, and changing the effective chainstay length/angle.
Unless you hit a lot of hard fast chatter on your hard tail, it has more capabilities that you won’t need; any decent MTB RD should perform fine here, too. (I’ve used STX, old 90s LX/XTs, even 500 Exage and a SunTour XCD to good effect)


The only change I’d make to the proposed setup is going bigger than a 32t ring; this sounds like a 26” bike, and unless you’re planning on doing a lot of climbing and technical trail work, you may find yourself running out of gears when you’re just cruising the rail-trail. My current setup has a 40-13 top gear (1x6) and it’s pretty close to spinning out at 15 mph.
You may want to bump up your chainring to 36/38, or bigger, if you don’t want to ride everywhere at 90rpm.

jadmt

I agree I have a 39 tooth chainring and 11-42 cassette and for tooling around on bike paths and dirt roads it is perfect. still low enough to climb pretty well and I can cruise 15-20mph if needed.

hokiefyd 

I've also used a similar setup. Like some others commented on, I had issues with the chain jumping during shifts, especially at the large end of the cassette. I was using a non-clutched, Shimano Acera, derailleur and the "shock wave" of the chain shifting from one of the larger sprockets to the next-smaller sprocket would sometimes make its way to the front and cause the chain to skip off the ring. As I recall, this was more prominent during light pedaling, where there wasn't a lot of chain tension on the top run of the chain, which allowed that "shock wave" (for lack of a better term) to propagate forward. When shifting under enough pedal pressure, I didn't seem to have as much of a problem. The chain drops would, of course, happen at the most inopportune time and I eventually tired of it and bought a cheap $8 narrow-wide ring from Amazon.

veganbikes

RaceFace NW chainrings aren't super expensive when I got mine it was around the same price as the Surly ring. You may not drop a chain but the little extra assurance with the N/W chainring isn't bad. My set up is a 1X9 38t 11-32 cassette and has been pretty flawless. Had a few issues when it was a 1x7 with a Surly ring but the N/W took care of it when I went 1x9

jadmt

ditto on the race face I have one albeit in 42 on another bike but that one has 1x11.

clarkbre

Thank you all for your insight and information. I always appreciate real world feedback

Yes, this is a rigid MTB that will be running 26 x 2.1 tires. The area that we live is a bit hilly so I was focused on still retaining low gearing for the incidental hills. Looking at gear inches, the original 32t, 11-28 8 sp range would be from 30 - 76. Changing up the chainring to a 36t would definitely open up the top end more, yet still keep the bottom relatively low at 33 - 85. And, in all reality, my legs aren't really up for much more to maintain a constant speed.

To throw another option out there, I also have a 9 speed 11-32 cassette sitting on the workbench. At this point, I'm thinking that may be an even better option. With a 36t up front, it would have 29 - 85 gear inches so it would give me one gear lower with the same basic top end.

Again, I really appreciate the positive responses and good information.

Here's where I'm currently at with the build:

'93 Trek Antelope 830 18" frame

tFUnK

Have also done 1x without chain guides before narrow wide was a thing. Worked fine but this was before the days of wide range cassettes. I think it can still work but I've also dropped chains on 1x with a narrow wide chainring and this was on a road bike so it's always possible to drop a chain.