Need help with Drivetrain Update
 

Hello everyone, I'm an older lifelong cyclist that recently had my beloved old yeti mountain bike stolen, and to try and fill that void, I picked up a 2015 Specialized Crosstrail (I'm riding more paved and gravel trails these days, my full-on mountain bike days are over!). The bike was in very good physical condition, apparently very lightly used. I was unable to ride before purchase, but it looked good and the price was right, and as an engineer that's handled most of my own bike mechanical work over many years of riding, I jumped on it anyway.

For the most part the issues were minor and easily addressed, but as I started taking the bike on some of the steeper trails in my area, more and more problems with the drive train began. It's ostensibly a 3X9 arrangement, which in my experience is a negative, since getting the set up so that the entire rear gear set can be accessed by the 3 front gears is touchy and in my experieince I usually ended up chasing my tail with adjustments, especially as the mechanism aged. I eventually had this problem on my yeti that started with a 2X8, or something like that. At the time, I decided to add an early SRAM 1X11, which I installed myself, and it made the bike much more rideable, albeit in less hilly terrain.

Sorry for the long windup, but I'm considering replacing the 3X9 with a new SRAM 1X14 drivetrain, but I'm worried that the 14-gear stack is going to end up too big to fit where the Shimano 8 gear rear stack was. It appears that the latest SRAM gear stack has thinner gears than the older Shimano, but I'm wondering what other folks experience has been. I've been trolling YouTube to try and get some info in this regard, but so far, no success.

Thanks in advance for any helpful information!

Jack

Remove the rear wheel and cassette from the freehub and measure the FH's spline length. Then do some homework on how much spline is needed for your conversion idea. If you can't figure this out try a LBS and consider buying from them. Andy

considering that 14 gear cassette is not even available On SRAM's Site... id bet it won't be fitting your HG shimano style hub.

SRAM does make a 13 cassette... but it only works on an XDR freehub hub, bub....finding that style hub in anything other than thru-axle will be tricky... they do make a road hub in QR, but i'm not sure of it's OLD width...

i'd think going with a properly selected 10 sp. setup may be a better option... i've recently fought a 12sp. 11-50 eagle SRAM cassette that wants to jam up the chain if it got backpedaled a rotation or so when shifted to the 1-2-3 or 11-12 gears., no matter where i placed the chainline... the flat top chain got #3 working much better, and 11 quit jamming too, but the other three still jammed.
that bike arrived here with a KMC 12sp. chain installed, and was NOT happy at all.

3x9 is what I consider the sweet spot.
Just don't use the extreme cross chained gears.
No Big ring with 1 & maybe 2 and no Small ring with 9 & maybe 8.
You should have enough overlap between ranges to do this.
Maybe a rare occurrence when you get caught "napping" and don't have time to execute a double shift.

I have around a dozen bikes (all good) with cassette counts from 7 to 12. Today I was using an Emonda SLR with a double shifting with Dura-Ace Di2, which operates very well indeed.

However, the bike I use the most is a 1991 steel MTB with 26" wheels, no suspension and a 3 x 7 Shimano drivetrain with the legendary XT thumb shifters. I've also been spending a lot of time on a Lemond with a 3 x 9 Campagnolo drivetrain. Also excellent.

It's all good. Tune what you have, and do the usual cable and housing replacements, new chain, replace worn cassette cogs etc. 90% of the problems we see at our Co-op are simple maintenance and solvable by replacing consumables, resulting in drivetrain performance that is good as new. Or often better.

Before anything, you should determine what gear range you need, how to calculate it using the gear-calculator programs online. This measurement will be independent of wheel size, but will vary with the wheel size, the program will take that into account. I think in "gear-inches", but the other units are fine too, you just need something for apples-to-apples comparisons.

For example, my 1X folder with 20"/406 wheels lowest gear was about 33 gear inches, and I needed about 21 G.I. for the hills here. I would have liked 3X gearing but that wouldn't package on the folder, so I went with 2X, with a 50/34 hollow spindle crank with external bearings (LOVE it, many benefits), and that gives me a range of 21-85 gear inches, about 400% range. 85 G.I. is just enough to pedal down mild grades, I don't need higher, I'll just coast.

You need to determine your needed lowest and highest gears. Then you can see what components will work. With your bigger wheels than me, high gear won't be a problem; Getting the lowest gear you need will be the primary issue; You can get it with a big pie-plate low cog on a 1X cassette (limitation will be the rear derailleur, standard ones are max 34T cog and these cassettes and derailleurs are dirt cheap to buy, but newer 1X RDs can handle a much larger low cog and total cassette range), or a granny low on a triple crank.

To find your needed gear range, find the lowest gear you need on your bike, then enter the tire size, chainring teeth, and cog teeth into gear calc, and it will provide your gear inches or metric units. do the same with your needed highest gear. Once done...

Now, using gear calc, you can play with specs for chainrings and cogs, to look at all the possibilities, at your fingertipes, in seconds, to figure out what you need. The gear calc program on Sheldon Brown website is fairly simple. The one on gear-calculator.com is more sophisticated, with a graphical interface, you can slide the chainrings and cogs along a scale, to change results quicker and easier.

So go get your data on needed gearing, then we can look at options.

Here's a 10-speed, 11-50T cogset on a standard HG hub carrier body playing marvelously nice with the Shimano Deore M6000-GS RD.


The Shimano SLX M7000-GS and XT M8000-GS RD will span the Deore M6100 11-speed, 11-51T cogset well too. Unless you need greater than 464% gearing range or really closely spaced gears, no need go beyond 1x and 11-speed.

This is new. On the Folding Bikes channel you've always pooh-poohed the simpler, lighter, less expensive 1X drivetrain by saying that it doesn't give you sufficient gearing range to pedal downhill. But now, you are apparently singing a different tune. To be clear, a 1x setup with a 11-46T cogset -- one that I've shown to work well in real practice both around town and on several extended overseas tours -- returns 418% gearing range, more than your stated target. So, which one is it? Time to come clean and stop flip-flopping. Does a 1x drivetrain with a 11-46T cogset provide sufficient or insufficient gearing range for you?

Oh I've long since acknowledged to others here (with attribution to you) that your setup is simpler and cheaper to implement, especially with the interference issues requiring finessing with a large seat tube, thick FD adapter, and thick FD cage rollover lip. My memory may be off, I had recalled you successfully doing up to 11-42 cassette, hence my saying "almost" 400%, I had forgotten that in the past year (or more) you've gone beyond 42.

I still like my 2X setup, but I've also said in recent months that if I need to mod my other 406 folders, it makes sense to go wide 1X. It wouldn't be if the FD setup wasn't so much of a hassle, because the cranks they come with are heavy junk swaged steel chainring onto aluminum arm, and the hollow crank with external bearings upgrade is SO nice, and same cost for 1X or 2X. However, note, these are old Dahon 7 speeds on 130mm OLD rear, so if the wide 1X needs an 8 speed freehub body, that's an additional expense. Most other folks on here with newer folders with 8 speed, won't have that worry:

2X (keeping 11-30 or 11-32 stock cassette):
- crank and external BB bearings
- FD adapter
- FD (modified by grinding off some inboard cage lip where interferes at FD adapter)
- front shifter
- GS (mid) length RD, claw mount if old Dahon frame, (cheap Tourney or Altus works fine)
- (longer) chain
- cables and housing

(wider) 1X: (NOTE: These old Dahons are all 7 speed and don't have 8 speed freehub bodies, and are 130mm OLD rear): So:
- possible need for new freehub body
- wide 1X cassette
- (new) rear shifter
- (new) rear derailleur, Deore or other better quality
- (longer) chain
- I could technically stay with the junky OEM Dahon crank, but it's junky and heavy, so then add a hollow crank with bearings.

So, not the savings for 1X, upgrading an older folder with short freehub body and steel crank. But for newer folders, 1X seems the way to go.

Oh and pedaling downhill, I've always thought that 85 gear inches is enough for me. The only reason I'd like higher is to (lightly) pedal down really long descents, as it saves wear on the ratchet and tiny bearings in the freehub body, but I always try to drip in some lube whenever the cassette is off for cleaning. That's a minor concern.

EDIT: Back during my race bike days, if I got the bug for small wheelers like now, I'd need higher gears. Back then, it would need to be a monster chainring, to avoid an IGH. On a Moulton AM space frame.

Have just skimmed the thread, but here goes.

I've been using a 3X9 6503 Ultegra set up since new all original except I replaced the R shifter long ago about 12 years ago. I used it for over a decade and then transfered it to a cross bike I made into a "gravel" bike, and then gave that bike to a friend. I still ride it when I visit. I consider it an excellent system in terms of reliability and versitility.

I've never considered it essential, or even with the design intention of any 3X system to have noise free access to all of the sprockets with all three chain rings. Just not a practical goal or essential need. Does anyone really expect that?

I always was successful at adjusting the middle ring to work with all 9 sprockets, and the large and small ring to work well with 7 or even 8 of them. That's what the front shifter is for! But I also found the middle ring with 9 sprockets to be effectively a good 1X system for a large majority of any ride I was on.

Carefully adjust your front and rear shifting and keep the 3X9. Aside from the hub compatibility questions mentioned above, and the expense of replacing so many expensive parts to switch to a 1x or 2x system that meets your needs, the 3X9 is a great system and worth making work satisfactorily.

If you need lower gears than what you have, simply get a 9 speed MTB cassette with the low gear you need and get an old Deore XT 8 or 9 speed RD off of EBay - the 8 or 9 speed versions are fully compatible with 8, 9 or 10 speed road shifters (the 10 speed MTB RD is not). My 3X9 group looks weird to anyone who notices or cares (very few), but great range: 52/39/30 and 11-34. Flawless shifting within the common sense limits of a 3X system.

I was already with 1x and 11-42T in 2018.

Thanks. I joined here in 2017 but didn't use the site at all until I discovered the folding bike group in perhaps 2022/3? But a lot of your posts would date back earlier on threads. I read deep, it was clear you knew your stuff.

I'm good at careful measuring and finding/modifying stuff to fit (like for my 2X conversion), but don't have the component knowledge you have. Before I discovered the folding bike group, I saw threads in general, asking "can you do lower/wider gearing on a Dahon folder?" and the answer was always "No." Nothing about multi chainrings, nothing about wider range cassettes, just "No." Which is why I had to figure out everything solo when I did my 2X. But once I saw the folder group, HAH, I got sucked in deep. I would have been there years earlier, although still seldom, as back then I had no home internet, was only using the library until 2022.

I even did a detailed writeup on my 2X conversion with the intention to post, but while editing, I got deep in the folder group and realized, "Nah, these folks are way ahead of me." I think I explained it to a few people who were looking to do exactly what I did, but later on I said that your wide 1X conversion is easier and cheaper.

This is basically it

Triples can be a little finicky to set up but no one needs to use all 27 combinations.

and I hope you were trawling Youtube rather than trolling it 😁