Smitty2k1

I've got a Jamis Aurora touring bike that I've been riding and modifying for a number of years. It has been on many an overnight camping trip but is currently hauling my 40 pound kid and commuting gear.

It came with a triple 9 speed setup from the factory using a mix of FSA crankset, Shimano Tiagra up front, and Shimano XT in the rear. Parts have been replaced over the years and I converted it to a flat bar build and 650b with wide tires and this is what it is currently equipped with:

Shimano 9 speed 11-34 cassette
Shimano XT RD-M772 rear derailluer
Shimano Tiagra 50/39/30 FC-4503 crankset
Shimano Tiagra FD-4503 front derailluer
Shimano XTR SL-M970 3x9 shifters

I'm wondering how I can get some lower gearing without sacrificing the high end too much. I see there are many triple cranksets that have a wider range than 20T (e.g. 24T here: https://velo-orange.com/products/gra...kset-24x34x48t) but wondering if my rear derailluer could handle that and if I would need a new FD too. Alternatively if people have had any success with 36T cassettes with the XT rear derailluer.

cyccommute 

The rear derailer might struggle work with a 36 tooth cog. A Wolf Tooth Road Link would help if it doesn’t.

As to the crank, you can fit a 24 tooth inner ring on your current crank as it has a 74mm BCD. If you went with a mountain bike crank, you can easily get a 22 tooth inner ring. A Shimano Hollowtech II crank will even work with your current bearing. You’ll have to go to the used market which probably means hunting around on Ebay. Fortunately, they aren’t rare nor terribly expensive. A 44/32/22 crank may not have the same high as you have now but you can replace the rings with a 46 or 48 if you want to.

One caveat on the mountain crank, it has a wider chain line than your Tiagra. The front derailer won’t be able to move far enough outboard to shift properly. You can move the spacers on the drive side over to the nondrive side and it will shift just fine. I have this set up on a couple of road bikes. Or, since you have mountain shifters to begin with, you could just use a mountain front derailer. Another caveat on the front derailer if you go with a mountain one, don’t go with the highest end. Shimano high end front derailers…road and mountain…are too clever. That makes them sensitive to set up and they tend not to have as wide a range of use as their cheaper brethren. LX and below are far more forgiving on set up and use than the higher end models.

timdow

I used to have a Y2K Jamis Aurora that I swapped cranksets on. I put a mountain Sram S600 22/32/42 on it. It was a PITA to get the chain-line and shifting right on it. I had to also change the bottom bracket and I believe the front derailleur (been a long time).

As stated above, you can simply change the little ring down to as low as 24T. However, you will have a big jump from 24T to 39T, and are limited to smallest middle ring of 38T. Given that, I would personally would go with a 26T little ring. If running either a 24T or 26T it would be prudent to use a "chain keeper" to prevent the chain from dropping off during shifts.

The ring change is fairly inexpensive, so worth a try. If it does not work out well, you could do a switch to a "trekking" crankset which is 100/74 BCD. This would normally have something like 26/36/48 gearing, and could better support a 24T if needed. The offset of a trekking crankset will be closer or the same as the one you have, but this should be verified so you know that the current BB and shifter will work.

Tourist in MSN

If you can get by with just a smaller granny gear by changing the 30 tooth chain ring for a 24T ring as was suggested above by Cyccomute, I suggest you do that. It is low budget and gives you much lower gearing.

For almost two decades I have been using a road triple that came with a 30T granny gear that I changed out to a 24T on my two derailleur touring bikes.

You might find that you have too much chain length when you are using the smallest chainring and the smallest sprockets in back, a rear derailleur can only take up so much slack. But you should not be using your couple smallest sprockets in back with a small chainring anyway because that is badly cross chained. For about a decade I was having to avoid a couple gears because my rear derailleur did not take up all the slack, no problem as those were not must-have gears anyway.

tyrion

I just got a Shimano XT 44-32-22 (9 speed) crankset and replaced the 44 with a 48 and the 32 with a 36 so now I have a 48-36-22 crank. Total cost about $150 (I am a bargain hunter).

tcs

OP - schweet basketpacker.

csport

Same thing. Started from a 48-36-26 and replaced 26 with a 22. Moved one spacer to the NDS. Running it with Sora 3503 brifters, old 9 speed 105 triple FD and Microshift M46 RD. I run an 11-30 cassette, but this RD is rated for a 36t max cog.

PDKL45

I was running 9 speed Sora with the same 30-39-50 front triple and a Deore RD of the same vintage as your XT, an M590 IIRC. Cassette was 12-36 and with that derailleur, it was plug and play, no roadlink necessary. Even if it is over total capacity by a tooth or two, the RD should be just fine.

For smaller granny gears, Specialite TA makes smaller rings with the correct 74 BCD for road cranks (pre 4700 Tiagra and old-school Sora). I looked into it, but replacing three road rings with Specialites TA rings was going to cost more than a new crankset.

If you're after a trekking crankset, though, Shimano trekking is going the way of the dodo. I'd get in ASAP to pick up a 26-36-48 NOS Alivio triple crankset, because it's being replaced by CUES. But also check CUES out, because there's a new adventure double that's something like 44-26, that, coupled with the right wide range cassette, should give you a really wide spread of gears. Aftermarket CUES available retail is a while off yet, though, I guess.

AeroGut

I have that exact Tiagra crank and FD with the inner ring swapped to 26t and have had no problems shifting. I put a chain catcher on the seat tube just in case but I don’t think that’s necessary. I also have XT rear derailleur but cassette is narrower range than yours.

cyccommute 

[QUOTE=PDKL45;22845769If you're after a trekking crankset, though, Shimano trekking is going the way of the dodo. I'd get in ASAP to pick up a 26-36-48 NOS Alivio triple crankset, because it's being replaced by CUES. But also check CUES out, because there's a new adventure double that's something like 44-26, that, coupled with the right wide range cassette, should give you a really wide spread of gears. Aftermarket CUES available retail is a while off yet, though, I guess.[/QUOTE]

There are lots of really good triples around on the used market so that’s a good place to start if you really want something with lower gears that’s a road triple. That said, the wide range doubles are cranks for drivetrains designed by idiots. They really don’t offer that low of a gear and they don’t offer a good shift pattern. Using Gear Calculator, it’s easy to see the hassle of upshifts and downshifts using the wide double concept. If you are traveling along in the middle of the range in a 24 tooth gear and come to a hill where you need to shift down, the jump is large. Increasing rpm from 90 to around 200 won’t keep up with the difference so you either spin like a mad duck or you let the bike slow or upshift 3 gears. Meanwhile you are losing momentum that will carry you up the hill just a little bit further. If you upshift and kind of want to keep the same cadence, you have to downshift 2 or 3 gears. All of this while trying to pilot your loaded touring bike up (or down) a hill.

With a triple, a single shift puts you into about the right gear without all the fiddling. Notice also that the triple with a 22 tooth gear gives about the same low gear with narrower range rear cassette. If the 11-42 is to be used with the triple, the low gear is even lower which many will find to be a plus.

Tourist in MSN

Yup, every time I shift my compact double (50/34) on my road bike that has a 10 speed cassette in back, I make two or three shifts in back to compensate for the shift up front.

A friend of mine got a new 11 speed bike, he almost never rides it, usually rides his older bike for the same reason.

djb

I too have a bike with a 50/39/30 that I improvised to a 26t , but I find the 39t mid ring too big for loaded riding a lot of the time.
That 48/34/24 would be a fantastic chainring choice that would work out great for touring/heavy bike times, as well as unloaded.
I still find a 48t to be overkill, but overall that would be a great setup.
I have a 700 bike with a 42/34/24 and find it to be really versatile. The 34t covers so much of your real life speeds, majority in fact, and a 24t inner is great.
My touring bike has a MTB triple, 44/32/22 and it works great for heavy load and mountains.

irc

". I see there are many triple cranksets that have a wider range than 20T (e.g. 24T here: https://velo-orange.com/products/gra...kset-24x34x48t) but wondering if my rear derailluer could handle that"

The chain wrap spec for the long cage version of the RD-M772 is 45. So 11-34 uses up 23. Leaving a max of 22 difference at the front. So your Velo Orange cranks are theoretically 2t too much. That said you shouldn't be running the 48t front with the 34 rear. to avoid excessive cross chaining only the inner or middle rings should be using the 30 or 34t rear.

So I think the M772 would work. You would need to make sure the chain was long enough to run 48-34 in case you shifted there by mistake. The result of that would be that the deraileur might not take up all the slack if you ended up in the 24 front and 11 rear. Another combination you shouldn't be using.

All that said - there is supposedly a bit of leeway in Shimano specs. So as you are only 2t out it might work at both extremes. but as you shouldn't be using either extreme you could go for it.

That said - how much top end do you need. I run a Deore 22-32-42 triple on my tourer which was enough for a sustained 28mph with a big tailwind. Or there are MTB triple with a 44t big ring. Cheap. Though you would might need a new front deraileur.

https://www.amazon.co.uk/Shimano-Ace...dp/B00DY1TTIG/

Jeff Neese

I have two bikes with a Sugino XD600, which are 26-36-46. You would probably need to replace the BB. What's the chainline spec on your bike? It's probably 45mm, but it would be good to know for sure if you're thinking about swapping cranksets.

If you can accomplish what you want by just swapping chainrings as others have suggested, that's probably the way to go.

Jeff Neese

Of course we should all know to avoid crosschaining, but I think it's a very bad practice to have a gear combination on your bike that literally doesn't work and could cause damage if mistakenly used. Even if you don't use them while riding, every gear combination should work on the stand. That's my practice, anyway. I shift through all rear sprockets, using all front chainrings, and everything has to work smoothly. I don't give myself an opportunity to make a catastrophic mistake while on the road.

djb

all this talk about some of us using mtb triples or whatever with a 42 or 44t big ring ends up coming back to how much top gear do you really need?
if you have never looked at gearing charts that give a black and white answer of the range of your gearing, do so. I'm familiar with the term "gear inches", its the one I learned about all the years ago when I was in your boots now, trying to get lower gearing on my touring bike, and the friendly guys at my LBS explained this stuff to me and showed me some charts.

there as always been a rough take on gear inches for touring, that you want about 20-100 gear inches, and even with way better drivetrain options now, this rough range is a good one to keep in mind.

as for top gear and real life speeds and expectations, here are some examples of bikes I ride:

my lighter bike that I tend to ride faster, 26-112 gear inches, I can spin it out to 70kph on hills
my commuter bike, 23-104 g.i. Easily spin up to about 50kph
heavier touring bike, with a super low 16.7-103 g.i. that can get me and all my crap up steep steep hills all day long but still able to spin out to about 50kph

but really, how often on any of these bikes do the conditions allow me to hold anywhere near 40kph for any reasonable amount of time--hardly ever-- we are talking about really long downhills (rare, and lets face it, if touring, you are wasting energy to try to hold a much faster speed, and anyway, any headwind will slow your slow-ass touring bike with panniers down like crazy) or the very rare big tailwind day. Even with tailwinds, holding 30, 35, 40kph is still completely doable.

so all of this is to question how high a top gear you really need. Yes, riding unloaded its different, but even then, your bike is not a 17lb racer, its most likely in that very average high 20 or 30lb bike.

I still think that velo orange crank is a real nice one, really nice for the vast majority of riding. Get a good square taper bb and you'll be set for years and years.

let us know what you decide

Smitty2k1

Thanks for the replies everyone. Lots to digest here. Honestly I probably would be happy with a 28T small ring instead of the 30T small ring. If probably also be ok dropping to a 48T big ring instead of the 50T I've got now.

Seems my best bet is to try the 28T small ring swap and see how shifting works. Wondering if I need a new FD since Shimano says this is designed for a 20T difference specifically at 30/39/50T?

cyccommute 

Probably not. Shimano is very conservative on their front derailer ranges. I’m running 24 tooth difference now on my touring bike and have run up to 28 tooth differences on the same derailer. They work just fine. Try the new gearing first with the current derailer before you buy a different one. If it doesn’t work then get a new derailer but don’t run out and buy one before you try the new gears.

djb

from my experience, its not worth just dropping 2 teeth to a 28. When I changed my 50/39/30 to a 50/39/26 I knew if I was going to go through with the hassle of changing it, I might as well drop 4 teeth. I sourced the 26t at actual bike stores, same thing when I did the same thing for a friend of mine with the same crankset, but you will have to look online to find chainrings , so heck, go to 26.
My front derailleur handled the 26 from 30 with absolutely no issues, didnt have to touch a thing. I did however have to improvise a bit with putting some spacers inbetween the crankarms and the 26t, as the original 30t had a shape that put the actual chainring out a bit towards the frame, so I used washers I had , maybe a mm thick, to move it out just enough to work well.

like with all stuff in life, sometimes you have to improvise, and a bike store might tell you it cant be done, but in my case, it was fairly easy.

I did the chainring change myself, but who knows, you maybe have never removed crankarms or chainrings before, so you'll be back to getting a store employee to do it. Will really depend on if they are willing to do it. Often Ive found that if something isnt textbook, they wont want to do it because they need to cover themselves for fudging or improvising, and I get that.

the devil is in the details sometimes, thats life.

and then there is how much you want to spend. But on the money side, dont waste your time and money to only change 2t. And being 2t over the official limit is not a problem, but source that opinion elsewhere, dont believe me.

afrowheels

I'm not especially good at gearing calculations but some of the answers to this previous thread might also be helpful:
https://www.bikeforums.net/touring/1...ake-sense.html

I switched to a 3x9 system, with 48-36-24 at the front and 11-34 at the rear (https://www.bikeforums.net/22674934-post44.html) and I have been happy with the range for a heavily loaded touring bike doing some serious climbing and descents. Could have used one gear lower but so it goes.

The one thing that I was warned about by the mechanic who installed the new components was that there would be a lot of slack in the chain when you are on the largest front cog and smallest rear one. In theory you would not want to do that but in practice you might, so it's something to watch out for. And I presume if the range is wider it would just exacerbate the issue.

I have also noticed the chain slipping off at times when shifting down from the bottom of the second gear range to the first but not sure if that's a function of the combination or something else.

Yan 

50 front 11 rear is 37 mph at 100 leg revolutions per second. I'd give a second thought to whether you're actually capable of riding that fast. A fantasy top gear that you're not fit enough to use is just dead weight.

Forgive me if you happen to be an elite athlete. In that case ignore me.

tyrion

If I have a tailwind or a downhill, I like putting it in the highest gear and getting a little more speed. You don't need to be an elite athlete to enjoy the higher gearing.

Yan 

You're right, but 37 mph? Are you just saying that vaguely or have you actually observed this speed on your speedometer? What's the exact top gear on your bike?

Pro riders in the Tour de France travel at around 25-28 mph on flat ground, inside pelotons. Here's what it looks like in first person with Caleb Ewan (multiple Tour de France stage wins). At one point he's pushing out 800 watts.


37 mph is another 30% faster than this. Average guy on a touring bike is going to need a massive mountain descent to hit that speed. How many times a year are you hitting this speed? At that point maybe just take a break and coast.

Drop the large chainring to a 42t so you can use a 24t small chainring, which is something that you would actually use.

djb

I agree, but lets be realistic. how many times can you do that?

and don't get me wrong, I like going fast much more than the average joe, and probably have gone as fast or faster than most of you here on two wheels, but again....touring.....it aint gonna happen that often and all the top speed runs I have done on non motorized two wheels, 80, 90+kph, I was waaaaaay past my gearing anyway, so not pedalling.
On motorcycle, well over 260kph.

compare that to all the times touring when we are busting our lungs and knees and wishing we had lower gears!
Countless times.
Heck, I've even been wishing for lower gears with my sub 17 gear inch low and my heart about to go pop on stupidly steep ramps, having to stop and not have a cardiac event--and that was after riding in a lot of mountains for two months straight!

tyrion

Maybe 3 times a week.