robo

My wife has a cyclocross bike she uses for weekend rides and light touring. It came with fairly standard 'cross gearing of 36/46 in the front and a 10 speed 11-26 cassette in the rear. With 28mm tires and 170mm cranks, this gives a minimum gain ratio of 2.8, and this is proving unridable for any serious hills when the bike is loaded with gear...

I'm new to thinking much about gearing (I've been lucky and have been happy with the stock gearing on my bikes), and was looking for some advice on getting some better gearing on her bike, ideally while replacing a minimum of parts or incurring minimum upgrade cost.

Here are the relevant bits:

Crank: FSA Gossamer double, 110BCD, 170mm arms
Chainrings: FSA N10, 36/46 tooth
Cassette: SRAM PG1070, 11-26 tooth (10 speed)
Derailleurs: SRAM Rival, normal cage rear
Shifters: SRAM Rival brifters

One idea would be to go from a double to a triple, but this seems like an expensive option, requiring a whole new crank and front SRAM Rival brifter (and front derailleur?)

The next idea was to put on a wide ratio cassette, but I realized that this would also require replacing the rear derailleur, as (AFAIK) the SRAM Rival unit she has maxes out at 28 teeth.

Another option might be to get a smaller inner chainring, although I'm not sure how much difference this will make.

Any advice here? What would be the smartest way to go? I do like the idea of making the changes at the cassette end of things, as this could let her have two rear wheels, one for regular riding and a sturdier one for touring, which could be swapped out with a minimum of fuss. Would a 12-32 (or even 12-36) cassette and a SRAM mountain derailleur be the solution?

I'd be interested to hear from anyone who has done this or has some ideas

scotton

I would go for the megarange cassette and a cheap MTB derailleur. I have this setup on two bikes (one is a 1x9) and I've been happy. I run Shimano, so I went with an LX RD. Not sure what the equivalent SRAM RD would be, but you should be able to get it done for around $100 - $150.

davidad

Bite the bullet and go for the triple. You need low gears down in the 16 to 20 inch range. https://www.jbarrm.com/cycal/cycal.html

bud16415

The gear calculator I find I like best is found here.
https://home.earthlink.net/~mike.sherman/shift.html

It’s very hard to recommend touring gearing without knowing the worst case climbs, the riders level of conditioning and the expected weight to be carried. Many are touring with doubles and when you start analyzing things as I did for me a triple was necessary and then I discover I really had little use for the big ring. Some run a triple with the large ring removed and replaced with a chain guard. Chances are going to a triple will require a new BB as well to allow room for the granny gear. If you want to have a bike that serves dual use by trading the rear wheel and crank from time to time that might not be that hard to do. Getting into switching out FD and RD and BB along with crank and rear wheel would seem to be more work than getting a tour specific bike. I found it wasn’t that hard to go the opposite way though and my tour bike is very much to my liking as my daily rider.

I personally didn’t like the mega range cassettes although they are much better than not having a bail out gear for climbing. My reasoning for this is a couple things. Around here the climbs are rolling and even though there might be some point I need a 20 gear inch range I don’t want to be stuck with just one low gear. The option would be a front shift or a back shift. The front shift is a hard one to make off a small granny gear and should be a coasting soft shift. The jump in the back with a mega range was also a very big step and nothing like cascading to a few more moderate steps. So what I would end up doing with the mega range was spinning out and then having to coast until I reached that real slow speed to start in again. I have always liked to build speed when I can on rolling hills and let some momentum help me with the next rise. Along with that if you feel she needs say 20 GI as an absolute lowest gear. In my case I have my lowest at 18 GI but I have option for 20, 23, 27, 31, 36, or even 40 before I worry about cross chaining all off the granny gear.

I run the 12-36 cassette and have been quite happy with it.

Just as another suggestion and I don’t know if this would help you or not but on my Cannondale road bike I wanted to get a better climbing setup to use around here. I took a cheap mountain triple and removed the granny giving me a 44, 32 double with the 32 lined up on the center of the cassette (min cross chain) the 44 was only needed on the 3 smallest cogs so no cross chaining there as well. All I had to do was lower my FD as far as it would go and it worked great. In my case I left the road cassette alone and RD because I wasn’t touring loaded on this bike. But I think if I had put something like the 12-36 on the back it would have been pretty respectable for loaded touring. It would only be a half hour switch if I wanted to swap rear wheel and put the road crank back on with its correct length chain.

bradtx

robo, A 34T inner chainring and a cassette with a 28T low gear will improve gear inches by about 10%, which can be noticed. Will it be enough? Only your wife can determine that.

Brad

HillRider

If you fit a triple crank, which is by far the most efective way to get a truly low gear, you have to abandon SRAM road brifters. None of them are compatible with a triple crank. Shimano is the only maker of triple compatible brifters and triple cranks these days. Yeah, Campy brifters will work with a triple crank but that opens up a whole new world of compatibility issues.

Getting the gearing your wife needs is going to be fairly expensive no matter how you go about it. The N+1 approach by buying new suitable touring bike might be just as attractive, particularly if you canfind a good used one the correct size.

bud16415

A couple more thoughts.

If you go with the N+1 idea and hope to get it done for about what it might cost to upgrade the cross bike you will be looking at something used. I don’t know what bikes are selling for in England or what there is in the market place but on this side of the pond used touring setups are few and far between. When I found one in my frame size I snatched it right up. Prior to finding a touring bike I went with what is much easier to find here and that is an older mid 80’s mountain bike 26” heavy duty wheels, no suspension, etc. that only require substituting road tires and changing the straight bars to something more touring friendly like north road or trekking bars. I have an old KHS I did for about $150 including cost of the bike. This method builds you a really bullet proof mountain goat of a touring bike.

Another plus for the N+1 is the racks, fenders and all that stuff won’t be on her fun bike weighing it down.


One thing you can do with her bike as it is now when loaded is using the gears she has now, try and figure out two things. First what she would feel is the tallest gear she will ever need. Record what gear she’s in and put her current bikes gears into a calculator. The next thing to have her think about is what gear would she like for her middle/ middle gear given a triple crank. Have her think about if she was in that gear and had 5 higher and five lower what that gear inch would be. Once you know those two starting points you can do a lot of “what if’s” in the calculator with all the different ideas people will give you. Most people don’t have any idea what a 20 GI or lower gear feels like. Find a mountain bike to test ride with a super low granny and have her spin it up in that low gear just to have her get the feel for that and her thoughts. Parts are expensive enough and if you don’t do your own work more cost, experimenting with what you already have and playing with a calculator can save you a lot.

bud16415

HillRider
You are much more knowledgeable than I on what could work with what.

Would it be possible to say use the inner two rings of a mountain crank even removing the big ring in a case like this and get the SRAM road brifters to work with say a 32, 22 crank as a double?

With the 32 centered on say an 11-32 cassette. Giving a 26 to 77 GI range on the 32 and a low range on the granny starting at 18 GI.

fietsbob

may get off for less.. buy a friction bar end shifter for the triple front chain ring.
re install the shift cable to it , instead of the brifter..

then you still will use it as a brake lever.

ThermionicScott 

How "light" is your light touring? I calculate more of a 13% difference by going to a 34/28 low, which would be the cheapest option. Using an MTB rear derailleur and a 12-36 cassette like Bud's (who needs an 11T on the top, anyway?) drops your low gear by 38% (to 26.7") without touching the front setup at all.

pdlamb

You might be able to get a triple, and change the front brifter to a Campagnolo. Depends on how much your wife values consistent "feel" on loft and right sides.

Thinking outside the box? What's a box?

cale

Robo, I would replace the rear derailleur with a Sram Apex mid-cage, the cogset with 12-32, and a new chain. This should offer the low gearing she needs for light touring and reduce the expense and complexity of the revised drivetrain.

robo

Thanks for the responses. I hadn't realized that SRAM didn't even make a triple road shifter - that's kind of a bummer, although not my first choice anyhow. Somehow I don't think she'll like the idea of a bar end shifter replacing her brifter, as was suggested by fietsbob.

I think I'm going to have to see what gear range my bike has, to get an idea what the options would feel like on hers. It's hard to get a sense of what 28% lower (or whatever) means in actual use.

As for what 'light touring' means, it means short trips (sometimes just overnighters) with rear panniers carrying a sleeping bag and pad, some clothes, alcohol stove, pots, and food, and half a tent across the top of the panniers. Not trekking across Africa loaded, but more than just credit card touring. She hurt her knees quite a bit on our last trip trying to pedal up some steep hills with her tall gearing (she couldn't walk properly for 24 hours due to knee pain after we got home), while I was able to drop into the granny gear and spin away.

ThermionicScott 

Ouch! Cycling gets to be less fun in a hurry once you have an injury like that.

Maybe this illustration will help, since I love "running the numbers" on these things: switching from an 11-26T cassette to a 12-36T gives the same low gear as adding a 26T granny chainring to her current setup. Either way, that's a serious low gear that should let her spin up most hills.

JohnDThompson 

If you can't spring for the triple (which would involve replacing the crank, bottom bracket, and rear derailleur at a minimum), go for a wider range cassette and rear derailleur. Your 110mm BCD crank will only accept chainrings down to 34T, which is only trivially lower than the 36T she presently has.

cpach

Another crazy option that should work would be be a 2x10 mountain bike crankset with 28/42 rings or similar. I'm unsure if this would work at all with the existing front derailleur, but the cable pull ratios for 10sp Sram stuff is the same for mountain and road.

By far the easiest change would be a wide range cassette and new rear derailleur. You could also use a Sram 10sp mountain derailleur and get as big as a 36t cog.

rdtompki

A Rival mid-cage RD will handle up to 32t (my single) and an X.9 RD will handle 36t (our tandem). I'd go with a 34t small chainring up front and an X.9 or X.7 RD which will give you a lot of flexibility. I haven't done the calculations, but the combination of the two will give you significantly lower gearing than what your wife has now without changing out the shifters. Yes, some of the gaps in a 12-36 or 11-36 are somewhat large, but four touring I don't think that is any sort of an issue versus the benefit.

Campy shifters, at least the Chorus 10-spd on my two bikes, have excellent compatibility with the new SRAM Exact Actuation RD, but that's a fairly expensive way to go in combination with changing to a triple.

robo

Thanks for the further replies guys.

So it looks like SRAM X9 is the equivalent MTB group to SRAM Rival. I guess a medium cage X9 rear would be about right (like this), along with a 12-36 cassette. I plugged the numbers into Sheldon's gear calculator, comparing with my bike (12-25 9-speed cassette, 26-36-46 rings, 650b wheels), and it appears that my lowest gain ratio is about 2.0. If she gets a 12-36 cassette, her lowest gain ratio will be 2.0 as well, even without changing out the small chainring. I've sometimes wished for a little lower end when tired and loaded on a steep grind, but it's certainly OK. Much steeper and pushing the bike starts to be preferable anyway.

Would I be correct in assuming that Shimano and SRAM 10 speed cassettes are interchangeable, and that if we do go for the smaller chainring, since it's the smallest ring, any plain chainring will do?

cpach

Yes, Shimano and Sram cassettes and chainrings are interchangeable.

rdtompki

If you go with the SRAM MTB RD I'd be inclined to go long cage in case you ever put a triple up front, but check the wrap capacity of the medium cage RD and do what works best for you.