Melville54321

Hello there, I have some questions about the least expensive/most practical way to get some smaller gears on my bike for loaded touring. It's not absolutely vital, but it would be very nice as I'm planning on taking this bike through Central Asia in the spring, and I believe my knees would thank me. I've got some basic bike maintenance skills (and I think YouTube is wonderful), but as far as understanding the compatibility involved with switching out drivetrain components, I'm still learning, and thus I'm turning to the internets for help and advice.

The bike in question is a 2011 (I believe...it's second hand) Surly Long Haul Trucker. Right now it's got more of a road/lighter touring set-up with 105 components. 105 compact double crankset (50/34) on the front with a 105 derailleur, and a 105 11-speed 11/34 cog on the back with a 105 derailleur. Shifters are 105 5800 11-speed shifters. Wheels are also 26" which buys me a few more gear inches.

It seems to me that the easiest fix would be getting a smaller little-ring on the crank. Maybe something with 28 or 30 teeth?

I'll most likely be doing the maintenance myself...so simpler fixes are better. I've fallen down the google-researching rabbit-hole, so I realize there are more than several options. I prefer STI shifters and have drop handlebars, so I'm not sure that throwing mtb components on it would be my top choice. Two of the more straightforward solutions seem to be.

a) adding a triple...which as I understand would probably also involve a new bottom bracket, front derraileur, and (left) shifter (anything else?)

Could I also add a triple without changing out my derailleur and left shifter, and simply only use the smaller two rings and just pretend the biggest ring doesn't exist? I know it's unconventional, but I'd be willing to try it if it would work...

b) a compact plus crank such as SUGINO, store.interlocracing.com/irddewicorod.html, or Grand Cru 50.4 BCD Crankset MK II - Cranksets - Components. I see that Sugino makes one compatible with an 11-speed, but it's horribly expensive. I can't really figure out if the other ones are also compatible (They're also not cheap, but better than Sugino's), but being just one part if it would be less than replacing several parts I'd be willing to consider it.

I'm also in Greece right now (I'll be in Turkey next month...and I don't speak either of these languages) so rooting around for cheap second-hand parts may be bit more complicated than if I were in the States, and I don't exactly have a trusted LBS that I can just pop into...so my options for parts will probably be ordering them online or wandering into a bike shop and hoping for the best.

Anyone that has any advice or better ideas...they would be much appreciated!

HillRider

You can't fit a significantly smaller chainring to your current 105 crank. It's 110 mm bolt circle will take a 33T chainring as the minimum and that's not a significant improvement over your 34T. To go smaller you need a triple crank. There are modestly priced 10-speed Triple cranks such as the Shimano Tiagra FC-4603 which has a 30T smallest ring but can't go any smaller. Also, the out-of-production but still available 105 FC-5703 which has a 74 mm BCD granny and can have the stock 30T chainring replaced with as small as a 24T. Both of these can use your current 5800 bottom bracket cups but won't work with your double STI front shifter and probably not so well with your front derailleur.

Homebrew01

That might work. Remove the largest outer ring, and make a tiny double ?? 1 problem might be lowering the standard double front derailleur low enough, especially if it's a "braze-on" or something on the seat tube prevents it going low enough.

Andrew R Stewart 

I second the triple conversion suggestion. In my ideal touring bike I'd use bar end shifters, a 9 speed rear end, a triple crank and mountain ders. For the crank I prefer the narrower "Q" of road bike ones. Also I question the life spans of the very narrow chains as well as the likelihood of finding replacements once away from the western world.

But in the Op's situation just swapping out the crank and shifters is likely the cheapest choice. Maybe the ft der also? Andy

gsa103

That's unlikely to work. The chainring positions are in the wrong place, and chainring spacing is slightly different. You quickly wind up with a heap of different compatibility issues, and I'd be surprised if you could get it to work without resorting to friction shifting.

I'm speaking from experience here, since I tried doing the reverse conversion on my mountain bike (replace the outer ring with a bashguard). Shifter was switchable between 2x or 3x. Removed the outer chainring, set the shifter for 2x, and the shifting was utter garbage. I wound up leaving the shifter set for 3x and using the high-limit screw to block the outer position.

Phil_gretz

Ugh. What a mess. Turkey?

Okay. Sugino XD triple, with new bottom bracket cartridge. Go low: 46/36/26 or so.
Triple compatible front derailleur controlled by a left bar end friction shifter. Leave the 5800 left brifter as a brake lever. Test whether 5800 rear derailleur can handle the take-up range. Maybe...

HillRider

+1 on the barend shifter for the front shifting as that's the least expensive way to handle a triple conversion. The 5800 series doesn't have a triple STI option so it's either use the barend, which will shift nearly anything or a 5703 105 or 4703 Tiagra STI left shifter and I don't know if they would index well with the Suguino crank.

The 5800 GS rear derailleur will not handle the wrap capacity any triple gearing requires so you would give up the ability to use the smaller few cogs with the granny chainring if you made the chain long enough to allow big-big (which is essential for mechanical safety). In fact, your current gearing of 11/34 and 50/34, which is 39 total teeth, slightly exceeds Shimano's spec of 37 teeth of wrap capacity.