ph0rk

I have a BB86.5 bike (Domane alr 4 disc), with a tiagra 4700 34/50 compact crankset. I moved to the mountains, and I really don't like my low gearing options, even with a 32t cog in the back. Plenty of category 2 and 3 climbs to be had here on the regular routes into and out of town, and some harder stuff, too. Lots of short bursts at > 15%, and I'm not ashamed to say I don't have the legs for it right now.

Wolf tooth claims the tanpan won't work with 4700 tiagra, so smaller chainrings seem the cheapest route, only the 0x901D is ~$400+, and dealers are rare as hen's teeth. FSA supposedly has subcompacts in the $150-250 range on the way, but I've heard nothing. Praxis works is sort of annoying in how proprietary their stuff is, and I'd prefer 30/46 to 32/48.

Are there any other options, or am I going to have to go 1x to get the climbing gears I'd like (ideally, 24 gear inches or so, which 30x34 would do, requiring an 11-34 cassette along with the new crankset, but little else.) Switching over to a triple would probably cost about as much as going 1x, as the bike has full hydro braking - if they even make a triple tiagra lever in hydro. (I'd probably go mechanical/hydro hybrid if I swapped levers, FWIW).

I feel like I'm sort of stuck spending money either way, and that's fine. Any suggestions would be appreciated.

gsa103

Tanpan doesn't work because Tiagra 4700 uses the 11-speed cable pull ratios.

A Wolftooth RoadLink would shift your current derailluer down enough to get you the clearance for a 34t or 36t cassette.
https://www.wolftoothcomponents.com/...ducts/roadlink
That's probably the cheapest option.

fietsbob

Get a triple crank.. road triples add a 30t , so the shifting is not slowed down too much..



I plan ahead, so I can run even smaller 3rd rings ... shift down early, don't attempt to upshift until I crest the pass, and head down hill..

<C> 135/74 .. 50,40, 24.. (took off the 30t), 'race triple'







....

Cyclist0108

Having been through this (and having purchased a 46/30T crank that makes the Sugino 0x901D subcompact seem thrifty), I think the most cost-effective way to do this is with a larger cassette. I found my Shimano Ultegra Di2 derailleur, rated for max 32T, handles a 36T SRAM cassette with no significant issue, after B-screw adjustment). To go larger, the wolftooth with current derailleur, or a new mountain bike rear derailleur, are the cheapest options, as already mentioned. Next in line, IRD makes a 46/30T square taper-compatible crank for about $200.

tyrion

Can't a tiagra 4700 shifter drive a mountain RD? An SLX RD + 36t cassette would be less than $100 and get you to 25-26 gear inches.

Racing Dan

The 4700 GS RD is said to do 36t, two more than its rated for. That gives you ~25.5" gear inches.

TimothyH

That's right, a 34 front ring and cassette with a 36 tooth rear sprocket will get 24.5 to 25.5 gear inches depending on tire size and which online calculator is used.

I'm running an Ultegra GS derailleur, Ultegra 50/34 compact road cranks and a SRAM PG-1170 11/36 cassette. The B screw is turned in quite a bit but my bike shifts flawlessly and I crosschain the crud out of it. It would need a Wolf Tooth if the cassette were any bigger and I would not have hesitated to use one were it needed.

Note that I said it works on my bike. Whether it works on any other bike depends on the bike itself but many people run road bikes with GS derailleurs and 36 tooth sprockets.

I don't know about Tiagra but if the OP can swap the cassette and maybe a chain, that would be the cheapest way to go.


-Tim-

TimothyH

Also want to say that I think the Sugino 0x91D Compact+ is gorgeous.




Comes in silver too.


-Tim-

gsa103

No. The shifter uses the same cable pull ratio as 11-speed Shimano, just set for 10-speed cog spacing.

Art's Cyclery Blog » Science Behind the Magic | Drivetrain Compatibility

The 4700 derailleur has a 1.4 ratio, and a cable pull of 2.8mm. As you can see that makes it really strange.
If you're at all interested in cross-compatibility 4700 is by far the worst group.

ph0rk

Current plan is to try a 11-36 cassette and see if that helps grunting up the climbs. If not, then the sugino 0x601d (matte silver, but at least I can order it relatively easily from soma) in a 30/46 or an FSA gossamer adventure in 32/48 (at half the price) will be the ticket.

OneIsAllYouNeed

Another fun alternative:
SRAM Rival 22 or Force 22 crankset (they should fit the 86.5 bb).
Replace the spider with a 4-bolt 94 bcd one. Use whatever chainrings you want from there.
Road bikes with small big rings sometimes have clearance issues related to the front derailleur hitting the chainstay. An MTB front derailleur may be necessary.

edthesped

I purchased mine from Hubjub for much less than Soma...

Sugino OX601D crankset

Racing Dan

Good idea.

edthesped

I overlooked the BB86.5 part, will any of the Sugino compact +'s work with a wider than 68mm BB Shell?

TimothyH

Lots of options listed here...

https://www.bikeforums.net/fifty-plus...road-bike.html

ph0rk

Yeah, I sifted through it pretty extensively. The FSA stuff is still largely unobtanium, and I'd rather not pay MSRP for a Gossamer crankset, anyway. (The Vero I had on my crossrip soured me on FSA). That said, the SL-K sounds interesting, but I don't know how I feel about carbon crank arms. It also seems to be not offered or very hard to find in 30/46.

Square taper cranks won't work on this bike, AFAIK.

White Industries manages to cost more (!) than the Sugino.

The willow tripleizer, on the other hand, looks pretty neat. Not sure the Tiagra FD will play nice, though (which would be a problem regardless of which chainrings/crank I went with). Would require a 130bcd crank, of course.

Many of these options start to mission creep to replacing the entire tiagra group. Once I'm fully open to that, sky's the limit, I guess. I am as likely to go 1x as I am to give Gevenalle 2x (with a mtb rear derailleur) a try. The fact that I am growing to detest STI shifting isn't helping my wallet, either.

TimothyH

@ph0rk, what did you decide?

How did this play out?


-Tim-

70sSanO

I know this doesn't exactly apply because I'm still using downtube shifters, but my triple setup is 30/38/46 on an Ultegra 6503. The nice thing about this setup is being able to run a 30/46 or even a 26 or 28/46 and still have an all-purpose 38t. My wife is running 30/39/46 with brifters. My prior double was 38/46 because 38t was the smallest chainring that would fit on a 130mm, but I do like having that 30t. While I would never profess turning back the clock to the downtube shifting days, it is nice to go from 30 to 46 in a single shift as you crest and then go downhill.

John

Retro Grouch 

What are you willing to give up to get an easier hill climb gear? You're going to have to give up something because the laws of physics can't be violated.

A crankset with smaller chainrings will sacrifice your high speed gear. One real big chainring and one real little chainring is going to shift funny.
A cassette with bigger cogs will have bigger spaces between gears and may also have shifting issues.
A Triple crankset - well, it's a triple. To do it right you'll have to replace a lot of parts but that would still be my choice.

Cyclist0108

A 50T chainring with 12T cassette gear = 46T chainring with 11T cassette gear

So unless you spend a lot of time in 50T/11T, you aren't giving up much.

My Athena-11 triple has 52/42/30T, so I gave up nothing on that one -- shifts fine. (I did give up my friction shifters on the down-tube, which I actually miss. The only thing I like better is Di2).

fietsbob

It's like a triple that will not take an outer chainring.. because of the crank spider design.


tripleizer middle chainrings have like 10 bolt holes, , 5 mount it to the crank spider, and 5 mount it's smaller chain ring to it.

Off the top of my head .. the latest Brompton Spider crank has a 130 bolt circle chainring only on the inside face.. Square taper JIS, I think.

TA of France makes a 130/74 tripleizer chainring in 7074-T6 aluminum .


not cheap , but it is an alternative..




....

Marcus_Ti

Problem with triples...today's groups there's basically no support for triples in shifters or derailleurs on the road side....other than Campag Athena. Easily sourced options for road-ish triple stop with 10 speed.

hermanchauw

I simply went all the way to 22-32-42 mtb cranks. Shifted with mtb shifters. Basically full mtb drivetrain. Problem solved.

ph0rk

Still going with the 32/48 SRAM double and a 11-36 cassette on the commuter and a 34-50 with 11-36 (works with new Tiagra) on the road bike. I was on the verge of going 1x11 out of frustration, but decided to wait as work got busy.

And so: 3-4 months of steady mountain riding worked wonders. I’ve only been doing short hill repeats lately (in part due to the weather), so I don’t know how a long climb would go. I’m loosely planning on a 200k with 14k of climbing this spring, so we will see.

I’ll say this: I still don’t need 50x11 ever. Gravity already gets me faster than I like for the downhill twists, and 50x15 or x13 is usually more than I need.


It looks like 32x48 is a bit more available than it was, I’ll dig back into it this summer.

cpach

The FSA cranks are available now. https://shop.fullspeedahead.com/en/e...-crankset-4254 . They make a BB for 86.5mm shells. Very similar deal with Praxis.