jppe

Here we go up Brasstown!!! Crazy easy gear but I’m all in for it. Nice looking Niner.

DougG

I've been using a FSA 46/30 with an 11-32 cassette for a couple of years, but this summer I encountered a couple of hills that had me struggling. So right now there's an 11-34 cassette down on my workbench that I'll install when I bring the bike in for the winter. One thing about the 46/30 is that I find that I'm pretty well spun out at between 25-30mph. On the other hand, I'm only going to see that speed going downhill when, at 73, I have no business pedaling to try to go faster!

marcoguzm

DougG

You'll like the 11-34 cassette, and you can even find a Sun Race 11-36, though it's heavier. I've tried in some hills the 30/30 combo, but I can't sustain the pace for long. The 30/34 is good for tough climbs. And for those extremely hard climbs, I guess it would be better with a triple crankset, e.g. 42/32/22. I've got that combination in a Norco and a Breezer, Ritchey Logic steel, from the 90's.

DougG

I thought about that, but the 11-34 is right at the limit of my rear derailleur capacity, although I could get away with it as long as I don't use gear combos that I shouldn't be using anyway, such as big-big. But actually I'm only going to encounter hills like that once or twice a year since 99.9% of my riding is close enough to flat that I have rarely even used my 30/32 gear combination.

Of course, I could always go wild and enter something like Michigan Mountain Mayhem, which has 10,000 feet of climbing on one of its routes, all of the short-but-very-steep variety (no actual "mountains" in Michigan!). It was a couple of these roads that really killed me this summer on a hot summer day (and I'm not getting younger at 73 and counting!).

DougG

That's exactly my bike:


At the time I bought it when it was first released, the VR5 came with a 48/32 crank, but the next year I replaced it with the FSA SL-K 46/30 that you mentioned. I really like this bike! It's great on all kinds of surfaces, nice and light carbon frame, and looks really good. I now have 700x32 Conti 4-seasons on it, which I found to be an improvement over the original 700x28s when riding on the gravel.

You're definitely making a good choice!

Barrettscv 

I’ll be installing my FC-RX810 48/31 on my Canyon Endurace this week. The bike now has a Ultegra R8000 50/34 with an 11-32 cassette. I rarely pedal at speeds higher than 35mph and I like the idea of staying on the big ring except on longer climbs of 5% or more. There are numerous 10-15% climbs in my area, so the 31/32 low gear will allow me to stay seated and spin my way to the top.

OldsCOOL

Nice looking crankset!

Barrettscv 

The GRX cranksets are an excellent match with disc brake bikes like the Endurace. The chain line is about 2.5 mm further offset than the r8000 Ultegra crankset. This works with the 142mm thru-axle but would probably not be as functional with a rim brake bike. I also installed the matching GRX front derailleur. The results are seen below. I’ll probably upgrade the rear derailleur the next time I install a new chain. However, changing the rear derailleur is not required unless other changes, like a 11-36 cassette are also planned.


Looking correct, this is a functional and aesthetic improvement over the Ultegra

Crankarm a clears the chain easily while on the big chainring and small cog

Chain line on the small-small combination. No contact or interference

Derailleur arm while on the small-small combination

Derailleur arm on the big-big combination

SCTinkering

Well that example of GRX on an existing Ultegra bike kind of seals the deal for me. Looks like my 2003 Airborne is already topped out and I'll be picking up a new T-Lab Ti that's built for discs and a 17 year newer drive-train. I was kind of hoping I could swap out to GRX crank and derailleur on the front (with a hydraulic front brake). There's nothing wrong with my Ti frame other than it is showing the limits of the available designs in 2003.

Of course that's me complaining that my road bike ONLY lasted 17 years...

Cyclist0108

In my case, it is an Ultegra Di2 derailleur with a band-clamp on a steel frame (uniform seat tube allows me to re-position the derailleur height). So YMMV, but it is at least worth a try.

mikemjd

Hi all,

It's been very interesting reading this thread. I'm wanting to covert my current Shimano 105 5800 50/34 setup to some kind of 46/30 setup (got a sportive coming up with cobbled climbs).

@Barrettscv, @wgscott, do you think there's no way the GRX chainset and front derailleur combo would work with a rim brake frame?

I think my only other option is the Absolute Black 46/30 chainrings, fitting them onto my current crank, but they're pricey!

Thanks

Barrettscv 

I've installed a 48/31 Shimano GRX chainset on a disc brake bike, my Canyon Endurace. I've also installed a 46/30 Absolute Black oval chainring set in my Ridley Helium SLX. I used a Shimano Ultegra 6800 crankset with the Absolute Black rings on a Ridley rim brake bike with SRAM Red eTap 2x11 drivetrain.

The Absolute Black chainring set worked well enough but had a few issues. The chainrings are set inward toward the derailleur providing a chainline that is different than OEM but not really a problem. I had to use all of the adjustment on the inner set screw to position the derailleur cage correctly. I found that the shifting of the chainrings was a little more fussy than the OEM chainrings and was audibly louder than OEM. I also dropped the chain once a day.





I transferred the chainrings and crankset to bike with an Ultegra 6800 drivetrains and had far fewer problems. I don't think the Absolute Black chainrings were a good match with the electric shifting but was very good with Shimano mechanical shifting.

You could try to install the GRX crankset on a rim brake bike, it will install without modifications needed. You will need to use the matching GTX front derailleur. The chainline on the big-big combination will be extreme and should probably be avoided.

mikemjd

Thanks for getting back to me Barrettscv, sounds like you have some nice bikes! I'm going to add an electronic bike as soon as the right one comes up.

Going from what you've said, it sounds like the Absolute Black rings on my mechanical groupset would be the best idea, I do feel like I want to try the GRX setup up though.

It really is a surprise to me why more people don't ride these gears, especially in locations with so many great climbs.

jppe

I was finally able to do several rides using my new GRX 46/30 crank and compatible FD. I wasn’t happy with how I’d setup the FD. The trim was working so there was a lot of chain rub on the big ring and smaller cogs. Plus to go from the 46 to the 30 took pushing the FD lever twice. That was really inconvenient when going from a quick downhill to a steep uphill.

The FD height was okay but I adjusted the lower limit screw so the inside plate on the FD moved closer to the frame. That allowed me to better align the two lines on the FD. Everything is shifting as it should now. For whatever reason I never seem to be able to get a FD adjusted the first time around.

hikerbikerguy

I am installing a grx crankset with a 68mm bottom bracket. Do I need any spindle spacers? Looking online it seems that I should always have then for any hollowtech ii, but the grx installation guide doesn't mention any.

Cyclist0108

I did not need any with mine.

Cyclist0108

Probably too late, but I don't see why it wouldn't work with a rim brake frame. Chain line?

aplcr0331

I have a 2019 rim brake Cannondale SuperSix (the last of the traditional ones not the new faster aero one with dropped seatstays) with Shimano R7000 FD and RD (it's the long cage one the GS model) and 50/34 Spiderings. The actual crank is an FSA with a BB30A (PF30A) BB. I have Cannondale crank arms (175) on it.

I'm wanting to go down to a 46/30 and read through this thread and low and behold Cannondale actually makes a 46/30 Spidering! If I get the 46/30 I should be able to just drop those new rings on there correct? I'll have to adjust the FD and RD of course, are there any other things I should look out for? It's a 16t jump between the 50/34 and the 46/30 so does that mean I won't need to adjust the chain? I have two wheelsets one with an 11/32 cassette and the other with an 11/34. Both should work without adjustment, correct...meaning I can swap them out without changing anything on the derailleur?

Appreciate any assistance. I got nervous looking at crank arms and thinking about new FD/RD and then throwing in the confusion over the stupid CDale BB stuff (even after all these years I still don't follow it, lol) I'm hoping this is a simpler solution with the Spidering installation.

Bean Counter

I did this to 2 road bikes with rim brakes this fall and installed 11-42 casettes on rear. Was told by my doctor to watch my heart rate while exercising, so made the switch to help on hill climbs here in Colorado. Wish I had done this a long time ago. One negative for some might be spinning out when descending. When that happens I just coast & enjoy the ride. At 68, I'm not looking to set speed records anyway.

Fr0hickey

Going from 50/34,11-34 to 46/30,11-32 will require some changes.
With the 4tooth decrease in chain ring and 2 tooth decrease in cassette, the chain length will need to decrease as well.
Front mech will need to be dropped lower to stay within 1-3mm from the largest chain ring.
Rear mech can handle a 2tooth difference between 11-34 and 11-32.

aplcr0331

OK, thanks for the tips. I'll make sure to watch the chain length. I'm thinking I might take the current chain on my bike and move it to the trainer. That way I'm running a new chain with the new chainrings.

Appreciate it.

Calsun

My 20 year old Trek has the original 53/39 chainrings and having the 39t took a bit of getting used to as my other bikes had 52/46 chainrings. If I need a lower gear than I prefer to put an extra large rear sprocket on the cassette. Instead of the 12-25 with normal riding I would replace the 25t with a 28t and if I wanted to go lower I would put on a 34t sprocket and replace the rear detrailluer with a greater range one.

What I love about the gear shift incorporated into the brake levers is that I would not hesitate to switch gears and so did this far more often. Definitely helps in hilly terrain.

friday1970

Old thread here. But just ordered a Senicx Chinese 46x30t 165mm, BSA BB included.
This will go onto my 04 Fuji Ace, which has served as my randonneuring bike on mostly paved route. (the steel fork makes it comfortable).
The issue I had with my current triple is if I changed down to my 30t while changing my rear gears, occasionally, the chain would get caught in the space between the BB and the crank, where you have some square taper spindle showing. This usually required about 15 minutes to fix. And if you are on a 300K brevet or so, this time could add up.
Also, the bottom bracket bearings are shot too.
So, better gearing, lighter crankset/bb setup, and new bearings. I'd say that's a win!