996

Hi Guys,

I have a Black Mountain Cycles Road frame (rim brakes) currently set up with Shimano 105 (50/34) x 11-34. Looking to upgrade the rear cassette to an 11-40 cassette to tackle the steeper fire roads in my area. Recently read this:

https://road.cc/content/feature/how-...entures-246424

They achieved this type of gearing with the R7000 RD without a road link. I obviously won't be running big ring to big cog gearing, but wanted to check in and see if anyone has achieved this.

Thanks!

mstateglfr 

A guy I ride with, or used to I guess, has a 105 5800 drivetrain with 50/34 and 11/40 using a wolftooth roadlink. If the 580p gs rd can handle it, I would guess the r700 rd can.

For what its worth, 30/34 is basically the same ratio as 34/40. Another option is to buy a 46/30 crank.

Elvo

It's possible but depends on your frame geometry. You won't be able to use small/big or big/small due to chain wrap capacity issues.

996

Got it. By small/big do you mean small chainring up front and largest cog in the rear? or Small chainring up front and biggest gear (smallest cog) in the rear?

Thanks!

Elvo

Whoops I meant small/small and big/big

Barrettscv 

I’m using the 48/31 GRX crankset and I highly recommend it for disc brake bikes. This is your best option.

On a different bike, I have an 11-36 eleven speed cassette with the earlier 105 rear derailleur (no Wolflink used)

I can use all 22 gear combinations on both drivetrains without any mechanical issues, plenty of safety margin and no risk to the drivetrain. I do avoid the the big-big and small-small combination just as a best practice.

shoota 

Yep, I'm gonna suggest adjusting your crankset to achieve what you want as well. While the roadlink might work I think you'll have a better experience staying within spec, or very close to it. For example, my RX Ultegra and R7000 105 RDs can both do an 11-42 in 1X mode but it's not always a great shifting experience. I would expect that putting them under the same pressure with a 2X 11-40 setup would cause the same issues. Get a lower geared crankset and reap the benefits of reduced weight and better shifting.

996

shoota Barrettscv

Would it be possible to find a 46/30 chainring set for my R7000 105 cranks?

Thanks!

Barrettscv 

I had the Absolute Black 46 & 30 chainring set on an Ultegra crankset and these can be installed on a 7000 crank. They are an option but these don’t shift as well as OEM rings. I’m also not convinced that the improvements in performance are genuine. I took the oval chainrings off my road bike and put them on my trainer.

shoota 

Really? How does Absolute accomplish this? Is the small ring directly mounted to the big ring?

Barrettscv 

Both rings mount on the original tapped holes. Since the 4 arms are spaced as pairs, the oval rings are wider where they attach to the crank arms and the ring shape is narrower between the pairs of arms. Notice the gap at the derailleur cage is larger at 90 degrees to the bolt location






The Absolute Black chainrings do alter the chainline. The chainline is inboard of the original chainline. I wouldn’t want to use the rings on a disc brake bike. The chainline on the smaller cogs would be unacceptable with anything but a 130mm road hub.

jaxgtr

Wouldn't the GRX rings work on the 105 cranks? They are both 110/80 bcd bolt pattern

Barrettscv 

Not correct, the 105 and Ultegra (pictured) eleven speed cranks are 110 (only).

wheelsmcgee

Look for “bikingreen” 46/30 chainring set on eBay. I bought it for my r7000 cranks to try out on my warbird. It’s about $80 and is of decent quality. Unfortunately, it didn’t work on my frame because moving to a smaller little ring got the chain too close to the chainstay. I might have been able to mitigate the problem with some spacers, but in the end decided to just get a larger cassette.

FWIW, I had the full r7000 group on my warbird, and 11-36 works just fine without a derailer hanger extender.

996

I managed to make this work. Shifts fine. 50/34 x 11-40 on an R7000 RD without a road link.

shoota 

Even crosschaining, or no?

Elvo

Not enough chain wrap for 34x11 if you sized for 50x40, 50x40 might roughly function but your derailer will look/sound like the cage is about to snap off

mstateglfr 

obligatory pic time, especially since its of a frame that was so neat and no longer in production.

996

Even when I crosschain - 50 big ring and 40 small ring. Although not smooth. I obviously don't run it like this ever.

996

Will upload soon!

996

mstateglfr shoota - I am also running Panaracer Gravel King SS tires in size 32C. Taken them up all the fire roads in Los Angeles with no problem or loss of traction. The descents could get dicey if you are trying to bomb them... and I thought for sure I may have blown a tube (yes I run tubes) on a massive crater I struck on a fire road descent... the tires are super strong. No flats yet.

Gearing is great. I get a ton of range.

shoota 

Nice rig dude. What about 34x11?

mstateglfr 

Awesome looking build. Ive seen the black carbon fork on a couple other builds and think it looks really great(the original steel fork is nice looking too). Maybe toss the QR skewers on the non-drive side?...sorry, I couldnt help myself.
Anyways, its a really neat build and super versatile.
I came very close to buying this frame a couple years ago and slapping a Whiskey fork on it, but opted to take a winter season framebuilding class instead. I ended up with a road bike that is mostly orange and shares a lot of the same geometry as the Black Mountain frame I was considering!
Its a shame Mike killed off this road frame, but demand demands it so it happens.

996

mstateglfr Ooops - idk why I did that lol. Most def will switch them up. Appreciate it!

shoota Will try and get you a pic of that soon.