New GRX crank - do I need FD?

[merlinmurph]

OK, the last 15 years or so have been a steady progression towards lower and lower gearing. That's life, I guess. Luckily, the bike industry has become more realistic in their gearing options and, after thinking about this for awhile, I'm going to get a GRX crank with 46/30 rings. We're soon headed back up to Franconia NH for a month and those 15-20+% climbs would be more bearable with the 30-tooth ring.

I currently have a Ultegra 6800 compact 50/34 with the BBR60 BB and 6800 FD.

I'm pretty sure the new crank will work on the current BB, right?

Do I need a GRX FD? I thought the GRX crank had a higher Q factor and that the GRX FD may be needed. Has anybody gotten away with their road FD?

Thanks,
Murph

[Likes2ridefar]

The bb will be fine and I’ve read it’ll work with a non grx FD but no first hand experience.

I went through a similar exercise and ultimately decided i didn’t want to deal with changing the fd if necessary so I got a praxis Zayante Carbon crankset for $25 more than the grx I was considering. 48-32 rings.

[Gummee]

without looking, the GRX stuff sits 2.5mm further outboard than 'normal' cranks.

I'm pretty sure that Shimano sez 'normal' front derailleurs won't work, but 2.5mm isn't a big jump.

I'd say that if you want to go GRX, try the front derailleur you have now and adjust the limit screws out.

M

[marciero]

My GRX crank was plug and play with the 6700 bb and fd that were on the bike.

[merlinmurph]

Thanks, guys.

[fa63]

Mine works fine with a regular 7000 FD. The high limit screw is pretty much maxed out though.

[roydyates]

All of my old spare shimano FDs would get too close to the GRX crankarm, so I got the GRX FD which works nicely. Get the GRX derailleur. If for no other reason, it’s the first new geometry for Shimano mechanical FDs in like forever.

[Gummee]

All of my old spare shimano FDs would get too close to the GRX crankarm, so I got the GRX FD which works nicely. Get the GRX derailleur. If for no other reason, it’s the first new geometry for Shimano mechanical FDs in like forever.

If by 'forever' you mean when they changed from 10 to 'long arm' 11?

Or 'forever' you mean when they changed from 'long arm' 11 to the new 11 with the tension adjustment on the derailleur itself?

or 'forever' you mean the CX 75 stuff?

M

[leftsidedrive]

BOOM
https://forums.thepaceline.net/showthread.php?t=241232

[merlinmurph]

BOOM
https://forums.thepaceline.net/showthread.php?t=241232

Thanks! I did a search before posting and missed this one.

Thanks again everybody, and have a great ride