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Gearing up for the Rockies....

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Gearing up for the Rockies....

Old 07-29-22, 09:32 AM
  #26  
bamboobike4
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Originally Posted by Iride01 View Post
I don't remember if any said it, but your best bet for reducing the gearing is to get another crank with smaller rings. Otherwise you are going to get into mountain bike parts on a road bike and the compatibility issues which might crop up between them.
That was kind of the crux of my question, swapping in GRX 46/30 for Ultegra 50/34.

Originally Posted by Iride01 View Post
The GRX Shimano crank will probably fit without changing your BB. However it's chain line is 47 mm and the current crank on that Domane is probably about 43.5 mm. So even if the crank fit the BB shell width, the shifting will be crappy trying to get to the low ratio cog on the back. If it would even get there.
I'm going to go with the 2mm inward spacers on the GRX, swap that in, and if it works, fine. It has for others here on BF. Otherwise, not going to the expense of the GRX Di2 FD ($250) for this one ride, but may consider it for the next 4-5.

Originally Posted by Iride01 View Post
Still I bet you both will make it on your current setups. Like I did for my big climb last year, you are probably worrying too much. I did way more training and prep than I needed too. Though in the end, being prepared is what makes it easy.
This has been our experience elsewhere. Anxiety-driven preparation often enabling a fine day when it finally comes.
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Old 07-29-22, 09:34 AM
  #27  
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Originally Posted by Canker View Post
Absolute Black makes sub compact chainrings that will fit a 6800 crank. I'm running their 46/30 rings on my 5800 cranks and I didn't need a new FD. AB's rings are expensive so you'd have to decide if it makes more sense to go GRX or AB rings. If I were doing it now I'd go 48/31 GRX.
Thank you. One of my friends just happens to be one of their ambassadors. I'll check with him.

Last edited by bamboobike4; 07-29-22 at 10:01 AM.
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Old 07-29-22, 09:59 AM
  #28  
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Thanks for all the info....

I've gathered the great advice and devised a set of plans, if not for now, certainly for the future. Tech/Equipment is moving so fast.

Plan A:
GRX crankset 46.30 (already on her gravel bike)
Shares the same BB type.
2mm spacers inboard for each ring (8 total)
Try it and see if it shifts with the Ultegra Di2 FD.
Check chain slap and either remove link(s) to work a bit better, or buy a chain.
Will be a 46/30 front, 11-36 rear, 170mm cranks and she gives up her Stages power meter.
About $15 for the spacers, and another $50 for a chain if needed.

Plan B:
Absolute Black 46/30 rings
Absolute Black special bolts (come with rings)
Absolute Black bolt caps
Try it and see if it shifts with the Ultegra Di2 FD (it should.)
Check chain slap and either remove link(s) to work a bit better, or buy a chain.
Will be a 46/30 (oval) front, 11-36 rear, 170mm cranks and she retains her Stages power meter.
About $190 for the rings/caps, and another $50 for a chain if needed.

Plan C:
GRX crankset 46/30 (already on her gravel bike)
Shares the same BB type.
GRX Di2 FD
Try it and see if it shifts OK (it should). Chain line should be OK, not super.
Check chain slap and either remove link(s) to work a bit better, or buy a chain.
Will be a 46/30 GRX front, 11-36 rear, 170mm cranks and she loses her Stages power meter.
About $250 for the FD, and another $50 for a chain if needed.

This is all pretty much fun to think about, but basically, Iride01 and others are not wrong; she could be fine with the current 50/34 and 11-36.
We hope to climb each pass in the studio before we leave next week. Plenty of acclimation time, staying at 6500' for a few days, then 8500' until the event.

Thanks to everyone who shared their thoughts, opinions, and advice.
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Old 07-29-22, 11:46 AM
  #29  
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shimano says use the grx derailler with the crank, but of course they would https://bike.shimano.com/en-US/infor...ad-compon.html

here is compatibility chart for di2 https://bike.shimano.com/en-EU/e-tub...atibility.html

it seems if you want a slam dunk, minimum fiddle set up go with grx crank and front derailler
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Old 07-31-22, 12:31 PM
  #30  
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Originally Posted by bamboobike4 View Post
Join the club. A mechanic, I ain't.

I only know "little in front, big in back" is better for climbing.
Making it all work, fun.
I finished my climber last night: 50/34 front, 11-34 rear, DA9100 with a Roadlink DM.
Hits all the gears just fine, both big and small rings, but not real happy getting in/out of 11T.
1996 frame, maybe it's just mad about it.

I'll ride it tomorrow night on hill repeats and see what's up. We do 6 climbs, 11 miles, 1900'. Repeat if time permits.
The Di2 Dealer's Manual pdf (recommended--these pages are easy for a non-mechanic to follow) explains that the high limit screw needs to allow for an "overshift" to get into the smallest cog:

Shift the rear derailleur to the smallest
sprocket, and then tighten the top-side
stopper adjustment bolt until it touches
the stopper at the position where the
rear derailleur finally stopped. From this
position, turn the top adjustment bolt
counterclockwise one turn
so that an
over-stroke allowance can always be
maintained.

The manuals are here: https://si.shimano.com
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Old 07-31-22, 05:22 PM
  #31  
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Originally Posted by bamboobike4 View Post
Appreciate it, and noted. It's about the bike setup I'd like to do.
I know the rider. (see my earlier post).
Low wattage.
Normal rpm (rarely over 90, rarely under 75)
High endurance (has done 228 in one day, 107 centuries)
Lower speed (Averages 15-16, but has a 5:29 century and a 13:29:00 for 228 ina 6-man pace line, a year ago, but that was a special year,
Rides by HR and sticks to it.

But I'll get specific on the route(s):
-Triple Bypass, 106m/10,900' event support though we're hoping for an extra stop or two.
-Cherohala Challenge, about the same, event support
-Six Gap, roughly the same
-Dairyland Dare, shorter and steeper.
-----If successful at the first 4, probably Horrible Hilly Hundred.

Last year was an endurance year, and we trained for it.
Coming off a rough winter/early spring, we're planning Colorado, and then go from there.

I'm asking about the bike setup, specifically, for this ride and 3 others, using what works now on the rear and gaining some improvement on the front.

All the advice is great, though.
A 30-36 is a 22.5-inch gear and almost low enough for loaded touring. Find some hills close and let her try it.
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Old 08-01-22, 10:00 AM
  #32  
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Originally Posted by davidad View Post
A 30-36 is a 22.5-inch gear and almost low enough for loaded touring. Find some hills close and let her try it.
I appreciate the information. I know what the gears are, thanks, just wanted to know about the setup.
We did 8,100' Saturday over 104 miles, and she was OK, feels better about heading west.

Last edited by bamboobike4; 08-01-22 at 10:07 AM.
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Old 08-01-22, 10:05 AM
  #33  
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Originally Posted by rm -rf View Post
The Di2 Dealer's Manual pdf (recommended--these pages are easy for a non-mechanic to follow) explains that the high limit screw needs to allow for an "overshift" to get into the smallest cog:

Shift the rear derailleur to the smallest
sprocket, and then tighten the top-side
stopper adjustment bolt until it touches
the stopper at the position where the
rear derailleur finally stopped. From this
position, turn the top adjustment bolt
counterclockwise one turn
so that an
over-stroke allowance can always be
maintained.

The manuals are here: https://si.shimano.com
My bike is not Di2, hers is. I am sorry for any confusion.

My issue was an IRD 11-34 11-speed cassette (very light, not expensive at all) that does not play all that well with my DA 9000 setup.
On a Colnago Master Extra Light with 50/34 DA 9000, it would not shift well under moderate or higher load.
On a Litespeed Classic with 50/34 DA 9000/9100 mix, it would get cranky (pun intended) on the lower small cogs.
On the rack, fine, and on the same cogs, on the big front ring, fine, and I could move straight to the small ring, no issue.
Trying it under load on either, loud complaints from the back end.

My guess is a chain/cassette compatibility issue (SRAM 1071 and KMC X.1), but I swapped in my Shimano 11-34 cassette instead and it works fine on the Colnago. I'll figure out something with those two IRD cassettes, maybe use a different chain or step back, refresh, remove the chains and re-set the RD's. FD's work fine.

Last edited by bamboobike4; 08-01-22 at 10:11 AM.
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Old 08-01-22, 10:10 AM
  #34  
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Originally Posted by squirtdad View Post
Shimano says use the GRX derailleur with the crank, but of course they would https://bike.shimano.com/en-US/infor...ad-compon.html

here is compatibility chart for di2 https://bike.shimano.com/en-EU/e-tub...atibility.html

it seems if you want a slam dunk, minimum fiddle set up go with GRX crank and front derailleur
Thanks. I may end up doing just that. Just to avoid a lot of trial and error.
We leave in 3 days, and ran a pretty decent training climb Saturday, 8,100' over 104 miles, mostly leg-punchers.
She did fine, and our approach is to take it easy, enjoy an all-day ride.

So, now I'm in disassemble, clean, lube, adjust mode. Everything needs to be sparkly, right?
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