Thinking of going 1x

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JMeinholdt
Posts: 764
Joined: Wed Feb 26, 2020 10:31 pm
Location: Topeka, KS

by JMeinholdt

Looking for a little input on my 1x conversion thoughts.

Current setup: 3T Exploro, Shimano 105 R7020 STI's, 2x 48/32 Praxis Zayante crankset, 11-34 cassette with an Ultegra RX RD. I went with 2x because I'll be doing some higher speed gravel racing and didn't want to be stuck with a really low top end with say a 42/11 combo.

For some reason, I don't know if it's my Praxis chainrings, the 105 R7000 FD, or the frameset itself, I've never been able to get really good front shifting. It's acceptable, but I typically have to shift down to the little cogs in the rear before I shift from little to big to prevent a chaindrop. I've also had a rock stuck in the FD once which made the cable slip and then I was essentially unable to shift the front at all for the rest of the ride.

Ideally I'd have liked to just move to SRAM AXS 1x but availability of parts and wanting to do this on a budget have me considering alternatives.

My questions are this: Would an Ultegra RX800 RD be capable of accommodating a 10-42 (XDR driver for my wheels is easy to source) 11 speed cassette with a roadlink? I know the RX can handle a 40T with just a b-screw adjustment, but would it be able to handle both the 10T and 42T with acceptable performance? It does have a clutch mechanism so I know that will help with tension.

If that solution will work, then my question moves to chainring sizing. I know I wouldn't go smaller than 42T even with a 10T cassette as a 1:1 is just fine since I'm not doing loaded bikebacking or anything. Would a 44T be better for racing purposes (probably 18+mph average on gravel)? If it matters, I typically race at a ~90rpm cadence.

Thanks for your thoughts.
Wilier Cento10AIR - SRAM Force AXS - Road/race
3T Exploro - SRAM Rival AXS XPLR - Gravel
Wilier Sestiere - Shimano Tiagra - Commuter

YouTube link: https://www.youtube.com/@JMCyclingVideos

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gorkypl
Posts: 529
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

I would think the FD adjustment is to be blamed for bad shifting. 48/32 is more difficult for road FD, but I have very good results even with 46/30 - precise FD setting is they key here though.
Regarding rear - I'm not sure to what extent you can accept much worsened shifting quality. In my experience RX800 with 11-36 is on the edge of being acceptable. I think 10-42 could somehow be made to work with roadlink, but I would expect high gears to be shifting really bad (big distance from pulley wheels to the cogs).
So for 1x I would rather go with RX-812, or stayed with 11-36 cassette.

As for chainring - 44/10 is faster than 48/11 - both seem to be overkill for gravel in my experience. 40/10 is the equivalent of 48/12, so if you currently don't use the smallest cog too often, you'd be much better with 40T front.

Fuji Cross 1.5 - Shimano 105 5800 | Cinelli Superstar Disc - Record 12s | Custom steel Karamba - Ekar 13s

JMeinholdt
Posts: 764
Joined: Wed Feb 26, 2020 10:31 pm
Location: Topeka, KS

by JMeinholdt

gorkypl wrote:
Mon Jun 21, 2021 5:33 pm
I would think the FD adjustment is to be blamed for bad shifting. 48/32 is more difficult for road FD, but I have very good results even with 46/30 - precise FD setting is they key here though.
I've thought this as well, however, I've also spent many hours fiddling with the adjustment every which way. The only way I can get an acceptable front shift is to adjust it so far outboard that I get rub on the inner FD cage when I'm in my lowest two gears. Like I said, I've adjusted it about as good as I can possibly get it and I still have to completely ease off, ensure my rear is down in the little cogs, and gently shift it otherwise I fear chain drop. And that's unacceptable in a race situation IMO.
gorkypl wrote:
Mon Jun 21, 2021 5:33 pm
Regarding rear - I'm not sure to what extent you can accept much worsened shifting quality. In my experience RX800 with 11-36 is on the edge of being acceptable. I think 10-42 could somehow be made to work with roadlink, but I would expect high gears to be shifting really bad (big distance from pulley wheels to the cogs).
So for 1x I would rather go with RX-812, or stayed with 11-36 cassette.
I may end up looking for the GRX 1x RD. It's just extra money I didn't want to spend. Unless someone else chimes in and mentions how great their Ultegra RX has been running 1x...
gorkypl wrote:
Mon Jun 21, 2021 5:33 pm
As for chainring - 44/10 is faster than 48/11 - both seem to be overkill for gravel in my experience. 40/10 is the equivalent of 48/12, so if you currently don't use the smallest cog too often, you'd be much better with 40T front.
Believe it or not, I spend quite a bit of time in the 48 x 11, 13, and 15. I've also spun out my 48/11 on a few of our steeper descents. But, I think 42T would probably be enough after considering your input. Doing some math, with a 42T ring I'd spend the bulk of my time in the 42 x 12, 14, and 16 as that covers from ~17-25mph at my preferred cadence with a 40c tire.
Wilier Cento10AIR - SRAM Force AXS - Road/race
3T Exploro - SRAM Rival AXS XPLR - Gravel
Wilier Sestiere - Shimano Tiagra - Commuter

YouTube link: https://www.youtube.com/@JMCyclingVideos

gorkypl
Posts: 529
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

JMeinholdt wrote:
Mon Jun 21, 2021 5:53 pm
I've thought this as well, however, I've also spent many hours fiddling with the adjustment every which way. The only way I can get an acceptable front shift is to adjust it so far outboard that I get rub on the inner FD cage when I'm in my lowest two gears.
This is exactly how it should be. When on big ring the chain should rub inner FD cage on two lowest gears - and this is the moment when you want to use the front half-gear (ie the first trim position).
JMeinholdt wrote:
Mon Jun 21, 2021 5:53 pm
I may end up looking for the GRX 1x RD. It's just extra money I didn't want to spend. Unless someone else chimes in and mentions how great their Ultegra RX has been running 1x...
It is fine for 1x, just with no more than 11-36....
JMeinholdt wrote:
Mon Jun 21, 2021 5:53 pm
Believe it or not, I spend quite a bit of time in the 48 x 11, 13, and 15. I've also spun out my 48/11 on a few of our steeper descents. But, I think 42T would probably be enough after considering your input. Doing some math, with a 42T ring I'd spend the bulk of my time in the 42 x 12, 14, and 16 as that covers from ~17-25mph at my preferred cadence with a 40c tire.
Spinning 48x11 at 120rpm with 40mm tires gives 70km/h - these must be some serious descents there that make you want to go faster :)

You know your terrain and abilities better, no doubts - but from experience I know that most people (including me) tend to overgear.
This is even more true for off-road, where I have much often prayed for easier gear rather than adding several km/h on a steep downhill. 4:1 is probably the maximum that I would use for gravel, YMMV of course.

Fuji Cross 1.5 - Shimano 105 5800 | Cinelli Superstar Disc - Record 12s | Custom steel Karamba - Ekar 13s

JMeinholdt
Posts: 764
Joined: Wed Feb 26, 2020 10:31 pm
Location: Topeka, KS

by JMeinholdt

gorkypl wrote:
Mon Jun 21, 2021 6:15 pm
Spinning 48x11 at 120rpm with 40mm tires gives 70km/h - these must be some serious descents there that make you want to go faster :)

You know your terrain and abilities better, no doubts - but from experience I know that most people (including me) tend to overgear.
This is even more true for off-road, where I have much often prayed for easier gear rather than adding several km/h on a steep downhill. 4:1 is probably the maximum that I would use for gravel, YMMV of course.
We don't have what I would call "serious" descents. But we have a lot of short steep inclines and declines where you can pick up speed really fast. I've never felt as though I've needed lower than my current 32/34 combo and in most climbing situations I'm actually in my 32/30 as the sub 1:1 tends to leave me behind the bunch.

I also want to consider that spending time in a 10T cog or even 12T isn't going to be as efficient for either chainline or chain wrap friction.

Ugh. Analysis paralysis. Always gets me.
Wilier Cento10AIR - SRAM Force AXS - Road/race
3T Exploro - SRAM Rival AXS XPLR - Gravel
Wilier Sestiere - Shimano Tiagra - Commuter

YouTube link: https://www.youtube.com/@JMCyclingVideos

gwerziou
Posts: 347
Joined: Wed Feb 20, 2019 7:25 pm
Location: Ballard, WA

by gwerziou

You could run an Ekar drivetrain and do a 42 front chainring and the 9-42 cassette. Huge range, 13 gears, works like a charm! You did mention the dreaded word 'budget' though...
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JMeinholdt
Posts: 764
Joined: Wed Feb 26, 2020 10:31 pm
Location: Topeka, KS

by JMeinholdt

gwerziou wrote:
Mon Jun 21, 2021 7:07 pm
You could run an Ekar drivetrain and do a 42 front chainring and the 9-42 cassette. Huge range, 13 gears, works like a charm! You did mention the dreaded word 'budget' though...
Believe me, I'd love that option. It is big $$ though... I'm fairly certain I could go AXS for cheaper...
Wilier Cento10AIR - SRAM Force AXS - Road/race
3T Exploro - SRAM Rival AXS XPLR - Gravel
Wilier Sestiere - Shimano Tiagra - Commuter

YouTube link: https://www.youtube.com/@JMCyclingVideos

gorkypl
Posts: 529
Joined: Fri Sep 21, 2018 9:31 am
Location: Poland

by gorkypl

JMeinholdt wrote:
Mon Jun 21, 2021 6:45 pm
I also want to consider that spending time in a 10T cog or even 12T isn't going to be as efficient for either chainline or chain wrap friction.
Nah, I think you can safely ignore it. Unless you would cruise using these cogs for long time, the losses due to friction are negligible.

Overall, i think you'd be fine with Grx rd, 10-42 cassette and either 40 or 42 chainring. Don't think you can make it with your current rd, though.
You can also try another attempt to fd adjustment. It definitely should work reliably, and you'll have more granular gears - 11s has quite big gaps for road 1x. 13x, yes, that's another story.

Fuji Cross 1.5 - Shimano 105 5800 | Cinelli Superstar Disc - Record 12s | Custom steel Karamba - Ekar 13s


JMeinholdt
Posts: 764
Joined: Wed Feb 26, 2020 10:31 pm
Location: Topeka, KS

by JMeinholdt

Decided to take things apart and try out a 42T chainring and 11-42T cassette keeping my Ultegra RX800 RD. Just threw the 11-42 on as I had it on another bike to try out.

https://youtu.be/gP9jxD-Qf7M

Turns out, the 11-42T is just a bit much for the RD. I do think 11-40T will be just about perfect so I've got one on order. Damn delays means it'll be the end of the month for my LBS can get it.
Wilier Cento10AIR - SRAM Force AXS - Road/race
3T Exploro - SRAM Rival AXS XPLR - Gravel
Wilier Sestiere - Shimano Tiagra - Commuter

YouTube link: https://www.youtube.com/@JMCyclingVideos

FactoryMatt
Posts: 1014
Joined: Tue Apr 14, 2015 4:35 am

by FactoryMatt

yes it is. 40 is the max with that derailleur. maybe a goatlink or road link would get it but not sure.

i have a few 11-40 XTR cassettes, if you need something right away, PM me and i'll consider selling for market.

JMeinholdt
Posts: 764
Joined: Wed Feb 26, 2020 10:31 pm
Location: Topeka, KS

by JMeinholdt

JMeinholdt wrote:
Fri Aug 13, 2021 10:19 pm
Decided to take things apart and try out a 42T chainring and 11-42T cassette keeping my Ultegra RX800 RD. Just threw the 11-42 on as I had it on another bike to try out.

https://youtu.be/gP9jxD-Qf7M

Turns out, the 11-42T is just a bit much for the RD. I do think 11-40T will be just about perfect so I've got one on order. Damn delays means it'll be the end of the month for my LBS can get it.
Ended up getting an 11-40T cassette installed and it works like a charm with my Ultegra RX RD. I will say though, it's definitely at it's max.

Done several rides now and I've had no issues at all with shifting or chain drops, but I do leave the clutch engaged 100% of the time on gravel.
Wilier Cento10AIR - SRAM Force AXS - Road/race
3T Exploro - SRAM Rival AXS XPLR - Gravel
Wilier Sestiere - Shimano Tiagra - Commuter

YouTube link: https://www.youtube.com/@JMCyclingVideos

by Weenie


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