GRX FC-RX810 48/31 crank - smaller chainrings?!

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tomh79
Posts: 174
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

If the Shimano page lists the correct information, the GRX 48/31 crankset has a special P.C.D. of 110/80mm - so even smaller than supercompact 120/90mm? Does anybody know if alternative chainrings for this crankset exist? with this chainring diameter, you could easily swap to 26/40 (heavy touring gears)...if you need it.

fattywilliams
Posts: 85
Joined: Wed Apr 10, 2019 6:43 pm

by fattywilliams

Aren't semi compact and compact 110bcd?

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tomh79
Posts: 174
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

Yes - but with 90mm inner. 80mm could be hard to find... "bike components" webshop only lists 4 80mm chainrings - all with 4-arm symmetric. Grx is asymmetric I think.

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prebsy
Posts: 1044
Joined: Tue Oct 23, 2012 10:52 pm
Location: there or thereabouts

by prebsy

So not super helpful but just looking at some theory:

I just did some rough math comparing BCD with minimum ring size. I think ~25T could work. I'm sure some 3rd party will be hard at work on this. Imagine absolute black with the oval on this asym shimano spider, they could probably push down do something like 23T. I'm excited to see what comes out!

tomh79
Posts: 174
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

prebsy wrote:
Wed Apr 15, 2020 6:31 pm
I'm sure some 3rd party will be hard at work on this.
Just had a chat with Absolute Black

Image

looking forward! This 48/31 crank could be a one-does-it-all! 48/31 for road/gravel - and change to 26/40 for touring.

tomh79
Posts: 174
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

any updates on this? checked Wolftooth / AB homepages - no new GRX rings, at least no smaller ones...

jemima
Posts: 270
Joined: Fri Apr 22, 2011 12:36 am
Location: Perth

by jemima

TA - X110 Outer? (down to 42t).

No 80bcd Inners though.
Curve Grovel ti.

tomh79
Posts: 174
Joined: Thu Dec 27, 2018 9:50 pm
Location: Switzerland

by tomh79

yes. but the interesting thing would be to have a 26t inner chainring - which should be possible with 80mm PCD

satanas
Posts: 315
Joined: Sat Jul 04, 2020 5:45 pm

by satanas

TA are now listing rings for GRX - 48, 46, 44, 32, 31, 30, 28T. Smaller should be possible too, down to ~25T, but they're not making them yet. Once the rings are actually available I might well get a set of 44x28, but 42x26 or smaller would be nicer IMHO.

hwyix
Posts: 49
Joined: Mon Jan 03, 2022 12:40 pm

by hwyix

The only place that I see the TA chainrings for sale seems to be scam website :/

tradeinn.com

https://www.sitejabber.com/reviews/tradeinn.com

steveadore
Posts: 386
Joined: Wed Mar 04, 2020 10:01 am

by steveadore

hwyix wrote:
Tue Apr 11, 2023 9:06 pm
The only place that I see the TA chainrings for sale seems to be scam website :/

tradeinn.com

https://www.sitejabber.com/reviews/tradeinn.com
It's not a scam website. I've ordered from them multiple times. The only thing you have to pay attention to is whether the item is in stock, ready for immediate shipping or not (if it's not, it could take a while for shipping). Sometimes they change the status of an item after you order, but in that case you can easily cancel it and get a refund.

I'm not sure why you revived this 2021 thread, btw :)

And to be on topic, I really wish it the RX600 and RX810 chainrings were interchangeable (I would prefer the 46/30 on the hollow forged 810 cranks arms), but as far as I understand, they are not compatible

hwyix
Posts: 49
Joined: Mon Jan 03, 2022 12:40 pm

by hwyix

steveadore wrote:
Tue Apr 11, 2023 9:26 pm
hwyix wrote:
Tue Apr 11, 2023 9:06 pm
The only place that I see the TA chainrings for sale seems to be scam website :/

tradeinn.com

https://www.sitejabber.com/reviews/tradeinn.com
It's not a scam website. I've ordered from them multiple times. The only thing you have to pay attention to is whether the item is in stock, ready for immediate shipping or not (if it's not, it could take a while for shipping). Sometimes they change the status of an item after you order, but in that case you can easily cancel it and get a refund.

I'm not sure why you revived this 2021 thread, btw :)

And to be on topic, I really wish it the RX600 and RX810 chainrings were interchangeable (I would prefer the 46/30 on the hollow forged 810 cranks arms), but as far as I understand, they are not compatible
Because I did "search" on grx 28t chainrings and this thread popped up. The other people here where also interested in smaller grx inner chainring. This way they get notified. Being thoughtfull is not a good thing on this site I guess.


That's really good to know that's a safe website even though they have so many bad reviews. Thanks for the heads up.

steveadore
Posts: 386
Joined: Wed Mar 04, 2020 10:01 am

by steveadore

hwyix wrote:
Tue Apr 11, 2023 9:38 pm
steveadore wrote:
Tue Apr 11, 2023 9:26 pm
hwyix wrote:
Tue Apr 11, 2023 9:06 pm
The only place that I see the TA chainrings for sale seems to be scam website :/

tradeinn.com

https://www.sitejabber.com/reviews/tradeinn.com
It's not a scam website. I've ordered from them multiple times. The only thing you have to pay attention to is whether the item is in stock, ready for immediate shipping or not (if it's not, it could take a while for shipping). Sometimes they change the status of an item after you order, but in that case you can easily cancel it and get a refund.

I'm not sure why you revived this 2021 thread, btw :)

And to be on topic, I really wish it the RX600 and RX810 chainrings were interchangeable (I would prefer the 46/30 on the hollow forged 810 cranks arms), but as far as I understand, they are not compatible

That's really good to know that's a safe website even though they have so many bad reviews. Thanks for the heads up.
I was put off by the reviews too, but then once I needed sth. that only they had in stock, placed my order and received it 3 days later. Since then, I have ordered several times and had no issues, except delays due to items they didn't have in stock (as I said, you can always cancel and modify orders until they actually ship).

I'd be fine with a 30T small ring, but overall I much prefer the 46-30 with a 11-34 cassette to the 48-31. Even with the upcoming 12 speed GRX with 11-36 cassette, I would prefer the 46-30 chainrings. I really don't understand why Shimano is pushing the 48-31. It's not like a 46-11 combination would be easy to spin out.

hwyix
Posts: 49
Joined: Mon Jan 03, 2022 12:40 pm

by hwyix

I got bad knees. I need the cheater baby 28t gear :-) I got hit spliting lanes on my motorcycle. Still can't run or go above say 80% of power pedaling before my knees hurt. Zone 2 & 3 for live for me. lol

steveadore
Posts: 386
Joined: Wed Mar 04, 2020 10:01 am

by steveadore

hwyix wrote:
Tue Apr 11, 2023 10:08 pm
I got bad knees. I need the cheater baby 28t gear :-) I got hit spliting lanes on my motorcycle. Still can't run or go above say 80% of power pedaling before my knees hurt. Zone 2 & 3 for live for me. lol
IF the upcoming 12-speed GRX double crankset were compatible with a 30 small chainrings (sadly, it will be 48-31), with the 11-36 cassette it would basically give you the same easy gear ratios as a 28 small chainring with 11 speed 11-34 cassette, though with bigger jumps at the end of the cassette.

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