GRX 1x advice

9 replies · 1,675 views

Deepsprayj
22 posts
#1Aug 2, 2021, 12:42 PM
I really loath 2x setups and I would like to switch my Praxis 2x crank out for a GRX 1x crankset. My question is if I need to replace the bottom bracket? I was looking at the Giant website and the Revolt Advanced 2 has an Praxis M24 BB86, press fit and the 1x version of the bike just says Shimano press fit. I would think that it should just be a straight swap but I was hoping to make sure before I drop the money and try to order the crankset.
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imwjl
304 posts
#2Aug 2, 2021, 1:32 PM
With GRX and so much hard to find, have you looked to see if your OEM crank has a 1x conversion with good chain line? I've liked Wolf Tooth rings like that for not having shims or spacers.
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Deepsprayj
22 posts
#3Aug 2, 2021, 3:52 PM
It looks like praxis does indeed have a 1x ring. I will have to see if it is compatible with the crank when I get a chance. Mine looks different from their 1x crank but maybe it will still be a possibility. I think wolf tooth and some others make DM 3 bolt rings so I might be able to go that route.
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stu
646 posts
#4Aug 2, 2021, 4:22 PM
This doesn't directly address your question but another possibility is to use a 2x setup with closely-spaced chainrings. You would still have a front derailleur but with a difference of 6T or less both the front and rear would shift very smoothly. I have a Praxis 2X crankset which takes 110 BCD rings, those are available in almost every size between 34T and 53T.
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Shurlock
40 posts
#5Aug 2, 2021, 6:26 PMedited
Yes, replace the BB to go from Praxis to Shimano cranks.

You can replace the Press Fit with a BB86/92 threaded shell made by Wheels and then you have a screw in BB that supports the 24mm spindle of the GRX set.

I just swapped out the 2x Praxis to a 1x Shimano GRX 810 on a 2021 Giant Revolt Advanced 2 and am happy to have solved some chainline issues in doing do. It is not an inexpensive fix. Went with a bigger cassette so had to grab a Wolf tooth link as well.

Better (and less money) is to buy a 1x set-up from the jump. The Revolt Advanced 1 is $400 more than the 2 and that is quite a few schmeckles less than one will spend on the conversion.
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Deepsprayj
22 posts
#6Aug 3, 2021, 1:18 AM
Shurlock wrote:
Yes, replace the BB to go from Praxis to Shimano cranks.

You can replace the Press Fit with a BB86/92 threaded shell made by Wheels and then you have a screw in BB that supports the 24mm spindle of the GRX set.

I just swapped out the 2x Praxis to a 1x Shimano GRX 810 on a 2021 Giant Revolt Advanced 2 and am happy to have solved some chainline issues in doing do. It is not an inexpensive fix. Went with a bigger cassette so had to grab a Wolf tooth link as well.

Better (and less money) is to buy a 1x set-up from the jump. The Revolt Advanced 1 is $400 more than the 2 and that is quite a few schmeckles less than one will spend on the conversion.

Yeah the revolt 1 was not available when I got mine. At least not anywhere close to me. My local shop had the 2 on the floor so I got it. So is it really that much more? GRX 600 crank is 150, bottom bracket, casette, and wolf tooth hangar thing can't be much more than $250. Giant puts a 11-42 on a grx 810 derailleur which I have so the wolf tooth part may be redundant. The praxis 1x crankset is 250 if you can find one and then I wouldn't need the bottom bracket if I went that route.
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Shurlock
40 posts
#7Aug 3, 2021, 9:29 AMedited
If you already have a decent cassette that does lower it by almost $100 but I would swap out that cheap Praxis M24/BB86 if you are doing the cranks, even if you stay with Praxis. That BB is the weakest part of the system here. Real cheapo stuff.

There are two different GRX 800 derailleurs. One is for the 1x (GRX 812) and the other is for the 2x (GRX 810) . The 2x derailluer (which comes OEM on this bike) cannot really handle the 11-42 cassette without a Wolf link (they are cheap). You will have issues in the two lowest gears without the link. On the Advanced 1 they use a longer cage on the derailleur and that allows it to work the 11-42.

It was an engineering mistake by Giant to use the Praxis Crankset on this bike. The Shimano GRX sets Q factor is 2.5mm wider than road cranks and due to the wider crank and chainline GRX cranks should be used with a GRX front derailleur.

Real BB: $90
GRX 800 1x Crank $250
11-42 Cassette: $90
Wolf Tooth: $30
Labor: ?
Tools:?

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Deepsprayj
22 posts
#8Aug 3, 2021, 10:01 AMedited
Shurlock wrote:
If you already have a decent cassette that does lower it by almost $100 but I would swap out that cheap Praxis M24/BB86 if you are doing the cranks, even if you stay with Praxis. That BB is the weakest part of the system here. Real cheapo stuff.

There are two different GRX 800 derailleurs. One is for the 1x (GRX 812) and the other is for the 2x (GRX 810) . The 2x derailluer (which comes OEM on this bike) cannot really handle the 11-42 cassette without a Wolf link (they are cheap). You will have issues in the two lowest gears without the link. On the Advanced 1 they use a longer cage on the derailleur and that allows it to work the 11-42.

It was an engineering mistake by Giant to use the Praxis Crankset on this bike. The Shimano GRX sets Q factor is 2.5mm wider than road cranks and due to the wider crank and chainline GRX cranks should be used with a GRX front derailleur.

Real BB: $90
GRX 800 1x Crank $250
11-42 Cassette: $90
Wolf Tooth: $30
Labor: ?
Tools:?

Did you use the road version or the mtb version for the grx conversion with the wolf tooth link?
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Shurlock
40 posts
#9Aug 8, 2021, 5:59 PM
Mtb
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Deepsprayj
22 posts
#10Aug 10, 2021, 11:16 PM
Thnx
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