Square Taper to Hollowtech II Spacers?
10-03-23, 10:31 PM
#1
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Square Taper to Hollowtech II Spacers?
I ordered the following crank and bottom bracket:
https://bike.shimano.com/en-US/produ...-RX600-10.html
with 175 mm crank arm length.
https://bike.shimano.com/en-EU/produ.../BB-RS501.html
shell with of 68 mm
The bottom bracket came with no spacers.
This article says I need: A 68mm or 83mm bottom bracket shell needs two of the 2.5mm spacers on the drive (chainring) side and one 2.5mm spacer on the non-drive side.
https://off.road.cc/how-many-spacers...wtech-sram-gxp
My chain line is 47mm
I guess I need to buy some spacers, but can someone explain what the spacers do actually. Drive I understand for chain line, non drive is confusing, other than it moves the crank out.
https://bike.shimano.com/en-US/produ...-RX600-10.html
with 175 mm crank arm length.
https://bike.shimano.com/en-EU/produ.../BB-RS501.html
shell with of 68 mm
The bottom bracket came with no spacers.
This article says I need: A 68mm or 83mm bottom bracket shell needs two of the 2.5mm spacers on the drive (chainring) side and one 2.5mm spacer on the non-drive side.
https://off.road.cc/how-many-spacers...wtech-sram-gxp
My chain line is 47mm
I guess I need to buy some spacers, but can someone explain what the spacers do actually. Drive I understand for chain line, non drive is confusing, other than it moves the crank out.
10-04-23, 12:43 AM
#2
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the NDS moves the CUP out,to meet the NDS crankarm at the proper place.
i swap spacers back and forth until the crank is both aligned at the proper Chainline, Both arms are equa-distant from the chainstays at the pedal area, and the crankset is also firmly in place against the bearings.
the combination isn't always as the directions state.
and there SHOULD have been three spacers in the box with the BB assy. 1mm, 1.5mm, 2.5mm, if the BB was a "68 or 73mm" type... if not, slap that sucker in and see if it all fits well..
I, and i'd guess, many other mechanics save the spacers when not needed... your local shop should have some, if actually required for your frame.
i swap spacers back and forth until the crank is both aligned at the proper Chainline, Both arms are equa-distant from the chainstays at the pedal area, and the crankset is also firmly in place against the bearings.
the combination isn't always as the directions state.
and there SHOULD have been three spacers in the box with the BB assy. 1mm, 1.5mm, 2.5mm, if the BB was a "68 or 73mm" type... if not, slap that sucker in and see if it all fits well..
I, and i'd guess, many other mechanics save the spacers when not needed... your local shop should have some, if actually required for your frame.
Last edited by maddog34; 10-04-23 at 12:57 AM.
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10-04-23, 06:49 AM
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Why are you taking advice from a MTB article to install gravel cranks on a gravel bike? MTBs have different chainline and spindle lengths than gravel bikes.
Here's the exploded view for your crank and that BB:
https://dassets.shimano.com/content/...X600-4579B.pdf
No spacers.
Here's the exploded view for your crank and that BB:
https://dassets.shimano.com/content/...X600-4579B.pdf
No spacers.
10-04-23, 12:14 PM
#4
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Why are you taking advice from a MTB article to install gravel cranks on a gravel bike? MTBs have different chainline and spindle lengths than gravel bikes.
Here's the exploded view for your crank and that BB:
https://dassets.shimano.com/content/...X600-4579B.pdf
No spacers.
Here's the exploded view for your crank and that BB:
https://dassets.shimano.com/content/...X600-4579B.pdf
No spacers.
10-04-23, 01:54 PM
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Here is my take on this:
You are planning on installing a GRX crank. However the bottom bracket you have chosen is designed for a Tiagra road crank. GRX cranks have a lot in common with mountain bike cranks in terms of chainline. They have longer spindles to allow a wider chainline than a road crank. The bottom bracket you chose is incorrect for the crank you bought. The correct bottom bracket would have included the spacers you will need
You are planning on installing a GRX crank. However the bottom bracket you have chosen is designed for a Tiagra road crank. GRX cranks have a lot in common with mountain bike cranks in terms of chainline. They have longer spindles to allow a wider chainline than a road crank. The bottom bracket you chose is incorrect for the crank you bought. The correct bottom bracket would have included the spacers you will need
10-04-23, 02:34 PM
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FWIW I recently installed a GRX 46/30 11 spd crank on a road bike with 68mm BB. I had a Di2 FD and the FD was both
too high on the 'braze-on' mount and would not extend out far enough to reach the 46t ring. Solution was to use an FD dropper which lowers the
FD about 6mm or so on the built in FD mount ( available from either FSA or Amazon) and machine a solid $12 5/8"
diameter 6061 aluminum bar (Home Depot) into 8 2.5mm thick washers to put between the chainrings and the DS spider. This moved
the chainrings inboard enough for the FD to reach the 46t ring. Mods worked perfectly.
too high on the 'braze-on' mount and would not extend out far enough to reach the 46t ring. Solution was to use an FD dropper which lowers the
FD about 6mm or so on the built in FD mount ( available from either FSA or Amazon) and machine a solid $12 5/8"
diameter 6061 aluminum bar (Home Depot) into 8 2.5mm thick washers to put between the chainrings and the DS spider. This moved
the chainrings inboard enough for the FD to reach the 46t ring. Mods worked perfectly.
10-04-23, 05:40 PM
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Here is my take on this:
You are planning on installing a GRX crank. However the bottom bracket you have chosen is designed for a Tiagra road crank. GRX cranks have a lot in common with mountain bike cranks in terms of chainline. They have longer spindles to allow a wider chainline than a road crank. The bottom bracket you chose is incorrect for the crank you bought. The correct bottom bracket would have included the spacers you will need
You are planning on installing a GRX crank. However the bottom bracket you have chosen is designed for a Tiagra road crank. GRX cranks have a lot in common with mountain bike cranks in terms of chainline. They have longer spindles to allow a wider chainline than a road crank. The bottom bracket you chose is incorrect for the crank you bought. The correct bottom bracket would have included the spacers you will need
WHY ARE YOU POSTING FALSE INFORMATION WHEN THE RIGHT INFORMATION IS UNDER YOUR FINGERTIPS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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10-04-23, 07:14 PM
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and not everyone knows that GRX cranksets are intended for wider frames with 73mm BB width.... or can be fitted to a 68mm frame by using the included Crank Spindle spacers...... OR by using the Included Spacers that come with a new 68-73mm HTII BB, and fit between the frame and cup(s).
calm down.. sheesh.
i'd guess that item #5 is 2.5mm thick.... times two.
10-04-23, 07:43 PM
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+1 you can force It a bit with this setup using a couple 1-2 mm crank spacers, 1mm petal space either for tread line and a couple 1mm axel spacers and be good. End of the day It's a 1-4mm drive total 1-2mm offset pretty easy to correct for on nearly any bike.
10-05-23, 02:08 AM
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See: item #5 (x2), in the diagram you posted a link to.
and not everyone knows that GRX cranksets are intended for wider frames with 73mm BB width.... or can be fitted to a 68mm frame by using the included Crank Spindle spacers...... OR by using the Included Spacers that come with a new 68-73mm HTII BB, and fit between the frame and cup(s).
calm down.. sheesh.
i'd guess that item #5 is 2.5mm thick.... times two.
and not everyone knows that GRX cranksets are intended for wider frames with 73mm BB width.... or can be fitted to a 68mm frame by using the included Crank Spindle spacers...... OR by using the Included Spacers that come with a new 68-73mm HTII BB, and fit between the frame and cup(s).
calm down.. sheesh.
i'd guess that item #5 is 2.5mm thick.... times two.
Last edited by choddo; 10-05-23 at 02:12 AM.
10-05-23, 06:40 AM
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See: item #5 (x2), in the diagram you posted a link to.
and not everyone knows that GRX cranksets are intended for wider frames with 73mm BB width.... or can be fitted to a 68mm frame by using the included Crank Spindle spacers...... OR by using the Included Spacers that come with a new 68-73mm HTII BB, and fit between the frame and cup(s).
calm down.. sheesh.
i'd guess that item #5 is 2.5mm thick.... times two.
and not everyone knows that GRX cranksets are intended for wider frames with 73mm BB width.... or can be fitted to a 68mm frame by using the included Crank Spindle spacers...... OR by using the Included Spacers that come with a new 68-73mm HTII BB, and fit between the frame and cup(s).
calm down.. sheesh.
i'd guess that item #5 is 2.5mm thick.... times two.
Sheesh, so much misinformation.
10-05-23, 12:55 PM
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and no one has mentioned facing the bottom bracket of the 73mm width frame.... it has been done to other folks' bikes.
the seals in the "tik-Tube" video increase "bearing drag" and trap grit on the bearing's seals,... they are on many GXP cranks...they fail to prevent water or grit intrusion, and , once removed, the bearings last longer.... the rider noticed the reduced drag even in a short test blast through the neighborhood...the "GXP grunge" took three more months to appear.. Scott CX Team bike... bike was never pressure washed, and regularly ridden in wet/muddy conditions, AKA: Oregon Cyclocross Events and rough gravel roads, some trails, and a linear trail with lousy pavement.
Last edited by maddog34; 10-05-23 at 12:58 PM.
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10-05-23, 01:38 PM
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ok then.. how thick is the 24mm ID "little washer" that's not a washer?
and no one has mentioned facing the bottom bracket of the 73mm width frame.... it has been done to other folks' bikes.
the seals in the "tik-Tube" video increase "bearing drag" and trap grit on the bearing's seals,... they are on many GXP cranks...they fail to prevent water or grit intrusion, and , once removed, the bearings last longer.... the rider noticed the reduced drag even in a short test blast through the neighborhood...the "GXP grunge" took three more months to appear.. Scott CX Team bike... bike was never pressure washed, and regularly ridden in wet/muddy conditions, AKA: Oregon Cyclocross Events and rough gravel roads, some trails, and a linear trail with lousy pavement.
and no one has mentioned facing the bottom bracket of the 73mm width frame.... it has been done to other folks' bikes.
the seals in the "tik-Tube" video increase "bearing drag" and trap grit on the bearing's seals,... they are on many GXP cranks...they fail to prevent water or grit intrusion, and , once removed, the bearings last longer.... the rider noticed the reduced drag even in a short test blast through the neighborhood...the "GXP grunge" took three more months to appear.. Scott CX Team bike... bike was never pressure washed, and regularly ridden in wet/muddy conditions, AKA: Oregon Cyclocross Events and rough gravel roads, some trails, and a linear trail with lousy pavement.
Who said that the OPs bike is 73?
GRX is road spec, 68mm bikes.
11-21-23, 10:36 AM
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Finally did the conversion. The square taper actually seized and forced me to replace. After looking at the bottom bracket at 68mm and my frame at 68mm it would make no sense to add any spacers as the the plastic sleeve inside the bottom bracket would not have engaged on the non-drive side. Had to move the front derailleur up and re-adjust. Only did a test ride as the weather has been bad for cycling. What has changed is that I used to have to use the third ring on the cassette from the smallest gear to back pedal to oil or clean the chain. Otherwise, the chain would want to shift to a higher gear. Now I have to use the fourth for that not to happen when back pedaling on the bicycle stand.
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12-19-23, 08:41 PM
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Wanted to add one more outcome. In purchasing the crank I made the mistake of selecting the 170mm crank length. After noticing this I did some internet searching and found various methods which include measuring your inseam to get the best crank length for your body. The calculation for me was 170mm or a little smaller. So, I installed the 170mm and gave it a try. I ride at least 30 miles or more each ride and after two days of 35 and 40 miles my right knee started aching. I even upped my saddle 5mm because of the shorter length. After a few more rides, the knee was not liking it, so I bit the bullet and purchased the same crank in 175mm length. Installed that and noticed the relief in my knee during the second ride. I never thought 5mm shorter would affect my comfort, but it did.
"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world." - Archimedes
"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world." - Archimedes
Last edited by themp; 12-19-23 at 08:47 PM.
12-20-23, 01:28 AM
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Finally did the conversion. The square taper actually seized and forced me to replace. After looking at the bottom bracket at 68mm and my frame at 68mm it would make no sense to add any spacers as the the plastic sleeve inside the bottom bracket would not have engaged on the non-drive side. Had to move the front derailleur up and re-adjust. Only did a test ride as the weather has been bad for cycling. What has changed is that I used to have to use the third ring on the cassette from the smallest gear to back pedal to oil or clean the chain. Otherwise, the chain would want to shift to a higher gear. Now I have to use the fourth for that not to happen when back pedaling on the bicycle stand.
12-20-23, 05:32 PM
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12-21-23, 02:26 AM
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