Subcompact cranksets compatible with Shimano RS500 92mm pressfit BB?
07-22-19, 06:02 PM
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Subcompact cranksets compatible with Shimano RS500 92mm pressfit BB?
I have a Trek Checkpoint ALR5 and I'm wondering what my options are to replace the crankset with a subcompact double (30/46), hopefully without replacing the BB? Trek's specs list the bike has having a Shimano RS500 92mm press-fit BB, and the OEM cranks are Shimano 105 R7000 (for an 11sp drivetrain). I'm partial to budget-friendly brands like Praxis and FSA. Do I have any options here?
If not, what BB can I switch to that would give me the most options?
FWIW, I'm aware of the AbsoluteBlack oval chainrings, and while the idea of using those with my 105 crank is appealing, I've heard they are quite finicky to get shift adjustment dialed in for, and they strongly recommend only using Dura-Ace chains. I'm willing to spend the extra money on a crankset upgrade if that means I can retain easier shift adjustability.
If not, what BB can I switch to that would give me the most options?
FWIW, I'm aware of the AbsoluteBlack oval chainrings, and while the idea of using those with my 105 crank is appealing, I've heard they are quite finicky to get shift adjustment dialed in for, and they strongly recommend only using Dura-Ace chains. I'm willing to spend the extra money on a crankset upgrade if that means I can retain easier shift adjustability.
07-24-19, 11:46 AM
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Measure the bb shell—I thick the listed spec is wrong and it's actually bb86.5 which is Shimano press fit road, Bb92 is shimano press fit mtn. Praxis and fsa both make crank/bb combos for bb86.5 in subcompact configurations. Sugino also makes a subcompact crank that will fit in the shimano bb, but it's really pricy. There's also https://absoluteblack.cc/oval-road-c...-for-110-4bcd/ if oval sounds interesting and you can swallow the style. Were I you I'd get https://shop.fullspeedahead.com/en/energy-modular-bb386evo-crankset-4297 plus the bb86.5 386evo bb to match.
07-24-19, 12:17 PM
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Lots of options here: https://www.bikeforums.net/fifty-plu...road-bike.html
Shimano is releasing its own 46/30T crank, (GRX), and it is fairly inexpensive ($150) compared to many of the boutique options.
Shimano is releasing its own 46/30T crank, (GRX), and it is fairly inexpensive ($150) compared to many of the boutique options.
Last edited by Cyclist0108; 07-24-19 at 12:23 PM.
07-24-19, 02:24 PM
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https://www.trekbikes.com/internatio...alr-5/p/22630/
Any road crankset with a 24 mm spindle diameter should work without the OP having to change the bottom bracket.
07-25-19, 10:38 AM
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Leave the BB alone and get a set of Shimano GRX cranks in 46/30. Done, and they are relatively, for Shimano, cheap.
With luck your present FD will slide down low enough to fit the chainring and handle the 16t difference. It will need to
be lowered ~0.3". Your present BB is compatible with any 24mm crankset, ie ALL Shimano cranksets for the last 12-15yrs.
My FD7000 works fine with a 48/32 crankset.
With luck your present FD will slide down low enough to fit the chainring and handle the 16t difference. It will need to
be lowered ~0.3". Your present BB is compatible with any 24mm crankset, ie ALL Shimano cranksets for the last 12-15yrs.
My FD7000 works fine with a 48/32 crankset.
Last edited by sch; 07-25-19 at 10:43 AM.
07-25-19, 04:15 PM
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Leave the BB alone and get a set of Shimano GRX cranks in 46/30. Done, and they are relatively, for Shimano, cheap.
With luck your present FD will slide down low enough to fit the chainring and handle the 16t difference. It will need to
be lowered ~0.3". Your present BB is compatible with any 24mm crankset, ie ALL Shimano cranksets for the last 12-15yrs.
My FD7000 works fine with a 48/32 crankset.
With luck your present FD will slide down low enough to fit the chainring and handle the 16t difference. It will need to
be lowered ~0.3". Your present BB is compatible with any 24mm crankset, ie ALL Shimano cranksets for the last 12-15yrs.
My FD7000 works fine with a 48/32 crankset.
08-16-19, 01:21 PM
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Just as a follow-up, I ended up going the GRX crank and FD route, and posted about it in another thread. Also, I measured the BB shell with digital calipers and it came out to around 87mm, so it is indeed a BB86.5 BB, not the 90 as Trek specifies on their US website.
