Monstercross-esque Chisel
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Was thinking of getting a chisel and putting a 40 mm travel fork on it with drop bars and trying to get it close to a monster cross 29er.
Two issues I would like advice on:
Max tooth chainring I can run on a chisel and other similar hardtails that may be able to take a bigger ring?
Would reducing the travel from the stock fork affect the headtube strength of the bike?
Two issues I would like advice on:
Max tooth chainring I can run on a chisel and other similar hardtails that may be able to take a bigger ring?
Would reducing the travel from the stock fork affect the headtube strength of the bike?
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- Posts: 736
- Joined: Sat Jul 24, 2010 9:41 pm
Most mtb hardtails max out at 36t on the front. That's a non starter in my book and honestly just get a good gravel frame, the Chisel will be a series of compromises for no benefit.
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Sorry for late (and not so complete) answer. Any thing between 2011. till (probably) 2020. You can go even crazy and get Niner RKT 9 RDO or hardtail version NINER AIR 9 RD (both frames support front derailleur) but they are both boost frames. Or go get something from China (135/142mm). China frames are 350e with transport (and paid customs). BXT frame is ok frame for that money.
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I've done similar to what you're looking to do, although with a Epic HT. I set out to make a Crux, but with clearance for 2.4" tires...
You can definitely run larger chain rings than the 36t they state. I'm actually running a "gravel" crankset, in the form of the Force Wide with Quarq Spindle as I prefer a narrow Q factor. I have ran both 38t(0mm offset) and 36t(3mm offset) chainrings. With these lower offset chainrings, the chain ends up in the same place as it would be on a DUB mtb crank, as SRAM build a ton of offset into their road/gravel 1x rings(something like 8mm by my measurement of a stock 40t ring). You have a ton of wiggle room on chainline, and there are dozens of chainring options to adjust accordingly. When I was stocking up on parts I was worried about chainstay clearance, so I started with the 38t 0mm offset, which turned out to leave more than 6mm of clearance between the chainstay and the ring, hence the move to a 3mm offset ring. I have no doubt that a 40t or 42mm 0mm offset ring would fit easily.
Fork wise, I'd be hesitant to go with a suspenion gravel fork for two reasons... First off, you're then stuck running a mixed wheelset, with a boost rear hub, and a non-boost 12x100 front hub. This is just a pain, unless you're lacing wheels up from scratch, but still. Second reason is just the really short axle-to-crown. I was able to source the shortest rigid boost fork I've seen, with an a-c of 454mm on my build shown here. I crunched all the numbers ahead of time, and knew what this would do to my bottom bracket drop, head tube angle, seat tube angle, reach, etc... Rule of thumb is that about 30mm of fork length shortening results in a full degree of head tube angle steepening. I landed at 70.9 HTA, and 75.0 actual STA as measured. This is squarely in the gravel bike territory, and was exactly what I was looking for with my build. A 40mm Rudy fork has a a-c of only 435, so you'd be at about 71.7 HTA, which is getting steep.
Also don't overlook the ability to get the bars where you need them. These most recent Epic and Chisel frames have really long reach figures, and its worth avoiding a 40mm stem if you can. I sized down from what I'd normally run with flat bars, and still have to get a bit wacky with the stem angle to get the stack low enough. I've played around with several lengths and angles, and am still figuring out where I want to land. Currently on a 75mm x -25d stem.
The craziest part of this build, which I should probably post a thread on, is the weight... its lighter than my Crux and lighter than some road bike builds on here...
17.95lbs / 8.14kg complete as shown, with pedals, cages, garmin mount, power meter, etc...
Initial buildup w/ heavier wheels/tires, SL7 stem, and 38t XX SL ring.
You can definitely run larger chain rings than the 36t they state. I'm actually running a "gravel" crankset, in the form of the Force Wide with Quarq Spindle as I prefer a narrow Q factor. I have ran both 38t(0mm offset) and 36t(3mm offset) chainrings. With these lower offset chainrings, the chain ends up in the same place as it would be on a DUB mtb crank, as SRAM build a ton of offset into their road/gravel 1x rings(something like 8mm by my measurement of a stock 40t ring). You have a ton of wiggle room on chainline, and there are dozens of chainring options to adjust accordingly. When I was stocking up on parts I was worried about chainstay clearance, so I started with the 38t 0mm offset, which turned out to leave more than 6mm of clearance between the chainstay and the ring, hence the move to a 3mm offset ring. I have no doubt that a 40t or 42mm 0mm offset ring would fit easily.
Fork wise, I'd be hesitant to go with a suspenion gravel fork for two reasons... First off, you're then stuck running a mixed wheelset, with a boost rear hub, and a non-boost 12x100 front hub. This is just a pain, unless you're lacing wheels up from scratch, but still. Second reason is just the really short axle-to-crown. I was able to source the shortest rigid boost fork I've seen, with an a-c of 454mm on my build shown here. I crunched all the numbers ahead of time, and knew what this would do to my bottom bracket drop, head tube angle, seat tube angle, reach, etc... Rule of thumb is that about 30mm of fork length shortening results in a full degree of head tube angle steepening. I landed at 70.9 HTA, and 75.0 actual STA as measured. This is squarely in the gravel bike territory, and was exactly what I was looking for with my build. A 40mm Rudy fork has a a-c of only 435, so you'd be at about 71.7 HTA, which is getting steep.
Also don't overlook the ability to get the bars where you need them. These most recent Epic and Chisel frames have really long reach figures, and its worth avoiding a 40mm stem if you can. I sized down from what I'd normally run with flat bars, and still have to get a bit wacky with the stem angle to get the stack low enough. I've played around with several lengths and angles, and am still figuring out where I want to land. Currently on a 75mm x -25d stem.
The craziest part of this build, which I should probably post a thread on, is the weight... its lighter than my Crux and lighter than some road bike builds on here...
17.95lbs / 8.14kg complete as shown, with pedals, cages, garmin mount, power meter, etc...
Initial buildup w/ heavier wheels/tires, SL7 stem, and 38t XX SL ring.
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- Posts: 41
- Joined: Mon Jul 24, 2017 6:32 pm
I would love a breakdown of this. I have an epic that’s still flat bar but set up for big gravel races like Leadville. For lower elevation though, I decided to see what I could get away with on a zero offset chainring, and in fact, I managed to fit 44t, which lets me keep up with friends on their gravel bikes.Upcountry wrote:I've done similar to what you're looking to do, although with a Epic HT. I set out to make a Crux, but with clearance for 2.4" tires...
You can definitely run larger chain rings than the 36t they state. I'm actually running a "gravel" crankset, in the form of the Force Wide with Quarq Spindle as I prefer a narrow Q factor. I have ran both 38t(0mm offset) and 36t(3mm offset) chainrings. With these lower offset chainrings, the chain ends up in the same place as it would be on a DUB mtb crank, as SRAM build a ton of offset into their road/gravel 1x rings(something like 8mm by my measurement of a stock 40t ring). You have a ton of wiggle room on chainline, and there are dozens of chainring options to adjust accordingly. When I was stocking up on parts I was worried about chainstay clearance, so I started with the 38t 0mm offset, which turned out to leave more than 6mm of clearance between the chainstay and the ring, hence the move to a 3mm offset ring. I have no doubt that a 40t or 42mm 0mm offset ring would fit easily.
Fork wise, I'd be hesitant to go with a suspenion gravel fork for two reasons... First off, you're then stuck running a mixed wheelset, with a boost rear hub, and a non-boost 12x100 front hub. This is just a pain, unless you're lacing wheels up from scratch, but still. Second reason is just the really short axle-to-crown. I was able to source the shortest rigid boost fork I've seen, with an a-c of 454mm on my build shown here. I crunched all the numbers ahead of time, and knew what this would do to my bottom bracket drop, head tube angle, seat tube angle, reach, etc... Rule of thumb is that about 30mm of fork length shortening results in a full degree of head tube angle steepening. I landed at 70.9 HTA, and 75.0 actual STA as measured. This is squarely in the gravel bike territory, and was exactly what I was looking for with my build. A 40mm Rudy fork has a a-c of only 435, so you'd be at about 71.7 HTA, which is getting steep.
Also don't overlook the ability to get the bars where you need them. These most recent Epic and Chisel frames have really long reach figures, and its worth avoiding a 40mm stem if you can. I sized down from what I'd normally run with flat bars, and still have to get a bit wacky with the stem angle to get the stack low enough. I've played around with several lengths and angles, and am still figuring out where I want to land. Currently on a 75mm x -25d stem.
The craziest part of this build, which I should probably post a thread on, is the weight... its lighter than my Crux and lighter than some road bike builds on here...
17.95lbs / 8.14kg complete as shown, with pedals, cages, garmin mount, power meter, etc...
Initial buildup w/ heavier wheels/tires, SL7 stem, and 38t XX SL ring.
I’m contemplating going this route, or maybe even using a formula speed lock so I can switch between flat and curly bars.
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2019 carbon Orbea Alma OMR+Spirit fork setup could take a 2x.
Small size 29er frame -with their Spirit fork atc- is 380/597mm.
That 380mm reach -for example- isn't too bad for a dropbar [reach] conversion.
There are a few short-reach flared dropbars out there also.
Curve Grovel ti.
Sorry to just get back to this but did you have to use any spacers or modify the chainline? New to off road cycling coming from road and am curious.
I'll chime in... That picture is from ServiceKoers.cc, and I'm guessing he just shared it... They use "custom" chainrings, that they have made by The Mechanic-parts. They're simply 0mm offset rings. There are several brands doing the same, including Sram themselves wth the XX SL Transmission rings, which are in fact backwards compatible with Eagle chains.
If I put a 55mm CL crank on a 52mm CL frame like the Chisel, would it be an issue?Upcountry wrote: ↑Thu Dec 21, 2023 3:40 pmI'll chime in... That picture is from ServiceKoers.cc, and I'm guessing he just shared it... They use "custom" chainrings, that they have made by The Mechanic-parts. They're simply 0mm offset rings. There are several brands doing the same, including Sram themselves wth the XX SL Transmission rings, which are in fact backwards compatible with Eagle chains.
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