Swapping bars and groupsets

Hey friends, wanted to get some takes on the feasibility of an idea I have to optimize my small bike fleet.

Right now I have an eight-year-old hardtail set up 1x10 with a mix of SLX, XT, and deore components, and a slightly newer gravel bike with 1x11 SRAM Apex, and mechanical disc brakes (:-1:). In the spring I am getting a new carbon MTB, my first full suspension (yay!), but I also have a road and a triathlon bike, and I don’t have the storage or spousal permission to own five bikes. I like the gravel bike frame, but I hate the mechanical disc brakes, and my profession (piano tuning) has given me early arthritis in one thumb joint, which is making drop bars off road a bad experience.

So, here’s what I want to do: move all of the Shimano mtb components along with the flat bars from my hardtail onto my gravel bike. Is there any reason I can’t do this? My thought is I would move the bars and Apex stuff onto the hardtail, and sell that bike for super cheap, or even maybe donate it if no one wants a drop bar mtb with mechanical disc brakes. The hardtail is QR and the gravel bike is thru-axle, but I’m thinking that shouldn’t matter since I’m not swapping wheel sets? I am a beginner when it comes to diy bike work, but I am interested in learning more skills. Thanks!

Should work fine, as long as the disc caliper mounts are the same. Most likely your MTB has post-mounts, but the gravel bike may have flat-mounts (much smaller calipers). You can get adaptors to fit post-mount calipers to flat-mount frames and forks. The geometry may not be quite right for flat bars so you might want to change the stem, but if I were you I’d set it up with what you’ve got then work out if you want to go taller/more upright (or the opposite).

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Besides the caliper mount, the MTB frame is going to be about 60mm+ longer than the gravel bike. So it’ll be an awkward looking bike. Maybe try to clean house and just sell both bikes? Going flat bar gravel bike with Shimano MTB, you’ll probably have a hassle getting the stem length right, but you can measure that ahead of time. As a HT MTB, it’ll suck because you’re over the front tire, meaning you’re at risk for going over the bars on a medium size bump.

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Yes, good point. The MTB is post mount, and the gravel is flat mount. Do I understand correctly that I can adapt post mount calipers for a flat mound frame but not the other way around? Meaning the brakes won’t work on the bike I am trying to get rid of.

That may be what I end up needing to do, but I don’t think I will be able to get enough for both bikes to pay for the level of flat bar gravel bike I would like. So I want to fully explore this before going down that road.

Will it be any sketchier than it is now with the drop bars? I will be primarily using it on pavement and gravel (hauling the kids, commuting, exploring etc), with only occasional single track when the psychos I ride with pure pressure me into it.

What’s wrong with the current HT for gravel duty? Slap a bigger ring on there and different tires?

It won’t be sketchy, that’s BS. Where your weight is with respect to the wheelbase and the rear tire is more important. I once had a Tarmac that was sketchy all hell above 30mph with the stock setup. If you’re getting rowdy, you want the front axle in front of your bars when you look down, so the front has leverage to lift you rather than throw you off the front. If you’re more over the rear tire, the bike will feel more nimble. Where the pivot is for the front tire is doesn’t really matter as much as where the bars are relative to the wheel (within reason here). Bar flex, wheel flex, etc also play a part here.

I’d just pull the bar off your current bikes and give it a quick test if you’re concerned. Zip tie the shifters to the frame and mount it up really quick. Just make sure you can grab a brake.

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If you buy a new 11-speed sram mtb shifter and derailleur, you can keep the 11speed cassette and chainring. With flat bars, no issue at all having shimano brakes and sram shifters.
(Actually, I think if you might be able to buy a shimano 11 speed shifter, and keep the existing 10 speed shimano derailleur, and still use the 11 speed cassette. Someone might be able to confirm?)

Otherwise, you probably can’t move the crankset over (likely different size BB, but you could move the chainring.

I can’t comment on the geometry and whether it’d be weird, but don’t think so. Best to give it a test before committing to it though.

I’d sell the leftover frame and bike parts as components, could even make more than with selling a full bike.

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I have definitely considered this! The gravel frame is several pounds lighter, and more modern with thru-axle. Plus it’s a 56cm, which fits me better than the medium mtb frame.

Good idea! I will likely do this.

Great thoughts! Maybe I’ll hang onto both cassettes initially and keep that option open. I wasn’t planning to swap cranks or chainrings anyway.

Also good call about parting it out rather than selling a complete bike, especially since I can’t mount the gravel bike’s calipers onto the ht frame anyway.

Update: I ended up doing just this. Sold the gravel bike for way more than I could have sold the hardtail. Put on a rigid fork, gravel tires, and upgraded the drivetrain to 11s gx with a 40t chainring and an 11-46 Sunrace cassette. I love it and am so happy with this choice. Thanks for the advice!

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Good deal! So cool when we hear about success stories like this. Thanks for circling back to share the results :smiley:

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