XC Marathon Fully with... Drops? Advice?

[MovinMamba]

Hi everyone, I'm looking to build a gravel bike that might be on the verge of over biking.

I saw XC FS frames used at races like Leadville and was wondering how dumb would it be for a roadie like me to build up the same kinda bike with a drop bar? I.e Dylan Johnson style with FS (He used a hardtail xc).

I'm assuming reach issues with a 30-40mm stem could be solved to get a similar geo to most gravel bikes, so far I've been looking at the Light Carbon 918?

Considering there isn't too much information and I've been a roadie for the past 3 years, is this a really really dumb idea?
Am I missing something completely? Any advice is appreciate thank you I love you all mwah mwah

[wfl3]

Really the biggest issue I see using an MTB frame as the base for a gravel bike is the limited front chainring size if you try to keep the recommended chain line.

Maybe going 2x solves this?     

[MovinMamba]

Sorry I'm somewhat of a mtb newbie, but why is it limiting? I mean I know the LCFS918 is listed as 36t but is this typically a bottoming out or frame issue? Ideally I could run 40t 1 by.

And if it was 2 by you mean to say that it would clear the frame better because it's offset? Do you think I could just run a single chainring then if I just yolo it and leave only the big ring on?

Appreciate your help and here is one of my Inspos

https://www.instagram.com/p/CxOiucSuq0s/?hl=en

[Peak district XC]

I think you main issue would be clearance on the frame rear triangle I think 38t would be possible on 918, but wouldn’t be ideal clearance wise. X2 I don’t think would work as the spacing would be terrible for chainline. You could see what a what gearing you could do with 36/38t with a non standard 12speed rear cassette to give closer higher speed ratios (Shimano make one for the old x2) but your going to be limited by the smallest cog for the highest gear. Would something like as you mention a HT mtb or maybe better the new gravel frame with a small amount of rear travel and put a front fork in.

[jefflinde]

dengue makes a full suspension gravel frame.  built around a 100/100mm travel.  http://m.dengfubikes.com/index.php?s=/229.html

[acedeuce802]

Ha, I just responded to you on reddit.  Here's how my old Monstercross bike started life, I did a few rides with a fork and messed around with different tires, but mostly had it set up as a 29er gravel bike https://chinertown.com/index.php/topic,2837.msg20146.html#msg20146

Chainring clearance is limited by the chainstay.  MTB's have the wide tires that road bikes don't, so the chainstay flares outward where the tire is.  Bigger chainring means you need to push that little bump out rearward or inward, which means either making chainstays longer or limiting tire clearance.  In reality, 36t is probably the largest you'll find on a full squish.  The FM199 I built from had a bunch of chainring clearance, but it's a hardtail.  36t front and 10t rear is pretty tall gearing though.  Remember than 29er's are worth about 2t more speed than 700c, and 10t is 10% over 11t, so a 36/10t on 29er is similar to 42/11t on 700c.  Not enough gear to win a gravel race, but more than enough for XC racing and fine for most gravel stuff.  34/10t on my MTB's is enough to get around 30mph before I spin out and tuck.

[jefflinde]

One other thing is to look for 0° or 3° offset chainrings.  I run shimano cranks and Pass Quest makes some in both variations. You could flip a 3° around so it moves outward to give you more clearance. 

[MovinMamba]

Do you guys think that the chainring sizing could be overcome by going with a DUB wide bb? extra 2.5mm. Or is that something that all MTBs have standard to begin with?

[Ludo]

Look at the Scott HT, SP cycle  has a copy and I think it allows 40T chainring

[numberzero]

I have briefly tested a fully mtb with a drop bar.
For me the drop bar doesn't allow to use the full potential of the bike and i always felt frustrated not to have a flat bar for more control. I lost the fun of the gravel and the ability of the MTB...
It wasn't a fun machine.

If i was to build a suspended gravel, i will go with max 50mm travel, big rolling tyres and road/gravel geometry.

[jefflinde]

Do you guys think that the chainring sizing could be overcome by going with a DUB wide bb? extra 2.5mm. Or is that something that all MTBs have standard to begin with?

You will run into the same issue no matter how you move the chainring out and that is really poor shifting and excessive cross chaining on the low gears.  I am not familiar with the DUB stuff but you will be limited by the spindle length either way. If you make the bb 2.5mm wider then the crank spindle needs to do the same.  You would be better off getting a crankset to fit and using chainring offset.  I think they even go up to 5 or 6mm for the cinch style ones.  Am am sure the 3 bolt or 8 bolt ones are the same.  This was done a lot in the fat bike world to get better chain lines.

[darkening]

You should go size down, or a couple of sizes down to get a reasonable long stem. With short stem(shorter than 60mm), you will get terrible bike handling(very nervous) on a narrow dropbars.

And try to get a frame with the max chainstay length as possible. It will help with chaincross issue.

You can buy a boost cranks and/or chainrings with 0 offstet to not rub the chainstays.

[MovinMamba]

You should go size down, or a couple of sizes down to get a reasonable long stem. With short stem(shorter than 60mm), you will get terrible bike handling(very nervous) on a narrow dropbars.

I'm curious, so if I go for relatively wide bars, i.e. 440m wide drops with 550mm flare and a 60mm stem it starts getting to XC territory right? (narrow xc that is), but also the ultrawide drop bar has additional reach which flat bars don't? If I'm honest the reason I dont wanna ride flats is because ergonomically I feel much more comfortable long distances on drops than on flats

ill defo check the boost cranks! 

[acedeuce802]

Wide bars will make the reach problem even worse.  Have you ridden wide drops before?  Personally, I'm very comfortable on 40cm gravel bars with slight flare, and 740-760mm flat bars with some backsweep.  The flat bars I ride most have 11deg backsweep where most bars have more like 6-7, helps keep the wrist angle a bit more in check.  44cm drops with medium flare (Ritchey Venturemax, don't remember the flare) were very uncomfortable for me.  I've ridden a bike around the parking lot with PNW bars before, maybe they were the 48cm's, and it just felt ridiculous to me.  You may have a different experience though.  It seems to me like you should just be on a gravel bike that takes over 50mm tires and put a gravel fork on it.

[MovinMamba]

I have ridden 420mm flared gravel bars but tbh i was more in aw of the comfort of the grx hoods…

but Yea i think the reality is setting in that im probably gonna need both a fully XC and a gravel bike … was hoping i could combine the two but here we are

n+1 afterall