Drop Bar MTB Geo

My advice is to not get too hung up on trying to match an existing fit too precisely… I was pretty intent on “mocking” my Crux, and got everything within 4 or 5mm on paper and ordered a range of stems(50mm, 55mm, 60mm, 66mm) and after a single ride started adjusting. In the end I ended up going longer than any of those. I’m not sure of your current gravel bike size, but I actually didn’t size down much and I don’t think I’d want to go any smaller on frame size, partially due to the seat post extension and just aesthetics to a point. I’m on a 54cm Crux, with a 110mm x-17 stem, and now have landed on a 75mm x-25d on the Epic. So despite something like a 50-60mm discrepancy on the measured reaches of the bike I’m not running a proportionally shorter stem. It just handles better, and as product of the much longer front-center and almost inevitably taller stack up front, I think a more stretched out approach is the right one to get some more weight/grip out front. I’m running the same Enve SES Aero 37cm bars on both bikes. The wide handlebar thing is completely lost on me…


Hey great points, I appreciate the recent insights here.

I’m currently on a 56, or a L with a 100mm stem -6 and 78 reach bars with 110 shallow drops. The flair gives me the best of both worlds. I use like almost 40mm in spacers. Maybe it’s my 6’ height.

I got your point on not wanting to size down frames, but I followed your size M as I too ride a L epic evo. A moderate length stem on that M would put me on the numbers you’ve been recommending.

I want to recreate the saddle to bb position, so that’s fixed. Stack is open to dropping a bit. Reach is very open.

Now a size S Epic, however, only reduces wheelbase and reach, both by 25mm. That’s 25mm to give to my stem. Wouldn’t an even longer stem further support your recommendation to stretch out over the front? On the aesthetics front: I, too, am picky, but in this case don’t mind the seatpost length/headtube shape. To be clear, i’m not beating around and playing what if. I just want to rule out the size S, as my window for a free return to Spcycle is closing :slightly_smiling_face:

I think i’m with you on trying to match the fit numbers, they are different bikes and I accept the inherent discrepancies in reach. You seem to ride a much lower stack than mine, I hope the M is still the right choice to build upon.

I def agree with you on bar width, I recently went down to a 40 with tilted hoods and noticed an increase in comfort, down from my 44’s. The flared out drops help me with stability on the rough rocks here in AZ.

I honestly think a small would be ideal. Run a longer stem, get more stable steering, get your front end lower so significantly more aero. Lighter frame. More aero frame. More seatpost exposed so either a longer dropper or more comfort / compliance. Looks better. No compromises with some kind of silly mountain bike 45mm stem (this isn’t an enduro bike!). They don’t do the internally routed frame in a small or that would be ideal. The aim here as I said before is a stable gravel race bike with space for wide tyres, not a terrible hardtail.

The only downside is the smaller central triangle if you need the space for endurance racing and bikepacking bags, I suppose?

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Longer stem = more stability has some meaning on traditional fast-handling road geometries where they try to keep the wheelbase within a range by tweaking the seat and head tube angles. On an off road bike longer stem means shorter wheelbase which is going to be less stable when things get rough. Depending on your courses you might be robbing Peter to pay Paul.

The bigger possible bummer is that the shorter stems don’t give you as much drop at a given negative angle. There’s also less selection in slamstems. But maybe you can find a suitable drop bar with 15mm more drop to make up the difference anyway?

Whether your body can tolerate that extra drop after X hours is another question, but that doesn’t have the numbers people need to base hypotheticals on.


Ditto on the misconception that stem length is the only factor that dictates steering response. For a given frame size that holds some water via actual geometric considerations when you hold factors like input angle or distance consistent [steering input > output].

But too often people ignore the wheelbase & front center impact when discussing this in the wider scope of frame size selection. Assuming the same rider reach & drop from saddle to bars, the front wheel position can have a notable impact on handling in a number of ways.


The additional seatpost length of the S gives you a fair bit of extra compliance as well.

I’m still not entirely sure you will be able to fit the M given this point about your Carbonda:

If you are looking to recreate your saddle-to-bb (setback) and that requires a 25mm setback seatpost you’re already looking at 85-95mm+ more reach that has to be accounted for by the stem, handlebars, or hoods (or if you’re daring, saddle setback itself). However, without knowing your personal morphology it seems at 6’ you should be able to use a longer and lower stem so the M may be well within adjustability range for good fit.

There’s also the use case of replacing a gravel bike and not the goal of making an MTB-to-be-ridden-like-an-MTB with drop bars. It seems hard to argue that the M makes a better fit for this idea given the larger changes to FC/WB/weight distribution over the 696, relative to the S.

This is an interesting problem. I’m not sure which I would pick. The S will provide what I expect a closer match to your 696 as well better adjustability to getting the right fit, however the M may actually ride and handle better depending on your preference and riding style.

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Excellent points.

At the moment, what’s driving me to stay with the M, is that to get the reach feeling “intuitive”/balanced I would be running a 50-70mm stem, which should play well with the trail figure. I may go for that 460 AtoC fork after all.

Going S will have me going for an even longer stem, and that may not play well with the 87-91 trail figure. I do plan to descend and bump through some pretty chunky areas at times.

What really got me understanding the trail/wheelsbase/HTA dynamic were these two videos:

Not to mention, Ben Delaney’s list of test gravel bikes that he enjoyed the handling: The new v4 Stigmata and new Grail are quite in range of my calculated bike.


An update for anyone curious. Rode this around like a balance bike to get a feel for the steering. 454 AtoC, Size M. Super small 32mm tires I had sitting around. 80mm stem I had in my parts drawer, that’s about 35mm of spacers/bearing cap.

The steering is… curious. It steers more gently than the ~80mm trail figure would suggest. I think a 60-70mm stem would liven this up big time. I think of the 2020 BMC URS, and its geo. That rocks a 50mm stem for a shorter reach and approximately the same for most else.

Obviously no cranks in there yet, but I like it. Stable and planted, yet turning input is intuitive.

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3.5cm stack?

You may as well put flat bars on it :wink:

Thanks for the insight! :woozy_face:

Will we be seeing your build any time soon? :grin: I’m curious of your build choices.

Sat on a just a fork and finishing kit and groupset (grx di2 x xtr 11-42 x 40t) and waiting on a frame at the moment (china being slow). Will run my MTB race wheels at the start and once sorted have some gravel 40mm rims laces to some light MTB 24 hole hubs. Umming over integrated aero bars or a two piece.

Cool. What’s the fork? I’d like to see your frame too. I’ve decided to return my RYET fork and go with the Toseek 460 length one.

If I were you, i’d go with two piece bar stem. Given the experimental nature of this built, not to mention the inevitable tinkering to follow your maiden voyage, You’ll be stuck with a one piece bar stem like I did with my gravel bike lol. I found I needed 110 instead of the 100mm I went with.

Yeah - I think a one-piece would be the end plan after I’ve worked out what stem I need for 360/380 c-c top. RYET fork. The only reason to keep two-piece long term would be fitting aero bars for something like Badlands (for which this bike is aimed at). I’m also taking my time as I need to sell some parts first!

In essence I had one CX bike I did everything on (all the way to masters world roads etc) but racing road on 1x was miserable so I’m going to move to having two bikes - a road bike that can take wide-ish tyres and this which can do anything as soon as it gets a bit bumpy. It was that or maybe buy a Kanzo FAST or an Ostro Gravel, but neither available for less than like 5k.

Why have you decided to go RYET->TOSEEK. Does the toseek reduce your spacers (i.e. higher axle crown) or have a significantly different trail or offset? Weight?

I feel your pain on the one bike doing everything, I’m in the same boat.

The fork move is pretty insignificant, mostly an aesthetical change. I like the look of the straight fork leg more. Slightly lighter, and it is 5mm taller in AtoC, so 5mm less spacers. Slightly more relaxed, not sure if i’ll like the effect of that last one. Here’s the numbers.

Aside from the limited tire clearance, I am really liking the geometry system of the new Stigmata. Being 6ft, I would fit their Large, potentially X-Large. I have no experience with that bike’s rid feel, so not sure which.

It is interesting to consider the 69.5 vs my projected bike’s 70.8… obvi there’s more factors at play, but I wonder how that bike does at slower speeds for some tedious technical climbing.

Which frame did you go with for your build (SP-M05 or SP-M06)? I want grx di2 and probably a 38t chainring. I’m actually looking to build an all-purpose one with two wheelsets since I have limited space. I enjoy road riding but only want to get into racing some low-key gravel/xc/cx events in the PNW. Ideally I’d get a set of those nextie rims with 35mm slicks and another wheelset with ~2.2 MTB tires or perhaps Rene Herse knobbies.

M06 is the only one they say will take a 40t (and anything smaller would be a nightmare for general use) so I’m wrangling with them at the moment over clearcoats etc

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Gotcha. If you don’t mind, a few more questions:

  • Did you order directly from Spcycle or on ali?
  • Is this the fork you bought?
  • What is your height/inseam and which size frame did you get?

I’m 6’ with short arms and a ~31 in (78 cm) inseam, so I think the S size makes sense for me. But it’s a bummer that that size only comes with one bottle mount.

some of yall are gonna end up on clown bikes, given the sizing issues from making existing hardtails into these drop bar hybrids :joy:


Have you mounted the chainring yet? I like the SP-M05 for many of the same reasons as you. It’s also odd that it isn’t rated for at least a 38T, since it’s an Epic HT clone which takes a 38T max per specialized’s website.

Ah, I’ve just realised the fatal flaw.

The RYET fork isn’t internal routing compatible - only the toseek one.