Sure, if you stay with moderate wide gravel tires, wide aero rims like the Nextie AGX 45 makes total sense. I have those and run it either with 40 mm wide Schwalbe G-One R or even better as my road bike with 34 mm Schwalbe Pro One which then measure 36 mm on them. Perfectly adhering to the 105 % rule and really good riding and cornering.
But, if you pair them with much wider tires like e.g. 2.20 Conti RaceKings it would probably not be of any (or only miniscule) effect. Nevertheless I pondered lacing up my Nexties with Boost hubs just for shitsân giggles to throw on my Dropbar Exceed.
In any case: I did some aerotesting and also reviewed and showed research and 3rd party testing from e.g. Swiss Side who did some nice wind tunnel tests with regard to gravel tire widths and âknobnessâ as effects for drag with different rims.
Stem length has nothing to do with twitchy handling, other than as a side effect it changes the front-rear wheel weight distribution. Check out Peter Verdoneâs blog for a more in depth look.
Iâve found the exact opposite on my drop bar MTB, a 100mm stem moves weight distribution forward improving front wheel grip and making the steering âfasterâ. same bike and bar with a 40mm stem has a rearward weight distribution which feels more stable.
So why do I chose drop bars and why are they set up the way you see in the photos?
a) beware the sag! The front of my bike drops around 2 cm when I sit on it. I run 2,9 cm drop (i.e. my saddle is 2.9 cm higher then my hoods)
b) but indeed, thatâs a bit less than on my gravel / all road / endurance road bike (a No 22 Drifter). Why? Because I wanted a bit more overlook and âuprightnessâ for steeper descends.
c) most important: I donât like flatbars for riding long. For actual pedaling and making kilometers. I simply find them uncomfortable and not versatile enough.
d) I also become much more aero. Not from the drop. No, from the much narrower hand position. Thatâs not the main reason but really, riding on flatbars (even on mine which I cut narrower) is like being like a brake parachute in the wind. Literally. So itâs not like wanting to get more aero with dropbars. Itâs more like: trying to avoid that more than obvious disadvantage of flatbars.
e) Hoods are not everything. I really do use my drops also. And frequently.
Stem length directly influences the lever angle of the bar. For a given bar width, a longer stem will mean a smaller change in wheel angle for the same movement in handlebar.
That might not exactly influence stability but it does influence why you might want a short vs longer stem, aside from weight balance!
More progressive MTB geo tends to even longer top tubes. But also to respectively shorter stems. So reach wise (provided the way someone is to sit on a bike is relatively similar agressive or less agressive intended compared to 2 hypothetical gravel and mountain bikes) itâs a wash.
But indeed - stem length is but one parameter in the steering and I would argue (well, I havenât invented it, thatâs just common understanding and physics) that other parameters like head tube angle, fork offset and rake etc. are way more important. And the stem is but the icing on the cake. And on top of that just one part of the parameter of said icing which is not the stem length but the effective reach (influenced by handle bar geometry) and the resulting effective steering arc (all can be found in my linked article on the theory of steering / handling flat vs drop bar).
But nevertheless - an important parameter none the less. So by going for shorter and shorter stems modern mtbs as well as in that direction going modern gravel bikes do take options away from us.
Because:
a) reach is a combination of the stem and the sweep and rise of a flat bar or the sweep and the reach of a drop bar.
If you want freedom to choose the handlebar / hand position of your choice or dial in the steering of your bike perfectly to your taste you will want the option to go longer as well as shorter with your stem.
Now - if your chosen MTB already comes stock with a super short 45 mm stem your options are pretty cut short in going shorter. That would be my main gripe with such a super current mtb. But it could feel and ride perfectly for you if thatâs your thing and you test it and find it spot on for you.
My hardtail is Shimano right now. My road/gravel bikes are SRAM.
The problem/cost is the frame and fork are both post-mount. All the new dropbar lever/caliper kits are flat-mount. Bare levers are available, but harder to find discounted and then you have to figure out which hoses/fittings to use. The Wolftooth PM-FM adapter is neat, but forces a +20mm rotor and I donât want to run 180mm rotors on this bike. A.S.S. in Canada has adapters that donât force the +20 - I need to measure the frame to see if theyâll work (they have much tighter tolerances).
AXS does make the conversion pretty easy - no cables, no pull ratio problems, etc. Even if I donât go to drop bars, Iâll likely go to AXS (from Shimano 11 speed) later this season for ease of geared/SS conversion (I use the bike for SS racing at a local dirt crit series).
I really need to steak my neighbors custom Zukas monstercross for a week and see if I even like the style before committing any money to a conversion.
This is the article I used to build my Specialized Chisel into a Drop Bar bike. This thread kind of cracks me up with the amount of nerdery going to make hard tails into effectively gravel bikes. They arenât. The Drop Bar MTB is an effective if youâre looking for long term comfort over long distances on challenging and changing terrain. It wonât be as aero as a gravel bike, and it most certainly will take more effort to get it up to speed, but the narrower form, and more ergonomic position than flat bars make it fast and comfortable. Two things that are paramount when spending all day, multiple days or weeks on a bike. Yes you have too look at specs and geo here for a bit but it comes down to just trying it. Iâve got thousands of miles clocked on mine on everything from black diamond Pisgah Gnar to flat and fast bike paths in Florida. Itâs pretty well dialed.
the âexchange kitâ option is a good way to get just the brifters (includes hose as well). then you can choose whatever calipers you want. (sram has a webpage which goes through different brake caliper hose compatibility).
Bit confused - you disagreed with me then restated my point back to me . As you say, any modern MTB will have geometry such that picking the same size as you would ride with a flat bar will put you in a pickle when you switch to drops (because it has reach numbers designed partially around a sub 50mm stem but more to create stability when descending). Therefore, size down.
Or donât - but I will - especially so I can run a decent size -25 degree stem.
Oh, hmm - maybe I got irritated by the big numbers of your given stem lengths compensations. In the end, if a rider shouldnât end up like on a strechting bank, there is only so many centimeters a top tube can get longer while a ânormalâ stem is getting shorter. If we talk 11 cm stems (for S or M sized bikes and people) thereâs basically only 7 cm the stem can get shorter and the top tube longer (if you are thought to sit somewhat similarily on said bikes).
(In this viewing we can omit flat vs drop by roughly compensating broader grip to narrower grip and added dropbar reach). But not 8-9 cm.
But yes - indeed. We seem to be on the same page now. Chalk it up to written communication and the state the recipients mind is at times 2 steps ahead.
Err, you mean me? Sorry - the TR form can be quite ambiguous in terms of seeing at a glance what post is meant to be a reply or follow up to which post before it. But maybe thatâs just me.
If you mean my post Iâm scratching my head why youâd connect top tube length as a parameter of, I assume, the theory I lay out in the steering article I referred to earlier. But rest assured - no, Iâm not.
Itâs just a number and like any other geometry number can inform you but has to be considered in relative dimension to all other geometry parameters. And even then itâs only a first (sound) guestimation how a bike really rides and feels. But the proof is always in the pudding, i.e. actual riding.
But actually I often get asked about top tube lengths and from people worrying about either having to shorten the stem of a flatbar bike dramatically to put on a drop bar (because of reach) and nearly equally as often worrying about having the lengthen the stem to somehow counter the feared massive amplified âTwitchinessâ. Neither is the case and why that is and how you can arrive at a good starting place stem length wise is precisely the reason I wrote that article (and draw schematics) in the first place.
The geometry is messed up for the Epic, itâs bottom bracket height is calculated incorrectly probably due to how the bike had to be input in order to display the diagram. BB Height should be around 310-320mm.
For a general comparison like this, itâs also worth fixing the tire size on the Epic WC, and use the âalign groundâ setting in the top right corner⌠It helps you visualize the stance of both. These two are worlds apart⌠I wish they werenât, but they are. As mentioned earlier, I wanted to justify a similar build, but its just so niche, and might be compromising on too many fronts. Headlines: a full 100mm longer front center is going to tough to overcome, weight distribution wise. This doesnât even account for the fact youâll be a full 60mm higher in the front end, exacerbating the problem of getting some weight over the front tire. With the 40mm-60mm stem youâll be running combined with the 4d slacker heat tube angle, turning is just not going to be confidence inspiring with drop bars. The trail numbers are pretty far apart, and it would feel pretty wonky at low speeds.
The epic wc is going to have the front wheel much further out, and that will take a lot of attention to make it turn well. You will need to weight the front end harder. I find I have issues with this kind of thing, because with longer front ends Iâm fairly prone to making drop bars slip and rotate down.
If you donât get enough weight on the front it will feel wayward and prone to understeer
. As you say, any modern MTB will have geometry such that picking the same size as you would ride with a flat bar will put you in a pickle when you switch to drops (because it has reach numbers designed partially around a sub 50mm stem but more to create stability when descending). Therefore, size down.
