Sussy vs rigid MTB fork aerodynamics + weight

How much do you figure you give up in aerodynamics and weight with a suspension fork vs. a rigid fork on your hardtail? Let’s say you’re doing a 5 stage 350 mile gravel race in Oregon with an average speed of something in the neighborhood of 12-13mph average. Let’s figure…the enve rigid fork vs. a sid. Let’s also figure 1600 vs. 800 grams so it’ll save a bit under 2#. FWIW let’s figure the heavy floppy thing on top of the bike is 6’ 3" and 195#'s.

Is it even worth considering? Is it possible it’s faster? Or is it more like…take your $650 and buy fast tires and a road suit then maybe spend the rest on beer?

I appreciate your facts and/or opinions :slight_smile:
Joe

  • Unless you are fighting wind at 5+mph, aero is largely negligible at that speed.
  • Weight is interesting, but you’d really need to know the elevation change and even road pitches to start to figure if weight is that beneficial.
  • Do the tires regardless. This is likely beneficial and could make more difference than any aero or weight savings with the mileage involved.
  • Aero suit or well fitting jersey and shorts are smart too at the least, since you are relatively large, and the body is actually the largest drag part of the aero equation.
  • Couple that with the potential for body position of things like aero bars for more narrow and low position, I’d say you are better on tires and body position & gear than anything.
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You also need to factor in how much faster you will be on descents with a suspension fork, as well as the conserved energy form not getting the crap beat out of you everyday across 5 days.

I think it is pretty well-established doctrine that a suspension fork lets you be faster / safer / more comfortable vs. a rigid fork.

As Chad noted, focus on fast tires and other opportunities to improve aerodynamics (including potentially an aero road lid).

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Consider the aero difference of the forks to be essentially zero. The bike is one of the worst places to look for aero gains. Your body position is like 80% or more. Wheels, helmet, skin suit are most of the rest. Frame/fork is peanuts. It matters only when everything else is optimized.

So first focus on rolling resistance.

Next, get your body in a tuck on the fast decents.
Aero bars and A dropper post may be your best bets, since I assume in Oregon you will have some lengthy descents.

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Agreed. Unless it’s an especially smooth gravel I’d pick the suspension would be much faster and much more forgiving.

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Take the $650 and get some Continental Race King Protection tires…they test as fast as the fastest gravel tires on bicyclerollingresistance.com. Then get a Specialized Evade helmet, Castelli San Remo speed suit, and some inner barends for the MTB. Have fun and good luck!

I was kinda thinking the Rene herse tire

I rode trans Iowa v 12 on the schwalbe big one (on a voodoo 29r hard tail) and the Rene herse tire looks even more comfy and faster too. I did the 400k 24 hours of cumming with flat bars, inboard bar ends, and aero bars and that worked pretty well (on a surly cross check) I’m a fan of your advice!

Something about the hard tail just seems so much slower than a road or gravel bike…I’m not sure why though. On gravel at 13 mph the big soft tires should be faster and the mob should absolutely kill the gravel bike on any even somewhat rough descent.

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