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Opinion: how important is weight for a gravel bike?

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Opinion: how important is weight for a gravel bike?

Old 12-18-18, 10:36 PM
  #51  
Metieval
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Originally Posted by gus6464
Seems like there a lot of Ted Kings on here that can extract every ounce of performance from 18lbs vs 25lbs. I dare anyone here with a CX bike to take out my Slate with 650x47s on a gravel road and tell me it's slower.
so why did Ted switch from the Slate to the superX?

because even Ted knows lighter is better.
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Old 12-18-18, 10:48 PM
  #52  
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Originally Posted by Metieval
so why did Ted switch from the Slate to the superX?

because even Ted knows lighter is better.
​​​​​​
because Ted rides what Cannondale gives him.
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Old 12-18-18, 10:53 PM
  #53  
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Originally Posted by gus6464
​​​​​​
because Ted rides what Cannondale gives him.
because on an amateur race, I am pretty sure Ted rides whatever Ted wants to ride. Including the use of aero bars on a CX bike. No matter how many other people cried about it.
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Old 12-19-18, 06:40 AM
  #54  
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Once I hear the word “paceline” I tune out.

Leave that for the Roadies.

EDIT: Just realized the OP was asking about racing.... so yeah, weight is important.

Last edited by Kapusta; 12-19-18 at 09:36 AM.
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Old 12-19-18, 01:14 PM
  #55  
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Pacelines? That is the trick, eh? Do you use your bike as a single purpose bike (Gravel only)? These bikes can be used for almost anything.

I use it as an N-1 bike: one bike to rule them all. So I require:
• An urban bike that is agile enough to thread through traffic, sidewalk cracks, tight corners, jump curbs
• A gravel bike when I just want to get away from it all
• A commuter bike that lets me cover ground at speed
• A mountain bike track when I feel like I need some time in the woods
• A bike that can hang with licensed riders on high end road bikes.
• Something that I can have fun on in a CX race, or gravel race.
• A bike I can ride across the state in one shot.

This bike category can do it all. (I’ll always need my velodrome bike and full suspension bike as those are dedicated purpose machines – but away from the extremes this bike gets the majority of my seat time.)

So, to answer the OP question:
“Do you consider light weight to be important for the possibility of gravel-racing, or even joining in with road events & races?”
Yes. I struggle carrying excess weight up the hills if I’m riding with the racing crowd.
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Old 12-19-18, 05:39 PM
  #56  
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Originally Posted by gus6464
Is paceline on gravel even possible? You're just asking to crash and eat dirt. I've been on a couple gravel group rides and unless we are in a super flat section with just dirt no one is bunched up. Even on gravel rides that have 50% road people don't get dropped. Most of the super strong gravel riders here have the mentality of "if you want to drop people, go ride on road only with skinny tires". Gravel crowd is more chill.
Pacelines have nothing to do with dropping people.

If anything, exactly the opposite is true.


-Tim-
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Old 12-19-18, 05:42 PM
  #57  
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Originally Posted by gus6464
Is paceline on gravel even possible? You're just asking to crash and eat dirt. I've been on a couple gravel group rides and unless we are in a super flat section with just dirt no one is bunched up. Even on gravel rides that have 50% road people don't get dropped. Most of the super strong gravel riders here have the mentality of "if you want to drop people, go ride on road only with skinny tires". Gravel crowd is more chill.
Depends on the surface. Hard pack MMR or rails/trails it is easily doable...as opposed to say pea gravel.

Also depends on the choice of tires employed. People who run GravelKing SKs, tend to not have people draft them.
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Old 12-19-18, 08:33 PM
  #58  
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Originally Posted by chas58
That said, I did to an experiment once - taking a 18lb gravel and 28lb mountain bike on a 3 hour gravel ride. Both had excellent tires, and were pretty close in time for the first 1.5 hours. But, after the 2 hour mark I was just beat carrying the extra weight up our rolling hills, and my time fell off dramatically. I really struggled on the 28lb bike for the last 30 minutes. So, I know I have better endurance on a lighter bike - even if I'm running a slower endurance pace.

How's the position? Sitting upright on a MTB is a ton more aero drag than even a semi-upright endurance position. Which will likely make more of a difference than weight. So will rolling resistance on 35mm semi slicks vs 2" knobbies.

Mostly I ride hardpack, and I can do it on 26mm gravel kings. But 40, 45mm tires give me a lot more flexibility about choosing lines and let me carry more speed because I'm not dancing around rocks and ruts.
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Old 12-19-18, 08:45 PM
  #59  
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Originally Posted by Sullalto
How's the position? Sitting upright on a MTB is a ton more aero drag than even a semi-upright endurance position. Which will likely make more of a difference than weight. So will rolling resistance on 35mm semi slicks vs 2" knobbies.

Mostly I ride hardpack, and I can do it on 26mm gravel kings. But 40, 45mm tires give me a lot more flexibility about choosing lines and let me carry more speed because I'm not dancing around rocks and ruts.
I'm going to say no on both accounts.

With Aero, this was a 3-hour long solo bike ride and honestly we're doing good to average 15 miles per hour. At those speeds Aero means almost nothing.

As for tires, the mountain bike has the lowest resistance tires I've ever seen, at 10 watts per tire they have less rolling resistance in my Supple 40 mm gravel tires.
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Old 12-19-18, 10:31 PM
  #60  
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Originally Posted by chas58
average 15 miles per hour. At those speeds Aero means almost nothing.
When riding solo at 15mph, aerodynamic drag is usually a majority of total resistance on the bike+rider system.

Last edited by HTupolev; 12-19-18 at 10:36 PM.
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Old 12-20-18, 07:31 AM
  #61  
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The question "how important is weight". Stated in other terms is "how important is $$$$ to you". If I have $$$$ to spend, then the weight seems directly proportional on the entire build, including those wheels. Racing may seem to be in the mix, but it really doesn't matter as much as the $$$$ to spend.

Yes, get the most well designed frameset and wheel build for your type of riding. Forget about your lack of skill level.
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Old 12-20-18, 08:04 AM
  #62  
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If you're looking to ride gravel as a race, meaning that you care about finishing position, that you train with intervals and a power meter to get faster, that you see a gravel event as a competition with roadie-type strategy, if you're trying to squeeze every last ounce of performance out of yourself, if you plan on attacking groups on specific hills... then weight might be a factor. To me, even if all of those things are true, bike weight would be one of the last things to focus on. Fitness is most important. Race strategy, being comfortable on the bike (fit, contact points and clothing), good nutrition and hydration strategies, gear reliability, tire selection... all are also far more important than bike weight to me. This is especially true if you're comparing this 19.2 lbs bike to that 18.6 lbs bike... yeah that really doesn't matter at all to me.

It's important to note that this is one interpretation of riding a gravel event, but it's certainly not the only one or even the most popular one. For many people, the entire point of gravel events is to get away from this type of roadie type-A competitiveness.

Last edited by Hiro11; 12-20-18 at 08:07 AM.
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Old 12-20-18, 08:38 AM
  #63  
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When riding solo at 15mph, aerodynamic drag is usually a majority of total resistance on the bike+rider system.
very true above 20mph - aero is the majority of the total resistance. You probably know it goes up exponentially, where friction is linear. At 10mph, aero is trivial and friction is the vast majority of the load.

In my case, I'm in roughly the same aero position on the mountain bike or on my hoods with the gravel bike. Aero wasn't a factor in my test.
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Old 12-20-18, 12:00 PM
  #64  
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Probably less on flat gravel farm roads...
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Old 12-20-18, 12:20 PM
  #65  
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Originally Posted by chas58
very true above 20mph - aero is the majority of the total resistance. You probably know it goes up exponentially, where friction is linear. At 10mph, aero is trivial and friction is the vast majority of the load.

In my case, I'm in roughly the same aero position on the mountain bike or on my hoods with the gravel bike. Aero wasn't a factor in my test.
MTB's have wide flat bars and you are more upright because of the geometry but ok... 2 hours on an MTB will never feel the same as 2 hours on a road bike. The MTB will always beat you up more and it's not mainly the weight. Wide flat bars are not conducive to comfort on a long ride.
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Old 12-20-18, 01:00 PM
  #66  
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Originally Posted by gus6464
MTB's have wide flat bars and you are more upright because of the geometry but ok... 2 hours on an MTB will never feel the same as 2 hours on a road bike. The MTB will always beat you up more and it's not mainly the weight. Wide flat bars are not conducive to comfort on a long ride.
How much time have you actually spent on a mtb?

As someone who has spent a bunch of time on mtbs your comments don't make sense to me.
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Old 12-20-18, 01:15 PM
  #67  
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Weight matters on any bike...mountain, gravel or road.

The heavier it is, the harder it is / more power required to pedal it up the hill. That's just simple physics.
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Old 12-20-18, 01:43 PM
  #68  
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Originally Posted by ogmtb
How much time have you actually spent on a mtb?

As someone who has spent a bunch of time on mtbs your comments don't make sense to me.
That's great but still doesn't change the fact that wide bars on an MTB are not meant for comfort like drop bars on a road bike. Are you seriously trying to argue that drops bars are not more comfortable than wide flat bars on long rides?
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Old 12-20-18, 01:56 PM
  #69  
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Yeah, gus6464s comments don't make much sense to me either. Those two bikes were set up so that one was not more upright than the other, and I've spend I've spend hundreds of miles on the mountain bike it in one go (multiple days), and find it rather comfortable.
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Old 12-20-18, 02:09 PM
  #70  
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Originally Posted by gus6464
That's great but still doesn't change the fact that wide bars on an MTB are not meant for comfort like drop bars on a road bike. Are you seriously trying to argue that drops bars are not more comfortable than wide flat bars on long rides?
It seems that the answer to my question is “no” - you haven’t spent much time on a mountain bike.

I find my drops to be as comfortable as my riser bars on long rides. “Wide bars on an[sic] MTB are not meant for comfort”? That makes no sense.

During long rides on my mtb my upper body movements are much more dynamic than long rides on my gravel bike so if anything I’m less
likely to be locked in the same few positions as a typical gravel ride. Also, every time saddle height changes during my mtb rides my relation to the bars changes - another reason why I’m more dynamic on a mtb.



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Old 12-20-18, 02:38 PM
  #71  
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Originally Posted by chas58
very true above 20mph - aero is the majority of the total resistance.
Riding along a flat road, it's also usually true at 15mph. And quite significantly so. Making air drag a minority of total resistance at 15mph pretty much requires getting into a Graeme Obree tuck and/or running absurdly slow tires.

You probably know it goes up exponentially, where friction is linear.
It goes up cubically, not exponentially. Power lost to aero can be modelled with:
.5 * (air density) * CdA * (velocity ^ 3)

If we assume a rider with a reasonably-svelte CdA of .32, then at 15mph (6.7 m/s) and with a typical sea-level air density of 1.225 we have:
Air resistance = .5 * 1.225 * .32 * (6.7 ^ 3) = 59 watts
That's obviously not very many watts, but this same cyclist is probably doing significantly less than 100W in total to maintain 15mph!

At 10mph, aero is trivial and friction is the vast majority of the load.
On flat road, even at 10mph aero tends to be a pretty large chunk of total resistance. Especially since people tend to lean up more when riding slower.

Most people riding at 10mph on the flats just don't care about whether they're having to pedal at 45 watts or 35 watts, and they certainly don't care enough to bother getting aero.
On a road bike, the question never really comes up, because most folks can do >10mph even while bonking.

In my case, I'm in roughly the same aero position on the mountain bike or on my hoods with the gravel bike.
That's unlikely, especially if your MTB uses typical modern wide bars. Even if you're as low on the MTB as on the gravel bike, you're probably less aero.
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Old 12-20-18, 03:03 PM
  #72  
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Topolev. Good analysis. But again, my example is not hypothetical. This is my specific ride. What drained my energy was taking a heavy bike (and wheels and tires) up rolling hills. I wasn't drained by the aero drag. I can do 100 miles at 15mph on flat ground quite easily on that bike, but the hills will drain me sooner or later on a heavy bike.

If we are going to go down the theoretical rabbit hole - again you are right - at 15mph I'm losing maybe 30 watts if I sit upright. Specifically 160 watts vs 130 watts But again I wasn't sitting upright. my specific bikes had the same amount of tuck and I wasn't using "modern wide bars." Realistically, most calculations show the friction drag graph and the aero drag graph crossing over between 10 and 15mph. In my life - Aero just isn't a big deal at speeds that give me that apparent wind speed. at <18mph I'm looking for any aero advantage I can get. But that's just me. ;-) Again, I'm just sharing my experience. YMMV. ;-)

Back to the OP. Yeah - the weigh made a difference in my endurance. Its been said that wheel weight is twice the penalty as frame weight and having heavier wheels and tires exacerbated the problem on the rolling hills on my route.
Alternatively, if I'm doing a flat ride with no acceleration (on that mountain bike, doing a high speed time trial) - weight doesn't mean anything.
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Old 12-20-18, 07:04 PM
  #73  
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Originally Posted by chas58
As for tires, the mountain bike has the lowest resistance tires I've ever seen, at 10 watts per tire they have less rolling resistance in my Supple 40 mm gravel tires.

Which mountain bike tyres are these?
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Old 12-20-18, 08:14 PM
  #74  
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Originally Posted by ColonelSanders
Which mountain bike tyres are these?
Between 10watts resistance per tire and wind resistance apparently being meaningless at 15mph, I'm fascinated with recent comments in this thread.

certainly is attention grabbing.
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Old 12-20-18, 08:55 PM
  #75  
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Weight matters on a gravel bike as much as it does on a road bike because the effect of gravity is exactly the same. Probably matters more on a gravel bike because there are often steeper grades.
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