Enduro/AM - The Weight Game

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Enduro/AM - The Weight Game
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flag R-M-R
Posted: Mar 2, 2019 at 20:34 Quote
scjeremy wrote:
That’s mathematically very interesting and compelling argument but I did a long enough stint of “enduro” riding on a 35 lb bullit and I’ll never again climb anything over 32ish lbs. 30 ish is even better and still tracks just fine bombing back down.

You're comparing an ancient bike with ancient parts to modern bikes. I should hope there's more to it if you look beyond the weight; otherwise, we might as well put light parts on our bikes from the '90s because the only thing keeping them from being as good as new bikes is the weight! Wink

The kinematics of the Buillit were quirky and the ergonomics would be completely unacceptable on a modern bike. Tire rolling resistance has dropped greatly - and perhaps you had DH tires on that old beast?

As an example, Enduro magazine recently tested fourteen enduro bikeshttps://enduro-mtb.com/en/best-enduro-bike-you-can-buy/. The two lightest bikes received the lowest climbing scores, primarily due to their ergonomics. Whether you trust magazine tests or believe they're simply advertisements for the highest bidders is up to you. Having done some marketing, I can tell you we would never consider paying for anything when our money could result in negative press, i.e. if we weren't the highest bidder. Solo reviews and press releases make sense for paid content, though.

Another example: modern cars weigh more than old cars and use less fuel, yet the new cars are faster and have more traction.

Weight isn't everything - sometimes, it's the least significant variable in the equation.
flag theweaz
Posted: Mar 2, 2019 at 20:52 Quote
I would argue it depends where all that weight is added. If you were adding it to pretty much the bottom bracket then yea you probably wouldn’t notice it much. Adding it further out from the center of the bike is going to definitely cause handling changes.

I know for a fact that when I put a cushcore in the rear wheel the weight was very noticeable, and that’s only 200 grams.
flag R-M-R
Posted: Mar 2, 2019 at 21:03 Quote
theweaz wrote:
I would argue it depends where all that weight is added. If you were adding it to pretty much the bottom bracket then yea you probably wouldn’t notice it much. Adding it further out from the center of the bike is going to definitely cause handling changes.

I know for a fact that when I put a cushcore in the rear wheel the weight was very noticeable, and that’s only 200 grams.

Yes, the energy loss due to perimeter wheel mass is about double that of mass located at the middle of the wheels or on the chassis.

Wheel mass - regardless of location on the wheel - contributes to a less favourable sprung:unsprung mass ratio. Bad stuff all around, but sometimes unavoidable.
flag chickendog
Posted: Mar 2, 2019 at 21:13 Quote
I don't believe weight is the biggest factor in effort put out , tires , tire pressure , suspension efficiency ,pedal bob , climb switch etc . You have all your settings dialed in hardpack and then do the same trail when muddy or rolling through frozen leaves and you have much more perceived effort , there is more resistance ,you realize if you were moving less weight it would be easier but once you lose some weight it is still the same situation of less resistance on hardpack vs frozen leaves ,lighter is better ,definitely to your benefit to lose the weight but riding the same trails throughout the seasons will prove to you that weight , if reasonable to start with , is not usually the biggest factor in holding you back from your previous personal best , if your bike still weighs the same , you are used to that weight but that does not always translate to your effort because of conditions . So suspension settings and tire combinations , pressures , will come in to play .All these things are more evident with these modern bicycles than they were on the old freeride type monster trucks,






.
flag scjeremy
O+
Posted: Mar 2, 2019 at 21:14 Quote
R-M-R wrote:
scjeremy wrote:
That’s mathematically very interesting and compelling argument but I did a long enough stint of “enduro” riding on a 35 lb bullit and I’ll never again climb anything over 32ish lbs. 30 ish is even better and still tracks just fine bombing back down.

You're comparing an ancient bike with ancient parts to modern bikes. I should hope there's more to it if you look beyond the weight; otherwise, we might as well put light parts on our bikes from the '90s because the only thing keeping them from being as good as new bikes is the weight! Wink

The kinematics of the Buillit were quirky and the ergonomics would be completely unacceptable on a modern bike. Tire rolling resistance has dropped greatly - and perhaps you had DH tires on that old beast?

As an example, Enduro magazine recently tested fourteen enduro bikeshttps://enduro-mtb.com/en/best-enduro-bike-you-can-buy/. The two lightest bikes received the lowest climbing scores, primarily due to their ergonomics. Whether you trust magazine tests or believe they're simply advertisements for the highest bidders is up to you. Having done some marketing, I can tell you we would never consider paying for anything when our money could result in negative press, i.e. if we weren't the highest bidder. Solo reviews and press releases make sense for paid content, though.

Another example: modern cars weigh more than old cars and use less fuel, yet the new cars are faster and have more traction.

Weight isn't everything - sometimes, it's the least significant variable in the equation.
Good point about the 15 yo bike but I’ve never ridden a 35 pound modern bike so can’t really campare. I just did however get a new bike that’s almost exactly 1.5lbs heavier than my last bike and I can’t notice it at all. Even on the first few rides just not noticable at all.
flag R-M-R
Posted: Mar 2, 2019 at 21:20 Quote
scjeremy wrote:
Good point about the 15 yo bike but I’ve never ridden a 35 pound modern bike so can’t really campare. I just did however get a new bike that’s almost exactly 1.5lbs heavier than my last bike and I can’t notice it at all. Even on the first few rides just not noticable at all.

Go up a hill with a water bottle. Now remove the water bottle. Tell me whether it made much difference. That's about 1.5 lbs.

Duct tape a 2 L bottle to the bike for the experiment to feel what 4.4 lbs does. You may not even notice.
flag chickendog
Posted: Mar 2, 2019 at 21:30 Quote
R-M-R wrote:
scjeremy wrote:
Good point about the 15 yo bike but I’ve never ridden a 35 pound modern bike so can’t really campare. I just did however get a new bike that’s almost exactly 1.5lbs heavier than my last bike and I can’t notice it at all. Even on the first few rides just not noticable at all.

Go up a hill with a water bottle. Now remove the water bottle. Tell me whether it made much difference. That's about 1.5 lbs.

Duct tape a 2 L bottle to the bike for the experiment to feel what 4.4 lbs does. You may not even notice.
that is a good way to prove the point, let out some pressure in your tires . or soften your suspension , I believe you will notice the difference
flag Axxe
Posted: Mar 2, 2019 at 21:44 Quote
R-M-R wrote:
Axxe wrote:
Your rant assumes simple linear dependency. Biomechanical systems are highly nonlinear. 1% matters.

As long as a lower gear is available and you can maintain your balance while climbing, this relationship is essentially linear. Non-linearity would be a bigger issue if we were riding singlespeeds and the extra mass forced us to put out more power; when we have the option to gear down, we can assume equal power output and equal contractile force in the muscles.

It is not just riding up on a smooth road. It is accelerating and going over obstacles.

It is absolute possible to tell a lighter bike in a blind test.
flag R-M-R
Posted: Mar 2, 2019 at 22:30 Quote
Axxe wrote:
R-M-R wrote:
Axxe wrote:
Your rant assumes simple linear dependency. Biomechanical systems are highly nonlinear. 1% matters.

As long as a lower gear is available and you can maintain your balance while climbing, this relationship is essentially linear. Non-linearity would be a bigger issue if we were riding singlespeeds and the extra mass forced us to put out more power; when we have the option to gear down, we can assume equal power output and equal contractile force in the muscles.

It is not just riding up on a smooth road. It is accelerating and going over obstacles.

It is absolute possible to tell a lighter bike in a blind test.

Sometimes, not always. And a lighter bike isn't always faster. If weight was kept constant between two bikes and one had more rolling resistance, it would obviously be slower. Or if the only difference was drivetrain friction, the one with more friction would be slower. So, how much weight, friction, rolling resistance, etc. is required to balance out the other variables?

I maintain the weight vs. speed relationship is close to linear. This puts an upper bound on the speed differences due to weight at (Δweight) / (total weight), which will be in the range of low single digit percentages for realistic weight differences. There are several other factors that, over a typical range, contribute more to speed differences. Even if the relationship were highly non-linear, a typical difference of about 1% in weight is still going to produce a small speed difference.

I'm not saying weight has literally zero effect - I was being provocative in how I phrased it; I'm saying it's one of the least significant factors, despite receiving the most attention.
flag moferenc
Posted: Mar 2, 2019 at 22:43 Quote
In our culture "Weight is the sign of reliability".
https://youtu.be/lX0MB7pJtKs
flag seraph
Posted: Mar 2, 2019 at 23:56 Quote
Your car analogy is misplaced. Weight is an insignificant factor when comparing old to new cars. New cars are faster and handle better largely due to their advanced traction control, braking, and electronic control systems. They're programmed to compensate for their curb weights.
flag chickendog
Posted: Mar 2, 2019 at 23:59 Quote
newer bikes use their geometry numbers to compensate for their curb weights
flag R-M-R
Posted: Mar 3, 2019 at 0:18 Quote
seraph wrote:
Your car analogy is misplaced. Weight is an insignificant factor when comparing old to new cars. New cars are faster and handle better largely due to their advanced traction control, braking, and electronic control systems. They're programmed to compensate for their curb weights.

Acceleration is force / mass, so mass is definitely a factor! These are the laws of physics and there's no such thing as "programmed to compensate". You could switch off every traction control device on a modern car and it will still be faster and more efficient in every way than an old car. Mass matters, but other advancements matter more - just as with bikes.
flag tom666
Posted: Mar 3, 2019 at 1:26 Quote
I think people generally sweat weight too much. If you're more than 5 or 10kg overweight you should definitely think about removing the log from your own eye before pointing out the spec in somebody else's (your bike's). Also if you're not riding several times a week (I barely get out whilst I'm at University) I would wager weight makes about zero difference compared to if you just got in better shape.

That said,

I switched from DT Swiss M1900 wheels to Stans flows on Hope Pro4. Heavier wheelset.

I also changed tires from Onza Ibex 2.4 (880g) to Maxxis DHR2 2.4 (~1100g).

I felt the shit out of that. So much slower on road and on climbs. The extra rotating weight is super noticeable. If I had hill climb PBs on Strava I think I would be struggling to beat them.
flag badbadleroybrown
Posted: Mar 3, 2019 at 3:43 Quote
seraph wrote:
Your car analogy is misplaced. Weight is an insignificant factor when comparing old to new cars. New cars are faster and handle better largely due to their advanced traction control, braking, and electronic control systems. They're programmed to compensate for their curb weights.
You do realize newer cars were faster than older cars long before traction control or electronics right? Traction control and all that BS just makes new cars faster under shit drivers... it's there to compensate for a lack of skill, not curb weight.

 


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