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well, a 36lb hardtail my end, rides better than my lighter full sus and my mates lighter hardtails, i say just mtfu and get on with it 😉
the thread's about weight, trent 🙄
GW it got pulled, I remain mystified as to why.
"It does. A whippet flat back position uses different muscle groups to a sit up and beg one. That's why gym exercise bikes are cack. Also why time trial bikes have steep angles."
sit up and beg vs. TT bike maybe. A few degrees on mtbs I disagree.
I think geometry does make difference, I've had fairly similar weight hardtails before but one was horrible up hill because the geometry put you in a bad position in relation to the pedals and it felt like I was using different muscles.
A bike with DH geometry will feel different efficiency wise, even if it's the same weight as an xc geometry bike. On mtb's you get bikes with head angles that are different by as much as 8 or 9 degrees, which is more than just a few degrees? Short or long top tubes will make a difference. It all affects how much you can expand your rib cage when breathing surely?
That's why gym exercise bikes are cack
The upright position is less efficient. But consider that they generate no motion which means they are 0% efficient!
why do all these threads just turn into black or white disagreements when the world is grey
The world is pretty grey this morning, quite right 🙂
If you scroll back though, you will see that I did in fact acknowledge that both weight and geometry are both important 🙂
But consider that they generate no motion which means they are 0% efficient!
I meant in terms of power generated versus perceived exertion.
A few degrees on mtbs I disagree
I don't. My bike feels quite different if I move the saddle forward or backwards. To pedalling style and weight distribution - your weight is not only further forwards but you have to raise the saddle if you move it forwards which puts your COG higher. And if it's full sus, there's less weight over the back wheel which changes how the suspension behaves and how you can set it up....
I love details 🙂
My bike feels quite different if I move the saddle forward or backwards. To pedalling style and weight distribution - your weight is not only further forwards but you have to raise the saddle if you move it forwards which puts your COG higher. And if it's full sus, there's less weight over the back wheel which changes how the suspension behaves and how you can set it up....
Precisely none of which has been established to make the bike go faster.
I think it's a reasonably well accepted fact that Cynic-Al [i]thinks[/i] weight makes sod all difference, but in reality 5lbs is a lot and the weight (along with other factors such as geometry and tyres) will make it noticeably slower.
GW is right. I'm going to add "sciencefact" to that, so I guess that's this argument shut.
I remember mols posting his power output calcs... on a thread about climbing times / rider / bike weight???
On the the same thread I posted average commute times for the bikes I had run over the last 5 or so years. Two of those bikes were similar weight hardtails - a lightly built L / 19.5" Pace RC305 and a similar weight 21" Airborne Lucky Strike. Both weighed in at between 23-25lbs depending on wheel / tyre combos fitted at any given time.
Airborne always felt way faster than the Pace, except on more technical descents, where the very long stretched out geometry became too prone to over the bars moments...
Commute timings bear this out too. Airborne was 5-10 mins per hour quicker than the Pace.
I'm not arguing all for geometry - just countering the "geometry doesn't affect efficiency" trolling 😉
5lbs difference on the bike is huge - 5lbs on the body / in the Camelback will be more tiring over the day, but doesn't affect the ride in any way the same manner.
So why am I [i]less[/i] knackered after riding my 34lb AM bike over a long distance than I am on my 28.5lb XC bike?
Pedal efficiency has a lot to do with it.
Luke, your opinion trumps mine, even though mine is backed up by tests?
Nice to see cyclists still regard the bicycle as independent of any of the laws of physics...
Don't talk to me about laws of physics! Studied them for four years! What I am doing is applying those laws to the handling and performance of our bikes.
Out of interest, what do you consider 'bugger all difference' to be? On a 10 minute fire-road climb, if someone gets to the top 30s ahead of someone else, that's a fair old difference when you're racing your mates, but it's only 5% in quantitative terms...
Say 5lb of 25 (bike) + 155 (rider) is 2.75%, a direct gain on climbs, where say you spend 40% of your time in an xc race, making you 1.1% faster, 1:12m faster in a 2 hour race.
[i]What I am doing is applying those laws to the handling and performance of our bikes[/i]
...and describing the effect in terms of 'massive' or 'huge' or 'the size of an elephant'....
...and convieniently ignoring the huge camelbak, the STW weight rider, the baggy unaerodynamic clothes to claim that a small reduction in overall weight makes a difference to you going at the speed of light through singletrack.
I think the main issue is that it's partially unsprung weight if it's on the bike, whilst if it's part of the rider (and you're riding competently) that extra mass is travelling with a flatter smooth trajectory.
Anyone will two bottle cages on their bike and a Camelbak could experiment with this by carrying water either on the bike or on their back, and then attacking some singletrack and seeing how it feels. However, if you're not riding actively then your weight will be less well sprung and you might not notice the difference.
Al- I used the words sciencefact, did you not see?
...and describing the effect in terms of 'massive' or 'huge' or 'the size of an elephant'....
Yes. It depends on what you mean by huge. See my above post.
Do I think it'll make you 15 minutes quicker up the Afan climb? Of course I bloody don't.
...and convieniently ignoring the huge camelbak, the STW weight rider
The fact that you think I'm SO stupid to have actually overlooked the relative weights of rider and bike doesn't reflect well on your own powers of thought and ability to follow an argument on intelligent terms.
The most simplistic angle is to calculate 5lbs as a percentage of total bike+rider weight. I'm saying that there's a lot more to the physical model than that, but perhaps more importantly the human interpretations of the consequences of the variables in that model are quite subtle.
ONE example being that if you finish a 5hr enduro 5 mins before someone else, that's a sizeable victory, but a pretty small percentage of time.
Have a read and a think, you might learn something from all the valid posts on this thread that don't insult the posters.
And yes I know I am being insulting and antagonistic, but I'm annoyed.
AH OK Luke so you are ****ing about.
The most simplistic angle is to calculate 5lbs as a percentage of total bike+rider weight. I'm saying that there's a lot more to the physical model than that,
...which makes even less real difference than the 5lb. And 5m in a 5 hour race, 1.8%, I wouldn't call it a significant victory at all.
Sorry mate, it's guff.
...which makes even less real difference than the 5lb. And 5m in a 5 hour race, 1.8%, I wouldn't call it a significant victory at all.
I would. Plus that was only one example of the many aspects of the issue.
Sorry mate, it's guff.
No it's not.
Yes it is.
No it's not.
Don't know if anyones said this already as I couldn't be arsed to read through all the science and pseudo science but how much the rider weighs must make a difference - bigger heavier rider it'll make less of a diference. 7 stone rider it'll make a huge difference, 14 stone rider much less of a difference.
110% guff!
Peak power of the rider makes a difference too. If you can put more torque into the pedals at any given instant, you're more likely to be able to get a 35lb bike moving in two or three pedal strokes after a hairpin.
Jeez do you fannies seriously worry about getting your sled back up to speed after you've minced round a hairpin?
Where's GW when you need him?
Jeez do you fannies seriously worry about getting your sled back up to speed after you've minced round a hairpin?
I don't worry about it, no. I just like to think about these things.
Why do you want GW here? You didn't listen to him before.
GW is the king of acerbic wit against trail centre mincers.
no he isn't 😀
If I'm murdered, it was Professor Molgrips, in the Sports Science lab, with the poorly calibrated scales.....
I R not trail centre mincer.
Reviving this thread unless it`s 5lb difference on an identical bike so many other factors...in last 6 months have ridden Syfyrrdin Taril at Nant yr Arian on 3 different bikes noting times:
June on Ti Van Nic (25-26 lbish) 2hr 37 min
September on Giant Trance FS (30 lbish) 2hr 43 min; legburner climb 16.5 min
October on Cotic BFe (30 lbish) 2 hr 30 min, legburner climb 15.7 min
As I weigh , with Camelbak kit etc, 190 lb my conclusion from above is that it`s more about the bike overall than bike weight per se. Of all above Cotic by far the most fun to ride and most lively feeling 🙂
so many other factors
Indeed...your power output on each of those rides was identical?
Dont measure actual power output, BUT felt I was trying same amount on each ride so thats as scientific for me as it gets, point taken though but for me I`m not worried about the extra 5lb in the case described