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I went out for the first time in a couple of months on my 13Kg (~29lb) FS and was struck by how slow if felt on the climbs and on the flat (even on the descents it felt like a burly trail bike).
My HT weighs in at around 5lb's less, so is it a case of
a) I need to just MTFU as I've lost 'FS Fitness' and a feel of what the bike rides like, 5lb doesn't make all that much of a difference
b) My HT is is superior handling bike
c) 5lb really does make all the difference
1. "feels slow" =/= slow.
2. FS will usually "feel" slower.
3. FS may not make sense for your riding.
5lb does make a difference.
If you enjoy the trails on a hardtail maybe FS is 'too much' for you.
I rode my FS bike about 5 times this year but my hardtails went out twice a week. My FS bike weighs less than the hardtails too...
Rule 5!
My hardtail is always quicker uphill as its lighter, but then i love the control and comfort of a full sus on rough stuff. So i wouldn't mind 5lbs for a nice full sus bike. MTFU option
stick 5lb in a rucksac and acarry it around for a few hours see what it feels like
Yes, the descents were a [i]little[/i] faster, but the HT can be skipped and floated more, overall the FS did not have the sprightly feel to it
I'm drifting into FS/HT differences, but the pedaling effort needed was very noticeable. This the biggest thing
What I can say is the HT was much more enjoyable.
Crikey! I'll be on a 29er SS rigid and growing a beard at this rate 🙂
5lb - less than the difference between a full camelbak bladder and an empty one, normal weight fluctuation on a long ride if you're carrying all your water.
A grey beard. I suppose it depends on what kind of full sus as well. I tried a Scott Spark other day. Felt like a hardtail but with a nice bouncy edge.
My FS is lighter than my hardtail.....
The dweebs on here will try and tell you that 5lbs is a small fraction of the total weight so will make little difference when winching up a steady fire-road climb, which is true.
However on singletrack, where the bike is being accelerated up, down, forwards, backwards and side to side many times a minute or even second by you, your brakes or your tyres, 5lbs makes a massive difference.
But of course there are FS and FS. Lighter FS usually have steeper angles which makes for a better pedalling position and a load of other handling factors. It depends on the trails too and the style of corners etc. My Orange 5 (28lbs) is much much faster around Swinley singletrack than my Kona Heihei (21lbs), because the geometry works much better for those trails.
On the other hand, my Patriot was 31lbs new and pretty slow. I made the tyres tubeless which saved maybe 0.5lbs and it's now much faster and more lively, because the rolling resistance is now significantly lower.
When I bought my first FS I tested one of the first FSR 120s and a Fisher Cake. The FSR was maybe 2lbs heavier, but felt an utter dog on the climbs, whereas the Cake climbed like a spanked goat. They had very different angles.
I recently lost this amount of weight from my hardtail and I'd say it does make a noticeable difference to how it rides. It makes it much more playful and can be thrown around much easier. However, I can say I've noticed much difference on the hills. I was slow before and I'm slow now!
However on singletrack, where the bike is being accelerated up, down, forwards, backwards and side to side many times a minute or even second by you, your brakes or your tyres, 5lbs makes a massive difference.
Psychologically, it does make a difference. Speed will vary little though.
Regards
Dweeb.
If there is a lot of braking and accelerating, then speed will be significantly quicker. I worked it out on paper but I can't remember the numbers now. I think it was something like 2lbs off the bike and wheels made you faster up hills as if you had 5W more power; on a typical stretch of twisty singletrack it was like having 40W extra power.
But despite that, the debate about what's faster is totally academic, since it's all about feel rather than ultimate speed, isn't it. And light bikes are definitely more manoeuvrable, and accelerate and brake quicker. Which makes it more fun. As long as the bike is strong enoguh, IMO the only time heavier bikes are better is when you are steaming down a boulder field.
FS always feels slower, you're not being banged about like on a HT, but it could be draggy tyres, or lower pressure, or that you're just used to the HT. Don't sweat about it, who wants two bikes that feel the same anyway?
I think it was something like 2lbs off the bike and wheels made you faster up hills as if you had 5W more power; on a typical stretch of twisty singletrack it was like having 40W extra power.
So you assume it takes 2.5W per lb to climb?
What assumptions did you make for the second calc?
Too much sag/etc on the rear? 5lb is sod all. I bet its the rear shock sagging/sapping forward motion or grippier tyres etc.
Well where is that extra weight, is it mostly static or rotating mass (i.e. wheels)? Static won't matter as much as rotating mass obviously. If they're compatible, swap the wheels from your HT to your FS and see if that feels faster. If yes, get lighter tyres, innertubes, rims for the fullsus.
Let's not forget nige's fs is a 29er and he is 11 feet tall. Drag co efficiences must come in to the equation ?
5lb is sod all
It bloody well isn't. If you don't think you'd notice 5lbs of lead strapped to your frame and wheels, then you're a seriously slow pootler!
Cynic - I can't remember how it went now, but I assumed accelerating from slow to fast a certain number of times per minute as you might expect on tight singletrack. The tighter the singletrack, the more times you have to brake and accelerate of course.
I also assumed that you were pinning it, since if you are just trundling about it makes no difference.
The tighter the singletrack, the more times you have to brake and accelerate of course.
Do folk really ride like this? Sounds very tiring.
It is, but that's not really a bad thing. It's also brilliant fun 🙂
After seeing the weight difference of the two bikes, I decided to see what 5lbs actually looked like, so I went to the kitchen scales and it took 2 big full muesli bags to make it up. Or 2 1/3 standard size bags of sugar...
Aye, it's a lot isn't it? doesn't sound like it though.
its loads, i am in the molgrips camp.
Where the weight difference is is important. If the HT has much lighter wheels that the FS it will definitely climb easier and accelerate quicker.
bike weight is more signficant than rider/kit weight; its "unsprung weight" with the riders arms and legs as the springs. Picture a flowing rolling bit of singletrack with the bike being pumped "into" the track and the sprung mass, the rider's torso, following a straight line.
http://en.wikipedia.org/wiki/Unsprung_mass
I think it's reasonably well established that rotating weight makes a bike feel a lot faster but in the real world doesn't make a huge difference at all, and not much more than static weight.
Picture a flowing rolling bit of singletrack with the bike being pumped "into" the track and the sprung mass, the rider's torso, following a straight line.
Picture a fat middle aged man plonked in the saddle trundling along nice and slowly... 😉
Al - it makes a HUGE difference to me.. but we are just different riders it seems 🙂
I worked it out on paper but I can't remember the numbers now.
Come on molgrips, give us a taster. You must be able to remember [i]some[/i] of it.
FWIW though I agree with most of what you said- racy frame angles are generally found on light builds/ cruisier angles on more robust builds- and I think that's why a lot of people expect light weight to equal a faster bike, when in fact it's that the design males it a more efficient pedalling machine.
from owning 2 very similar hardtails (except one is 26lb and one 31lb) and three similar DH bikes (@ 37lb, 41lb & 46lb) alongside each other and often riding more than one bike in the same day I can assure you 5lb does make a pretty huge difference in handling, stability and manouverablility. wheel weight makes big difference to acceleration and climbing but also a huge difference for stability over rough ground and in the air.
I've had DH bikes ranging from 37lb to 52lb and hadrtails from 22lb to 35lb over the years and although a lighter bike will usually climb smooth climbs or accelerate out a gate faster weight isn't always a bad thing but it obviously depends where the weight is too.
Light weight is definitely a factor though. Of course it's not going to make you into Andy Schleck (obviously) but those extra lbs add up if you are hammering singletrack as fast as you can and you will end up more fatigued more quickly. And if you are racing, it's important for your lap times of course.
But so what if it just feels faster? We never time our recreational rides, so surely feeling faster is enough?
52lb
😯
vinnyeh - Memberracy frame angles are generally found on light builds/ cruisier angles on more robust builds- and [b]I think that's why a lot of people expect light weight to equal a faster bike, when in fact it's that the design males it a more efficient pedalling machine[/b].
Think you're wrong! Take 2 identical 4X hardtails. use the exact same same light weight (4.5lb) Alu frame, build one with XO/Reba/ProII/717 and light dependable finishing kit the other with old Saint/Argyle/721 and average DH worthy kit and you'd have one 25lb bike and one 30lb one. both as efficient pedalling as each other but with the same rider on board the light one would make up a bike length out a start gate, change direction faster and be more manouverable. take them both on a proper DH track and although less manouverable the heavier one will be easier to control.
But so what if it just feels faster? [b]We never time our recreational rides[/b], so surely feeling faster is enough?
Maybe you don't! 😛
Alright most of us don't 🙂
FWIW though I agree with most of what you said- racy frame angles are generally found on light builds/ cruisier angles on more robust builds- and I think that's why a lot of people expect light weight to equal a faster bike, when in fact it's that the design males it a more efficient pedalling machine.
I still disagree - angles can make a bike feel faster, but make it physically more efficient? I don't think so.
Al - it makes a HUGE difference to me.. but we are just different riders it seems
In real terms i.e. time? And who says I ride? I'm just a forum-troll-bot come armchair-engineer come TROLL-BATTLING-EPIC-LEGEND.
TROLL-BATTLING-EPIC-LEGEND.
What happened on that thread in the end Al?
@GW, I didn't phrase that very well, did I. Of course you're right, and 5 pounds will make a big difference, especially on wheelset changes, though I've never been able to lose that much weight off a bike.
What I'm trying to say is that people often focus on the weight difference between two frames as the source of the difference, rather than the geometry.
I could lose 5lb off every bike I own fairly easily but I wouldn't want to ride it afterwards, durability is as important to me as weight on a bike build.
I still disagree - angles can make a bike feel faster, but make it physically more efficient? I don't think so.
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.
In real terms i.e. time?
Dunno, but it sounds like you don't go flat out on singletrack as a matter of course...?
I still disagree - angles can make a bike feel faster, but make it physically more efficient? I don't think so.
more efficient to pedal was what I meant.
5lbs = 1/100 Singlespeedstu 🙂
wish my 08 wolfridge weighed 5 lbs less. 🙁
GW - Membervinnyeh - Member
racy frame angles are generally found on light builds/ cruisier angles on more robust builds- and I think that's why a lot of people expect light weight to equal a faster bike, when in fact it's that the design males it a more efficient pedalling machine.
Think you're wrong! Take 2 identical 4X hardtails. use the exact same same light weight (4.5lb) Alu frame, build one with XO/Reba/ProII/717 and light dependable finishing kit the other with old Saint/Argyle/721 and average DH worthy kit and you'd have one 25lb bike and one 30lb one. both as efficient pedalling as each other but with the same rider on board the light one would make up a bike length out a start gate, change direction faster and be more manouverable. take them both on a proper DH track and although less manouverable the heavier one will be easier to control.
How about take 2 different frames of the same weight, one racy and one slack and put the same kit on each, would they feel the same? No.
The answer is weight and geo both make a difference, why do all these threads just turn into black or white disagreements when the world is grey 🙄
Because its full of internet heros who know theirs is the one true path?
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