Viewing 40 posts - 1 through 40 (of 79 total)
  • 5 lb weight difference – how significant?
  • bonesetter
    Free Member

    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

    cynic-al
    Free Member

    1. “feels slow” =/= slow.
    2. FS will usually “feel” slower.
    3. FS may not make sense for your riding.

    wwaswas
    Full Member

    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…

    steve_b77
    Free Member

    Rule 5!

    robholland
    Free Member

    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

    karnali
    Free Member

    stick 5lb in a rucksac and acarry it around for a few hours see what it feels like

    bonesetter
    Free Member

    Yes, the descents were a little 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 🙂

    agentdagnamit
    Free Member

    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.

    robholland
    Free Member

    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.

    druidh
    Free Member

    My FS is lighter than my hardtail…..

    molgrips
    Free Member

    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.

    balfa
    Free Member

    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!

    cynic-al
    Free Member

    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.

    molgrips
    Free Member

    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.

    nickc
    Full Member

    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?

    cynic-al
    Free Member

    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?

    hora
    Free Member

    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.

    tamworthcrowd
    Free Member

    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.

    TheSwede
    Free Member

    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 ?

    molgrips
    Free Member

    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.

    cynic-al
    Free Member

    The tighter the singletrack, the more times you have to brake and accelerate of course.

    Do folk really ride like this? Sounds very tiring.

    molgrips
    Free Member

    It is, but that’s not really a bad thing. It’s also brilliant fun 🙂

    bonesetter
    Free Member

    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…

    nickc
    Full Member

    Aye, it’s a lot isn’t it? doesn’t sound like it though.

    nonk
    Free Member

    its loads, i am in the molgrips camp.

    cbrsyd
    Free Member

    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.

    Munqe-chick
    Free Member

    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

    cynic-al
    Free Member

    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.

    molgrips
    Free Member

    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 🙂

    vinnyeh
    Full Member

    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 some 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.

    GW
    Free Member

    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.

    molgrips
    Free Member

    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

    😯

    GW
    Free Member

    vinnyeh – 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.

    GW
    Free Member

    But so what if it just feels faster? We never time our recreational rides, so surely feeling faster is enough?

    Maybe you don’t! 😛

    molgrips
    Free Member

    Alright most of us don’t 🙂

    cynic-al
    Free Member

    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.

    GW
    Free Member

    TROLL-BATTLING-EPIC-LEGEND.

    What happened on that thread in the end Al?

    vinnyeh
    Full Member

    @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.

    GW
    Free Member

    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.

    molgrips
    Free Member

    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…?

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