[Closed] Does lighter = Faster ? All other things being equal

I weigh 90Kg+ kit. So from 99Kg to 101kg = 2%.

Aka nowt!

the lighter bike will accelerate slightly quicker but once upto speed the differences are probably non existent (assuming there are no hills)

Don't think you can quantify it in time. Its down to the amount of effort needed to propel that weight around for 1 hour. The rider on the lighter bike will expend less energy for the same ride at the same pace.

Is this road or MTB?

I think weight is key for road as its more based on power to weigh ratios.

Ascending and XC on the MTB is very similiar to road so I would say weight would impact it. Descending I think weight helps, I think Chris Porter formerly of Mojo was doing testing recently where he was adding weight to bikes as it made them more stable at speed and helped maintain this speed.

The discussion is for MTB.

Specificially from my POV it's for MTB racing... So fatigue only plays a factor in the context of the rider being able to go harder at the end, not a question of how tired the rider is once they've finished.

The reason i'm asking of course is because i'm curious as to whether i should spend some money and buy an XC whippet bike for racing XC... Or just stick with my Parkwood/Whyte T130

You ride Zwift Weeksy??... w/kg aint it. Those 2 kilos will be added to your overall weight and need to be pushed up the hills. So slower up, possibly faster down, and negligible difference on the flats if all else is equal. But more energy overall will be used to move bike b than bike a.

On a heavier bike, particularly with heavier wheels, it's only really noticeable when powering out of corners on twisty turny courses.  You need to put a bit more effort into the pedal strokes to accelerate the way you are expecting to, and you might need one more pedal stroke.  Over time, this adds to your fatigue.  So whilst the maths may say no when it comes to working against gravity, I think it does matter in your overall race times on a windy course.  Which most XC courses seem to be.

Same weight tyres having different rolling resistance? Trade off with grip etc, but all out speed might be affected

You ride Zwift Weeksy??… w/kg aint it. Those 2 kilos will be added to your overall weight and need to be pushed up the hills. So slower up, possibly faster down, and negligible difference on the flats if all else is equal. But more energy overall will be used to move bike b than bike a.

Different weight though isn't it ? not just the overall weight of rider and bike as it's sprung/unsprung, etc

In a Zwift context, 2kg doesn't make much difference at all.... but i don't think that 2kg Zwift weight is the same as 2kg bike weight.

I think weight is key for road as its more based on power to weigh ratios.

in the mountains it's true, on the flat it's all aero riding bikes 1 kilo over the limit.

How technically adept are you? Are you going to loose the time you've made up climbing when descending on a flighty steep angled xc race bike? I am increasingly begining to think that i need to make some weight conscessions to aid my inability to descend - in particular I think adding 300g to get a dropper post is probably worthhwile.

How technically adept are you? Are you going to loose the time you’ve made up climbing when descending on a flighty steep angled xc race bike? I am increasingly begining to think that i need to make some weight conscessions to aid my inability to descend – in particular I think adding 300g to get a dropper post is probably worthhwile.

I think the simplest answer to that is.... "i'm average"... This is where in particular the argument of any purchase falls down for me. If i race at Southern XC i would say expect to finish 30th out of 55....  (2017 results roughly). Lets say i was on a bike that was even 2 minutes quicker over the time/course... that may only push me up to 28th place. Or indeed a slower bike of 2 minutes may again, be 2 places down to 32nd...

My "should i buy..." all falls apart right about there... but doesn't mean i'm not tempted.

In general, lighter will be faster, but that needs to be qualified a lot. "All other things being equal" is nonsense, they won't be equal, some things will be different. The speed difference will depend a lot on the trail and the rider. On long, steady climbs, a 2 kg difference won't make an enormous difference. On twisty XC pedaling sections, a lighter bike will probably accelerate better, but that will depend on the fitness of the rider. If it's a very short race, acceleration out of corners might make a difference, but if it's a long race, you will mostly be spinning along trying not to blow your heart rate up so a heavier bike with better handling might carry more speed out of the corners. A professional XC racer might be able to benefit from a superlight bike, but an average rider might not. If the descents are rough, bigger, grippier tyres will help, especially for average riders, on smoother descents, skinny lightweight tyres might be the way to go.

On top of that, slimming 2 kg off a bike's weight costs serious money. That's money you could use for something else, so you need to identify the most cost-effective way to go faster.

All things equal - then yes. But in the real world for us weekend warrior xc types, then I doubt it makes much difference as there are many other factors that impact on our race before a tiny amount of weight makes a difference.

Anyway, I have just done the swap from carbon (cracked it) to the old alu frame I had lying about. I reckon I will still be racing the same folk for 20-something place come the southern xcs.

Ferrals - yes, get a dropper. Mine has added 400g, (brand x external one) but it makes enough of a difference on a technical descent to make it worthwhile. Just feels safer too, so you don't worry about drops and other tech features. My local trails seem to be getting a trail-pixie make-over too (yay!) so tech features are becoming more common on every ride now.

Have you included uphill and downhill differences? The heavier bike will roll faster downhill than the lighter bike. Likewise a heavier rider will too.

So another question: 2 riders of the same fitness and same bike tie in a race. One rider is 60kg and the other is 90kg. Now give them both a bike thats 2kg heavier on a course with a mixture of gradients. Who will win?

If you want a lighter bike, buy a lighter bike.

If you want to get faster at XC, from your current mid-pack, training and skills coaching will be a better investment.

I got a load faster on twisty wooded XC after some skills coaching with Jedi - I was able to carry more speed and corner much faster.

The reason i’m asking of course is because i’m curious as to whether i should spend some money and buy an XC whippet bike for racing XC

Spend what you want to spend, what are your goals? Fun or Podium? If it's fun spend the cash on going to the races and some kit, if you want to go chasing the g and podium then find someone to sponsor you 😉

Does anyone really think that buying a new bike will make more difference than being really fit?  Daftest advice ever.

Who will win?

Depends on their power to weight ratios of course.

Spend what you want to spend, what are your goals? Fun or Podium? If it’s fun spend the cash on going to the races and some kit

My wants and my realistic goals are a million miles apart. i WANT to be a podium, but the simple fact is that whilst i've dropped 8kg off myself this year i'm still 10kg if not 20kg away from being a podium kind of guy. Sure, a heavy guy may podium, but he's also a lot fitter/faster than me...

It's all about the fun.... but i'm a bloke, so part of the fun comes from the battles.... If a lighter faster bike puts me in more battles for higher places, then that has the side-effect of being more fun.

Here's one thing I will say, a lighter bike 'feels' faster, there is some science behind it whereby the body senses changes in acceleration more than changes in speed so a faster acelerating bike is going to 'feel' faster. So having a lighter bike means having more fun!

weeksy - do it. Sounds like you want the carbon xc bike anyway. Scratch that itch. I thought the same a while back and bought a 2nd hand dirty harry frame from here (you've seen it - the bright pink one). Loved the way it rode. It felt fast, if maybe only a tiny bit faster. A bit gutted when it cracked, but it's had a decent run being 6 years or so old.

It'll cost you a bunch of cash if you carry it through to its logical end. A while back, I built my Maverick ML7 to a point where it weighed around 21lb with pedals etc, which was light for what it was. It felt super lively accelerating out of corners etc and quicker on climbs. Definite psychological boost.

But... I would have been better off spending the same cash on a coach and personalised training plan and living with a bike that weighed two or three lb more.

You need to weigh and cost everything - all the small savings add up - and see how much it'll cost you, then ask yourself whether proper coaching - and maybe some weight loss - won't give you much more bang for your buck.

As a compromise, super light race wheels and tyres will make the bike feel faster, but mine got to a point where I was breaking things on any sort of normal trail ride, so it became pretty much a dedicated race bike.

I have given up worrying about weight on my XC bike. I do mainly road racing and downhill but last year I did 4 xc races. I came 3rd, 8th, 3rd and 2nd. I noticed a few things that made me change my bike to make it faster in certain circumstances.

Firstly I noticed how completely useless a lot of xc riders are at descending, even at the sharp end of a race. I probably made up most of my places overtaking on the downhills. For this reason i put bigger tyres on and a dropper. I was happy to sacrifice a bit of uphill/flat speed for the downhill speed.

I also beefed the wheels up. I used to use stans crest rims but they constantly felt like they were going to collapse. Talk about flexy. I changed them for some mavic 819's which give the tyres a good round profile which i like for cornering.

I swapped back to flat pedals. Again its amazing how may riders cant get clipped back in after dabbing for a corner or a traffic bottleneck. Coming from road and dh where you don't unclip much I include myself in this and the rush and heat of the moment of a race doesn't help. I passed quite a few people on steep uphills by being able to get back on the pedals sooner.

So for me weight isn't at the top of my list. i need a bike that's good on the downhills and will suffer a bit of drag on the ups as a trade off.

One of the guys I ride with weighs 18st - ex rugby player- but trounces all of us fairly fit blokes on the ups. He has no interest in making his bike lighter, he just buys what's in the shop. I try and keep my bike as light as I can afford but never seem to get anywhere near him. You can't beat genes especially fit genes!

weeksy – do it. Sounds like you want the carbon xc bike anyway.

What i WANT is a Stanton... LOL. But i don't think that the Stanton will give me anything that the Parkwood doesn't give me already. Whether i wend for the Slackline and used my Hope pro4's or whether i went for a Sherpa and used the 29er bits, i don't think it would give me anything MORE in the context of XC racing/riding anyway.  I do think it may give me a bit of WOW that the Parkwood doesn't give...

However the Parkwood is an absolutely EXCELLENT machine at what it does and the budget it's at.

Interestingly i'm planning on using this weekeneds Swinley meetup to jump on both my T-130 and the Parkwood and see which one i ride quicker on over a generic XC route, i was thinking Seagull, or Stickler, whichever the flat twisty one is.... That's the trail at Swinley that most mirrors Checkendon XC course i think, so was going to do back to back riding of it and see which of my 2 bikes i'm quicker on.

The T-130 is more flickable, better handling and dual suspension, lighter wheels. The Parkwood has the 29er wheels, is a bit slower in the turns but rolls superbly... The answer to that question may open up all sort of other thoughts i may or may not consider.

I totally get that making myself faster/fitter/lighter is the way forward, believe me, i get that. That's why i'm Zwifting so much, hitting the diet and trying to drop from 98kg down into the 80's bracket, which i'm not far from now. But realistically, 88-89kg is about as low as i can really expect, i'm never going to be a 70kg lightweight bloke... the time, training, diet and comittment is WAY above me to ever reach there.

Where are you most likely to pass other riders weeksy ?

I've never ridden an xc race but guessing that singletrack sections are likely processions and all the overtaking happens elsewhere.

If you could smash a downhill, slightly off the preferred line on your heavier bike, might you pass more riders than you could by overhauling them on a gradual hill ?

Alternatively, are the overtaking opportunities in places where you might need to burst round somebody on a flat or upward bit, where a light bike might just make a difference ?

last year I did 4 xc races. I came 3rd, 8th, 3rd and 2nd.

What cat / level / series & how many entered? As they're impressive results

I probably made up most of my places overtaking on the downhills.

I overtake loads of people on descents, and also flat singletrack.  However I lose it all again on the climbs, so I wouldn't personally bother with improving my bike for the descents - I manage fine.  But improving it for climbing would help.  More time is gained or lost on climbs I think than descents generally.

Over the years I've come to the conclusion that making yourself lighter has more effect than making your bike lighter on how fast you are

Where are you most likely to pass other riders weeksy ?

At the Southern XC courses i'd say the passing opportunities are more likely to be on the ups than the downs, or at the least, the flat bits.  Certainly at Checkendon for sure. The main passing places there are 3 field sections, which are fairly flat (the start finish is slihglty downhill, but a wide fieldy taped off route), so really the 'infield' section in the majority is singletrack and non-passing unless you're using brute force.

That kind of suits me really as i've got a certain amount of Watts at my disposal which could in theory mean i burst the watts on them bits and then recover in the singletrack.

However, what has happend in the past is that i'm so destroyed and breathing like i'm about to expire in the singletrack, that when i get to the flat fieldy bits i'm already trying to recover 🙂

sounds like you need to get a turbo trainer - they're pretty good, I've heard

<<span style="display: inline !important; float: none; background-color: transparent; color: #222222; font-family: 'Open Sans'; font-size: 16px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; line-height: 22.4px; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;">Over the years I’ve come to the conclusion that making yourself lighter has more effect than making your bike lighter on how fast you are</span>>

plus 1 your W/kg is the key and less weight makes you faster in all areas and more agile

I think we can safely say i'm OK there... 🙂

This is where Zwifting has plusses and minuses as it's hard to replicate an XC race when sitting in the garage. The closest i can think of is the shorter races i like doing because you can end up at your limit, then needing to kick on to hold the bunch etc... In the longer races it's often a slog on Zwift and i'm not sure how real world them sort of rides are to me. But i honestly believe that if i can''t ride in the woods, then what i am doing is hopefully the best type of effort i can do for what i want next month.

Training at Swinley/etc of course is FAR better... but very rarely do i get the chance to do so.

plus 1 your W/kg is the key and less weight makes you faster in all areas and more agile

Of course, but you can buy a bike in 24 hours that's 2kg lighter than your current bike... .Dropping weight is a LOT harder and a much slower process.

As i've stated, i've dropped almost 10kg in 2018, so it's not like i'm not already doing my best on that side of things..

This is where Zwifting has plusses and minuses as it’s hard to replicate an XC race when sitting in the garage.

Try something like sufferfest or trainer road for some much higher intensity workouts and intervals,

Try something like sufferfest or trainer road for some much higher intensity workouts and intervals,

Last Zwift race i did was at an average of 170bpm, with my absolute max of 182.... i'm not convinced anything outisde of a pack of rabid dogs could make me work harder 🙂

Intervals, yes, i'll give you that... But i'm not a trainer road kind of guy.

It's more about the variety and structure than just going hard for some time, if you get the sufferfest humour then it's good at motivating you

last year I did 4 xc races. I came 3rd, 8th, 3rd and 2nd.

What cat / level / series & how many entered? As they’re impressive results

sorry i did 5 not 4.

2 x elite. the 8th and an 11th

3 x enthusiast ( or whatever its called) 3rd 3rd and 2nd

It'll be a bit faster, everything else being equal.

It won't be slower down hill, as long as you're used to it.

Pedalling up a steep fire road, as others have said, about 2%. Some benefit on the flat with less rolling resistance due the the lower overall mass, but the wind resistance will be the same. Some benefit on the downs from being able to accelerate faster and chuck the bike about easier (but on a terminal velocity descent you'll be a bit slower as your drag will be the same but forwards force from your weight lower - this will be more than made up for by the climbs).

FWIW I considered the benefit of a dropper post, and decided it's worthwhile on an XC bike to descend faster, despite the ~300g weight penalty.

Essentially it's not going to take you from a mid field finisher to a podium regular, but it could make the difference between 1st and 2nd, or 21st and 22nd, depending on where you usually finish.

Plus it's nice to know you've done everything you can to go faster and it's just down to putting maximum effort climbing/maximum commitment descending on the day.

Edit- I run a Parkwood, but it's more of an all-rounder, as I don't do enough races to justify an XC race bike. TBH I could save 3lb by swapping the frame and forks, but it would cost me lots of money to the point that I might as well just but another bike...

Dropper, TBH i rarely use my dropper even at the best of times. I have a Magura Vyron i can swap in seconds from bike to bike (assuming a 30.9 fits of course) but even at places like Afan i rarely use it. Checkendon, i can't see any reason i'd use a dropper though.

Depends on their power to weight ratios of course.

Exactly. The point is 2kg of extra weight on a bike will have more of a negative effect on a riders overall W/KG who is 60kg than a rider who is 90kg. 2kg of extra weight to a heavier rider will be less noticeable (less % gain) than 2kg of extra weight on a lighter rider.

Another example. My cars 0-60 is the same as a friends car. Mine has a much smaller engine and lower power output but still the same 0-60. Add 3 passengers to both cars and mine cant keep up anymore.

Intervals, yes, i’ll give you that… But i’m not a trainer road kind of guy.

The point of intervals is that they make you faster than just randomly blatting around at full gas in a race scenario, by doing super threshold intervals ou actually spend more time super-threshold as you allow your boody to recover inbetween, just going full gass you will be compromised and not hitting those max watts as regularly.

FWIW one of my favourite xc training things to do is to find a climb that goes straight into a singletrack descent, do hill reps but rather than stopping at the top, do the rep then straight into trying to ride the singletrack as fast as possible for a few hundred yards before recovering. Much harder to ride singletrack with sweat blurred vision!

Dropper, TBH i rarely use my dropper even at the best of times. I have a Magura Vyron i can swap in seconds from bike to bike (assuming a 30.9 fits of course) but even at places like Afan i rarely use it. Checkendon, i can’t see any reason i’d use a dropper though

Everyones different, and I've never even tried a dropper, don't even have a qr seatpost - but I believe there are many a/b splits that I'ce gone B on where if I had a dropper I'd have gone A, so that means I'm either putting in another little sprint to get back to people (adding to fatigue) or being dropped if riding tight to someone in front. I reckon i might jsut have a paly with a seat lowered 10cm and see if I'm faster/more confident on the descents - woudl be good stanidng pedling training too!!

Dropper, TBH i rarely use my dropper even at the best of times. I have a Magura Vyron i can swap in seconds from bike to bike (assuming a 30.9 fits of course) but even at places like Afan i rarely use it. Checkendon, i can’t see any reason i’d use a dropper though.

Yeah it depends where and how you ride.

When I did the sums, I needed to save such a small amount of time on the descents that it was worth it for me - but I do like the saddle down even when I don't *need* the saddle down, just to be able to chuck the bike around.

Also, I broke my wrist in an accident I probably would have avoided with a dropper.

Way I see it, if I'm going to be putting the effort in to train to be as fit as possible I may as well have the right tool for the job to get the most out of all that grafting on race day.

Not all weight is equal however.. Light wheels and tyres make far more of a difference than a light frame

Simple answer is yes.  How much is irrelevant.

The difference felt or seen on a 500g lighter bike may be negligible but differences nonetheless.

If you were comparing a 10kg bike against a 100kg bike I think the answer would be a bit moire obvious, but 10kg and 11kg is still a difference.

Simple answer is yes.  How much is irrelevant.

The difference felt or seen on a 500g lighter bike may be negligible but differences nonetheless.

If you were comparing a 10kg bike against a 100kg bike I think the answer would be a bit moire obvious, but 10kg and 11kg is still a difference.

If it's a bike you know, the differece can be huge. Going from winter tyres to faster lighter summer tyres (probably about 500g difference, which you feel when just jumping on the bike, as well as the faster rolling which is a different matter altogether!) makes a big difference to the feel of my bike...

Edit - meant the difference can feel huge. 500g is not going to actually make a huge difference to your actual speed.

I also do a bit of XC racing on a heavy-ish trail bike.

Yeah I'd be quicker on a XC race bike but I'm not serious enough for one and at least it gives me a ready-made excuse for only being 4th in that "enthusiast" race mentioned above.

😉

Yeah I’d be quicker on a XC race bike but I’m not serious enough for one and at least it gives me a ready-made excuse for only being 4th in that “enthusiast” race mentioned above.

I take it we're talking more fun here, as top 10 in Elite is bloody impressive

top 10 in Elite is bloody impressive

Althogh depending on what series 8th elite might well be second last [big smily laughing emoji to make it unequivocal I'm teasing the poster]

Bloody impressive getting to the level you get to race in elite though!

On a circular ride, you'll get the potential energy back, so it's really just kinetic energy. For me 2 kg extra means about 2.5%, so that's the difference in mass, For the SAME power, that means a difference in velocity of sqrt(1.025) - 1 or about 1.25%, you will struggle to notice this compared with extraneous factors such as temperature, air density, wind, tiredness, etc... So the real world answer is none.

I can actually do this experiment on the road, as I have a Giant Defy Advanced SL and a Giant Defy 5 all alloy (including forks). The difference in weight is about 2 kg, but I already know that the alloy Defy handles pretty much the same as the much more expensive Defy, I haven't done any timed routes to test yet.

So basically we're left with

"Buy a bike if you want one.... but it won't make you any quicker you fat ^$^%^& "

🙂

Have a look at the Vitus Rapide Weeksy and tell me what size you are.   I'm thinking of selling mine and using the Scott Spark.

That mainly depends on this weekends race.  Its very non technical so the Spark is overkill but I need familiarity for my target marathon races.  Can I race on one bike thats 2lbs heavier?  Probably.

On a circular ride, you’ll get the potential energy back

Only if you don't brake. And even if you didn't brake, going up you are losing more than you can gain going down as wind resistance increases the power requirement for a given speed as a cube of the speed.

And even if this wasn't the case, you spend more time going up, so you wouldn't make the time back even if your downhill speed increased by the same proportion that your uphill speed decreased.

I take it we’re talking more fun here, as top 10 in Elite is bloody impressive

The Midweek Madness series in NW England only has two adult male cats, "racer" and "enthusiast". The former is all lycra, the latter is a mix of lycra & baggies.

So basically we’re left with

“Buy a bike if you want one…. but it won’t make you any quicker you fat ^$^%^& ”

A proper XC race bike would be quicker for sure. People just enjoy being contrary on the internet.

People must race different XC events to me, I find the opportunities to pass on downhills / singletrack very very limited and for the most part too risky to try.  I used to use descents mostly to close gaps (if I had space) or recover and then absolutely smash any fireroad sections or dual track.  Best I did was I think 6th in BBD one year and a 10th overall in one of the Gorrick BM series.

I went from an old anthem x1 to a pimped scale with power meter / carbon rims etc... it didn't make much of a difference.  The biggest difference to my performance was buying a road bike.

If you can handle a super light flighty bike they are really quick, round trail centres I am only slightly slower descending on the scale than I am on a nomad, but something like twice as fast ascending.

People must race different XC events to me

+1

Most of the elite events i've done over the years, the guys at the pointy end are seriously quick downhill.

Unless there isn't any point in going fast, as you'll only gain 3 seconds, but tire yourself out for the next climb/flat (and lose 20).

There is a difference between a downhill racers speed and an xc racers dh speed. If you are used to dh racing with good size rock gardens and decent size jumps then ill argue that xc downhills are pretty easy. I have passed many people by taking the risky line but in a dh race it wouldn't even be considered an obstacle.  I found that even whilst passing people going down hill i was still able to get enough rest to recover for the next hill/effort.

Weeksy, for Checkendon- NO. IMO. What you will gain in the slight acceleration advantage you’ll lose in handling. It’s so rooty that you don’t need a light bike- you need a planted one. And it’s pan flat!!

What will gain you time is training. Skills sessioning  and intervals. It’s that simple.

Make up a course around your cul-de-sac going up and down the curbs and round parked cars and time yourself. Then try and get faster. It doesn’t need to be Swinley or BPW.

Your power curve is also too flat. It’s almost the exact opposite of the power demands of Checkendon. Work on it! Ten or thirty second sprints with big recoveries. Beast yourself up the Watopia hilly KOM (2min), recover and do it again.

Or use the workout mode and smash your way through one of the HIIT sessions.

Sitting at Threshold in a Zwift race won’t build you a top-end.

Relating it to my season last year- at my one XC and one CX  race, I lost out in the corners as simple as that. I had to slow much more than the others and accelerate much harder and whilst I could maintain that for a lap or two- my lack of efficiency ground me down much sooner. People spend time doing skills sessioning and clinics because it’s a huge part of off road racing .

Many of the guys you’ll be racing against will be racing all the time too.

I think a Southern XC podium is a huge goal (ie one that will take a couple of seasons)- looking at the results, the top of the Open category always feels a bit ‘sandbaggy’ 😱🤣

I think a Southern XC podium is a huge goal

I'm hoping that was for you ? As I honestly think it's completely unrealistic for me 😀

In 2017 i was 9mins+ behind the winner and 7mins behind 10th....  It equated to 2 mins 15 per lap... I just don't see how that's going to be a realistic goal for me personally.

If i'm honest I finished 2mins 20 behind Yak of this here forum. He's my target 🙂 Whether i can get closer this year, i don't know.... but i'll have a damn good try 🙂

I plan on setting/planning 2019 much better from a dates perspective and making it to far more Southern XC events. This season, i can't do round 2.... but i'm thinking 1/3/4 i should be able to wangle with the wife/footy stuff and get to them.

Have you done Southern XC before ??

The only reason I ask is I reckon from the Zwift stuff we're pretty similar, same weight power out stuff.

There was a younger faster version of me that I'm trying to get back to, the younger faster version of me could do a full lap of Swinley in 1hr:10m (i can't get near that at moment) however in the Open Cat at Southern XC the best he ever managed was 18th

Some serious riders seem to enter the Open (they should be in Sport at least)

Bike won't matter too much.

I built an XC race bike, not because I needed a lighter bike but because I wanted one set up for the purpose.  Short travel, skinny tyres, racy position and steep angles.  My Patriot isn't an awful lot heavier, maybe 3-4lbs (the XC bike is heavy), but the riding position makes me want to just sit and spin in a relaxed way, whereas the XC bike makes me want to put the hammers down.  Might be psychological, might not.

Bike won’t matter too much.

Did the odd round on my bikepacking bike, fully rigid with bags still attached.

It's childish but because I know I can't win sometimes being the guy with baggies and the wrong bike is more fun. (especially if you overtake the odd lycra clad S-Works Epic)

[img] [/img]

The Midweek Madness series in NW England only has two adult male cats, “racer” and “enthusiast”. The former is all lycra, the latter is a mix of lycra & baggies.

This is true, and I've done a few 🙂

Basically, back to the bike thing, if you want a bike go buy it and stop trying to justify it with minute gains

Tiger.

http://my5.raceresult.com/66810/results?lang=en#3_77C4BF

33rd. ive done more Gorricks than Souterns though

20-25th is my aim

You see you look at that in context the Top10 in the Open Cat beat the hour for the course, all 10 of those would have been competitive in the Sport Cat.

I built an XC race bike, not because I needed a lighter bike but because I wanted one set up for the purpose.  Short travel, skinny tyres, racy position and steep angles.  My Patriot isn’t an awful lot heavier, maybe 3-4lbs (the XC bike is heavy), but the riding position makes me want to just sit and spin in a relaxed way, whereas the XC bike makes me want to put the hammers down.  Might be psychological, might not.

This is all true, but I've been trying not to talk about "other things" (including the rider) as the OP asked whether losing weight would allow him to go faster.

It would.

A bit.

How much depends on a lot of factors.

And re. people getting stuck behind folk on the singletrack, well that could happen wherever you are in the field, but it can happen uphill too. It's definitely personal preference for droppers.

I don’t know why but I’ve always favoured heavier bikes. Bfe, Trans AM and currently looking at a Big Wig. Not a great rider and always find the weight reassuring when I fling myself down or over stuff. I’ve had lighter bikes and they just feel fragile even though I know they aren’t.

As a few people have alluded to - phsychologically it could speed you up.

If you aren't collapsing at the finish line like Sam Gaze did this past weekend, then your body has more to give. There are many ways to get some of this out of yourself, but making equipment choices that you believe are faster can make you faster, whether that be the scales reading, the presence or absence of a dropper, or (so I hear) the feeling of air over fresh shaved legs.

And if you aren't good enough to be at your true limit (I include most people in that), that psychological benefit could outweigh the physical penalty

Well I did write you a long answer to this question but this stupid site crashed and lost my text so you'll have to settle with. No, it'll make no difference.

That's a shame. Still thinking about a light fast 29er FS, but the problem comes that a decent one and light enough would set me back about £4000. I don't really feel the £4000 would be justified considering my lack of ability along with already having a damn decent bike too.

I really could do with weighing my t-130 though to see what it comes in at in XC trim.

It's extra complicated because so much of it is software. I love the feeling of a light bike, and it makes me put more in- if the first pedalstroke feels productive then my next one is stronger, if every lift feels easier then I flow the terrain better. It's not because the light bike makes it possible- I could do the same on a heavier bike, but I probably won't.

Taking out 3 brake rotor bolts each end and stripping off paint didn't make Steve Peat's world champs bike faster... But possibly knowing his bike was as light and as ready as it could possibly be, helped him be faster. Special tyres Cole!

The total mass of rider; bike; cycling kit; emergency repair kit; water etc. will have a big influence on climbs of ~7% or greater. The steeper and longer the climbs are, the greater the benefit of the whole package being lighter.

You could test this yourself on Zwift, on the new Alpe Du Zwift, playing with the weight figure.

I noticed yesterday on that Zwift hill that even at 222W average for my climb from the second hairpin and then a full descent, the Calorie expenditure was huge, ~1100 Calories for 74mins25secs. I've put on ~2Kg since Xmas, now ~78Kg, this climb will be a good way for me to lose those excess snacks while trying to at least maintain (ideally improve) my sustained power output.

Why not get set off light wheels and tyres for racing. Rotational weight more important overall acceration etc etc if u can knock 500grams or more it will be noticable.

I have light rubber one Hope pro4s. Admittedly they're the 3SW rims, so a long way from light, but I can't go back in time and change that decision now, so the wheels I have are staying.

You could test this yourself on Zwift, on the new Alpe Du Zwift, playing with the weight figure

The issue with that is that a large majority of the course is fairly flat. So it's not going to tell us much for the race.

Well that was interesting (to me anyway) I bought a cheap Chinese luggage scale thing from Ebay. Not for the actual weights of my bikes, but for the comparative weights compared to eachother.

The conclusion is, my Parkwood is 1.45kg less than my Whyte T-130 in full XC tyres (both bikes have Maxxis Crossmark II's as their XC rubber, both tubeless)

I can only assume the forks i thought were very light on the Parkwood actually ARE very light...and the shock/frame on the T-130 are quite heavy. I know the wheels on the T-130 are not like being the super wide Hope 3SW's, but i doubt the standard Parkwood Rattlesnakes are particularly light either.

But 1.5kg is a decent chunk of weight off the bike.... Hmmm food for thought.

Whipped out the wheels and did some more weighing

The rear wheel on the Whyte is 300gr heavier than the Parkwood, but the front is 200Gr lighter. Same seat on both. Cassette on the Parkwood is 35gr lighter. Pedals are 3gr difference in favour of the Whyte (Nukeproof).
Seatpost on the Whyte will be heavier as it's a bit longer and fairly cheap too.

Both running exactly same cranksets and BBs. so it seems the majority of the weight is in the forks/frame rather than anything else. X Fusion Sweep RL2 are on the Whyte which seem to be around 1900gr and the Fox  forks from Germany everyone bought i believe are 1550gr... So there's 400gr of it...