First off: this is not a argument about how Gravity works.

I was looking at the Evil Sov threads and reading some reviews (see bikeradar) and recall seeing one discounted in Keswick. The shop owner wanted me to hold it but I know the power of touch and refused!

Anyway, I have a Mongoose Tyax frame in the garage – 2.8kg of solid aluminium made it ride like a tank which seemed a bit much for my tender riding style – hence I now ride a Boardman HT most of the time.

But with big tyres it was brutishly solid downhill (only let down by the fork I had really). So I was looking again at Dialled Alpines, BFes and the gloriously expensive Sovereign and wondering if, in fact, it’s the sheer low mass of these bikes that makes them thunder through all obstacles instead of skipping and dancing around like the lighter bike I ride now?

Yes, once they get the momentum built up they go faster for longer due to their weight…They are also more stable in the air…

In forum land maybe…

And if it was the case, would Steve Peats’ mechanic really gone to this much trouble?

http://www.bikemagic.com/gear-news/steve-peats-santa-cruz-v10/7279.html

No!
but there is a point where too light a bike is detrimental to DH performance and too heavy a bike will tire the rider (different weights for every rider)
if you can handle both heavy and ight DH bikes, tyre choice can often make more difference.

having the skill to handle the lighter bike would make all the difference i’d imagine…lets put it this way i’ve a feeling 99% if not all of the top professional dher’s would choose the lighter biker if all else was equal.

Your “feeling” doesn’t stack up! check out the weight of Gee’s WC winning bike. he could have had it built up a good bit lighter if needed fairly easily!

What makes the bike/rider combo bounce going over terrain? An inability to absorb the terrain.
Therefore one or more of the suspension components (tires/fork and or shock/rider) will be responsible for the bouncing.
Mass has very little (though some) to do with it.

I reckon if you just set off, no pedalling and no braking, then a heavy bike might well win but once you’re accelerating & decelerating, lightness helps (assuming stiff & durable enough)

Engineering is compromise.

If a designer had the option, there would be parts with strength of Ti with zero mass and friction could be removed completely. For all other situations there is engineering and therefore compromise.

Just need to know where you can make it whether its Strength for weight or grip for speed.

http://video.mpora.com/watch/NPBiVu3SW/

Results that day:

1./ Greg Minnaar 3.23.42

2./ Gee Atherton 3.23.67

Poor Gee – Stevie must’ve forgotten to tip that water out the BB, eh? 😉

Vinney, WTF are you on about?

http://video.mpora.com/watch/NPBiVu3SW/

pretty much all just under 40lbs

session 88 was lighter than the carbon v10 too!

Your “feeling” doesn’t stack up! check out the weight of Gee’s WC winning bike. he could have had it built up a good bit lighter if needed fairly easily!

purely guessing, never rode a DH bike in my life.

No shit? 🙄

pure shit apparently! 😆

Tandems go quicker DH then normal solo road bikes.

But off road, there’s a limit.

*goes off to make a zip line over a trail to run bikes down riderless, all in the name of science (not ramber crushing)*

GW – Member

“Your “feeling” doesn’t stack up! check out the weight of Gee’s WC winning bike. he could have had it built up a good bit lighter if needed fairly easily!”

Aye but he did say “if all else were equal”- would you say Gee’s bike was built up purely to add weight or was the weight a side effect of going for durability and reliability? Doesn’t seem like it’s the former.

Put it different, if he could have had the exact same performance from the bike other than making it a couple of pounds lighter, no sacrifices, do you reckon he would have?

Back when I knew Dan and Gee to speak to (from racing against them a long time ago) Dan would, Gee wouldn’t.. no **** idea now, why don’t you ask him?

Not sure he’s a member here tbh

I meant in real life

We don’t drink in the same local… Did bump into him at the nationals last year but sadly the topic didn’t come up.

But you’re our Stig, just was interested to hear your opinion.

My mate used to go on about how super his pimpy hubs were and how fast they rolled and nobody could roll faster etc etc until I turned up on my £100 wheel set and, without us pedaling, pulled away quite nicely down a fire road.

He was furious so we swapped bikes and again, I pulled away, with no pedal effort. It must be the difference in riders then and as I am a bit heavier, probably 3 stone, we concluded it must be a momentum thing.

it follows that heavier bikes must also have the same effect. Basically, bumps, stones lumps etc have less of an effect upon their progress.

Surely a pro DHer would go for the lighter bike for the improved acceleration and braking that having lighter weight entails.

ok, being sensible for a second; rolling down a smooth hill then a heavier bike would be better. riding a dh track where you rarely travel at the speed you could potentially reach because you are setting up for the next corner, jump etc., quickly accelerate and decellerate, flick from one line to the next etc. then a bit lighter would no doubt help

it follows that heavier bikes must also have the same effect. Basically, bumps, stones lumps etc have less of an effect upon their progress.

only if you simply sit there and plow an un-planned path down the hill with all the finesse of a cow 😉 but you’re kinda right.. I roll way faster than all my lighter mates too but I’m not a faster rider than all of them and my bike is slightly lighter (the faster rolling comes from a combination of higher tyre pressures and higher durometer rear tyres, suspension set-up and me weighing more)

SbZ – with respect you probably have little to no comprehension of how much/often a top pro DHer actually touches their brakes, where you’d be white knuckling your brake levers they’d be pumping the terrain for more speed, carving a precise line that requires less slowing down in the first place or pedalling.

Hmm. Insults aside please. And I’m not really interested in the DH racing angle.

Momentum seems so important to MTB – that ability roll over things rather than be stopped by them. I weigh loads more than my bike so I don’t see why an extra kilo on the frame and wheels makes a difference.

But feels like it does.

insults? 😕

sorry but IMO gaining and carrying momentum is far more important in DH racing than any other mtb discipline/genre and the same principles of gravity translate into all the other types of off road riding, maintaining/gaining momentum doesn’t however come from simply sticking a bloater on an heavy bike and letting them steer it badly down a hill or a poor rider changing the weight of their bike by a few pounds either way.

GW, everyone has to brake at some point and a lighter bike would allow them to leave that braking later and they can sure do with a lighter bike to sprint on through pedaly sections.

Vinney, WTF are you on about?

Basically a combination of what coolhandluke, sbz and buzz-lightyear have said.

only if you simply sit there and plow an un-planned path down the hill with all the finesse of a cow but you’re kinda right.. I roll way faster than all my lighter mates too but I’m not a faster rider than all of them and my bike is slightly lighter (the faster rolling comes from a combination of higher tyre pressures and higher durometer rear tyres, suspension set-up and me weighing more)

I’d have thought the assumption was that both bikes took the same path down the hill, else what’s the point of asking the question.
By the way, it’s a common error to make, but higher tire pressures are slower rolling off road as a rule, unlike on the road.

As I said earlier, the fastest bike down the hill, all other things being equal will be the one that makes the best job of smoothing the trail out, not losing momentum or being deflected by obstacles. Mass/weight will have very little to do with rate of progress.

Don’t make the mistake of equating the weight of suitable equipment with it’s performance.

SbZ – it makes no difference how late you brake if your super lightweight bike is kicked off line or falls apart before you even reach the braking point 😉

By the way, higher tire pressures are slower rolling off road as a rule, unlike on the road[b] WRONG![/b].

from this I’m assuming you’ve simply read this somewhere and not bothered to fully understand it rather than actually doing your own experimentation with different tyres and pressures for your own bike where you ride?
By the way… I said higher pressures than my (lighter weight) mates’

Most places we ride mountain bikes are rough and we are constantly changing direction, cornering, adjusting our speed etc

A lighter bike will brake better, corner better and will allow for better damping..so in the real world, overall, a lighter bike is better.

However, I’ve personally found very light wheels to be unnerving and lacking in stability/tracking for DH. So your back to compromise. Doesnt seem to be a problem for Steve Peat mind.

Steve Peat doesn’t ride “very light wheels” DH or low tyre pressures for that matter.

“only if you simply sit there and plow an un-planned path down the hill with all the finesse of a cow”

You’ve been spying on me?

GW – you don’t come across very well on here. It’s the language you use, name dropping, implication that no else can ride etc. How old are you?

All else being equal, a heavier bike lowers the CofG. But Looking at that vid of Gee vs the guy on the motorbike down fort william, the lack of mass makes changing direction so much easier.

GW – Member

Steve Peat doesn’t ride “very light wheels” DH or low tyre pressures for that matter.

He clearly does sometimes, but his go in the bin after one run and he would probably sacrifice all out speed over any feeling of stability. Having said that if you look at what most pros run, many of them run wheels very to me, or in some cases heavier – obviously through choice.

Tyre pressure is obviously gonna be subjective, it’s clear to see many racers run low pressures.

“He clearly does sometimes, but his go in the bin after one run and he would probably sacrifice all out speed over any feeling of stability.”

Depends what you mean by “very light” doesn’t it, he’s not up there on Roval Controles… Very light for DH is probably true. The Enve rims they’re using now are stupidly light but not weak so it’s not a tradeoff of weight vs strength, it’s a trade off of weight and strength vs enormous cost, that most people wouldn’t do. Supposedly they’re more durable than the alu rims too.

PS, GW’s a bit difficult to listen to sometimes, he’s a bit spiky but still- you should be listening.

There’s some truth in the ‘lower pressures roll faster’ thing, but only up to a point. 35psi probably is faster than 50, but 25psi is slooowwww. I don’t believe that the top racers can be running the low pressures that some people talk about, their cornering speed must dictate a minimum pressure higher than a trail riding mortal surely? Anyway I’ve strayed off the point, the weight thing – if you’re strong then I can’t see more weight is much of a penalty downhill, yes the bike is more effort to move around, but, all things being equal you benefit from a stiffer, stronger bike.

tis an interesting point. Heavier bikes feel more stable and planted, lighter bikes accerate quicker. The DH i’d personally choose a medium weight bike.

you don’t come across very well on here.

oh… really? 🙄

It’s the language you use,

English? What? too articulate for you? sorry but I’m not going to “dumb down” just so those with poor comprehesion can feel better! ;(

name dropping,

Any regular UK DH racer will have brushed shoulders with Pro DH riders week in week out, there’s a hell of a lot of standing around, sitting in cattle trucks, discussing the track, bike set-up etc. and they are just normal approachable people like you and me who enjoy riding bikes .. Northwind asked my opinion so I gave it.

implication that no else can ride etc.

other than your own insecurities, where exactly do you get that from? I have already stated I’m now a slower DH rider than mates.

How old are you?

Sorry mate I’m already taken 😉 😛