Global Mountain Bike Network hi guys Do you guys have an email we can contact you on about testing and review our latex and ammonia free tire sealant and our very own flat base valves with a built in valve core remover
I'd love to see a more realistic video; using two identical enduro frames, on one leave stock components and on the other put a lightweight carbon wheelset, carbon bars, lightweight saddle, lightweight groupset etc.. and compare times and rideability
Agreed....that was not real world at all. No one is going to put water in their wheels. I would have rather seen a heavy AL wheel, and heavier casing tires...like DH casings. Weird idea to test.....
It's not always going to be wheels that are heavier though is it? This is just to show disadvantages of additional weight, not how heavy are your wheels?
mopedvieh ... I guess I would have liked to see how weight added to the wheels, increasing the rolling weight, would have interested me more, but you’re probably right if the goal was just to add unsprung weight without adding rolling weight.
You added weight to the wheels, increasing the unsprung weight, but that also increases rotational mass doesnt it? I'd be interested to see that portion again repeated but with the weight on the chainstay and fork lowers instead.
Putting unsprung weight in the wheels is also adding weight to the rotational mass, thus making it even worse than if that weight was added to the fork and rear end. So it's not a very valid unsprung weight test. We have known for a long time that adding a pound or two to your frame isn't a huge deal, but adding a pound or two to the outer part of the wheel (Tire or Rim) makes a HUGE difference. So if you want a faster bike, the first and best place to lose weight is in the tire and/or rim. Going tubeless is the cheapest way to take off rotational weight and it's a better ride anyway. Lighter tires and lighter rims would be next. Lighter spoke nipples and spokes after that. A lighter hub doesn't help much, but a lighter cassette helps some. All those places will make a bike, even with a heavier frame and other parts, a lot faster.
Especially the added weight which is in the form of water that sloshes around in the tires. The results of added unsprung weight portion of this test is not useful and realistic at all
It seemed to me that the presenter really didn't understand the difference between unsprung and rotational mass. To your point, using a liquid to add mass, made matters worse because liquid mass is unstable (i.e. moving independently of the rest of the wheel). In order for this test to mean anything, having 4 groups would be most effective. A control group (basic bike with no added weight and relatively light wheel/tires - as done), test group 1 (added sprung mass - as done), test group 2 (added unsprung mass at the suspension - e.g. on the swing arm and fork lowers) and finally test group 3 (added mass in the wheels by running heavier wheels/tires/rotors). Also, knowing how to make the most out of your braking distances would help.
Next go watch Marc's and Neil's "How to brake like a pro". How would the weight affect braking if you would actually move your body weight where it should be?
Good subject and varied areas to test but please try to minimize the effect of the rider by doing each 3-5 times and removing the outlier. And the idea of testing the difference between sprung and unsprung mass was thrown out the window the moment you went +75% mass compared to the sprung setup.. Also talking about "the amount of water sloshing around" seems you found this out in practice. Have bike 2 and 3 had the same weight the video could have provided consumers a good idea when comparing similar bikes (in price and components etc) but with good light tyres and heavier frame vs the opposite setup. Now, in the end, it almost just states the obvious
By putting water into the wheels, you added unsprung mass AND rotational mass. Therefore, you canged two parameters in one test series, making it impossible to evaluate. The weight should have been added to the lower legs of the fork or the chain stays
Would have been better to use solid weights on the rims than water. First of all you don't get inconsistent feel due to the fluid weight, and you're not reducing the inner volume of the tire, causing totally different tire behaviour. But nice nevertheless. Welcome to the community.
I noticed the difference between bikes when I was demoing some for my last Enduro bike. My conclusion was that you didn't want to go too light on the frame but have the lightest wheelset you could get away with without risking breakages or punctures. Hence why I bought a Cotic Rocket (steel frame) above the carbon options. It just felt the most planted out of all the bikes I tried, stable in the air and on the ground and the suspension just got on with doing what it should. It may be a bit slower up the hills but all I've done to offset that is run a slightly wider range cassette compared to my other bikes, 32/11-46T opposed to 32/11-42T. There's only 2kgs difference between it and my trial bike (only just under 1kg is in the frame!) despite the different builds, the same as a full Camelback vs an empty one so really not worth worrying about. I just choose which bike to take depending on where I'm riding and what I am prioritising that day, fun on the downs or a mixture of fun and distance. More important for me is to lose the extra 10kgs I put on last year!
So in summary I should buy light carbon wheels, but not bother getting a carbon bar, strap some tools and spares on it and have a water bottle, and I'll be winning right? :)
A) You added rotating un-sprung weight. B) You added a lot of unpredictability by adding water. Who knows what it is doing. C) Weight balance probably had more to do with your stopping results than actual weight. Good test for what running too much sealant feels like, bad for everything else. Should have added the un-sprung weight to the frame in a place it would have been un-sprung and maintained the weight balance of the stock bike.. . Bad test
I thought that was you on Wednesday when you were filming. Annoyed I didnt say anything now! Sweet video though guys :) (anyone wondering where this is, its rowberrow (somerset). come down and ride you will love it )
Why did you not do a test with Cushcore its extra 0.5 kg for unsprung weight and results would be completely different to that tires filled with too much water
The downhill water test needs to be redone with genuine weight, adding water in tyres completely changes the handling characteristics so outside the control test parameters.
Water in the wheels. Brilliant idea. 1958, Len Beadell and his team drank water stored their tyres to stave off dehydration and complete the Gun Barrel Highway. Up there you might want to Fill them up with warm soup.
The test would be a lot more interesting by just comparing a normal bike with DH tires and alloy wheels to one with lighter tires and carbon rims. Also it would be interesting to hear more about the "feel" of the bike. For example a lighter bike (especially wheels and unsprung weight) would potentially feel more playful, more fun in the air, nimble in the corners etc. while a slightly heavier bike might feel more planted and good through the rough stuff and going straight.
Adding water to the wheels just increases rotational weight AND makes them less stable. Also, with less compressible air in the tire the tire will feel will be more progressive, which also make them less compliant and lowers traction. This is not a trade off. It is just something that makes things worse. Instead, you should have put bigger tires with less pressure.
Mr Porter would have been an invaluable addition to this presentation. That being said I await the onset of punters queuing up at CRC for expensive weights to add to their bike...
Brilliant test and well presented! I was wondering if you could do a similar back to back test with the typical stuff you carry on a 20-40km Sunday ride. For example you could load up a camelback with 3L of water. Spare tube, food, emergency tools etc. then mount some of these items on the frame to compare. You could also compare a bumbag to a camelback and a just a water bottle and accessories on the frame.
U guys couldn't have been that daft. Adding loose rotational weight instead of static "unsprung" weight was a dumb comparison. I really hope this was intentional to trigger us. I don't want to know either way.
When adding sprung mass, you NEED to change the suspension settings to ensure a fair test. You say it rides better with the extra sprung mass, but how can you qualify that when the preload/sag ratios are different? You need to either add mass and adjust preload to match the control bikes sag, or adjust the control bikes preload to match the sag of the bike with the added weight. If you're starting off at a different point in the suspension stroke and the suspension has a progressive, rather than linear response, you could be introducing a huge change right away, never mind the effect of reduced travel!
Good stuff! One additional bit of info. would be adding the sprung weight to the bike vs. adding it to the rider. How does adding a few kilos to the bike compare to adding that same weight to the rider? This would be interesting for those of us who may want to reduce the weight of our bikes, but we could also stand to lose some weight from our mid sections! :) For example, is it worth it for someone who's overweight to invest in reducing the sprung weight of their bike? Could be a fun experiment for a future episode!
The water in the wheels didn't just increase the overall mass it also increased the angular momentum which would account for the added difficulty in handling.
That water in tires: Try roll ball filed with water. It has so many efects that unsprung weight is nothing compared to rotation mass efect and water friction.
I'm really not sure what to do with this information? Ultimately what is the outcome? GMBN are running out of content ideas? Next video: selotape a parrot to the top tube and glue a fruit pastille to the bar ends.
Fundamentally, the bike weight question comes down to this: Should I drop $1k extra on carbon wheels, $1k extra on carbon frame, or $1k on beer? To this end, I have a few thoughts: Pros: -Aiming for 1.5 kg difference in weight I think is a good region because this is roughly the difference between a NX aluminum build and a XO1 carbon build. I think that this would definitely provide some valuable and interesting consumer insight. -You did the test at all. Cons: -Because the added weight differs between the sprung vs unsprung weight, it makes it unclear whether the additional weight or the sprung/unsprung-ness of the weight is the issue. -Doing more runs on this would really make a huge difference... it could be a bit of work, but if you did these tests Mon-Friday for 3 weeks, you could probably get some more meaningful statics...or if you got 2 friends and all did this for 1 week and compared even. Please do this!!!!!!
consider testing, a setup, heaver versus light, trackstands, tricky riding where quick adjustments are needed to maintain control, slow or fast speed on singletrack.
Small increases in unsprung mass have the effect of reducing acceleration but create more of a spinning top effect. 1 gram of rim weight to balance my front 20” tire and rim yielded an extra minute of free rotation in a standardised static test.
You can't use water in the tyres. That's not taking into consideration the geater gyroscopic effect of heavier wheels because the water will always sit at the bottom of the tyre, it won't spin round, which is the whole point in lighter/heavier wheels.
Maybe we could see a comparasion between wheelsets, for example one very heavy rim, running dh casing tires, tubes and suxh, vs a carbon or lightweight alu wheel, tubeless, and a lighter casing tire
Explains why ebikes are so stable going downhill and on the air. For normal bikes, unless you don´t mind the extra wheight or you do uplifts it could be beneficial, however, I wouldn´t add more than 2 kilos because it becomes harder to balance and predict under gnarly terrain. Great video to give us a rough Idea. Also keep in mind that water is almost uncompressable, so under hard hits it can make the tire explode or feel like landing with no suspension.
To properly assess the effects of the additional rotational weight it is best to fit a heavier tire as that actually rotates vs the water that more sloshes and sits to the bottom of the tire
My old school full susser is 11kg and has been taking a pounding for 2 decades. Agile, easy to lift over fences, easy climber, quick going down as well
The locations of the weights on the increased sprung mass bike would have made a difference to how the bike handled. You're not going to add a kg to your cockpit, it's likely the frame that's going to be that kind of increase. The water sloshing around inside the tyres would also have affected the handling, would have been better to try a very heavy wheelset instead. This is the sort of thing that people are interested in but nobody seems to do it particularly seriously. Doddy did it between a trail bike and an e-bike, which is another wildly exaggerated comparison and not representative of the choice people might want to make in real life (e.g. trail vs enduro bike).
It would have been a better test, i think, if you added solid weight to say the hubs, instead of water in the tires. 1kg of lead attached to each of the hubs for example would add 2kg and would have minimal impact on the rotational weight.
Think about trying to spin a half full water bottle in the air.... The resistance of the water stops the rotation almost straight away, if you have ever towed a half full water tank behind a car you would be familiar with the free-flow effect on handling. Can you please do this again with fixed weights on the wheels instead of sloshing water. Even just sliding the weights you put on the frame between the spokes would have been a more accurate option.
Water in the tires is nothing like the rotational weight of heavier wheel components; much of it will remain in the bottom of the tire instead of rotating with the wheel.
Of course the obvious flaw in this test is that you not only increased unsprung weight but also rotational mass. For pure unsprung weight increase you should have simply added weights to the fork legs and chainstays. AS was said for decades by weight weenies: 10g reduction in rotational mass equals 30g reduction in total, non-rotating mass.
This test is kinda like comparing 29" wheels to 26" wheels. The 29" wheels having more rotational mass and harder to get moving and worse on trails, while 26" wheels less mass and faster on trails. I think the bike industry sold the riders a bill of goods when they came up with 29" wheels and how much better they are. Then with bigger wheels you have to have wider handlebars for more leverage to turn the heavier wheels. After riding a 29er, jump on a 26" CC bike with 700mm bars and it feels like you are flying. Don't get me started on 1x drive train...
I also think changing the shock settings would be totally beneficial to each bike too.... the change of spring rate on the downhill section, the times would have defintely been different
The weight in your wheels is rotational mass, and water moves around when riding, also the mass higher up the bike wil make your balance worse than your low balance
Imo, weight does matter, when you ride in a straight line, going downhill may actually be better on a bit heavier bike, because more weight will increase speed, for better or for worse :D Also the breaking momentum will be less, more mass, more force needed to stop, so more time to stop. Bigger tires roll better downhill not just because of rolling resistance, but also because of weight Bike needs to be sturdy, as we know, or most of us, just because it weighs the same, does not mean it's as good as identical weight bike. Frame matters, consistency of welds, and stuff like that. Some frames creak, some stay silent. It's part of that question too. How light? How sturdy? Walmart carbon bike? or Specialized carbon framed bike? Very big differences there.
I love having a light bike and it's a 20yr old full suspension. I was riding a full suspension before they became cool to ride. It has a listed weight of 26.5lbs
Well that proves very little. It has been long held known that the best place to save weight is on the wheels. This is because the wheels have to be accelerated in a straight line and rotationally. As for sprung mass the best place to lose weight is from the rider - well it is in my case ;-)
Interesting idea for the test, although I'm guessing water in the wheel is probably more of a part of the rotational mass (unless water level would stay even somehow), which isn't quite the same as adding weight on fork legs, etc... Should partner with GCN folks for some of this :D
I'd like to see your take on building a super lightweight trail hardtail. The selection of carbon frames for such a build is relatively small and dishing out 1600 for a yeti frame - even with life time warranty - seems a bit steep without knowing how much the outcome is going to be worth it. I've ridden an aluminium trail hardtail before but I wonder weather it makes that much of a difference to go from +14kg to maybe 10 and lower. Old faithfull cost me 1500 to build, a sub 10kg build will certainly come in at more than 4000.
I weight 105kg ( 231lbs ) ride a fat bike weighting 20kg ( 44lbs) just the bike with no absorbers, and I carry in it a emergency toolbox, some 10 to 20kg (again 22 - 44 lbs) of stuff, so according to this, I should carrying a total mass of 130kg ( 286 lbs ) over only "tire bounce absorption", and should not be able to make sharp turns on high speeds than a full suspension thin bike and a light rider. However, a big part of that weight is my legs, my core, and my blood, which accounts for what many parts of car do. And that makes all the difference in the same situation to someone who weights 40kg less than me, with overall the same bodyfat index. I love anecdotal evidence based science.
Water to the wheels is pointless as its adding little rotational inertia or momentum as the water is free to move independently of the wheel apart from the relatively small hydraulic shear resistance. It also affects the compressional volume of the tyres thus affecting the smoothness of the tyre effect.
When looking for new bike I got quite surprised that double suspension Merida from 2009 was 12kg,but not even the most expensive Merida are lower then 14kg. Why is that?
There is no control over rider variability in these tests. Is the effort expended on the climbs identical? Is the effort and line identical on all of the descents? I don’t think it is possible to control these rider inputs but they certainly impact the results.
With all that water inside the tyres, theres going to be less volume for the air to occupy so its got to affect the handling and the ride characteristics a bit don't you think?? But as it's for a weight to weight comparison, not a bad way to do it!
What if you added the weight to the front and rear forks instead of the tires? I feel like the increased rotational mass is the issue for the unsprung weight, not the weight itself.
I have always wanted to know performance and handling differences between Standard bike v Bike with water bottles ,v bike with Camelbak, and bike with fanny pack with water . As higher centre of gravity and lower centre of gravity could make a huge difference on handling!
Surely you know you could have done this better. One go on each braking test? That was the operator not the weights. Not changing suspension settings? That would have made stock and sprung feel the same. Adding more weight to the wheels than the frame made weight the difference, not it’s location. I have an indoor trainer wheel that I have 950g of water in the tube for more mass. But I have minimal to zero air in that tube. You should have pumped up the wheels with minimal to zero air so it behaves better. And then you should have tested weight at the bb and stem separate. There is no realistic condition your handlebars stem and components would weigh an extra kg more than the lightest set up you can buy.
I like my #Pinion gearbox! Takes the weight off of the rear suspension thus making it awesomely! Putting at the crank makes the bike much more stable. Ya maybe slightly slower on climbs, but see if the average rider can catch me on an average trail ;)
Good content. It happens to me I'm a much better downhiller when I am off season 63 kgs than when I am fit around 57. The heaviest stabilize my bike a lot 😉
@@JohnBooth Im sorry I've missread your first comment, don't mind my bollocks. You are right the lower the unsprung mass, the better the handling and the quicker are the suspension reactions.
Still don't understand this current trend. When people blast out thousands of dollars on the most expensive and lightest carbon frames, just so they can strap all kinds of crap on the frame, put it inside the frame with SWAT or even put crap in your steer tube and then top it off with couple of water bottles... Does not really make sense to me.
Would of been a better test if he used lighter wheels as that's always what people suggest and show that difference as water in the wheels will always throw you off due to sloshing round
