Why weight nonetheless issues on a mountain bike… however not for the explanations we have all been instructed

Are heavier bikes more durable, slower and extra tiring to experience? Time to change an e-bike in a quest to search out out

A lighter bike rides higher than a heavy one, proper? It’s an thought most of us have agreed with through the years as a result of, merely put, we all know it to be true. Our personal expertise has proven us {that a} lighter bike climbs extra simply, all different issues being equal. Lighter bikes deal with higher, soar additional and are usually extra enjoyable.

After which one thing occurred that blew that considering proper out of the water. We received e-bikes. Out of the blue the greatest electrical mountain bikes being produced weighed greater than 20kg, half as a lot once more as a equally specced common bike with the identical journey. 

Early days: the 2016 KTM Macina Lycan pushed out 250W, weighed a scant 21kg however the geometry and experience really feel had been appalling

And sure, a few of them rode like a sack of spuds, significantly the early ones just like the Big Full E+ 1 from 2016, and there have been loads of errors and rising pains: However right now’s e-bikes are a few of the greatest using bikes we’ve ever examined, and that features analogue bikes too.

So what on earth is happening? If weight issues a lot, why don’t e-bikes completely suck once you’re going downhill? (You may even suppose they do, however that’s a distinct story.) 

My principle is that it’s as a lot about the place weight sits on a motorbike and the way the suspension and geometry is constructed round it, as the load itself. In an effort to search out out, I’ve run a crafty again to again take a look at to search out out whether or not including or subtracting weight to a motorbike actually does make a distinction to the experience really feel.

Canyon Torque Mullet AL 6

You and the bike work as one when loading the bike right into a nook… however much less so when issues get unfastened and the bike strikes beneath you

Fable busting

Earlier than we get there although there are a couple of myths that have to be sorted out as soon as and for all. We’ve heard it mentioned {that a} bike’s weight is essentially irrelevant as a result of we have now to take the bike and rider weight collectively as a system. Begin with an 80kg rider and it doesn’t make a lot distinction to the general weight whether or not you add a 15kg bike or a 20kg bike, the idea goes.

I’d argue that’s true in some conditions, and never in others. The precept works properly in some corners, you employ your weight to drive grip by means of the tyres and by and huge you and the bike are working as a single unit. 

That concept begins to go flawed once you come out of the nook although, hammer over a tough part of path or get on something unfastened, slippery or off-camber. The perfect abilities teaching, and certainly your personal using information tells you to get unfastened and be able to let the bike slide beneath you. Clearly this can be a disconnect, and a motorbike’s weight issues massively when this occurs. 

How to bunny hop a mountain bike

It’s simpler to bunnyhop a light-weight bike than a heavy bike, a ability all of us do tons of of occasions every experience

Likewise, bunnyhopping a mountain bike requires you to tug the factor up into the air. It’s easy physics, on flat terrain if you would like the bike airborne you need to soar first and pull it up after you. Sure you possibly can load the tyres and suspension considerably, however crucial issue is you dragging the factor skywards. If that wasn’t the case then BMXers with rock arduous tyres and no suspension would discover it not possible to bunnyhop.

To chop an extended story quick, a heavy bike is extra weight to pull up into the air, a lighter bike is much less weight. Which do you reckon will acquire extra top? We carry out little bunnyhops on a regular basis as we experience our bikes, and a light-weight bike undoubtedly makes this simpler.

Canyon Torque:ON CF9

The Canyon Torque:ON is a monster on the descents, and the right take a look at mule because of its interchangeable battery sizes

Heavyweight champions 

Heavy bikes do quite a lot of issues higher although. The suspension efficiency is superior as a result of the ratio of sprung to unsprung mass is healthier. We’ve in all probability all heard this one million occasions, the unsprung mass is the wheels, fork lowers, the air can a part of your shock that strikes with the swingarm, and any related fittings. The sprung mass is all the remaining. Enhance the sprung weight and preserve the unsprung weight roughly the identical (as on an e-bike) and your bike turns into a extra steady platform for the suspension, letting the wheels keep higher contact with the path and due to this fact generate extra grip. 

With 650ml of water and an additional 150Wh of battery, it’s easy to extend the Torque:ON’s weight by round 1,500g

Again to our weight take a look at: the bikes

Clearly we’d like two bikes for this take a look at, with precisely the identical spec however totally different weights. In fact that’s not possible, two equivalent bikes will even have barely totally different weights because of vagaries of tyre weight, body and elements, and that’s earlier than we even begin speaking concerning the distractions of misplaced effectivity or suspension efficiency. 

So to take away all these variables we’ve gone with a single bike, the Canyon Torque:ON. This works as a result of you possibly can take away as a lot as 1.5kg of weight from the identical bike just by swapping battery dimension and eradicating the top-tube mounted water bottle. So no janky bolted on weight, and a take a look at bike fully devoid of variables apart from the load itself… and naturally me, the take a look at rider.

Canyon Torque:ON CF9

Time to get testing: swapping between the heavy and light-weight setup on the Torque:ON confirmed weight does matter

The take a look at

That is the Canyon Torque:ON we’re speaking about, a motorised downhill bike, so I headed to the roughest and quickest observe I might discover. I needed to let the bike rip and have enjoyable doing it, however largely I wanted every little thing to be working because it ought to to try to really feel the setup variations. The observe had rocks and roots galore, off-camber sections and a few steep bits, however largely we’re speaking quick and tough.

I adopted the traditional ABBA testing sample. That meant three runs on the heavy 900Wh battery with the water bottle in, adopted by six on the lighter 750Wh  battery and no bottle, earlier than lastly switching again to the heavyweight setting for a remaining three laps.

Facet-by-side it’s clear the 900Wh battery will attain additional up the downtube than the 750Wh… and that actually makes a distinction

What I discovered

A lot to my shock I did really feel an prompt distinction when including 1.5kg to the load of the bike. As a proportion of the bike’s weight it’s fairly small, we’re speaking about including on simply 6% extra heft, which doesn’t sound like a lot. However the bike felt barely much less keen to depart the bottom, however generated marginally extra grip and stability. I doubt this impact would have been noticeable with out the back-to-back testing, and my level is the distinction was very small certainly.

Altering batteries meant adjusting fork, and correspondingly the shock strain too

Extra importantly although, the stability of the bike had shifted dramatically. The fork felt extra sucked down and ran deeper into its journey, and correspondingly the again finish was much less planted. I discovered myself extra off the again of the bike to compensate. I’d added the additional weight ahead of the BB and fairly excessive on the body, which might properly be the principal issue affecting the result of this take a look at.

My plan had been to experience with out touching the suspension settings in any respect, however I had so as to add 8psi extra air to the fork after the primary run to stability the bike out once more.

Eradicating 1.5kg of weight excessive on the bike did affect the dealing with, however the hot button is to regulate your suspension accordingly

Weight issues

So, there’s definitive proof! Properly, type of. I’m considering that weight actually does matter on a mountain bike, however it’s extra about the place you place that weight. The large battery sits simply as little as the smaller 750wh energy pack, however it stretches significantly greater up the downtube. At the least it does on the Canyon Torque:ON.

Mixed with the high-position water bottle it produced an extended second arm and that utilized extra turning drive on the bike. And bingo, the fork compressed extra and tousled the setup on the bike. I’m guessing, however I doubt the 1.5kg weight distinction might have been felt if positioned proper on the bike’s centre of gravity, someplace near the BB shell. 

Proper, I’m off to wrap some lead sheeting to my downtube, take away the valve caps from my wheels and fill the tyres with hydrogen.