Wait! The MTB weight conundrum…

20 Feb 2021

Reading Time: 5 minutes

The prototype bike came off the line, ended up in a box and was in my hands within a day. A few days later I was out riding on it, working out all the little things that needed correction – hardly anything.

A few days prior there was much stressing, after the frame was weighed at the factory and the number that came in made us all not so happy. And so the folly began.

Several hours of discussion, emails and whatnot, followed by many hours of 3D CAD work, and weight had been reamed out of the frame. We had target weights in mind and now we were pretty much on them. But the stupid thing was as a complete bike, the entire package was well within the scope of a 5.5″ bike, sub 30 pounds. And that was with the ‘obese’ prototype frame, the ‘wrong’, heavier rear shock, and the last of Marzocchi’s coil/air 44 forks (the new ones are lighter).

So what was the fuss? Simply put, paper numbers.

The mountain bike world, driven by the magazines and internet forums where every rider with a PC and a broadband connection is suddenly an engineering expert, has been lathered into a(nother) frenzy; in this case the old weight frenzy one. I for one, do not buy it.

You see, back in the late 90’s when the Trek carbon Y bike was the lightest FS bike on the market, a friend had one and we used to ride a lot, and I do mean a lot. Somewhere along the line, he realised that the ideal weight for a dually was around the 25 pound mark (the Y was just under). This was based not only on us riding all sorts of stuff but spending a lot of time actually riding, ie. turning the cranks. This number was not some arbitrary number, there were many sub 25 bikes on the market (sporting 4″), it came from his many years racing MX machines, since he was a kid no less. The idea behind the magic 25 lbs was that if you go lighter, especially with the not so great suspension of the time, the bike became skittish over the sort of terrain you tend to point a dually ie. rough stuff.

To this day I still can not fault the logic and having ridden lighter bikes since then, I still feel the same way.

Light. Cheap. Strong. Three words that most out there seem to have forgot you can only have two of and depending on the two you go for, the end result could be a little scary. Setting aside the carbon fibre thing going on right now and the ‘too light and it’s skittish’ factor, trying for 25 lbs or less for a 5.5 bike seems somewhat…. well, daft. Why? After having ridden the ‘obese bike’, as I like to call it, and feeling that the bike handled and pushed really well just the way it is, I am feeling that the 25 pound rule could not be more true and with more suspension, please add a little more weight to the frame.

And here’s why…

With more travel, you ride harder.

As you ride harder, you go faster.

Harder and faster, you hit and plough things more often.

Treat a light aluminium frame like that often and if it’s not up to the task, it’s going to fatigue and…. break; not to mention that it might be nervous to ride. Even if it is up to the task, it will fatigue faster. Pretty simple and we see it happen all the time. Also, all that ploughing and hitting throws a bike around and it’s better to have a heavier bike that holds its line than a lighter one that does not.

Light. Cheap. Strong. Pick two and I bet they’ll either be Strong and Light or, Cheap and Strong. Now you can have the first but that’s going to cost you big. You can easily have the second but most people will bleet endlessly about the added heft. See the conundrum?

There is a third option though. Build a frame that is Strong and Reasonably Light. ie it’s up to the task of realistic riding by avid riders but then spec it properly, not by the beans. Doing this will give you an odd mix of Affordable (and I say affordable as ‘cheap’ is not an option for a vehicle easily capable of landing you in hospital), Strong, and Realistically Light.

The issue here people want to look at the individual numbers… the paper numbers, so what’s the frame weigh? I say forget the frame and look at the whole package, like teams do when they build race cars, or boats or space shuttles. If the frame’s been designed well in the first place, the overall cost of shaving a few hundred grams more from a frame, is only one piece of the puzzle but in terms of longevity and stiffness, can be far more costly than speccing a slightly better wheel set or bar/stem combo that saves the same, if not more weight.

And there’s the folly. Those that bleet about frame weights then usually go and throw cheap components on it that add significantly more weight to the bike (they spent all their cash on the frame), not to talk about all the unnecessary crap in the saddle bag and the 3 odd kilos of water on their back. Meanwhile those same people, driven by some of the tools in marketing, demand lighter bikes that will cost them less but wonder why the damn things break.

There I was with a prototype frame that by the numbers was outside our goal but when built up with the production build kit, was well within reasonable, not only by my account but others I ran the number by. The bike rode fast, was stiff and felt super planted – not skittish. After much talk was had about how people will want to know the frame weight and after having gone through all that, I finally said no we won’t; because the bike’s a total package, the sum of all its parts, and this prototype proved it.

So while people endlessly bleet on and on about how much this frame weighs and that frame weighs, I sit back amused to watch these same people turn up with their expensive light frames (because Light and Strong = not cheap, remember?) laden down with heavy components, big packs and a mobile workshop, making them as heavy as the guy next to them. So to help these poor misguided weight obsessed souls, here is what I am calling G’s simple and easy light bike program that will help shed those unwanted grams from your bike in order of expense:


A: Most expensive:

1: Do you really need full suspension? If all you ride are tame trails, stop being soft, get a hardtail.

2: Get lighter wheels. Light wheels means decreased rotating mass and that makes a huge difference to acceleration.

3: Look at the way you ride and then look at the parts on your bike. Do you need all those heavy AM/FR parts if you mostly ‘just ride around’. Replace then with something lighter and better suited to your actual use.


B: Not so expensive:

1: Get rid of all that crap in your saddle bag…. and get rid of your saddle bag. Instead get a good light multi-tool and micro pump and put it in your pack.

2: Do you really need several Powerbars and 3 liters of water to go for a 2 hour ride? Really? Try smaller and less and eat and drink properly BEFORE you ride.

3: Take your lights off during day rides!


C: Dead cheap:

1: Do a big poo before you ride. There’s at least 1 pound in that.

2: Stop eating donuts. You sit on bike, so therefore you are part of the system that needs propulsion. The cheapest (and healthiest) way to lighten your bike is to drop a few pounds off yourself.

3: Shut up and ride and stop sitting on yer duff reading paper numbers. Doing this you will achieve the weightloss from point C3 above automatically and get you stronger, meaning a little extra weight will not worry you.


Now get to it.

Disclaimer: I write this article in the realm of the everyday rider, not the elite racer, pro or otherwise. If you ride several hundred k’s a week, and live to race, every gram counts. But then if you are that person, professional or otherwise, money tends not to be an issue when it comes to getting the tools you need – you’ll spend what you need, nor is longevity, as you’ll replace your equipment seasonally.



Copyright 2023 Gerard Thomas. All rights reserved.

I've run mtb events, distributed some legendary brands, ran my own cycling clothing brand, designed bikes and was a GM and head designer for a famous but sadly now extinct mtb marquee; and after 20 odd years I decided riding bikes was more fun than working with them.
Over that time though, I wrote (and some wrote for me) a lot of stuff about bikes, on blogs and the like. Some was good, some, well... not so much. Rather than loose it all when I shut everything down once and for all, I have kept some of my favourite, and more popular pieces here for... prosperity?
I also am working on new pieces as well...

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