WEIGHT & WHERE TO WEAR IT...
This article is NOT about loosing a few pounds after Christmas...
This article is about gearbox weight compared to the derailleur system weight.
Bikepacking, Gravel racing and Adventure touring, this was called "Mountain Biking" in the 1980's. Now Mountain biking has split into many different sub-groups, Downhill bikes that weigh 40lbs that need gravity and 30lb dirt jump bikes that defy gravity.
Road cycling has started to split away too, from the Ultralight Tour and winter Cyclocross bike to the Disc wheeled "Gravel Racer".
For most people they just want to ride with their mates. And all of this is making touring cool again. For this reason Mountain biking has gone back to its roots. Rigid fork, of balloon tyres for comfort and load carrying capacity. However riders spend a lot of money to lighten components yet the more expensive derailleur does not mean that it will last longer.
The Lightest Option?
For reliability, one could ditch gears altogether?
Singlespeed is a great low maintenance option, however One is restricted to on tyre selection.
Riders are choosing wider tyres for comfort, control and grip. Wide tyres make it harder to push the tyres around when singlespeeding.
Building a singlespeed can potentially save you 1.0Kg in component weight. This would build a bike (with suspension) that weighs 11.5Kg
If you want to load up with luggage, then singlespeeding looks like a less attractive option, but it is possible.
Back to Gears then?
You will see from the table how the weight breaks down into components.
The total weight of a derailleur system is typically 2.3Kg, making a typical bike with suspension about 12.5Kg
Hub gears weigh slightly more, but put more weight at the back of the bike.
The two Pinion Gearbox weights are 2.75Kg (for the 12speed C-line) or 2.95Kg (for the 12Speed P-Line) adding 450g-650g more than a derailleur set up.
This additional weight builds a full gearbox bike to about 12.6 - 13.2Kg
Hair and Tortoise..
Now this looks like the gearbox has lost on weight, however if you put these two systems into the same environment, the gearbox will keep going and win
The derailleur drivetrain was invented in 1928 and works perfectly fine for road bikes where gear shifting is not impaired by sand and mud. A lot of design and engineering has gone into improving the rear derailleur, but this system is still exposed to the elements and mud.
The derailleur has become the mechanical Achilles heel when long distances and trail conditions turn bad. The gearbox has all of its workings in an internally sealed bath of oil, so there is nothing exposed that can go wrong.
With the combination of Gates Carbondrive belts, this drivetrain just keeps working for 10,000km until it needs servicing and with a 5 year guarantee, that is a lot of trouble-free miles.
Comfort in tyres tyres:
It now crosses the boundaries between "bikepacking" and "gravel-racing". Sure you can ride a gravel bike 700x35C on the South Downs Way.
Gravel racing is fast but with 700x35C tyres you will get battered on terrain larger than cobbles. Some people get obsessed with weight to the extent of sacrificing comfort. This is not neccessarily a good thing for 100miles+.
If you can choose a frame with wide tyre clearance, you can always fit thin fast tyres on and have extra mud clearance.
For long distance riding, I am going to argue the point that everyone should ride a rigid with at least 2.0"(51mm) wide tyres.
Why you ask? At the 70mile point, 7hour of riding your body will start to suffer and complain.
By using 2inch wide tyres you will have the speed and comfort.
Rotational? Wait? what?
It is worth noting that rotational weight is the killer when cycling.
Between 2.3" (850g typ) and 2.1" (600g typ) you can save your self 500g a pair of tytres.
250g on a rear tyre does not sound like much, but the comfort benefits deminish after 2.1" wide. Rear tyre grip is down to tyre pressure and shifting your weight to the rear tyre.
Potential saving 500g (feels like more though) and plus sized tyres can be 800g saving.
Riders rely on suspension forks now as an essential part of their kit. However are a can let you ride beyond your ability, saving you from those little points where you might lack of concentration.
You can ride carbon fully rigid and save your self at least 1.0Kg. A Maxle fork is more important to keep your fork riding straight.
Potential saving 1000g
Strong, Cheap, Light. Pick 2. The only way to get a Strong Light frame is to pay a little more. But the benefits of a strong carbon frame is that you can save upto 1000g. To pass CEN 4130 Steel frames typically weigh 5.5lb (or 2.5Kg) while carbon frames can weigh 1.0Kg. Putting more carbon = more strength. To pass CEN with a 120mm fork our frames are 1.4Kg (or 3.0lbs) This is over 1000g saving.
Real Weight Savings:
We think nothing of carrying 2.0Kg of water and carry most of that around for more than a few hours. 2Kg on your shoulders for 10hours will have fatigue setting in. Put the weight on your bike. Water weighs the same in ml as grams, so 700ml water bottle weighs 700g (or 0.7Kg).
Rotational weight savings on tyres could be 500g or more.
At the end of the day rotational and carried (on the body) weight noticable than static weight.
So tyres -500g
Water - 600g
Forks - 1000g
Frame - 1000g
At the start of this article I mentioned the extra gearbox weight of 650g. A frame weight saving of 1000g is a good starting point. Water and tyres weigh a further 1100g. This is 2.1Kg without loosing front suspension.
Changing to carbon forks would have you save over 3.0kg.
So in reality the additional gearbox weight of 450-650g is not really an issue for bikepacking and long distance riding, when you can easily save more weight by changing other components.