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[Webby the Bear]

Thanks for the detailed responses. So to sum up in laymans terms.

The gears and engine braking are what is used to slow the bike cos the brakes are essentially useless at these speeds it would appear due to the high power to weight ratio.

[Mr Gav]

Can a bicyclist explain the box full of neutrals / engine braking importance in bikes. Don't know anything about bikes but interested what happened here 

I've not ridden a bike at anything like the level of performance of these guys, but the principles I was taught by my old man some 50+ years ago still work I think ....

On a bike the power/weight ratio is high, as is the brake ability/weight, the first enables you to do wheel spins with ease, the second to lock the brakes with ease. Light weight of the bike is some of the problem

When trying to slow down from high speed on a bike you are VERY cautious regarding the use of the front brake[highlight/] as several things happen if you over do it ..  front brake locks up.... you not only lose the ability to steer but the bike nose dives (even with modern anti dive geometry), the back end gets very light and the rear wheel "may" lift of the ground, and not necessarily in line with the front wheel !! you are now in a great position to go straight over the handlebars ....  not a good idea TBH

If you apply the rear brake excessively then the rear wheel locks up and you are simply sliding across the ground with very little braking effect, the maximum braking effect is by slowing the rotation of the wheel without it skidding.......   THAT is what engine braking does with maximum efficiency, the momentum of the bike over the ground causes the rotation of the wheel which is resisted by the engine compression, no chance of a lock up (unless the engine seizes) and a high degree of stopping power .. which can then be augmented by the bikes brakes applied very carefully.

No engine braking because the bike is in neutral, either through mechanical failure or rider error means the brakes have to do everything, and they simply cannot achieve it.

To a large extent the same thing happens driving HGVs but for a different reason.. you NEVER, EVER clutch in then brake.. the clutch is ALWAYS engaged whilst the brake is operated ( except at very slow speeds obviously) to obtain maximum engine braking at the rear wheels, this is caused however not by light weight but by the heavy weight causing a large momentum value that the brakes alone would struggle to oppose.

It may well be that things have changed with modern bikes, and if so a younger biker will no doubt correct me, but that's how I was taught, and rode , many years ago .....

It`s not really an issue on good roads as the front brakes have plenty of feel and are quite strong, from high speed there is plenty of weight transfer to help keep the front tyre nailed to the road. Most riders hardly use the rear brake unless it`s wet in which case it helps balance the bike.

That particular corner where Guy Martin crashed is mostly engine braking anyway so I`m told by a lad who follows the TT closely so it was never going to end well with a box full of neutrals.

New T-shirt is out anyway 

[Migv6 le Frog Fan]

Thanks for the detailed responses. So to sum up in laymans terms.

The gears and engine braking are what is used to slow the bike cos the brakes are essentially useless at these speeds it would appear due to the high power to weight ratio.

No. The front brakes are very powerful indeed. Engine braking on its own is used if going down a couple of gears to knock off some speed for a pretty fast bend without needing to hammer on the front brakes. Unexpectedly finding neutral will cancel this though, as well as unsettling the suspension from where the rider expects it to be. For example, when accelerating the weight will transfer rearwards and load the rear suspension while unloading the front. Braking does the opposite. Engine braking will have the affect of mild braking, and neutral will unload both front and rear suspension .

[Nick W]

Thanks for the detailed responses. So to sum up in laymans terms.

The gears and engine braking are what is used to slow the bike cos the brakes are essentially useless at these speeds it would appear due to the high power to weight ratio.

No. The front brakes are very powerful indeed. Engine braking on its own is used if going down a couple of gears to knock off some speed for a pretty fast bend without needing to hammer on the front brakes. Unexpectedly finding neutral will cancel this though, as well as unsettling the suspension from where the rider expects it to be. For example, when accelerating the weight will transfer rearwards and load the rear suspension while unloading the front. Braking does the opposite. Engine braking will have the affect of mild braking, and neutral will unload both front and rear suspension .

It also means that there is then no power available to drive the bike through the bend, which is as bad as it sounds.

[Migv6 le Frog Fan]

Yep.