So, on the back of the roadie drafting thread. How much benefit am I likely to see if I sit behind somebody on a Sunday ride?

I know it benefits TDF riders etc, but they are not fat middle aged blokes in an ill fitting t-shirt?

Depends on your speed really, but the faster you are going (and still pedalling) the more the benefit. Up to about 35% less effort for the same speed iirc.

Loads. It’s a big effect, even at lower speeds.

Could someone who knows about these things also confirm the effect on the leading rider? The other thread implies it’s a benefit if anything, due to reducing effects of drag. I always assumed there was a negative effect on the front rider…

I always assumed there was a negative effect on the front rider…

Only that hes putting in a big effort for the guy behind. Fine if you are doing it for each other or for your team. Sucks if the guy behind doesn’t return the favour.

Ther’s a slight positive effect on the leading rider as it lead to a cleaner airflow around the back of them, reducing drag. All a bit more marginal though, and the following rider needs to be really close.

If you’re at the front, it’ll feel hard, benefit or not!

Yep, that pretty much sums up my experience!

Is this true even if I am much taller/wider than the person I am following?

Reason I ask is I have never felt a marked benefit when sitting behind somebody. At 35 odd percent, I would expect it to feel like it does when you change direction and lose a headwind.

hooli – you’re unlikely to feel much benefit IMO/E unless you are going at a bit of a pace at least.

This higher the speed and the bigger the person in front is the better.

You should always feel a good benefit, I know on our club hammerfest I welcome the shelter.

If your sticking out like a sail or not that tight on the wheel then the effect will lessen. Crosswinds can also play a part and in that case where possible and if it’s safe to do so you should echelon.

Having done team time trails with a power meter, I’m using about two thirds of the power when getting a good draft.

Sit on the front and pull your tripe out for 15 mins, then drop back into 3rd wheel. You’ll soon feel the difference. The faster you go, the more noticeable it is, IME.

A third sounds about right, but you do need to be going at a reasnoble pace and within a few inches of the rear wheel, it’s much less the further back you go. There’s a bit of a multiplier as well, in the middle of a peleton it can drop to almost half as the group effectively moves in a nice moving bubble of air with only the riders on the perifery doing the work, a bit like a constant tailwind.

Yes, you really need to be well tucked in. You notice how small the pocket of air is when when trying to get on the back of the line having peeled off the front, stray too far back and it can become a real problem.

Even fat grannies in baggy gear on shoppers with wicker baskets will benefit. It’s a big difference.
There is also a help to the rider in front as mentioned, but that is much less noticeable.

You’ll know when you’re in the zone when the air rushing past your ears stops rushing and begins buffeting because you’re in the turbulence of the rider in front. As others write above, the effect is even greater if you’re in a crowd of riders; you really will find yourself blasting along at a pleasing rate. I read a story once about a regular Mamil who joined a main road and suddenly found himself caught up in a big peloton; he said that he went fast but soon got very hot.

Is this true even if I am much taller/wider than the person I am following?

The size of the windbreak up front makes a big difference. I’m 5’11” and 88kg and I went out for two road rides last time I was in the US – once with a 5’7″ 59kg bloke and once with a 6.6″ 115kg bloke. Drafting the smaller bloke made next to no difference, but the bigger one was great 🙂

Look on youtube for roadies drafting behind trucks at motorway speeds, obvs taking it to the extreme, but shows that it definitely works.

… or that northern chap with the sideburns who likes a brew breaking the bike speed record drafting a truck. Probably still on 4od somewhere.

I’m pretty sure I read or saw something recently that there is a slight negative for the leading rider? something along the lines that the cleaner air over the trailing rider cause slight suck!

Oh and look up, I was drafting a guy in a race last year only to look up and see that he’d come off the back of the leading bunch. Don’t worry I did punch myself in the face. 😳

Can confirm that big folk drafting wee folk have a tougher time of it, although I’ve been told it’s OK if the person behind gets in a decent aero position.

I’d love, even a slight, suck when I’m out on the bike.

Fnar fnar….

Ah! My coat! Much obliged

I never notice the advantage. I just start thinking the pace is a bit slow. Then I go to overtake… That’s when I realise it’s not slow at all!

I’m pretty sure I read or saw something recently that there is a slight negative for the leading rider? something along the lines that the cleaner air over the trailing rider cause slight suck!

I read this too, but can’t vouch for the source. It was probably on here. I dare say if there is a difference then it’s got to be minimal.

Best demonstration is down a long hill; tuck in behind someone and you’ll have to brake to stay there, move out to pass them and see how your speed changes.

You can use the effect to slingshot past each other and go quicker as a result…

What do folk reckon the mph difference is? If I blow out my backside solo at 2hr/18mph, what speed group ride might that equate to?

It doesn’t equate really; it depends on how fast the other guys go, how many of them are there, how well they ride together.

Basic rule of thumb; no group ride can go faster than the slowest guy can manage…

I guess it works for people on MTBs as well then?

I guess it works for people on MTBs as well then?

On road: yes but the speeds are generally far lower so not the same effect
Off road: I’d hate to follow someone that closely off road!

About the only time I’ve done slipstreaming off-road is on flat fireroad trails and even then you have to watch out not to get a mouthful of grit or mud.

What do folk reckon the mph difference is? If I blow out my backside solo at 2hr/18mph, what speed group ride might that equate to?

Depends on the size of the group but if there were 6 of you then you’d be over 20mph. Average speed for my road race at the weekend was 23mph for 47 miles. Including some hills and a brutal headwind.

I’m pretty sure I read or saw something recently that there is a slight negative for the leading rider? something along the lines that the cleaner air over the trailing rider cause slight suck!

This was the prevailing wisdom but then they tested it and found there is a benefit to the leader of having someone follow. Chris Boardman did a feature on it during the ITV TdF coverage last year. IIRC it was one of the the “marginal gains” discovered by BC to help their team pursuit squad.