[chrisotherwise]

Hi All,

This Sunday I switched back to my road bike after the winter using my gravel bike. All was going well until I reached a downhill corner at which point my tyres lost all traction on the road – and I mean all traction. It was like I was on ice. I tried to brake but was not able to in time, and my bike slid out from under me leaving me with some very nasty grazes on my arm and leg. 

I cycle about 7K a year and have done that particular corner hundreds of times – nothing like that has ever happened before. I’m struggling to understand what happened and how I might avoid such a fall in the future. The morning was warm and humid and there had been a tiny amount of rain earlier on after a couple of dry weeks.

I’m now nervous to get back on my bike (well the grazes are still too bad anyway).. but I’m wondering if anybody else has experienced similar, what you think the cause was, and what you’ve done to try and mitigate when riding again afterwards.

Topic

[Rendel Harris]

chrisotherwise wrote:

One thing the road did have was lots of recently repaired patches with fresh black tarmac. Perhaps they could have contributed?

Absolutely they could have. Tarmac is a petroleum-based product and its surface can be very oily when it’s newly laid. This is particularly the case after rain (you said there had been a little rain earlier?) when water ingress can make oil seep out of the compound. This is a well-known problem in Grand Tour races when the asphalt is freshly laid in preparation for the peleton passing through and rain can turn the roads into a skating rink; either last year or the year before I think they had to neutralise part of a Giro stage due to this effect.

[stonojnr]

fwiw in that area, yes

fwiw in that area, yes absolutely its normal, its like a lowland heath sandy area, most of the b roads have alot of sand at times,, it just blows of the heathland and fields,or when it just rains washes off the heathland & fields onto the roads instead, with all the grit and rubbish that goes with it.

couple of good examples in the area, and theyre roads, theyre not farm tracks, or off road sections.

https://maps.app.goo.gl/zkyq953qcdeqU2zg6

https://maps.app.goo.gl/Cygt3nxaGE9LHrB8A

[stonojnr]

ah know that road, havent

ah know that road, havent been up that way specifically for nearly 6months but have ridden it fair amount over the years, and if its the corner I think it is, Im sure it had a load of potholes on the side edge back last year, and the camber felt pretty odd too, like the road was sinking or just falling away.

I know you can get up some speed approaching it, and yeah I remember picking a line to avoid the holes, but just didnt feel comfortable at all, it was one of those whoa that doesnt feel right sketchy moments, I might have hit a bump or a stone too.

some of thats everyone seems to drive that road like theyre still on the A12, and Ive had people try and overtake me there, which just adds to the unease, so I just use other routes if I can.

[chrisotherwise]

Sadly very normal. And the

Sadly very normal. And the sand contains loads of evil little shards of flint. 

[chrisotherwise]

Tyres are brand new Conti GP

Tyres are brand new Conti GP 4 season – the only type I’ve found that stands any chance against the huge amount of flint on our local roads. I did over 6,000K on this type last year without any problems.

One thing the road did have was lots of recently repaired patches with fresh black tarmac. Perhaps they could have contributed?

[David9694]

This isn’t one of those “aren

This isn’t one of those “aren’t GatorSkins terrible” threads is it? Isn’t the complaint that they acquired a smooth glossy sheen? 

I took a similar-ish sounding spill a few years ago. It’s a dip the road with a bend at the bottom that I normally tackled the other  direction.The bike just seemed to get away from me and accelerate, I braked, but I couldn’t make the bend and hit a wire fence with posts at a shallow angle – wrote off my front wheel and never trusted the frame again (CF).  A few bruises,  not a show stopper and hopefully not for you either.

As I understand it, a dry spell sees a lot of car gunk builds up on the surface and a bit of rain “activates” it and makes things slippery, though not so bad as to give the effect you describe.  The other time this happened to me is on newly painted double yellow lines, which were damp – I rolled across them and was promptly dumped on the ground with the bike seeming to just vanish to the side. 

[Rendel Harris]

mark1a wrote:

The filler caps are often vented to allow air to escape as the liquid expands in warmer temperatures, and air to be let in as the fuel level goes down.

Ah, interesting. One would’ve thought it’s not beyond the bounds of possibility to create some sort of U-bend or one-way valve fixture that could let the air out/in without letting the fuel out as well?

[wtjs]

This is interesting- there

This is interesting- there are very many buses passing up and down here all the time: school buses, Stagecoach etc. and there are several 90 degree corners, but this diesel spill problem doesn’t exist. Maybe it’s because the bus garages where they must fill up are several miles away in both directions.

However, while cycling back to Garstang from Lancaster, I did see a big BMW go down on a trail of diesel which came onto the main road from a farm side road- and that was a straight section of road coming towards me and the rider was behaving perfectly sensibly, just ambling along

[OnYerBike]

chrisotherwise wrote:

Thanks for all the kind replies. I was back on my bike yesterday and went and had a look at where I had my fall. No obvious diesel on the road or anything else for that matter. Lots of sand around and lots of tractors. […]

Is that normal for that spot? Pretty sure sand (and/or other sand-like substances) is commonly used to soak up spilled diesel, so if a load of sand has suddenly appeared in that spot, it would be indicative that there had been a diesel spill there. 

[mark1a]

The filler caps are often

The filler caps are often vented to allow air to escape as the liquid expands in warmer temperatures, and air to be let in as the fuel level goes down.

[Rendel Harris]

Yes, I think it happens

Yes, I think it happens directly after they’ve filled the tank, don’t know why though.

[chrisotherwise]

Thanks for all the kind

Thanks for all the kind replies. I was back on my bike yesterday and went and had a look at where I had my fall. No obvious diesel on the road or anything else for that matter. Lots of sand around and lots of tractors. But nothing different from anywhere else I cycle. Very strange. This is the spot:

https://w3w.co/glassware.subsets.masts

I’m still worried that there might be some issue with my bike and have been very very careful going into corners. Hopefully I’ll get some more confidence back as I ride. 

I put large hydrocolloid dressings on my (very deep) grazes. The speed of healing with these on is nothing short of astonishing. No scab forms, and the wound just heals under the dressing. Highly recommended if you ever get this sort of injury. 

[Rendel Harris]

+1 for diesel; is the corner

+1 for diesel; is the corner on a bus route? They’re the worst culprits though there are plenty of others. Often impossible to see, one of my regular routes takes me past a bus garage and however carefully you scan the tarmac there’s always the risk of missing the “liquid black ice”, particularly if there’s been some rain because the water seems to take away its characteristic rainbow sheen. Not a lot you can do about it except take a line round corners where the filler cap wouldn’t be to give yourself the best chance of missing any trail from a leaking vehicle. Wishing you a speedy recovery and hope you’re back on the bike soon.

[Karlt]

In January I came off on a
In January I came off on a low speed bend just like that – no warning; front wheel just went. Long story short I’m waiting for physios to clear me to ride on my newly replaced hip.

Probably diesel as it was the entrance to a railway station heavily used by buses and taxis. Unfortunately it’s just $#!+ That Happens.

I’m also concerned about a repeat so I’m replacing the road bike with a gravel in the hope that the grip will be better.

[mark1a]

Sorry to hear this, it could

Sorry to hear this, it could be due to a diesel spill. I sometime see vehicles that have been filled to the brim and then it as it turns a corner in the opposite direction to the side the filler is on, fuel leaks from the filler neck, and if it’s diesel, doesn’t evaporate. 

[Author]

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