Cycling UK Forum

Q: are modern bike tyres compatible with some of the modern formulations of tarmac ?

I've found quite a few new surfaces (up to a couple of years old) to be very slippery even in the dry and with no fuel spills evident. Some seem to have more binder at the surface than the chippings.

Would an old technology tyre of real rubber be better than a silicone rubber formulation now sold by virtually everyone ?

Tyres give you grip by deforming in shape to match inversely the shape of the road surface you are cycling on. So if you are lacking in grip then that suggests you're either running a tyre compound that is too hard or you pump up your tyres too much.

I think it is doubtful that old rubber is any softer than synthetic rubber, synthetics can be soft or hard depending on the intended use.

Having reported a load of problems on FixMyStreet.com in January, half of my on-road commute is now on newly resurfaced roads (I exaggerate slightly, but they've not finished yet). I haven't noticed any loss of grip, but the smoother surface is nicer to ride along.

There is a new kind of road surfacing being used which contains polymers, and which if laid too cold is vulnerable to plasticiser diffusing to the surface. This makes the road extremely slippery. It's can be almost as bad as black ice. I've heard of whole groups of riders coming off, only to hear from a bystander that motorcyclists have gone down too, and cars skidded, since the road was resurfaced. The highway authority, when informed, does nothing, asserting that traffic will scrub the slippery stuff away. Maybe it will, but only in the areas where four wheels go!

The fault is in the road, not your tyres. Log such defect on fillthathole.

I had an awful winter for slipping and sliding, but in most cases it was diesel. The local farmer spills copious amounts of the stuff down the lane (which has four 90 degree bends) and cars/lorries shed it on roundabouts. I'd hate to be a motorcyclist - imagine 80bhp going through your back wheel and hitting a diesel slick.

CJ wrote:There is a new kind of road surfacing being used which contains polymers, and which if laid too cold is vulnerable to plasticiser diffusing to the surface. This makes the road extremely slippery.

Its tempting to see this as the reason for the relatively recent crop of road signs warning of the slippery nature of newly resurfaced stretches of road. It caught my attention because it used to be the case that old and worn smooth surfaces were regarded as slippery...
Does anyone know if the warning signs are located "on merit" or just when the council legal advisors are feeling nervous?

CJ wrote:There is a new kind of road surfacing being used which contains polymers, and which if laid too cold is vulnerable to plasticiser diffusing to the surface. This makes the road extremely slippery. It's can be almost as bad as black ice. I've heard of whole groups of riders coming off, only to hear from a bystander that motorcyclists have gone down too, and cars skidded, since the road was resurfaced. The highway authority, when informed, does nothing, asserting that traffic will scrub the slippery stuff away. Maybe it will, but only in the areas where four wheels go!

The fault is in the road, not your tyres. Log such defect on fillthathole.

This is apparently known as negative texture surfacing and the surface is smooth (negatively textured!) with voids for drainage, finer particles in the coating are expected to wear away with the larger stone component becoming visible. There have been many instances of people claiming to have skidded on these surfaces but they apparently meet the requirements for skid resistance.

The best practice guidelines for resurfacing works recommend that warning signs are put in place until the surface has had time to wear (dull but may be useful to someone https://pronet.wsatkins.co.uk/RoadsCodes/documents/doc_thin_surfacing.pdf

If you do a search for negative texture surface there are a few civil engineering sites that discuss the topic. Personally I've noticed one brief skid a couple of weeks after the surface was laid but I find that I now break earlier at that junction, so maybe not such a bad thing

My own experience of these road surfaces is pretty negative having lost a friend and club mate recently due to a fall on such a surface. It has since transpired that this stretch of rural B road in Suffolk has so far caused at least 7 bikes, 1 pedestrian (the paramedic slipped as he stepped off the ambulance), a motorbike and several cars to slip/crash, resulting in everyything from superficial damage, bruising, cuts and the sad aforementioned death. The latter is subject to a police investigation and inquest, so am awaiting the findings.

I also have anecdotal evidence of other similar stretches of road in Suffolk which have caused club colleagues to slip, or at least feel their wheels sliding, you know that horrible stomach turning feeling....