Measuring tyre grip

[Twilkes]

Lots of data on rolling resistance out there, but are there any tests that can measure how well a tyre grips when e.g. cornering, or on dam surfaces? Plenty of people have described certain tyres as skittish or awful in the wet, but is there any way of objectively backing that up?

 

[Yellow Saddle]

Yes there is a way to do it but unfortunately it requires some specialised equipment, controlled laboratory conditions and plenty of crashes.

Most, if not all reports on "skittish tyres" and "awful in the wet", as you mentioned, are pure nonsense.

In order to make a judgement you would have had to repeated test the tyre until failure and somehow have measured either the slip-out angle or the point where stiction turns into friction under upright conditions. No-one I know has done this. The obvious reason is the equipment required but the other reason is that testing tyres when cornering requires repeated falls and someone who can accurately pin-point the lean angle at the time of slip-out. I don't know anyone like that, not even among my stuntman chums.

 

[Heltor Chasca]

That’s a fun question. Ice? Clay? Water?

Personal experience gets expensive given that decent tyres these days last such a long time.

 

[andrew_s]

The methods of testing tyre grip I've heard tell of are...

In a lab, take a representative bit of flat road surface solidly mounted in a tray, position the wheel & tyre vertically, resting on the road, with a suitably realistic load, then tilt the tray until the tyre slips.
The problem with this is that it's static rather than rolling.
Presumably you could, at considerable expense, do the same using a tilting drum similar to those used for rolling resistance testing. How to get a realistic road surface on the outside of the drum is left as an exercise for the reader.

The other method was real world bike riding, taking the same (downhill) corner at gradually increasing speeds, until "too fast" was reached. The rider wore motorcycle leathers & hip protectors etc. The angle was obtained by a camera positioned so the bike was going straight towards it at the anticipated maximum lean.

A bigger problem is that road surfaces are very variable, and there's no reason to assume that the tyre that's best on the test surface is also best on all other surfaces.

 

[fossyant]

Tricky with road tyres, but harder compounds will sometimes be less grippy than a softer, but quicker wearing tyre.

MTB tyres then it's still difficult to prove, but there are differences with the knobbles - some suited better for dry trails, some better for rocks and roots. I've found the tyres originally fitted to my Trail bike, were quick, rolled well, but got a bit loose on tricky surfaces. The tyres I replaced them with are far better when things get a bit hairy !

 

[andrew_s]

That's usually the case, no matter what the subject - everything is a compromise.

With road tyres, it's a matter of tread compound and casing to give what the manufacturer considers an optimum balance of grip, rolling resistance, puncture protection, weight, cost, and wear life.
MTB tyres have that, plus tread pattern, which adds soft ground mechanical grip, loose gravel mechanical grip, and the losses in knob squirm to be optimised as well.

 

[SkipdiverJohn]

Tricky with road tyres, but harder compounds will sometimes be less grippy than a softer, but quicker wearing tyre.!

I suspect this is because a soft rubber will deform more when in contact with the ground under load, so will "squirm" into the irregularities of the surface and tend to hold the tyre in position more positively.
On the other hand, a hard compound, or a tyre inflated very hard, will not deform as much and so will simply move across the surface without interlocking with the irregularities to any great extent.
The average utility cyclist is not going to push the grip abilities of a tyre to the limit anyway as they will be travelling fairly slowly and not cornering fast, but they will certainly notice if their tyres wear out quickly or puncture easily - so it depends on the rider's priority for the tyre's attributes. For most riders, so long as their tyre is round and holds air, they are not going to even notice anything much about it's performance!
Modern tyres are one of the very few areas in cycling where I think there has been substantial advancement in product performance & quality (the other being LED lighting) , as premium quality puncture-resistant, high mileage lifespan, tyres such as the Marathon are light years ahead of the tyres I used to use in the 1980's. I know for some reason M+ are often much maligned on here (I don't use them personally), but the lighter Greenguard version I have found to both roll well and offer decent grip, hardly seem to wear, and I have gone 18 months on them without a single visit from the Fairy. Aside from the fact they are quite heavy, I see no disadvantage to fitting them, I even use them on my drop bar Dawes. which is a fairly sporty frame although not a true racer. I'd sooner be enjoying a trouble-free ride rather than stopped at the roadside fixing flats, so if a few ounces of extra weight in each tyre is the only penalty I have to pay for the extra reliability, to me it's a no-brainer. I haven't gone nuclear with M+ because the ordinary version has proved to be tough enough.

 

[themosquitoking]

I reckon very few people out there have cahoonies large enough to ride to the point of the tyres loosing grip on a decent dry road surface.

 

[Tenkaykev]

I suspect this is because a soft rubber will deform more when in contact with the ground under load, so will "squirm" into the irregularities of the surface and tend to hold the tyre in position more positively.
On the other hand, a hard compound, or a tyre inflated very hard, will not deform as much and so will simply move across the surface without interlocking with the irregularities to any great extent.
The average utility cyclist is not going to push the grip abilities of a tyre to the limit anyway as they will be travelling fairly slowly and not cornering fast, but they will certainly notice if their tyres wear out quickly or puncture easily - so it depends on the rider's priority for the tyre's attributes. For most riders, so long as their tyre is round and holds air, they are not going to even notice anything much about it's performance!
Modern tyres are one of the very few areas in cycling where I think there has been substantial advancement in product performance & quality (the other being LED lighting) , as premium quality puncture-resistant, high mileage lifespan, tyres such as the Marathon are light years ahead of the tyres I used to use in the 1980's. I know for some reason M+ are often much maligned on here (I don't use them personally), but the lighter Greenguard version I have found to both roll well and offer decent grip, hardly seem to wear, and I have gone 18 months on them without a single visit from the Fairy. Aside from the fact they are quite heavy, I see no disadvantage to fitting them, I even use them on my drop bar Dawes. which is a fairly sporty frame although not a true racer. I'd sooner be enjoying a trouble-free ride rather than stopped at the roadside fixing flats, so if a few ounces of extra weight in each tyre is the only penalty I have to pay for the extra reliability, to me it's a no-brainer. I haven't gone nuclear with M+ because the ordinary version has proved to be tough enough.

After I read your message I went to the Schwalbe website and downloaded some info. It's about 50 pages in PDF format and a very interesting read.

I know that they will promote their own tyres but there is a lot of useful information about tyre / tube /tubeless technology / sealants etc.

The document also mentions that the direction arrows on their road tyres are just cosmetic, not so on their off road tyres.

Link here

https://www.schwalbe.com/en/catalog...Vaw2Bd-jtzrMH_1XURJG6gqyp&cshid=1571213590768

 

[Twilkes]

I reckon very few people out there have cahoonies large enough to ride to the point of the tyres loosing grip on a decent dry road surface.

Yeah you're probably right, although I don't have the same nerve (or naivety!) that I did in my twenties, after having the bike go from underneath me on ice a few times, a front wheel jitter on a wet road corner quite recently, and coming off once from a lack of mechanical maintenance. I started thinking about this topic again by how easy it was to push my wheel sideways on wet paving slabs, although they seemed particularly friction-free, most pavements aren't that bad. So maybe a wet tarmac test might be worthwhile, but yeah, I'm not about to investigate my own particular bike's grip/slide boundaries.

 

[NorthernDave]

As has been said, there are huge differences in road surfaces, and more importantly what's on that surface - rain, snow, oil(!), leaf mulch, etc which makes it difficult to compare.

Perhaps more importantly, grip is also massively subjective. What feels skittish and edgy to one person might be interpreted as giving lots of feedback or having a sporty feel by someone else.

I'm a big fan of Gatorskins and have them on both my road bikes, but there are other people who can't stand them and complain of a lack of grip - I've heard them referred to as "Skater-skins". It's not an issue I've ever encountered personally, but it goes to show.

 

[Shearwater Missile]

Too many variables at play I feel to be of real use. If you find a tyre you like stick with it and get to know what it is like in dry, wet, damp and dare I say icy conditions. Really it is no different to a car tyre IMO. Would you hammer a car in wet conditions if you did`nt know what it drove like. Riders weight and set up would also play a role on handling regardless of the tyre. I always back off on a corner if I think it is going to be damp or greasy. I`d sooner come out of the corner upright than sliding across the road because some report said the tyres were brilliant in the wet !

 

[andrew_s]

Would you hammer a car in wet conditions if you did`nt know what it drove like.

A fair number of drivers drive like they do without any regard at all to road conditions, and seem surprised if it's suggested that they do think about them.
Paying attention to the road is one of the things you learn quite quickly on two wheels - it hurts if you don't.

I used to ride on Gatorskins all the time*, all through the winter without any problems, and I remember stopping one time to pass a car that was upside down all across the middle of the road, having skidded on the ice, and finding dismounting remarkably difficult because of the lack of foot grip (we'd been warned about the car by a policeman at the top of the hill). The driver turned out to be my mate's bosses' secretary, so he got the full info. "I don't understand what happened, I was driving just the same as I always do" she said. His reply was "that's your problem, then".

* I'm on fatter tyres these days.

 

[SkipdiverJohn]

A fair number of drivers drive like they do without any regard at all to road conditions, and seem surprised if it's suggested that they do think about them.
Paying attention to the road is one of the things you learn quite quickly on two wheels - it hurts if you don't.

Anyone who has ever spent time driving older vehicles, including commercials, with no seatbelts, no airbags, no ABS, and on crossply tyres with drum brakes will also pay a lot more attention to road conditions and adjust their driving style accordingly.
Modern stuff is easy to drive too fast like a muppet because you are cocooned in a nice warm box full of gadgets to play with, and you lose that direct connection with what is outside all around you.

 

[Smudge]

As has been said, there are huge differences in road surfaces, and more importantly what's on that surface - rain, snow, oil(!), leaf mulch, etc which makes it difficult to compare.

Perhaps more importantly, grip is also massively subjective. What feels skittish and edgy to one person might be interpreted as giving lots of feedback or having a sporty feel by someone else.

I'm a big fan of Gatorskins and have them on both my road bikes, but there are other people who can't stand them and complain of a lack of grip - I've heard them referred to as "Skater-skins". It's not an issue I've ever encountered personally, but it goes to show.

Very true, a lot a BS gets bandied about when talking about tyres. Very often when someone perceives a tyre to be bad handling, they will make up a derogatory nickname for it like that 'skater skins' you mention, then others will carry on using that tag, many of them not even having any experience of that tyre. You get exactly the same thing about motorcycle tyres like calling Bridgestone Battle Wings 'death wings', that BS tag followed those tyres around for years, yet i used them with no probs whatsoever.
Its all down to to what you consider most important in a tyre and buying a tyre to suit those requirements. Best grip on tarmac always comes down to a softer compound that produces more friction against the road and that always comes at the cost of faster wear.
Personally, i'm with Skipdiver and PP comes top requirement for me, for that i'm prepared to compromise some weight & handling.