Chip seal vs hot mix?

[Brian407]

Pretty much all we have to ride on down here is chip seal, apart from in town. I dont have any issues with it, wet or dry. Just make good tyre choices and you'll be fine. I find i'm more uncomfortable on asphalt in the wet, especially just after it starts raining. Often you can see the rainbow slick of diesel, oil and rubber leaching from the surface, especially if its been hot prior to raining.

But, as always, (and as a recent thread has shown us) Ride to the conditions, and your level of experience, and you'll be fine.

[slofox]

Overall I probably prefer hotmix but then most of the roads round here, as others have pointed out in other regions, are chip seal.

What I do notice though, is that the quality of the chip seal round here (and other places too I bet) varies to hell and back. If it's in good condition - no eczema, loose bits or tar bleeds - then I treat it the same as hotmix. If it's a bit crappy then I slow down and don't ask too much of the tyres. A good case in point is the short hill section of SH 23 between The Tron and Raglan. There are some bits of seal on that stretch that are in dreadful condition and are treated accordingly.

Let's face it, on the highway, you need to be aware of the road condition and never take anything for granted.

[NONONO]

Chip Seal will always break up, specially the way it's laid here. So what you end up with is lots of loose gravel on the center line, with a loose spread around the edges. Now if you fancy riding on that rather than asphalt, good on yer, but hope you are riding a Motad. For speed and handling leave it to the blackstuff every time, or experiment and see where that gets you.
It's not all about getting the most rubber to the surface, but also about how the surface moves once you have the rubber down.
As was said earlier..whats on the track?

[p.dath]

Not the reason.... More rough = more friction.

Bet not. If this were true then more tread not less (i.e. slicks) would be the way forward. Don't think I'll be fitting knobblies to the thou any time soon

davebullet is correct - but rough at a microscopic level. The four primary factors that cause grip are the sum of:

• Free surface energy causing cohesion (and stickiness)
• Micro-hysteresis, which is tyre deformation around the surface it is pressed against
• Macro-hysteresis, which is bulk tyre deformation, often caused by hard braking, aceleration or cornering loads
• Tyre wear or shearing

"Slicks" tend to have more of all four of the above qualities, compared to a road tyre with "tread" - but slicks still mostly definitely want a rough microscopic surface to work at their best.
Put it this way, if you were at a track and came off, and walked away in your leathers, and then at a second track you came off and your leathers were ripped to shreds through abrasion - then you could push the bike and tyres much harder on that second track.

Consider this, which does a tyre have more grip on - super slick ice or a higher abrasion surface like hotmix? When you have a rougher surface you get the added benefit of micro-hysteresis.

yea but the less tread you have the longer it takes to heat up and maintain that temperature. so you would have bikes fanging the shit out of their bikes to get that temp. and then they find a wet patch or oil etc.. and it's all over red Rover.

I should warn you that schrodingers cat has considerable experience in racing circles. Consider his words to be coming from an expert.

Tyres are a super complicated device.
A road tyre heating up is typically to do with carcass flex more than the tread. Tread on road tyres can often be used to dissipate heat - like a radiator. Having less tread is not likely to make a road tyre heat slower. [Racing] slicks take more effort to heat than road tyres because of their compound and construction, as opposed to the lack of tread - and that compound and construction is considerably different than your average road tyre.

Once the tyre is "hot" I don't think it would cool so rapidly as to cause any significant loss of traction that a small wet patch could cause. But oil - now that is another story. Lubrication and friction are not friends.

Consider what actually makes your tyres hot - its when the tyre experiences a lot of bulk deformation - lots of bending - such as under hard acceleration, hard braking, or hard cornering. Do you see how its the bulk tyre deformation that causes the majority of the heating effect?

[Brian407]

Chip Seal will always break up, specially the way it's laid here. So what you end up with is lots of loose gravel on the center line, with a loose spread around the edges. Now if you fancy riding on that rather than asphalt, good on yer, but hope you are riding a Motad. For speed and handling leave it to the blackstuff every time, or experiment and see where that gets you.
It's not all about getting the most rubber to the surface, but also about how the surface moves once you have the rubber down.
As was said earlier..whats on the track?

You say that like we have a choice of riding surfaces.... Now I'm not sure about the Auckland area but down this way we cant just ring up the local council or NZTA and request a particular road surface for todays ride. Also not sure about the quality of your "North of the Bombays" chipseal but down here we dont have significant problems with seal 'breaking up' if it's layed properly, and for the most part, it is. That is, of course, if the Auckland region hasnt gobbled up all the roading funding with some silly bridge project, or providing 'on demand' road surfaces to placate riders with little experience on a variety of different mediums.

[Old Steve]

I think I slow down on Chip seal because I have this subconscious feeling that it'd be worse to come off on chip seal than on hot mix.

[Brian407]

I think I slow down on Chip seal because I have this subconscious feeling that it'd be worse to come off on chip seal than on hot mix.

Youd never get fast enough to do any damage on a Hyosung 250 woud you.??...

Sorry, couldnt resist.... but seriously, your right, the chip seal is a little harder on the body (still got the jacket and leathers to prove it) but it's still quite rideable at legal speeds with good rubber.

[skippa1]

If you are trying to compare good chip seal with good hot mix, IMHO hot mix is the better of the two as it is generally a lot smoother. My view - grip is pretty much the same wet or dry. How long it has been wet for is more important to me, a road that has been dry for a few days then gets a brief rain is ratshit, riding my last sports bike, I have scraped pegs on a wet hot mix and chip sealed road(same road - Whanagmoas) that has been wet for a few days. Depends on your tyres, ability, oil on road, whether the chip has lost its edge.........it goes on. I also dropped the same bike on a dry chip sealed road and wrote it off. Ran out of luck or skill or ability or whatever.............

I should add, that pushing it that close to the edge is not something I now recommend. You're better off taking it a bit easier and waking up tomorrow.

[Ocean1]

Chip seal is cheap, nasty and dangerous for bikes. Was originally supposed to be a temp measure, but as all things, once we accept it it becomes permanent.
http://youtu.be/6qfcn7q2LS4
http://youtu.be/jsha7q5miqY

Largely correct. Typical spec' for hotmix = $70/sqM, chipseal = $12/sqM.

Although chipseal can be done "right", (where "right = stable for several years) as is obvious from comparisons between typical NI applications and most SI examples.

[MSTRS:Me]

If you are trying to compare good chip seal with good hot mix, IMHO hot mix is the better of the two as it is generally a lot smoother.

And because of that, your suspension is not working quite so hard all the time. This is why riding on asphalt makes the bike feel so much more 'planted'. The suspension's job is to keep the tyre/s in contact with the road, and (within reason) the smoother the surface, the better the contact.
In addition, rain tends to run off asphalt easier than it does on chip (which traps water in the valleys between the stones) so wet asphalt provides grip levels better than wet chip.
The other problem with chip is the stones themselves. When freshly laid, the stones have sharp edges and are generally quite angular. Grip is huge, but the stones are not yet stable in the holding medium (tar, bitumen, whatever) and tend to get flicked out to become the loose scree we all hate meeting. By the time the road surface is 'stable' the stones have lost that sharpness and grip is slightly compromised. Of course, where the chip has released there are now totally smooth sections of 'tar' which are lethal in the wet. Eventually, tptb put a patch in to repair, leading to a less consistent surface.
How many smooth, shiny sections or repair patches do you ever see on asphalt?

[Brian407]

And because of that, your suspension is not working quite so hard all the time. This is why riding on asphalt makes the bike feel so much more 'planted'. The suspension's job is to keep the tyre/s in contact with the road, and (within reason) the smoother the surface, the better the contact.
In addition, rain tends to run off asphalt easier than it does on chip (which traps water in the valleys between the stones) so wet asphalt provides grip levels better than wet chip.
The other problem with chip is the stones themselves. When freshly laid, the stones have sharp edges and are generally quite angular. Grip is huge, but the stones are not yet stable in the holding medium (tar, bitumen, whatever) and tend to get flicked out to become the loose scree we all hate meeting. By the time the road surface is 'stable' the stones have lost that sharpness and grip is slightly compromised. Of course, where the chip has released there are now totally smooth sections of 'tar' which are lethal in the wet. Eventually, tptb put a patch in to repair, leading to a less consistent surface.
How many smooth, shiny sections or repair patches do you ever see on asphalt?

So you're saying we should avoid riding on chip seal. Well thats gonna work well for many, Those of us not blessed with perfect roads might as well sell our bikes now and wait for the tooth fairy to asphalt all our roads.

Here's an idea.... What about learning to ride properly, on the variety of road surfaces we encounter every day in New Zealand? or is that too radical an idea?

[schrodingers cat]

Here's an idea.... What about learning to ride properly, on the variety of road surfaces we encounter every day in New Zealand? or is that too radical an idea?

Next you'll be telling us to ride to the conditions, within the level of our ability and to take personal responsibility.

I suggest you push off quick mate. Your sort is not welcome here


Todays useless fact - the ideal aggregate in chip seal has been crushed with the aim of achieving 7 faces.

Poorly crushed gravel is more likely to ping out

[Brian407]

Clearly...

[MSTRS:Me]

So you're saying we should avoid riding on chip seal.

Where the fuck did I say that?
I know which one most would prefer to ride on, and why. But we get what we get, and we just get on with the job of riding.
And break out the tissues when we get a lovely, smooth, grippy section of asphalt in a tight, twisty bit...

[The Singing Chef]

And break out the tissues when we get a lovely, smooth, grippy section of asphalt in a tight, twisty bit...

You will find that a sock is much more convenient whilst riding. Tissues can be hard to carry around.