[Matt]

For those of us who are now riding in colder temperatures, this is your reminder: Cold roads don’t grip!

I got a good reminder of this on Sunday (air temp was about 9C btw).
Approaching a major intersection (4 lanes each way, plus left turning lanes) I was paying attention to the car in front of me and not the traffic signal, I noticed it turned yellow only when I noticed my riding partner (ahead and in the left tire track, I in the right) slow down.

I over reacted and stomped the rear brake, which locked up the rear wheel and sent the back of the bike sliding outwards. There was no warning about the loss of grip, no tire noise, nothing. It felt like the bike was sliding on kitchen tiles. I did what I’ve been trained to do on bicycles and what I was told NOT to do on motorcycles, I released BOTH brakes. The bike straightend out hard and quick, and I reapplied my brakes, with a lot more emphasis on the front. I came pretty close to entering the intersection (with cross traffic about to start). Pucker moment to be sure.

I’m not entirely sure that releasing the back brake was the wrong thing to do in this case. Because the rear end was sliding so far wide, it could have snapped and high sided me when I let off the brakes, but if I hadn’t, I certainly would have ended up in the lane beside me…

I’ve ridden in cold a fair bit recently, and I was just finishing 100km day trip when this happened. But the sudden loss of traction still surprised me. So remember, as it gets cold it gets even more important to keep your eyes up and leave yourself lots of braking distance (to say nothing of keeping the corning speeds down).

-Matt

[Phil]

I do not understand!
First of I am glad you are ok and commend your skills!

Ok, Cold air will harden the rubber of your tire a little bit and therefore they will grip less, however you ahve been riding for about 60 miles and rolling friction will warm your tires.
However 9C is not cold, 9C is 50F. For you as a rider of course 50F is cold but for oils, water and rubber there should not be much of a difference between 70-60-50F, besides the effect from above.
Also, the pavement approaching a traffic light has more oils and buildup since cars usually stand still on it.
If I am completely off track on this one, could someone explain it to me?

[bob250]

50 F isn’t mind numbing cold and I wouldn’t think it would have that much impact on tires griping the road. Is it possible you locked the wheel over something on the road? Anyway, glad it was only a pucker moment and nothing worse.

[Matt]

An oil spot is very possible.
If I missed noticing the yellow right away, I’ll fully admit I could just have easily missed a spot of oil on the otherwise dry road. It would also explain the suddenness of the loss of tracking (my bike is pretty good about telling me how the tires are handling).
—
“The two seconds between ‘Oh S**!’ and the crash isn’t a lot of practice time.”

[razor]

You said you overreacted and stomped the rear brake. I imagine that was the cause of the lockup more than anything else.

On the road I hardly use the rear brake. The rear brake is basically useless when you’re braking hard.

[Phil]

I would not go as far as calling the rear break useless, 25% of breaking force is still 25%!
Makes all the difference between hitting something at 20mph or being able to stop right in front of it!

[Andrew]

I use the back break a lot for speed trimming but I use both if I want to stop.

[Candice]

Me, too, I use both breaks to stop.

[razor]

True, that’s why I said basically useless and not “completely useless.” I guess I should have been clearer. When I say I hardly use the rear I mean I’m still using it but not using much force.

I have known many a person that went down because they panic, hit that rear brake and lock it up. It seems so odd to me because most of the braking power is in the front! What are they thinking?! Bad habits…

[fotobits]

Who’d a thunk it?

[Matt]

The rear brake is, as stated, between 25 and 40% of your stopping power, but more importantly, it allows you to load up the front brake faster, allowing you to use more front brake sooner.

The amount I stomped on the rear brake was not more than I have in the past without locking up the wheel. It was faster and less progressive than I’d like, but not to a level that I think it would have caused the lockup on its own.

The more I reflect, the more I think the sudden loss of grip was caused by having the tire right near the limit of adhesion and then catching some oil – especially given how smoothly the bike slide once it locked up (having locked up the tire several times in the ERC I do know how this bike feels when the back is locked and sliding, and this was waaay slicker – puppy on fresh waxed kitchen floor level of smooth slidding).

—
“The two seconds between ‘Oh S**!’ and the crash isn’t a lot of practice time.”

[Author]

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