High temps, low grip? | GTAMotorcycle.com

High temps, low grip?

MyNameIsBup

Active member
Was riding around today but for some reason I just didn't feel confident leaning the bike over. It constantly felt like the bike was going to drop out from under me with any real lean angle. I went home to check things out and can't see anything wrong with the bike.
So I'm now wondering, is it the +30 degree temperatures we had today making the road feel "greasy", or is it just in my head?
 
That's the idea. The road surface temp was probably in the 40s or 50s and that's where the slickness comes from, though I wouldn't expect it to be noticeable at street speeds.
 
Tires would stick like glue. That's y people use tire heaters. The road also includes a percentage of old tires (I.e. Rubber), so heat would increase grip. All theory though, this is my first summer and everything feels good.
 
Tire pressure was at 32 psi on a ninja 250r. It was only really noticeable at "slightly aggressive" speeds.
 
Could have just been all the people running their car air conditioning (being the first really high humidex day of the summer) and some water droplets collecting along the road in certain places. Maybe some oil droplets, who knows, generally the grip should be better when hot though, up to a certain point of course.
 
Also on a Ninja 250 and no issues in the heat. Our stock tires supposedly are not that great but I would think it's a non-issue at street speeds. I guess just make sure your tire pressures are correct 28F 32R as per the manual....
 
Never noticed it due to heat... tire pressure?
 
Tires would stick like glue. That's y people use tire heaters. The road also includes a percentage of old tires (I.e. Rubber), so heat would increase grip. All theory though, this is my first summer and everything feels good.

It can get greasy when it's hot. Too little or too much heat are both bad. I don't bother but when it's really hot, increasing your tire pressure will lower their temperature.
 
Hmmm....maybe you tried leaning more than you normally do thinking you have more grip?

If so, you may have come to a point in the tire profile that rounds off quickly, creating that feeling of "dropping out".

Some tires have steep profile changes past a certain point for quicking flinging into corners, but past that point they are actually quite stable and sticky. Just the transition is abrupt and feels sudden.

Other thing could be if you leaned too far on the street after not warming it up...in which case they could actually have been "relatively cold" for your angle.

On a hot 30+ day on the track I am not comfy getting my knee down for the first 5 or 6 turns...that's a deflated tire running 29 PSI after some hard braking into the corners.

It usually takes 2 laps on street / track tires in 22C+ temps to get them sticky like rails.

That greesy feeling only comes after 20+ laps in a row.

More than likely I would say you had too much lean for either "cold" tires or an aggressive tire profile intended for quick fall ins.
 
Thanks everyone for your input,

The tire pressure was spot on when I checked them. I'm now pretty sure it was just me leaning the bike further than I'm used to at too cold a tire temperature. I live very close to snake road where I felt the slippage. This is my second season and as I get more confident, I'm starting to realize how much potential the little Ninjette has in the corners. I've started to adopt a more aggressive riding style which is probably why I never noticed the slipping before!

Now I've got to get myself to a track to see what all the fuss is about.
 
Change those POS stock tires for BT003's before you take it to a track or you will regret it.
 
Thanks for the advice. I'm interested to see how a good set of tires affect the handling.

What do you mean by slippage? Obviously the bike has only two tires, so you were getting feedback from the front or the rear, and at which of the three points of the corner was it occuring? Entry, Apex or Exit?

I'm going to bet that you could do a lot more with that bike if you knew how to properly enter and exit a corner, so have you done any additional reading or research since you passed your M2?

Try Sport Riding Techniques by Nick I. and Kenny Roberts, and the Keith Code DVD A Twist of the Wrist II. They'll both help you clean up your steering technique, foot peg weighting, counter steering and brake input as well as others that will prepare you for the track and improve your street cornering.

Anyone who has ridden a dirt bike can tell you what happens when you overwhelm the available traction, you do a face plant in the mud, get up, get back on the bike and ride it back to the trailer, but on the street, you may be talking police, tow truck and insurance claim after the hospital visit. It sucks to find out that you did it wrong while waiting for new fairings.
 
I'm going to say it's a combination of your oem tires, suspension, and body position. Get some tires before you go too crazy
 
I'm going to say it's a combination of your oem tires, suspension, and body position. Get some tires before you go too crazy

I can out ride him with knobby tires on my KLR. Maybe he should mount some Kenda 270's on it so he can do better in the twisties. ;)
 
I've recently finished reading A Twist of the Wrist II. This is the book that started to make me think about how I was cornering and probably why I'm trying to feel out higher limits! I've been leaning into the corners with my body weight but not hanging off the bike as I think that's a little excessive for the street and my riding ability.

It's the rear tire that feels twitchy, like it's about to collapse from under me. This happens at max. lean angle around the apex of the corner while gently feeding in the power. Now when I say maximum lean angle, remember this is relative as I'm not leaning that far over. My tires show me I still have at least 1/2 - 3/4 inch of rubber left on each side!

Maybe it's what alaywa said and it's a sudden tire profile change that's psyching me out but I don't want to push it any further on the street as that's just asking for problems. That's why I want to get to a track so I can figure this stuff out in a controlled environment.
 
How much do you weigh? Is your suspension set up? Are you using stock tires?

If you weigh more than 150, set up your rear suspension using the tool.

Stock irc tires are known for known for being horrible, but mine gripped okay at 5+ degrees (although I never hung off unless it was at least 13 degrees.) I got my strips down to a couple of mms of each side. With that in mind, any tire's better than stock tires. Just make sure not to get too lean-happy (I wouldn't recommend pushing it to the edge on the street with bias-ply tires).
 
Now to think of it, during the winter I put on A LOT of weight due to an injury. I weighed 145 before and now am a little over 160. The spring preload is still set at the softest setting! Is this enough to cause the problems I'm having?

The tires are the original irc tires that came with the bike. Even though I've heard nothing but bad things about them, surely they and also I can't be that bad..., right? :)
 
At this point its probably not a suspension issue at all. I have seen riders like JohnyP (on this forum), have the softest suspension, wobble his zx6r like an old lady out of turns, shred tires like no body's business, slip and slide all over and still set amazing lap times.

The reality is he knows how a bike should feel, understands the limits, and can even slide a little and know when the rear slippage is too much.

I would opt for better street / track tires, head to the track, drop your tire pressures as per advice from technicians at the track then take it easy and gradually progress throughout the day. Hard braking and accelerating will heat up the tires over 2 laps, then they should be sufficiently warm to lean right to the edge of the tires. The feeling is strange, but you'll notice once they are properly heated up you don't get that slipping feeling anymore, they feel SOLID under you!

I can take the same tires I felt solid on one day at the track, and the next day getting off a ramp on the highway not feel as solid on them, simply put they aren't hot enough for a full lean.

When you go around a track you heat up not only the centre of the tire, but the edges, so after 10 to 15 right hand turns at high speeds with hard braking into the corners, that's when it's hot enough!!!

Watch my video OP and you will see I made a silly mistake to push my tires following better guys on better tires. I learned how long it took to get my tires up to temp because I also went a lot of times to the track with a buddy. He became a rookie in the SOAR league and dramatically improved to better me. In our first track outings, he used to take as long as me to get his tires up to temp...street/track tires, and less aggressive riding, and no tire warmers took him 2 + laps, like me. On the day this video was shot, he was on Pirelli Super Corsa's, medium compound, 31C temps, + tire warmers. He was able to get his knee down by the second turn......I simply could not!!!!

I also know on Cayuga track for example, the left to right turns are about 1:3, and the left side of my rear tire doesn't feel as solid as the right until I am into the 3rd lap. After that, the next 20 laps are solid and never feel greasy.

I would say, riding on a highway straight up, then trying to throw it into an off ramp with some exagerated style will definately feel weird, party due to a new sensation as you push your max, but also because the tire is cold. You think it's hot but it really isn't hot enough for max lean!!!

Even on the track you will need to drop PSI from stock about 4 to 6 PSI. For example, I drop my front tire from 36PSI (street stock) to 28, then once hot they get back up to 31 with increased hot air pressure inside the tire.

On the track the techs will tell you to drop drop your pressures to whatever example but hot! So again 30C air temp and some putting about on the street is NOT a hot sticky tire.

Once you get on the track OP and you do a good 20laps touch your tires, feel how sticky they are and then you wont try any cowboy moves on the street again.

Enjoy my rear tire slip and the subsequent fall......start from 4:40 to see the start of my second lap. I shouldn't have pushed so hard on my second lap....and I made a few mistakes pushing so hard trying to keep up with my own ego. So I suggest you progress comfortably and get to know your machine. Worry about set up later. Maybe by the end of the day get a track tech to help you set it up and go out to feel the difference.

[video=youtube;lNQc9pD_y14]http://www.youtube.com/watch?v=lNQc9pD_y14[/video]

By the way, track set up is stiff and hard....not so good for the street, and at this point, you wont be shredding rear tires to even detect if you have a soft set up! But after some experience, as you push the limits, once it is set up to be stiffer you will appreciate a stiffer rear sock, stiffer forks (to stop from bottoming out under hard braking, etc), and I'm not sure a 250 has rebound dampening, so I'm not sure you will be able to counter the seesaw effect mid-corner, or even if you ever experience that at your skill level. Don't sweat set-up yet.
 
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