Jump to content

Losing traction on stock tires (stock SM tires)

Recommended Posts

I've experienced a strange loss of traction a couple times on my bike and was hoping someone might have some insight on the cause.

It's an '18 701SM with the stock ContiAttack SM EVO tires. Less than 1500 miles on them and pressure set at factory recommended 29psi. Suspension settings are adjusted to factory "standard" settings. Sag has been adjusted slightly for my weight so that the measurements read what's recommended in the manual. I'm in SoCal, it never rains here so the ground was completely dry, I went back to check the area to see if there was dirt/oil/fuel on the ground and there was nothing.

The issue is during a turn at slow to moderate speeds (1st-2nd) gear I've completely lost traction and had the bike step out on me, both with the front tire and with the rear. Both times I was starting from a stop light. The first time I was making a left turn, half way through the turn while I was leaned over, as I started to roll the throttle on the rear tire went. Slid maybe 6 inches then hooked back up and then rode fine, that one startled me a little. The second time it happened I was making a right turn from a stop. Again, half way through the turn just as I started to roll the throttle on in 1st gear it broke loose. This time it was the front tire and it slid 12-18" before hooking back up, scared the crap out of me, I almost dumped it. I got home and first checked the tire pressures, I had been riding around the neighborhood for a bit so they were warm. Ended up reading about 37psi. I let them cool overnight and checked them while cold, read about 30psi. 

I have since dropped the cold pressure down to 28psi. At this point I'm not sure what else to check. I don't want to go messing around with damping adjustments at the moment because I'm not exactly sure how those adjustments would effect the handling, or how adjusting one end will affect the opposite end. 

Hopefully someone with suspension knowledge reads this and might have some insights/pointers for me as to how to go about fixing this issue.

Share this post


Link to post
Share on other sites

Sounds like you're just plain breaking loose.  Cold tires are more susceptible to this but it can also be caused by dirt, oil, coolant or any other contaminant on the surface of the pavement.  Road paint is usually slippery as well.

Adjusting damping will have almost no effect on static handling like going through a flat corner.  Adjusting the fork height and rear sag will effect how the bike responds to inputs and will have minor effect on traction but when the tires let go is primarily determined by contact patch and the amount of traction available from the road surface.

Share this post


Link to post
Share on other sites
22 minutes ago, Marylander said:

How much riding experience do you have?

6-7 years

11 minutes ago, turbo dan said:

Sounds like you're just plain breaking loose.  Cold tires are more susceptible to this but it can also be caused by dirt, oil, coolant or any other contaminant on the surface of the pavement.  Road paint is usually slippery as well.

Adjusting damping will have almost no effect on static handling like going through a flat corner.  Adjusting the fork height and rear sag will effect how the bike responds to inputs and will have minor effect on traction but when the tires let go is primarily determined by contact patch and the amount of traction available from the road surface.

That's what I was figuring. The surface I lost traction on was clean and dry, and there was no road paint.

I'm going to play around a little bit with tire pressures to see if that alleviates it a bit, I do think they were over filled and reducing their contact patch. 

Share this post


Link to post
Share on other sites

Little update. I've ran the tires now at 28psi on a 80 mile ride. I didn't lose traction in the same fashion yet, I've been extra careful on turns. I checked the tire pressure right when I got home and was reading about 34psi hot. I'm starting to think that my issue was overfilled tires combined with only slightly warm tires. Smaller contact patch and tires not at a proper temp. Earlier when I lost traction the first thing I did was feel the tire and it was warm, after the longer ride when I got home I put my hand on the tire and it was considerably hotter. I'm sure the cooler concrete/asphalt was a factor also.

Share this post


Link to post
Share on other sites

So, I don't want to offend you here but I feel like you're doing yourself a disservice by thinking of this as a technical issue with bike setup (tire pressure, sag, damping, etc). I'm not saying bike setup isn't important but I think you would be better off looking at it as a skills issue (specifically not being sensitive to conditions) and work on the skills. Make a point to practice some cornering, braking, and such at the beginning of every ride on cold tires. Ride in the rain/cold. I also think riding a dirt bike is a good idea as you'll become accustomed to sliding both ends and won't find it such a pucker inducing thing if it does happen. Anyway, just my 2 cents.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×