Front Tire Cupping

[wardie]

My bike is a 1995 K 1100 RS. I only have 3K on the Bridgestone 023's and run 37 psi in front and 41 psi rear. I know they cup due to the shape of the road etc. but it's starting to be noticeable at 3K? which in my mind it shouldn't. I just did almost 150 miles in Southern Ohio corner carving and thought they wouldn't cup as quickly but they did. I'm going to run 41 psi for a while and see if it slows the cupping.


The PO had Bridgestone 023 and I wonder if its the shape of the sidewalls that causes it to cup more than maybe a Michelin?


Anyone in America where we ride on the right have any experience with a tire on their RS that didn't cup or cup as quickly?

[Blue]

My front tires cupped all the time until I started running 42 psi cold.  Now they do not cup at all regardless of brand and model of tire.

[wardie]

Thanks Blue I'll get the tire up to 42 and see what happens.


I'm bummed only 3K and its really showing dang it.


I'll report back thanks

[beemrdon]

42 psi did it for me too (front and rear).

[Filmcamera]

I use 40 front 44 rear as recommended by Chris Harris - no cupping so far.

[wardie]

In looking at the tire I noticed the aspect ratio to me is conducive to making the tire cup. I have a ounder curve a Bridgestone 023. I am told the new T30 Evo would be better suited. I did pump up the front tire to 41 psi as some have suggested and it definitely helped but it changes the feel of the bike .

[blackie1]

hi Wardie
i have just sold my 1992 K1100LT and my front cupped out reasonably quickly also.


most of my riding is medium to high speed corners with only a few straights so am probably spending almost 30 per cent of my time in some sort of corner.
I ran 38 psi rear and 36 psi front , both tyres are pirelli sport demons which I think are a fairly soft compound tyre.
tyre pressures up in the 40's just felt way too hard in my opinion.


I think the K1100 is pretty heavy on the front tyre at the best of times and  if you start man handling that big beast through corners at higher speeds you really have to apply some heavy duty counter steering to make your corner in time.


 so bearing that in mind you are probably exerting quite a bit of lateral force on the front.
another thing to bear in mind is your front fork is now 20 plus years old.
when was the fork oil changed out last?

[wardie]

I push it in the corners and she tracks well. IDK about the fork oil but think you're right about changing oil.


I was surprised about the cupping. I did two  hundred miles of hard charging at a MSTA weekender thinking boy I've really rounded these buggers and was disappointed that it started cupping. I saved the tire from the PO and same tire had the same cupping issue. It was so bad you couldn't turn left without in tipping in aggressively.