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RE: Front Tire Cupping

RePete — Mon, 19 Mar 2012 19:15:42 GMT

Good for you Ibafran. Enjoy those track days. As I said before, I agree with you that cupping is not caused by cornering but by braking in a straight line. You will not cup a tire riding hard in the twisties or on a track. Also I think you will like the 30 psi next time.

RE: Front Tire Cupping

ibafran — Sun, 18 Mar 2012 23:44:06 GMT

RePete (3/15/2012)

[quote]ibafran (1/23/2012)

---skip...

BTW Ibafran you also mentioned the issue of tire air pressure and its effect on handling. You seem to feel that varying from the manufacture's recommendation by more than 4 psi may lead to instability issues. With the cravat that your results may vary, allow me to share my personal experiences on this topic also while I'm still on my soapbox.

I've never experienced a single stability issue running a much lower pressure than recommended. Our R1s call for 41 psi front and rear. Janice and I both like 36 front and rear on the street. At the track a good starting point is 30 front and rear. If the day is below 60 degrees, a few lbs. less will give better grip and above 90 more air works better if you ride hard. These pressures work fine for any bike we have ever ridden as long as the tires are radials. Less air pressure will always improve grip and unless you are really pushing, stability is only affected if the tire is nearly flat. You really only need more than 23 lbs. or so in order to keep the tires from over heating...radials need less than bias plies. We run more air on the street to save the rims from potholes and rocks and we don't need as much grip. I believe Yamaha specifies such a high pressure to just cover their arse. Running 5 lbs. less gives us more grip plus a more comfortable ride on the freeway without any instability.

Thanx very much for the info, RePete.

ALL: Recently, I had this interesting experience. I managed to get on the Autobahn C.C. track. About 4 miles long with 19 turns, we ran it at "Touring" speeds governed by a pace car. I was so busy trying to learn the track that I never looked at my speedo. My GPS recorded a top speed of 88.6mph. Figure 10-12 pace cars with 6 cars in tow apiece. And 2 bikes, me for one and a budd on a BMW 1150RT-type. My budd has a lot of skill and confidence. He had no problem staying right on top of our group. Figure the following times were slightly less than 1 second. Except for me. I was too uncomfortable (read: scared) to be inside 4secs of my budd and the last cage in the pack. My discomfort is largely due to the fact that my Sprint does not seem to have much engine braking compared the the Beemer and the cages. Thus the pack gets out of the throttle sans any brake lights and I roll right up on them before I get a hint that they are slowing. So, I have to brake harder than I like for a turn that I know nothing about and have no brake points for. Now for the best part:

Not only do my tires have street psi, but the bike has been sitting in a blazing sun all day in an 80f parking lot. We came off the track after 4 laps for a brief rest. "Brief" means that I barely had enough time to pull my shorts out of my a$$ and tell my pace cager that I am having fun and that the pace is about right for me. I knew my tars were a bit hard and I was going to air down a little. That's when I noticed that we were going out again. Another 4 laps with a slightly quicker pace and I am ever so slowly falling off the pace. My tars are surprisingly devoid of feel which I assume is due to too much psi. After the 2nd session, I immediately grab my tire gauge and find: front-46psi and rear-so far off scale that I am amazed that the stick didn't get ejected from the case. Aired down to front32 and rear36. And I barely got this done before we headed for the track again. Bike felt much better. But I was mentally done for the day. I stayed with the pack and finished the session. Never did learn more than 6-8 corners. Rode enough different lines due to poor skills to find most of the worst dips and track anomalies. I wasn't so slow that the pack behind me caught up. Stuff I learned:

Autobahn C.C. is a really, really nice track. It is fairly fast and laid out for cages rather than bikes. It is mostly flat and doesn't have a series of esses. But, you do want to ride it if you can. Reminds me of Road America where the turns come one at a time and drivers don't get worked to death in a sustained tight and technical effort.

I don't think that I ever want to ride a new-to-me track without 2-3 "parade" laps in order to get some decent orientation for possible brake points, turn-in points, and what kind of turn follows any short chutes. I didn't even know about any "outs" or escape routes or any places where leaving the track on a bike would be an especially poor idea? I was mentally "lost" on the track for a lot of time.

During the 3rd session, my budd got a little tired combined with a little brave. So he missed an apex or two and went wide a cuppla times. If passing had been allowed, I might have tried one on him figuring that it would have been easy for him to get it back anytime/place as my errors were ubiquitous. I am glad that I was at the back and didn't slow him any.

Finally, I am going to screw up my courage and try 30psi fore and aft on my bike on an Easter track school day that is drawing near. My nearly bald in the center front tire shows no sign of cupping at the edges. While my track corners were fast, I didn't have much threshold braking. Maybe it is braking that is largely responsible for causing cupping?

RE: Front Tire Cupping

RePete — Thu, 15 Mar 2012 20:48:05 GMT

ibafran (1/23/2012)

Anybody wear out a set of tires at the track and get cupping there? Maybe it is a street only phenomena?

Yes, I've destroyed many, many tires on various race tracks...I should know I changed them all myself and I have the scars to prove it. I never had any cupping on any of those tires. The only time I've ever cupped a tire is in general street use with little cornering involved. It was always the front tire only and I believe braking was the culprit. Cornering seems to eliminate or at least mask the cupping.

RE: Front Tire Cupping

RePete — Thu, 15 Mar 2012 18:37:17 GMT

ibafran (1/22/2012)

Last year, I rode from chicagoland (elev. about 800 feet) to Divide, CO (elev. about 10,000feet) and didn't experience a significant change in PSI that made me make a note to be more careful. My best WAG is that I should have had PSI near 50+psi-rear/40+psi-front (up from stock 41R/36F) due to such a change in elevation. And I don't recall anything like that during my pre-ride checks.

I could be wrong (I was not a physics major), but I believe that the air pressure on the outside of the tire will have no effect on the pressure on the inside unless it changes so much that the volume of the tire is affected. My personal observation is that temperature has a much greater affect. Just a minute or two of direct sunlight after leaving the shade will add 2 or 3 lbs. of pressure.

RE: Front Tire Cupping

art miller — Wed, 14 Mar 2012 19:03:07 GMT

I've had 5 motorcycles, two BMW's and three Yamaha's. Never had a cupping issue with any of these bikes. Tire pressure is likely the most contributing factor. Better to boost the pressue a couple pounds higher than the manual suggests. If riding two up or loading a lot of baggage adjust the psi accordingly. Hard breaking into a corner will contriute to cupping. Better to down shift prior to entering the curve and use the brakes sparingly.

Never ever mount a directional tire in the opposite direction. Most tires are radial ply and built to be run in a specific direction. As stated in an earlier thread, reversing the tire could result in tire failure.

RE: Front Tire Cupping

RePete — Sun, 19 Feb 2012 20:31:16 GMT

I changed the slippers on my baby this weekend. I spaced out this time and they had 7k miles and should have been changed 2k sooner. The rear was down to the wear bars in a couple of places but the front was way past that. Still there was no cupping, of course there were no grooves left at all on 80% of the tire with just a shadow in the center. So there you have it. Just run the tires until they are slicks and you'll eliminate the cupping.

RE: Front Tire Cupping

michaelcycle — Sun, 19 Feb 2012 15:55:41 GMT

Deadman has cupping causes pretty well covered. It can be almost anything. I am religious about inflation and cupped every front tire on every bike I have ever owned to some degree or another. I live on a very twisty backroad and use a lot of front brake. My bikes are well maintained and when cupping gets very noticible I change tires. I used to get upset about it , now I just change tires.

Take care, Mike

RE: Front Tire Cupping

ibafran — Mon, 23 Jan 2012 13:12:44 GMT

Talk about 'brain fade'. I finally remembered Oct 2011, Dave's column goes on about Rake & Trail. And he doesn't say anything about cupping. BUT he does say near the very end, "Don't change tire pressure by more than 4psi unless an expert knowledgable about your bike says otherwise."

That quote made me remember more than one track day instructor telling their charges to "drop your psi to 30, fore and aft from whatever your street psi is." I am going to go way out on a limb here and say that I agree with and support Dave on that idea. Dropping a rear tire to 30psi from street stock 42psi just gives too much squirm, slip angle, and weirdness for most non-track riders to deal with. Dropping the front to 30psi from a street spec 36psi is also too much in my book. It would be better to drop it to 33psi and ride it a while to get used to the feeling. Then drop some more if one wants to try 30psi. My limited experience tells me that Dave's 4psi is just about perfect for me. 32psi on the front is pretty good. Soft enough for me to feel some slip angle creep. Yet hard enough that the tire goes where I want it and does not wash away without good feel that I am approaching its limits. I do not as yet ride so well that I like a mushy tire.

What has the above got to do with cupping? Well I had a fairly new front tire (2-3k miles on it) at the track for a day last summer. And I looked at the tire at the end of the day and saw no sign of cupping. If it was starting to cup from being abused for 120 miles of track, I couldn't see it? But, it is possible that I don't know how to see minor cupping if it was starting there? I shoulda asked one of the track rats but wasn't smat enough to know to do that at the time. Aside: From my POV, I would think that an expert on my bike would also need to be an expert on my fitted tire to recommend dropping psi more than 4psi to me?

Anybody wear out a set of tires at the track and get cupping there? Maybe it is a street only phenomena?

RE: Front Tire Cupping

sgtslag — Mon, 23 Jan 2012 06:18:15 GMT

I don't know jack about tires, Ibrafan, but the older tire styles (late 70's) are still available. I remember riding on them (plenty of sipes, creating almost a grid pattern), in the rain, back in 1982. I and a buddy were riding 55 MPH, in the rain, on Interstate. We had no traction issues, which scares me, today! I was riding a 1974 Suzuki Titan 500 two-stroker, mosquito killing fumigator... )

Now I ride on Pirelli MT66's, exclusively (proven wet traction, four days riding in heavy rain, two-up, with the bike overloaded with luggage), but I really wonder whether those old tires (still available today...) were just as good, traction wise? Price is not much different between the Pirellis and the old, vintage tires. Got too much depending upon the traction, so I won't be testing the vintage tires anytime soon, but I do wonder. Cheers!

RE: Front Tire Cupping

ibafran — Sun, 22 Jan 2012 23:11:48 GMT

I have no idea what Dave considers 'minor road debris'? Let's suppose that sand is 'road debris'. How would one determine when the amount of sand is 'minor' enough that tire tread would handle it?

Also, on page 9 in Downtime Files, there was a letter about 'Altitude and Tire Pressure'. Because I don't ride in mountains as much as I would like, I don't have the experience. If anyone is having a significant change in tire PSI due to altitude, I would like to hear about it?

Ok. This is a tire thread and I am wandering slightly away from 'cupping'. But, I see no harm in collecting related info here. And changes in psi should affect cupping in significant ways, right?

Dave goes into carcass stiffness. Anybody got any data on the likelyhood of stiffer carcasses being more/less prone to cupping? It would be nice to know that cupping is a pure tread pattern problem and has nothing to do with carcass construction. Or maybe it is a pure compound problem exacerbated by a certain kind of usage?

Ok, I have vowed to do a little investigation during sunday biker breakfast in the summertime when the bikers are plentiful. I'm going to look at a lot of tires and talk to a lot of bikers and maybe learn something about cupping.

Ever notice those tires at Deal's Gap aren't cupped? Granted, I was only looking at the ones showing the most shredding. Maybe cupping is a flatlander or gentle thing and and it doesn't occur where riders get to spend a lot of time going hard in the twisties?

Also, AFAIK, I have never cupped a rear tire. It is a front tire only thing for me. And any cupping that I have had has been on a 'modern' high speed rated tire that looks like a slick with a few rain troughs cut in it having no 'sipes' whatsoever. 'Sipes' are the little side cuts off the main rain grooves in my little universe. The 'ribbed' front tire treads of old never cupped on my old bikes.

Anybody wanna take one for the team and ask Dave about this stuff? Right at the moment, I am not in the mood to contact Dave about all this. And I don't think that he will volunteer anything here, if he even reads this place or gets someone to report on me/us.

Aside: My Feb issue came with smudged ink in a cuppla places and real light print in another. I sent a note to Production Quality Control via the contact tab on this forum about the smudged ink but didn't mention the light print. So, if your issue is less than flawless and has light ink, you can mention it to the editors. this is the first time that I ever got a rag that wasn't perfect, production-wise.

RE: Front Tire Cupping

RePete — Sun, 22 Jan 2012 21:23:09 GMT

ibafran (1/22/2012)

However, on tread design he does say,"....more grooves will make the tires less likely to lose their grip over minor road debris." Anybody care to enlighten me in an understanding of how this might be true?

I'm in your court Ibafran. This is news to me, and I don't agree either. Dave must be envisioning the small debris will find its way into the tread sipes and thus not interfere with the tire's contact with the pavement. I don't have the Feb, issue yet, but sipes are there for one reason only...to channel water out from under the contact patch to avoid hydroplanning. On dry pavement, they serve only to lessen a tire's grip because there is less rubber on the ground and a smaller contact patch. They race with slicks for a reason. Sipes provide zero traction if they are filled with debris or not.

RE: Front Tire Cupping

ibafran — Sun, 22 Jan 2012 11:20:12 GMT

Feb. 2012 issue, Dave spends his column on tires without mentioning 'cupping'. So, no insights on that topic.

RE: Front Tire Cupping

Bobo the Clown — Fri, 20 Jan 2012 15:42:33 GMT

Strange, no poster mentioned tire pressure as a culprit. CHECK PRESSURE OFTEN!

The road crown as a cupping cause is real. Here in the US the cupping appears on the left side of the front tire, in the UK it appears on the left side of the tire. The middle of the road is always going to be a bit uphill from the road edge. That means you will have more contact with the inside edge of the tires. Alone, maybe no big deal, but combined with soft tires, variable air pressure, and alignment...

RE: Front Tire Cupping

hitechluddite — Fri, 20 Jan 2012 13:05:01 GMT

My theory is the more expensive the tire is the more likely it is to cup! My Harleys and old goldwings used good ol Bias ply 90 profile tires that give good service for the $ and cupping is/was not an issue. My BMW K bike and 1800 wing used high dollar tires that tended to cup on the front and didn't give as many miles even though they cost more. It's ironclad logic that "the man" has a break point where it has been shown that if you are willing to shell out that much $ for a tire you're willing to replace it early!

On the serious side I found running the pressure on the front tire on the high side helped a little and some tire of course are worse than others...

RE: Front Tire Cupping

drummer — Sun, 15 Jan 2012 16:34:39 GMT

[quote]drummer (1/15/2012)

[quote]deadman (1/15/2012)

Ok, thats' probably confusing and provocative enough for now...where's the synthetic vs dino oil thread...[/quote]

Okay, them thar is fight'n words...

Deadman - You're correct with your comments as always. Thanks for the input.[/quote]

RE: Front Tire Cupping

drummer — Sun, 15 Jan 2012 16:33:58 GMT

[quote]deadman (1/15/2012)

Ok, thats' probably confusing and provocative enough for now...where's the synthetic vs dino oil thread...[/quote]

Okay, them thar is fight'n words...

You're correct with you comments as always. Thanks for the input.

RE: Front Tire Cupping

deadman — Sun, 15 Jan 2012 13:24:58 GMT

FWIW, here's my thoughts on ft tire cupping: It's inevitable, and for the most part -severe cupping is just another replacement indicator, tread depth isn't alone.

Unfortunately, there's as many reasons for cause as there are opinions on it. IMO tread squirm, loose wheel bearings, free play in the suspensions(loose/worn bushings, loose fork tube damper inside fork, etc) all cause it; and riding/braking style, suspension geometry, and tread design/compound can either minimize or exaggerate it.

Does dominant front braking exacerbate front tire cupping? Sure, but any loading causes tread distortion and squirm, and what's the alternative? Staying away from the front brake to try and minimize tire cupping? Seems to me running wide through corners or highsiding gets a lot more expensive than a new tire 2k sooner.

Keep your tires balanced and inflated properly, and your suspension in excellent condition, and you're doing everything reasonable to minimize cupping. -Anything else is a compromise of more important performance characteristics. Still getting severe cupping? Try a different tread design and compound, to find one that is more compatible with your particular operating environment. You might find that a slightly harder compound yields both acceptable mileage and performance.

Ok, thats' probably confusing and provocative enough for now...where's the synthetic vs dino oil thread...

RE: Front Tire Cupping

roadryder — Wed, 11 Jan 2012 09:52:44 GMT

I had the same cupping problem on a HD Softail. My father-in-law who previously rode the bike had used the front brake almost extensively because he thought it would save the rear brakes from their costly replacement. Not a good idea from a safety point. I believe this constant front wheel braking caused the cupping. This cupping would also cause the front end to wobble dangerously if I took both hands off the handlebars (I know, not safe, but it was just to test the front end). I replaced the tire and used the brakes normally for the next year - no more cupping (and no more wobbling).

RE: Front Tire Cupping

drummer — Tue, 10 Jan 2012 06:53:48 GMT

RePete - I want to clarify something, for me and this bike, the Metzler is the better tire. That does not mean I think it is the best tire for all riders and all bikes - far from it. I have friends that ride BMW K bikes or FJRs and they love their PR2 and Dunlops (respectively). I have read others saying that the Metzler is terrible for their ____ bike and that may be. I'm just say'n ...

Thanks for the well wishes - I too hope it proves out to be the best tire for me.

RE: Front Tire Cupping

RePete — Mon, 09 Jan 2012 17:34:13 GMT

I'm glad you like the new Metzler. If it has fewer horizontal tread lines, it should be more cup resistant. May it serve you well.

RE: Front Tire Cupping

drummer — Sun, 08 Jan 2012 16:12:30 GMT

Well I did replaced the front tire with a new Metzler Z6 and what a difference. It handles better than the PR2 ever could think of handling and I still need to break the tire in.

thanks everyone for the advice and discussions. Beastman, just joking about the "letting go of the handle bars."

RE: Front Tire Cupping

ibafran — Tue, 03 Jan 2012 12:09:47 GMT

drummer (1/2/2012)

beastman - Welcome to the forum ...

So why is it a bad thing to let go of the handle bars?

Welcome to the forum, beastman.

I noticed that line in your first post too. And I wondered the same as drummer? But, I let it go as I didn't want to appear to be contencious. Now that drummer has brought it up, my curiosity is at work again.

RE: Front Tire Cupping

drummer — Mon, 02 Jan 2012 14:55:49 GMT

beastman - Welcome to the forum ...

So why is it a bad thing to let go of the handle bars?

RE: Front Tire Cupping

beastman — Sat, 31 Dec 2011 09:11:32 GMT

I ride on 02 Kawasaki Concorse and have noticed all the front tires have cupping issues. I believe its due to riding a heavier bike aggressively into turns. I've switched to a larger, harder tire and tried various tread patterns to accomodate the weight, and the Metzeler Marathon ME880 works great, improving the durability and cupping of the tire. Running with tires that are cupped are fine as long as long as its not to bad. You will notice a slight shimmy of the front end. If the cupping gets to bad you will experience a violent shaking if you let go of the handle bars, which you shouldnt do anyways.

RE: Front Tire Cupping

OzarkHarleyGuy — Thu, 29 Dec 2011 21:46:19 GMT

Never go cheap on a helmet or tires. If you look at a tire and wonder, "hmmm should I change this tire...?" you should do it.

RE: Front Tire Cupping

RePete — Thu, 29 Dec 2011 20:15:35 GMT

Good thread. I've enjoyed all the comments so far and have learned some things. However I would not worry about uneven wear on a 8000 mile tire. At that mileage it has a right to wear in any way it chooses. It is obviously toast, as it should be. I'm glad you are mounting new tires. Enjoy them and move on.

RE: Front Tire Cupping

rnielsen — Thu, 29 Dec 2011 10:18:44 GMT

Several years ago I called Michelin's center to ask about cupping on the front of my Nighthawk 750 with a Michelin radial tire.

The person i spoke with asked if I had a new pencil handy. and since I did he said to write something down on paper and then erase it holding the pencil vertical while doing so.

"Now,look at the wear on the eraser" was his reply. It was worn ONLY around the edges, the center was not worn at all. It was suggested that's what happens when one uses the front brake, especially if you have a single disk brake. It seems radial tires "squirm" a bit with this pattern of wear being common.

I've seen this phenomenon on virtually all my bikes since, some more noticeable than others.

Ray Nielsen, in Minneapolis and still sitting out winter!

RE: Front Tire Cupping

SV-650Nut — Thu, 29 Dec 2011 08:32:25 GMT

Dunlop says...

You may not be able to entirely avoid cupping. Tire cupping or irregular wear is a somewhat common occurrence on all vehicles. On a four-wheel vehicle, you are advised to rotate your tires periodically to even out wear. Unfortunately, you do not have this luxury with a motorcycle because front and rear tires, unlike those on a four-wheel vehicle, are not interchangeable.

However, there are steps that can be taken to minimize cupping and uneven wear on a motorcycle:

Maintain your motorcycle and particularly your front forks and suspension.
Avoid hard braking whenever possible. Braking causes the tire to grab and wear in one direction. When braking is applied to the front tire, the load transfer over-flexes the tire and increases the tendency for cupping and uneven wear.
Maintain your tire pressures. Underinflation or overinflation in motorcycle tires are significant causes of cupping and uneven wear, particularly in association with hard braking and/or trailer use.

Some of today's tires feature tread patterns and constructions that are less prone to cupping than the ribbed tires of old. The Dunlop 491, D401 and D402 touring and sport touring tires are good examples.

Tire companies can, and are, helping to minimize cupping and uneven wear but you, the rider, must do your part. Follow the aforementioned guidelines. How Much Run-in Should I Give a New Tire? When new tires are fitted, they should not be subjected to maximum power or hard cornering until a reasonable run-in distance of approximately 100 miles has been achieved.

This is necessary for a number of reasons. Replacements for worn tires with different patterns and construction will not react the same. Also, a new tire is stiffer than an old tire. The new tire has a rounder tread profile, different contact patch and "lean-over edge" than the worn profile of an old tire. The new tire will also not react the same in combination with its remaining tire.

Carrying out the required run-in will allow you to become accustomed to the "feel" of the new tires and tire combinations, so you are better able to achieve optimum road grip for use in high speed, high acceleration and handling situations.

RE: Front Tire Cupping

drummer — Thu, 29 Dec 2011 08:02:28 GMT

ibafran asked the specifics about the tire so here goes. It is a Michelin PR2. It came on the bike and the previous owner said he just installed them but how many miles before that I have no idea. I put about 7000 miles on it and it could be that the previous owner put 1000. The bike is my R1200RT.
The thing is, with my strange schedule and the weather this fall, I have been one week with three rides and spans of up to three weeks without riding at all. The last couple of times I rode, corners felt very strange and the front tire "heavy." I would check the air and it was fine. I started to think it was just the hit or miss riding schedule and I was loosing my abilities far faster than ever before. Just the other day after riding and backing it into the garage is when I noticed the obvious cupping on both sides of the center line in the tire.
I am waiting for a new tire from Revzilla to show up any day now. Gonna go back to Metzlers and see if there is a handling and wear difference on this bike. My old R1100R really liked Metzlers so we will see.

RE: Front Tire Cupping

Gfurlo — Wed, 28 Dec 2011 16:19:44 GMT

Thinking about this post and different technics / break in procedures for tires. They say not to ride hard on a new tire till it's scuffed or broken in, and that should be for the first 500 and I've heard 1000 mikes. Some guys say they only get 3 to 4 thousand mile on a set of tires. So that means they are only really getting to have fun for 2 to 3 thousand miles.

I remember once a post about front tires wearing more on the right hand side then the left. The following weekend I went by a cycle shop and went through a bunch of the used tires and I was amazed that you could tell front tires from rear and the right hand side from the left with little effort. The fronts were/had more cupping, and were worn across the entire tread area. Rears were more worn in the middle with good tread on the sides and yes the front tires were more worn on the right side then the left.

RE: Front Tire Cupping

ibafran — Wed, 28 Dec 2011 15:18:43 GMT

Dedsled's post is the one that I heard long ago regarding rotation direction. At the speeds that I run, this has little risk for me. Water dissipation is another matter. I don't believe that I run hard enough in the wet to worry about tire rotation direction.

A lot of those ironbutt rally riders put a lot of freeway miles on their tires and get cupping with very little brake use? The causes of cupping are pretty much a mystery to me. And I have yet to figure out a good way to test cupping for myself. I hate to rely on a rumor or supposition for the explanation.

I don't like cupping any more than the next rider. But, traction and safety wise it hasn't been that big of a concern to me. But it does make the steering heavy requiring more effort to pitch the bike into a lean and keep it there. As I reported in an earlier thread on tires, a badly worn and cupped tire will make my bike slow to turn in and require so much more effort that a new tire will feel 'darty' by comparison until I get used to it. On a fresh tire, the bike was so much more responsive that I early apexed a right hander and put myself on the side walk expecting the bike to corner so slow that I would remain on the street on my desired line.

RE: Front Tire Cupping

dedsled — Wed, 28 Dec 2011 05:00:34 GMT

I don't know if this is true or not, but a very experienced dealer told me once that the directional arrows on motorcycle tires are there because of the way the tires are built. The tread is "laid on" the tire in a certain direction and where the two ends of the tread meet, one end is "laid over" the top of the other end (overlaps.) If the tire is mounted in the wrong direction, there is a greater chance of the tread "seam" coming apart and the tread separating from the carcass. The chance of this happening at speed is enough to keep me from mounting a tire in the wrong direction.

RE: Front Tire Cupping

trauscher1 — Tue, 27 Dec 2011 20:33:37 GMT

drummer;
Interesting question. Obviously, the tire wasn't perfectly good one day and then cupped the next. It gradually got that way--and if the handling changed--it changed gradually. If it gets worse, as it probably will, it will do so gradually. Some years back, uh, nearly 40 years back, I mentioned the cupping I was getting on my Z1 front tire. The dealer told me that they almost never saw cupped front tires until disc brakes began to be installed on the bikes. Apparently among the many things that could cause cupping, one of them is how heavily the front brake is used. I try to use the brakes lightly and usually do not experience cupping--if I get some, it is usually after more than 20K miles or so. Watch yer air pressure!

RE: Front Tire Cupping

Gfurlo — Tue, 27 Dec 2011 19:46:39 GMT

[quote]ibafran (12/27/2011)

[quote]
Once, I dismounted a cupped tire and turned it around for a re-mount as an experiment in getting it to erode the other way and getting some useful 'feel' back into it. I didn't like the way it 'felt' and had no confidence in the tire. The traction might have been very good but I just couldn't tell and wasn't up to the risk to learn anything more. If I was going to flip a front again,[/quote]

Don't most motorcycle tires have direction arrows that mean "to mount so rotation is in the direction of the arrow"?
I wonder if that is just for water dissipation or other reasons.

RE: Front Tire Cupping

ibafran — Tue, 27 Dec 2011 14:56:10 GMT

drummer (12/26/2011)

So I have three to four days of possible riding before I can get my front tire replaced. The existing tire is cupping but no wear bars are showing. Is it safe to ride the bike as long as i don't push the turning to hard? What about highway riding, does that present any problems with a cupped front tire? Just curious if you think I should ride or not.

As long as no wear bars are near the surface, I would ride the tire. Wish I knew which tire/model and what bike? And I would ride the tire like normal on the hwy. Local streets with sand/slime in the corners, I would go a little slower than normal.

My dunlops cupped to a point where I didn't like the feel of traction they were giving and I changed them out a little early. I had a bridgestone (BT010) that cupped about half way thru expected life that I changed out because I couldn't stand the vibes and the slight 'pushing' that it was giving me. My continentals cupped but it didn't seem to matter. I have a Dunlop now that doesn't seem to cup but I can get it to push more than I like. I don't mind taking a rear down to the cord. But a front really seems to go bad before it goes bald or cord shows and it has to be changed.

I would like to render an opinion about why harley fronts do not cup and seem to last a long time. But it would just PO the harley crowd. And we would gain no real knowledge.

I now look at front tire tread patterns and try to guess what will be most likely to cup and how soon. While I have had a bunch of cupped tires, I have never felt they were 'unsafe' to ride on. But I do slow down to finish off the tread life when they start pushing a lot.

Once, I dismounted a cupped tire and turned it around for a re-mount as an experiment in getting it to erode the other way and getting some useful 'feel' back into it. I didn't like the way it 'felt' and had no confidence in the tire. The traction might have been very good but I just couldn't tell and wasn't up to the risk to learn anything more. If I was going to flip a front again, I would try it as the a 12k mile tire reached 6k miles before any cupping might get noticably bad.

Note to all: I will be glad to experiment with tires and make the best report that I can if anyone wants to supply me with tires that fit an 05 Sprint.

RE: Front Tire Cupping

jerseyjim — Tue, 27 Dec 2011 11:26:17 GMT

Cupping could be anything in the front end...from balance to fork oil, to a slightly dragging rotor...I've even heard that sometimes it's caused by the "crown" in the middle of the lane...where the car tire don't ride...we ride in the kind a natural depression. Who knows?

All 4 of my UJMs had this problem. But I had to change tires every 10 thou or so....and I only noticed the cupping around 8...it didn't bother me. But if it bothers you....get a new tire.

Funny...with both my Harley dressers...no cupping or feathering of any kind. And these front tires last for around 30 thou.

Just thought I'd throw that in there.....

RE: Front Tire Cupping

dedsled — Tue, 27 Dec 2011 07:36:22 GMT

Good question. As for me, I would be just as concerned with why the tire is cupping. If something is amiss with the front end, could that be more dangerous than riding on a cupped tire?

RE: Front Tire Cupping

sgtslag — Tue, 27 Dec 2011 06:12:39 GMT

Your best option is to consult a professional whom you trust. Granted, they may be gunning for a sale, but you can at least try, and don't be afraid to ask them to explain the reasons behind their recommendation, if they propose replacing it immediately. Be tactful, but also be assertive. You can always get a 2nd professional's opinion, as well. Building a trusting rapport with a local mechanic is very advantageous, in the long run. It takes work, and a bit of trust, on both sides. Cheers!

RE: Front Tire Cupping

Gfurlo — Mon, 26 Dec 2011 23:22:05 GMT

What one person thinks it bad is like, the decision with my wife about what temperature the themostate should be set at.

My suggestion is, If you are uncomfortable riding on the tire, don't.

Front Tire Cupping

drummer — Mon, 26 Dec 2011 13:49:49 GMT