[mudman]

I had recently changed my rear tire after a 7,000 mile cross country tour with friends from the East coast to the West coast and back. The tire had 8,039 miles prior to my departure and looked in great shape. During the ride out we had noticed the rear tire starting to cup. The next morning with cold tires I checked the pressure and found it to be at the recommend pressure of 48 PSI. Concerned about the cupping I kept a close watch on the tire and pressure. On the way back about 1500 miles from home I noticed a roughness in the bike when coming to a stop. Inspection again revealed the cupping getting worst. Prior to my last fuel stop arriving home the cupping was severe. With 200 miles to go and a little care I figured I could make it safely home. I am very religious about my tire pressures and use an Accugauge tire gauge to insure accurate pressures. This was my first Bridgestone after running two sets of Metzler’s on the LT with no problems. By the time I arrived home it was very prevalent that something was seriously wrong. After removing the tire I decided to section the tire. Examination of the tire revealed the tire had separated on both sides of center. On the swing-arm side it started rubbing the swing-arm to the point it left a .040 thousands wear notch. This happened sometime during the last 200 miles of the trip. In the images of the tire cross-section you can see the severity of the separations. Separation was found in all seven sections of the tire. Also notice the one hundred sixty thousands clearance between the swing arm and a newly install Metzler. This is a little closer than I expected for swing-arm to tire clearance.

Because it is only a sample of one of this tire and I do not know the makings of the Bridgestone motorcycle tires, I can not conclude a definitive failure analysis. But I do know the history of the tire and compared to the Metzler’s I have run on this bike in the past this has never happened. As a failure analysis technician at Lockheed Martin my knowledge and background tells me this tire was defective from the beginning and perpetuated over time. My thinking is, if a tire is kept to proper inflation and not abused/overloaded you should be able to run a tire to the cords without having this type of failure. After arriving home I compared the Accugauge tire pressure gauge to another gauge to find it was reading were correct. I consider myself lucky the tire did not totally fail riding two up at highway speeds pulling a trailer.


Is this the famous Firestone separation failure problem?

Below is the history of the tire.

Tire: Bridgestone BT020R 160/70R-17

Motorcycle: 2001 BMW K1200LT

Installed date and mileage: October 2, 12003 @ 20,008 miles

Removed date and mileage: September 26, 2005 @ 35,022 miles

Total mileage: 15,014

Tired pressure: 48 PSI cold

Ride loads: One up 10%, Two up 40%, Two up with Un-igo 35%, One up with Un-igo 15%

Rider/SO weight: 159Lbs. / 140Lbs.

Trailer: Uni-go


Links:

Bridgestone BT020R 160/70R-17 tire failure web page.

http://pulsefl.0catch.com/bt020r/


Word document:

http://pulsefl.0catch.com/bt020r/Bridgestone_tire_failure.doc


Individual images links:

http://pulsefl.0catch.com/bt020r/tire-1.jpg

http://pulsefl.0catch.com/bt020r/tire-2.jpg

http://pulsefl.0catch.com/bt020r/tire-3.jpg

http://pulsefl.0catch.com/bt020r/sections.jpg

http://pulsefl.0catch.com/bt020r/section_a-1.jpg

http://pulsefl.0catch.com/bt020r/section_a-2.jpg

http://pulsefl.0catch.com/bt020r/section_a-3.jpg

http://pulsefl.0catch.com/bt020r/section_b-1.jpg

http://pulsefl.0catch.com/bt020r/section_b-2.jpg

http://pulsefl.0catch.com/bt020r/section_b-3.jpg

http://pulsefl.0catch.com/bt020r/section_c-1.jpg

http://pulsefl.0catch.com/bt020r/swingarm-1.jpg

http://pulsefl.0catch.com/bt020r/swingarm-2.jpg

http://pulsefl.0catch.com/bt020r/swingarm-3.jpg

http://pulsefl.0catch.com/bt020r/swingarm-4.jpg

http://pulsefl.0catch.com/bt020r/new_install.jpg

 

[Malki]

Personally, I'd never run any make of tyre on a bike this size/weight to 15000 miles, it would be long gone into the bin. I don't scrimp on tyres, simply because they are the lifeline. 3/4 worn and i'm severely worried and bin them. I'm used to running BT020's on my Ex-FJR, mostly motorway use in Europe at speeds up to 155mph or the twisties in the mountains. My own experience shows that the tyre may wear slowly and impressivley til it reaches -50% of wear then it reaches the softer compound rubber, which in turn wears at an alarming rate, especially if used in a straight line for thousands of miles.
It may well be a fault in your tyre, but I suggest it's just plain worn out.

Malki

 

[Wolfgang]

Bridgestone

I could not agree with you more!

I have had two rear Bridgestone fail in a way that seems to be identically to yours.
I made phone and e-mail contact with Bridgestone and got brushed off.
I have switched to Avon for now since I consider Bridgestone and Metzler unsafe, but for very different reasons. Metzlers are dangerous in wet weather. Bridgestone become seperated and I believe it is just a matter of time until someone gets hurt because of it.

Maybe with your background you can get Bridgestone Firestone to respond.


Thanks for your efforts!

Wolfgang

 

[strsout]

Hi Don
I understood that you came from Metz to BT020. Well... welcome to the grip with low mileage...
my BT020 last about 8 to 9K miles on the front and 9 to 11K on the rear.
Yours you manage to get over 15.000... I would say you were luck that nothing fail during your trip. Actually, even when I was using Metz (only for to sets, on the first 1999 bike), I got about 14K on that.

I would say nothing is wrong with your tires. They just last over life then they were suppose to.

Just to give you a felling: I don't ride aggressively, I always check the tire pressure (42/48), I don't speed (65/80) and I don't scraped pegs on turns. So I would say I'm a pretty conservative rider, this is why I can go 9K miles on BT020. Some riders here you will see they barely get 6K on those tires. They have a lot of grip, but lack of mileage.

 

[mudman]

I have to agree the tire is well worn and I would have replaced it sooner if I had not been in travel, but it should have never separated as I found. As you can see in the images there is still significant tread left on the tire. If all my automotive tires did this I would be very weary of the manufacture and safety of the tire. Of all the years I have never been riding I have never had a motorcycle tire fail like this. I posted this to give the motorcycle rider community better insight of the things we may take for granted. For one, I will now be even more conscious of the tires I run on the K1200LT. I went back to Metzler's because of the past history I have had with their product.



Thanks for the reply Guys.

 

[JATownsend]

Another BT020 Failure...

Great writeup Don.

There seems to be a trend here and its rather disturbing. I also had a Bridgestone BT020 fail recently, while coming home from CCR.

I have yet to hear back from the dealer and the tire rep. Mine also bulged and was rubbing the swingarm and inside the separation was very evident.

It was replaced at Sturgis BMW and they were rather shocked. They shipped it home for me to take to my local dealer.

Luckily, it happened close to a town in the Badlands. The tire had less than 7000 miles on it. 3500 one-up and fast. And, about 3000 two-up with trailer. Pressures at 42/48-50.

I really like the BT020 radial handling and wet grip, but I will never take my wife on a long, hot trip again with Bridgestones on the bike.

Wearing out is one thing, they should NOT fail. And we are hearing more stories all the time.

 

[meese]

Yep, this is exactly what we've seen before. I had a BT020 separate in Germany, which caused a big bubble that rubbed the swing arm. Others have reported this as well. Few of us did as much investigation as you, and several have gotten Bridgestone to replace the tire or give partial credit.

Note that we have also seen a few ME880 failures, but far less than with the BT020. I had an ME880 develop cracks in the tread grooves, such that I felt it was unsafe to ride on. Metzeler refused to cover that tire at all, and so I paid top dollar to have it replaced while on the road.

I must also say that I've never gotten 15K out of a rear tire of any brand. Well under 10K is more likely. That has partially to do with our rough SoCal freeways, and my admitted heavy throttle hand and aggressive riding style. Still, your tire did show a fair amount of tread left, and the tire should be able to last down to the wear bars at least.

One minor thought, could cutting the tire into sections have contributed to the separation seen at every section? I don't wish to discount your problem, but I'm seem to remember past failures occurring in specific places, rather than around the whole tire.

So I feel this is similar to the rear drive case. That is, the part is marginally insufficient for use on the LT, there are enough confirmed failures to prove that there is a problem (to us and the manufacturer), and the manufacturer is not publicly accepting any responsibility, but is dealing with each failure on an individual basis.

Personally, I hate the way the ME880's feel on the LT and won't run them unless I'm stuck on the road and have no other choice. The Bias BT020 tires seem to be a compromise, with better handling than the ME880 but not as sharp as the BT020 Radials. The Radials easily handle the best, wet or dry, and I've run through four of them with no problems.

That means each of us is left with the same choice. Decide whether the possibility of a failure (rear drive or tire) is sufficient enough to stop using the product (LT or BT020), and then boycott that particular manufacturer (BMW or Bridgestone). I'm still riding my LT with BT020 tires, but I know what to look out for, and I check the rear drive and tires frequently.

 

[strsout]

Don,
I hope you in any way taught I was putting down your post (sorry... English as a second language sometimes I lack some specific better words).
Actually, that was one of the good ones. Shows all the details on your problem in a very professional way with a lot of pictures to make us understand.
No. it's not that I'm doing it.
What I try to tell you is that on this bike, maybe (note: maybe) because the specific of it, it's hard to have a good tire so we need to compromise on it.
There is Avon I never used, but between Metz and BT020, I prefer BT020 even do I got only -10K on each set.
Only once I used more than 12K and my rear tire was start doing exactly what your did: reaching the swing arm.
I've been used so far 2 sets of Metz and 7 sets of BT020 and never had any problems with BT020 but I belive that if you try to use those over 10K that separation will occur. I read so many post telling it.
But on your side I would say that you tire has a lot of thread on it. Looks better than many of my sets that I changed with much less miles.
Thank you

 

[jayz9705]

Avrill, I find it interesting that last August, on the last Sunday of the "week of madness", Sturgis BMW had another LT in the shop, with the same tire problem, for 4 days while my replacement tire got lost in shipping.
I find it very interesting that the dealership was shocked at the situation!

BTW, it was the 2nd of 3 times that I had an 020 fail via separation. I now have Avons on the bike and they seem to be doing well, for now, with @ 5K on them.
Time will tell.

 

[SLICK02]

I have most of my ride time on Harley Davidson big twin, and have grown to trust the Metzlers in the hot the cold the wet and the dry, have been running them exclusively for 3 years and that's what I run on my K1200, I only get about 8-9 k out of them on the HD, but I have never felt compromised in any way by the tire, I did try a set of Avon's on a sportster I built for my wife but only put 4700 miles on them before trading up, so I really can't say one way or the other on their behalf, but I do ride with peace of mind on Metzlers.

SLICK

 

[wilbar00c]

Averill, sorry to hear about your going home "tire failure". From reading all the BT020 ply separation reports over the years, on this site. It seems to me that this radial tire is flex cycle limited (mileage limited) at the tire temperatures, speed, and loads that the LT subjects it to. The manufacturing process that bonds the plys together must leave no room for error, if quality control is not right on, plys separate. The inner wall becomes porous and lets air in between the plys, and the bubble forms. Heat is a tires worst enemy and our LT's rear tire runs hot to the touch, mostly from the drive line heat conducted from the engine. Maybe someone has measured the tire temperature with a pyrometer, after a hot day fast run, and could comment on how it relates to the manufactures temperature operation envelope (if the envelope is available to us users). Ply separations were not that uncommon in the 60's when the US tire manufactures switched from bias ply to radial. Barnett

 

[meese]

First, I don't think you can really compare tire brands on different bikes. The manufacturers will build the tires differently in each size, to optimize them for the bikes they're intended to fit. So how a particular tire handles or lasts on an HD may not match how it will handle or last on an LT. Gross comparisons are probably OK, (ME880 harder for more mileage, BT020 softer for more grip), but details and how long a tire actually lasts are very specific to the bike and each rider.

As for tire temps, I agree that the LT's rear tire can get pretty hot during normal operation. There's just a lot of weight to deal with. Add a passenger and luggage and maybe desert air temperatures, and the problem only gets worse. Still, the tire manufacturers should know all that, and build the tire accordingly.

Here is an excerpt from a post I made on the old site:

I installed a SmarTire system just before CCR, with a new pair of BT020 bias tires. I don't have a lot of data to work with yet, but I did find out the temp alarm goes off at 187 degrees, which is fairly easy to reach in 107 degree air temps at 90 m.p.h. It did reach 199 degrees at one point as well. (rear tire)

One the way back, air temps stayed closer to 90 degrees, but I still hit the 187 warning mark a couple of times.

No real conclusions, just adding some data to work with.

 

[mudman]

Hey Guy's,
Thanks for the input.

Elton no offense taken at all. With the reply’s I have received, I am very surprised of the amount occurrences with this tire. It just may come down to this tire is just marginal for handing the loads, temperature and speed of the LT. I emailed the failure report to the Bridgestone Motorcycle Division yesterday. Hopefully I will get a response.

Ken,
I cross-sectioned the tire with a band saw using a medium tooth blade parallel to the separations. This would have little no effect on the tire separations as you see in the images. If I had a very dull saw blade or in correct blade speed this could affect the cut cross-sections. Care and thought is taken not to obscure or damage the point of interest. Unless I needed a highly polished cross-section this would affect the analysis. The sample would have to be mounted, ground polished beyond the cut face.
That was great information on tire temperature you posted. Just a few less PSI could drastically affect the tire temperature.

I still say, if a tire is kept to proper inflation and not abused/overloaded and run within the manufacture limits you should be able to run a tire to the cords without having this type of failure.
Again thanks for the reply’s and keep a close watch on your tires.

 

[beemer666]

Possible reason

I use BT020 on all my bikes with no problems. I have noticed lots of people on this site run the rear BT020 at 46 psi on the LT, but the recomended pressure is 42psi, it's 46 psi for the old G702.

Might by worth checking with Bridgestone in your country.

 

[JATownsend]

Sorry...your info is incorrect.

I use BT020 on all my bikes with no problems. I have noticed lots of people on this site run the rear BT020 at 46 psi on the LT, but the recomended pressure is 42psi, it's 46 psi for the old G702.

Might by worth checking with Bridgestone in your country.

Actually, here is the BT020 product info line directly from the Bridgestone site:

099635 160/70R17 17 BT020R BW TL M 79V V 25.9 6.1 8 (4.50)4.25-5.00 963 48 K1200LT 1999-2003

I've taken the liberty of bolding the PSI number in the second to last column.

I don't believe anyone on this side of the pond would be running 42 on a loaded KLT. Except perhaps on track-day at the expense of tire life.

 

[mudman]

I have not received a response from Bridgestone since I emailed the results of my tire failure. I do not feel this is a rare occurrence so I am going to contact the National Transportation Safety Board with my findings to get this failure on record. This just might help someone out if this failure unfortunately happens to kill or injury someone. I’ll keep you posted.

 

[Deanspinner]

I have a 2005 k1200LT currently showing 11500 miles. It still has the original Bridgestone BT020 tires on. My tires are not radials, and I am wondering if the failures are just on radial tires? The back tire has never given me any cause for concern, but the front tire developed cupping around 6000 miles. This caused wobbling under limited conatact with the handlebars, but as long as I kept at least one hand on the bars it did not escalate. My next set of tires are going to be metzlers, but I love the grip of the BT020.

 

[meese]

I haven't seen any reports of the BT020 Bias tires separating, but they're a lot newer (less miles run on fewer bikes). It's possible that the separation is one of the reasons Bridgestone developed this particular tire, but without some inside information we can't really know for sure.

 

[Jim_Schuyler]

Doh?

I have a 2005 k1200LT currently showing 11500 miles. It still has the original Bridgestone BT020 tires on. My tires are not radials, and I am wondering if the failures are just on radial tires? The back tire has never given me any cause for concern, but the front tire developed cupping around 6000 miles. This caused wobbling under limited conatact with the handlebars, but as long as I kept at least one hand on the bars it did not escalate. My next set of tires are going to be metzlers, but I love the grip of the BT020.

You guys are slow to catch on. You think Bridgstone just quite putting these radials on the 05 because they don't want to make money? The bike is too big for them!!! Back to 880s next time. No problem with the 7,500 miles on the bias Bridgestone yet.

 

[lad]

Another BT020 Failure

Last week, while doing an adventure ride on my LT, my rear BT020 gave up on me. Luckily, I was on a back country road, being followed by p/u truck of company employees.

I had just finished riding a back country gravel road for 20 miles, so I attributed the failure to the 'dirt' riding. Couldn't find any punctures, but the tire had lost air. Got the tire re-inflated (man, those CO2 cartridges don't fill a rear tire very full. The CO2 got the tire aired enough to ride 2 miles to a service station with a compressor. Once I got the tire aired, I rode in to OK City (~60 miles), where the good folks at the OK City BMW shop, got me in and re-treaded with some fresh 880's.

I had checked inflation before I left for the trip, and had pressure monitors on the stems, which I checked every morning before riding. The tires had developed a wobble, and I could absolutely not turn loose of the handlebars, without going into an out of control wobble.

The front tire had about 6000 miles. The rear had half that. They were the radials. The front had cupped pretty badly. The rear looked new, except in the highway section, which looked like 50% wear. I had ridden the bike 100% solo, and load when traveling was probably only about 50 lbs (clothing, computer and brief case). I weight about 225 lbs.

I did not notice bulges, and did not notice any damage on my swing arm. I figured that I had damaged the tire during the rough riding, and discounted the wobble as due to the tread wear. I wish that I had read this thread before my trip.

I went back to 880's, because of the BT020 wobble, and the poor tread life. I got 17000 miles out of my 1st front 880, and 8500 out of the rear. Only concern with the 880s is wet traction. Definitely put pucker prints on the seat during wet rides.