BT023GT front cupping

[Fred W]

How does one determine the correct tire pressure? With 39/40 psi, after a good warmup, my front tire pressure is 44 psi: a 10% increase. This is what I understand is optimum.

Technically, the best way to do it is with tread temperature. The 10% rise in pressure is an indirect indication of the temperature rise. But I bet if you started with 42psi you'd still see ~ 10% rise, and maybe the tread wouldn't wear quite as unevenly. This is a pretty good article on running various pressures on the track and on the street.

 

[AVGeek]

I put on my 023 GTs back in November, then proceeded to scrub them in during the two rainiest days I have yet seen here in AZ. I run 40psi front, and am diligent about checking pressure weekly. I previously ran Metzelers and they cupped horribly, which is what got me checking pressures weekly.

 

[Spud]

I have to strongly disagree with the the topic description that says the 023GT is as "bad a tire as the stock 021". The 021 front is a POS on the FJR for sure. The 023GT is completely different. It will outlast the rear, keeps its round profile through the wear, and handles the big weight of our bike very well.

I'm on my 3rd set of 023GT's because I like the price and handling. To compare front/rear wear, here's the rear on my last set when I replaced them:

Here's the front off the same set (6800 miles--a record for me...)

 

[SkooterG]

Here's the front off the same set (6800 miles--a record for me...)

First of all, you be crazier than me ( and that's saying something) to get metal belts like you did!

Your front looks good. Why replace it? Photo is not as close as I would like, but I see no cupping. You should see my front. But then I do have 11,000 on it. Not sure when I first noticed it. Still don't feel it and can lean high angles with confidence so I am not complaining too much.

 

[Falko]

I didn't mean it to say the 23 is as bad as the 21, I meant the cupping is as bad as it was on the 21, but looking at it now I absolutely get your point. I'll see if I can change it. The 23 feels a lot better than the 21 which was very washy feeling, not sure if that was due to the weaker carcass or what.

I upped my pressure to 42 in the front this morning, see if that helps. It didn't seem to affect the turn in or ride, and hopefully won't affect the grip.

Again, thanks all for the responses.

 

[Slardy]

How does one determine the correct tire pressure? With 39/40 psi, after a good warmup, my front tire pressure is 44 psi: a 10% increase. This is what I understand is optimum.

Technically, the best way to do it is with tread temperature. The 10% rise in pressure is an indirect indication of the temperature rise. But I bet if you started with 42psi you'd still see ~ 10% rise, and maybe the tread wouldn't wear quite as unevenly. This is a pretty good article on running various pressures on the track and on the street.

Fred, my reference to a 4 psi increase from cold to hot derived from that tech article that you linked to in your post.

I will make a run with 42/42 psi and see how the increase compares to 39/39.

One of the big differences that I experienced in the tire switch is the when running the PR2s at 42/42, my FJR, over most of the tire tread life, required considerable handlebar input during technical riding (getting higher with tire wear). The 023GTs require negligible handlebar input: the difference is significant. And I would not expect that to change with additional wear because the tire is maintaining its shape.

I have never experienced straight line instability with any tire that I have run on the FJR. I currently have 47K miles on my 2007.

 

[Spud]

Here's the front off the same set (6800 miles--a record for me...)

First of all, you be crazier than me ( and that's saying something) to get metal belts like you did!

Your front looks good. Why replace it? Photo is not as close as I would like, but I see no cupping. You should see my front. But then I do have 11,000 on it. Not sure when I first noticed it. Still don't feel it and can lean high angles with confidence so I am not complaining too much.

I like to put on new tires in sets, and keep the old ones around for lost Canadians. Sure enough, last summer at WTF.0 some Canadian showed up to Idaho Falls with a bald front tire, and that tire in the photo was donated.

 

[RPrice]

Here's the front off the same set (6800 miles--a record for me...)

First of all, you be crazier than me ( and that's saying something) to get metal belts like you did!

Your front looks good. Why replace it? Photo is not as close as I would like, but I see no cupping. You should see my front. But then I do have 11,000 on it. Not sure when I first noticed it. Still don't feel it and can lean high angles with confidence so I am not complaining too much.

I like to put on new tires in sets, and keep the old ones around for lost Canadians. Sure enough, last summer at WTF.0 some Canadian showed up to Idaho Falls with a bald front tire, and that tire in the photo was donated.

I've got an 023 front that doesn't look quite that good up here in Salmon, ID, but still has some miles left. If you hear of a stranded Canadian that needs another one, they can shoot me a message.

 

[SilveradoSlick]

I've been running 42 in front with no cupping on the 023GTs.

On my second set of 023GTs, at 6700 miles the wear is so even that other than the scuffed edges and thin tread, they look great. Road feel and tip in is still excellent, no front cupping or funky handling...basically I'm very happy with them. For comparison I'm running 41/42 for one-up, two-up, loaded or empty. Rear tire does have some trailing edge feathering, mostly due to me. This set looks to be good for another 1500 +/- miles. I can post pics tomorrow if anyone's interested.

I'm on my second set of 23s non GT. They have shown all the normal signs of fucked tire wear but have handled really good right up to 10k (I mean really good) I went with the non GT because a friend advised that the GTs were hard to mount. Wanted a tire that isn't harsh.

Don't know where your friend got his information, but the 023GTs are as easy to mount as PR2/3s, even *B* spec. IMO, the GT ride is better than Michelin new and a huge improvement at end of life. Try'em!

--G

I gave up on mounting the GTs and paid somebody to do it. They're cheap enough to almost cover the cost and I don't have to do it. The ride's not harsh at all and grip and mileage are great.

 

[snackbauer]

I use a Cycle Hill changer, and didn't find the BT023 GT's any more difficult than PR2's.

 

[ekms377]

The GT was harder to mount as it holds it shape and tries to bead before you can get it on the rim. Put it out in the sun before you try and mount it. That helps and so does a second set of hands. :assassin:

 

[escapefjrtist]

<snip> Put it out in the sun before you try and mount it. That helps and so does a second set of hands. :assassin:

Sun or a buddy definitely helps, but these XtraHand Clamp work when mounting solo! Add the Yellow Thing and it's a one man operation.

--G

 

[Tree Doc]

<snip> Put it out in the sun before you try and mount it. That helps and so does a second set of hands. :assassin:

Sun or a buddy definitely helps, but these XtraHand Clamp work when mounting solo! Add the Yellow Thing and it's a one man operation.

--G

That Yellow Thing is the shizzle! I just put my first set of 023GT's on my FJR last week. I've been mounting the PR2's on the FJR as well as others for friends, using my Harbor Freight unit and Parnes balancer. I COULD NOT get the 023GT on the rim and I fussed it with for a long time. Ended up taking it to my buddy's shop where he has pro equipment and even he had to put the muscle into it but he's got a Yellow Thing and what a lifesaver that is!

 

[Fly Bye]

Thanks, all. Sounds like I'll cram a few more molecules of air in them and see if that helps. I went to the GT's as I thought they were more designed for the heavier bikes. Maybe I need a new tire gauge.

I just completed a 2,032 mile trip to Southern California and back. I had just installed front and rear 023GT's with about 300 local miles on them prior to leaving on this trip. I inflated both front and rear to 41 lbs (cold). At this point both tires look great. I have no comlaints about these tires at this point.

Your comment about a new tire gauge is not without merit, they do vary. I don't know what the exact fix is for that other than don't buy a cheap one.

 

[Falko]

Yeah, I have two gauges and they are accurate to each other within my eye sight's abilities. I've run about 400 miles since I noticed this, I haven't seen any difference in wear, no smoothing, but more importantly, no worse.

 

[SYB Rider]

I have the 023GT both front and back. I run lower pressure in the front 32 psi when solo and 36 when 2 up. The front shows no sign of cupping after 5000 km. The rear on the other hand is a basket case. The rear edge is raised significantly. I attribute that to suspension settings i.e. rebound. It is so far gone that no adjustments will bring it back. On the other hand, the shock is stock and may just need to be changed out for an Ohlins!

 

[wmadoty]

Falko,

I have no cupping and almost perfect wear on my BT-023s after 2700 miles. Here are photos of my front. After my last ride I was thinking that this is the best wear tire pattern that I have had on my FJR for years I was unhappy with my Michelin Road Pilot 2s because of harsh ride and typical dual-compound trapezoidal wear pattern up front. And higher price, too.

Don't know what the mileage will be, but it looks like ~6K, same as the Road Pilot 2s that I have used.

edit: I forgot to mention that unlike the 42/42 that I have been running in the PR2s, I have been running 39/39 psi on the 23s.

FRONT #1

FRONT #2

I see cupping in both of those pictures. Looks like normal heavy motorcycle front tire cupping to me. I doubt it has an effect on handling, but it is there and it will only get worse.

 

[Neil San Diego]

Just for grins and comparisons, here is a BT021 front (OEM) at 4500 miles. It started this at about 2000 and the handling went to hell in a bucket. The 021s really are a POS...

Back to PR2s and everything is good again.

 

[phroenips]

I have the 023GT both front and back. I run lower pressure in the front 32 psi when solo and 36 when 2 up. The front shows no sign of cupping after 5000 km. The rear on the other hand is a basket case. The rear edge is raised significantly. I attribute that to suspension settings i.e. rebound. It is so far gone that no adjustments will bring it back. On the other hand, the shock is stock and may just need to be changed out for an Ohlins!

Obviously, do whatever works for you, but those pressures are REALLY low compared to what most everyone else on the forum runs. Personally, I run 42 front and rear, some people take it down to 40 in the front with 42 in the rear, etc.

 

[Jim in Phoenix]

I had a set of 023GTs on my FJR for 11,000 miles before I changed them out for a set of PR2s. One thing I rarely see addressed in these tire mileage discussions is suspension. In my case, I ordered an upgraded suspension and had the suspension adjusted for my weight and riding style by a mechanic who works with an AMA Pro Racer. I definitely know that a bad suspension on a car will drastically impact tire performance and mileage. Isn't it likely that the same thing could happen on a motorcycle? I have watched Skooter's taillights disappear as we headed into the mountains and if he gets over 11,000 miles from a set of tires, I have a hard time believing anyone should get less miles per tire. Just my .02 - YMMV