Bridgestone BT45 Bias-Ply 150/70 rear tire

[Red Mist_imp]

This thread was initially posted to talk about how much I like the BT45's with the 150/70 rear. I still do, but there was a concern I had regarding tire clearance.

This seems to be resolved and I can't determine that there is any lack of clearance. Marks on the tire were apparently from some other cause.

The combination works very well, I like the handling better with the beefier rear tire with more available sidewall. Overall gearing also goes up a little, so your fuel mileage will improve a little over the stock tire. Acceleration doesn't seem to be affected noticeably.

As with anything, departure from stock can cause anomalies. The rest of this thread explains the situation.

YMMV

 

[Ack-CB11_imp]

Great info, Thanks

 

[flynrider]

I'm on my 3rd set of BT-45s on my CB750 (which specifies bias tires). I think they are an excellent "all around" tire. There are stickier tires, but I've never had an issue scraping pegs on the 750. They also wear quite well.

My CB1100 came with the BT-54s from the factory. I had heard from sources that they would be available in the U.S. in early 2014. I see by a quick look on the web that they seem to be generally available in Europe and the U.K., but not in the U.S. :huh:

The BT-54 seems to be Bridgestone's radial equivalent of the BT-45. I've been satisfied with the performance of the BT-54s so far (just over 3K miles). I'm hoping that they'll be more widely available by the time I need a new set of tires for the CB11. If not, it's nice to know that the BT-45s will work.

 

[AzBob_imp]

This thread was initially posted to talk about how much I like the BT45's with the 150/70 rear. I still do, but there was a concern I had regarding tire clearance.

This seems to be resolved and I can't determine that there is any lack of clearance. Marks on the tire were apparently from some other cause.

The combination works very well, I like the handling better with the beefier rear tire with more available sidewall. Overall gearing also goes up a little, so your fuel mileage will improve a little over the stock tire. Acceleration doesn't seem to be affected noticeably.

As with anything, departure from stock can cause anomalies. The rest of this thread explains the situation.

YMMV

I have the Bridgestones from the factory with almost exactly the same miles. I don't see any weirdness with the tires; I'm not sure what you mean by cupping? Were your tires under-inflated by any chance? The recommended pressure is quite high (42 psi if memory serves).

Quote:, and the rear was not quite wide enough to match the lean angle available from the front.
That's the way every motorcycle I've ever seen is. As long as the rear tire is wider, the front will not come close to it's maximum lean angle. It's just not physically possible. The difference on my CBR is almost comical. Quite frankly, I don't want the front tire anywhere near its limit. The rear can loose a bit of traction and its recoverable. The front, not so much.

 

[Red Mist_imp]

BT54's are readily available stateside; check out http://motorcycle.chaparral-racing.com/search?w=bt54, among others. Prices are quite good, too. You're just limited to the stock sizes.

This thread was initially posted to talk about how much I like the BT45's with the 150/70 rear. I still do, but there was a concern I had regarding tire clearance.

This seems to be resolved and I can't determine that there is any lack of clearance. Marks on the tire were apparently from some other cause.

The combination works very well, I like the handling better with the beefier rear tire with more available sidewall. Overall gearing also goes up a little, so your fuel mileage will improve a little over the stock tire. Acceleration doesn't seem to be affected noticeably.

As with anything, departure from stock can cause anomalies. The rest of this thread explains the situation.

YMMV

I have the Bridgestones from the factory with almost exactly the same miles. I don't see any weirdness with the tires; I'm not sure what you mean by cupping? Were your tires under-inflated by any chance? The recommended pressure is quite high (42 psi if memory serves).

Quote:, and the rear was not quite wide enough to match the lean angle available from the front.
That's the way every motorcycle I've ever seen is. As long as the rear tire is wider, the front will not come close to it's maximum lean angle. It's just not physically possible. The difference on my CBR is almost comical. Quite frankly, I don't want the front tire anywhere near its limit. The rear can loose a bit of traction and its recoverable. The front, not so much.

I have the Bridgestones from the factory with almost exactly the same miles. I don't see any weirdness with the tires; I'm not sure what you mean by cupping? Were your tires under-inflated by any chance? The recommended pressure is quite high (42 psi if memory serves).

Quote:, and the rear was not quite wide enough to match the lean angle available from the front.
That's the way every motorcycle I've ever seen is. As long as the rear tire is wider, the front will not come close to it's maximum lean angle. It's just not physically possible. The difference on my CBR is almost comical. Quite frankly, I don't want the front tire anywhere near its limit. The rear can loose a bit of traction and its recoverable. The front, not so much. I think the Dunlops may be more prone to cupping; I was hoping to use the Bridgestone radials to compare but the lack of the 150/70 over here got me to try the BT45. No tire pressure issues; I check pressure before every ride and have an air compressor and receiver in my garage, so no excuses not to have them exactly right before every ride. Always ran 36 psi front.

It is physically possible to use more of the front than with aggressive trail braking at lean, especially at track or supersport tire pressure settings; under heavy braking the front tire's contact patch can double in size whilst straight up and can still get grow enough during deep cornering/braking to compress the sides of the front tire to very close to the edge. Supersport tires vary quite a bit with some front tires falling off almost to vertical, but under heavy braking/cornering loads this will flatten out a great deal.

Riding style, tire pressure, brand of tire, all of it figures in.

 

[flynrider]

BT54's are readily available stateside; check out http://motorcycle.chaparral-racing.com/search?w=bt54, among others. Prices are quite good, too. You're just limited to the stock sizes.

This thread was initially posted to talk about how much I like the BT45's with the 150/70 rear. I still do, but there was a concern I had regarding tire clearance.

This seems to be resolved and I can't determine that there is any lack of clearance. Marks on the tire were apparently from some other cause.

The combination works very well, I like the handling better with the beefier rear tire with more available sidewall. Overall gearing also goes up a little, so your fuel mileage will improve a little over the stock tire. Acceleration doesn't seem to be affected noticeably.

As with anything, departure from stock can cause anomalies. The rest of this thread explains the situation.

YMMV

I have the Bridgestones from the factory with almost exactly the same miles. I don't see any weirdness with the tires; I'm not sure what you mean by cupping? Were your tires under-inflated by any chance? The recommended pressure is quite high (42 psi if memory serves).

Quote:, and the rear was not quite wide enough to match the lean angle available from the front.
That's the way every motorcycle I've ever seen is. As long as the rear tire is wider, the front will not come close to it's maximum lean angle. It's just not physically possible. The difference on my CBR is almost comical. Quite frankly, I don't want the front tire anywhere near its limit. The rear can loose a bit of traction and its recoverable. The front, not so much.

I have the Bridgestones from the factory with almost exactly the same miles. I don't see any weirdness with the tires; I'm not sure what you mean by cupping? Were your tires under-inflated by any chance? The recommended pressure is quite high (42 psi if memory serves).

Quote:, and the rear was not quite wide enough to match the lean angle available from the front.
That's the way every motorcycle I've ever seen is. As long as the rear tire is wider, the front will not come close to it's maximum lean angle. It's just not physically possible. The difference on my CBR is almost comical. Quite frankly, I don't want the front tire anywhere near its limit. The rear can loose a bit of traction and its recoverable. The front, not so much. I think the Dunlops may be more prone to cupping; I was hoping to use the Bridgestone radials to compare but the lack of the 150/70 over here got me to try the BT45. No tire pressure issues; I check pressure before every ride and have an air compressor and receiver in my garage, so no excuses not to have them exactly right before every ride. Always ran 36 psi front.

It is physically possible to use more of the front than with aggressive trail braking at lean, especially at track or supersport tire pressure settings; under heavy braking the front tire's contact patch can double in size whilst straight up and can still get grow enough during deep cornering/braking to compress the sides of the front tire to very close to the edge. Supersport tires vary quite a bit with some front tires falling off almost to vertical, but under heavy braking/cornering loads this will flatten out a great deal.

Riding style, tire pressure, brand of tire, all of it figures in.

Thanks! I'd done a Google search for the stock sizes and all I came up with was U.K. sites.

 

[Red Mist_imp]

I did a test to see if I could cause the tire to contact the inner fender where I suspected it had done so in the first place. I set the suspension to the softest position, marked the area I thought was causing interference with a black marker, and rode the bike on my local rough test road. Considering the suspension was set to its softest, I figured it would bottom out and create the issue if it was still present after my field engineering efforts (with a hammer) to create a couple of additional millimeters of clearance.

I saw no indication at all of any kind of contact. It may be that my modification worked, or that the marks were made while the tire was being installed and I just missed them (and they were coincidentally aligned exactly with the inner fender protrusion), or that high speeds with commensurate diameter expansion are necessary to replicate the issue.

Either way I am going to monitor but do not recommend any other size but stock.

We used to see the same problem mounting certain front tires back in the days when things weren't quite standardized; I recall my VFR750F burned a groove in the underside of the front fender when fitting the Metzeler Comp K Laser tire, after being ridden at high speeds. This was not really too unusual.

 

[Red Mist_imp]

If the suspension travel is in fact 3.5" then there is no way the 150/70 tire could possibly contact any part of the fender. Perhaps the groove running down part of the center of the tire was caused by the mounting process or something else is amiss.

Anyone else out there try any other tires but what came on the bike stock? Here again, based on the suspension travel, the fitment of the 150/70 should have been absolutely fine.

I see there are about a thousand forum members here; somebody's got to know something...

 

[rmack_imp]

If the suspension travel is in fact 3.5" then there is no way the 150/70 tire could possibly contact any part of the fender. Perhaps the groove running down part of the center of the tire was caused by the mounting process or something else is amiss.

Anyone else out there try any other tires but what came on the bike stock? Here again, based on the suspension travel, the fitment of the 150/70 should have been absolutely fine.

I see there are about a thousand forum members here; somebody's got to know something...

Seems a bit odd without seeing it but I have had a 150 rear since day one for a total of 8500 kms no problems heap of clearance

 

[Deanohh_imp]

How come problems with funny noises, wind buffeting, vibrations, etc always happen "at speed"? Why can't we ever know what the speed actually is? How fast is at speed anyway?

regarding marks on the fender, why would someone lift a wheel 3.5 inches too high when putting the wheel on. And if they did, how would that leave a mark? What about marks on the tire?

and if black marks on the fender come from the tire and you put a black marking pen on the spot to see if the tire rubs and leaves a black spot, what's that going to tell you when either way you're looking at a black spot?

and are the shocks bottoming out or not?

 

[Red Mist_imp]

How come problems with funny noises, wind buffeting, vibrations, etc always happen "at speed"? Why can't we ever know what the speed actually is? How fast is at speed anyway?

regarding marks on the fender, why would someone lift a wheel 3.5 inches too high when putting the wheel on. And if they did, how would that leave a mark? What about marks on the tire?

and if black marks on the fender come from the tire and you put a black marking pen on the spot to see if the tire rubs and leaves a black spot, what's that going to tell you when either way you're looking at a black spot?

and are the shocks bottoming out or not?

Hi Deanohh, very good questions.

To answer: Well, shall we say the speed limiter was not quite active. An indicated 110 mph is the top speed reached on the "test" ride with freeway speeds averaging about 80 mph in most places. Total freeway about 130 miles.

I did the wheel install so I knew the marks did not come about that way; possibly something happened to cause the score mark either during shipment or during the mounting process.

The tire did not appear leave any kind of scuff mark at all on the inner fender. If you do have nothing else to do, take a look at the guard shielding the taillight wire where it penetrates the fender into the housing. The right side of this "guard" is a sharp edge about an inch long, in line with the rotation of the tire. The score mark on the tire was/is just about exactly in line with this sharp edge. That's why, to be on the safe side, I removed my recommendation to use these tires until I had a chance to thoroughly investigate.

The chrome inner rod on the shock has at some point bottomed out as can be see from the marks on it (dust is pushed all the way to the rubber donut on the top of the shock). When this happened is hard to say, though.

My mechanic, an ex-marine aviation technician who worked on Harriers and is sharp as a tack, looked over the wheel and tire today and noticed the same possible contact point (edge of taillight wire guard). Like me, he concluded that there was no possible way the tire could move up far enough to contact the inner fender even if the suspension bottomed out. He had me sit on the bike and bounce to get a sense of this and was certain it was not possible.

I measured the remaining travel on the shocks with the bike on a rear stand, the shocks being partly compressed about .75 inches. There was 2.75 inches of travel left, and the distance from the tire surface to the edge of the guard was just under 5 inches. Thus there seems to be no way the guard could have contacted the tire, nor could the tire have contacted any part of the fender at any time. We figure the score mark being aligned with the guard edge is coincidence, and that the mark most likely occurred during my ride.

I put about 80 miles on the bike today "at speed" (per my description above) and there is absolutely no sign of contact or any further issues.

The tires work very well but because of this anomaly I retract my recommendation for anything but the stock sizes, although I still suggest the BT45 as a good option.

However as the BT54 radials are readily available in the stock sizes and are actually a bit cheaper at some outlets, those would probably be a better choice.

If the suspension travel is in fact 3.5" then there is no way the 150/70 tire could possibly contact any part of the fender. Perhaps the groove running down part of the center of the tire was caused by the mounting process or something else is amiss.

Anyone else out there try any other tires but what came on the bike stock? Here again, based on the suspension travel, the fitment of the 150/70 should have been absolutely fine.

I see there are about a thousand forum members here; somebody's got to know something...

Seems a bit odd without seeing it but I have had a 150 rear since day one for a total of 8500 kms no problems heap of clearance

Thanks for that, confirms my findings and sets my mind a bit more at ease. See my later post for an update on what we found today.

 

[thumper_imp]

If the suspension travel is in fact 3.5" then there is no way the 150/70 tire could possibly contact any part of the fender. Perhaps the groove running down part of the center of the tire was caused by the mounting process or something else is amiss.

Anyone else out there try any other tires but what came on the bike stock? Here again, based on the suspension travel, the fitment of the 150/70 should have been absolutely fine.

I see there are about a thousand forum members here; somebody's got to know something...

Seems a bit odd without seeing it but I have had a 150 rear since day one for a total of 8500 kms no problems heap of clearance

So, did you remove the brand-new 140 rear tire on your bike without ever riding it?

:huh:

 

[rmack_imp]

Sure did , removed the wheels had them done in gold and fitted 150 Dunlop road smarts front and rear for 3000 kms then fitted current ones conti cr specs

 

[Red Mist_imp]

Sure did , removed the wheels had them done in gold and fitted 150 Dunlop road smarts front and rear for 3000 kms then fitted current ones conti cr specs

How were the Road Smarts?

 

[rmack_imp]

Sure did , removed the wheels had them done in gold and fitted 150 Dunlop road smarts front and rear for 3000 kms then fitted current ones conti cr specs

How were the Road Smarts?

How were the Road Smarts? excellent no problems wet or dry

 

[Red Mist_imp]

How were the Road Smarts?
[/QUOTE]
excellent no problems wet or dry
[/QUOTE]Great, thanks for that mate

 

[Aussieflyer]

Hey Red Mist and all, I've never used BT45s and for that matter I've not yet had the standard fitment tyres near their grip limits however I was wandering if the BT45 is a more sport oriented tyre than the standards. I dont care at all about mileage but do care a lot about grip and happy to sacrifice longevity and economy for more sticky rubber. Any advice is appreciated.

 

[Red Mist_imp]

Hey Red Mist and all, I've never used BT45s and for that matter I've not yet had the standard fitment tyres near their grip limits however I was wandering if the BT45 is a more sport oriented tyre than the standards. I dont care at all about mileage but do care a lot about grip and happy to sacrifice longevity and economy for more sticky rubber. Any advice is appreciated.

Negative. The radials (BT54, stock tires) will generally always be an improvement in ride, grip, and handling. But the BT45s are a new generation bias-ply and do work extremely well. I grew up on bias-ply tires and whilst I only have the one bike now that is fitted with them (aforementioned CB1100) I've found them to be and excellent match with the technology and mission of the Honda. We rode sportbikes in the 1980s with tires that didn't have near the grip of these BT45s.

I've got about 500 miles of all kinds of riding on these tires, with the 150/70 rear, and really like them. No issues other than the initial concern regarding clearance, and that was a false alarm.

However, the stock BT54s are available and are probably better, so why not just stay with them? That's what I'll be doing when I get tired of looking at these BT45s.

 

[Rolls_imp]

Great info, Red Mist. I was wondering about just the issues Flyer raised and you addressed. Much appreciated.

 

[Aussieflyer]

thanks Red Mist. Good point in respect to how our standards keep improving as do our expectations ... today's touring tyres are better than yesterday's sport tyres. My tyres are still new with only 800 KMs on the clock of my CB and who knows what replacements will be available by the time I've worn these out.