Topic: BT45 speed ratings

[Whaleman]

I tried the search and could not find the exact answer. I want a set of BT45's for my 72-CB750 with Lester wheels (stock size). It appears I can only get the front 100/90-19 in V speed rating. For the rear 110/90-18 I can get H or V speed rating. I always thought that H was better for a CB750 as it was a somewhat thicker tougher tire as it did not need to lose as much heat at high speed. Should I get a V front and a H rear or stay with V on both. Thanks

[Frostyboy]

How quick do you intend to ride this bike?  I've got BT45's on my 550, I'm not sure if it's the same where you are, but I can still buy imperial fronts here. I have imperial on the front & a metric rear. Both are H rated, well in excess of what I need for the speeds I travel. 

[Duke McDukiedook]

Drop a letter rating for tubes.

[Frostyboy]

Drop a letter rating for tubes.

Did not know that, thanks. 

[Whaleman]

OK, I have done some research on this. Below is a email from Brigstone's Engineering manager.
Dan,
We do not typically recommend mixing speed ratings since different constructions can affect handling performance.
I would recommend one of the following:

1) 120/90-18 rear - available in V speed rating to match the front. The Overall Diameter difference, front/rear, is 0.1" more than the stock sizes and the Tread Width is 0.5" wider. The 120 can be used on the stock wheel.
2) The Spitfire S11 is available in the stock sizes (H speed rated)- these are typically recommended for older traditional bikes like your CB750, whereas the BT45 is designed for Sport Touring and older Sport Bikes.
You can use a tube in the tubeless tires - you should install new tubes with the new tires.

BTW, I have a '77 CB750K - great bike.


Mark Kuykendall
Engineering Manager
Bridgestone Passenger and Light Truck Tires
Motorcycle Tires
Kart Tires
Bridgestone Americas,  Inc.

Then after doing more research I found Brigstone makes an BT45 OE tire and asked if that would work.

My email:
Mark, Could I use the 100/90H-19 your #001029 made for the 2002-2003 Triumph Bonneville?


His answer:
Yes, you could use the Triumph BT45 front with the replacement BT45 rear for an H speed rated combination.

Sorry, I missed that one in the line-up.

 

Mark Kuykendall

Engineering Manager

Bridgestone Passenger and Light Truck Tires

Motorcycle Tires

Kart Tires

Bridgestone Americas,  Inc.

I ordered a set of matched BT45's in H rating from Bike Bandit. They promised the tire would be only 1 month old when shipped. I had Dennis Kirk check the date code on these same tires and one was over 2 years old. Dan