Interesting small feedback about Bridgestone BT023 GT vs PR2..

[Fred W]

I have tried running the pressures from the 1st gen manual and the front end felt mushy and required a lot of bar pressure in corners, at least initially. Maybe it would have gotten better if I had just let the tires heat up fully and the internal pressure to build up on its own?

 

[SkooterG]

I have tried running the pressures from the 1st gen manual and the front end felt mushy and required a lot of bar pressure in corners, at least initially. Maybe it would have gotten better if I had just let the tires heat up fully and the internal pressure to build up on its own?

That was my experience too. It's been so long since I tried the lower pressures, maybe I will again sometime when running the twistys aggressively. I wonder, and think it most likely does, if tire brand and model will have an impact on feel at various pressures.

Or maybe Yamaha just got it wrong on the recommendations for the Gen I? I mean I see no reason to raise the recommended tire pressures from Gen I to Gen II.

 

[Fred W]

Maybe the tire brand/model matters, especially considering what was available 10 years ago vs today, but the ones we sport tourer types are apt to use now are all pretty close in heat performance, I think.

I suspect that it was more of a mistake to publish those lower pressures back on the 1st gens, and they just realized it with the new model in 2006.

 

[Spud]

Gen I's have a lower pressure because the furnace blast of heat from the motor cooks the tires raising the PSI once it starts.

The superior Gen II does not cook the tires (or rider) and thus requires a higher initial pressure.

 

[Mihalis fjr]

Gen I's have a lower pressure because the furnace blast of heat from the motor cooks the tires raising the PSI once it starts.
The superior Gen II does not cook the tires (or rider) and thus requires a higher initial pressure.

 

[MCRIDER007]

Gen I's have a lower pressure because the furnace blast of heat from the motor cooks the tires raising the PSI once it starts.
The superior Gen II does not cook the tires (or rider) and thus requires a higher initial pressure.

That is an interesting theory but the engine heat has to go somewhere and the GEN2s route the heat under the rider and towards the rear tire.

 

[Redfish Hunter]

Gen I's have a lower pressure because the furnace blast of heat from the motor cooks the tires raising the PSI once it starts.
The superior Gen II does not cook the tires (or rider) and thus requires a higher initial pressure.

That is an interesting theory but the engine heat has to go somewhere and the GEN2s route the heat under the rider and towards the rear tire.

No, he is correct. The POS Gen1 was so slow it did not create enough airflow to route the heat backward through the bike and away from the front tire.

My (serious) theory is that the Gen1 leaned more to the Sport side of Sport/tourer and the lower pressure was consistent with what they thought their target buyer wanted. Little did they know it was going to be a bunch of "Old Guys". When they redid (refined? upgraded?) the Gen 2, they had a better feel for who was buying the FJR and how it was being ridden.

 

[SkooterG]

No, he is correct. The POS Gen1 was so slow it did not create enough airflow to route the heat backward through the bike and away from the front tire.

THIS ^^^^ coming from a guy that rides the fat pig of an ST1300. Anybody who rides an ST1300 must not have much of a mother!

My (serious) theory is that the Gen1 leaned more to the Sport side of Sport/tourer and the lower pressure was consistent with what they thought their target buyer wanted. Little did they know it was going to be a bunch of "Old Guys". When they redid (refined? upgraded?) the Gen 2, they had a better feel for who was buying the FJR and how it was being ridden.

You might be on to something here......

 

[kamal]

I have tried running the pressures from the 1st gen manual and the front end felt mushy and required a lot of bar pressure in corners, at least initially. Maybe it would have gotten better if I had just let the tires heat up fully and the internal pressure to build up on its own?

+1

I have been running 40/42 in my PR2s since Fred came down from the mountain with his findings.

 

[20valves]

My (serious) theory is that the Gen1 leaned more to the Sport side of Sport/tourer and the lower pressure was consistent with what they thought their target buyer wanted.

The Gen II bikes with their longer swingarm had more front end weight bias which could also be a reason. Then again, the Gen III bikes are back to 36psi front tire recommendation from the Gen II's 39psi..

 

[Fred W]

I have tried running the pressures from the 1st gen manual and the front end felt mushy and required a lot of bar pressure in corners, at least initially. Maybe it would have gotten better if I had just let the tires heat up fully and the internal pressure to build up on its own?

+1

I have been running 40/42 in my PR2s since Fred came down from the mountain with his findings.

:lol:

I have a striking resemblance to Charlton Heston, eh? Too bad I don't have any of his money.

My (serious) theory is that the Gen1 leaned more to the Sport side of Sport/tourer and the lower pressure was consistent with what they thought their target buyer wanted.

The Gen II bikes with their longer swingarm had more front end weight bias which could also be a reason. Then again, the Gen III bikes are back to 36psi front tire recommendation from the Gen II's 39psi..

Nah, I'm not seeing that. The length of the swingarm doesn't put more weight on the front unless the ride height in the back is higher (it's not) or the front is lower (it's not).

OTOH, the second gen piggy is heavier than the 1st gen piglet by about 30 lbs (or ~ 5 percent in round numbers), so that might account for about 2 psi difference front and rear.

 

[20valves]

...The length of the swingarm doesn't put more weight on the front unless the ride height in the back is higher (it's not) or the front is lower (it's not).

Why do drag bikes run extended swingarms then?

 

[bgross]

...The length of the swingarm doesn't put more weight on the front unless the ride height in the back is higher (it's not) or the front is lower (it's not).

Why do drag bikes run extended swingarms then?

Likely more than one reason, but steering stability comes to mind.

 

[Fred W]

...The length of the swingarm doesn't put more weight on the front unless the ride height in the back is higher (it's not) or the front is lower (it's not).

Why do drag bikes run extended swingarms then?

A longer swing-arm will result in less tendency for the front wheel to lift off the ground under acceleration, but I believe that is primarily because of the longer lever it represents to the weight (torque being applied to the ground at the rear wheel) not because there is more weight on the front tire to begin with.

 

[AVGeek]

I had Metzlers on the 08 FJR, and went through two sets before I caught a smoking deal on the 023 GTs. The first two days I had them on the bike, we had two intense days of rain here in the valley, and even though they were fresh, I didn't have a single slip, wiggle or other pucker inducing moment. The dry traction is also very predictable. I run ~39-front/42-rear (based on the manual recommendations, and bad cupping on the Metzlers), and have over 5000 miles on this set and they still look near new...

 

[Dr. Joe]

...The length of the swingarm doesn't put more weight on the front unless the ride height in the back is higher (it's not) or the front is lower (it's not).

Why do drag bikes run extended swingarms then?

A longer swing-arm will result in less tendency for the front wheel to lift off the ground under acceleration, but I believe that is primarily because of the longer lever it represents to the weight (torque being applied to the ground at the rear wheel) not because there is more weight on the front tire to begin with.

+2, Just a matter of physics... you have a wheel torquing in one direction at high rev and trying to move forward. If you'd have a 1 foot swingarm, you'd flip on your butt in less than 1/2 sec. The longer swingarm enables you not to flip up, and move forward... no more weight on the front.