GPz900r & Dunlop Roadsmart 2/3 Review

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GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Sat Apr 25, 2020 12:03 am

FYI at this tyre change the RS3 was available for the 18" rear, so on recommendation I went that plus an RS2 on the front replacing my previous Bridgestone BT45 & Avon Cobra combo.

The difference is enormous, the bike is significantly more agile and tips in much faster. First gentle ride, and since I now can't hit an apex for quids (almost hit two kerbs as well) it's obviously going to take time to get used to them.

But curiously *already* I'm not so sure I prefer them.

Yep, I understand having the bike turning in quicker and cornering with less lean angle seems like a good idea, but it's actually made the ride less enjoyable. My first reaction is.....boredom!

The previous combo tyres were definitely not as agile at but they were lots of fun - incredibly secure mid turn and you could really tip her over with confidence. (I get my rears to about 8mm from edge). I just can't imagine how fast (or how poorly) I'm going to need to be riding on the Roadsmarts to replicate these lean angles.

And the RS tyres are much, much harsher on the bike. They transfer more bangs and crashes, and mid-corner road imperfections, even at low speeds, require a lot more concentration and steering corrections whereas the BT45 just soaked them up without complaint. Disdain really.

I know these are 'sports' rather than cruiser tyres (avon) and I'm not having a go at Dunlop - as a sports (handling) tyre I'm thinking they are pretty good, amazing really. And straight line stability seems perfectly acceptable - at legal speeds anyway.

But ironically my first impression is they actually have reduced the enjoyment of riding the old girl.

I'll drop the tyre pressures and give them time (and add my experience), but I'm thinking its probably another example of how there's always a trade-off with anything 'sporty'.

So food for thought if you, like me, needs new tyres for winter :-)
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Sat Apr 25, 2020 12:22 am

Came out of shop with recommended 38psi. I'm probably gonna drop front right down to 32psi and work up, at this point wasn't thinking of changing rear.
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Sat Apr 25, 2020 6:42 pm

OK, what a difference a day makes.

Didn't have my good tyre gauge handy so had to go and by one from the hardware store. Still felt like it's riding on a solid front tyre.....

It's hard to know just how accurate this gauge is, but after letting the tyres cool down for a couple of hours they consistently measured F42 & R46.

So I went for F32 & R38. Just went for a short ride (in the rain) and the change was quite amazing. Now the front rides over bumps rather than having them crash and unsettle the front. So a much smoother and much more enjoyable ride.

Obviously no high speed cornering yet.

What's more the wet grip, even on very new tyres, was excellent. Supposed to be a strong feature of these tyres and so far I can't argue. Definitely as good as the last set.

I'll keep tweaking the pressures as I bed these in to get the right balance, it seems like pressures do make a pretty big difference with these Dunlops. Not something I ever used to bother with (I know I should) but feeling much happier with these boots now :-)
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Mon Apr 27, 2020 1:35 am

Roads washed clean and a nice day to make a round trip (240km) along one of SA's iconic motorcycling roads - Bull Creek. Chicken strips measure 15mm so slowly getting there.

Rear first - my good gauge reads 37.5psi. The G always has a firm rear, and these tyres magnify everything, probably by 1.5x. I know all of the bad bumps on this route, and if you stayed in the saddle it would be really, really uncomfortable hitting these. The tyre is also bigger, raising the seat by about 15mm. I'll drop the pressure to 36 and this diameter change will also encourage me to get around to reducing the preload on the rear Hagon. So a bit softer and it will get my heels closer to the ground. Grip is better for sure, it no longer slides on a rare known (low-speed) surface transition like the Avon used to (not that it was bad)

Front reads 32psi. Doesn't feel at all soft or squirmy though and the grip - well there's clearly plenty. Handling not quite as sharp as with the higher psi, but I still rate the increased agility at least 2 steps better than the BT45. But even dropped to 32 the ride is also at least 2 steps harsher, which equates to more physically demanding riding, even when not pushing hard. No preload adjustment on the A8, so even though it's seem low I'll probably just leave it at 32.

So I would classify these Dunlops as sports-sports-touring tyres - i.e. an emphasis on sports. Would I ride these to Melbourne? Preferably not. They definitely help in the curvy stuff, but I wouldn't like to spend a full day in the saddle with these, especially on roads I don't know. The old combo was much more comfortable.

So where does that leave it?

Well I consider the Dunlops as just different to the old combo, not better or worse. As most of my riding is only a few hundred kms I'll live with the harsher ride - it does make me think I'm riding a sportsbike now! The increased agility makes cornering 'easier' because you have a lot more in reserve and it clearly improves changes in direction - the old girl does weigh 222kg.

But with the harsher ride overall it's a dead heat.

The old combo was softer but still no slouch in the corners, you just had to be more precise picking entry lines and use your body weight laterally more. But it was also far more tolerant of mid-corner bumps and much less physically demanding.

And in terms of overall fun the old combo probably wins out.

Would I buy these again? Well these tyres are probably more in the GPz genetic code, they cost about the same so if the mileage is comparable then yeah - I would.

But I can guarantee that at some point I'll get tyred of the harsher ride and change back - the old combo was really, really good.
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Mon Apr 27, 2020 3:49 pm

Last notes.

Dropped the rear tyre pressure just 1.5psi and immediately seat height felt like it was before. So I'm thinking it can't have been as much as 15mm, but its a noticeable change. Reinforces that these tyres are quite sensitive to tyre pressures.

I had read other reviews that mentioned high-speed wobble on some bigger cruisers. Well I just gave them a blast and they were exemplary, absolutely nothing to report here. If you wanted to go faster than that on a public road and on a cruiser bike then I humbly suggest tyres aren't your major concern!

However this may also be related to the lower front tyre pressure I'm running, as several reviewers reported dropping the front from the default pressures seemed to sort it.

So I'll probably have to pay more attention to tyre pressures, which is probably a good thing anyway :-)
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby BrettZZR » Mon Apr 27, 2020 6:29 pm

I'm always amazed at how different the different tyres make the bike "feel"! It seems like it shouldn't happen. But always after at first feeling amazed at the difference, and wondering if I'll ever get used to them, I do and they feel right again...

(-B'
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Thu Apr 30, 2020 5:25 pm

Cheers Brett. Funnily enough I went from the super grippy Conti Road Attacks to the Bridge/Avon combo last time - and I didn't recall noticing such a big change in the bike. Less grip of course (the rear grip with the Conti is amazing), but I'm guessing that the Contis construction is also 'softer' than the Dunlops.

The challenge with the GPz is the limited range of 18" rear tyres available, as mentioned this was the first time a Dunlop was available.

The best performing tyre has, of course, been the Contis - but they just don't last very long! But it seems that if you want a sporty yet supple ride these are still the go.
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Re: GPz900r & Dunlop Roadsmart 2/3 Review

Postby lotii10396 » Sun May 10, 2020 8:50 pm

So the final choice is 29psi front and 33psi rear. As mentioned the rear isn't such a big deal but I definitely notice the sweet spot for the front is between 28 and 30. From what I recall the recommended pressures for the G is +4 at the rear so I've just let the front set the rear. So clearly pressures is something I'll have to keep a closer eye on, but I reckon the extra effort is worth it if you also have a GPz as it definitely improves the handling and agility of the bike with an acceptable drop in comfort.
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