I finally installed the 160/70X ZR17 Z4 Metzler tire, still in scrubbing phase ( only 45 miles on it) and my first impression is WOW:th_image003: X 100%
Everything I expected is true and some more! it is really sad that people get sucked into the fat tire look and give no attention to performance then go buy a rear venture final drive when all that is needed is the correct sized rear tire! ( leave the rear stock height and lower the front from the fork and using 17 inch wheels !!!)
I also got sucked into the fat tire look and in all the researching I did,NO one ever mentioned this size tire, maybe because everyone is so fixated on a fat rear tire.
I too felt great after installing a rear 180/55XZR17 Z6 but soon discovered that something is not right, if it wasn't for the rubbing against the swing arm I would have been singing the 180/55 tune, the fat tire looks awesome BUT handling is not that hot if nimbleness and curves is what is desired! for straight line riding the 180 is good but you have to settle for the increased RPM, its not much but becomes a little irritating to always be at a higher RPM even if riding in a relaxed manner, the engine just feels like its laboring ( at least to me) some would go for a differential change which was never convincing for me, but this is a personal choice that each one of us has to take a decision for.
My assessment of the 160/70ZR17 size rear tire.
1- RPM back to normal since the tire is 9mm shorter than the stock 150/90X15 which is actually 4.5 mm difference in hight, compared to a 180/55X17 which is 3.2 cm that is a 1.6cm lower than stock! since the total hight of the tire has to be divided by 2 to get the actual hight difference when installed on the bike.
2- The 70 profile is a big plus as it provides more air cushion Vs the 55 profile
So the ride is more comfortable on less than perfect roads and easy on your back.
3- It also looks great unless you dream of fat tires.
4- The rear of the bike remains ~ stock hight , this together with one inch internal fork lowering and a 17 front 120/70X17 the weight bias of the bike is shifted forward as it SHOULD! so handling in turns is superb to say the least,Now the bike's handling is as close as it will get to a sports bike nimbleness and precision.
5- No need for notching the swing arm which in my opinion DOES weaken the swing arm, and no clearance issues at all( no washer swapping )
6- The bike is SWEET beyond words!, straight line stability is out of this world.
Conclusion: A+++ handling , engine RPM is the same as stock and happy, the rear height of the bike is maintained which also makes the bike lean easier than with the 180/55 tire, The front end stays put on the asphalts like the bike is on a rail.In a scale 1-10 I give it 10.
Some advice if going with Kosman wheels: ask for the welded Vs bolted wheels or else check the bolts torque every now and then , There is NO way a 90* valve stem can be used on Kosman rear wheel so ask Sandy at kosman if he can make a notch above the valve stem for clearance ( so you can use any kind of inflater found in gas stations and not just the round head one which is the only one that fits the current configuration).
the 160/70ZR17 size is a little hard to find but Z4, bridgestone, Avon and some others can be found.
All the talk is usually focused on the rear tire since the front stock wheel can accept an 18 radial, people tend to think of changing the rear wheel only and will reap the radial handling advantages well let me tell you,
THE MOST IMPORTANT BENEFIT IS FROM THE 17 INCH FRONT BUT SINCE THE 15 INCH REAR STOCK SIZE IS UN AVAILABLE IN RADIALS, BOTH WHEELS HAVE TO BE CHANGED TO 17 NO WAY AROUND IT!
I am now a fanatic 17 inch wheel user! nothing will ever change my mind to lean to an 18 inch wheel.
Don "oldman" is absolutely spot on to insist on 17 not 18 wheels, others using 17 wheels also become fanatic, its like "its a 17 inch thing" that no one will understand unless they try it or ride a bike that has 17 for a day or so not just for a spin.
For the 18 inch wheels fans, please don't feel bad about it,just change the front to 17 and you will be pleasantly surprised since the rear 18 wheel /tire combo keeps the rear ~ stock height but you will not be able to use anything but a 180/55X18
or bigger
For people that already changed the final drive to a venture a 160/70X17 will make the bike's RPM drop even further so in 5th gear you might be able to go 80 MPH at 3500 RPM but acceleration will suffer a little.
:eusa_dance: :band: :thumbup1: :cheers00: :banana: :smoke000: :nud:
the effect of 17 front on turning radius, rake and trail is what the doctor ordered for max handling! and specifically : front 120/70X17, rear 160/70X17
I still think Kosman for the price is the way to go but ask for WELDED wheels.
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uhwh
