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Michelin Launch PR4

27K views 91 replies 38 participants last post by  Riderman 
#1 ·
#70 ·
I waited until this morning to pull the trigger on tires to give the local bike shop the opportunity to give me a price on the PR4 GTs (he was way high) and when I went back to Revzilla the price had jumped from $339 for the pair to $370. Evidently Revzilla was running a sale which is now finished. I ended up buying from Competition Accessories, as their price for the pair was still just $341.
 
#72 · (Edited)
Yeah, I've done a bit of experimenting with "unusual" tire choices . . .

Yes, Aspect Ratio counts here, as does rim width.

There are some nice tire size calculators on the 'net. I find this one is easy to use.

A 190/55-17 is pretty close to a 205/50-17 (a very common car tire size), with a diameter difference of 0.6%. But that extra 15mm (0.59") gives a width increase of 7.9%.

Note that all of these are based on "standard" tire sizes, and individual tire brands and models can vary a small amount.

For example, I measured the actual width difference between the stock 190/55 Z8 rear and a 205/50 car tire mounted on the stock GTL rim as just under 3/4".

In terms of the K16, the single-sided Paralever swingarm has some room to go taller, but not much room to go wider. There are also some concerns where the swingarm curves in at the front corner of the tire.

In order to fit the Euro-profile car tire to the GTL, I needed to make a 3/8" spacer disk, and use longer lug bolts with special tapered adapters (those were a pain, as BMW uses the more unusual Fine metric thread).

It works, but the bike does handle a bit different. I can still push hard and never have had any traction concerns (in some cases traction is actually better, especially compared to the factory Z8), but it is an "acquired" taste. I have had a few friends think the car tire might slow me down some, but a local canyon ride usually takes care of that notion rather quickly. :D

I also played with a 130/80-17 "rear" tire mounted on the front. My thoughts were that the thicker tread would considerably increase mileage, although there are some concerns around the different compounds and profiles used, and the general weight differences between front and rear tires.

I chose to use a 130/80-17 Tourance tire, as it had good reviews and I wanted a more aggressive tread pattern for some dirt and gravel road work (yes, on the beast of the GTL).

What I found was that the tire fit between the Duolever forks, but the taller diameter interfered with the fender. I looked at making brackets to lift the fender 1/2"-3/4", but decided to just run my test with no front fender.

The bike rode fine, although it did steer a bit heavier. Traction didn't seem to be an issue, although I never pushed it to the absolute limit. It did work very well in gravel and soft dirt, as the K16's massive torque meant the 205 rear car tire just dug in and pulled hard, allowing the front's larger contact patch to float over the soft stuff. It was still a 700+ lb, limited-clearance enduro bike though, which meant it was a handful . . .

The biggest downside of that oversized front tire was that the 6.7% larger diameter threw off the wheel speed sensors. The larger tire rotated 6.3% slower for the same distance, which the bike interpreted as the rear tire rotating slightly faster than the front, so it constantly initiated the Dynamic Traction Control system. I was able to disable that (had to redo it on every startup), but even then, the ABS system flashed errors, and my cruise control wouldn't set.

That might be solved by using a Yellow Box (device that intercepts and modifies speed sensor readings to correct for Odo errors) on the front only, but I removed the larger tire before playing with that.

So yes, you can do some playing around with different tire sizes, but the disadvantages usually outweigh the advantages pretty quickly, so for most riders, it just isn't worth it.

 
#75 ·
They do Metzeler Tourance Next in sizes to fit the K16 if you need more grip on dirt tracks, but I doubt if they will be good for mileage?
Yeah, saw those, and I am curious.

But for my extreme rides, I need tires that can reliably run 14,000 miles between changes. The dirt/gravel roads are a small percent of those miles.
 
#76 ·
RL's post from 1/20 make me think the front 120/70/17 U I bought at Gulf Coast yesterday isn't a GT! The Michelin tag says Pilot Road 4, not GT. I asked twice and they said it was the (58w) that indicates the GT rating. The price was 144.99 and I thought it was about right. Looks like it's going back.
 
#80 ·
All 120/70-17 Pilot Road 4 tires have the 58W weight & speed rating.

The GT spec also has stiffer sidewalls and carcass for less flex on heavy touring bikes.

From Michelin's site, the U version is only available in the 120/70-17 front and 180/55-17 rear, which is not correct, as the K16 uses a 190/55-17 rear.

Take the tires back and get the GT version, as noted by RL. :)
 
#82 ·
RL / Ken thanks.

Bought the tire running errands in the car so have not mounted it. I bought a rear non B spec PR3 the same way, trusting what was said. I don't think that it was intentional either time but don't plan on letting it happen again. It'd be different if you needed a tire on the road and had to take what you can get in a pinch.
 
#83 ·
Most dealers hold to the "It's round band black and holds air" philosophy. If you're more picky than that (and many of us are) then it's up to you to confirm things by reading the actual tire itself.

Since you haven't mounted it yet, I'm sure they'll refund you or swap it out for the correct tire.
 
#87 · (Edited)
What's the difference between the 58W and 75W PR4 tires?
The number is the load rating and the letter is the speed rating:
58 = 520 pounds @ maximum pressure
75 = 937 pounds @ maximum pressure
W = speed rated @ 168 mph maximum
 
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