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Mixing PR5 and PR4 GT


Paul De

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My front tire is on its last legs and needs replacement. My '15 RT came with PR4 GTs and I have already replaced my rear with the same tire and it is maybe 1/3 into its usable life. After reading the tire threads and reviews I want to try the new RP5 front tire. While back in the bias ply tire days I did a fair bit of tire mixing even across brands, I don't want to stray too far with mixing radial tires on my RT. So, I'm going to try a small step experiment and will replace the front PR4 GT with a PR5 and then when the rear is wore out I'll replace it with a PR5 or a PR5 GT. I may have missed this being done already since I've been focused on work related travel, but I suspect I would be only one of a few trying this tire combo to date.

 

After considering that I never load the bike like a pack mule, nor run sustained speeds above 80 MPH, I'm coming down on the thought that for me and the way I ride I don't think I need the heavier GT carcass and blending between the PR tire series from Michelin is not going to introduce any significant stability problems. The only thing I might find is that I would need to inflate the tire by a few extra psi if I find the RP5 giving a squirmy feel on the RT.

 

The RP5 front goes on next week and I'll come back with initial impressions.

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Rider1200RT

Very timely post actually as I am in the same boat as you are. I have about 4K on my new rear 4GT but the front 4GT has maybe 500 -800 miles left. I got 12K out of the rear tire and about 15k miles out of the front by the time I put a new one on.

I would have to spoon the new tire on myself as the dealer and the tire place I go to will not mount the PR5 on the bike due to liability issues I guess.

Please let us all know how you like the new set-up!

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My front tire is on its last legs and needs replacement. My '15 RT came with PR4 GTs and I have already replaced my rear with the same tire and it is maybe 1/3 into its usable life. After reading the tire threads and reviews I want to try the new RP5 front tire. While back in the bias ply tire days I did a fair bit of tire mixing even across brands, I don't want to stray too far with mixing radial tires on my RT. So, I'm going to try a small step experiment and will replace the front PR4 GT with a PR5 and then when the rear is wore out I'll replace it with a PR5 or a PR5 GT. I may have missed this being done already since I've been focused on work related travel, but I suspect I would be only one of a few trying this tire combo to date.

 

After considering that I never load the bike like a pack mule, nor run sustained speeds above 80 MPH, I'm coming down on the thought that for me and the way I ride I don't think I need the heavier GT carcass and blending between the PR tire series from Michelin is not going to introduce any significant stability problems. The only thing I might find is that I would need to inflate the tire by a few extra psi if I find the RP5 giving a squirmy feel on the RT.

 

The RP5 front goes on next week and I'll come back with initial impressions.

 

Afternoon Paul De

 

You are going to mix a 120/70 front to a 180/55 rear & mix a 1/3 worn rear tire that now has a flat band worn in the center to nice new round cross-section front tire so the PR4 GT to a PR5 is probably the least of the effecting variables.

 

Your bike will definitely handle differently as replacing any worn tire with a new "anything" will change the handling.

 

I haven't ever mixed a PR4 GT with a PR5 but I have mixed & matched a LOT different motorcycle tire combinations in my long riding life & while I definitely have liked some combinations better than others not a one has been dangerous, or caused any major problems.

 

I believe that you will find that the biggest difference in feel will come from mixing a new round profile front tire with a partially worn rear tire but as you get some miles accumulated on the combo it will even out & then you won't notice it any more.

 

 

 

 

 

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Yeeha! Stephen

From the Michelin site:

 

"MICHELIN Road 5 Standard versus the GT version - The above sizes of MICHELIN Road 5 tires are designed for naked bikes and roadsters such as the Triumph Street Triple and the Suzuki SV650.

Heavier grand touring bikes such as the BMW R 1200 RT or the Kawasaki 1400 GTR require the GT version of MICHELIN Road 5, which will become available in 2019. Until then please choose MICHELIN Pilot Road 4 GT tires."

 

https://motorcycle.michelinman.com/motorbike/michelin/desktop/US/en/tires/products/road-5.html#

 

I just removed a Set of Road 5's from an R1200RS and you should see how flimsy the sidewalls are on the used 5's. You can wiggle them around with your bare hands. Not much weight support there.

 

You might hold off on that mixing experiment for now.

 

That said, I use a Pilot Power on the front of my RT with the 4 GT's out back. Shorter mileage, but it sticks very well and matches the mileage of the rear. 1 to 1 instead of 2 to 1...

 

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I just removed a Set of Road 5's from an R1200RS and you should see how flimsy the sidewalls are on the used 5's. You can wiggle them around with your bare hands. Not much weight support there.

 

You might hold off on that mixing experiment for now.

 

 

Thanks for sharing this Stephen, I could see a sidewall blowout as a result.

 

Jay

 

Edited by strataj
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Afternoon Paul De

 

You are going to mix a 120/70 front to a 180/55 rear & mix a 1/3 worn rear tire that now has a flat band worn in the center to nice new round cross-section front tire so the PR4 GT to a PR5 is probably the least of the effecting variables.

 

Your bike will definitely handle differently as replacing any worn tire with a new "anything" will change the handling.

 

I haven't ever mixed a PR4 GT with a PR5 but I have mixed & matched a LOT different motorcycle tire combinations in my long riding life & while I definitely have liked some combinations better than others not a one has been dangerous, or caused any major problems.

 

I believe that you will find that the biggest difference in feel will come from mixing a new round profile front tire with a partially worn rear tire but as you get some miles accumulated on the combo it will even out & then you won't notice it any more.

 

 

 

For sure I'm expecting lighter handling with a fresh tire profile up front. I was going to take that into account and comment more on handling neutrality and sidewall flex and, after scrub in, how much confidence it inspires to stuff it into a turn.

 

The comments warning me off the PR5 on a heavier bike have me nervous again... wondering if the service writer, or service tech will flag it a no go? So far they seem oblivious that Michelin does not recommend this tire on an RT.

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Well I chickened out and put on a PR4 GT. I was mulling this over before heading to the shop for the tire change appointment today and concluded that Michelin specifically advises the RT needs he the GT version on their website, so if I were to be unlucky enough to get a flawed tire, they would likely not stand behind the warranty . So, I bailed out on the PR5 experiment. Sorry there won't be any observations on the PR5 and the PR4 GT has been well covered.

 

Cluck Cluck Cluck -B' Gock!

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Lone_RT_rider
Cluck Cluck Cluck -B' Gock!

 

 

Awwwweeee man! We used to run biased ply on the front and radials on the rear when we were younger. What could go wrong?!?!?!

 

:rofl::facepalm:

 

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Cluck Cluck Cluck -B' Gock!

 

 

Awwwweeee man! We used to run biased ply on the front and radials on the rear when we were younger. What could go wrong?!?!?!

 

:rofl::facepalm:

 

Morning Lone_RT_rider

 

Probably nothing-- Harley even did that from the factory on some production bikes.

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I think we are all getting brainwashed by Michelin! If the $%^& tire is rated for the load range required on the bike....What could go wrong?!?!?!

 

I get that a stiffer sidewall would change the feel of the tire, but is that good or bad? I like a front tire with some "feel" to it.

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I had an 02R1150RT which is about the same weight as my 14R1200RT wethead. On my 02 RT I ran Road Pilots, Road Pilots 2's, Road Pilots 3's not a GT or spec heavy wight tire yet approved by Michelin. Sure I ran some other brand too also not spec heavy wight tires, never had a tire failure or issue. Just saying... But I trust Stephen on his comments about the 5's.

 

Jay

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I think we are all getting brainwashed by Michelin! If the $%^& tire is rated for the load range required on the bike....What could go wrong?!?!?!

 

I get that a stiffer sidewall would change the feel of the tire, but is that good or bad? I like a front tire with some "feel" to it.

 

The best explanation that I heard of the actual *why* the PR5 isn't recommended, despite the load range being sufficient, is that "handling was unsatisfactory at the limit." No further info was given, so is the "limit" could be the limit of weight capacity (meaning that the bike is fully loaded), the limit of adhesion of the tire, the limit of the rider's abilities, etc...?

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Well, like strataj says, why have the normal tires worked so well for us for all those years on bike that were heavier? While the rear of my '04 RT was a different size, the front is the same. I can tell you that the Dunlop Roadsmart 3 does not have a heavy weight option. I can tell you that the sidewalls are not as stiff when flexing them and feeling of them when ready to install them. I can also say they ride BETTER than the stiffer sidewall T-30 EVO GT spec tires and handle the best of any tire I have run on this current RT. I bought a set of the new T-31 GT Bridgestones, they are waiting to be put on. Now I wish I had bought the standard sidewall version. I didn't, because I have been brainwashed into believing heavy is better. If a tires sidewall was not heavy enough, I would think you could feel it move too much under certain conditions. You would certainly see a problem from it not handling loads from pothole impacts and allowing the rim to bend. I am seeing no sign of any of this.

 

If someone had problems with a PR5's "handling at the limit" on a new RT, wouldn't they have more or less the same result from running other brands of tires without a heavy weight spec? The Continental tires that came on my RT new....were NOT a heavy weight spec tire. I hated them, but handling when leaned over wasn't the problem at all with them.

 

If in fact a heavier sidewall tire was needed, why is it not simply rated differently? Instead of the "58" load rating just advertise the heavier tire with a "60" or whatever. Both having the same load rating just does NOT make sense to me.

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Afternoon__

 

So what's the difference between a fully loaded 1200R bike + 10% & a 1200RT partially loaded to less weigh than the fully loaded R bike?

 

Seems like if it's deemed safe (handling wise) on a fully loaded 1200R bike +10% then anything under that weight (correct for ft/rear) on a 1200RT should be just as safe.

 

At high speed I actually like the thinner side walls better as they build less heat at speed while running less air pressure.

 

I seldom if ever load my RT bike to max GVW +10% & on the few times that I ever have it is usually a short local lower speed run (like hauling a load of water-softener salt home from town). Last time I had a big load on my RT it was a large (over 400#) person on the rear seat & trust me I could barely hold the bike up at a stop let alone ride aggressively). The hardest part of that short trip was getting the person on & off the bike as I couldn't allow them to mount or dismount with bike on side stand due to side stand bending concerns & there was no way that person could get on the bike with a rider on the bike first.

 

When added side wall thickness is specified then usually higher nominal air pressures are also required to prevent flex & heat build up at high speeds.

 

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If someone had problems with a PR5's "handling at the limit" on a new RT, wouldn't they have more or less the same result from running other brands of tires without a heavy weight spec?

 

The handling at the limit comment came from someone at Michelin as an actual to "Why?", rather than just "because we say so". I will look for the source, but I think that its either already present in this forum or the BMW MOA forum - I got this info second or third hand, not directly. I personally asked "why?" via the Michelin US website and got a circular non-answer about heavy GT motorcycles requiring GT tires.

 

The reason I asked at all is because I, like you, question the fact that since the weight rating is the exact same on both GT and non GT versions of (for example) a PR4, then why are the GT tires required if the reason generally stated for the requirement is that the motorcycle is heavier? :dopeslap:

 

 

Edited by alegerlotz
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If someone had problems with a PR5's "handling at the limit" on a new RT, wouldn't they have more or less the same result from running other brands of tires without a heavy weight spec?

 

The handling at the limit comment came from someone at Michelin as an actual to "Why?", rather than just "because we say so". I will look for the source, but I think that its either already present in this forum or the BMW MOA forum - I got this info second or third hand, not directly. I personally asked "why?" via the Michelin US website and got a circular non-answer about heavy GT motorcycles requiring GT tires.

 

The reason I asked at all is because I, like you, question the fact that since the weight rating is the exact same on both GT and non GT versions of (for example) a PR4, then why are the GT tires required if the reason generally stated for the requirement is that the motorcycle is heavier? :dopeslap:

 

 

Afternoon alegerlotz

 

Something that you need to ask but they probably won't/can't answer is what is the tire weight rating at the BMW specified pressures?

 

A tire's max load rating is usually at max tire pressure rating (shown on the tire sidewall) & A MoCo almost never specifies nominal tire pressures anywhere near max tire pressures.

 

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If someone had problems with a PR5's "handling at the limit" on a new RT, wouldn't they have more or less the same result from running other brands of tires without a heavy weight spec?

 

The handling at the limit comment came from someone at Michelin as an actual to "Why?", rather than just "because we say so". I will look for the source, but I think that its either already present in this forum or the BMW MOA forum - I got this info second or third hand, not directly. I personally asked "why?" via the Michelin US website and got a circular non-answer about heavy GT motorcycles requiring GT tires.

 

The reason I asked at all is because I, like you, question the fact that since the weight rating is the exact same on both GT and non GT versions of (for example) a PR4, then why are the GT tires required if the reason generally stated for the requirement is that the motorcycle is heavier? :dopeslap:

 

 

Afternoon alegerlotz

 

Something that you need to ask but they probably won't/can't answer is what is the tire weight rating at the BMW specified pressures?

 

A tire's max load rating is usually at max tire pressure rating (shown on the tire sidewall) & A MoCo almost never specifies nominal tire pressures anywhere near max tire pressures.

 

 

Good question. Then again, most of us don't run the front tire at the BMW recommended pressure because it will cup so badly... instead it sounds like most run them 2 to 4 psi higher. Your point is valid, though... they don't publish a weight rating at particular pressure table, but that might help answer the "why" question.

 

At this point I run Metzeler Roadtec 01, so all of the PR5 situation is academic to me anyway.

 

Edited by alegerlotz
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Something that you need to ask but they probably won't/can't answer is what is the tire weight rating at the BMW specified pressures?

 

A tire's max load rating is usually at max tire pressure rating (shown on the tire sidewall) & A MoCo almost never specifies nominal tire pressures anywhere near max tire pressures.

 

 

That could be important. But the rear tire pressure is supposed to be 42 psi on the Wethead RT going by BMW specs. Which happens to be the maximum pressure on the sidewall of the Dunlop RS3 on the bike....and the max pressure of the Bridgestone T-31 GT rear tire sitting in the shop. Older RT's were 36 psi rear, except for when running loaded where they recommended 42 iirc.

 

Front tires also carry 42 psi max rating. But the BMW manual says 36 psi for the front with no designator for load changes. I don't figure the front tire picks up much extra weight if a 200 lb passenger and 75 lbs of gear are on the back of the bike?

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Well now I feel bad that I didn't have a balz to have the PR5 mounted and keep us all entertained and add some new info to the collective.

 

And I agree with the comments from Lone_RT ride, Dirt Rider and others that from a technical standpoint it should not have been a safe handling issue. I anticipated maybe a few more pounds of tire pressure to firm up the side wall to be a precise steering feel. The unlikely case would be a wonky feel that we talk about from our least favorite tires.

 

Nope, it was my all grown up (overly conservative) brain churning on what if I get a flawed tire and need to make a claim and Michelin weasels out based on their specific comment that the PR5 is not meant for the RT. Sad to admit I think in these terms in my mature years.

 

I was thinking the softer side wall might be a potential advantage to take that little tiny bit of harwb was out of the ride that I can't dial out with the ESA suspension w/o making the bike boat around like a ‘70s Lincoln Town Car.

 

Well maybe I'll grow a pair in the next 8K miles and try the non GTs front and rear.

 

BTW Not sure if it is the Telelever geometry on the waterhead, or the PR4 GTs tire itself, but when compairing worn to fresh tires back to back I was struck by how much handling consistency was retained through tire's life. My ‘99 RT handling would go off by midlife and become a beast In the last quarter of the tire's life.

 

 

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roger 04 rt

I test rode a 2018 RT with Metzler tires that handled much differently that my 2017 RT with PR4s. After that experience, I can't see myself trying PR5 on front or back or both. Also, I only ride solo with atmost full side cases so I think I'll go with the thinner sidewalk tires in the future.

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RecentConvert

I ride two up 90% of the time. When we are traveling distances, we are very near the GVW limit. The technical director at Dunlop asked the same questions being raised on this thread, but also provided some insight.

Tires are tested at max weight and max speed for the rating. So fully loaded for 30 minutes at 168 mph (speed rating W). I will never approach that speed (although I would like to try :)

The weight rating is a formula based on specifications such as tire volume, aspect ratio, and several other factors.

 

I like the Roadsmart 3, it handles great and predictably whether one or two up. 42 psi always in the rear. I've recently reinstalled a slightly used RS3 on the rear to replace a Bridgestone T31 GT. The Dunlop feels better, rides much less harshly, holds the initial line better, doesn't follow tar strips as badly. And that is while mated to a T31 with 8000 miles on the front.

 

I suspect the companies with both regular spec and GT spec tires have maximized feel for the regular spec tire to the point where they are nervous about the same construction on a fully loaded RT. Perhaps the RS3 doesn't feel as good on a lighter weight bike because its design parameter leans toward the heavier weight bike. Nothing but speculation here, but I was with Goodyear Corporate for a number of years....

 

These tires are all rated for 168 mph and tested to that. All of them are good tires, with different characteristics. Just keep them inflated correctly!

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I've been using Michelin Pilot Road tires for many years on my big sport touring bikes. And I usually get about 4000 to 5000 miles out of a back tire, and perhaps twice that with the fronts, although they get pretty uneven wear during the last several thousand miles.

 

Then, a few years ago, I had a puncture while on a long ride, and I needed to buy a new rear tire from a shop in Santa Fe. All they had was the PR4GT. At the time, my front tire was an almost new PR4. So, I tried the GT on the back. And what I found is that GT on the rear works fine on my R1150RT, and the wear is phenomenal! I've put about 5000 miles on it, and it still looks almost new.

 

So, I think maybe all this talk about load rating is beside the point. The primary benefit of the PR4GT is that it provides longer tread life. And the handling seems unchanged to me.

 

Cap

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RecentConvert

I had to retrieve my Tiger from the dealer this morning. While waiting there I was able to compare side to side a Road 5 vs Roadsmart 3 in 180/55-17. The Road 5 is about 2 lbs lighter. The Road 5 sidewall and tread feel downright wimpy compared to the RS3. None of the other tires of interest were in stock. After than comparison, I will wait for the GT version of the Road V to be available. Another set of RS3 to burn through.

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