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Tire pressure


MJDO

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Hello,

 

Hesitate to bring up a topic like this because I imagine there are a number of threads discussing it but could not find them.

 

Recently bought a new 2012 RT and was surprised at the relatively low recommended tire pressures. My previous bike was a Yamaha FJR 1300 which had recommended pressures of 39/42 psi, and my Honda VFR800 was 36/42. Rider only on the RT is 31.9/36.3 except with passenger and/or load, then it becomes the familiar (to me) 36/42.

 

Despite the fact that fully outfitted I weigh over 230 lb and generally have crap in the bags for any eventuality I've been running at the single-rider recommended pressures, which has included some pretty high speeds -- both in a straight line and in corners -- and the tires feel fine. Still, wonder about wear and heat buildup issues (in summer anyway).

 

Interested if anyone has some comment on this, and again, apologies if this has been addressed before.

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Welcome...this question comes up often. I think the consensus is the recommendation by BMW is generally on the low side. Beyond the consensus of too low, you will get a variety of answers and questions.

 

The pressures I use is 38F and 42R cold pressure. Regardless of load. Many more answers to follow :)

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I had a dealer put on my last set of PR3's. I asked about tire pressures. They said the LB PD puts in max cold pressure in their tires. I think they may have some insight.

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They said the LB PD puts in max cold pressure in their tires. I think they may have some insight.

 

That being that it's easier for you to lower the pressure to your preference than it is for you to raise it.

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I found early on the 32 psi for the front causes cupping right away.

 

I tried different pressures. 36 psi. cold would warm up to almost 40 warm. 10% increase. Just right. Long tire life, good traction and no cupping.

 

40 for the rear unless I have a passenger, then its 42.

 

My 12 R1200R calls for 36/42 no matter the weight. I ran that pressure for 6,000 miles on the first set. seems to work, the tires do not heat up as much as I would like.

 

Next set I will try 36/40.

 

Ymmv yadda Yadda

 

David

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I run 40/40 on my Michelin PR2 tires. I am currently at 12000+ miles and have probably 3000 to go.

I ride single and not agressively.

YMMV

 

 

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The Police bikes come with Run Flat tires according to the BMW brochure I read. So maybe that is why they run different pressures assuming they still use Run flat tires after the first set of tire changes.

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  • 2 weeks later...

I run 2.5 / 2.9 bar (or 36 / 42 psi) as recommended by

Michelin in the PR2s on my 2006 RT regardless of whether I'm solo, or two up with luggage.

 

No handling, or undue wear issues, and replace them after 10,000 or more miles, with between 1mm and 2mm tread remaining.

 

Oops wrong model......

The point I make though, is check the tyre manufacturers recommended pressures. It works for me. :)

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  • 2 months later...

That's outstanding mileage on the PR 2's!

 

I've been trying the major name brands and haven't been

real happy. After reading these posts, I may have been

a couple lbs or more low on the back.

 

I guess I was thinking the more pressure, the rounder the

tire with a higher crown in the center and the faster the

flat top type wear.

 

Any input on that one?

 

I got barely over 8k on the OEM's, did get 12k on Metz Z6 Interacts, only 8.5 on PR 3's (probly too low pressure on

the back espec on these), and 8.5k on Metz Z8 Int's. Tried to find another set of Z6 Int's but no more Int for the Z6's, so went with what they have now.

 

Just have a couple k on them so am going to try this 40 or + psi on the rear to see what it does. Seems to be flat topping awfully early, but that was with a little lower psi. I just went to 40 or + a dab cold, so we'll see how the flat topping does at that pressure.

 

I go about 270 dressed and probly haul around 20 lbs of "stuff" in the back side bags.

 

I don't consider myself Kenny Roberts by any stretch and want to live to put on lots more miles after I retire at the end of this year, so altho I do like to "ride with enthusiasm" that term is relative and my version isn't all that aggressive. BUT it remains that the centers always wear out, not the edges, so riding style doesn't seem to be playing a big part in it.

 

Thinking about it, I realized I'm on a road that's both rougher with lots of patches and has a coarser surface asphalt this year than I had before, so I imagine that'll hasten the wear I ride about 400 miles a week to work on that rough road so that's the bulk of the miles.

 

I've been interested in those PR2's and also the Pirelli Angels. Having put on 43k since May 2011, I'll probly find out about them pretty soon :-/

 

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Guest Kakugo
Hello,

 

Hesitate to bring up a topic like this because I imagine there are a number of threads discussing it but could not find them.

 

Recently bought a new 2012 RT and was surprised at the relatively low recommended tire pressures. My previous bike was a Yamaha FJR 1300 which had recommended pressures of 39/42 psi, and my Honda VFR800 was 36/42. Rider only on the RT is 31.9/36.3 except with passenger and/or load, then it becomes the familiar (to me) 36/42.

 

Despite the fact that fully outfitted I weigh over 230 lb and generally have crap in the bags for any eventuality I've been running at the single-rider recommended pressures, which has included some pretty high speeds -- both in a straight line and in corners -- and the tires feel fine. Still, wonder about wear and heat buildup issues (in summer anyway).

 

Interested if anyone has some comment on this, and again, apologies if this has been addressed before.

 

Michelin recommends running both the PR2 and the PR3 at 36psi (2.5 bar) front and 42psi (2.9 bar) on the R1200RT even when riding solo. Confirmed to me by one of their field reps. I tried running PR2's at the pressure recommended by BMW for solo riding and then at that recommended by Michelin and the bike just "feels" better with Michelin-supplied pressures. So far I have only run PR3's at the Michelin-specified pressure.

 

Always check with your tyre manufacturer.

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I run...(or 36 / 42 psi) as recommended by

Michelin in the PR2s on my 2006 RT regardless of whether I'm solo, or two up with luggage. ....

 

Ditto on my last three R1200RTs. Different tires, including PR2's. I use the same pressures in my Triuph Tiger, which is what Triumph recommends I recall.

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That's outstanding mileage on the PR 2's!

 

I've been trying the major name brands and haven't been

real happy. After reading these posts, I may have been

a couple lbs or more low on the back.

 

I guess I was thinking the more pressure, the rounder the

tire with a higher crown in the center and the faster the

flat top type wear.

 

Any input on that one?

 

SNIP

 

Its all about heat.

 

The lower the pressure, the warmer the tire runs.

 

The tires should heat up and build pressure 10% more hot than cold.

SO if you put the front at 35 cold and ride the bike 20 minutes. Stop check the warm pressure it should increase 10% or 3.5 lbs give or take a little.

 

If after riding the tire has 40 psi, then it is too low and needs more pressure cold. (tire is running warm)

If the tire only increases 2 psi then the tire is running too cold and should start out with less air so it flexes and heats up.

 

With non agressive riging, the colder the tire the longer it will last at the cost of traction. Its the usual trade off.

 

Car tires or bike tires the rule still applies.

 

Clear as mud?

 

David

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clip---

 

Its all about heat.

 

The lower the pressure, the warmer the tire runs.

 

The tires should heat up and build pressure 10% more hot than cold.

SO if you put the front at 35 cold and ride the bike 20 minutes. Stop check the warm pressure it should increase 10% or 3.5 lbs give or take a little.

 

If after riding the tire has 40 psi, then it is too low and needs more pressure cold. (tire is running warm)

If the tire only increases 2 psi then the tire is running too cold and should start out with less air so it flexes and heats up.

 

With non agressive riging, the colder the tire the longer it will last at the cost of traction. Its the usual trade off.

 

Car tires or bike tires the rule still applies.

 

Clear as mud?

 

 

Morning David

 

That 10% pressure change is just one of many quick-checks & is mainly used as a quick check for basic tire under inflation.

 

As a tire tuning tool it has limited use & can even show incorrect results.

 

Such as-- I can put 30 psi in my tires (cold @ 50°f), then ONLY back the bike out into the sun for 30 minutes at 80°f (not even ride it). That will more than likely give me about a 3 psi (10%) gain & I haven't even ridden the bike. 30 psi is too low but the 10% gain shows it as OK.

 

Same with checking the tires cold in the shade before riding then running 20 minutes on 100°+ hot asphalt. If I did the initial check cool in the shade then rode on sun heated 100°f asphalt I would have road surface temps heating the tire on top of the tire flexing heat.

 

For that 10% pressure rise to even come close to working the air temp must remain somewhat constant & the road surface must be close to ambient temp. Also for it to be anywhere near usable the ambient & road temps should probably be somewhere between 65°f & 80°f.

 

It is another tool but like other tools needs to be used with good common sense & a good understanding of it's limitations.

 

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On our 2nd set of PR3's here.

 

Run 40 up front and 42 in the rear 100% of the time two up or not.

 

1st set lasted 15,500 miles; 2nd set at about 9,400 miles and should last similar mileage.

 

PR3's in my experience is an Excellent overall performer.

 

08RT with almost 60,000 miles of SMILES so far

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