rode with tire underinflated - advice needed

[USERNAME]

fellow bmw enthusiasts,

i am stupid/pissed. i looked in the little booklet that came with my bike, the 'technical manual' and checked the air pressures for my tires. for the front it reads, '14.9 psi' (it might be 14.6) whatever. that seemed low to me, but i thought, 'well, im new to motorcycles.' so i reduced the pressure to ~15psi. (it was at 25.) it's been nagging at me for a few days, and i thought, 'i'll check that again.' i checked the 'riders manual' and it says 31.something. son of a!!! so ive ridden the bike for about 300 miles with the pressure at HALF what it is supposed to be. i've read other posts/threads and people are pretty uniformly emphatic that when this happens, replace the tire, because riding underinflated drastically reduces the life of the tire.

one, im mad as hell that i didnt double check when i thought it was a goofy number.

two, im mad as heck that the manual is so blatantly wrong. well, one of them is. the 'technical' one. grrrr.

three, i'd like to hear for sure that i would be insane to do anything other than replace the tire before riding again. (i'll ride it to the shop...)

im chalking this one up to experience. i have no (huge) issues with just replacing the tire, but i wanted to hear from a few folks here before i did. should i absolutely positively replace it?

i got the bike used. it has dunlops on it. im ignorant as to whether those are the original tires or not, but im pretty sure they are.

please weigh in while i go read the 'front tire replacement recommendation' archives.

thanks.

 

[darrylri]

You don't say what bike you're riding, but for the late model bikes, even 31 sounds low.

I would be concerned about it, but if you really heated the tire up over 300 miles, I think it would be obvious.

I had a rear tire flat on my R1100RS, while I was doing 75+(+) on the M25, which is a huge, wide freeway ringing London. I didn't even notice it at first, but once in a while it felt a little bit loose. Finally, I pulled off at a service station, and as soon as I dropped the speed under about 50 it was obvioous I had a flat.

When I got stopped, the tire was completely melted, all the way around, from side to side! There was no mistaking that I needed a new tire.

That was after only about a 20 mile ride. I plugged it and then rode it back about 10 miles to get a new tire. Gotta love them stiff walled radial tires! ;-)

If your tread and your side walls look good, I'd keep an eye on it but otherwise use it up.

 

[USERNAME]

thanks

thanks darryl. it's a 2002 r1150r.

the thing that worries me is that the tire is diminished, but not damaged. thus while it appears ok, it's endurance and durability characteristics are degraded. i may have read it on the advrider forums, but someplace, a guy had a similar issue, but for some reason i thought more severe, like he rode it partially flat, or some such. anyway, the people on that forum freaked out and told him to replace it asap.

i think it is similar to the problems we've had over here with ford explorers rolling over. they may not report that on your side of the pond, but we had an inordinate number of people die in roll-over accidents after their SUV tires (firestones) de-treaded. further investigation revealed that tires were under inflated and their life dropped dramatically due to it. the thing is, those were 1,000s of miles of use, maybe ten of thousands.

but my gut feel is, if i only get two tires, i want em both in tip top shape. i have a few hundred bucks to fix it, but i dont have a strong desire to be fed through a tube.

but im still interested in what people have to say/their experiences.

 

[darrylri]

Re: thanks

i think it is similar to the problems we've had over here with ford explorers rolling over. they may not report that on your side of the pond, but we had an inordinate number of people die in roll-over accidents after their SUV tires (firestones) de-treaded.

I'm not sure which pond you're refering to, between Texas and California... I was in the UK on a vacation when it happened. ;-)

but my gut feel is, if i only get two tires, i want em both in tip top shape. i have a few hundred bucks to fix it, but i dont have a strong desire to be fed through a tube.

If you're concerned about it, then the money is a cheap way ease your mind. With the experience I had, I wouldn't be quite so concerned.

 

[dlearl476]

for the front it reads, '14.9 psi' (it might be 14.6) whatever. that seemed low to me....
two, im mad as heck that the manual is so blatantly wrong. well, one of them is. the 'technical' one. grrrr.

three, i'd like to hear for sure that i would be insane to do anything other than replace the tire before riding again. (i'll ride it to the shop...)

I'd read that manual again. I have a sneaking feeling is says 14.5 BAR (or should anyway, but even that seems low)
A second point I'd like to make is that the pressures quoted in manuals are "recomendations" The pressures quoted by the tire manufacturers are more important, and even those are starting points. You should find the pressure that is right for you and the load you're carrying by making sure your hot tire pressure (after you've ridden 10+miles) is your cold tire pressure + 10%.

As for the replacement issue, it's all about your comfort level. I've ridden a plugged tire for 1500 miles, sometimes at triple digit speeds, just to prove to myself it can be done. It actually held air better than the tube type tires I have on my F650.
There are many who say you should only ride a plugged tire to the nearest store to buy a new tire. I don't buy it.
If it was MY tire, I wouldn't give it a second thought if it didn't show signs of deterioration (bubbles, blisters). OTOH, if I was the LEAST bit worried about it, I'd replace it. ~$100 is a small price to pay for peace of mind.

 

[darrylri]

Re: Re: rode with tire underinflated - advice needed

I'd read that manual again. I have a sneaking feeling is says 14.5 BAR (or should anyway, but even that seems low)

I had that thought as well, but 1 bar = 14.7 psi, and normal tire inflation is about 2.5 bar. I had to figure this out when I needed a new tire in Spain:

A second point I'd like to make is that the pressures quoted in manuals are "recomendations" The pressures quoted by the tire manufacturers are more important, and even those are starting points. You should find the pressure that is right for you and the load you're carrying by making sure your hot tire pressure (after you've ridden 10+miles) is your cold tire pressure + 10%.

This is a good way to figure out what pressure you really need.

 

[BMWRich58]

have a look at this:::

http://www.retread.org/TireRepair/index.cfm/Article/197.htm

 

[Mr. Frank]

Another inflation issue is having enough pressure to protect your wheels against damage from pot holes and major pavement irregularities. Most folks like to get that front tire into the high 30's. I run 38/40 when riding solo on my RT.

 

[jgr451]

I doubt you did any damage to your tire after only 300 miles.If you had,it should be visible...However poster who talked about better to be safe than sorry had a point.You might not feel confident unless you cahnge it.Cheap peace of mind.

By the way'that is only a mild stupidity!!Read the long post that started Has this ever happened to you, or Have you ever done this.That is all about slow speed or stopped fall downs!!I confess I contributed my stupid story.Now I feel better cause I know it won't happen again!!