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Tire pressure vs gravel


Keith S

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I have done some searching on this topic but I can only find info for people riding GS's etc. What is the rule of thumb when it comes to reducing tire pressure when riding an RT or similar bike on gravel roads?

 

Thanks, Keith

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Keith, that's a pretty good question. I don't know of a rule of thumb for the RT. Being that RT's are about 10-20% heavier than GS's I'd hazard to guess that you could run 10-20% higher pressures than those recommended for GS's off road. Understand that this is a SWAG (Scientific Wild A$$ed Guess) and should be taken only as an off-the-cuff commentary.

 

There are several riders here who ride their RT's off road, so I'm sure someone will share their experiences.

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grasslander

Run it the same as the street unless it's muddy or sandy - then take it down 2-4psi.

 

All my road bikes have seen gravel. Just stay loose!

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Agree with grasslander - leave it be. You want at least the normal tire pressure if you hit a pothole hard, to protect your rim from being dented. I ride gravel often and regularly with my RT. It's a great and versatile bike in many ways, and this is one of them.

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Thanks for the info. thumbsup.gif I'm leaving this Saturday for Alaska and I figured I would come across gravel in the construction areas etc.

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I agree with the others, no need to adjust pressure but stay loose on the bars and look ahead for the deep stuff so you can avoid the worst of it. Also be easy on the throttle input, keep your momentum steady to avoid spinning the rear tire and try to do the same on the brakes (rear only can be nice at times if possible...my RT doesn't give me that option). Are you planning on doing the top of the world highway? I did it last year on a 1500 Wing with minimual drama. A truly amazing ride...enjoy yourself and take lots of photos!!

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I agree with the others, no need to adjust pressure but stay loose on the bars and look ahead for the deep stuff so you can avoid the worst of it. Also be easy on the throttle input, keep your momentum steady to avoid spinning the rear tire and try to do the same on the brakes (rear only can be nice at times if possible...my RT doesn't give me that option). Are you planning on doing the top of the world highway? I did it last year on a 1500 Wing with minimual drama. A truly amazing ride...enjoy yourself and take lots of photos!!

 

Yes I am planing on doing the "Top of the world" highway. I'll tell ya one thing, from doing the top of the world highway and the Cassiar it is the loose/deep gravel of the Alcan highway construction zones that concern me the most.

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I did it from Tok to Dawson City and actually the bumps were the biggest concern (granted this was a year ago). The over all condition of the road was very good (you should see my driveway) and I just kept it under 30 (often way under).....I skipped the Cassiar, it was raining hard when I got to the turn (heading south).

 

Here are some links to my ride reports if you are interested:

 

Day 1 http://bmwsporttouring.com/ubbthreads/showflat.php/Cat/0/Number/725150/an/0/page/0#Post725150

 

Day 2 http://bmwsporttouring.com/ubbthreads/showflat.php/Cat/0/Number/725661/an/0/page/0#Post725661

 

Day 3 http://bmwsporttouring.com/ubbthreads/showflat.php/Cat/0/Number/725824/an/0/page/0#Post725824

 

Day 4 http://bmwsporttouring.com/ubbthreads/showflat.php/Cat/0/Number/726667/an/0/page/2#Post726667

 

Day 5 http://bmwsporttouring.com/ubbthreads/showflat.php/Cat/0/Number/726669/an/0/page/2#Post726669

 

Day 6/7 http://bmwsporttouring.com/ubbthreads/showflat.php/Cat/0/Number/734914/an/0/page/0#Post734914

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Also be easy on the throttle input, keep your momentum steady to avoid spinning the rear tire and try to do the same on the brakes (rear only can be nice at times if possible...my RT doesn't give me that option).

I drove on gravel and while I was extremely uncomfortable for the first few miles, at the end of it I was doing 100mph for extended distances and sliding the rear with throttle. Here's what I learnt.

 

1. Steer with the throttle. It's counter-intuitive but it works. If you've seen dirt-track races, you know what I mean.

 

2. If you can get your ABS to fault it's even better because you can lock up the rear and get directional input for those times when throttle steer won't cut it. I was unable to get my ABS to fault.

 

Dirt tracking is fun. If you've never understood the concepts behind it, then you may have a hard time.

 

$0.02

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Perhaps closer to home, but out in the Yukon I'll pass....one good get off and you could be spending a very cold evening with the bears.....or worse.....

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Perhaps closer to home, but out in the Yukon I'll pass....one good get off and you could be spending a very cold evening with the bears.....or worse.....

 

I do agree that confidendce plays a large roll in how well you ride on gravel. From what I have heard you have to keep your speed up to stay on top of the loose stuff. I doubt I would try steering with the throttle up north. I agree with deadboy, maybe closer to home.

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I have done some searching on this topic but I can only find info for people riding GS's etc. What is the rule of thumb when it comes to reducing tire pressure when riding an RT or similar bike on gravel roads?

 

Thanks, Keith

The RT may be heavier but your trip load will bring you to near 900lbs.

 

I would hope you have metz880s or equal (no z rated rubber = soft). More resistant to sharp gravel.

 

All the advice is great, I would add; be careful of silt pockets. Wind blown loose sand in erosion pockets.

 

Good trip..

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I have done some searching on this topic but I can only find info for people riding GS's etc. What is the rule of thumb when it comes to reducing tire pressure when riding an RT or similar bike on gravel roads?

 

Thanks, Keith

The RT may be heavier but your trip load will bring you to near 900lbs.

 

I would hope you have metz880s or equal (no z rated rubber = soft). More resistant to sharp gravel.

 

All the advice is great, I would add; be careful of silt pockets. Wind blown loose sand in erosion pockets.

 

Good trip..

 

I decided on Avon Storm ST tires, just installed them last night. I do find one point fascinating... common wisdom is that if you look right in front of your bike you will do a face plant, better to look through the corner etc. But if you do not look at the road right in front of you when you are on gravel then you can not see the loose stuff you speak of.

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But if you do not look at the road right in front of you when you are on gravel then you can not see the loose stuff you speak of.

 

On gravel you need to look close in at your near focus area, plus ahead to see what's coming. Don't focus exclusively on the close though, which is easy to do. Remember consciously to scan far ahead and have your route planned in your head. If you don't do both, you can get in trouble and end up running too fast in to a sudden degraded road situation. Gravel is more tiring mentally because of this. I also suspect focusing primarily on the close and not on the far is a cause of many motorcycle gravel road crashes. If you can ride with another rider who is of your pace, it's nice to share lead because of the constant look ahead and look close, route planning, and such.

 

Because of this, I keep the windshield of my RT down a little more than normal, except when meeting trucks and rock spitting vehicles. Wear a face shield helmet, shield down always.

 

Don't get over confident. Over confidence has caused a lot of crashes in gravel. Ride at a pace ONLY AS FAR AS YOU CAN SEE! You may be going 60 mph on one super solid stretch, then immediately prior to the next curve or rise in the road, you'll be down to 30 mph. Don't ride with or be influenced by someone who rides at a pace that is uncomfortable for you. Listen to your self in terms of safety and don't let others determine your riding style.

 

I don't recommend 100 mph and sliding the rear. Rescue on bush roads is long in waiting, if qualified help arrives, and probably a painful ride in the back of a pickup for the distanace you are from the nearest major town. "Rescue 911" does not happen in the bush. Ride in a way knowing this is the case.

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I learned to ride, then rode from Fairbanks to Whitehorse as my first ride outside of the gravel pit I learned in, near Fairbanks, AK. At the time that road was all gravel from the Alaska border to Whitehorse. Tire pressure was the same for gravel or pavement. Keep loose and let the bike dance under you. Occasionally I'd crack rims on steep sided potholes. George, the BMW dealer in Fairbanks, was always on my case about these bent and broken rims (they are spokes on my R90/6) but bent and broken rims seem to be normal in AK. Haven't ridden my much newer R1100RT too much on gravel, only everytime I go riding. I have 13 miles of washboarded gravel just to get to the pavement. But same principal, same tire pressure, loose grips, and let the bike take it's path with minor guiding on the rider's part.

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motorman587

I am still in AK and just did the Haul Road this morining on my LT. I can tell you that I started the Haul Road with normal pressure and I was getting bumped around pretty bad until I took about 5 psi out the tires and the ride was great all the way up to Prudoe Bay, so I say "let the pressure out."

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  • 3 weeks later...

I just got back and I have to agree with John. I also ended up reducing the tire pressure by 4-5 lbs. Riding at the higher pressure the front tire would bounce around when going over larger pieces or in some cases single pieces of gravel. The lower pressure seemed to smooth that out. The gravel in the construction areas isn’t too bad as long as it has been packed down by the cars and trucks. What is a pain is the water they use to keep the dust down. Hitting pockets of virtually mud, which is where the water has sunk in more, can be a life altering experience. Your front tire dives to the soft side with no warning and bogs down. Having said that please keep in mind that my ride time on gravel before this trip was zero and that was a HUGE mistake. I am going to do a ride report called “ALCAN for the Noob” and will explain this more.

 

Oh, one more thing. The tip to lower the windshield was great! It opened up my field of vision right in front of the bike and helped to spot the trouble areas close in. Thanks for the advice and tips it sure did help!

 

Keith S

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