Uneven front tire wear on 1998 R1100RT

The left side tread on the front tire of my 1998 R1100RT is wearing unevenly compared with the right hand side, the angled tread sections are developing a cupped wear patten to the front and this causes some vibration. It has been suggested that I inflate over 32psi (single rider tire pressure in the operator's manual) to 36psi, any suggestions would be appreciated from other riders or BMW mechanics. The last tire wore the same way and was replaced when vibration became annoying.

Same deal with my '01 1100S. Dealer says it's normal.

I ride an R1100RT. I have seen the front tire left side wear more quickly than the right side on occation, but for me it has not been a real problem or a cause of vibration. I always assumed that it is because of the slope on the highways. I always run 36 psi front and 42 psi rear, regardless of load.

Edit to add: I generally run Metzler Z6 tires on my RT.

You didn't say which tire you were running. I have a Battlaxe BT020 on the front right now which has tread blocks. The new BT021 has snaky sipes and no blocks. It is my experience that the blocks cup because of the way they bend as they grip.
As far as the left side wear goes, look here.

www.rattlebars.com/valkfaq/tirewear/.

Very interesting article.

Very common observation. Seems to happen with all brands of tyres. Slightly higher pressures may help. Don't worry about it - TADT!

I think there are two reasons the left wears more than the right. As has been mentioned, the crown of the road is one reason. The other reason is that we tend to take left hand turns more aggressively than we do right hand turns. I think it is natural as we are far more comfortable leaning left than we are leaning right.

I also always keep the front at 36 and the rear at 42 on all of my bikes and have never had an uneven tire wear problem.

Ken

TheRoss said:

I ride an R1100RT...... I always assumed that it is because of the slope on the highways.

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Well I say BS on the slope of the road. If it were true then every car, truck, bicycle, wagon, scooter, etc would have wear issues on the "front left". I have 3 Honda motorcycles and have put a ton of miles on them and they don't wear like that, Hmmmmmm..... No my friends this is a BMW issue, could be the torque from the motor wanting to twist the front, could just be some sort of alignment issue, who knows. I know it's not the "slope of the road".

OK I'll go back to my RT where it wears weird on the left side of the front tire and thats the way it is and I deal with it...

it's a MUCH observed phenomenon, and MUCH discussed in earlier threads ("search function" is a great tool, btw!).
The most accepted analysis is neither crown of road, nor riders being more aggressive turning to left than to right (how would you even come up with that one? I'm more aggressive in ALL corners! and many I know prefer rights to lefts, as they are turning away from oncoming traffic, and feel more confident in that direction). left hand turns in the US are slightly longer than are right handers, leading to increased wear due to the greater mileage that the left side side of the tire covers. It's a small amount per corner/curve, but adds up over the life of the tire.

The bike is heavier right of center than left. Transmission parts, most of the swingarm, final drive, etc. So we get "pulling to the right" threads and "front tire wear on the left threads. And despite the skeptics loud declarations, the road crown is a contributing factor too.

The two factors together cause Oilhead (and classic K) riders to generally maintain some slight steer to the left all the time in order to go straight down the road. You can mitigate the weight issue by loading the left saddlebag heavier than the right saddlebag. About 10 to 15 pounds heavier is the conventional wisdom.

RT riders who don't believe me need to gather up an assistant and go out to their bikes with a plumb bob. With the bike absolutely plumb, sitting on its wheels, let go. Watch it fall over to the right every time. If it doesn't you didn't have it plumb. Gravity wins every time, unless the wind is blowing. I assume no liability for damage. The assistant is supposed to catch it.

PGlaves said:

The bike is heavier right of center than left. Transmission parts, most of the swingarm, final drive, etc. So we get "pulling to the right" threads and "front tire wear on the left threads. And despite the skeptics loud declarations, the road crown is a contributing factor too.

The two factors together cause Oilhead (and classic K) riders to generally maintain some slight steer to the left all the time in order to go straight down the road. You can mitigate the weight issue by loading the left saddlebag heavier than the right saddlebag. About 10 to 15 pounds heavier is the conventional wisdom.

RT riders who don't believe me need to gather up an assistant and go out to their bikes with a plumb bob. With the bike absolutely plumb, sitting on its wheels, let go. Watch it fall over to the right every time. If it doesn't you didn't have it plumb. Gravity wins every time, unless the wind is blowing. I assume no liability for damage. The assistant is supposed to catch it.

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My experience matches Paul's, except I check it by lifting my hands off the bars while underway (with Throtlemeister engaged), which also takes into account the boxer engine's tendancy to twist the bike to the right. Regardless of the reason the bike pulls to the right (it also pulled to the right on surfaces sloped to the left!), the only way to correct is to shift wieght (rider and/or load) or countersteer (the phyisics and mechanics of steering are treated very thoroughly in "Proficient Motorcycling" by David Hough), which will scub the left side of the tire. I check tracking on a regular basis. If it pulls I shift my butt. I've learned to pack in a way that compensates, and after 3 Pilot Roads and 1 Metzler, which started to show flats on both sides at 2 - 3K, I switched to Avon Storm. After 12K I can't see or feel any flats or cupping on either side.

I landed on the weight thing when the pull got worse after removing the radio. I weighed the radio, 6 pounds, and moved 6 pounds of tools up there from under the seat and top box. That helped, but I still feel the pull when riding w no or empty cases. Even if I am FoS and it is the crown of the road, I'm enjoying longer tire life and MUCH improved low speed handling through the entire life of the tire.

ima4nr said:

I do agree with this, but insist it is NOT unique to BMWs.

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I never said it was unique to BMWs. It is a fact on any bike which has asymetric weight - that is - weight not perfectly balanced across the centerline of the two contact patches.

The bike will fall to and pull to the heavy side.

Slope of the road, in the US, "may" be a very slight contributor to the isse, but I doubt it really. Turning left versus turning right I feel has absolutely nothing to do with it.

The older R1100 and R1150 series oilheads, like my 94 R1100RS are heavily right side weighted. If anyone has ever removed the fuel tank from an early RS or RT oilhead it becomes very obvious that the majority of the fuel weight is to the right side of the bike. And as Paul Glaves said many other major parts are on the right side of the bike. Also, many of us load the right saddlebag heavier than the left, because the right bag is "higher" when on the sidestand.

The result of this right-side bias is we are CONSTANTLY, slightly pressing more on the left grip than on the right grip. This I know for certain, because in the 138k miles on my bike, my left wrist/hand cramps up more than my right hand ever does, yet the right hand is the one gripping the throttle to keep it open. My left hand ALWAYS gets sore and numb moreso than my right hand.

Other factors that contribute to tire wear, underinflation, crapped out front shock,(this I know for certain because my front tire wear is much BETTER sine I installed a new Wilbers shock on the front), any play in the front ball joints, unbalanced tire/wheel assembly. Other than that, its just that the older oilheads have a heavy right side weight bias. I would bet that anyone riding an older R1100RTP does not report the same tire wear, because on that bike the battery is on the left side to counteract the fuel weight to the right. Also, I have heard that RTPs do not exhibit the same drift to the right tracking issue.

Left side tire wear is common on all brands of bikes ridden in the US. If you get on other threads you will find this same question. Some bikes are worse than others. Another contributing factor is, given that we make an equal number of right and left turns there will be more mileage on the left side than the right. A left turn has a longer length than a right turn.

Ralph Sims

Our Horizon

BUDDINGGEEZER said:

Left side tire wear is common on all brands of bikes ridden in the US. If you get on other threads you will find this same question. Some bikes are worse than others. Another contributing factor is, given that we make an equal number of right and left turns there will be more mileage on the left side than the right. A left turn has a longer length than a right turn.

Ralph Sims

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Yes, this is an old thread. But there is one thing I'm surprised nobody mentioned (which I'll offer in a moment...).

First of all, reading this article www.rattlebars.com/valkfaq/tirewear will prove enlightening (which apparently Ralph has done, because he nails it...). The brand of bike, weight distribution and road crown are all micro issues at best.

We all know that the two major factors with tire wear are distance and aggressive riding (more scuffing). Since we drive on the right side of the road (US) the radius will always be longer with left turns than right (more time leaning on the left side of the tire equals greater wear). Without doing the math, even 10% greater distance would really add up. Over the life of the tire, the left side could look like it has an extra 1,000 miles on it, which is exactly what we are seeing.

And that is just the distance factor. Now let's look at the aggressive factor:

Safety instructors always preach "Don't over-run your horizon..." (sight distance down the road). From the right side of the road, a left turn offers a much longer "sight distance". And if we can see that no obstacles exist, what do we do? We get on the throttle, lean in, and enjoy an exhilarating turn! So, not only are we going a longer distance, we are doing it more aggressively! That, my friends is left side tire wear.

Conversely, right turns typically have a very short horizon (often blind). So those interested in keep their anatomy intact will approach with less speed until they can determine there are no fallen trees, deer, or stalled semi's just around the corner. Therefore, right turns are not only shorter, but are taken less aggressively (less scuffing), resulting in much less wear on the right side than the left.

There are those that say they are just as aggressive in both directions - on a race track, that would be true. But on a winding mountain road, throwing your bike into a blind right turn with reckless abandon could have dire consequences. Anybody who has been riding a while, and is giving their technique an honest evaluation, would recognize they shed more speed going into a right turn.

Riders in the UK, Australia or India, who drive on the left side of the road, would report right side tire wear.

Jim

As Paul said it could be that your bike has more weight on the right side with a pull to the right tendency, which you unknowingly compensate for with slight left pressure. I fixed mine with 10lbs. Lead in the glove box. http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=808495&page=7. Look about halfway down the page.

I have a '99 RT and ride in Arkansas where we have lots of left and right curves. I had the cupping problem (both sides) until I bumped the front pressure up to 40--I know the book says 36 max. I have been running Bridgestone T-30's with good luck for wear as compared to the Metzlers. I know the MEZ 8's are a stickier tire for more aggressive riders, but I opt for more mileage. I mount and balance my own, and have found that the B/S only require a small amount of balancer weight compared to others--and we are limited with an 18" rear for sizes that match. I just spooned on a set of T-30 EVO's which have a stiffer sidewall and will see how they compare. As suggested, I'm sure the shocks play a big part, and that will be my next addition soon.

Worn OE shocks will make cupping worse.
Virtually eliminated front cupping once I switched to new Ohlins.

GSAddict said:

Worn OE shocks will make cupping worse.
Virtually eliminated front cupping once I switched to new Ohlins.

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Ditto.

More Time on Left Side

roger 04 rt said:

As Paul said it could be that your bike has more weight on the right side with a pull to the right tendency, which you unknowingly compensate for with slight left pressure. I fixed mine with 10lbs. Lead in the glove box. http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=808495&page=7. Look about halfway down the page.

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Roger,
That is certainly some interesting analysis (link). I admire your inquiring mind. So, let's say that slightly more left steering inputs were applied to compensate for a right lean bias. Wouldn't that pale in comparison to a left turn twice the distance of a right turn?



(Illustration credit: Chet Walters)

roger 04 rt said:

As Paul said it could be that your bike has more weight on the right side with a pull to the right tendency, which you unknowingly compensate for with slight left pressure. I fixed mine with 10lbs. Lead in the glove box. http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=808495&page=7. Look about halfway down the page.

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Good one Roger! Only a fisherman or Burt Munroe would come up with that fix!