150/70R17 Rear on an ST1100 ABSII

[jrp]

Hello fellow ST'ers,

I am soliciting opinions what affects could be expected (other than the indicated speed and slightly lower ride height) by running a 150/70R17 on a ST1100 ABSII in place of the stock 160/70R17. I used an online tire comparison tool and it gave me the following information:



This is the tire I am looking at: https://www.continental-tires.com/motorcycle/tires/motorcycle-tires/off-road-enduro/tkc-70-rocks

EDIT: Another one: https://powersports.kendatire.com/en-us/find-a-tire/motorcyclescooter/dual-sportadventure/big-block/

I am thinking of using this tire only for a 1000 mile segment of a larger trip where the road conditions can vary from pavement to gravel to dirt. I am still looking at front tires. I've no experience running tires other than stock size.

 

[Larry Fine]

The 0.6" diameter translates to a 0.3" height difference, which is easily compensated for with a rear suspension adjustment.

What matters more, perhaps, is the difference in width which, while proportionate, is also less than stock. This is all obvious.

I believe theory and motorcycling science would say that the narrower tire would quicken the steering, and be more nimble.

In my opinion, unless you had a way to instantly compare for any riding/handling difference, you'll probably never notice it.

 

[beemerphile]

Two things you will immediately notice with the shorter tire is that it is even more of a grunt than it already was to hoist it up on the centerstand - and that some of your cornering clearance went somewhere. What you may not notice (but should) is that the rear carrying capacity is diminished. The Bridgestone T31 I used for spec comparison went from a load range of 69 (716 lbs.) in 150 width to a load range of 73 (805 lbs.) in the 160 width.

Smart money says run the correct size. Motorcycles are designed from the tires up, and if you change them, you are now the motorcycle designer. You'd want to make sure you are qualified. You are picking around trying to guess the implications of changes that he already knows and your enjoyment of the motorcycle, and maybe even your safety, lie in the balance.

 

[paulcb]

I am thinking of using this tire only for a 1000 mile segment of a larger trip where the road conditions can vary from pavement to gravel to dirt. I am still looking at front tires. I've no experience running tires other than stock size.

For only this 1000 miles, and most likely not at any serious speed, I can't see any significant risk in using that tire. It would probably be just fine anywhere but the track, just use it as designed (not high speed cornering) and don't overload it. I say go for it.

 

[beemerphile]

For 1000 miles of gravel and dirt, just ride on. Any road that is so gnarly that a road tire won't traverse it, is probably too bad to be on with an ST because of weight and ground clearance . If the road is well graded, it ought to be passable with road tires.

My R1150R (a street bike with Metzeler Marathon road tires) went to Inuvik, NWT and Deadhorse, AK in heavy construction and rain). The trip was 13,800 mile and 2000 miles of it was unpaved - most of the unpaved was on the Dalton, Dempster, and Top-of-the-World Highways.

 

[dwalby]

It looks like that tire has an "S" speed rating, which will be fine for your intended gravel/dirt/slow usage, but won't be all that great at higher speeds on pavement. Many years ago a tire shop mounted an "S" rated rear tire on my friend's Suzuki GS1100 and he never noticed it. As a group of us tore through Sierra area twisties at high speeds he used up what looked like half of the tread within a couple hundred miles, I wouldn't have believed it was possible to wear a tire that fast if I didn't see it first hand.

And also as Beemerphile said, your weight rating is decreased by 100lbs, so make sure you'll have margin there.

The other question I'd have, is if mounting a dual-sport type tire onto a massive beast like the ST1100 provides any meaningful advantage over the standard tire anyway.

Anybody ever tried this??

 

[jrp]

Thanks for the feedback. I am tentively planning an Alaska trip next year, so tires are understandably on my mind. It was heartening to read Lee's response about the places the Metzler Marathons took him.

I would NOT be attempting anything beyond the difficulties of the Dempster or Dalton. My thinking is 'normal' road tires until Fairbanks and then switch them for the trip up to Deadhorse (or however far I went based on conditions). Upon return to Fairbanks, I would switch back to the 'normal' road tires. The accounts I have read is that you do not want normal road tires on the Dalton in the rain if you can avoid it.

Problem is, there is really nothing available in a rear tire size that is an enduro, adventure (call it want you want) type tire in a 160/70-17. I get that. That is why I was looking at a 150/70-17 which has the same aspect ratio. There are a few options available in the 120/70-18 size.

I did a search and it appears that the Metzeler ME 880 Marathons come in 120/70-18 for the front but they do not make a 160/70-17. Maybe I just should be looking to get a different bike or just cross the Dalton off my list, but I really would like to go on the ST1100.

Jeff

 

[Al st1100]

I have been looking to make that trip but on a lot of research I will pass. A break down would cost an arm and leg, let alone a spill. Conditions can change quickly. Road crud can cover the radiator when conditions get bad. My ST is shaky on gravel but not bad on packed dirt, with street tires. Its one road I would not be comfortable trying with an ST, too heavy.

 

[beemerphile]

The tire I ran was a ME880B Marathon in 160/70-17 size. It seems now that the only B spec is the ME888B. The ME888 is supposed to be a much longer life version of the tire and may do the entire trip.

Marathon ME888B

My front Marathon did the entire 13,800 miles, but the rear had to be renewed in Anchorage. As important (or maybe more) than traction is the puncture resistance of the tire body. This is where the B spec Marathons shine (and why they are a PITA to mount!). For logistical reasons, they tend to use local aggregate on the roads and that tends to be shale pieces. Think of riding on a bunch of Indian arrowheads. The only flats I had on either the Dempster or the Dalton were when my rear Marathon wore out and I could only find a Dunlop to replace it. After four flats in 400 miles with the new Dunlop, I put the worn-out Metzeler back on and rode it over the Top-of-the-world Highway to Tok and down to Anchorage for another ME880B.

I know of no ADV tires in 160/70-17, but instead of going down to the 150, there are lots of 170/60-17 tires in ADV tread because of the water-cooled BMW GS bikes using them. If I wanted to "tire up" an ST for Dalton, I'd be looking at a Heidenau K60 in 170/60-17 size for the rear. I've run this tire and it rivals the Marathon in cord toughness but has better tread for unpaved roads. Be careful on wet asphalt though because they can get slippery. I threw a bike with K60's down a steel diamondplate ferry loading ramp in the rain once in Quebec.

Obviously street tires (and street bikes) are not optimal for that duty, but they can be made to work with the right rider. One place where you will be challenged (regardless of tires) is when you have to cross the gravel windrows when passing a roadscraper. Weather and construction are also likely to pose challenges, the level of which cannot be determined in advance. For some riders at some times they are insurmountable. Other riders at other times have an easy go. However you manage to fall, picking the dead whale up requires help. Sounds like a real adventure. Pack as light as you can.

EDITED TO ADD: If you look at my bike in #5 above, it has been stripped as far as possible for the upper half of the Dalton. I left the pack luggage at a cabin I rented in Wiseman. I rode from Wiseman to Deadhorse and back to Wiseman in one (long) day. It rained pretty much the entire time. I would have not made it with the full pack load which looked (stupidly) like this...

 

[beemerphile]

I have been looking to make that trip but on a lot of research I will pass. A break down would cost an arm and leg,

i didn't have to call one, but I heard that a tow truck call is $1,000 and tomorrow.

let alone a spill.

Depends on the spill. I dumped mine for nothing and got some help to right it.

Conditions can change quickly. Road crud can cover the radiator when conditions get bad.

An important consideration on a water-cooled bike if you get into wet conditions. The calcium coats like concrete and is about that difficult to remove. The bike I took was air/oil cooled. I put screens over the oil-coolers and when they got blocked, I changed them. You can see them above the cylinders in this picture. The richest guy in Fairbanks may be the guy who owns the coin car wash in town.

...I would not be comfortable trying with an ST, too heavy.

Comfortable would not describe it. The two biggest things I learned from the trip was:

1) The bike was too heavy - especially after I packed everything I might possibly need onto it. Dumb.
2) Don't worry about the bears, worry about the mosquitos. I came home with a full can of bear spray and two empty bottles of DEET.

 

[jrp]

The tire I ran was a ME880B Marathon in 160/70-17 size. It seems now that the only B spec is the ME888B. The ME888 is supposed to be a much longer life version of the tire and may do the entire trip.

Marathon ME888B

My front Marathon did the entire 13,800 miles, but the rear had to be renewed in Anchorage. As important (or maybe more) than traction is the puncture resistance of the tire body. This is where the B spec Marathons shine (and why they are a PITA to mount!). For logistical reasons, they tend to use local aggregate on the roads and that tends to be shale pieces. Think of riding on a bunch of Indian arrowheads. The only flats I had on either the Dempster or the Dalton were when my rear Marathon wore out and I could only find a Dunlop to replace it. After four flats in 400 miles with the new Dunlop, I put the worn-out Metzeler back on and rode it over the Top-of-the-world Highway to Tok and down to Anchorage for another ME880B.

I know of no ADV tires in 160/70-17, but instead of going down to the 150, there are lots of 170/60-17 tires in ADV tread because of the water-cooled BMW GS bikes using them. If I wanted to "tire up" an ST for Dalton, I'd be looking at a Heidenau K60 in 170/60-17 size for the rear. I've run this tire and it rivals the Marathon in cord toughness but has better tread for unpaved roads. Be careful on wet asphalt though because they can get slippery. I threw a bike with K60's down a steel diamondplate ferry loading ramp in the rain once in Quebec.

Obviously street tires (and street bikes) are not optimal for that duty, but they can be made to work with the right rider. One place where you will be challenged (regardless of tires) is when you have to cross the gravel windrows when passing a roadscraper. Weather and construction are also likely to pose challenges, the level of which cannot be determined in advance. For some riders at some times they are insurmountable. Other riders at other times have an easy go. However you manage to fall, picking the dead whale up requires help. Sounds like a real adventure. Pack as light as you can.

EDITED TO ADD: If you look at my bike in #5 above, it has been stripped as far as possible for the upper half of the Dalton. I left the pack luggage at a cabin I rented in Wiseman. I rode from Wiseman to Deadhorse and back to Wiseman in one (long) day. It rained pretty much the entire time. I would have not made it with the full pack load which looked (stupidly) like this...

The Metzeler ME888 Ultra Marathon has the correct sizes for the ST. Is that the same tire as the ME888B?

The Heidenau K60 looks like an interesting option and I know it fits since you've used it on your ST.

I am starting to think that maybe it's not worth the hassle to take the ST. I can (and have) picked it up from a tip-over but that has been on pavement. Don't think I'd be able to get enough purchase to do it on a dirt road and definitely not a muddy road. Probably better to get a used KLR650 and prep it. Thanks for the tips on the Dalton; major props on making it to all those places on road tires. I'll have to give it some more thought. The K60 looks like a definite possibility.

 

[beemerphile]

The Metzeler ME888 Ultra Marathon has the correct sizes for the ST. Is that the same tire as the ME888B?

Marathon Ultra is just the name of the ME888 same as Marathon is the name for the ME880. The "B Spec" (also called "reinforced") is a bias ply tire where the R designations are radials. The B is a very different tire from the R (ME880 or ME888). No size is available both as a B and an R. The 160/70 is a B spec and the 170/60 is an R spec.

The Heidenau K60 looks like an interesting option and I know it fits since you've used it on your ST.

My experience with the tire (and the bike I threw down the ferry ramp) was not my ST. Sorry if I misled on that.

I am starting to think that maybe it's not worth the hassle to take the ST. I can (and have) picked it up from a tip-over but that has been on pavement. Don't think I'd be able to get enough purchase to do it on a dirt road and definitely not a muddy road.

The last mud road spill on my ST11 (a few weeks ago) took four oversized Georgia Boys to extricate the ST from the ditch...

Probably better to get a used KLR650 and prep it.

A much more practical choice for the ride. In addition to it being a difficult undertaking, the ride is very hard on the aesthetics of the machine - especially if you get a rainy trip. It will never be the same after the trip unless you take it down to the frame and clean and paint everything. Lots of bearings and seals will be shot. The rear suspension will probably return as a pogo stick. Brake calipers will need to be rebuilt. Here is a gallery of the work required to my R1150R after the trip to get it back in 100% shape...

https://beemerphile.smugmug.com/Motorcycles/Former/Leeta/LeetaRest

Thanks for the tips on the Dalton.

You're welcome. It was a wonderful experience. If you stop at the Artcic Circle and leave the top half of the Dalton alone, you won't be risking too much with a road bike. I saw several baggers, an old hippie on a chopper, and a guy on a Harley 3-wheeler at the Arctic Circle sign. On the Top-of-the-World Highway I saw a small woman on a Hayabusa. Yep. Street tires on all of them.

 

[bdalameda]

I think you should consider using a Shinko 705 - Adventure tire in 170/60/17. I have had good luck on and off road and they are a decent wearing tire. These tires are well proven in the adventure riding community. They are a good compromise for both road and dirt and handle well on the street and have really decent performance on the dirt. I would think this type of tire would work much better on the ST for the type of trip you are talking about.

705 Series Dual Sport Tire

The Shinko 705 has a versatile tread pattern that provides excellent wet and dry weather adhesion and smooth running on the highway.

www.shinkotireusa.com

 

[jrp]

Nice photo journal of the post-trip work! I really like the custom electrical setup. Didn't know those BMW engines had a dry clutch. One look at all that work is making the KLR look better and better.

Marathon Ultra is just the name of the ME888 same as Marathon is the name for the ME880. The "B Spec" (also called "reinforced") is a bias ply tire where the R designations are radials. The B is a very different tire from the R (ME880 or ME888). No size is available both as a B and an R. The 160/70 is a B spec and the 170/60 is an R spec.



My experience with the tire (and the bike I threw down the ferry ramp) was not my ST. Sorry if I misled on that.



The last mud road spill on my ST11 (a few weeks ago) took four oversized Georgia Boys to extricate the ST from the ditch...




A much more practical choice for the ride. In addition to it being a difficult undertaking, the ride is very hard on the aesthetics of the machine - especially if you get a rainy trip. It will never be the same after the trip unless you take it down to the frame and clean and paint everything. Lots of bearings and seals will be shot. The rear suspension will probably return as a pogo stick. Brake calipers will need to be rebuilt. Here is a gallery of the work required to my R1150R after the trip to get it back in 100% shape...

https://beemerphile.smugmug.com/Motorcycles/Former/Leeta/LeetaRest



You're welcome. It was a wonderful experience. If you stop at the Artcic Circle and leave the top half of the Dalton alone, you won't be risking too much with a road bike. I saw several baggers, an old hippie on a chopper, and a guy on a Harley 3-wheeler at the Arctic Circle sign. On the Top-of-the-World Highway I saw a small woman on a Hayabusa. Yep. Street tires on all of them.

 

[beemerphile]

Nice photo journal of the post-trip work! I really like the custom electrical setup. Didn't know those BMW engines had a dry clutch. One look at all that work is making the KLR look better and better.

BMW clutches were dry from 1923 until 2013 for the R bikes.