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-   BMW R1100S / R1200S Tech Forum (http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/)
-   -   R1100s tire size (http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/413928-r1100s-tire-size.html)

TestaRosa 06-09-2008 09:38 PM

R1100s tire size
 
I currently am running the stock 170 tire on my 2004 R1100s and my question is on sizing. I know the 180/55 is an optional tire and Technically is the same size with just different aspect ratios. Which tire will lie into a corner easier and quicker(better handling) or is there another size recomendation to go with.

twodear 06-10-2008 12:26 AM

180 = 6
 
I'm assuming you have a 5.5in rim? I know some here have fit a 180 section tyre onto a 5.5 in rim, but I'm not sure why. I've never tried a 180 section on my 5.5, but I've heard others that have tried it say that in general, it is a disadvantage. A 180 needs a 6in rim to work best.

If you try it. let us know how it worked out?

jduke 06-10-2008 04:47 AM

A 5" rim will take either a 160 or 170. The wider, 5.5" takes the 180.

Bob Hancock 06-10-2008 04:48 AM

I don't think that's right, twodear. I think most R11S's come with the 5" rim and the 170/60 tire. To put the 180/55 on you need a 5.5" rim. The 6" rim on my R12S takes the 190/50.
A pretty good and simple explanation of what wider tires does to handling is in the latest Cycle World. As has been explained on this forum many times, the wider tire slows the steering and so you need to make other adjustments to quicken it back to where it should be. I think BMW did that with the sport shock package when they offered the 5.5" rim. Our racers may pitch in here as they are always changing something so should know from experience. I've only used the tire size appropriate to the rim size.
Anyway.....check your wheel size and tire it appropriately. My 2 cents.

markjenn 06-10-2008 06:35 AM

I think Bob has got it right. On the narrower rim, you really don't want to go wider than 170. On the wider rim, 180 is fine, but the bike probably handles better with the 170. What was stock tire fitment on the R1100S 5.5" rim?

- Mark

Bob Hancock 06-10-2008 06:38 AM

Quote:

Originally Posted by markjenn (Post 3994339)
What was stock tire fitment on the R1100S 5.5" rim?

- Mark

180/55 on my '04 BCPrep.

jduke 06-10-2008 07:04 AM

Same here.

markjenn 06-10-2008 08:24 AM

.... then I'd stick with the 170 on the 5.0" and the 180 on the 5.5" as optimal.

- Mark

Guest24 06-10-2008 08:53 AM

Yep, Bob is correct. Using a wider tire on a narrow rim increases the arc thereby reducing the contact patch. This comment is only worth a penny; but, the copper content in a penny is now worth more than a penny.:D

jduke 06-10-2008 08:58 AM

I also heard that it now costs more to make a nickel than it's worth....
How about recycled aluminum (al-u-many-um to some) for ALL coins?

roger albert 06-10-2008 09:15 AM

> .... then I'd stick with the 170 on the 5.0" and the 180 on the 5.5" as optimal.

Not much else makes sense for bike's of this weight. Older, lighter, conservative geometry Ducatis and Japanese sportbikes seemed to do well with 170s on a 5.5, but it doesn't make much sense on our bikes.

(What I really like on an 11S is a 190 on a light 5.75, but that takes a more-than-just-pocketchange investment.)

tm1100s 06-10-2008 09:22 AM

Any tire manufacturer will have all the specs and recommended rim widths for their tires. If you can't find it online, call them and they will talk your ear off about fitment. If I can find the chart, it was Michelin or Pirelli that you could look up the tire and it would give you the optimum rim width for that tire and a secondary choice if you wanted. Generally, 5 inch a 170, 5.5 inch a 180 and 6.0 inch a 190, generally. But any tire company tells you this. If you choose the non-optimum tire for the rim you will change the profile and you accept the handling differences. I found a good example of this with my Aprilia Tuono. It has a 6 inch rear rim and came with a 190/50 tire. Many have changed to the 180/55 to improve handling and the Michelin chart shows this change as an option. I changed to the 180 for a while and found that I had a little front end wobble entering turns at almost any speed. Might have been able to tune it out with suspension adjustments but going back to the 190 fixed the problem. Others didn't have the problem at all.

Thing is, the tire guys do more R&D then we could ever do.

By the way, I have a brand new Pilot Power 170/60ZR17R that I got for Cyndy's 5.0 inch rim before we added the 5.5 PVMs.
Make an offer and I ship it.

tm1100s 06-10-2008 10:00 AM

Hey, Bubba. You old enough to remember when pennies WERE made of copper, too?

No more.

Guest24 06-10-2008 10:06 AM

Quote:

Originally Posted by tm1100s (Post 3994715)
Hey, Bubba. You old enough to remember when pennies WERE made of copper, too?

No more.

I still have some steel pennies from WWII:eek:

EZ-RIDER 06-10-2008 10:24 AM

Quote:

Originally Posted by roger albert (Post 3994633)
> .... then I'd stick with the 170 on the 5.0" and the 180 on the 5.5" as optimal.

Not much else makes sense for bike's of this weight. Older, lighter, conservative geometry Ducatis and Japanese sportbikes seemed to do well with 170s on a 5.5, but it doesn't make much sense on our bikes.

(What I really like on an 11S is a 190 on a light 5.75, but that takes a more-than-just-pocketchange investment.)

Hey Roger;

What size 190 on a light 5.75 ??????

roger albert 06-10-2008 10:31 AM

50 iirc

twodear 06-10-2008 01:01 PM

Quote:

Originally Posted by Bob Hancock (Post 3994164)
I don't think that's right, twodear. I think most R11S's come with the 5" rim and the 170/60 tire. To put the 180/55 on you need a 5.5" rim. The 6" rim on my R12S takes the 190/50.
A pretty good and simple explanation of what wider tires does to handling is in the latest Cycle World. As has been explained on this forum many times, the wider tire slows the steering and so you need to make other adjustments to quicken it back to where it should be. I think BMW did that with the sport shock package when they offered the 5.5" rim. Our racers may pitch in here as they are always changing something so should know from experience. I've only used the tire size appropriate to the rim size.
Anyway.....check your wheel size and tire it appropriately. My 2 cents.

Yep, thanks for setting me right Bob; 5 = 170, 5.5 = 180 and 6 = 190. I'm about 1050km away from my bike for another week and having nothing to look at I relied on memory - it is always a mistake (but I keep forgetting that).

TestaRosa 06-10-2008 05:51 PM

The rear wheel is 5.5 edge to edge. It has the 170 on there. Im just questioning if the 180 handles better or worse in the corners than the 170. I am leaning towards leaving everything the same and just going with a stickier tire composition. The strada's feel a little slick towards the edge even warmed up.

tim22 06-10-2008 06:17 PM

I'm not as "learned" as some of the others on this site, but a wider tire will prevent your bike from cornering as easily--it will feel a little heavier on lean-in. Many people seem to want a fatter rear tire because it looks cool (and I'm not accusing you of this TestaRosa--I know your concern IS handling), but the manufacturer knows best (usually?) and for the most part, the size tires the bike was designed for are best in all regards (or are the best compromise).

Okay, go ahead everybody. Shoot holes in my post and tell me how stupid I am.

Tim

wswartzwel 06-10-2008 06:57 PM

+1


On the post

Not on how stupid you are. :)


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