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Discussion Starter · #1 ·
My friend OldOkie (who rarely posts) is having a bit of trouble finding exact size replacement tires for him BMW.



According to the factory manual:



Front: 3.25 x 19

Rear: 4.0 x 18



He wants to use Metzler Lasertech tires but he wants the right sizes when converted to the new metric equivalents.



Some idiot put a 110/90/18 on the rear, no wonder it handles a bit oddly but that's the way he got the bike and has ridden on it for years that way. The tires are 10 years old and of course showing some rubber deterioration so he's wisely going to replace them, he's even thinking about selling it as well as his GL650I, both of which are in almost factory perfect condition so if anyone's near Oklahoma and in the market let me know.
 

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Discussion Starter · #3 ·
Too late to call now, he worked all day then moved my bike up to his heated garage to put the final parts on it this weekend.



That would however explain the 110/90 on the rear. I don't know the exact year or model but I'll call tomorrow and find out.



If he does end up selling it I want at least one ride first but only with the new tires. If I recall he also needs to replace the valve stem seals which is a major pain as working on any BMW is. He's an engineer thus a stickler for accuracy and the only one I know around here that also has a stable full of Honda CX/GL projects in progress - much less even one.



If we tried to organize a CX/GL ride around here we'd probably be the only two unless a few came in from the surrounding states. I've got a nice ride planned out to a tiny out of the way state park that involves more twists and turns than you can imagine. The nice thing is for about $12/night you can have a large campsite with restrooms, showers, 120V power and since I can't very well strap my chainsaw on the back of the bike at least the forest ranger in charge of the place will bring you firewood on his ATV for $3 per large bundle.



Rare to find anyone there unless the Choctaw Indians are having a function in nearby Tuskahoma then it kind of fills up. Fishing and swimming are great but you can almost forget about your cell phone, radio or TV working from there as it's kind of buried in a valley in the middle of nowhere. http://www.outdoorsok.com/Oklahoma/Clayton
 

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Looks like the bike in question is a



1984 BMW R100RT



Found this.

http://www.webbikeworld.com/r100rs/bmw-r100rs.htm



BMW R100RS Tires: Tire sizes for the R100RS are the 3.25-19 front and 4.00-18 rear. Modern size replacements are 100/90-19 front and 120/90-18 rear, which will fit the '84 and probably other model years. Tires are available in these sizes from Avon (AM18 F/R); Bridgestone (BT45); Continental (Blitz, TK11/TK12 F/R); Metzeler (ME33 front and ME99A rear); Michelin (Macadam 50 & 50E). Metzeler recommends a 100/90-19 front and 4.00-18 rear. I use the Conti's on my '84 and they work great!
 

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For an R80BMW I highly recommend the ME33-V front and the ME88-H rear. I did 95K on my R80 until a lady wiped it out. You can figure 14-18K off a set of tires, with great stick.



I used that combo on my GL bikes until they quit making the ME88 in the size needed for the GL. They still make the tire for BMW air-heads though.



The ME33-V is a much better tire than the ME88 for rain, rain grooves and steel bridges and it wears out at the same rate as the ME88-H rear tire.
 

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Discussion Starter · #7 ·
Thanks, that's exactly what he's wanting to know. I'll call him tonight, he's been pretty busy at his office the past few days.
 

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Discussion Starter · #8 ·
You did nail the model #: BMW R100RT



He's just going to get the true 4.0 x 18 Metzler for the rear and whatever he found that matches for the 3.25x19 for the front.

Damn, those tires are expensive. He considered the Bridgestones since he uses them on his CX & GL but couldn't find the proper rear.
 

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You did nail the model #: BMW R100RT



He's just going to get the true 4.0 x 18 Metzler for the rear and whatever he found that matches for the 3.25x19 for the front.

Damn, those tires are expensive. He considered the Bridgestones since he uses them on his CX & GL but couldn't find the proper rear.


Here are some searches @ American Moto, most of them

will not work for his application:



Here is a 3.25X19 search:



http://www.americanmototire.com/cat...d=756&osCsid=7e40454a2c37150c5a1e1835fe59202b



And a 4.00X18 search:



http://www.americanmototire.com/cat...d=714&osCsid=7e40454a2c37150c5a1e1835fe59202b
 

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Thanks for the help, there is a lot of confusion about tire sizes.

The 3.25x19 front and the 4.00x18 rear will work for the BMW 1984 R100RT

and you have given me more places to shop for tires.

Now if I can get the darned thing started, don't want wait until

summer to ride it. There are times I wish I did not like that bike.
 

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What's the starting problem? Remember this new gas turns to crap pretty quickly so if you haven't ridden it in a while drain the carbs and start over.
 

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Discussion Starter · #12 ·
I know the bike and it's ridden often, see his posts in the happy new years thread.



If the valves are slightly misadjusted or the complicated ignition timing isn't exact a BMW will be very picky.
 

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I know the bike and it's ridden often, see his posts in the happy new years thread.



If the valves are slightly misadjusted or the complicated ignition timing isn't exact a BMW will be very picky.


Timing is super easy on a BMW. You take the front cover off, loosen two screws and turn the ignition on the front of the crank can until the timing marks line up properly. It is much easier than on than CX/GL.



The valves on an airhead Beemer are easier to set than on a CX/GL.



That said, the timing on the Hondas are pretty easy too, if you don't mount it 180 degrees off.



That all said, I will be riding my Honda after I quit riding my Beemer ...
 
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