tire size questions / oil slinger question

[chwood4]

I want to replace the tires on a 68 R60/US and 71 60/5 The /5 currently has a Metzler Lazer 3.50-19 on the front and a Metzler 99A 4.00-18 on the rear. It looks appears I can get Heidenau for both tires in exactly the same sizes. The rear tire on the /2 is currently a Metzler 4.00-18, so no problem. However the front tire is a Metzler ME77 with the following size designation 100/90 - 18.55. I am not sure how this would correlate to the 3.50 -19. Did BMW make a 18 1/2 inch wheel?? Has anyone had any experience with the Heidenau brand..They are a new one for me?

I am going to have both machines receive a new clutch / pressure plate and thought I might jump in and have the oil slinger cleaned while it is in the shop. Can anyone give me a rough idea as to the incremental cost of this service? Many thanks

 

[20774]

Lots of things going on here...both an Airhead and a vintage bike...which have different forums. Let's see what we can do.

What is the number 18.55? For metric tires, the 100 means the width in mm while the 90 means that the height is 90% of the width. Inch-size tires are "round"...no profile...metric tires has the profile. I run IRC GS-11s on front/back of my R69S...4.00 in the rear and 3.50 in the front. There are 3.5x18 tires out there if you look. Vech at Benchmark Works sells Heidenau...he likes them so they should be a good tire.

As for the slingers, to have it done by another shop, and likely have all of the internals changed for good measure, you're probably looking at north of $1000. Depending on who does the work, you can help yourself out by doing some work yourself, at least in terms of prepping the block. If the top end needs work, too, you're beginning to approach $2000 to 2500.

Clutches are fairly straight forward...consists of pulling back the swingarm, pulling the transmission, remove bad clutch part, insert good clutch parts, and reverse the disassembly. There are some tricky steps and procedures along the way, but generally not that difficult. It can get more difficult if, once inside, you see that you're leaking oil either at the tranny input seal of engine rear main seal. You'll find out when you see oily residue when the transmission is pulled back.