1986 R80RT- wrong size tire on it? opinions on Dunlop 404 vs Metzler ME88?

[tallcanuck]

specs on web say rear tire size for bike is 120/90-18R​

On the bike now previous owner has 110/90-18 Dunlop 404
Is that much of a difference in size? ie wrong size?

Also the Dunlop 404 seems ok but I read great things about the Metzeler ME88 120/90-18R.
I weigh 250lbs if that matters
Any opinions?

Thank you!

 

[20774]

The specs on this site say 120/90-18 is the right tire. Use the right tire size and proper inflation, and you should be OK. The max permissible weight given on this site suggests that at 950 lbs gross weight it acceptable.

BMW R80RT Monolever

The ultimate BMW motorcycle information pages

bmbikes.bmw-club.org.uk

 

[pauls1150]

The ME88 has not been made for a while (as far as I know ); if you find a "new old stock" one, check the date on the sidewall, as it may not be "as safe" as a newer tire. Others in that family are the ME880 and 888, which are both decent rubber for heavy touring bikes, but not the "best handling" for sporty riding. OK on grooves & bridges.
As far as the sizing goes, a 120 is a bit higher and wider that a 110.
Your weight isn't an issue, but never under-inflate a tire; that kills it faster by internal heating caused by wiggle of the innards.

 

[tallcanuck]

Thanks to you both!!

 

[ebeeby]

What is the consensus proper tire pressure for an R75/5?

 

[20774]

What is the consensus proper tire pressure for an R75/5?

Consensus! Ha!! You asked something like this 4 years ago!! I know we have this discussion from time to time, right after what oil to use!! Anyway, I've been running 31/32 front and 36 rear. Far from a consensus, but it works for me.

 

[PGlaves]

Try for pressures that cause a 10% pressure rise from cold to hot; say parked overnight is cold and after a 30 minute ride is hot. This will vary with the load and other factors so your answer may not be my answer.

 

[20774]

I remember the 10% rule from way back. My guess it doesn't work so well as we've gone to stiffer sidewalls which don't flex as much and don't generate as much heat and/or rise in pressure. I even tried it on a Dunlop Elite II rear tire about 20 years ago. Over the course of a month, I rode the same route out/back and took pressure readings before/after. I found that in order to get the 10% increase I would have to go outside the cold inflation temperature printed on the sidewall.

 

[kbasa]

Conti ClassicAttacks. I've got them on my R100CS and they're radials. They are, without a doubt, the best tire I've ever run in 45 years on airheads.