tire size

[Zombie Master]

1984 R100
Can you guys tell me what is the correct tire spec for snowflake wheels?

Is there a difference in specification between tire brands for these wheels?

[Kurt in S.A.]

This site says front 3.25x19 and rear 4.00x18.

http://www.bmbikes.co.uk/specpages/R100.htm

Kurt in S.A.

[Rob Frankham]

This site says front 3.25x19 and rear 4.00x18.

http://www.bmbikes.co.uk/specpages/R100.htm

Kurt in S.A.

Yup, that's the spec for everything from the 1969 R50/5 to the 1984 R100Rs with the exception of the R45/R65 models which have a
18" front wheel. Imperial size tyres are still available but some people who have gone with metric 'equivalents' find problems with rear wheel/ swing arm clearance dependant on tyre type.

Rob

[barryh]

1984 R100
Is there a difference in specification between tire brands for these wheels?

There are differences particularly if you go metric.

A 4.00 x`18 rear will typically be 671 mm diameter and have a mounted width around 110 -115 mm

110.90's will typically be 15-20 mm smaller in diameter and a similar width to the 4.00 so no rubbing problems on fitment but a small change in effective mph/1000 RPM.

120/90 will typically be a similar diameter to a 4.00 but up to 125 mm wide which can rub on the swinging arm.

If that isn't enough, some manufacturers seem to construct their 4.00 x 18 in the same mold as a 120/90 and just change the designated size to 4.00 so you find a 4.00 to be bigger than expected.

[Zombie Master]

Thanx

[lrz]

It's time for a new set,so I've been shopping.
Figured I'd getaway from metric Spitfires for a change this year...

In rears, it looks like Avon Roadrider no longer offers inch sizes and even the Metzeler Lasertec from MAX has gone metric ??


https://www.rockymountainatvmc.com/ti ... cle-tire-p

https://shop.maxbmw.com/fiche/DiagramsM ... d=07242017


Or am I missing something?

[jagarra]

Michelin makes them in inch sizes for the BMW https://www.bikebandit.com/tires-tubes/ ... 3?m=143994

[SteveD]

Michelin makes them in inch sizes for the BMW https://www.bikebandit.com/tires-tubes/ ... 3?m=143994

Excellent tyres Michelin but difficult to mount and seat. Be prepared for a tad more psi.....

[Rob Frankham]

Metzler lasertec and ME77 are still around in imperial sizes... in the UK at least. In fact, Max actually list them on their site...

https://shop.maxbmw.com/fiche/PartsDeta ... T_ME77REAR

https://shop.maxbmw.com/fiche/PartsDeta ... ASERTECH_F

Though to my eye, they look a bit on the expensive side. You may well get a better deal by going to a specialist tyre seller...

Rob

[lrz]

Michelin makes them in inch sizes for the BMW https://www.bikebandit.com/tires-tubes/ ... 3?m=143994

Those are tough to spoon.

Regarding MAX, it is also noteworthy to me that they've stopped offering Avon tyres; at least as per the /7 fiche.

If metric has become common, probably I'll stick with Spitfires since they are a known quantity.

I seem to recall inch sizes were readily available the last time I was shopping which,iirc,was Spring 2018...