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Author Topic: Tire sizes!!!!  (Read 2657 times)

Offline Julio A.

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Tire sizes!!!!
« on: April 15, 2011, 05:10:03 AM »
My Tires are called for replacement already.

The User manual called for a 3.25 S 18 for the front and a 4.00 S 18 for the rear.

As the selection of tires for this bike here is pretty limited, I was only able to find a pair of metzeler lasertec tires. But it is in a different measurement.

The measurement was 90/90 - 18 front and 120/90 - 18 rear.

I'm a little worried in buying a possibly different size since the tire I'm using right now is in the correct measurement yet it barely clears both the swing arm.
« Last Edit: April 15, 2011, 05:18:55 AM by JAlarcon »
Julio Alarcon
1981 R65
1976 R90/6
2001 R1150 GS/ADV
2015 TR650

bruce_launceston

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Re: Tire sizes!!!!
« Reply #1 on: April 15, 2011, 05:55:13 AM »
Hi Julio, I run 100/90 on the front and a 110/90 on the rear. Most 120/90 rears are too tight although some will squeeze in. See if you can swap it for a 110.

Technically a 4.00 (inch) would be a 102/90 (mm) and a 3.25 would be a 81/90.

I find the Bridgestone BT45's excellent if you can find them.

Offline Julio A.

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Re: Tire sizes!!!!
« Reply #2 on: April 15, 2011, 08:00:43 AM »
Wow, thanks! I found the info really helpful. I'll give the Bridgestones a try. Hopefully I'll find a pair. They're a little cheaper than Metzelers too!
Julio Alarcon
1981 R65
1976 R90/6
2001 R1150 GS/ADV
2015 TR650

Offline Bob_Roller

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Re: Tire sizes!!!!
« Reply #3 on: April 15, 2011, 08:09:27 AM »
The 120 rear tires can be a bit of a hassle to get the wheel/tire on and off the bike .

You need to deflate the tire before attempting to remove the wheel .

'81 R65
'82 R65 LS
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!

Offline Julio A.

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Re: Tire sizes!!!!
« Reply #4 on: April 15, 2011, 11:52:46 AM »
Just out of curiosity, between the 90/90 and the 100/90 front tires that both fit the R65, is there any significant difference in regard to feel, cornering and other stuff?
Julio Alarcon
1981 R65
1976 R90/6
2001 R1150 GS/ADV
2015 TR650

tvrla

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Re: Tire sizes!!!!
« Reply #5 on: April 15, 2011, 12:09:25 PM »
The 90/90 looks real small while the 100/90 looks right, and comparable to the 3.25. It should handle just fine though. The larger bikes take the 100/90 x 19 - some friends have accidentally used the 90/90 and they rode just fine.

Offline montmil

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Re: Tire sizes!!!!
« Reply #6 on: April 15, 2011, 05:32:03 PM »
I like the way my '81 R65 turns in on the corners. It's a 100/90 Bridgestone Spitfire. 110/90 Spitfire on the rear. The Spitfires are a wee bit more economical than the BT45s. Both excellent tire values. Plus, the bike looks pretty racy with these sizes mounted.

Monte
Monte Miller
Denton, TEXAS
1978 BMW R100S
1981 BMW R65
1983 BMW R65
1995 Triumph Trophy
1986 VW Cabriolet

Offline Bob_Roller

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Re: Tire sizes!!!!
« Reply #7 on: April 15, 2011, 06:00:23 PM »
An option that you do have, if you can't find a rear tire narrower than a 120 width, is to replace the top hat/ compression spacers that stick out of the wheel bearing seals .

You can get one that is just a bit under 4 mm .

Install it on the side of the wheel that goes up against the final drive .

You will also need a thinner washer under the axle nut .

Make sure that you have at least one thread protruding through the nut when you get done tightening it up .
'81 R65
'82 R65 LS
'84 R65 LS
'87 Moto Guzzi V65 Lario
'02 R1150R
Riding all year long since 1993 .
I'll give up my R65, when they pry my cold dead hands from the handlebars !!!!!

Offline Julio A.

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Re: Tire sizes!!!!
« Reply #8 on: April 16, 2011, 02:19:50 AM »
Unfortunately, There is no Bridgestone BT45's or Spitfires available here. The Metzeler Lasertecs weren't also available in the correct size.

I'm settling for a pair of Pirelli City demons as these are the only ones available in the correct bias sizes.

I appreciate all the input guys, many thanks!  :)

Julio Alarcon
1981 R65
1976 R90/6
2001 R1150 GS/ADV
2015 TR650

Offline Rob Valdez 79 R65

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Re: Tire sizes!!!!
« Reply #9 on: April 16, 2011, 03:23:43 AM »
100/90 front and 110/90 rear for me.  I am very happy with the way the bike handles.

(Bridgestone Spitfires, but that is irrelevant for you, Julio.)

Offline Barry

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Re: Tire sizes!!!!
« Reply #10 on: April 16, 2011, 01:06:57 PM »
Quote
I'm settling for a pair of Pirelli City demons as these are the only ones available in the correct bias sizes.  

Pirelli City Demons tires are available in 4.00 x 18 I fitted one a couple of years back.  It was easy to fit on the rim (compared to a Metzeler) and slides in past the brakes shoes fairly easy. Wears well too. Hard to give a definitive view of the handling as any new tire is a revelation after an old worn squared off one.
« Last Edit: April 16, 2011, 01:07:34 PM by bhodgson »
Barry Cheshire, England 79 R45

raypond

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Re: Tire sizes!!!!
« Reply #11 on: April 17, 2011, 02:24:53 AM »
I reckon stick to the original tyre sizes, especially on the front. The PO of my bike had put 100/90s on the front and so for a while I just replaced them with the same. I then put on the specified 90/90 and it transformed the handling - lighter, quicker, goes around corners better. I did use BT45s but seem not be able to get them here in Oz anymore. I currently have Michelin Road Activ  tyres front and rear and I'm very happy with them. Too early yet to know how they wear.

Offline Justin B.

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Re: Tire sizes!!!!
« Reply #12 on: April 17, 2011, 08:36:28 PM »
I am running 90/90-18 on the front and it gives nimble steering where the 100/90 will have some "understeer".  The newer monoshock Airheads specified 90/90-18 front and 90/120-18 rear.  I have that combination on the Junkyard Dawg and it handles great.
Justin B.

2004 BMW R1150RT
1981 R100RT - Summer bike, NEKKID!!!

rwait

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Re: Tire sizes!!!!
« Reply #13 on: April 24, 2011, 09:04:16 PM »
Also consider the relatively new (been out maybe a year or so) Continental Go's.  I'm on my second set and have really been happy with them.  They come in sizes to fit the R65.  Check out this link - http://www.tiresunlimited.com/ALL%20TIRES/Continental/continental_conti_GO.htm.  I ordered both sets through this company in Ohio and have been very happy with the price and service I received.

RW