Tire widths on an RS - Page 2

fosterb · 11-20-2012, 06:20 AM

Quote:

Originally Posted by Jon-Lars

Stock tire width works best for a stock bike. Putting on a wider tire for the sake of appearance is pointless.

However, if you modify the engine to increase the horsepower, a wider tire works better to apply power to the road.

Wider rims can be laced on with a greater offset in order to clear the swingarm. Installation may require removing the rear drive entirely.

It works for me. I have a 130/80 on my R90S. Using an 18" front wheel helped with the turning.

we need more details on the 90 pls! and pics!!

Jon-Lars · 11-20-2012, 04:58 PM

headtube · 11-20-2012, 06:31 PM

Hmm... what sort of clearance do you have on that 130? Didn't think it was possible.

Jon-Lars · 11-20-2012, 06:48 PM

Buchanan built the wheels on this one, using shouldered Akront WM3-18 front and WM5-18 rear rims.

The rear rim was laced offset 12mm. This provides clearance from the big-tube swingarm.

Because the tires are wide, there is plenty of "patch alignment".

fosterb · 11-21-2012, 10:11 PM

you got a build report somewhere? need some more info on that scoot, she looks beautiful!

chasbmw · 11-22-2012, 02:03 AM

Both my airheads were greatly improved when I fitted a pair of the new Michelin pilot series tyres that are properly sized to be 3.25 and 4.00. Handling was much quicker AND more stable that the original BT45s. This is a good combination, in the wet or dry.

I found that my nominal 4.00 BT45 was in actually 118mm in width, so nearly a 120.

On your bike a 120 should fit with a bit of grunt in fitting it, if it rubs on the swinging arm there used to be a spacer that could be fitted to the hub to move the wheel away from the swinging arm.

Darryl's bmw · 11-23-2012, 06:09 AM

There is a spacer you can get that moves the rear wheel over about 3/16 over to the left to have the tire clear the swingarm..

Back in the racing days they ran much wider tires with a very large offset.

They even compensated with an offset for the swingarm in the frame but it could be hard on the u-joint.

Wirespokes · 11-24-2012, 07:52 AM

I doubt the small offset to the side would make any difference to the ujoint! They're made to handle offsets, up and down, so what difference would a little to the side make? They, in fact, don't do well with no movement; it's the extremes you want to avoid.

11-20-2012, 04:58 PM	#17
Jon-Lars Jon-Lars Joined: Apr 2006 Location: Beverly Oddometer: 418	__________________ Cheers, Jon-Lars Sorenson Beverly, WA http://www.facebook.com/BMWR90S

11-20-2012, 06:48 PM	#19
Jon-Lars Jon-Lars Joined: Apr 2006 Location: Beverly Oddometer: 418	Buchanan built the wheels on this one, using shouldered Akront WM3-18 front and WM5-18 rear rims. The rear rim was laced offset 12mm. This provides clearance from the big-tube swingarm. Because the tires are wide, there is plenty of "patch alignment". __________________ Cheers, Jon-Lars Sorenson Beverly, WA http://www.facebook.com/BMWR90S Jon-Lars screwed with this post 11-20-2012 at 06:59 PM

11-22-2012, 02:03 AM	#21
chasbmw Studly Adventurer Joined: Feb 2006 Location: Bath Uk Oddometer: 996	Both my airheads were greatly improved when I fitted a pair of the new Michelin pilot series tyres that are properly sized to be 3.25 and 4.00. Handling was much quicker AND more stable that the original BT45s. This is a good combination, in the wet or dry. I found that my nominal 4.00 BT45 was in actually 118mm in width, so nearly a 120. On your bike a 120 should fit with a bit of grunt in fitting it, if it rubs on the swinging arm there used to be a spacer that could be fitted to the hub to move the wheel away from the swinging arm. __________________ Charles http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg R90s 1070 replica, R90/6 1971 Commando Fastback

11-24-2012, 07:52 AM	#23
Wirespokes Beemerholics Anonymous Joined: Jul 2002 Location: Jackson's Bottom Oregon Oddometer: 7,354	I doubt the small offset to the side would make any difference to the ujoint! They're made to handle offsets, up and down, so what difference would a little to the side make? They, in fact, don't do well with no movement; it's the extremes you want to avoid. __________________ Wanted: Dead, smashed, crashed or trashed gauges BMW GAUGE REPAIRS - TACHSPEEDOCLOCKVOLT METER PODs & LIGHT BOARD*

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11-20-2012, 06:31 PM	#18
headtube ^OP Gnarly Adventurer Joined: Sep 2012 Location: Toronto Oddometer: 135	Hmm... what sort of clearance do you have on that 130? Didn't think it was possible.

11-21-2012, 10:11 PM	#20
fosterb Adventurer Joined: Dec 2011 Oddometer: 19	you got a build report somewhere? need some more info on that scoot, she looks beautiful!

11-23-2012, 06:09 AM	#22
Darryl's bmw Darby Joined: Aug 2012 Oddometer: 8	There is a spacer you can get that moves the rear wheel over about 3/16 over to the left to have the tire clear the swingarm.. Back in the racing days they ran much wider tires with a very large offset. They even compensated with an offset for the swingarm in the frame but it could be hard on the u-joint.