18" rear wheel???

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I think I've read some threads or replies, that some install an 18" rear wheel on a Commando? Just curious, how it would affect the handling?
 
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63 views and no comments?

Time for a wise crack I guess. :)

Pre-Commando Nortons are 19 front 18 rear and they actually are nimble in the right hands.

The bike might feel like it is a little lighter up front and it could steer a little quicker, not sure though. It is only 1/2" less height. Haven't done it on a Commando, but own a 19" front 18" rear Norton, which is very quick steering. Might have more to do with the Betor triple clamps though.

Al should be able to come up with 2 or 3 paragraphs describing what would happen with the wheel change, and maybe throw in a mention of a turn at Winton. ;)
 

RoadScholar

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I would think that lowering the rear would increase the trail of the front, sort of going towards the "chopper" effect. Such a situation should take some of the quickness out of the handling. but make the bike a bit easier on a straight flat roadway..

Fitting an 18" rear rim increases the tire choices; the handling can be restored by selecting a tire with an appropriate aspect ratio..

Best.
 

gortnipper

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I think I've read some threads or replies, that some install an 18" rear wheel on a Commando? Just curious, how it would affect the handling?
I put 18" flanged alliy Excel WM3 on the rear with Avon AM26 4.0. It had a positive effect on the handling compared to the 19" stock with an old Roadrunner. The rolling diameter is the same. I wouldn't hesitate do it again.
 

robs ss

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I think @gortnipper 's advice is good. I have an 18" rear wheel and am very happy with it.
Just make sure the 18" rim is wide enough to take an 18" tyre with similar (same?) rolling diameter as you have - that way, no speedo problems. Don't try to go too wide or you'll have trouble fitting inside the swing-arm. About 120mm wide seems to be about right.
You won't improve handling but also won't harm it - just gives you a wider selection of dedicated rear tyres - which I think is the driving rationale.
Cheers
 

elefantrider

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I laced my cush drive hub to a 18" shouldered WM3 Akront so I can run the Battelax BT45 rear. I have since put the bike back to stock WM2 sizes and K81s (!) so will be selling my 18" rear.
 

Onder

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I went to WM3 19 on my rear. Of course, I saw no difference.
 
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The original Earles Court bikes had an 18" WM3 rim as detailed in the spec sheet given out at the show. Between the show and production it changed to 19" WM2.
 

trident sam

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I have one Commando with the stock 19 on the back and one with a wm3 x 18 on the back, Got the complete wheel second hand and I really can't tell any difference. I did it for (my) aesthetics and a greater tyre choice.
 

phippsy

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There has been plenty of talk on the forum on this subject ,18” gives you the choice of using a tyre made for the rear ,giving you a lot more depth in the tread. 19” ‘tyres are universal’ designed for front and rear and come with less depth .There are people on the forum that are far more knowledgeable on the subject than myself hopefully they willcome forward and show there wisdom
 
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I have an 18" rear on the 920 & a 19" on the 750. They both handle well & are the same diameter, but the rear 18" tyre lasts for 4000 miles while the 19" rear lasts for only 2000 miles if I'm lucky. In fact the 750 has a nearly bald rear again, & is now off the road until a new tyre arrives. Nuff said.

Martyn.
 
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Thanks for all the replies. I was curious for two reasons. My Norton is long in the turns compared to my Bonnevilles, and I think a fatter rear tire would improve the looks, no offense concours.
 
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I have a couple of Norton Commandos with an 18 inch rear rim. The tire is large enough (I forget the size) to give the same rolling diameter as the original 19 inch tire. Coincidentally or not, both my Commandos have an issue with head wobble, which as we all know could be for 999 different reasons. I have a half baked notion that the 18 inch wheel with the larger heavier tire makes the isolastics work harder, magnifies any slop in the system, and is more inclined to produce handling anomalies.
I agree with the comment that the mileage on a wider 18 inch tire is greatly improved over a stock 19 inch tire.
 
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Tornado

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For more noticeable handling change, would going to a taller rear shock set be worth considering? I changed my modern Bonneville shocks to taller Thruxton shocks and found bike noticeably quicker at corner tip in. Has anyone run different length shocks on Commando? I also had a narrower front tire put on the Bonneville at a later time and found things got too hairy for my liking.
 
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If you don't usually carry a pillion passenger, softening the rear suspension might make a Commando with 19 inch wheels handle better. As you change the trail for any given rake on the steering head, the two handling extremes are self-steering. Lowering the back makes the bike self-steer a bit more in the correct direction as you accelerate through corners. If you raise the back or lower the front, you decrease the trail, and the bike will probably tend to run wide a bit more as you accelerate out of corners, and be more difficult to tip in as you brake for a corner.
When you get the handling right, the bike should tip in easily as you brake for the corner and feel very positive as you accelerate out - on a lean.
As you accelerate, the trail increases and it reduces as you brake. So the bike steers on the throttle and the brakes. If you get into a corner too hot, you have to choose a point at which you have to stop braking and accelerate. What the bike does then, is important for your health.
 
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Accurately measuring the trail of motorcycle is not easy. But for a road or road racing bike, with 27 degrees rake, minimum trail is about 95mm - maximum trail is about 105mm. At 27 degrees rake on the steering head, the 105mm trail is excellent. You can get back on the gas straight after you have braked the first third into a corner. If you want stability, use less trail.
 
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I have a Norton front wheel (drum) with a 21" rim. The rim is very good and the tire is very good. Anyone?
 
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For more noticeable handling change, would going to a taller rear shock set be worth considering? I changed my modern Bonneville shocks to taller Thruxton shocks and found bike noticeably quicker at corner tip in. Has anyone run different length shocks on Commando? I also had a narrower front tire put on the Bonneville at a later time and found things got too hairy for my liking.
Raising the forks in the triple clamps does similar, and it is a less expensive method. Can that even be done on a stock Commando?

Putting a 18 inch rear wheel on a bike that had a 19 inch rear wheel on it previously would take about 10 minutes of riding to get accustomed to. Probably would not make a difference considering most of the good 18 inch road tires I've used have a taller aspect ratio when squeezed onto a skinny brit rim. The bike might not change at all in rear end height and handling until you squared off the top of the rear tire.
 
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I have 2 Nortons both slimlines, The 99 runs old style Avon Speedmaster/SM tyres on 19" slim std Rims ,has raised bars and weighty Craven Panniers. Handles perfectly and turns in well. Grip is a bit suspect on greasy wet roads. The Atlas has Modern tyres on 19 " Alloy rims with a WM3 on the back. Handles like a loaded truck. Would hate to have to change line mid corner. Don't ride it . Son thinks its OK , but as my brother used to ride a very bent 88 and thought it the best handling bike ever , I don't give much weight to others opinions !!.
 
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