wheel size

Ray Bear

Forum User
Non-VOC Member
Hello all, I wish to do some extended travelling on my 48 Rapide that will include some out back areas of Australia & further travelling around New Zealand & would like to replace the 20in WM1 front & the 19inWM2 rear rims for something more substantial for the trip so as I can install a better tyre that may be better load carrying & handling , comfortable & easier to replace away from home should I have a tyre failure. I have two new spare hubs already but not sure which way to go with the rims & was initially going to run with the Vincent touring spec of a 19 WM2 front & 18 WM3 rim at the rear but I may be able to do better, Can someone advise me in the right direction here. Also a part number or rim model would be handy as spoke angles may make a rim selection difficult with such small hubs...Thanks.. Bill
 

chankly bore

Well Known and Active Forum User
Non-VOC Member
I can remember doing a trip in the late 80's on a Touring Rapide.Melbourne to Goolwa,Barossa Valley,Burra,Morgan then meandering back to Melbourne.Both rims were 19"xWM2.Tyres were Dunlop K81's.Burra to Morgan was dirt road,bitumen for the rest.Maybe if I were carrying a pillion or luggage I'd go WM3x18" rear for ease of replacement.Central Wheel Works U.K. can supply rims and spokes.This combination will not make handling lighter,for that you need to go to WM1x21" whereby you will also get a more accurate speedometer.This size is fairly easy to find about the place due to our Hugely Daggly riding brethren.I also did Melbourne to Canberra via the Cann Valley Highway once in a fit of geographical whimsy;a section of about 20 miles of dirt with loose road metal cricket ball size.Tyres 3.00x20" and 3.50x19".I can categorically state that no tyre choice would have altered the experience!Good Luck.
 

bmetcalf

Well Known and Active Forum User
VOC Member
You may be assuming that the speedo is spot on with a 20". After I went to 21", I put on a bicycle speedo and found the speedo was right on the money. When I had a 20" tire (a very hard Dunlop, went to 19" in 1981), I didn't check the accuracy, though.
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
Somewhere in the literature it suggests that the speedo is more accurate with the 21" front wheel. Maybe. But 100 mph GPS is 103 speedo with my 20" front. I can live with that. And besides, what signifies is the rolling circumference of the wheel: it's got a flat at the bottom.
Nothing wrong with the standard tyres from the POV of load carrying or longevity: except that tyres are no longer made from Bakelite, so give the same total lifetime grip as they always did - but over a lower mileage, if you see what I mean. But. My advice would be to use the 'net to see what tyres are easy to get, and use those. Little consolation to know that you were doing 30 mph +/- 3 % when the 20" front tyre, a size that is impossible to obtain within three weeks, wears out.
I suspect you'd figured that already...
 

Albervin

Well Known and Active Forum User
VOC Member
My speedo has been checked by NSW's finest with a radar gun! 21" Avon ribbed is now replaced with an Avon AM20/26 100/90 so I will ask my friendly plod to check but I will argue the use of a 21" and 19" rear for any touring in the Great Southern Land! Tyres are easy to find and the bike just handles so well with that combination. I would use a 48 tooth rear sprocket (especially in NZ) as it really utilizes the mid range of a Vincent.
 

davidd

Well Known and Active Forum User
VOC Member
I ran the same as Albervin on my D Shadow. I think the 21" front gives the lightest handling and it does not get lost in holes very easily. The 48T is great for general riding.

David
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
My choice is 90x90 x21" front on a WM 3 rim, 400x18" rear on a WM 4 rim fitted with Avon Distanzia's, check the Avon web site

http://www.avon-tyres.co.uk/motorcycle/distanziaalloy's

Rims with out the flanges that collect so much crud and water. The wider rim gives the tyre much better support and if you view their the max sizes are given, another valid factor is the amount of rubber you get with these tires 5.2 mm as apposed to 3.6 mm on the front and 10.5 as apposed 8.1 mm.
After 4.5 k miles since fitting them last year the rear has 7.5 mm and front 4.3 mm left, I'm not fast with max speed 85mph but usually well loaded.
 

bmetcalf

Well Known and Active Forum User
VOC Member
When I had 19" front and rear, I only had to bring one spare tube on trips. Now, with the 21" on the front. I'll have to leave my three editions of KTB behind to make room for the second tube.
 
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