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T120 - a wider tyre, pros and cons? #104837
11/05/06 9:21 pm
11/05/06 9:21 pm
Joined: Sep 2006
Posts: 26
UK
J
Johann T Offline OP
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Johann T  Offline OP
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J

Joined: Sep 2006
Posts: 26
UK
I'm just about to order new rims for the 1969 T120 Triumph Bonneville I'm restoring. (see http://bonneville.typepad.com for more about the bike).

Standard rims are WM2-18 for the front, and WM2-19 for the rear. However, the wheel-building company has suggested I go for the standard WM2-18 on the front but a wider WM3-19 on the back.

I can see that a wider rear tyre makes sense in terms of increased road grip, but are there any other pros and cons I should be aware of in terms of handling etc before I make a final decision?

Any words of wisdom gratefully received,

Johann T
http://bonneville.typepad.com

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Re: T120 - a wider tyre, pros and cons? #104838
11/05/06 9:27 pm
11/05/06 9:27 pm
Joined: May 2005
Posts: 3,849
ohio
shel Offline
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shel  Offline
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ohio
if I were your wheel builder I would suggest you put the 18" on the rear and the 19" up front laughing


When given the choice between two evils I picked the one I haven't tried before
Re: T120 - a wider tyre, pros and cons? #104839
11/05/06 9:33 pm
11/05/06 9:33 pm
Joined: Sep 2006
Posts: 26
UK
J
Johann T Offline OP
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Johann T  Offline OP
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UK
My mistake - it's been a long weekend. I should of course have referred to an 18" on the rear and 19" up front. My fault, not the wheel-builders.

All the same, does anyone have any experience (good or bad) of a WM2-19 on the front and a WM3-18 on the back?

JT

Re: T120 - a wider tyre, pros and cons? #104840
11/05/06 9:41 pm
11/05/06 9:41 pm
Joined: May 2005
Posts: 3,849
ohio
shel Offline
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shel  Offline
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ohio
i was just having a little fun with you.
my parts catalogue list a wm3-18 as standard for 1969. was this different for home market models?


When given the choice between two evils I picked the one I haven't tried before
Re: T120 - a wider tyre, pros and cons? #104841
11/05/06 9:57 pm
11/05/06 9:57 pm
Joined: Sep 2006
Posts: 26
UK
J
Johann T Offline OP
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Johann T  Offline OP
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UK
Hi Shel -

I've just re-examined my parts book and although the WM2-18 appears to be standard for the UK bike, it DOES list at the foot of the page a WM3-18 as an alternative rim for a 4 inch tyre. I hadn't noticed this before. Thanks for causing me to take a closer look! :-)

Re: T120 - a wider tyre, pros and cons? #104842
11/05/06 10:04 pm
11/05/06 10:04 pm
Joined: Aug 2001
Posts: 1,907
The Northwoods... Michigan
Steve Erickson Online content
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Steve Erickson  Online Content
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The Northwoods... Michigan
I think that the "home" models came stock with a 3.50X18 on the rear on a WM2-18, whereas the export models, at least those to the US, had a 4.00x18 on a WM3-18 rear as standard. Some models even had different side stands because of the tire size, I believe.

Re: T120 - a wider tyre, pros and cons? #104843
11/05/06 11:07 pm
11/05/06 11:07 pm
Joined: May 2005
Posts: 3,849
ohio
shel Offline
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shel  Offline
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ohio
i wish they would have gave us the big tank as well laughing


When given the choice between two evils I picked the one I haven't tried before
Re: T120 - a wider tyre, pros and cons? #104844
11/06/06 10:48 am
11/06/06 10:48 am
Joined: Oct 2004
Posts: 4,429
Melbourne Australia
Tiger Offline
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Melbourne Australia
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by shel:
<strong> i wish they would have gave us the big tank as well bigt

Johann, you could easily end up with tyre/chainguard clearance problems if you go too wide with a rear tyre and std chainguard.
A 110 Avon is very close on my '69 Tiger.


1969 TR6R
7.62 x 51 is not a maths puzzle.
Re: T120 - a wider tyre, pros and cons? #104845
11/06/06 11:57 am
11/06/06 11:57 am
Joined: Sep 2006
Posts: 26
UK
J
Johann T Offline OP
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Johann T  Offline OP
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J

Joined: Sep 2006
Posts: 26
UK
Thanks for the clearance advice. The bike definitely has a WM2-18 on the rear. Do you think I will have clearance problems if I go for a WM3-18?

Re: T120 - a wider tyre, pros and cons? #104846
11/06/06 12:20 pm
11/06/06 12:20 pm
Joined: Aug 2001
Posts: 3,913
Houston Texas
Britbodger R.I.P. Offline
In Remembrance
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Houston Texas
Johann,

I can verify that models exported to the US have a 18" WM3 rim on the rear so should be OK on your bike. Actually, I have a WM4 rim on my Triumph that I use for Proddie racing and it works fine.

As Tiger has pointed-out its more the tire width that you need to be concerned about. In this regard there is no clearance problem with the original 4" K70's that were fitted stock. However you have to be carefull when selecting a more modern tire. In the case of Avon Road Runners/Super Venoms that are very popular the widest you can get away with without the tire rubbing the chainguard is 90/110 (4.33") as Tiger has already stated. However, if you are prepared to run without the chainguard or alternatively cut a slot in it a 90/120 (4.72") will fit OK. That is what I have done with my T120 and BSA Rocket Three.

HTH

Re: T120 - a wider tyre, pros and cons? #104847
11/06/06 5:35 pm
11/06/06 5:35 pm
Joined: Feb 2006
Posts: 111
Peasmarsh, East Sussex
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Micknal Offline
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Posts: 111
Peasmarsh, East Sussex
Johann

I had exactly the same decision to make when rebuilding my 69 TR6 over the last few years.
It was only when I spoke to the very reputable Tony Miller at the then Miller Motorcyles,Hastings ,that I made my mind up and went for the stock WM3-18. I was able to source a new old Avon Roadrunner R2 100/90 that was a bit difficult to fit to the rim but didn't give me any clearance problems with the chainguard.
On the original WM2-19 front I have fitted an Avon Roadrunner AM20 which has performed fine this summer.
BTW Tony also advised against drilling the rim and fitting the security bolt as all I was using the bike for was pleasure riding as against speed trials or other high performance riding.
HTH.


Mick
1969 TR6
Re: T120 - a wider tyre, pros and cons? #104848
11/07/06 6:40 am
11/07/06 6:40 am
Joined: Jun 2002
Posts: 10,239
Scotland
S
Stuart Offline
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Scotland
Hi Johann,

Quote:
Originally posted by Johann T:
the WM2-18 appears to be standard for the UK bike,
I believe it's actually a typo - if you look in other Triumph publications for the model, and in other years, you'll find WM3-18 for the rear rim on a UK & GE bike; also, if you look at the other bikes in the range, they were all specified for WM2-19 front and WM3-18 rear.

Hth.

Regards,


Moderated by  John Healy 


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