Dominator rear tyre

I reckon the Avon SM Mk II suits the 99 perfectly. The new ones are the same rubber compound as the Roadrider and give excellent grip especially in the wet and you can corner happily in the dry until your footrests kick up sparks.

Gordon (who is just back from riding in floods, slush and ice on his Speedmaster/SM shod 99).

Stuart, just fitted new tyres to my slimline 88. 'New style' reartyre would be Roadrider 100/90 universal. check the Avon website. Good source is tyretechtrading.

regards JMB

I want to change the rear tyre on my 99 and was wondering what will be most suitable.

At the moment it's a MK11 3.50 which looks like a side car tyre. I looked at the Avon roadrider and it seems they do either a 3.25 or a 4.00 wide tyre. Would either of these be ok?

What size and make works best for this model?

I find that the best tyres are Dunlop K70 for the rear 3.50x19 and Avon ribbed 3.25x19 front wheel , this is what on my dominator 1954 model 88 and after 40 years of riding I tried all makes of tyres and these I find are the best combination , but at the end of the day its all up to you, yours anna j

I too have a '54 Dominator, which is ridden far, and fast. Avon Speedmaster, front, and Avon SM rear are more than adequate. Your 3.50 SM rear tyre has probably done a fair old mileage if it looks flat. A new SM (I fitted one in June) has quite rounded shoulders.

All my Featherbeds have the new Avon's fitted. 90/90 on the front and 100/90 on the rear. Although I have one machine with a 110 on the rear, but you need to put a threadthrough the front chain guard mounting hole because there is not enough room.for the nut.

The BIG plus is that Avon's are made in the UK, giving street cred to your bike and keeping British people in work. Even better is that they are a brilliant tyre, best I've had yet.

I've got a K70 on the rear of my dommi, and to be honest, apart from the fact it has 'Made in Japan' on the sidewall, I think it's horrible and the compound is way too hard. Ironically, it's better in the wet. On a dry, slightly dusty road it's lethal and gives you no confidence leaning into bends. It was recommended during restoration and I hadn't ridden the bike with anything else, so I can't offer a comparison. I plan to change it this year though.

Agree about the K70 on the back. On dry roundabouts which are fun with the SM Mk II, alarmingly with a K70 fitted the back end will break away and the wretched things wear out ridiculously quickly. One lasted 1200 miles of Highland roads and was a slick at the end of it.

I've got a K70 on the rear of my dommi, and to be honest, apart from the fact it has 'Made in Japan' on the sidewall, I think it's horrible and the compound is way too hard. Ironically, it's better in the wet. On a dry, slightly dusty road it's lethal and gives you no confidence leaning into bends. It was recommended during restoration and I hadn't ridden the bike with anything else, so I can't offer a comparison. I plan to change it this year though.

well my one made in england by dunlop Birmingham and I found it to be ok and alot better than the square looking Avon roadmaster Mk2 I can get Avon GP tyre if you what to, but In need at list 50 of you to order these tyres , if there is any interest just list it hear , I then get some prices . yours anna j

I'll add another vote for the SM, I have one on my 99 with a Speedmaster up front, don't see how you could improve much on that combination, excelent grip wet or dry, good mileage, even with spirited riding & it keeps the original look.

Can't comment on the Roadrider on the Dommie, but on a Commando, one started to show signs of cracking between the tread pattern very early in it's life, by the time it was half worn up, I changed it as the cracks were getting very deep & the tyre seemed to be falling appart, I just didn't trust it anymore. Investigation suggested I was not alone, a quick google search for Avon Roadrider problems will give you more info & some pictures. I believe Avon have since changed the construction &/or compound though. Gone back to AM9 Roadrunner for the Commando's.

As for K70's, English made ones were ok, although never gave me quite the same confidence that the Avon Roadrunner did, I think the foreign made ones must be a weird compound as I have to agree, they don't seem to grip well in the dry unless you get them really hot, then as Gorden says, they wear out in no time.

Regards, Tim

Ineresting Tim,

Been using the new Avon's since 2000, the last pair went on last year, I have them on five bikes on the roadwith around 16,000 miles between them and no sign of wear or damage. For me theseare early days but over the old tyres there is no contest, never an unsafe moment and that includes a few laps of the TT course. The other thing about the new Avons is that they look good too. They are fitted to my 1960 99under construction. Photo's soon.

What I particularly like about riding on a Speedmaster/SM combination isout cornering people who areriding modern bikes and seeing their utter disbelief that something on skinny tyres can do that. Oh the radiant smugness!

If your bike has a enclosed rear chaincase or even the mountings for onebe wary of any tire that increases the width above a 3.50x 19 .

Robert, I would suggest the 100/90 is near enough the equivalent of the original 3.50 rear. No problems with these.

Actually, the machine I experimented (successfully) with a 110 uses 18 inch wheels, I think that tyre is an Avon AM23 from memory but has done over 4,000 miles without showing wear. However, although the tyre works brilliantly, you will appreciate there is little more than 1/8" either side clearance at the front of the swinging arm and again, the front chain guard mount will need an internal screw to secure. I don't have a fully enclosed chain guard so can't comment.

If you want to go bigger, try a box section swinging arm, again I can't say. Anyone tried this with an even wider rear tyre?

I have a 1961 model 50 with the correct guards and enclosed chaincase. I have found that the 100/90 x 19" comes up a bit too wide. I have fitted a 3.25 x 19" Roadrider to the rear (It is universal fit) and a 90/90 x 19" to the front. The 3.25 is 98mm at the widest point.I think it maintains the right balance and makes it handle beautifully.

Paul

Since Dominators were originally designed to run with Avon Speedmaster front, an SM rear tyres, on which they handle superbly, why change? I imagine very few of these machines are ridden harder than they were by their original owners. As Gordon mentioned previously, it is possible to ground the footrests with this combination, how can you better this?

Paul, I didn't take into account the original rear mudguard, as not used.

However, I will come up against this problem very soon with my slimline 99 restoration. At least now I will be prepared to bash or cut the mudguard.

Will update soon.

Excuse me for poking my nose into this non commando/rotary thread but Johns statement "Dominators were designed to run with" etc. I tend to think the bike was designed, and Norton fitted whatever their favoured tyre manufacturer churned out. Some years ago when I told a Classic bike dealer that I was planning to change my Commando wheels for 18" items for a better selection of tyres. He said "the Commando was designed to run on TT100 tyres" That was the end of that conversation, but I wonder what would have changed in the bike design had Norton fitted Avon tyres? Now, come to think of it, didn't they come fitted with Avon tyres from new?

Thanks for that info David.

Some years ago, encouraged by a photo of a restored 99DL on a Norville article ,i asked Les for his recommendation on tyres. The tyres were duly purchased and hang on the wall as a reminder to work things out for myself.

I'm sure there will be an acceptble tollerance in the manufacturing process, whether it's enough to make a significant difference, I don't know, but rim width will deffinately affect the carcase width. The same tyre on a WM3 rim will be wider overall than if it were on a WM2 rim for example.

100/90 Roadriders actual width fitted to 2.5" width rim is 109mm, approx. 4.3in. width.

90/90 fitted to 2.15" width rims are 3.8in. width.

http://www.avon-tyres.co.uk/motorcycle/roadrider

Sometime the oldies are best! The original Norton fitment isn't made from the original material so it's irrelevant when people complain about the old Avons not having the grip of modern tyres. As far as I know the new Avons alluse the same compound - apart from racing types. So its only the tread form that changes.

Cheers, Lionel

Previously Gordon Johnston wrote:

What I particularly like about riding on a Speedmaster/SM combination isout cornering people who areriding modern bikes and seeing their utter disbelief that something on skinny tyres can do that. Oh the radiant smugness!

Just checked my Commando's, both on 100/90X19 AM9 Roadrunner tyres bought & fitted at the same time, & with similar mileage's but one is on the original WM2 rim, the other is on a WM3 rim.

On the WM2 rim the max width is 96mm, on the WM3 rim the max width is 98.5 mm, so 2.5mm wider. Not much but could make the difference if things are tight to begin with.

Previously david_evans wrote:

Excuse me for poking my nose into this non commando/rotary thread but Johns statement "Dominators were designed to run with" etc. I tend to think the bike was designed, and Norton fitted whatever their favoured tyre manufacturer churned out. Some years ago when I told a Classic bike dealer that I was planning to change my Commando wheels for 18" items for a better selection of tyres. He said "the Commando was designed to run on TT100 tyres" That was the end of that conversation, but I wonder what would have changed in the bike design had Norton fitted Avon tyres? Now, come to think of it, didn't they come fitted with Avon tyres from new?

As a matter of interest, what tyres were you using in the 50's? Norton did not fit "whatever their favoured manufacturer turned out" they fitted what they thought were the most suitable. For 650, and SS, models an Avon GP rear tyre was used, with a special inner tube. They recommended that * under no circumstances should anything other than these should be fitted to the rear wheel as replacement".

The original post was not referring to a 650, SS, a Commando, or any other model. So, I still maintain a combination of Speedmaster front, and SM rear are the most suitable combination, for a standard Dominator.

I was born in 54 John, so a mere yoof, but your statement "Dominators were designed to run with"etc is difficult to believe. The bike was designed. Then Norton fitted the most appropriate tyre available. Then they specified that tyre. The bike wasn't designed around a specific tyre. I have heard of tyres being designed for a particular car or bike but not the other way round.

Through the 1960's Avon was the most respected of tyre manufacturers, I can well imagine that Norton would have checked the effect of any developements and changes to suspension with Avon tyres being a base-line.

Fitting wider tyres can affect handling. The contact point when leant over is no longer on the vertical axis of the bike but moves inwards. This is fine if the bike geometry and suspension are designed to suit this phenomenon which I suggest the featherbed was not. The effect of fitting slightly wider tyres on your elderly Norton is probably negligible but worthbearing in mind.

O.K., if you want to be pedantic, maybe the featherbed frame was not built to match the Avon tyres. However the combination of the two produced the best handling, road going, motorcycle for over a decade. How can you beat perfection?

We are talking Dominators here, who needs a tyre suitable for over 125 m.p.h. on a bike which can barely top the "Ton" in ideal conditions?

Indeed. I have always marvelled at the instructions in the green book to increase tyre pressures to 24 front, 30 back for sustained speeds above 110 mph. 24/24 is good enough for not more than 2 minutes at up to 125mph. Someone at Norton Motors knew of a very long hill with a prevailing tail wind - and a repair shop at the bottom!

For your average modest bike thrasher, I still maintain the Speedmaster/SM Mk II combination is best. The Avon GP specified for all 650 and SS models was OK but didn't half wear out quickly. I have a part worn one in the shed where it will remain unless anyone is desperate for it.