Replacement Tires (2016)

I had a few Norton riders tell me the K81s on my 71 750 Roadster needed replacing, but there were no cracks or other signs of decay, so not wanting to waste good rubber I persisted with them, complaining [to myself] about the tendency for the front to run wide etc, handling not how I thought a rebuilt Commando should, but nothing like a slide [in the dry at least]...
Finally I thought 'times up', put on a new set of 100/90/19 Roadriders at Ben Woolven's recommendation [and he would know]. After a bit of a hiccup [the bike shop fitted the front tyre wrong way round, the back tyre way out on the fitting lines] took her for a brisk run today and WOW, what a remarkable difference! Turned in beautifully, stuck like the proverbial to a blanket, bike transformed. Result!!! The guy in the Porsche trying to stay with me through Mooney Creek to Kariong seemed to think we were having fun, and we were. So yes, Avon Roadriders get the thumbs up from me. [PS anyone want a K81 with plenty of tread and a 2007 on the date stamp ?] Cheers.

I just changed the TT100s from my 74 850 that I have just acquired, I felt that despite them being almost new as the date codes were 1996 I should change them anyway . I’ve put on a pair of 100/90/19 roadriders as per Avon recommendation.

I had a few Norton riders tell me the K81s on my 71 750 Roadster needed replacing, but there were no cracks or other signs of decay, so not wanting to waste good rubber I persisted with them, complaining [to myself] about the tendency for the front to run wide etc, handling not how I thought a rebuilt Commando should, but nothing like a slide [in the dry at least]...
Finally I thought 'times up', put on a new set of 100/90/19 Roadriders at Ben Woolven's recommendation [and he would know]. After a bit of a hiccup [the bike shop fitted the front tyre wrong way round, the back tyre way out on the fitting lines] took her for a brisk run today and WOW, what a remarkable difference! Turned in beautifully, stuck like the proverbial to a blanket, bike transformed. Result!!! The guy in the Porsche trying to stay with me through Mooney Creek to Kariong seemed to think we were having fun, and we were. So yes, Avon Roadriders get the thumbs up from me.

It’s your choice regarding 90/90-19 size in the front. I tried it...didn’t care for the feel.

mames said:

1975 850 Commando, hasn't been ridden in a long time, has original tires and I'm going to replace them and the tubes. Specs call for 4.10-19 (both front and rear), which I have found the metric equivalent to be 110/90/19. A friend says modern design/type tires offer increased stability, etc., rather than the vintage design, but when I contact supply places such as Motorcycle Superstore they indicate such current tires are directional and they only have the front, etc. It has been so long since I have even been on a bike I admit that I don't understand what they are saying. If it is the right size and direction for the front why can't it be mounted that way for the rear? Anyway, anyone who has information and advice for me will be greatly appreciated. Thank you.

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The comment about increased stability is a bit misleading. Stability depends on your steering geometry. If the tyre changes that, it might make the bike more stable, but it probably depends more on tyre size than anything else. If you get more grip, that might be good - but the wear rate might increase. Grip usually depends on the effect of tyre temperature on the rubber compound. Some early Commandos had different steering geometry which made them less stable under certain circumstances. You should probably check which type you have and go with the recommendation of somebody who has the same model as yourself.

My race bike steers in the correct direction if you gas it when cranked over in corners - to some people, that is 'unstable'. To other people 'unstable' means twitchy.