Tire recommendations for a 72 interstate

I'll be replacing the K81's on my 72 this winter. I'm not a big fan of the K81's. I like the K70's, but they don't come in the sizes that would work. I recently installed a set of Avon Roadriders on my 14 T100. I really like them, and I believe the 100/90 would work on the rear, and a 90/90 would be good for the front. Before I proceed, I'd like to know what folks here think.

Thanks for all replies.

I have also been looking for tyres. Avon Roadriders are a specified tyre for certain road racing in the UK. To me that does not mean much, because the officials in controlling bodies are susceptible to incentives from suppliers. I like Bridgestome Battlaxe tyres which can be supplied in a race compound, but in Australia, we often find we get sold short. I doubt the race compound is available here. In my case, it probably does not mean much anyway, because I was brought-up racing on shit tyres, so I am not very tyre-dependent. But better is always good.
I use the size combination you have suggested on my Seeley, but it has 18 inch wheels. You might find the large tyre on the back changes the rake on your steering head and slightly alters the handling. If the rake becomes slightly steeper, your bike might tend to become less responsive in corners.

I have been running Bridgestone BT45's on mine for nearly 20 years - love them. Only down side is that to get a proper rear tire, you need to go to an 18" rim. I have heard tell of guys running a BT45 100/90-19 front on the rear, but I have no experience with that.

Currently, I am running a 100/90-19 on the front and 110/90-18 on the rear. Got over 5000 miles out of my last rear - almost lasted the entire season.

I've been happy with the Roadriders. Can't comment on using the smaller size on the front as I have not tried that. With the same size on both, I can move the front to the back and put a new one on the front to keep it fresh as it wears very little compared to the back.

the 90/90 on the front will lighten the steering BUT will make it less stable at speed. it depends on your riding style and conditions. if your not into canyon carving or quick mountain roads than you might like the 100/90 better.

Tanks for the replies. I really thought the 100/90 on the front may be a little wide, there is not very much clearance from the fender stays with 4.10's. I do not race, and I am not an aggressive rider. I find myself backing off, as I enter the turns on this bike, when compared my all of my triumphs.

I would like a little more meat on the back myself, but don't wish to give up the 19" wheel. I enjoy the current handling and am leery of experimenting, so shall stay where it is until I happen across someone else's adventures to paradise.

When you set your bike up, you usually adjust the spring tension on the rear shocks. How much the bike squats affects the handling. If a fatter rear tyre changes the attitude of the bike, you can adjust (lower) the rear ride height, which will bring the rake (trail) back to where it is safer.
Because my bike does not have isolastics and has 18 inch wheels, stability is never a problem. The steering damper is there in case I lose the front and get the tank-slapper. When you change from 19 inch wheels to 18 inch, the bike usually becomes more stable and more difficult to get around tight corners, because you effectively change the trail when you decrease the wheel size. On a featherbed-framed bike, it is very noticeable.

acotrel said:

I have also been looking for tyres. Avon Roadriders are a specified tyre for certain road racing in the UK. To me that does not mean much, because the officials in controlling bodies are susceptible to incentives from suppliers. I like Bridgestome Battlaxe tyres which can be supplied in a race compound, but in Australia, we often find we get sold short. I doubt the race compound is available here. In my case, it probably does not mean much anyway, because I was brought-up racing on shit tyres, so I am not very tyre-dependent. But better is always good.
I use the size combination you have suggested on my Seeley, but it has 18 inch wheels. You might find the large tyre on the back changes the rake on your steering head and slightly alters the handling. If the rake becomes slightly steeper, your bike might tend to become less responsive in corners.

Click to expand...

The 90/90 19"" front and 100/90 19 rear AM26s have only been a control tyre in the Lansdowne series, in race compounds and in those specific sizes.

They are used by Manx Norton and G50/7R riders who had to fit 19" rims to use them.

In my mind this has no bearing at all when considering road tyres. I shall be using a pair of the AM26 race tyres in the 19" sizes on my Suzuki 500 twin race bike, where the 19" rims have been retained for maximum ground clearance which can be a problem with these bikes! In race tyres I have no other choice. None. To use another tyre I would need to use different rims. But honestly I expect them to be a good choice anyway.

I have used a 90/90 18" front AM 26 race tyre on another bike, and bizarrely an AM 26 rear road tyre on a GSXR750F race bike. They are great tyres in race compounds and used by choice by a lot of competitive riders.

They also seem to me to be good tyres in road compounds and a lot of contributors here have used them. But maybe racers should butt out here, we really don't have much useful to say on things like tyre life, wear patterns and white lining!

acotrel said:

When you change from 19 inch wheels to 18 inch, the bike usually becomes more stable and more difficult to get around tight corners, because you effectively change the trail when you decrease the wheel size.

Click to expand...

Nope, wrong again. If you change both wheels to smaller diameters, you decrease the bike's trail which makes the bike less stable and makes for lighter more responsive steering. I imagine the diameter change yields such a small of a change in trail length that a normal rider probably couldn't tell any difference in handling unless the bike already had a pretty small trail to begin with.

I get tired of correcting you, because you're a "racer", or at least you never stop reminding us of that... It wouldn't be half as annoying to read your proclamations, if you would learn the physics so your stories would at least align with the known science....

Anyone feel free to correct me if I'm wrong...

I'm glad I went with the 100/90-19 Avon Roadrider MKIIs front and back. I measured the 100/90 on my T100 Bonneville, and it is slightly wider than the ones on this Norton. I suspect it may be the rim width. I'll have to wait till spring to try em out. I went ahead and changed em now, because I'm installing the K81's on a BSA I'm building. Thanks for all the replies.