Aloha everybody,just wanted to share my experiences with tires for these old girls. When I bought my first Earls fork bike 12 years ago,I wanted to be true to the vintage aspect of these machines,and when I sourced tires I went with the obvious Metzeler block C's. I fitted these to both of my Earls fork bikes,they seemed to ride well and very stable in a straight line/upright riding, however, I have the good fortune of my neighborhood having a downhill corkscrew similar to Laguna Seca, we get sportbike riders all the time visiting us, so they can "lean it over". Riding this road on the vintage tread tires,the rear ends did not seem planted,it was squirrely, and not confidence inspiring to say the least. I later acquired a R67/2 with Avon tires and this bike, with the modern tread was the best handling of my 3. I later made the decision to move away from the vintage style tread due to wanting a safer,better riding machine,than being true to the vintage equipment. It is difficult to size tires for the Earls fork,since there are very few 3.50X18 available,so I tried the 100-90 X18 and these are simply to low on the sidewall profile,enough to change the effective gear ratio, about 3/8" difference in circumference! I lived with these for awhile,and they still outperformed the block C's,but the engine would rev higher at cruising speeds. I took a chance and purchased the 110-90X18 Avon road rider Mk2,and these are THE BEST I have ever tried. They JUST fit under the front fender,and you have to wiggle them into the rear but they do fit and do not rub. The slightly taller gearing is not too noticeable (I figure they are like having a 4.00X18 on the back) and the riding experience is transformed! These tires,with their round profile/cross section will make the bike seem more "tippy" at first compared to the flat/almost car style Metzeler tire, but you can lean it over and it feels sure and smooth, and the biggest IMPROVEMENT was almost no tram lining at all! In Hawaii we have many roads and our freeways all have rain grooves in them. The vintage tread tires tram line and grab these grooves making it a butt-puckering experience,and I avoid freeways at all costs. The first thing I did after getting these tires was hitting the freeway on my R69S and I got it up to 70+ mph and it rode great. Nothing scary and totally ridable . If you are going for concourse points at a show,or want " vintage street cred" then stick with the old style tread pattern, however if you like to lean it over a little and hit the freeway, the Avon road riders are terrific. I will NEVER go back to a vintage tread style unless I am building a show queen(which I will never do, these were made to RIDE). The difference is so dramatic I had to write about it!
Thanks for the information, I plan on starting with the 100/90 x18 and if it revs to high I will change. I live in New England and stay off the highways, according to the trip computer on my GS the average speed is 45mph
These tires are mounted on a front and rear direction,there are arrows on the sidewall showing which way to mount for front or rear fitment. I have never enjoyed riding this bike as much as I do now,with the stiffer shocks (IKON and Hagon) and these tires,it is a completely different machine.
Going to replace the 45+ year old tires on the R69S my dad left me, and am really grateful you sharing this post. Are you still loving these tires? Have you found any alternatives you are considering next time?
I agree, that the Avon Road riders do make the bike handle better. I have them on my R50S, and it feels better when you encounter rain groves than the vintage tread patterns.
Vech
Technical Adviser, Former owner, Bench Mark Works
662 312 2838 cell 9 am to 4pm CST PLEASE!
What's the right size of Avon Roadrider for an R27 (3.25x18)? I've read 90/90, is that correct? Also, what kind of mileage do you get? I've only run Heidenau K34, which are cheaper, and handle great in my opinion, but I only get 3,000 miles on the rear, and would be open to better options for cost-per-mile.