On the rear, the 110/90-18 has often been substituted by previous owners with a 120/90-18.  I do not recommend this -- although the wider tyre will perform satisfactorily, the 2.15" rear rim is a little narrow for a 120, and the effect will be to squeeze the tyre somewhat.  A squeezed tyre has several undesirable effects: first of all, it makes the profile more triangular, thus distorting the design handling characteristics; it concentrates wear in the centre of the tread, encouraging the tyre to "square off" and wear more rapidly than designed; and the wider tyre makes turn-in more sluggish, which rather defeats the light quick handling of this bike.

This is one of the few matched pairs that is actually "correct" for the original design of the bike.  These general purpose tyres from Avon should wear well, handle nicely (thanks in part to a front tyre that's actually narrow enough for the rim), and have good stability and traction.  The drawbacks of the Roadrunner front only show up at sustained high lean angle, as in hard continuous twisty strafing, and aside from that these should perform well for every other sort of riding.

You certainly can't beat the price of the Kendas.  For that price, these are outstanding tyres.  They handle well, last well, and would be just as competitive if they were 50% more expensive.  While other tyres do offer better wet and dry traction, if you need to save money this is the way to go.  My concern, though, is the ability of the Kenda front to handle the wet, and the tendency to accentuate any weaving on the highway.  Fortunately the Kenda rear works well with almost any front, like the inexpensive but excellent Dunlop 491.

For any sporting riding, the Avon Super Venom is a superb choice for an older motorcycle like the Seca.  It has excellent traction, good stability, a confidence-inspiring profile, and on a bike like the Seca should also last fairly well.  I'd definitely pick these over the other choices available.

This is a tough one for me.  Although the Avon Roadrunners have good enough compound to keep me happy, I like to use all the lean angle in twisty strafing, which with the Roadrunner AM20 tends to heat up the outermost row of tread blocks a bit too much -- but then again, the Seca is a light bike and doesn't put that much of a load on the front anyway.  At the same time, I'd like to go with a 90/90, because the profile effects of the slighty-squeezed 100/90 would be more obvious at high lean angle.  What to do, what to do...

In the end, I think I'd have to go with the Roadrunners.  The benefits of running the narrower front outweigh the stick of the Super Venoms, and in any case the suspension and chassis of the small Seca aren't really up to ultra-sticky rubber.  The Roadrunners give good sharp handling with highway stability, and bring out how much fun this bike really is.

Avon

Bridgestone

Continental

Dunlop

Firestone

IRC

Kenda

Metzeler

Michelin

Pirelli

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