Contact patch. With the onset of winter back in Blighty, those two words take on an added significance. How do the all weather kings of the road stack up in the grime?
We’ll say it again: traction control was made for the British blacktop in winter, because – as every experienced rider knows – once you properly loose traction on the road, the chances of regaining it are slim (road going traction loss being commonly associated with surface contamination). Since the overwhelming majority of bikes out there lack TC, it’s down to rider management and… the ability of the contact patch to cope with adverse conditions.
While it is largely true that most modern tyres are incredibly capable compared to the stuff we had to put up with during the cross ply years, the statement needs some qualification. ‘Most modern tyres’ assumes a degree of equivalence which is misleading – they may all be generally competent, but demonstrably have individual strengths and weaknesses. And cross ply (or bias) construction still rules off piste – there is an argument for using it on tarmac given deteriorating road surfaces and associated speed limitations. Some also argue that bias construction represents a better start point for a winter tyre, but when you only have two wheels and utilise more than the central patch you need some flex off centre, which is where radials score. Since no manufacturer produces dedicated winter tyres for bikes (yet), it’s a case of finding something that works equally well in a wide variety of conditions. Michelin Pilot Road 3s were one of the first all purpose tyres whose renowned wet weather performance didn’t appreciably compromise dry riding. More recently, Metzler’s Roadtec Interact Z8s challenged PR 3s for the title of best all rounder, and according to review consensus did so successfully. We’ve used Z8s and PR3s extensively at BG albeit on separate machines, which makes true comparisons tricky: a lot has to be factored in. The former are a revelation for anyone expecting standard sports tourer type rubber (miles aplenty, adequate grip, lazy steering but no real sense of connection to the tyre): Z8 profiling makes even the most lardy bike keen to turn, and dry performance in general is outstanding. Both brands performed superbly in the wet, with the Z8s inspiring just a tad more confidence, taking both bikes into account. We were expecting tyre wear to be an issue compared to the ST stalwarts of yesteryear like Bridgestone 020s, but again were confounded. Wear has proved minimal to date on both sets, the Z8s ably withstanding the grunt of our tuned ZRX behemoth without undue evidence of toil as the miles rolled by.
- ↑ Who says cross plys don’t come in fat sections? Conti tractor cross ply….
Equally, both sets of tyres have may have been implicated in problematic scenarios. Finding out how things cope in more extreme conditions is in the job description, and riding the ZRX very rapidly in a straight line into a choppy headwind prompted the front end to get uncharacteristically lively, prompting thoughts of adding a steering damper to the long list of mods the bike has undergone. It would be wrong to attribute this flightiness directly to the Z8s, since suspension settings can play their part in this kind of scenario (an excellent road surface notwithstanding), and high speed nakeds present their own unique handling challenges – even in near perfect conditions. On the other hand the ZRX has proven a surprisingly capable straight liner, not easily given to high jinks. Both PR3s and Z8s were prone to occasional white line tracking, and wet cat’s eyes caused minor slippage, as one would expect. The PR3s came unstuck – literally – riding down a shitty unclassified road at night in cold weather on our previous hack, the redoubtable SV650. A mere feathering on the brakes was enough sign off traction completely, which was never recovered. Again, it is hard to specifically blame the tyres, since we were as close to off road conditions as a supposedly metalled surface can get.
The point here is that even the best tyres have limitations, and proper testing in adverse conditions helps define them. In both cases (ZRX and SV, Z8s and PR3s) it is probable that different tyres would have coped differently when things livened up – but for better or worse remains open to question. One thing we do know: different tyres would almost certainly have been less competent all rounders that either the Michelins or Metzlers. Make no mistake, these tyres are as close to race wet performance as you can get in road legal guise – with no trade off when it finally stops raining. If forced to choose between them, we’re both agreed here that we’d take the Z8s. Given how good the PR3s are, this represents a major achievement by Metzler. It isn’t a no brainer: if you can source either set significantly cheaper than the other, that’ll be the way to go.