Tyre Question

[Waylander]

Ok I don't think this is really important but it's something I've been a little curious about. On tyres is it a big thing that they have a channel/tread thing that runs down the center of the tread range like this picture?


Does it really matter? I had Cheng shin (SP?) on my bike when I first bought it (crap tyres I know I know but they only cost me about $60USD for the pair, I had just spent $3500USD on bike, jacket, helmet..) and they had that line. Problem was that everytime I changed lane and there happend to be a gap in the concrete the tire would get wobbly. It wasn't major but enough to scare me. (new rider at the time)

I asked my dad and he said ya they do that and the line is what caused it. Something about the edges of the line and the edges of the concrete. Anyway once I had the money I put a set of Metzler ME880s (Picture attached.) on it and never had that problem again. Got these becouse my dad always used and trusted metzler and becouse these didn'thave that line. Havn't noticed anything else different other than the wobble is gone.

[John]

Nah each have there different properties they are designed for dispersing water effectivly in R&D all tires should be sweet

edit: doh, didnt read - probably were dead tires bad preasures and shit etc etc

[Posh Tourer :P]

The wobble can be caused by the profile of the tyre. Even if the tyre is ostensibly the same size, the curvature can be different. I doubt it is the line, my old Rille 12 Metzeler (look up the tread pattern....) never did that, though smaller tyres often do

[Ixion]

Oh boy, now you've done it. Another religious war.

Older bikers have passionately defended positions on the merits or otherwise of their favourite tyre tread pattern

General answer to your question is , it depends on the bike.

A longitudinal groove will improve high speed straight line stability and make the bike less tender - ie less prone to "fall into" a corner.

For various reasons these were considered desireable attributes on earlier bikes (stopping tank slappers for one thing!) . So front tyres often had a tread pattern consisting entirely of grooves. The good old Avon Speedmaster for instance. We all used it. To me there is still something a bit freaky about seeing a block pattern tread on a front tyre.

Downside of the extra stability (apart from the fact that maybe you didn't actually want that) was that if the tyre encountered ANOTHER directionally stable pattern (like a ridge or groove in the road) the two tended to "fight it out" to see which won. The "wobble" you speak of.

Like all tyre things it's a case of trial and error to see what works for your bike and riding style and preferences.

A longitudinal groove will also help with water dispersion though there are other ways to deal with this.

All the above only my opinion. And highly likely to be ferociously challenged by zealots of a different tyre-religion .

[Waylander]

Thanks for the answeres so far. This was just something I've been surious about (as stated) for a while and it poped into my head tonight for some reason. Knew I wouldn't be able to sleep till I got an answere.

Wouldn't have though that it could start a war Ixion, I mean they're just tires. Everyone uses what they feel is best for them as you said.

I'll probably stay with the ME880s for the Virago but when I get myself a sporty I might decide something else works best for that bike, aslong as it doesn't have the centre line lol.

[John]

I didnt read the first post so ignore my reply ... I am to drunk to be saine atm.

[Waylander]

By the way, how do I check tread depth and how deep should it be so that I know when I'll need new tires? Other than when the bike starts to feel loose in the turns I don't know how to tell.

And John, I never really listen to you this late at night anyway lol

[John]

Tire depth on a larger bike if you ride hard should be more than 2mm (IMO)...
Check on the center, and both sides.

Replace all if its worse than 2mm.

See I can be helpfull

[Coldkiwi]

After Ixion's very insightful post, I feel rather unqualified (ok, even more than usual) but here's what I know...
There has been a theory (makes sense to me) that a longitudinal groove in the front makes a lot of sense to disperse standing water in the middle of the contact patch when upright. The longitudinal groove in the back however is not as necessary given that the front tyre has probably dispersed most of the water by the time the rear comes along. You can see this with pirelli MT21 and 22's on smaller cc bikes.

Check tread depth by finding the lowest point and sticking a match in the groove. for WOF requirements you need 1.5mm which is the equivalent of a standard match head.

[Lou Girardin]

ME 33 fronts are a really good match for ME880's and give you more front grip.

[Motu]

Wish that match head rule was official,I'd sell a shit load of tyres.Ribbed tyres can induce a speedwobble on a buckled rim....well it did for me,going back to dirt tyres fixed that.As for the Avon Speedmaster MKII - next classic meeting check out Trigger's Luckhurst/Norton,he has a race compound one on the front and it's completely bald on the sides,I always stir him about it,but he reckons it's great.

[NC]

Anyone seen how strong the NZD is against the USD of late?
Going pretty damn good

[Ixion]

Wish that match head rule was official,I'd sell a shit load of tyres.Ribbed tyres can induce a speedwobble on a buckled rim....well it did for me,going back to dirt tyres fixed that.As for the Avon Speedmaster MKII - next classic meeting check out Trigger's Luckhurst/Norton,he has a race compound one on the front and it's completely bald on the sides,I always stir him about it,but he reckons it's great.

that would be logical, cos if the rim is buckled the ribs wont be circular . At the buckle point they'll be distorted.So instead of holding the bike in a straight line, they'll hold it in a "straight line, now veer left , now veer right, now back to strainght again" line.

[DingDong]

I dont know shit and niether did the tech tyre guys in the olden days.

Get Pilots... they're premo

[Motu]

that would be logical, cos if the rim is buckled the ribs wont be circular . At the buckle point they'll be distorted.So instead of holding the bike in a straight line, they'll hold it in a "straight line, now veer left , now veer right, now back to strainght again" line.

Just proved to me knobs were better than road tyres,but I knew that anyway,but it took a 80mph speed wobble to get me back on the right track.Street tyres are bloody dangerous.