Tyres.....again.

[Motu]

I fitted my Michilen T63 yesterday - oh man what a mission,even with a tyre machine! The sidewall is very stiff,and then trying to stuff the thick heavy duty tube in...and the rim lock.One things for sure,I'll never be able to do a road side repair with this one,and I don't think pressure will mean a thing,it's rock hard with zero pressure! It's very round in profile as you can see,and good side knobs that wrap around and won't bend,should be a good road tyre,but no flex could make it suspect off road.

But I want to talk about the old Kenda K760 Trackmaster I took off - check it out! The sprotsbike riders are going to take one look at it and say I don't go around corners because it's worn flat.....then they will go on about how stupid it is to ride with a tyre like that,it'll have to lift up the get to the edge of the tyre and then it'll be on those narrow side knobs...blah,blah,blah.....

Not so - when the bike leans over,and it does so very well....those side knobs fold over,and it actualy runs on the inside of those outer knobs,that's why it wears flat....not because I ride in straight lines.It walks,wobbles and steps out at various times,but fairly predictable,and as that's my third one I know them pretty well.My front K760 is more worn on the side knobs - the seal wears out the sides,the middle wears out on gravel.You can see a big cut,and a side knob ripping off...

Hey,and what about my new mower - I sold some scrap alloy for $100,a couple of days later another scappy comes in and shows me what he found on the side of the road....so I bought it off him for $90,everyones a winner.

[warewolf]

It's very round in profile as you can see,and good side knobs that wrap around and won't bend,should be a good road tyre,but no flex could make it suspect off road.

"Lookin' good, Vern"

Those trapezoidal side knobs are reminiscent of the Pirelli MT21, which I reckon explain its excellent tarmac cornering. Shame about the carcass stiffness.

[slowpoke]

Not so - when the bike leans over,and it does so very well....those side knobs fold over,and it actualy runs on the inside of those outer knobs,that's why it wears flat....not because I ride in straight lines.It walks,wobbles and steps out at various times,but fairly predictable,and as that's my third one I know them pretty well.

AH HA!! So that explains it. I've seen a few big trailies with this sort of wear and I could never figure out why they look so corner-phobic. With that sort of action going on as you're riding, a straight road bike must seem pretty ho hum eh? Smiles for miles and all under the speed limit.

[Ixion]

Yes. I find that the XT600 with boring Trailwings is cornering near as hard as a Velo Venom (there is nothing beyond that - take your GSXZXRCBR1000 things and hide in the c0rner)

It squirms and wriggles and twitches but it holds on. I wish we'd had tyres like this when I owned a Velo.

[PLUG]

[QUOTE=Motu;761371]

Not so - when the bike leans over,and it does so very well....those side knobs fold over,and it actualy runs on the inside of those outer knobs,that's why it wears flat....not because I ride in straight lines.It walks,wobbles and steps out at various times,but fairly predictable,and as that's my third one I know them pretty well.My front K760 is more worn on the side knobs - the seal wears out the sides,the middle wears out on gravel.You can see a big cut,and a side knob ripping off...


... interesting ... a question ... running a tkc80 on the front ... the centre blocks are wareing down on the back edge (in the direction of rotation) of these blocks ... the back edge of the block has 2-3mm less material to the carcass than the front of that same block ... have & am playing with tyre pressures, road work running mid 30's at the moment ... these pressures make it more lively/responcive in the tip it into corners department ... had me own theory as to why i'm getting this wear pattern & that is brakeing ... something like ... under front brakeing suspension compresses & weight transfer ... tyre flattens out/compresses & its the back edge thats feeling this more than the front, hence the wear ???

Any advances/ideas/explanations on this ???

[warewolf]

the centre blocks are wareing down on the back edge (in the direction of rotation)

You're right on the money. It's typical front tyre wear. A combination of braking loads and probably some element of the front being pushed by the back under drive. Occurs on all bikes, just is more pronounced on a widely-spaced knobby tire. Same thing happens on road bikes.

The TKC80 on the front of the 640 is just shy of 9000km. It's getting pretty horribly out of shape despite having plenty of tread depth. On advrider recenty someone recommended turning the tyre around to even out the wear. Might give it a go soon. They are directional tyres so I wouldn't recommend high-speed high-load runs with it reversed...

[Bartman10]

Motu - how many k's did you get out of your old tyres?

[Oscar]

I just stuck some TK80's on the 950.
The rear is a 150x70/18 wooohooo!!!

[Motu]

Motu - how many k's did you get out of your old tyres?

Uh,dunno - I seldom look at the odo as it's on another mode in the digital display....maybe 2,000km.With so much wheelspin the DT destroys tyres on gravel.

After a 300km ride on seal gravel and a little off road with a river crossing I'm happy with my setup.The T63 is great,and the IRC GP22 copes well....although I reckon I'll struggle in mud or soft sand with the front.So I'll stay away from the challenge sections if it's wet....Vege has me worried laying down a hard line with tyre choices on the Kaipara 200,I don't want to prove him right.

[Henk]

Ahmen on the hard line tyre choice thing. I might get some old S12s out of the shed yet. The front tryre wear thing is very typical. Had an MT21 on a while ago where the back edge of the knobs ended up below the carcass of the tyre, worrying. Had another reason for the flat rear tyre profile show up a while ago. At higher speeds the shock on the 600 wasn't keeping up, I thought the clutch was starting to give out but the back wheel was constantly leaping off the deck and spinning up. Still couldn't keep up with the litre plus sprotsbikers from work though.